U.S. patent application number 14/256930 was filed with the patent office on 2014-08-14 for valve drive train device.
This patent application is currently assigned to DAIMLER AG. The applicant listed for this patent is DAIMLER AG. Invention is credited to Thomas STOLK, Alexander VON GAISBERG-HELFENBERG.
Application Number | 20140224199 14/256930 |
Document ID | / |
Family ID | 46845694 |
Filed Date | 2014-08-14 |
United States Patent
Application |
20140224199 |
Kind Code |
A1 |
STOLK; Thomas ; et
al. |
August 14, 2014 |
VALVE DRIVE TRAIN DEVICE
Abstract
In a valve drive train device for an internal combustion engine
of a motor vehicle including at least one cam element which is
mounted in a rotationally and axially displaceable manner and is
provided for actuating at least one gas exchange valve, and at
least one gate element which has at least one switch gate for valve
lift switching, the switch gate being provided for converting a
rotational movement of the cam element into an axial displacement
movement of the cam element, a support element is connected to the
cam element in a rotationally fixed manner and has at least one
limiting structure for limiting the axial displacement movement of
the cam element and the gate element is mounted in a rotationally
fixed manner but is axially movable for the valve lift
switching,
Inventors: |
STOLK; Thomas; (Kirchheim,
DE) ; VON GAISBERG-HELFENBERG; Alexander; (Beilstein,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DAIMLER AG |
Stuttgart |
|
DE |
|
|
Assignee: |
DAIMLER AG
Stuttgart
DE
|
Family ID: |
46845694 |
Appl. No.: |
14/256930 |
Filed: |
April 19, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/EP2012/003778 |
Sep 8, 2012 |
|
|
|
14256930 |
|
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Current U.S.
Class: |
123/90.15 |
Current CPC
Class: |
F01L 1/04 20130101; F01L
13/0036 20130101; F01L 1/053 20130101 |
Class at
Publication: |
123/90.15 |
International
Class: |
F01L 1/04 20060101
F01L001/04 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 21, 2011 |
DE |
102011116653.3 |
Claims
1. A valve drive train device for an internal combustion engine of
a motor vehicle, comprising a camshaft with at least one cam
element (10a, 11a, 12a; 10b) which is mounted in a rotationally and
axially displaceable manner and is provided for actuating at least
one gas exchange valve, and including a gate element (13a; 13b)
which has at least one switch gate (14a, 15a, 16a; 14b) for valve
lift switching, the switch gate being formed for converting a
rotational movement (17a) of the at least one cam element (10a,
11a, 12a; 10b) into an axial displacement movement (18a) of the at
least one cam element (10a, 11a, 12a; 10b), at least one support
element (19a 19b) which is connected to the at least one cam
element (10a, 11a, 12a; 10b) in a rotationally fixed manner and has
at least one limiting structure (20a, 21a; 20b) that is provided
for limiting the axial displacement movement (18a) of the at least
one cam element (10a, 11a, 12a; 10b), the gate element (13a; 13b)
being mounted in a rotationally fixed but axially movable manner
for controlling the valve lift switching.
2. The valve drive train device according to claim 1, wherein at
least one gate engagement element (22a, 23a, 24a; 22b) is provided
for an operative connection with the at least one switch gate (14a,
15a, 16a; 14b), which gate engagement element is situated so as to
be movable at least essentially perpendicularly with respect to a
main axis of rotation (25a) of the support element (19a; 19b).
3. The valve drive train device according to claim 2, wherein the
support element (19a; 19b) has at least one opening (26a, 27a; 26b)
for forming the limiting structure (20a, 21a 20b), and the gate
engagement element (22a, 23a, 24a; 22b) at least partially passes
through the at least one opening (26a, 27a; 26b).
4. The valve drive train device according to claim 3, wherein the
at least one opening (26a, 27a) has two axial opening ends (28a,
29a, 30a, 31a) and the gate engagement element (22a, 23a, 24a) for
limiting the axial displacement movement is provided to abut the
respective opening end (28a, 29a, 30a, 31a)
5. The valve drive train device according to claim 2, wherein the
gate engagement element (22a, 23a, 24a; 22b) is spring-biased so as
to be in continuous contact with the gate element (13a; 13b).
6. The valve drive train device according to claim 2, wherein the
at least one cam element (10a, 11a, 12a; 10b) forms a guide
structure (32a. 33a; 32b) for the gate engagement element (22a,
23a, 24a; 22b), the guide structure being provided for at least
partially accommodating the gate engagement element (22a, 23a, 24a;
22b).
7. The valve drive train device according to claim 2, wherein the
gate engagement element (22a, 23a, 24a; 22b) and the cam element
(10a, 11a, 12a; 10b) are connected to one another in a rotationally
fixed manner.
8. The valve drive train device according to claim 2, comprising at
least one guide element (34b) which is provided for at least
partially accommodating the at least one gate engagement element
(22b), and which is formed separately from the cam element (10b)
and at least partially extends through the at least one opening
(26b).
9. The valve drive train device according to claim 1, comprising an
actuator unit (35a) which is provided for displacing the gate
element (13a; 13b) only axially for the valve lift switching.
