U.S. patent application number 16/441486 was filed with the patent office on 2020-01-23 for module of a variable valve drive of an internal combustion engine.
This patent application is currently assigned to Schaeffler Technologies AG & Co. KG. The applicant listed for this patent is Schaeffler Technologies AG & Co. KG. Invention is credited to Wolfgang Christgen, Volker Schmidt.
Application Number | 20200025043 16/441486 |
Document ID | / |
Family ID | 69147822 |
Filed Date | 2020-01-23 |
United States Patent
Application |
20200025043 |
Kind Code |
A1 |
Schmidt; Volker ; et
al. |
January 23, 2020 |
MODULE OF A VARIABLE VALVE DRIVE OF AN INTERNAL COMBUSTION
ENGINE
Abstract
A module of a variable valve drive of an internal combustion
engine is proposed that includes a push rod mounted longitudinally
in a cylinder head of the internal combustion engine. The push rod
is actuated by a linear actuator that includes an armature that
makes contact, at least indirectly with the push rod, to displace
it in a first longitudinal direction. A switchable rocker arm with
a coupling slide arranged transversely to a longitudinal extent or
side of the rocker arm corresponds to an actuating finger that
extends from the push rod. The coupling slide includes a slide part
that projects laterally from the rocker arm and can be acted upon
by a free end of the actuating finger. Kinetic energy of the push
rod is dissipated or converted at least partially via a separate
damper in the first longitudinal direction before it reaches a
final position.
Inventors: |
Schmidt; Volker;
(Burgbernheim, DE) ; Christgen; Wolfgang;
(Seukendorf, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Schaeffler Technologies AG & Co. KG |
Herzogenaurach |
|
DE |
|
|
Assignee: |
Schaeffler Technologies AG &
Co. KG
Herzogenaurach
DE
|
Family ID: |
69147822 |
Appl. No.: |
16/441486 |
Filed: |
June 14, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F01L 1/185 20130101;
F01L 2820/03 20130101; F01L 1/46 20130101; F01L 1/22 20130101; F01L
2001/186 20130101; F01L 13/0005 20130101; F01L 2305/00 20200501;
F01L 1/267 20130101 |
International
Class: |
F01L 1/22 20060101
F01L001/22; F01L 1/18 20060101 F01L001/18; F01L 1/46 20060101
F01L001/46 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 18, 2018 |
DE |
10 2018 117 338.5 |
Claims
1. A module of a variable valve drive of an internal combustion
engine, comprising a push rod configured to be mounted
longitudinally in a cylinder head of the internal combustion
engine, the push rod having an actuating finger; a linear actuator
having an armature, the armature configured to displace the push
rod in a first longitudinal direction; a switchable rocker arm
having a coupling slide arranged transversely to a longitudinal
side of the switchable rocker arm, the coupling slide arranged to
be actuated by the actuating finger; and as the push rod is
displaced by the linear actuator, kinetic energy of the push rod is
dissipated at least partially by a damper.
2. The module as claimed in claim 1, wherein an electronic actuator
is applied as the linear actuator.
3. The module as claimed in claim 1, wherein the damper acts upon
the push rod before the push rod reaches a final position
configured as a stop on the cylinder head.
4. The module as claimed in claim 1, wherein the damper dissipates
kinetic energy of the push rod as the push rod moves in the first
longitudinal direction.
5. The module as claimed in claim 1, wherein the damper dissipates
kinetic energy of the push rod as the push rod moves in a second
longitudinal direction, opposite the first longitudinal
direction.
6. The module as claimed in claim 1, wherein the damper is attached
to an end of the push rod.
7. The module as claimed in claim 1, further comprising the
cylinder head, and the damper is configured within the cylinder
head.
8. The module as claimed in claim 1, wherein a reverse position of
the push rod is accomplished in a second longitudinal direction by
a compression spring configured to be tensioned between the push
rod and the cylinder head.
9. The module as claimed in claim 8, wherein the damper and
compression spring are either combined in an assembly or are each
spatially separate.
10. The module as claimed in claim 1, wherein the damper is one of
either an elastic solid body, a gas damper, or a fluid damper.
11. The module as claimed in claim 1, wherein the actuating fingers
are leaf-like spring tongues.
12. An actuation system for a variable valve drive of an internal
combustion engine, comprising: a push rod configured to be mounted
longitudinally in a cylinder head of the internal combustion
engine, the push rod having at least one actuating finger
configured to actuate a coupling slide of at least one switchable
rocker arm; a linear actuator having an armature, the armature
configured to displace the push rod; and as the push rod is
displaced by the linear actuator, at least a portion of the kinetic
energy of the push rod is dissipated by a damper.
13. The actuation system of claim 12, wherein the damper is a
hydraulic clearance compensation element.
14. The actuation system of claim 12, further comprising the at
least one switchable rocker arm, wherein the coupling slide of the
at least one switchable rocker arm is arranged transversely to a
longitudinal side of the switchable rocker arm.
