Valve train for an internal combustion engine

Abstract

Valve train (1) for an internal combustion engine, with a camshaft (2) having at least one valve actuating cam (3, 4, 5, 6, 7, 8) and a rocker arm (9, 10, 11) having an actuating region (23) which is subjected to force at least once per revolution of the camshaft (2) by the valve actuating cam (3, 4, 5, 6, 7, 8), wherein the rocker arm (9, 10, 11) is rotatably mounted on a bearing point (18) about a rocker arm rotation axis (19) on the one hand of the actuating region (23) and has a contact region (24) on the other hand of the actuating region (23), via which the rocker arm (9, 10, 11) actuates a gas exchange valve (12, 13, 14, 15, 16, 17) of the valve train (1) when force is applied to the actuating region (23), wherein the rocker arm (9,10,11) is displaceable relative to the camshaft (2) so that a lever distance between the bearing point (18) and the contact area (24) is adjustable, characterized in that the rocker arm (9,10,11) is designed as a multiple rocker arm supported by a single support element (20), which has a plurality of actuating regions (23) for a plurality of valve actuating cams (3, 4, 5, 6, 7, 8) and a plurality of contact regions (24) for actuating a plurality of gas exchange valves (12, 13, 14, 15, 16, 17) on sides of the bearing point (18) that are axially opposite one another with respect to a camshaft rotation axis (26), wherein the rocker arm (9, 10, 11) is rotatably mounted on a valve clearance compensation element (21) of the support element (20) about the rocker arm rotation axis (19).

Description

[0001] The invention relates to a valve train for an internal combustion engine, with a camshaft having at least one valve actuating cam and a rocker arm having an actuating region which is subjected to a force by the valve actuating cam at least once per revolution of the camshaft, wherein the rocker arm is rotatably mounted on a bearing point about a rocker arm rotation axis on the one hand of the actuating region and has a contact region on the other hand of the actuating region via which the rocker arm actuates a gas exchange valve of the valve train when a force is applied to the actuating region, wherein the rocker arm is displaceable with respect to the camshaft, in particular is rotatably mounted with respect to an adjusting axis of rotation different from the rocker arm rotation axis, so that a lever distance between the bearing point and the contact region is adjustable.

[0002] The valve train serves to actuate at least one gas exchange valve. This can be configured, for example, as a gas inlet valve or a gas outlet valve. The valve train, together with the gas exchange valve, can form a component of the internal combustion engine. It has the camshaft, which is preferably driven by a crankshaft of the internal combustion engine and is operatively connected to it, preferably rigidly and / or permanently. Of course, a camshaft adjuster can be present in the operative connection between the crankshaft and the camshaft, by means of which an angular offset between the crankshaft and the camshaft can be adjusted.

[0003] For example, US Pat. No. 8,601,989 B2 is known from the prior art. This describes a variable valve train for an internal combustion engine.

[0004] The document US 5 003 939 A relates to a device for continuously varying the duration of the intake and exhaust processes and the valve lift over the entire operating range of an internal combustion engine; wherein the device uses two valves for each of the intake and exhaust functions in a combustion chamber with four valves; wherein each pair of valves is driven by a different camshaft; wherein for each valve there is a rotatable drum having a common axis with the camshaft and a valve actuating rocker arm which is pivotally mounted at one end within the drum; wherein an angular rotation of the drum causes the cam to reciprocate the rocker arm and thus the valve at an earlier or later point in the cam rotation.The combination, for example, of an earlier opening point of the first valve and a later closing point of the second valve results in an extended duration of the process associated with the two valves. The variable valve lift feature occurs when the angular rotation of the drum changes the geometric relationship between the rocker arm pivot point, the cam contact pad on the rocker arm, and the free end of the rocker arm that drives the valve.

[0005] Furthermore, the prior art documents JP H07- 77 020 A, US 2002 / 0 129 779 A1, US 5 205 247 A, JP S63- 297 713 A, DE 42 35 934 A1, DE 43 43 952 A1 and US 5 033 420 A are known.

[0006] It is an object of the invention to propose a valve train for an internal combustion engine which has advantages over known valve trains, in particular enabling a change in control times and / or a stroke of the gas exchange valve in a simple manner.

