U.S. patent application number 14/416615 was filed with the patent office on 2015-07-02 for camshaft adjuster.
This patent application is currently assigned to Schaeffler Technologies GmbH & Co. KG. The applicant listed for this patent is Schaeffier Technologies GmbH & CO. KG. Invention is credited to Stefan Schelter.
Application Number | 20150184557 14/416615 |
Document ID | / |
Family ID | 48184202 |
Filed Date | 2015-07-02 |
United States Patent
Application |
20150184557 |
Kind Code |
A1 |
Schelter; Stefan |
July 2, 2015 |
CAMSHAFT ADJUSTER
Abstract
A camshaft adjustment device for an internal combustion engine,
having a stator (1) that can be driven by a crankshaft of the
internal combustion engine, having a rotor (3) that can be
connected rotationally conjointly to the camshaft, having working
chambers which are arranged between the stator (1) and the rotor
(3) and which are divided into first and second pressure chambers
(A, B) by vanes (18) assigned to the rotor (3), wherein, in the
rotor (3) there are provided first pressure medium ducts (5) which
issue into the first pressure chambers (A) and second pressure
medium ducts (6) which issue into the second pressure chambers (B),
wherein the rotor (3) has an inner ring (15) and an outer ring (14)
which are connected to one another by means of a disk-shaped web
(9), and the first pressure medium ducts (5) are arranged on one
side of the web (9) and the second pressure medium ducts (6) are
arranged on the other side of the web (9), and the first and second
pressure medium ducts (5,6) are formed by pressure medium guiding
sleeves.
Inventors: |
Schelter; Stefan;
(Dottenheim, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffier Technologies GmbH & CO. KG |
Herzogenaurach |
|
DE |
|
|
Assignee: |
Schaeffler Technologies GmbH &
Co. KG
Herzogenaurach
DE
|
Family ID: |
48184202 |
Appl. No.: |
14/416615 |
Filed: |
April 24, 2013 |
PCT Filed: |
April 24, 2013 |
PCT NO: |
PCT/EP2013/058464 |
371 Date: |
January 22, 2015 |
Current U.S.
Class: |
123/90.17 |
Current CPC
Class: |
F01L 1/3442 20130101;
F01L 2001/3445 20130101 |
International
Class: |
F01L 1/344 20060101
F01L001/344 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 23, 2012 |
DE |
10 2012 212 858.1 |
Claims
1-8. (canceled)
9. A camshaft adjuster comprising: a stator drivable by a
crankshaft; a rotor rotatably fixedly connectable to the camshaft;
working chambers situated between the stator and the rotor, the
working chambers divided into first and second pressure chambers by
vanes assigned to the rotor; first pressure medium channels being
provided in the rotor, the first pressure medium channels emptying
into the first pressure chambers, and second pressure medium
channels emptying into the second pressure chambers; the rotor
including an inner ring and an outer ring connected to each other
by a disk-shaped web; and the first pressure medium channels being
situated on one side of the web, and the second pressure medium
channels being situated on an other side of the web.
10. The camshaft adjuster as recited in claim 9 wherein the first
and second pressure medium channels are formed by pressure medium
guiding sleeves.
11. The camshaft adjuster as recited in claim 9 wherein the inner
ring and the outer ring are situated concentrically with respect to
each other.
12. The camshaft adjuster as recited in claim 10 wherein first
pressure medium guiding sleeves of the pressure medium guiding
sleeves are situated in a first plane, and second pressure medium
guiding sleeves of the pressure medium guiding sleeves are situated
in a second plane.
13. The camshaft adjuster as recited in claim 12 wherein the first
plane is situated in parallel to the second plane.
14. The camshaft adjuster as recited in claim 12 wherein the first
and second pressure medium guiding sleeves are situated
equidistantly from each other in the first and second planes in the
circumferential direction.
15. The camshaft adjuster as recited in claim 10 wherein the
pressure medium guiding sleeves are formed by straight tube
sections.