15. The actuation system of claim 14, wherein the at least one
switchable rocker arm includes a first and a second switchable
rocker arm, and the at least one actuating finger includes a first
and a second actuating finger, the first actuating finger arranged
to actuate the first switchable rocker arm and the second actuating
finger arranged to actuate the second switchable rocker arm.
16. The actuation system of claim 15, wherein displacement of the
push rod in a first longitudinal direction by the linear actuator
causes synchronous coupling or synchronous uncoupling of the first
and second switchable rocker arms.
17. The actuation system of claim 15, wherein the first and second
actuating fingers are leaf-like spring tongues that extend from the
push rod.
18. The actuation system of claim 12, wherein the damper dissipates
kinetic energy of the push rod as the push rod is displaced in a
first longitudinal direction by the linear actuator.
19. The actuation system of claim 12, further comprising a spring
that is arranged to move the push rod in a second longitudinal
direction.
20. The actuation system of claim 19, wherein the damper dissipated
kinetic energy of the push rod as it moves in the second
longitudinal direction.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. Section 119
of German Patent Application No. DE 2018 117 338.5 filed Jul. 18,
2018, the disclosure of which is incorporated herein by
reference.
TECHNICAL FIELD
[0002] This disclosure relates to a module of a variable valve
drive of an internal combustion engine. The module includes a push
rod mounted longitudinally in a cylinder head of the internal
combustion engine. The push rod is actuated by a linear actuator
that includes an armature that makes contact, at least indirectly,
with the push rod to displace it in a longitudinal direction. A
switchable rocker arm with a coupling slide arranged transversely
to the longitudinal extent or side of said rocker arm corresponds
to an actuating finger that extends from the push rod. The coupling
slide includes a slide part that projects laterally from the rocker
arm and can be acted upon by a free end of the actuating
finger.
BACKGROUND
[0003] Modules of this kind with a push rod acted upon by an
actuator, actuator fingers thereon, and rocker arms, are now also
referred to as electronic rocker modules or systems. One example of
this emerges from DE 10 2017 101 792. In this case, a series of
identically operating gas exchange valves in a series of cylinders
in an internal combustion engine in the cylinder head is each
assigned a rocker arm with an actuator on the front end, in this
case an electronic actuator. Two identically operating gas exchange
valves are provided for each cylinder. A reset of the push rod
takes place when the actuator is not energized through the force of
a servo means, in this case a compression spring.
[0004] The disadvantage of the aforementioned embodiment is that
the push rod emits structure-borne noise when one of its two final
positions is suddenly reached. These frequencies may lie within an
audible, and thus, within a comfort range. A "hard" stop of the
cylinder head (body edge) is a potential end point/reverse point
for the push rod in an actuator extension direction. In the return
direction thereof, either a counter-stop of this kind or a stop for
the armature of the actuator in said actuator is conceivable and
provided for. Depending on the embodiment of the actuator
armature/push rod assembly, said push rod may also become detached
from the armature when it is suddenly slowed down by a stop and
strike it while once again emitting noises.
[0005] The problem is that of creating a module of the
aforementioned kind which can be operated in a low-noise
manner.
SUMMARY
[0006] According to the disclosure, this problem is solved in that
the kinetic energy of the push rod, which may be a flat metal
sheet, a pipe or a solid cylinder, is dissipated at least partially
via a separate damper before it reaches its final position, at
least in a first longitudinal direction away from the linear
actuator. A damper according to one embodiment of the disclosure,
can be an elastic solid body (elastomer, plastic, rubber), a gas
damper, or a fluid damper.
[0007] In the simplest variant, a rubber piece, for example, is
therefore attached to the push rod on the free end face thereof,
through which the kinetic energy of the push rod is "abolished" or,
to be more precise, dissipated or converted, in the extension and
impact scenario brought about by the actuator, so that the push rod
reaches its final position comparatively "gently" and without
emitting audible noises. The damper may also lie on the
counter-contour of the cylinder head. Likewise, the other rearward
end point in the actuator may be provided with a mechanical damper
or this final position may likewise be "damped" by the
aforementioned measures on the push rod or the cylinder head. Where
necessary, dampers such as elastic solid bodies may also be
attached to each of the contours (push rod and cylinder head) in
one or both abutment cases.
[0008] An alternative would be a gas or fluid damper. Both dampers
may have a substantially progressive characteristic curve, so that
it is also possible for them to be permanently connected to the
push rod, at least in the extension direction thereof. A fluid
damper should also be understood to mean a leakage gap element, for
example, as is known from valve drive technology as a hydraulic
clearance compensation element which are also fitted into chain or
belt tensioners.
[0009] According to a further development of the disclosure, the
push rod, wherein a set of push rods is also always possible, is to
be acted upon in its reverse direction by a mechanical spring. At
least one helical compression spring, in particular, is envisaged
in this case, said helical compression spring being supported by
the cylinder head at one end. As an alternative to this, the push
rod may also be acted upon in the reverse position thereof via an
actuator, such as an electronic actuator.
