DE102021109489A1 - Rocker arm assembly for a valve train of an internal combustion engine and method for operating a rocker arm assembly - Google Patents

Abstract

The invention relates to a rocker arm arrangement for a valve drive of an internal combustion engine, with at least one switchable rocker arm (1) arranged pivotably on a rocker arm axis (3), characterized in that the rocker arm (1) has at least three lever arms (4, 5, 6) on the cam side, each for pick-off of a valve control cam from a camshaft (11) of the internal combustion engine and at least one lever arm (7) on the valve side for actuating at least one gas exchange valve (12, 13) of the internal combustion engine, the lever arms (4, 5, 6, 7) being pivotable relative to one another on the common Arranged rocker arm axis (3) and for switching the rocker arm (1), the cam-side lever arms (4, 5, 6) can be coupled independently of one another with the valve-side lever arm (7) for valve actuation. The invention also relates to a method for operating such a rocker arm arrangement.

Description

The invention relates to a rocker arm arrangement for a valve train of an internal combustion engine and a method for operating such a rocker arm arrangement.

Out of DE 10 2017 129 720 A1 a switchable rocker arm arrangement with at least one rocker arm is known, which is mounted on a machine-fixed rocker arm axis and has a cam arm connected to a camshaft and a valve arm connected to at least one gas exchange valve of a reciprocating internal combustion engine.

The invention is therefore based on the object of proposing a rocker arm arrangement and a method of the aforementioned type which enable valve control which is simple in design and improved in operation.

The object is achieved by the features of claim 1 and alternatively by the features of claim 10. Further advantageous and claimed configurations result from the respective dependent claims, the description and the drawings.

Thus, a rocker arm arrangement for a valve train of an internal combustion engine is proposed with at least one switchable rocker arm arranged pivotably on a rocker arm axis, which has at least three lever arms on the cam side, each for picking up a valve control curve from a camshaft of the internal combustion engine, and at least one lever arm on the valve side for actuating at least one gas exchange valve of the internal combustion engine. Since the lever arms can be pivoted to one another on the common rocker arm axis and the cam-side lever arms can be coupled independently of one another to the valve-side lever arm for valve actuation in order to shift the rocker arm, individual actuation of the cam-side lever arms is possible. As a result, at least three different valve control curves for controlling one or more gas exchange valves can be selectively transmitted. As a result, a rocker arm arrangement that can be selectively switched at least in three stages can be implemented and allows improved variable valve control of the internal combustion engine.

In a preferred embodiment of the invention, a first cam-side lever arm for picking up a first valve cam is in contact with at least one first cam of the camshaft and a second cam-side lever arm for picking up a second valve cam is in contact with at least a second cam of the camshaft, and a third cam-side lever arm for Pick-off of a third valve control curve in contact with at least a third cam of the camshaft. In this way, three different valve control curves can be transmitted independently of one another or in any combination to control one or more gas exchange valves of the internal combustion engine on the rocker arm.

Preferably, the first cam is designed to transmit a full valve lift and the second and third cams are each designed to transmit a full valve lift and a partial valve lift connected downstream of this phase-shifted. In this way, a full valve lift or a full valve lift together with a respective first or second additional valve lift can be transmitted independently of one another by a single actuation of a cam-side lever arm. For example, for thermodynamic optimization of the internal combustion engine, a small additional valve lift can be transferred as a partial valve lift to the outlet gas exchange valves, in particular for exhaust gas recirculation, or to the inlet gas exchange valves, in particular to carry out a so-called Miller lift. In addition, independently of this, an additional valve lift can be transmitted as an engine braking lift to the inlet or outlet gas exchange valves.

In a further preferred embodiment of the invention, the pickup of the cam-side lever arms from the camshaft and the valve actuation of the valve-side lever arm are arranged on opposite sides of the rocker arm axis. This enables a simple arrangement of one or more switchable rocker arms for actuating a plurality of gas exchange valves of at least one cylinder of the internal combustion engine driven by a camshaft.

A simple and space-saving integration of the lever arms can be achieved if the lever arm on the valve side is arranged between two lever arms on the cam side, wherein in addition to one of the aforementioned lever arms on the cam side, another lever arm on the cam side is arranged on the rocker arm axis, forming an outer side of the rocker arm.