Description
[0001] This is a Continuation-In-Part application of pending
international patent application PCT/EP2012/003778 filed Sep. 8,
2012 and claiming the priority of German patent application 10 2011
116 653.3 filed Oct. 21, 2011.
BACKGROUND OF THE INVENTION
[0002] The invention relates to a valve drive train device for an
internal combustion engine of a motor vehicle.
[0003] A valve drive train device, in particular for an internal
combustion engine of a motor vehicle, is already known from DE 10
2009 037 270 B4. It includes two cam elements which are each
mounted on a camshaft in a rotationally and axially displaceable
manner, and are each provided for actuating two gas exchange
valves. Each cam element includes a gate element which has two
switch gates for valve lift switching, the switch gates being
provided for converting a rotational movement of the cam elements
into an axial displacement movement of the cam elements. Each cam
element further includes a support element which is connected to
the cam element in a rotationally fixed manner and has a limiting
element that is provided for limiting the axial displacement
movement of the respective cam element.
[0004] The principal object of the invention is to provide a
cost-effective valve drive train device with reliable
operation.
SUMMARY OF THE INVENTION
[0005] In a valve drive train device for an internal combustion
engine of a motor vehicle including at least one cam element which
is mounted in a rotationally and axially displaceable manner and is
provided for actuating at least one gas exchange valve, and at
least one gate element which has at least one switch gate for valve
lift switching, the switch gate being provided for converting a
rotational movement of the cam element into an axial displacement
movement of the cam element, a support element is connected to the
cam element in a rotationally fixed manner and has at least one
limiting structure for limiting the axial displacement movement of
the cam element and the gate element is mounted in a rotationally
fixed manner but is axially movable for the valve lift
switching.
[0006] The design of the valve drive train device, in particular of
the gate element and of the cam element, and also the mechanical
limiting means of the axial displacement path of the cam element,
can thus be structurally simplified, so that in particular
manufacturing costs can be reduced. A simple and cost-effective
valve drive train device may thus be provided. In addition, in a
valve drive train device which has at least two cam elements, an
independent axial displacement of the at least two cam elements can
be achieved in a particularly simple manner, whereby the axial
displacement may take place regardless of an instantaneous angular
position.
[0007] The term "cam element that is mounted in a rotationally and
axially displaceable manner" is understood in particular to mean a
cam element that is mounted so as to be rotatable and axially
displaceable with respect to a cylinder head or another stationary
component of the internal combustion engine. A "gate element that
is mounted in a rotationally fixed manner" is understood in
particular to mean a gate element that is mounted so as to be
rotationally fixed with respect to the cylinder head or the other
stationary component of the internal combustion engine. The term
"axial" is understood in particular to mean axial with respect to a
main axis of rotation of the cam element. The term "valve lift
switching" is understood in particular to mean a discrete switching
between at least two valve actuating cams with curves which provide
for a particular actuation of the at least one gas exchange valve.
A "gate element" is understood in particular to mean a component
which forms the switch gate and/or an element which forms the at
least one switch gate, and which is situated on the component in a
rotationally and axially fixed manner. A "switch gate" is
understood to mean a unit having at least one gate track which is
provided for converting a rotational movement into an axial
displacement force, A "gate track" is understood in particular to
mean a track for forced guiding of a gate engagement element at
least on one side, preferably on both sides. The gate track is
preferably designed in the form of a web, in the form of a slot,
and/or in the form of a groove. A "gate engagement element" is
understood in particular to mean an element which in at least one
operating state engages at least partially with the switch gate
and/or at least partially encloses the switch gate, and which is
therefore preferably in operative connection with the switch gate,
thus forcibly guiding the other way around the switch gate. The
gate engagement element is preferably designed in the form of a
shifting shoe which surrounds the web, in the form of a pin which
engages in the slot, and/or in the form of a pin which extends into
the groove. The term "connected in a rotationally fixed manner" is
understood in particular to mean a connection which transmits a
torque and/or a rotational motion unchanged. "Provided" is
understood in particular to mean specially designed, equipped,
and/or situated.
[0008] It is further proposed that the gate element is mounted in
an axially displaceable manner for the valve lift switching. The
valve lift switching may thus be achieved in a particularly simple
manner. The gate element for the valve lift switching is preferably
situated so as to be axially displaceable relative to the support
element axial. A "gate element that is mounted so as to be axially
displaceable" is understood in particular to mean a gate element
that is mounted so as to be axially displaceable with respect to
the cylinder head or the other stationary component of the internal
combustion engine.
[0009] Furthermore, it is further proposed that the valve drive
train device has at least one gate engagement element which is
provided for an operative connection with the at least one switch
gate, and which is situated so as to be movable at least
essentially perpendicularly with respect to a main axis of rotation
of the support element. Particularly advantageous valve lift
switching may thus be achieved. An "operative connection" is
understood in particular to mean a connection as the result of
which the gate engagement element is forcibly guided by the switch
gate, "Essentially" is understood in particular to mean a deviation
that is no more than 15 degrees, advantageously no more than 5
degrees, and particularly advantageously no more than 2
degrees.
