U.S. patent application number 13/331054 was filed with the patent office on 2012-06-21 for camshaft adjuster.
This patent application is currently assigned to SCHAEFFLER TECHNOLOGIES GMBH & CO. KG. Invention is credited to Stefan SCHELTER, Juergen WEBER.
Application Number | 20120152188 13/331054 |
Document ID | / |
Family ID | 44883086 |
Filed Date | 2012-06-21 |
United States Patent
Application |
20120152188 |
Kind Code |
A1 |
WEBER; Juergen ; et
al. |
June 21, 2012 |
CAMSHAFT ADJUSTER
Abstract
An arrangement of a camshaft adjuster which has a drive wheel, a
stator and a rotor. The camshaft adjuster is held together via
sleeves arranged coaxially with respect to the axis of
rotation.
Inventors: |
WEBER; Juergen; (ERLANGEN,
DE) ; SCHELTER; Stefan; (DOTTENHEIM, DE) |
Assignee: |
SCHAEFFLER TECHNOLOGIES GMBH &
CO. KG
Herzogenaurach
DE
|
Family ID: |
44883086 |
Appl. No.: |
13/331054 |
Filed: |
December 20, 2011 |
Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 1/3442 20130101;
F01L 2001/34469 20130101; F01L 2250/04 20130101; F01L 2001/34483
20130101; F01L 2303/01 20200501; F01L 2301/00 20200501; F01L
2001/34423 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2010 |
DE |
10 2010 063 703.3 |
Claims
1-10. (canceled)
11. A camshaft adjuster, comprising: a drive wheel having an axis
of rotation; a stator; a rotor having a degree of freedom of
rotation in relation to the stator and being fixed axially in
relation to the stator; an adapter sleeve; and a connecting sleeve,
the adapter sleeve and the connecting sleeve being arranged
coaxially with respect to the axis of rotation of the drive wheel,
and the adapter sleeve and the connecting sleeve firstly being
connected to each other and secondly fixing the rotor, the stator
and the drive wheel in place axially.
12. The camshaft adjuster according to claim 11, wherein the
adapter sleeve is connectable to an end of a camshaft.
13. The camshaft adjuster according to claim 11, wherein the
adapter sleeve is of oil-conducting design.
14. The camshaft adjuster according to claim 11, wherein the
adapter sleeve has an axial stop for fixing the drive wheel in
place.
15. The camshaft adjuster according to claim 11, wherein the
adapter sleeve and the connecting sleeve each have an axial stop
for fixing the rotor in place.
16. The camshaft adjuster according to claim 11, wherein the
connecting sleeve has an axial stop for fixing the stator in
place.
17. The camshaft adjuster according to claim 11, wherein the drive
wheel is mounted on the adapter sleeve.
18. The camshaft adjuster according to claim 11, wherein the
adapter sleeve or the connecting sleeve has a thread.
19. The camshaft adjuster according to claim 11, wherein the
adapter sleeve is connected to the connecting sleeve with an
allowance for fit.
20. The camshaft adjuster according to claim 11, wherein the drive
wheel has a step with a diameter at which, the stator is centered
and a torque is transmitted.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority of DE 10 2010 063 703.3
filed Dec. 21, 2010, which is incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The invention relates to a camshaft adjuster.
BACKGROUND OF THE INVENTION
[0003] Camshaft adjusters are used in internal combustion engines
in order to vary the control times of the combustion chamber
valves. Adaptation of the control times to the current load reduces
the consumption and the emissions. A widespread design is the vane
cell adjuster. Vane cell adjusters have a stator, a rotor and a
drive wheel. The rotor is generally connected to the camshaft for
conjoint rotation. The stator and the drive wheel are likewise
connected to each other, wherein the rotor is located coaxially
with respect to the stator and within the stator. Rotor and stator
form oil chambers which can be acted upon by oil pressure and
permit a relative movement between stator and rotor. Furthermore,
the vane cell adjusters have diverse sealing covers. The assembly
of stator, drive wheel and sealing cover is formed via a plurality
of screw connections.