16. The camshaft adjuster as recited in claim 10 wherein the first
and second pressure medium guiding sleeves have identical masses.
Description
[0001] The present invention relates to a camshaft adjuster.
BACKGROUND
[0002] Camshaft adjusters are used in modern internal combustion
engines for optimizing the consumption and performance values and
are used to change the opening and closing points in time of the
gas exchange valves. For this purpose, the camshaft adjuster
includes a stator which is drivable by the crankshaft and a rotor
which is rotatably fixedly connectable to the camshaft. Working
chambers, to which a pressure medium may be applied and which are
divided into oppositely acting pressure chambers by vanes assigned
to the rotor, are provided between the rotor and the stator. During
the operation of the internal combustion engine, both pressure
chambers are permanently filled with pressure medium, so that the
rotor and the stator are connected to each other relatively
rigidly. The control times of the gas exchange valves are then
changed, in that the pressure is increased in one of the pressure
chambers, while the pressure is reduced in the other pressure
chamber. For this purpose, the pressure medium must be supplied to
the one pressure chamber and removed from the other pressure
chamber. To avoid causing the system to vibrate, the inflow of the
pressure medium must, in principle, be controlled by the outflow of
the pressure medium.
[0003] Pressure medium channels must furthermore be provided in the
rotor, which empty from the hub of the rotor into the pressure
chambers of the rotor. The pressure medium channels are fluidically
connected in two groups each to two annular spaces, which are
provided radially internally on the rotor, and are separated from
each other pressure medium-tight and to which pressure medium may
be applied with the aid of a central valve. For this purpose, the
central valve includes a spring-loaded valve body, which is movably
situated in a control sleeve and which is movable against the
spring force with the aid of an actuator in the control sleeve. A
complex geometry of control edges is provided in the control
sleeve, with the aid of which the pressure medium flowing through
the valve body flows out into the annular spaces, the pressure
medium channels and finally into the pressure chambers. For this
purpose, the valve body has a hollow design and closes and opens
certain flow paths using different control edges as a function of
its position, so that the pressure medium flows into the first
pressure chambers in one position of the valve body and into the
second pressure chambers in another position, while it flows out of
the respective other pressure chambers into a tank.
[0004] The regulating speed of the camshaft adjuster as well as the
vibration behavior of the moving parts is greatly dependent on the
own weight of the parts, the rotor, in particular, as a
particularly large mass, significantly influencing the control
behavior. For reasons of use in vehicle manufacturing, it is, in
principle, also desirable to use components having a low own
weight. For this reason, recesses are already provided in the rotor
to the extent permitted by the course of the pressure medium
channels.
SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide a
camshaft adjuster having a preferably low own weight and a
preferably simply structural design.
[0006] The present invention achieves the object with the aid of a
camshaft adjuster;
[0007] The present invention provides that the rotor has an inner
ring and an outer ring, which are connected to each other by a
disk-shaped web, and the first pressure medium channels are
situated on one side of the web and the second pressure medium
channels are situated on the other side of the web.
[0008] The advantage of the provided camshaft adjuster is to be
seen in that the rotor has a significantly lower weight, due to the
provided design having the inner ring, the outer ring and the web
connecting the inner ring and the outer ring. The pressure medium
is supplied separately to the first and second pressure chambers
and then through the web, so that the web has the function of
separating the pressure medium flows in addition to connecting the
outer ring and the inner ring. Furthermore, a prevolume is created
for accommodating pressure medium due to the cavities created
laterally to the webs, which may be introduced back into the
pressure chambers, for example by utilizing the camshaft
alternating torques.