[0010] It is further proposed that the support element has at least
one opening for providing the limiting element, and the gate
engagement element at least partially passes through the at least
one opening. Particularly simple limiting of the axial displacement
path of the at least one cam element may thus be provided. An
"opening" is understood in particular to mean a material void in
the support element that is delimited by a material of the support
element at least axially, and preferably in the circumferential
direction.
[0011] In particular, it is advantageous when the at least one
opening comprises two axial opening ends, and the gate engagement
element for the limiting is provided so that it lies against the
corresponding opening end, so that an additional element for
limiting the axial displacement movement is not necessary. An
"opening end" is understood in particular to mean an axial
delimitation of the opening by the material of the support element.
The two axial opening ends preferably define an opening width. The
two axial opening ends advantageously define a maximum axial
displacement path and thus a maximum axial displacement movement of
the at least one cam element. "Lying against" is understood in
particular to mean directly contacting.
[0012] Furthermore, it is advantageous when the gate engagement
element is designed for continuously contacting the gate element in
a spring-loaded manner, so that a secure operative connection
between the gate engagement element and the switch gate may be
achieved. "Spring-loaded" is understood in particular to mean that
the valve drive train device has at least one spring element which
acts on the gate element by means of an elastic force, the elastic
force preferably pointing in the direction of the gate element
and/or being oriented at least essentially perpendicularly with
respect to the main axis of rotation.
[0013] It is also advantageous when the at least one cam element
forms a guide for the gate engagement element, the guide being
provided for at least partially accommodating the gate engagement
element. The cam element may thus be axially displaced in a
particularly advantageous manner. A "cam element which forms a
guide for the gate engagement element" is understood in particular
to mean a cam element whose material defines an area in which the
gate engagement element is at least partially situated and may
preferably move. In this context, "define" is understood in
particular to mean surround and/or enclose.
[0014] In another embodiment according to the invention, the gate
engagement element and the cam element are connected to one another
in a rotationally fixed manner, as the result of which a
particularly advantageous valve drive train device may be
provided.
[0015] Furthermore, it is advantageous when the valve drive train
device has at least one guide element which is provided for at
least partially accommodating the at least one gate engagement
element, and which is formed separately from the cam element and at
least partially passes through the at least one opening. The
service life of the gate engagement element may be prolonged in
this way. A "guide element" is understood in particular to mean an
element which is at least partially situated in the guide for the
cam element, and which preferably at least partially directly
surrounds and/or encloses the gate engagement element.
[0016] In addition, it is proposed that the valve drive train
device has an actuator unit which is provided for displacing the
gate element only axially for the valve lift switching. A
complicated control, in particular of the at least one gate
element, may thus be dispensed with, so that a cost-effective and
simple control can be achieved. In addition, the actuator unit,
which must be provided solely for displacing the gate element, may
have a simple construction and thus, a cost-effective design.
[0017] In particular, it is advantageous when the gate engagement
element is in the form of a switching pin and/or stop pin, whereby
a particularly advantageous gate engagement element may be
provided.
[0018] In addition, an internal combustion engine having a valve
drive train device according to the invention is proposed, as the
result of which manufacturing costs for the internal combustion
engine may be reduced.
[0019] The invention will become more readily apparent from the
following description of two exemplary embodiments with reference
to the accompanying drawings. The drawings, the description, and
the claims contain numerous features in combination. Those skilled
in the art may also advantageously consider the features
individually and combine them into further meaningful
combinations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows a valve drive train device for an internal
combustion engine of a motor vehicle,
[0021] FIG. 2 shows an enlarged detail of the valve drive train
device, and
[0022] FIG. 3 shows an enlarged detail of a valve drive train
device having an alternative design.
DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0023] FIGS. 1 and 2 show a valve drive train device for an
internal combustion engine of a motor vehicle, an enlarged detail
of the valve drive train device being illustrated in FIG. 2. The
valve drive train device is designed as a motor vehicle valve drive
train device. The motor vehicle is designed as a passenger
vehicle
[0024] The valve drive train device includes three cam elements
10a, 11a, 12a, each of which has at least one cam 36a for actuating
a gas exchange valve. The cams 36a in each case include two
directly adjacent partial cams 37a, 38a which have different cam
curvatures. The partial cams 37a, 38a may be designed, for example,
for a full lift, a partial lift, or a zero lift. For simplicity,
only the one cam 36a is provided with a reference numeral in FIG.
1.
[0025] The cam elements 10a, 11a, 12a are rotationally and axially
displaceably mounted in a cylinder head of the internal combustion
engine, not illustrated in greater detail. A cam follower, not
illustrated in greater detail, may be displaced from one of the
partial cams 37a, 38a to the other of the partial cams 37a, 38a by
an axial displacement movement 18a of the cam elements 10a, 11a,
12a with respect to the gas exchange valves. Corresponding to a
valve lift for which the appropriate partial cam 37a, 38a is
provided, the corresponding gas exchange valve is then acted on
with a full lift, a partial lift, or a zero lift. The cam elements
10a, 11a, 12a have discrete switch positions that are associated
with the individual partial cams 37a, 38a.