It is advantageously possible to arrange at least one actuator on the outside of the rocker arm. An axially continuous recess is preferably provided on the cam-side lever arm forming the outside of the rocker arm, in which the actuator for switching an inner cam-side lever arm engages in direct actuating contact. The actuator is preferably arranged at least partially in the recess in a space-saving manner. It is also advantageous here if the outside of the rocker arm forming cam-side lever arm has a small pivoting angle during operation.

In a further preferred embodiment of the invention, a coupling means is assigned to each cam-side lever arm for coupling to the respective valve-side lever arm. Preferably, the coupling means can each be switched independently of one another in direct actuating contact by an associated electrical actuator, which makes it possible to actuate each cam-side lever individually in a simple manner. The direct switching contact ensures high switching dynamics with low switching forces with reduced component tolerance requirements with few components. In addition, electrical actuation, in particular with electrical lifting magnets, makes it possible to avoid hydraulic or mechanical actuators that require a lot of space and are expensive. At the same time, simple individual electrical control of the coupling means is made possible by energizing or de-energizing the respective actuator.

A distribution of the load on the coupling means and the rocker arm that is as uniform as possible can be achieved if the coupling means are each arranged at the same or at least approximately the same radial distance from the axis of the rocker arm.

To actuate at least one further gas exchange valve of the internal combustion engine, at least one second rocker arm, which can be switched independently of the first rocker arm, can be arranged on the common rocker arm axis so that it can pivot relative to the first rocker arm. The first rocker arm is preferably in valve contact with at least one outlet gas exchange valve and the second rocker arm is in valve contact with at least one inlet gas exchange valve of the internal combustion engine. In this way, a plurality of gas exchange valves, in particular the inlet and outlet gas exchange valves, of a cylinder of the internal combustion engine can be switched independently of one another by means of two rocker arms arranged on a rocker arm axis and drivable by a camshaft. Cylinder deactivation is also possible. In this way, individual actuation for each cylinder of the internal combustion engine can be achieved.

It is also conceivable, conversely, to arrange the first rocker arm in valve contact with at least one inlet gas exchange valve and the second rocker arm in valve contact with at least one outlet gas exchange valve of the internal combustion engine. It is also possible, depending on the space available, to configure the second rocker arm to be switchable in the same way as the first rocker arm, in order to enable both the outlet gas exchange valves and the inlet gas exchange valves to be activated in the manner described above.

In a further preferred embodiment of the invention, the second rocker arm has at least one further lever arm on the cam side for picking up at least one further valve control curve from the camshaft and at least one further lever arm on the valve side for actuating at least one further gas exchange valve of the internal combustion engine, the lever arms being pivotable relative to one another on the common rocker arm axis arranged and can be coupled together for switching the rocker arm. The further lever arm on the cam side is preferably in contact with a further cam of the camshaft in order to transmit a full valve lift.

As part of a development of the invention, it is provided that the actuators are at least partially integrated in a carrier connected to the rocker arm axis. As a result, the rocker arm arrangement can be easily installed as a preassembled structural unit on the cylinder head of the internal combustion engine. In a further embodiment, the carrier for accommodating the actuators has at least one first carrier housing arranged axially between the first and second rocker arm and at least one second carrier housing arranged on at least one axial outer side of a rocker arm. Alternatively, the carrier can be connected directly to the cylinder head of the internal combustion engine.

The rocker arm arrangement can be used particularly advantageously in heavy-duty engines, in particular in four-valve truck engines with a camshaft, in particular with regard to the installation conditions and mode of operation.

The object according to the invention is also achieved by a method for operating the above-described rocker arm arrangement, at least three valve control curves being tapped off the camshaft on at least one switchable rocker arm.

In different switching states, the valve control curves can be transmitted independently of one another or in combination to control at least one or more gas exchange valves of the internal combustion engine to optimize the operating point.

In a first switching state, a full valve lift is transmitted to one or more gas exchange valves of the internal combustion engine by tapping a first valve control curve, for example to carry out normal operation of the internal combustion engine.