[0009] It is furthermore provided that the first and second
pressure medium channels are formed by pressure medium guiding
sleeves. The pressure medium guiding sleeves are much lighter than
the solid material previously used, including the pressure medium
channels situated therein. Moreover, due to the provided
arrangement of the pressure medium guiding sleeves on different
sides of the web, a simpler basic structure is achieved, which has
a very high rigidity of the rotor, since the web may be preferably
situated in the middle between the inner ring and the outer ring. A
sufficient clearance for situating the pressure medium guiding
sleeves thus remains on both sides of the web, so that they may be
situated laterally offset from each other, and annular spaces which
are spaced axially apart and are separated from each other
pressure-medium-tight may be connected to the pressure medium
system. The pressure medium guiding sleeves are furthermore
separated from each other by the web, due to the provided
arrangement, so that a hydraulic short circuit between pressure
chambers A and B may be prevented in the event of possible leakage
of the connecting points of the pressure medium guiding sleeves
into the openings of the inner ring and the outer ring.
[0010] It is furthermore provided that the inner ring and the outer
ring are situated concentrically to each other, so that a
preferably uniform distribution of mass results with preferably
little imbalance. Since the rotor rotates together with the
camshaft at a relatively high rotational speed, an imbalance is
particularly disadvantageous for the operating life of the camshaft
adjuster itself and the operating life of the entire internal
combustion engine.
[0011] According to another preferred specific embodiment of the
present invention, it is provided that the first pressure medium
guiding sleeves are situated in a first plane and the second
pressure medium guiding sleeves are situated in a second plane. Due
to the provided arrangement of the pressure medium guiding sleeves,
they may be connected to the pressure medium system with the aid of
preferably narrow, annular spaces which are separated from each
other pressure medium-tight, a mass compensation being furthermore
particularly easy to implement, due to the provided
arrangement.
[0012] The structure and the mass compensation may be further
simplified in that the first plane is situated in parallel to the
second plane, and/or the first and second pressure medium guiding
sleeves are situated equidistantly from each other in the planes in
the circumferential direction.
[0013] It is furthermore provided that the first and second
pressure medium guiding sleeves are formed by straight tube
sections. Due to the provided design of the pressure medium guiding
sleeves, the mass distribution may be further simplified. In
addition, cost-effective series-production parts may be used.
[0014] It is furthermore provided that the first and second
pressure medium guiding sleeves have identical masses, whereby the
mass compensation may be further simplified.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The present invention is explained in greater detail below
on the basis of one exemplary embodiment. The following are shown
in detail in the figures:
[0016] FIG. 1 shows the stator and rotor of a camshaft adjuster
according to the present invention;
[0017] FIG. 2 shows the rotor in sectional direction A-A; and
[0018] FIG. 3 shows an oblique view of the rotor.
DETAILED DESCRIPTION
[0019] Apparent in FIG. 1 are a stator 1 and a rotor 3 of a
camshaft adjuster according to the present invention, which has a
basic structure known from the related art, including stator 1,
which is drivable by a crankshaft, and rotor 3, which is rotatably
fixedly connected to a camshaft, which is not illustrated. Stator 1
includes a toothing 2 on its outside, with which a drive chain
engages, which transmits the rotary motion of the crankshaft in
rotation direction "D." Stator 1 is provided with inwardly directed
projections 4, which divide the cavity between stator 1 and rotor 3
into working chambers. The working chambers are further divided
into pressure chambers A and B by vanes 18 situated on rotor 3,
vanes 18 being supported on stator 1 with their radial outsides
with the aid of seals 8. Pressure medium channels 5 and 6 are
provided in rotor 3, to which pressure medium is applied by an oil
pump with the aid of a central valve, which is not illustrated, or
which remove the pressure medium to a tank with the aid of the
central valve. Pressure medium channels 5 and 6 empty into pressure
chambers A and B, the pressure medium being removed into a tank
from pressure chamber A or B to which pressure medium is not
applied when pressure is applied to one of pressure chambers A or B
by the oil pump.