[0026] In principle, the cam elements 10a, 11a, 12a may be provided
for an inlet side or an outlet side. The internal combustion engine
for which the illustrated valve drive train device is provided
includes multiple gas exchange valves per cylinder in each case on
the inlet side and/or on the outlet side. The illustrated cam
elements 10a, 11a, 12a are each provided for actuating two gas
exchange valves which are associated with the same cylinder. The
cams 36a of the respective cam elements 10a, 11a, 12a are each
provided for the gas exchange valves of a single cylinder; i.e., in
the installed state, each of the cam elements 10a, 11a, 12a is
associated with exactly one cylinder of the internal combustion
engine and actuates the gas exchange valves situated on the inlet
side or the outlet side of the cylinder. The number of cam elements
10a, 11a, 12a thus corresponds to the number of cylinders of the
internal combustion engine. The individual cam elements 10a, 11a,
12a are connected to one another in a rotationally fixed but
axially displaceable manner with respect to one another, and form a
camshaft of the internal combustion engine.
[0027] The valve drive train device has a support element 19a for
supporting the cam elements 10a, 11a, 12a, The cam elements 10a,
11a, 12a and the support element 19a are connected to one another
in a rotationally fixed manner. The cam elements 10a, 11a, 12a are
supported on the support element 19a in an axially displaceable
manner, and are situated on the support element 19a so as to be
rotationally fixed but axially displaceable. The support element
19a is situated inside the cam elements 10a, 11a, 12a, and passes
through the cam elements 10a, 11a, 12a. The cam elements 10a, 11a,
12a each have a hollow design and enclose the support element 19a.
The cam elements 10a, 11a, 12a and the support element, 19a are
situated coaxially with respect to one another. The cam elements
10a, 11a, 12a and the support element 19a have a main axis of
rotation 25a about which they rotate during operation of the
internal combustion engine. The support element 19a is designed as
a carrier shaft and has a hollow design. The support element 19a
has a tubular design.
[0028] In order to axially displace the cam elements 10a, 11a, 12a,
the valve drive train device includes a valve lift switching unit
39a. The valve lift switching unit 39a has a gate element 13a which
is mounted in a rotationally fixed manner. The gate element 13a is
mounted so as to be axially displaceable with respect to a valve
lift switching relative to the support element 19a The gate element
is situated so as to be rotationally fixed but axially displaceable
with respect to the valve lift switching relative to the support
element 19a. The gate element 13a has three switch gates 14a, 15a,
16a for the individual cam elements 10a, 11a, 12a, respectively,
for the valve lift switching, and thus for axially displacing the
cam elements 10a, 11a, 12a. The switch gates 14a, 15a, 16a convert
a rotational movement 17a of the cam elements 10a, 11a, 12a,
respectively, into an axial displacement movement 18a of the cam
elements 10a, 11a, 12a. For the valve lift switching, the gate
element 13a is mounted so as to be axially displaceable relative to
the support element 19a and the cam elements 10a, 11a, 12a, but is
rotationally fixed. The gate element 13a is for the most part
radially situated within the support element 19a, and extends
through the support element 19a. The gate element 13a is situated
inside the cam elements 10a, 11a, 12a. The support element 19a and
the cam elements 10a, 11a, 12a rotate about the gate element 13a
during operation of the internal combustion engine, and enclose the
gate element 13a.
[0029] For limiting the axial displacement movement 18a of the cam
elements 10a, 11a, 12a, the support element 19a has three limiting
elements, only two limiting elements 20a, 21a being visible on
account of the angular position of the support element 19a in FIG.
1. The limiting element which is not visible is concealed by the
gate element 13a. A limiting element 20a, 21a is associated in each
case with a cam element 10a, 11a, 12a; i.e., a limiting element
20a, 21a in each case limits the axial displacement movement 18a of
a respective corresponding cam element 10a, 11a, 12a. The limiting
element 20a limits the axial displacement movement 18a of the cam
element 10a, the limiting element 21a limits the axial displacement
movement 18a of the cam element 11a, and the limiting element which
is not visible limits the axial displacement movement 18a of the
cam element 12a.
[0030] The support element 19a has openings 26a, 27a for providing
the limiting elements 20a, 21a, respectively Each opening 26a, 27a
provides a limiting element 20a, 21a, respectively. The openings
26a, 27a have two axial opening ends 28a, 29a and 30a, 31a,
respectively, whose respective axial distance from one another
limits a maximum displacement movement 18a of the corresponding cam
element 10a, 11a, 12a. The axial distance between the opening ends
28a, 29a and 30a, 31a, respectively, corresponds to the width of
the respective opening 26a. 27a. The opening ends 28a, 29a, 30a,
31a are in each case formed by a material of the support element
19a. The openings 26a, 27a are formed by an absence of material of
the support element 19a, and are produced, for example, by
drilling, milling, or the like. The openings 26a, 27a are situated
at a distance from one another in an axial direction and in the
circumferential direction. The openings are provided in the support
element 19a in an offset manner with respect to an axial direction
and the circumferential direction.