[0007] This is achieved according to the invention with a valve train having the features of claim 1. It is provided that the rocker arm is designed as a multiple rocker arm mounted by means of a single support element, which has a plurality of actuating regions for a plurality of valve actuating cams and a plurality of contact regions for actuating a plurality of gas exchange valves on opposite sides of the bearing point in the axial direction with respect to the camshaft rotation axis, wherein the rocker arm is rotatably mounted on a valve clearance compensation element of the support element about the rocker arm rotation axis.

[0008] The camshaft has at least one valve actuation cam, which serves to actuate the gas exchange valve. The gas exchange valve is actuated by the valve actuation cam via the rocker arm, via which an operative connection exists, at least temporarily, between the valve actuation cam and the gas exchange valve. The rocker arm has the actuation area, which is subjected to a force by the valve actuation cam at least once per revolution of the camshaft. This means that the valve actuation cam pushes the actuation area away from a rotational axis of the camshaft at least once per revolution of the camshaft, so that the force is applied to the actuation area or the rocker arm.

[0009] On one side of the actuating area, the rocker arm is mounted for rotation about the rocker arm rotation axis. The mounting is located at the bearing point. When the actuating area is actuated by the valve actuating cam, the rocker arm is rotated or deflected about the rocker arm rotation axis, so that the contact area on the other side of the actuating area comes into operative connection with the gas exchange valve and actuates it, in particular to at least partially open it.

[0010] If the actuating area is shifted due to the force applied by the valve actuating cam, the contact area is also deflected and the gas exchange valve is actuated accordingly. For example, the actuating area rests against the gas exchange valve, here in particular against a valve stem of the gas exchange valve. However, it can also be provided that the actuating area rests against an actuating element, which in turn is operatively connected to the gas exchange valve or its valve stem. Preferably, at least one valve spring is assigned to the gas exchange valve, which exerts a spring force on the gas exchange valve that counteracts the actuation of the gas exchange valve by the rocker arm.

[0011] The valve train is designed to enable a change in the actuation parameters of the gas exchange valve, for example, the control timing and / or the stroke of the gas exchange valve. Control timing includes, for example, an opening time at which the gas exchange valve is moved out of a closed position and / or a closing time at which the gas exchange valve returns to the closed position.

[0012] This means that the valve train can also influence the duration of the gas exchange valve's opening period, which is limited on the one hand by the opening time and on the other hand by the closing time, and during which the gas exchange valve is outside its closed position, i.e., at least partially open. The stroke of the gas exchange valve is the extent to which the gas exchange valve is displaced from its closed position; in other words, the displacement of the gas exchange valve at which the maximum flow cross-section is achieved, which is released by the gas exchange valve during the opening period.

[0013] To achieve adjustability of the actuation parameters, i.e., to create a variable valve train, the rocker arm must be movable relative to the camshaft. This displacement allows the lever distance between the bearing point and the contact area to be adjusted, while preferably the lever distance between the bearing point and the actuation area remains constant or at least nearly constant, or changes to a lesser extent than the lever distance between the bearing point and the contact area with the same rocker arm displacement.

[0014] In other words, the distance of the actuating area, at which the rocker arm is subjected to force by the valve actuating cam, from the bearing point should not change or should change only slightly, while the distance between the bearing point and the contact area changes such that the gas exchange valve opens at the desired opening time and closes again at the desired closing time, wherein the stroke of the gas exchange valve achieved during the opening period enclosed by the opening time and the closing time also corresponds to the desired stroke.

[0015] Particularly preferably, the rocker arm is rotatably mounted relative to the adjusting axis of rotation, wherein the adjusting axis of rotation is different from the rocker arm axis of rotation. For example, the adjusting axis of rotation corresponds to the axis of rotation of the camshaft, which can also be referred to as the camshaft axis of rotation. This enables a particularly simple implementation of the valve train.

[0016] A further embodiment of the invention provides that the actuation area is located on a curved sliding surface of the rocker arm. The sliding surface is curved in the circumferential direction with respect to the rocker arm rotation axis or, preferably, the actuating rotation axis, thus having different distances from this rotation axis along its length. The curvature of the sliding surface can be uniform over its entire extent. However, the curvature can also change in order to achieve the desired opening time, the desired closing time, and / or the desired stroke for a specific position of the rocker arm with respect to the camshaft, in particular a specific rotation angle position.