In a second switching state, a full valve lift and a first partial valve lift connected downstream of this are transmitted by picking off a second valve control cam. In order to thermodynamically optimize the combustion process of the internal combustion engine, one or more exhaust gas exchange valves of the internal combustion engine can be controlled in a simple manner with a downstream small exhaust stroke, in particular to implement exhaust gas recirculation. It is also possible to activate one or more intake gas exchange valves to implement a so-called Miller lift as a small intake lift.

In a third switching state, a full valve lift and a second partial valve lift connected downstream of this are transmitted by picking off a third valve control curve.

As a result, for example, one or more outlet or inlet gas exchange valves can be activated with an engine braking stroke as a so-called engine brake.

In a fourth switching state, no valve lift is transmitted, so that a valve or cylinder is switched off.

In addition, the above-mentioned method for operating the above-described rocker arm arrangement on the second switchable rocker arm can be used to tap a further valve control curve from the camshaft and in the above-mentioned first, second and third switching states a full valve lift can be transmitted to at least one further gas exchange valve. In the aforementioned fourth switching state, no valve lift is transmitted at the second rocker arm, as a result of which valve or cylinder deactivation is carried out.

The coupling and decoupling of the respective cam-side lever arm with or from the respective valve-side lever arm for switching the rocker arms can be done in a simple manner by energizing or de-energizing the respective associated actuator.

Since the actuators for shifting the rocker arms can all be controlled separately and the lever arms on the cam side can be coupled independently of one another, it is possible to implement a large number of other switching states to optimize the operating point of the internal combustion engine be coupled to the valve-side lever arm.

• 1 und 2 eine erfindungsgemäße Kipphebelanordnung für einen Ventiltrieb einer Brennkraftmaschine in zwei perspektivischen Ansichten,
• 3 eine geschnittene Ansicht der Kipphebelanordnung in einem ersten Schaltzustand,
• 4 eine geschnittene Ansicht der Kipphebelanordnung in einem zweiten Schaltzustand,
• 5 eine geschnittene Ansicht der Kipphebelanordnung in einem dritten Schaltzustand.

Further features of the invention result from the following description and from the drawings, in which an exemplary embodiment of the invention is shown in simplified form. Show it:

• 1 and 2 a rocker arm arrangement according to the invention for a valve train of an internal combustion engine in two perspective views,
• 3 a sectional view of the rocker arm assembly in a first switching state,
• 4 a sectional view of the rocker arm assembly in a second switching state,
• 5 a sectional view of the rocker arm assembly in a third switching state.

In the figures, various views of a rocker arm arrangement according to the invention for a valve train of an internal combustion engine are shown by way of example. The method according to the invention is also illustrated on the basis of these illustrations.

In the 1 and 2 Rocker arm arrangement according to the invention shown by way of example comprises a first switchable rocker arm 1 and a second rocker arm 2 which can be switched independently of this, the rocker arms 1, 2 being pivotable relative to one another on a common stationary or machine-fixed rocker arm axis 3.

The first rocker arm 1 has three lever arms 4, 5, 6 on the cam side and one lever arm 7 on the valve side. The lever arms 4, 5, 6, 7 are space-savingly arranged directly next to each other and pivotable to one another on the rocker arm axis 3. The cam-side lever arms 4, 5, 6 are each in contact with a cam 8, 9, 10 of a camshaft 11 of the internal combustion engine for tapping off a valve control curve. The lever arm 7 on the valve side is in contact via a valve bridge with two outlet gas exchange valves 12, 13 of a cylinder of the internal combustion engine (not shown) in order to transmit the valve control curve picked off in each case.

The second switchable rocker arm 2 comprises a further lever arm 14 on the cam side, which is in contact with a further cam 15 of the camshaft 11 for picking up a further valve control curve, preferably for triggering a full valve lift, and a further lever arm 16 on the valve side, which is connected via a valve bridge with two inlet Gas exchange valves 37, 38 of the cylinder, not shown, of the internal combustion engine interacts.