[0031] In addition, the valve lift switching unit 39a includes gate
engagement elements 22a, 23a, 24a which are provided for an
operative connection with the switch gates 14a, 15a, 16a,
respectively, and which are connected to the cam elements 10a, 11a,
12a, respectively. The gate engagement elements 22a, 23a, 24a are
connected to a cam element 10a, 11a, 12a, respectively, in a
rotationally fixed manner with respect to the main axis of rotation
25a and are connected so as to be rotatable about the main axis of
extension of the gate engagement elements 22a, 23a, 24a
perpendicular to the main axis of rotation 25a The gate engagement
element 22a is associated with the cam element 10a, the gate
engagement element 23a is associated with the cam element 11a, and
the gate engagement element 24a is associated with the cam element
12a, The gate engagement element 24a is concealed by the gate
element 13a on account of an angular position of the cam element
12a in FIG. 1, for which reason the gate engagement element 24a is
illustrated by a dashed line. The number of switch gates 14a, 15a,
16a and the number of gate engagement elements 22a, 23a, 24a are
equal to the number of cam elements 10a, 11a, 12a. Each of the cam
elements 10a, 11a, 12a has exactly one of the gate engagement
elements 22a, 23a, 24a. In turn, exactly one of the switch gates
14a, 15a, 16a is associated with the gate engagement elements 22a,
23a, 24a, respectively, and thus also with the cam elements 10a,
11a 12a, respectively. In principle, a design having fewer or more
than the three illustrated cam elements 10a, 11a, 12a is
conceivable, for example for an in-line engine having four, five,
or six cylinders and a corresponding number of cam elements.
[0032] The switch gate 14a and the gate engagement element 22a
which are in operative connection, the switch gate 15a and the gate
engagement element 23a which are in operative connection, and the
switch gate 16a and the gate engagement element 24a which are in
operative connection are in each case provided for converting the
rotational movement 17a of the corresponding cam element 10a, 11a,
12a about its main axis of rotation 25a into the axial displacement
movement 18a along the main axis of rotation 25a. The switch gates
14a, 15a, 16a in each case include two gate tracks for displacing
the cam elements 10a, 11a, 12a, respectively. The first gate track
is provided for displacing the cam element 10a, 11a, 12a, which is
associated with the corresponding switch gate 14a, 15a, 16a, along
a first switching direction from the first switch position into the
second switch position. The second gate track is provided for
displacing the cam element 10a, 11a, 12a, which is associated with
the corresponding switch gate 14a, 15a, 16a, along a second
switching direction from the second switch position into the first
switch position. The switch gates 14a, 15a, 16a each have the same
number of gate tracks.
[0033] The gate tracks are axially inclined, at least in partial
areas. When one of the gate engagement elements 22a, 23a, 24a is
meshed with the corresponding switch gate 14a, 15a, 16a, a rotation
of the cam element 10a, 11a, 12a about the main axis of rotation
25a causes a force to act on the cam element 10a, 11a, 12a which
results in displacement of the cam element 10a, 11a, 12a along the
main axis of rotation 25a. The gate tracks in connection with the
gate engagement elements 22a, 23a, 24a convert a rotational
movement of the cam elements into a linear movement. In areas in
which the gate element 13a has the switch gates 14a, 15a, 16a, the
gate element 13a has an outer cylindrical lateral surface 40a into
which the switch gates 14a, 15a, 16a are formed, The gate tracks
thus face outwardly. The gate tracks are designed as grooves which
are cut into the gate element 13a. The gate element 13a is situated
in a rotationally fixed but axially displaceable manner with
respect to the cylinder head.
[0034] The gate element 13a forms the switch gates 14a, 15a, 16a,
and is designed as a switch gate carrier. The gate element 13a is
designed as a gate shaft The gate element 13a, which forms the
switch gates 14a, 15a, 16a together with the gate tracks, is a
one-piece design. The gate element 13a forms the switch gates 14a,
15a, 16a for all the coaxially situated cam elements 10a, 11a, 12a.
The gate element 13a is a cast and/or forged part, and is formed
from a single blank. The switch gates 14a, 15a, 16a are
subsequently introduced using a metal cutting process, in
particular milling. In principle, the gate element 13a may also be
composed of a base shaft and a separate element which forms the
switch gates 14a, 15a, 16a and which is situated on the base shaft
in a rotationally and displaceably fixed manner. Of course, it is
also conceivable for each switch gate 14a, 15a, 16a to be formed by
a separate element, which in each case is situated on the base
shaft in a rotationally and displaceably fixed manner.
[0035] For establishing the operative connection of the gate
engagement elements 22a, 23a, 24a with the respective switch gates
14a, 15a, 16a, the gate engagement elements 22a, 23a, 24a extend
through a respective opening 26a, 27a. The gate engagement element
22a extends through the opening 26a, thus contacting the gate
element 13a. The gate engagement element 23a extends through the
opening 27a, thus contacting the gate element 13a. The gate
engagement element 24a extends through the opening which is not
visible, thus contacting the gate element 13a, The gate engagement
elements 22a, 23a, 24a are in each case situated between the
corresponding opening ends 28a, 29a, 30a, 31a in the axial
direction.