[0004] DE 10 2008 029 692 A1 shows an assembled camshaft with a
vane cell adjuster. Said vane cell adjuster is fastened to the
camshaft end by a central screw. All of the individual parts are
fixed and braced at the camshaft end by means of the central screw.
A sealing cover is subsequently connected to the drive wheel,
sealing cover and drive wheel together creating an oil-tight
space.
SUMMARY OF THE INVENTION
[0005] It is the object of the invention to specify a camshaft
adjuster which is of particularly simple construction and has a
reliable connection to the camshaft.
[0006] According to the invention, this object is achieved in that
the camshaft adjuster has a drive wheel, a stator and a rotor. The
rotor has a degree of freedom of rotation in relation to the
stator, and the rotor is fixed axially in relation to the stator.
The camshaft adjuster has an adapter sleeve and a connecting sleeve
arranged coaxially with respect to the axis of rotation of the
drive wheel. The adapter sleeve and the connecting sleeve are
firstly connected to each other and secondly fix the rotor, stator
and drive wheel in place axially.
[0007] The effect achieved by this is that a plurality of axially
bracing connections in the camshaft adjuster are dispensed with.
The rotor, the adapter sleeve and the connecting sleeve form a
conjointly rotating unit which can be connected to one camshaft
end. A multiplicity of screws, rivets and pins can be dispensed
with as a result.
[0008] In a refinement of the invention, the adapter sleeve is
designed to be connectable to one camshaft end. In this case, the
camshaft end is designed in such a manner that the adapter sleeve
is centered via a collar or step. Said centering minimizes
concentricity errors. Furthermore, that end of the adapter sleeve
which is on the front side and faces the camshaft forms an
advantageously planar contact surface with the camshaft in order to
absorb high forces, The centering means and the contact surface can
advantageously be textured on the surface by, for example,
knurling, in such a manner that the reliability of the connection
is increased.
[0009] In an advantageous refinement, the adapter sleeve is of
oil-conducting design. The conducting of oil through the adapter
sleeve forms short oil paths, and low oil losses can be obtained by
the coupled components having a small number of sealing points.
Further sleeves used in the camshaft adjuster can likewise be of
oil-conducting design. The sleeves used can be provided with
sealing elements.
[0010] In a particularly preferred refinement, the adapter sleeve
and the connecting sleeve have one or more axial stops. Said stops
form positional fixing, wherein the rotor is braced and the drive
wheel and the stator are provided with a small amount of axial
play. The integral formation of said stops in the form of changes
in diameter on the outer surface areas of the adapter sleeve and of
the connecting sleeve is advantageous here.
[0011] In a refinement of the invention, the adapter sleeve has a
mounting for the drive wheel. The adapter sleeve is advantageously
designed to be connectable by the mounting directly to the camshaft
end. Since a camshaft mounting is generally arranged at the
camshaft end, forces are advantageously absorbed at the cylinder
head.
[0012] In a preferred development, the adapter sleeve is connected
to the connecting sleeve by a thread. The possibility of removal is
advantageous in this case. Internal and external threads and
left-handed and right-handed threads can be used in this case.
Furthermore, a thread-rolling formation on one of the two sleeves
is conceivable.
[0013] In a further refinement of the invention, the connecting
sleeve is braced to the adapter sleeve by a connection with an
allowance for fit or an interference fit. The effect achieved by
this is that, when the camshaft adjuster is installed at the
camshaft end, the central screw further reinforces and secures the
interference fit. The interference fit can be designed more
efficiently by milling the surfaces of the sleeves.
[0014] In one development of the invention, the stator is connected
in a form-fitting manner to the drive wheel and is centered on the
latter. The form-fitting connection transmits the torque from the
drive wheel to the stator. With the centering, a seal forming an
oil-tight space in the stator can be provided. The axial holding
together between the stator and the drive wheel is formed via axial
stops and by the connection between adapter sleeve and connecting
sleeve.
[0015] As an alternative, in order to form the torque transmission
between stator and drive wheel, use may also be made of pins,
rivets or other standard parts. The advantage of using standard
parts is the low production costs.