To switch the rocker arms 1, 2, the cam-side lever arms 4, 5, 6 and 14 can each be coupled independently of one another to the respective valve-side lever arm 7 and 14, respectively. As in play off 1 and 2 becomes clear, in the top view of the lever tops 47, 48 of the rocker arms 1, 2, ie looking in the pivoting direction of the same, the cam pickup of the cam-side lever arms 4, 5, 6 or 14 and the valve actuation of the valve-side lever arms 7 or 16 opposite sides 49, 50 of the rocker arm axis 3 are arranged. The latter is positioned between the camshaft 11 and the gas exchange valves 12, 13 and 37, 38, respectively. As shown, the outlet gas exchange valves 12, 13 and the inlet gas exchange valves 37, 38 of a cylinder of the internal combustion engine can be actuated independently of one another by the two switchable rocker arms 1, 2 driven by one camshaft 11.

To minimize the frictional forces, the cam-side lever arms 4, 5, 6, 14 each have a cam roller at the cam-side end, which is in contact with the respective cam 8, 9, 10, 15 of the camshaft 11 for cam pickup.

On the first rocker arm 1, a first lever arm 4 on the cam side is in contact with a first cam 8 or fourth cam 15 of the camshaft 11, each preferably as a so-called full lift cam for picking up a full valve lift for fully opening the exhaust gas exchange valves 12, 13 or the intake Gas exchange valves 37, 38 run.

A second lever arm 5 on the cam side and a third lever arm 6 on the cam side, each in contact with a second cam 9 and a third cam 10, each preferably designed as a multiple cam of the camshaft 11, pick up a full valve lift and an additional valve lift that is phase-shifted with respect to this, preferably as a partial valve lift, see above that two valve lifts can be transmitted with one revolution of the camshaft. The additional valve lift that can be tapped off on the second cam 9 is a small partial valve lift in which the gas exchange valve is only partially opened. Alternatively, the second and third cams 9 and 10 can in particular each be designed as a simple additional lift cam or each as a multiple lift cam with an additional full lift cam.

The valve-side lever arm 7 is arranged between the first and third lever arm 4, 6 on the common rocker arm axis 3, while the second cam-side lever arm 5 is positioned next to the first cam-side lever arm 4 on the rocker arm axis 3, forming an outer side 51 of the first rocker arm 1.

On the second rocker arm, the second lever arm 16 on the valve side is on the inside facing the first rocker arm 1 axially, and the fourth lever arm 14 on the cam side is on the axial outside of the second lever arm 16 on the valve side, facing away from the first rocker arm 1 .

The arrangement of the second and the fourth cam-side lever arm 4, 5 on the outer sides of the rocker arms 1, 2 has the advantage that the second cam 9 and the fourth cam 15 can each be positioned closer to the camshaft bearings 45 and 46, whereby the Load of the camshaft 11 can be reduced by bending moments.

In the the 3 , 4 and 5 the rocker arms 1, 2 are shown in cross-section and with the respective coupling means 17, 18, 19 and 20 and the respective associated actuators 21, 22, 23 and 24 as an example in different switching states. The coupling means 17, 18, 19 and 20 can each be actuated independently of one another by an associated electrical actuator 21, 22, 23 and 24, respectively. The actuators 21, 22, 23 and 24 designed as electric lifting magnets each have displaceable armatures 33, 34, 35 and 36, through which the associated coupling means 17, 18, 19 and 20 can be actuated in direct actuating contact.

The actuators 21, 22, 23, 24 are in accordance with 1 until 5 arranged in a region located between the rocker arm axis 3 and the camshaft 11 and integrated into a support 39 which is connected to the rocker arm axis 3 via screw connections 40,41. The carrier 39 is made in one piece. The second, third and fourth actuators 22, 23, 24 are arranged in an intermediate space defined axially by the rocker arms 1, 2 and are accommodated in a first support housing 42 which is formed on the carrier 39 and which is axially located between the first and second rocker arms 1, 2 and is arranged between the axially inner third cam-side lever arm 6 of the first rocker arm 1 and the axially inner valve-side lever arm 16 of the second rocker arm 2 .

The first actuator 21 is positioned on the axially outer side 51 of the first rocker arm 1 , which is formed by the outer second cam-side lever arm 5 , and is accommodated in a second carrier housing 43 . An axially continuous recess 44 is provided on the outer second lever arm 5 on the cam side, into which the first actuator 21 with the carrier housing 43 protrudes axially and with the armature 33 for direct actuating contact with the first coupling bolt 25 on the inner first lever arm 4 on the cam side through the second lever arm on the cam side 5 reaches through axially. The recess 44 is designed in such a way that, during operation, the second lever arm 5 on the cam side can be pivoted unhindered in a small pivoting angle without being hindered by the first actuator 21 reaching through the lever arm 5 .