[0010] Instead of the free end face of the push rod contacting the
damper, an arm which communicates with a damper of the cylinder
head or itself possesses a damper for what is then a "hard"
cylinder head contact may also project from the push rod.
[0011] It is also advantageous for the damping and compression
spring to be combined in a pre-mounted assembly. However, where
there are installation space problems, the separate application
thereof is however also a possibility.
[0012] The actuating fingers projecting from the push rod are
configured as leaf-like spring tongues according to one embodiment
of the disclosure, but they may also be "stiff" fingers under
certain circumstances.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In relation to the drawings:
[0014] FIG. 1 shows a first variant of a module with a damper and
spring existing separately from one another; and
[0015] FIG. 2 shows a partial view as previously mentioned, wherein
a damper and spring form a structural unit.
DETAILED DESCRIPTION
[0016] FIGS. 1, 2 show a module 1 of a variable valve drive of an
internal combustion engine. This module 1 is also referred to as an
electronic rocker module or system.
[0017] Module 1 comprises a push rod 3 mounted longitudinally in a
cylinder head 2 of the internal combustion engine. An actuating
finger 4 configured as a leaf-like spring tongue is suspended from
said push rod for each switchable rocker arm 7 to be actuated. The
push rod 3, as disclosed in FIG. 1, is preceded by a linear
actuator 5 configured as an electronic actuator (electronic
magnet). The push rod includes a face 19 on a right end that is
aligned with the linear actuator 5. An armature 6 of the linear
actuator 5 acts directly on the aforementioned face 19 to displace
the push rod 3 in the first longitudinal direction A.
[0018] Each actuating finger 4 cooperates with a switchable rocker
arm 7 as a further component of the module. The rocker arm 7
comprises in each case, although this need not be further dealt
with here, a box-like outer lever 15 which encloses an inner lever
16. On an underside (facing away from a camshaft) the rocker arm 7
has a support 17 for pivotable mounting on a support element on one
longitudinal end and a valve contact 18 on another longitudinal
end.
[0019] There projects laterally from each rocker arm 7 being
switched a coupling slide means 8 which therefore runs transversely
and which, in the simplest case, comprises precisely one slide part
9, wherein, however, two or three slide parts can be provided. The
slide part 9, as emerges from the two figures, is acted upon by a
free end 10 of its actuating finger 4. In this case, the actuating
fingers 4 in both figures are depicted out of contact with their
slide parts 9, which represents an unswitched state of the module
1. Where necessary, the aforementioned components may also be in
contact in this state.
[0020] So that all identically operating rocker arms 7 are
synchronously coupled (or, alternatively, uncoupled), the
electronic actuator 5 is energized, as a result of which the
armature 6 thereof displaces the push rod 3 in both figures, in
this case from right to left against the force of a compression
spring 13. The bendable actuating fingers 4 are pretensioned on
their slide parts 9, which slide parts 9 can then be suddenly
displaced when the cam base circle is passed through. According to
FIG. 1, the push rod 3 experiences a final travel limit at a "hard"
stop 12. Said stop is a simple body edge on the cylinder head
2.
[0021] According to FIG. 1, a damper 11 is provided on the module 1
which is spatially separate from the compression spring 13. This is
only depicted as a symbol here and, in the simplest case, comprises
a simple elastic solid body. From the push rod 3 which represents a
structural unit with the armature 6 here, there projects away an
arm 20 connected thereto which, when the armature 6 moves with the
push rod 3 in the first longitudinal direction A, comes into
contact with the damper 11 or is in contact from the very
beginning.
[0022] Through this embodiment, the push rod 3 experiences at its
one final position no sudden braking accompanied by noises and
increased wear. Instead, at least some of the kinetic energy of the
push rod 3 is converted in the damper 11 or dissipated by the
damper 11.
[0023] If the electronic actuator 5 is de-energized, a backwards
displacement of the push rod 3 takes place in a second longitudinal
direction B via the compression spring 13 with simultaneous
"removal" of the actuator fingers 4 from their slide parts 9. The
aforementioned fingers are acted upon in their respective rocker
arm 7 via spring means which are not labelled in the extension
direction (to the right in the case) and when the cam base circle
is passed through they are suddenly displaced outwards, as
depicted.
[0024] It is provided according to FIG. 2 for the damper 11 and
compression spring 13 to be combined in an assembly 14.
LIST OF REFERENCE CHARACTERS
[0025] 1 Module [0026] 2 Cylinder head [0027] 3 Push rod [0028] 4
Actuating finger [0029] 5 Linear actuator, electronic actuator
[0030] 6 Armature [0031] 7 Rocker arm [0032] 8 Coupling slide
[0033] 9 Slide part [0034] 10 End [0035] 11 Damper [0036] 12 Stop
[0037] 13 Compression spring [0038] 14 Assembly [0039] 15 Outer
lever [0040] 16 Inner lever [0041] 17 Support [0042] 18 Valve
contact [0043] 19 Face [0044] 20 Arm [0045] A first longitudinal
direction [0046] B second longitudinal direction
* * * * *