[0016] In an advantageous development of adapter sleeve, connecting
sleeve and the outside diameters thereof, the drive wheel, the
stator and the rotor are particularly well centered with respect to
one another and a very precise positioning with respect to one
another is achieved. For this purpose, the outside diameters are
designed to differ in diameter from one another. Drive wheel,
stator and rotor are advantageously centered on a common outside
diameter which can be produced simply and cost-effectively.
[0017] Functions, such as centering and axial fixing in place, can
optionally he realized via further sleeves. For this purpose, for
example, one of the sleeves can have a centering means for a stator
and a further sleeve can have a centering means for a rotor, etc.
Any combination of the functions and the number of sleeves is
conceivable.
[0018] In an optional refinement of the invention, the adapter
sleeve, the connecting sleeve and optionally further sleeves can be
connected to one another with additional means. Means of this type
may be screws, disks, rings, pins or the like.
[0019] In a particularly preferred development, the sleeves have a
passage opening for the penetrating arrangement of a central screw
which fastens the camshaft adjuster to the camshaft end. A sealing
cover or a covering hood, which seals off the unit in an oil-tight
manner in relation to the environment, can subsequently be arranged
on the unit.
[0020] Further individual parts of the adjustment unit, such as
sealing covers, bearings, locking units or oil-conducting plates,
can be fixed in place by the adapter sleeve and the connecting
sleeve and by additional sleeves.
[0021] In an advantageous refinement, the assembly of stator, rotor
and drive wheel and of further components is formed via just one
sleeve. In this case, the components to be mounted are inserted
onto the sleeve, centered and brought against the stops of the
sleeve, and the assembly created is subsequently secured. Securing
means may be snap rings, securing rings, nuts, screws or,
advantageously, the sleeve itself. In this case, the material of
the sleeve is crimped, bent or deformed in some other way.
Formation of the sleeve in sheet metal is advantageous.
[0022] In a particularly preferred development of the invention,
the end surface of the adapter sleeve on the camshaft side has an
encircling depression concentrically with respect to the center
axis. Said depression is connected to oil supply bores of the
camshaft. Axially parallel bores which intersect said depression
extend in the adapter sleeve. The bore outlets open out at the
other end of the adapter sleeve in a first oil chamber.
Furthermore, the adapter sleeve has a concentric passage opening.
Said passage opening is penetrated by a central screw. In this
case, a gap remains between central screw and diameter of the
passage opening. Said gap constitutes a further means of supplying
oil. The adapter sleeve has radial oil bores which connect the
outside diameter to the inside diameter of the passage opening. In
this case, the radial oil bores are designed to he offset at an
angle to the axial oil bores so that the bores do not intersect and
therefore there is no short circuit in the oil circuit. The radial
oil bores advantageously open out into the outside diameter, which
constitutes the bearing point for the drive wheel, in order to
lubricate said bearing point. As an alternative, the radial oil
bores may also open out into an encircling groove from which the
oil is then conducted further into the corresponding oil
chamber.
[0023] The oil ducts can optionally be arranged in an
oil-conducting sleeve oriented at an angle to an oil supply source.
In order to be able to realize an angle-oriented supply of oil
between the sleeves, the sleeves have elements securing against
rotation. A reliable arrangement of the oil ducts can therefore be
formed.
[0024] Furthermore, a sleeve can have a thread for fastening to a
camshaft. As a result, the fastening with a central screw can
advantageously be omitted, and the sleeves are formed without a
passage bore for a central screw. The thread can be designed as an
internal or external thread and can advantageously have a
left-handed or right-handed thread based on the direction of
rotation of the drive wheel.
[0025] As an alternative, in order to reduce the weight, the
sleeves used can be designed to be hollow on the inside, or to be
perforated or slotted or in the form of a cage. In order to
increase the rigidity, the cavities can have a filling, for example
made of metal foam.
[0026] In a concretization of the invention, a hub which is located
at one end of the stator formed on the stator. Said huh can
advantageously be determined by the sheet metal thickness of the
stator. The hub supports the stator on a sleeve, preferably the
connecting sleeve.