The coupling means 17 , 18 , 19 , 20 are arranged at the same or approximately the same radial distance from the rocker arm axis 3 and in an area located between the rocker arm axis 3 and the camshaft 11 . As a result, the actuators 21, 22, 23, 24 can also be positioned at the same or approximately the same radial distance from the rocker arm axis 3.

The coupling means 17, 18, 19 or 20 are integrated in the respective lever arms 4, 5, 6 or 14 and 7 or 16 of the first and second rocker arm 1, 2 and each have coupling bolts arranged displaceably in axial bores for coupling purposes 25, 26, 27, 28 on. In this way, a space-saving so-called transverse locking of the rocker arms 1, 2 is made possible, in which the coupling of the lever arms 4, 5, 6 and 7 or 14 and 16 takes place transversely to the longitudinal axis of the lever, i.e. parallel to the axis of the rocker arm 3.

On the first rocker arm 1, the coupling bolts 25 and 27 assigned to the first lever arm 4 on the cam side and the third lever arm 6 on the cam side are each prestressed into the decoupled state by spring means 29, 31 arranged in the respective bores. For coupling, the coupling bolts 25, 27 can engage in corresponding axial blind holes on the lever arm 7 on the valve side ( 3 and 5 ). In contrast, the coupling pin 26 assigned to the second lever arm 5 on the cam side and the coupling pin 28 assigned to the fourth lever arm 14 on the cam side on the second rocker arm 2 are each prestressed into the coupled state by spring means 31, 32 arranged in the respective bores.

In order to be able to move the coupling bolts 25, 26, 27, 28 into a defined decoupled or defined coupled position, they can each be placed against a stop formed in the respective bore of the cam-side lever arms 4, 6 or the valve-side lever arms 7, 17 is preferably formed by a ring pressed into the bore or a ring shoulder formed on the inner diameter of the respective bore.

In the context of the claimed method, in 3 until 5 the rocker arm arrangement is shown as an example in four different switching states. In a first switching state according to 3 , on the first rocker arm 1 a first actuator 21 actuating the first coupling means 17 and a second actuator 22 actuating the second coupling means 18 are energized. As a result, the coupling pin 25 assigned to the first actuator 21 is moved into the coupled position against the spring force of the spring means 29 and the coupling pin 26 assigned to the second actuator 22 is moved into the decoupled position against the spring force of the spring means 30 . Accordingly, the first lever arm 4 on the cam side is coupled to the first lever arm 7 on the valve side and the second lever arm 5 on the cam side is decoupled from the first lever arm 7 on the valve side. At the same time, the third actuator 23 actuating the third coupling means 19 is de-energized, as a result of which the coupling pin 27 assigned to it is shifted into the decoupled position and the third lever arm 6 on the cam side is decoupled from the first lever arm 7 on the valve side. In this way, only the first cam-side lever arm 4 on the first cam 15 ( 1 ) tapped off the first valve control curve, preferably for controlling a full valve lift, via the coupled first valve-side lever arm 7 to the outlet gas exchange valves 12, 13.

At the same time, a fourth actuator 24 actuating the fourth coupling means 20 is de-energized on the second rocker arm 2 to actuate the inlet gas exchange valves 37, 38, as a result of which the associated coupling pin 28 is displaced into the coupled position by the spring force of the spring means 32. As a result, on the second rocker arm 2, the full valve lift picked up by the fourth cam-side lever arm 14 on the fourth cam 15 is transmitted to the inlet gas exchange valves 37, 38 via the coupled valve-side lever arm 16

in a 4 shown second switching state of the rocker arm assembly are the third and fourth actuator 23, 24 as in the first switching state according 3 described de-energized, with the locked second rocker arm 2, a full valve lift on the intake gas exchange valves 37, 38 is transmitted. In contrast to the first switching state, the first and second actuators 21, 22 are also de-energized in the second switching state. As a result, the coupling pin 25 assigned to the first actuator 21 is pushed into the decoupled position by the spring force of the spring means 29 and the first lever arm 4 on the cam side is decoupled from the first lever arm 7 on the valve side. At the same time, the coupling bolt 26 assigned to the second actuator 22 is pushed into the coupled position by the spring force of the spring means 30 and the second cam-side lever arm 5 is coupled to the first valve-side lever arm 7 .