[0036] For limiting the axial displacement movement 18a of the cam
elements 10a, 11a, 12a, the gate engagement elements 22a, 23a, 24a,
respectively, are provided for resting directly against the
corresponding opening end 28a, 29a, 30a, 31a. To prevent the
maximum displacement movement 18a from being exceeded, the gate
engagement elements 22a, 23a, 24a strike against the corresponding
opening end 28a, 29a, 30a, 31a, depending on the switching
direction, which prevents a further axial displacement movement 18a
of the corresponding cam element 10a, 11a, 12a into the switching
direction and thus limits the axial displacement movement 18a, The
gate engagement elements 22a, 23a, 24a are in the form of switch
pins and stop pins which are guided on both sides in the gate
tracks of the switch gates 14a, 15a, 16a for valve lift switching
and for limiting the axial displacement movement 18a of the cam
elements 10a, 11a, 12a toward the corresponding opening end 28a,
29a, 30a, 31a and thus toward the support element 19a.
[0037] The gate engagement; elements 22a, 23a, 24a are situated on
an inner periphery 41a of the cam elements 10a, 11a, 12a,
respectively, and are each situated so as to be movable
perpendicularly with respect to the main axis of rotation 25a of
the support element 19a. The gate engagement elements 22a, 23a, 24a
are situated so as to he movable relative to the cam elements 10a,
11a, 12a, respectively, and are movable, relative to the support
element 19a, perpendicularly with respect to the main axis of
rotation 25a of the support element 19a. The gate engagement
elements 22a, 23a, 24a are connected in a rotationally fixed manner
to cam elements 10a, 11a, 12a, respectively, with respect to the
main axis of rotation 25, and rotatably about the main axis of
extension of the gate engagement elements 22a, 23a, 24a
perpendicular to the main axis of rotation 25, but may be displaced
along their main extension, which extends in the radial direction
with respect to the main axis of rotation 25a. The gate engagement
elements have one degree of freedom of motion in the corresponding
cam element 10a, 11a, 12a which is situated perpendicularly with
respect to the main axis of rotation 25a.
[0038] For accommodating the gate engagement elements 22a, 23a,
24a, the cam elements 10a, 11a, 12a, respectively, form a guide
32a, 33a for the corresponding gate engagement element 22a, 23a,
24a. The guide for the gate engagement element 24a formed by the
cam element 12a is not visible, since it is concealed by the
support element 19a and the gate element 13a on account of the
angular position of the cam element 12a. The guides 32a, 33a are
formed by a blind bore in the corresponding cam element 10a, 11a,
12a. The guides 32a, 33a are in each case open toward the gate
element 13a, and are formed by a material of the corresponding cam
element 10a, 11a, 12a. For achieving the movable arrangement of the
gate engagement elements 22a, 23a, 24a and thus for providing the
degree of freedom of motion of the gate engagement elements 22a,
23a, 24a, the guides 32a, 33a in each case have a main extension
that is oriented perpendicularly with respect to the main axis of
rotation 25a. The main extension of the gate engagement elements
22a, 23a, 24a and the main extension of the guides 32a, 33a are
radial. The material of the cam elements 10a, 11a, 12a in each case
directly surrounds the corresponding gate engagement element 22a,
23a, 24a. When a gate engagement element 22a, 23a, 24a rests
against an opening end 28a, 29a, 30a, 31a, the gate engagement
element 22a, 23a, 24a transmits a force from the support element
19a directly to the cam element 10a, 11a, 12a, thus preventing
further axial displacement movement 18a. For limiting the axial
displacement movement 18a, the gate engagement elements 22a, 23a,
24a are in each case provided for directly contacting the support
element 19a and the corresponding cam element 10a, 11a, 12a. The
axial displacement movement 18a of the rotating cam element 10a,
11a, 12a is limited by the rotating gate engagement element 22a,
23a, 24a and the rotating support element 19a.
[0039] To bring the gate engagement elements 22a, 23a, 24a into
engagement with the corresponding switch gate 14a, 15a, 15a, the
valve drive train device includes a plurality of actuating
mechanisms 42a, 43a which are provided for automatically (i.e.,
without control by an actuator provided specifically for this
purpose) bringing their associated gate engagement element 22a,
23a, respectively, into operative connection with the corresponding
switch gate 14a, 15a. An actuating mechanism for the gate
engagement element 24a is not visible in the figures. The actuating
mechanisms 42a, 43a are situated in the corresponding guide 32a,
33a for the corresponding cam element 10a, 11a, 12a.
[0040] The gate engagement elements 22a, 23a, 24a each are
spring-loaded for continuously contacting the gate element 13a. The
actuating mechanisms 42a, 43a have a spring element 44a, 45a,
respectively, which is supported on the associated cam element 10a,
11a and which exerts a force that is directed toward the respective
gate engagement element 22a, 23a in the direction of the gate
element 13a. The spring elements 44a, 45a are situated in the
corresponding guide 32a, 33a, respectively. One end of each spring
element 44a, 45a rests against the corresponding cam element 10a,
11a, 12a, and the other end of each spring element 44a, 45a rests
against the corresponding gate engagement element 22a, 23a, 24a.