[0027] A spring element is arranged between the stator and the
rotor. The spring element braces the stator to the rotor in an
advantageous direction. The coil body of the spring is
advantageously mounted or guided on an outside diameter of one of
the sleeves used, for example the adapter sleeve. The spring can
optionally also be guided on the huh of the rotor or of the stator
or on other components.
[0028] In a further development of the invention, the sleeves used,
or at least one thereof, is designed as a sheet metal part. This
reduces production costs. As an alternative, use may also be made
of other manufacturing methods, such as sintering, extrusion, deep
drawing or milling. Accordingly, the use of a multiplicity of
materials, such as metals, plastics or composite materials, is
conceivable. In order to minimize wear, coatings can be
provided.
[0029] In a favored development of the invention, the camshaft
adjuster is fastened to the camshaft end by a central screw. The
central screw penetrates the sleeves which are used and which hold
together the camshaft adjuster per se. The screw head makes contact
in the assembly with one of the sleeves, preferably the connecting
sleeve. In this case, it is advantageous for the camshaft adjuster
to be able to be preassembled by the use of sleeves and to
subsequently be able to be fastened to the camshaft just with a
central screw.
[0030] In a further refinement of the invention, the central screw
has a concentric passage opening which extends from the screw head
as far as the end on the thread side. Said passage opening is used
for the oil conduction. The oil conducting means is advantageously
designed as a means of venting or recycling the oil emerging from
the stator into the covering hood into the cylinder head.
[0031] In a refinement of the invention, the oiltightness is
ensured by means of a covering hood. The covering hood is
advantageously mounted subsequently after assembly of the adjuster.
The covering hood can have a sealing ring. As an alternative, a
sealing cord, for example consisting of liquid plastic, can be
applied, advantageously prior to assembly, to the covering hood and
then, upon fitting of the latter, produces the sealing
function.
[0032] In an advantageous refinement, the covering hood has snap-on
hooks which are distributed around the circumference and can engage
in complementary openings in the drive wheel and connect the two
components to each other. In this case, the covering hood is
advantageously formed from plastic or sheet metal.
[0033] The covering hood can be fastened to the camshaft adjuster
with a further sleeve or with a sleeve which has already been
used.
[0034] An arrangement without a covering hood may be advantageous
in order to form a "belt in oil" camshaft adjuster.
[0035] By means of the arrangement according to the invention of
sleeves, in particular an adapter sleeve and a connecting sleeve,
and the action of said sleeves, a compact camshaft adjuster
assembly is produced, which assembly can be connected to one
camshaft end by an advantageous formation of a sleeve. Distortions
due to local screw connections are avoided, and an increased
service life and low production costs are achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] Exemplary embodiments of the invention are illustrated in
the figures, in which:
[0037] FIG. 1 shows a section through a camshaft adjuster which is
fastened to one camshaft end;
[0038] FIG. 2 shows a sleeve which is designed as an adapter
sleeve;
[0039] FIG. 3 shows a further view of FIG. 2;
[0040] FIG. 4 shows a section through a connecting sleeve;
[0041] FIG. 5 shows a drive wheel which can be mounted on the
adapter sleeve; and
[0042] FIG. 6 shows a section through the mounting of the drive
wheel on the adapter sleeve.
DETAILED DESCRIPTION OF THE INVENTION
[0043] FIG. 1 shows a camshaft adjuster 1 and a camshaft end 5. The
camshaft adjuster 1 has a drive wheel 2, a stator 3, a rotor 4, a
disk 47, a locking means 6, a restoring spring 7, and an adapter
sleeve 9 and a connecting sleeve 10. In this case, the arrangement
furthermore has a central screw 8 and a covering hood 46.
[0044] The camshaft adjuster 1 is designed as a vane cell adjuster,
wherein pressure chambers (not illustrated specifically), which can
be pressurized with oil, are formed between the rotor 4 and the
stator 3. Oil is supplied via the camshaft end 5 through the oil
bores 18, 19 and through the oil bores 20 which opens out into a
gap between the screw stem 24 of the central screw 8 and an inside
diameter of the central camshaft bore 15. In this case, the oil
passes first of all into the adapter sleeve 9, from which the oil
can be conducted by means of further arrangements of oil bores and
oil grooves the interior of the camshaft adjuster 1 and to the
pressure chambers. The formation of the oil conduction through the
adapter sleeve is explained in FIG. 2 and FIG. 3.