In this way, on the first rocker arm 1, the second valve control curve picked up solely by the second lever arm 5 on the cam side on the second cam 9, preferably for controlling a full valve lift and a partial valve lift phase-shifted relative to this, is transmitted via the coupled first lever arm 7 on the valve side to the exhaust gas exchange valves 12, 13. This is a thermodynamic optimization of the combustion process of the internal combustion engine, for example by an internal Exhaust gas recirculation of the internal combustion engine, feasible.

Alternatively, the first lever arm 4 on the cam side is additionally coupled to the first lever arm 7 on the valve side. As a result, both the first cam 8 ( 1 ).

A third switching state of the rocker arm assembly according to 5 provides that the first and fourth actuator 21, 24 according to the second switching state 4 is de-energized, with the locked second rocker arm 2 a full valve lift on the intake gas exchange valves 37, 38 is transmitted. Unlike in the second switching state, the second and third actuators 22, 23 are energized. As a result, the coupling pin 26 assigned to the second actuator 22 is moved into the decoupled position against the spring force of the spring means 30 and the coupling pin 27 assigned to the third actuator 23 is moved into the coupled position against the spring force of the spring means 31 . Thus, the second cam-side lever arm 5 is decoupled from the first valve-side lever arm 7 and the third cam-side lever arm 6 is coupled to the first valve-side lever arm 7 . As a result, the third cam 10 ( 1 ) Tapped off third valve control curve, preferably for controlling a full valve lift and an additional valve lift phase-shifted to this, via the coupled first valve-side lever arm 7 to the outlet gas exchange valves 12, 13. In this way, a so-called engine brake can be implemented on the first rocker arm 1 in particular, in which the exhaust gas exchange valves 12, 13 are briefly opened at the end of the compression stroke in the cylinder, out of phase with the full valve lift in the cam base circle phase, and the resulting decompression achieves an engine braking effect.

Alternatively, the first lever arm 4 on the cam side is coupled to the first lever arm 7 on the valve side by energizing the first actuator 21 . As a result, both the first cam 8 ( 1 ) Tapped full valve lift as well as the additional valve lift connected downstream of this as an alternative third cam contour on the third lever arm 5 on the cam side.

In a fourth switching state of the rocker arm arrangement (not shown), the second and fourth actuators 22, 24 are energized, as a result of which the coupling bolts 26, 28 are pushed into the decoupled position against the spring force of the spring means 30, 32 and the second cam-side lever arm 5 is released from the first valve-side lever arm 7 or , the fourth lever arm 14 on the cam side can be decoupled from the second lever arm 16 on the valve side. At the same time, the first and third actuators 21, 23 are switched off. As a result, the first and third coupling bolts 25, 27 are pushed into the decoupled position by the spring force of the spring means 29, 31, and the first and third lever arm 4, 6 on the cam side is decoupled from the first lever arm 7 on the valve side. Thus, both the first and the second valve-side lever arm 7, 14 are decoupled from the cam-side lever arms 4, 5, 6 or 14 and the first and second rocker arm 1, 2 are unlocked, so that both the first and the second rocker arm 1, 2 no valve lift is transmitted and cylinder deactivation is implemented.

Reference List

1

rocker arm

2

rocker arm

3

rocker arm axis

4

cam-side lever arm

5

cam-side lever arm

6

cam-side lever arm

7

valve-side lever arm

8th

cam

9

cam

10

cam

11

camshaft

12

gas exchange valve

13

gas exchange valve

14

cam-side lever arm

15

cam

16

valve-side lever arm

17

couplant

18

couplant

19

couplant

20

couplant

21

actuator

22

actuator

23

actuator

24

actuator

25

coupling pin

26

coupling pin

27

coupling pin

28

coupling pin

29

spring means

30

spring means

31

spring means

32

spring means

33

anchor

34

anchor

35

anchor

36

anchor

37

gas exchange valve

38

gas exchange valve

39

carrier

40

screw connection

41

screw connection

42

carrier housing

43

carrier housing

44

recess

45

camshaft bearings

46

camshaft bearings

47

lever top

48

lever top

49

side

50

side

51

outside

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017129720 A1 [0002]