The elastic force is oriented parallel to the main extension of the
guides 32a, 33a and parallel to the main extension of the gate
engagement elements 22e, 23a, 24a. The spring elements 44a, 45a
press the gate engagement elements 22a 23a radially inwardly
against the gate element 13a. In principle, the gate engagement
elements 22a, 23a, 24a may be switchable, preferably by means of a
control and regulation unit, in order, for example, to selectively
axially displace only certain cam elements 10a, 11a, 12a, for
example to switch off at least one cylinder. Due to the switchable
design of the gate engagement elements 22a, 23a, 24a, the
contacting of the gate element 13a by the gate engagement elements
22a, 23a, 24a may be selectively established. In the switchable
design of the gate engagement elements 22a, 23a, 24a, the gate
element 13a may also be mounted in an axially displaceably fixed
manner, and thus in a rotationally and displaceably fixed
manner.
[0041] The gate element 13a is situated within the cam elements
13a, 11a, 12a so as to be axially displaceable in order to
selectively bring the gate engagement elements 22a, 23a, 24a,
respectively, into engagement with the corresponding gate track for
the first switching direction or into engagement with the gate
track for the second switching direction. For the valve lift
switching, the valve lift switching unit 39a has an actuator unit
35a which only axially displaces the gate element 13a for the valve
lift switching. The actuator unit 35a includes an individual
control actuator 46a which axially displaces the gate element 13a
for the valve lift switching. The gate element 13a has two switch
positions, which correspond to the switch positions of the cam
elements 10a, 11a, 12a.
[0042] The valve drive train device also has a drive wheel 47a
which drives the cam elements 10a, 11a, 12a and the support element
19a. The drive wheel 47a provides a drive connection of the cam
elements 10a, 11a, 12a and the support element 19a to a crankshaft
of the internal combustion engine, not illustrated in greater
detail. The drive wheel 47a is designed as a crankshaft sprocket,
and provides a drive connection of the cam elements 10a, 11a, 12a
and the support element 19a to the crankshaft by means of a chain,
not illustrated in greater detail. The drive wheel 47a is a chain
wheel. The support element 19a and the cam element 10a are
connected to the drive wheel 47a in a rotationally fixed manner.
The drive wheel 47a and the support element 19a are formed together
in one piece. In principle, the drive wheel 47a may also be
designed as a toothed belt wheel which provides a drive connection
of the cam elements 10a, 11a, 12a and the support element 19a to
the crankshaft by means of a toothed belt, not illustrated in
greater detail. Of course, it is also conceivable for the cam
elements 10a, 11a, 12a to be in drive connection with the drive
wheel 47a solely via a rotationally fixed connection to the support
element 19a.
[0043] The valve drive train device has bearings 48a, 49a, 50a, 51a
for supporting the drive wheel 47a, the cam elements 10a, 11a, 12a,
and the support element 19a. The bearings 48a, 49a, 50a, 51a
support the drive wheel 47a, the cam elements 10a, 11a, 12a, and
the support element 19a on the cylinder head. The bearings are
situated at an axial distance from one another.
[0044] If the gate element 13a, starting from an operating state in
which all cam elements 10a, 11a, 12a of the valve drive train
device are switched into the first switch position, is switched
from its first switch position into the second switch position, the
gate engagement elements 22a, 23a, 24a of all cam elements 10a,
11a, 12a are situated in axial overlap with a start of the
respective gate tracks, which are provided for switching the cam
elements 10a, 11a, 12a from the first switch position into the
second switch position. During a rotational movement 17a of the cam
elements 10a, 11a, 12a, the gate engagement elements 22a, 23a, 24a
therefore engage with the corresponding gate track as soon as a
rotational angle of the corresponding cam element 10a, 11a, 12a has
passed, i.e., when the start of the gate track in the radial
direction is aligned with the gate engagement element 22a, 23a,
24a.
[0045] After the valve lift switching, and thus after the
corresponding displacement of the cam elements 10a, 11a, 12a, the
gate engagement elements 22a, 23a, 24a of all cam elements 10a,
11a, 12a, respectively, are situated in axial overlap with an end
of the respective gate tracks, which are provided for switching the
cam elements 10a, 11a, 12a from the first switch position into the
second switch position. As long as such an axial position of the
gate element 13a remains constant and therefore no axial
displacement of the gate element 13a takes place, the gate
engagement elements 22a, 23a, 24a of all cam elements 10a, 11a, 12a
are situated in axial overlap with the end of the respective gate
track, thus preventing an axial displacement movement 18a. If the
gate element 13a, starting from an operating state in which all cam
elements 10a, 11a, 12a of the valve drive train device are switched
into the second switch position, is switched from its second switch
position into the first switch position, the gate engagement
elements 22a, 23a, 24a of all cam elements 10a, 11a, 12a are
situated in axial overlap with a start of the respective gate
track, which are provided for switching the cam elements 10a, 11a,
12a from the second switch position into the first switch position,
thus displacing the cam elements 10a, 11a, 12a until the cam
elements 10a, 11a, 12a are situated in axial overlap with one end
of the respective gate tracks, which are provided for switching the
cam elements 10a, 11a, 12a from the second switch position into the
first switch position.