[0020] Pressure medium channels 5 and 6 are each designed as
pressure medium guiding sleeves in the form of short, straight tube
pieces of equal length and mass. First pressure medium channels 5
empty into first pressure chambers A, and second pressure medium
channels 6 empty into second pressure chambers B. In the
illustrated exemplary embodiment, rotor 3 includes four vanes 18
and correspondingly four first pressure chambers A and four second
pressure chambers B, which are separated from each other by vanes
18. First pressure chambers A and second pressure chambers B differ
from each other in that they are situated in groups on the same
side of vanes 18, so that rotor 3 is rotated clockwise with respect
to stator 1 when pressure is applied, for example to first pressure
chambers A.
[0021] Rotor 3 is formed from an outer ring 14 and an inner ring
15, which are connected in the middle with the aid of a web 9 in
the form of a disk. The disk has a constant width in the radial
direction, so that inner ring 15 and outer ring 14 are situated
concentrically with respect to each other, as is also apparent in
FIG. 3. Radially outwardly directed vanes 18, which divide the
working chambers into pressure chambers A and B, are provided on
outer ring 14. The disk connects outer ring 14 and inner ring 15 in
the middle, so that clearances 7 are present laterally to the disk,
as is apparent in FIG. 2. First openings 11 and 13 are furthermore
provided in inner ring 15 and in outer ring 14, respectively,
laterally to the disk on one side, and second openings 10 and 12
are provided on the other side, into which the pressure medium
guiding sleeves are inserted. First openings 13 in outer ring 14
empty into first pressure chambers A, and second openings 12 in
outer ring 14 empty into second pressure chambers B in an edge
section of outer ring 14 adjacent to vanes 18. First openings 11
and 10 in inner ring 15 empty into annular spaces 17 and 16
provided radially on the inside of inner ring 15, to which pressure
medium may be applied with the aid of the central valve, which is
not illustrated.
[0022] The pressure medium guiding sleeves may preferably be made
of steel. Alternatively, pressure medium guiding sleeves made of
aluminum or plastic could also be used. The pressure medium guiding
sleeves may preferably have a round cross section, but
alternatively also an oval, polygonal or even square cross section.
The fastening of the pressure medium guiding sleeves on inner ring
15 and on outer ring 14 may take place, e.g., with the aid of a
thread, an integral fit, a form-locked fit or a force fit. The
pressure medium guiding sleeves preferably all have the same mass
and identical dimensions, so that rotor 3 has a preferably minor
imbalance, due to an identical arrangement of the pressure medium
guiding sleeves in the radial direction and an equidistant
arrangement in the circumferential direction.
[0023] It is furthermore important that first pressure medium
channels 5 and second pressure medium channels 6 formed by the
pressure medium guiding sleeves are situated in groups on different
sides of web 9, so that a hydraulic short circuit between pressure
chambers A and B may be prevented by web 9, even in the event of a
possible leak of the connecting points of the pressure medium
guiding sleeves in openings 10, 11, 12, 13 of inner ring 15 and/or
outer ring 14. Surprisingly, it has furthermore turned out that,
due to the laterally offset arrangement of first and second
pressure medium channels 5 and 6, it may be ensured that a small
remnant of pressure medium always remains in pressure chambers A
and B and in the prevolume between outer ring 14 and inner ring 15
or in the pressure medium guiding sleeves, even in the "advance"
and "retard" stop positions, so that a small amount of pressure
medium is present in the camshaft adjuster even during the cold
start phase, which at least reduces uncontrolled movements of rotor
3 with respect to stator 1.
LIST OF REFERENCE NUMERALS
[0024] 1 Stator [0025] 2 Toothing [0026] 3 Rotor [0027] 4
Projections [0028] 5 First pressure medium channels [0029] 6 Second
pressure medium channels [0030] 7 Clearances [0031] 8 Seals [0032]
9 Web [0033] 10 First opening [0034] 11 First opening [0035] 12
Second opening [0036] 13 Second opening [0037] 14 Outer ring [0038]
15 Inner ring [0039] 16 Annular space [0040] 17 Annular space
[0041] 18 Vanes [0042] A, B Pressure chambers [0043] D Rotation
direction
* * * * *