Claims (10)

Rocker arm arrangement for a valve drive of an internal combustion engine, with at least one switchable rocker arm (1) arranged pivotably on a rocker arm axis (3), characterized in that the rocker arm (1) has at least three lever arms (4, 5, 6) on the cam side, each for picking up a valve control curve from a camshaft (11) of the internal combustion engine and at least one lever arm (7) on the valve side for actuating at least one gas exchange valve (12, 13) of the internal combustion engine, the lever arms (4, 5, 6, 7) being pivotable relative to one another on the common rocker arm axis (3) arranged and for switching the rocker arm (1), the cam-side lever arms (4, 5, 6) can be coupled independently of one another to the valve-side lever arm (7) for valve actuation. rocker arm arrangement claim 1 , characterized in that a first cam-side lever arm (4) for picking up a first valve control curve is in contact with at least one first cam (8) of the camshaft (11) and a second cam-side lever arm (5) for picking up a second valve control curve is in contact with at least one second cam (9) of the camshaft (11) and a third cam-side lever arm (5) for picking up a third valve control curve is in contact with at least a third cam (10) of the camshaft (11). rocker arm arrangement claim 2 , characterized in that the first cam (8) for transmitting a full valve lift and the second and third cams (9, 10) are each designed for transmitting a full valve lift and a phase-shifted downstream valve part lift. Rocker arm assembly according to one of Claims 1 until 3 , characterized in that the pickup of the cam-side lever arms (4, 5, 6) from the camshaft (11) and the valve actuation of the valve-side lever arm (7) are arranged on opposite sides (49, 50) of the rocker arm axis (3). Rocker arm assembly according to one of Claims 1 until 4 , characterized in that the valve-side lever arm (7) is arranged between two cam-side lever arms (4, 6) and, in addition to one of the aforementioned cam-side lever arms (4), another cam-side lever arm (5) forms an outer side (51) of the rocker arm (1). is arranged on the rocker arm axis (3). rocker arm arrangement claim 5 , characterized in that at least one electric actuator (21) is arranged on the outside (51) of the rocker arm (1), wherein an axially continuous recess ( 44) is provided, into which the actuator (21) for switching an inner cam-side lever arm (4) reaches through in direct actuating contact. Rocker arm assembly according to one of Claims 1 until 6 , characterized in that each cam-side lever arm (4, 5, 6, 14) for coupling to a valve-side lever arm (7, 16) is assigned coupling means (17, 18, 19, 20) which are each controlled by an assigned electrical actuator ( 21, 22, 23, 24) can be switched independently of one another in direct control contact. Rocker arm assembly according to one of Claims 1 until 7 , characterized in that an independent of the first rocker arm (1) switchable second rocker arm (2) on the common rocker arm axis (3) is arranged pivotably to the first rocker arm (1), wherein the first rocker arm (1) in valve contact with at least one outlet Gas exchange valve (12, 13) and the second rocker arm (2) is in valve contact with at least one inlet gas exchange valve (37, 38) of the internal combustion engine. Rocker arm assembly according to one of Claims 7 or 8th , characterized in that the actuators (21, 22, 23, 24) are at least partially integrated in a support (39) connected to the rocker arm axis (3) and/or the cylinder head of the internal combustion engine, the support (39) having at least one axially first carrier housing (42) arranged between the first and second rocker arm (1, 2) and at least one second carrier housing (43) arranged on an axial outer side (51) of a rocker arm (1). Method for operating a rocker arm arrangement according to one of the preceding claims, wherein at least three valve control cams are tapped from a camshaft (11) on at least one switchable rocker arm (1) and in a first switching state by tapping a first valve control cam a full valve lift and in a second switching state by tapping a second valve control curve, a full valve lift and a downstream first partial valve lift and in a third switching state by tapping a third valve control curve a full valve lift and a downstream second partial valve lift or in a fourth switching state no valve lift is transmitted to at least one gas exchange valve (12, 13) of the internal combustion engine.

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