[0045] The drive wheel 2 is mounted on the adapter sleeve 9. A
rotor 4, which is of cup-shaped design in the form of a deformed
part, adjoins the latter, by means of an integrated locking means
6, in the axial direction coaxially with respect to the drive wheel
2 and the disk 47. The rotor 4 is mounted on the adapter part 9 by
means of a hub. A stator 3, which is likewise of cup-shaped design
in the form of a deformed part, surrounds the rotor 4 and the disk
47. The disk 47 serves here as a sealing element. The stator 3, at
one end thereof, is centered and connected in a form-fitting manner
on a step 23 to the drive wheel 2 so that torques of the drive
wheel 2 can be transmitted to the stator 3. The restoring spring 7
is arranged within the rotor 4 and outside the adapter sleeve 9.
The restoring spring 7 braces the rotor 4 rotatably to the stator
3. The connecting sleeve 10 is subsequently connected to the
adapter sleeve 9 such that the rotor 4 is braced to the connecting
sleeve 10 and the adapter sleeve 9 for conjoint rotation and at the
same time the components fitted one inside another, such as drive
wheel 2, stator 3, rotor 4, are axially secured. At the same time,
the components are centered by the assembly of adapter sleeve 9 and
connecting sleeve 10. There is a small amount of play in the radial
direction and axial direction between the connecting sleeve 10 and
stator 3 so that deformations arising from the operation cannot
result in jamming.
[0046] Furthermore, FIG. 1 shows that the camshaft adjuster 1 is
fastened to the camshaft end 5 for conjoint rotation by means of a
central screw 8. In this case, the camshaft adjuster 1 is arranged
together with the adapter sleeve 9 on a receptacle 21 of the
camshaft end 5. The adapter sleeve 9 and the receptacle 21 together
form a means of centering the camshaft adjuster 1. In addition, a
covering hood 46 is connected to the drive wheel 2 by a snap
connection. A seal 12 forming the camshaft adjuster in an oil-tight
manner is provided between covering hood 46 and stator 3. Venting
by means of a coaxial venting duct 11 formed in the central screw 8
guides leakage oil to a further section of the camshaft bore 15 and
back to the venting bores 16 in the camshaft end 5. In this case, a
thread 25 locally separates off the camshaft bore 15 the venting
bores 16 from the oil supply 20.
[0047] A camshaft adjuster 1 shown according to FIG. 1 can be
assembled such that first of all a drive wheel 2 is fitted onto the
adapter sleeve 9, followed by the disk 47. Subsequently, the rotor
4 is fitted together with the locking means 6, the stator 3 and the
restoring spring 7 such that the restoring spring 7 can act between
the stator 3 with the rotor 4 and, by means of locking, the locking
means 6 defines a position of stator 3 and rotor 4. Stator 3, rotor
4, restoring spring 7 and locking means 6 are subsequently then
pushed coaxially onto the adapter sleeve 9 in such a manner that
the rotor 4 finds an axial stop and a centering means on the
adapter sleeve 9, the stator 3 being centered on the drive wheel 2
for conjoint rotation.
[0048] This assembly which is created is subsequently secured by
the connecting sleeve 10.
[0049] Furthermore, the camshaft adjuster 1 can then be fastened to
one camshaft end 5 by a central screw 8 and optionally, in the case
of a design of a traction mechanism drive without oil, can be
formed in an oil-tight manner with a covering hood 46.
[0050] FIG. 2 shows an adapter sleeve 9 which is of oil-conducting
design. The oil can be conducted through the oil bores 20, which
are mentioned at the beginning and are not illustrated in this
figure, from the central bore 26 via radial oil bores 32 to an oil
groove 31, which then distributes the oil around the circumference
and said oil is conducted through further duct formations (not
illustrated) between stator and drive wheel into a first working
chamber. A second working chamber is supplied by the oil bores 18,
19 mentioned at the beginning, wherein the oil is then conducted
further via oil bores 33 which open out into the restoring spring
centering means 29. The adapter sleeve 9 has a central bore 26
which is provided for the penetration by a central screw 8. The
axial stop 27 is provided for fixing the drive wheel 2 in place on
the hearing diameter 28. Oil can be conducted via the oil groove 31
to lubricate the bearing point of the drive wheel 2.