[0046] An angular range over which the particular cam element 10a,
11a, 12a is displaced is defined by a phase position of the
respective gate engagement element 22a, 23a, 24a and a phase
position of the associated switch gate 14a, 15a, 16a, Since each
cam element 10a, 11a, 12a has one of the gate engagement elements
22a, 23a, 24a and is associated with one of the switch gates 14a,
15a, 16a, each of the cam elements 10a, 11a, 12a may be displaced
at a separate individual rotational angle. Each cam element 10a,
11a, 12a thus has an individual angular sensitivity.
[0047] As soon as the gate element 13a has been displaced by means
of the control actuator 46a, all cam elements 10a, 11a, 12a, which
are coupled to the gate element 13a, are switched. The individual
cam elements 10a, 11a, 12a are automatically, independently
displaced according to the switch position of the gate element 13a
as soon as the particular cam element 10a, 11a, 12a has the
corresponding rotational angle at which a displacement of the cam
element 10a, 11a, 12a is initiated.
[0048] FIG. 3 shows a second exemplary embodiment of the invention.
The following description is limited essentially to the differences
between the exemplary embodiments, wherein reference may be made to
the description of the other exemplary embodiment, in particular in
FIGS. 1 and 2, for components, features, and functions which remain
the same. For distinguishing the exemplary embodiments, the letter
"a" in the reference numerals for the exemplary embodiment in FIGS.
1 and 2 is replaced by the letter "b" in the reference numerals for
the exemplary embodiment in FIG. 3. With regard to components
denoted in the same way, in particular components having the same
reference numerals, reference may basically also be made to the
drawings and/or the description of the first exemplary embodiment,
in particular in FIGS. 1 and 2.
[0049] FIG. 3 illustrates an enlarged detail of an alternative
design of a valve drive train device for an internal combustion
engine of a motor vehicle. In contrast to the preceding exemplary
embodiment, the valve drive train device additionally has a guide
element 34b which accommodates a gate engagement element 22b that
is provided for the operative connection with a switch gate 14b,
The guide element 34b is separate from a cam element 10b, and
partially passes through an opening 26b, which provides a limiting
element 20b of an axial displacement movement. The guide element is
partially situated within the cam element 10b. The guide element
34b is situated in a guide 32b, and is inserted into the guide 32b.
The guide element 34b is connected to the cam element 10b in a
rotationally fixed manner.
[0050] The guide element 34b extends radially inwardly from the cam
element 10b and thus in the direction of a gate element 13b. The
guide element 34b prevents the gate engagement element 22b from
directly striking an opening end 28b and an opening end 29b. For
the limiting, the guide element 34b rests against the corresponding
opening end 28b, 29b of a support element 19b. The guide element
34b directly surrounds the gate engagement element 22b and a spring
element 44b. The spring element 44b at one end rests against the
guide element 34b, and at the other end rests against the gate
engagement element 22b. The spring element is supported on the cam
element 10b by means of the guide element 34b. The cam element 10b
indirectly surrounds the gate engagement element 22b. The guide
element 34b is situated between a material of the cam element 10b
and the gate engagement element 22b, The guide element is provided
for limiting the axial displacement movement and for directly
contacting the support element 19b and the cam element lob. The
guide element prevents direct contact between the gate engagement
element 22b and the support element 19b, as well as direct contact
between the gate engagement element 22b and the cam element 10b.
The guide element 34b is designed as a guide sleeve. The gate
engagement element 22b is in the form of a switching pin.
LISTING OF REFERENCE NUMERALS
[0051] 10 Cam element [0052] 11 Cam element [0053] 12 Cam element
[0054] 13 Gate element [0055] 14 Switch gate [0056] 15 Switch gate
[0057] 16 Switch gate [0058] 17 Rotational movement [0059] 18
Displacement movement [0060] 19 Support element [0061] 20 Limiting
element [0062] 21 Limiting element [0063] 22 Gate engagement
element [0064] 23 Gate engagement element [0065] 24 Gate engagement
element [0066] 25 Main axis of rotation [0067] 26 Opening [0068] 27
Opening [0069] 28 Opening end [0070] 29 Opening end [0071] 30
Opening end [0072] 31 Opening end [0073] 32 Guide [0074] 33 Guide
[0075] 34 Guide element [0076] 35 Actuator unit [0077] 36 Cam
[0078] 37 Partial cam [0079] 38 Partial cam [0080] 39 Valve lift
switching unit [0081] 40 Lateral surface [0082] 41 Inner periphery
[0083] 42 Actuating mechanism [0084] 43 Actuating mechanism [0085]
44 Spring element [0086] 45 Spring element [0087] 46 Control
actuator [0088] 47 Drive wheel [0089] 48 Bearing [0090] 49 Bearing
[0091] 50 Bearing [0092] 51 Bearing
* * * * *