[0051] Furthermore, the adapter sleeve 9 has a restoring spring
system 34 and a restoring spring centering means 29. The axial stop
35 at the tapering end of the adapter sleeve 9 is provided for
fixing a rotor in position. The rotor here is connected
frictionally against said stop 35 for conjoint rotation by means of
the connecting sleeve 10. The centering 30 of the rotor forms an
aligned and coaxial arrangement of the rotor with respect to the
axis of rotation 22. The inside diameter of the central bore 26 has
a thread (not illustrated specifically).
[0052] FIG. 3 shows a further view of the adapter sleeve 9 and the
opening out of the oil bores 33 into an axial oil groove 36 on the
end side. The oil groove 36 on the end side is bounded here in a
sealing manner by the stop 27 and the central bore 26. The radial
oil bores 32 open out on the inside into the central bore 26 and on
the outside into the encircling oil groove 31 on the bearing
diameter 28.
[0053] FIG. 4 shows a sleeve which is designed as a connecting
sleeve 10. The connecting sleeve 10 here has a thread 38 and a
central bore 37. In order to brace the rotor 4 with the adapter
sleeve 9, an axial stop which extends radially outward is formed.
Said stop is adjoined by a step 40 which constitutes a
play-associated bearing point for a stator 3. By means of a further
axial stop 41, the stator 3 and also the drive wheel combination
are held together by the stop 27, which is mentioned in FIG. 2, of
the camshaft adjuster 1. The lugs 42 form a complementary shape for
the engagement of a tool with which the connecting sleeve 10 can he
fitted.
[0054] FIG. 5 shows the formation of a drive wheel 2 in sheet
metal. In this case, the drive wheel 2 has a toothed contour 13 for
a toothed belt and a rim 14 for the positional fixing of same.
Furthermore, a hub 43 is arranged on the central bore 44 of the
drive wheel 2. Bulges 45 which are distributed uniformly around the
circumference extend between hub 43 and toothed contour 13 and are
arranged in an alternating manner with the configuration of a step
23 in the direction of rotation about the axis of rotation 22. Via
said configurations of the step 23 and the bulges 45, oil ducts can
be formed and a form-fitting connection for transmitting a torque
between stator and drive wheel realized.
[0055] FIG. 6 shows a detailed view of the drive wheel 2 with the
central bore 44 thereof in the hub 43 on the bearing diameter 28 of
the adapter sleeve 9. When the camshaft adjuster 1 is installed at
the camshaft end 5, the stop 27 which is designed as a step is
enclosed by the receptacle 21 so as to realize centering via the
diameters of said bearing point, an oil supply and sheet-like
contact.
List of Reference Numbers
1) Camshaft Adjuster
2) Drive Wheel
3) Stator
4) Rotor
5) Camshaft End
6) Locking Means
7) Restoring Spring
8) Central Screw
9) Adapter Sleeve
10) Connecting Sleeve
11) Venting Duct
12) Seal
13) Toothed Contour
14) Rim
15) Camshaft Bore
16) Venting Bores
17) Axial Bearing
18) Oil Bore
19) Oil Bore
20) Oil Bore
21) Receptacle
22) Axis of Rotation
23) Step
24) Screw Stein
25) Thread
26) Central Bore
27) Stop
28) Bearing Diameter
29) Restoring Spring Centering Means
30) Rotor Centering
31) Radial Oil Groove
32) Oil Bores
33) Oil Bores
34) Restoring Spring System
35) Axial Stop
[0056] 36) Oil groove
37) Central Bore
38) Thread
39) Axial Stop
40) Step
41) Axial Stop
42) Lugs
43) Hub
44) Central Bore
45) Bulges
46) Covering Hood
[0057] 47) Disk
* * * * *