[0017] The actuation range always describes the area of ​​the sliding surface over which the sliding surface actuates the gas exchange valve when force is applied to the actuation range, i.e., the area that deflects the gas exchange valve or the actuating element assigned to the gas exchange valve to actuate the gas exchange valve. It can be provided that the gas exchange valve or the actuating element permanently rests against the sliding surface of the rocker arm, i.e., is in contact with it, at least when the gas exchange valve is in its closed position. In this way, a particularly low valve clearance or a low idle stroke of the valve train is achieved.

[0018] Within the scope of a further embodiment of the invention, it can be provided that the adjusting axis of rotation corresponds to a camshaft axis of rotation of the camshaft. This has already been mentioned above. Such a selection of the adjusting axis of rotation enables a particularly simple implementation of the valve train, which also offers excellent adjustability.

[0019] A further development of the invention provides that the rocker arm is designed as a roller rocker arm, wherein the actuating region is present on a rotatably mounted roller of the rocker arm. In this respect, the rocker arm has the roller which is rotatably mounted on it, in particular about a roller axis of rotation which is different from the rocker arm axis of rotation and / or the adjusting axis of rotation, in particular spaced parallel to the rocker arm axis of rotation and / or the adjusting axis of rotation. By using the roller rocker arm, the friction between the valve actuating cam and the rocker arm can be significantly reduced because the force applied to the rocker arm by the valve actuating cam occurs via the roller, which in this case describes a rotary movement. For example, the roller is mounted on the rocker arm by means of a rolling bearing, in particular by means of a needle bearing or cylindrical roller bearing.

[0020] A further preferred embodiment of the invention provides that the rocker arm is mounted rotatably with respect to the support element about the rocker arm rotation axis, and the support element is mounted rotatably with respect to the adjustment axis. The rocker arm's bearing point thus rests, for example, on the support element or is rotatably mounted on it. The support element serves to support the rocker arm at the bearing point, in particular while the rocker arm is subjected to force by the valve actuating cam. The support element, in turn, is displaceable with respect to the camshaft, in particular, is mounted rotatably about the adjustment axis.

[0021] While the rocker arm is deflected relative to the support element, in particular rotated about the rocker arm rotation axis, during the application of force to the rocker arm by the valve actuating cam, it is provided to displace the rocker arm together with the support element relative to the camshaft in order to adjust the opening time, the closing time, and / or the stroke. Particularly preferably, it is provided to rotate the rocker arm together with the support element about the adjusting rotation axis, whereby different actuation parameters, for example, different control times and / or different strokes, are available for different positions of the support element, in particular for different rotational angle positions of the support element.

[0022] The invention provides that the rocker arm is mounted on a valve clearance compensation element of the support element so as to be rotatable about the rocker arm rotation axis. The valve clearance compensation element, which is preferably designed as a hydraulic valve clearance compensation element (HVA), serves to compensate, in particular to reduce, preferably eliminate, the valve clearance. Ideally, the valve clearance compensation element thus ensures that the rocker arm is permanently in contact with the valve actuation cam on the one hand, and with the actuation area on the gas exchange valve or the actuation element on the other, without the gas exchange valve actually having to be actuated.

[0023] In particular, the gas exchange valve is not actuated if the actuating area of ​​the rocker arm rests against a base circle of the valve actuating cam. Actuation therefore only occurs when a cam projection of the valve actuating cam, which protrudes beyond the base circle, rests against the actuating area. With the help of the valve lash adjuster, which reduces or even eliminates the valve clearance, it is now possible to ensure that the gas exchange valve is actuated immediately as soon as the actuating area is subjected to force by the cam projection. For example, the bearing point of the rocker arm rests on the valve lash adjuster, so that the rocker arm as a whole is supported on the valve lash adjuster.

[0024] The invention provides that the rocker arm is designed as a multiple rocker arm, which has multiple actuation areas for multiple valve actuation cams and multiple contact areas for actuating multiple gas exchange valves, in particular on opposite sides of the bearing point in the axial direction relative to the camshaft rotation axis. With the aid of the rocker arm, multiple gas exchange valves can be actuated, with each of the gas exchange valves preferably being assigned a separate valve actuation cam of the camshaft.

[0025] Accordingly, the multiple rocker arm has several actuating areas, in particular one actuating area for each valve actuating cam, which serves to actuate a gas exchange valve assigned to the rocker arm. Each actuating area is preferably assigned precisely one of the contact areas, whereby when force is applied to one of the actuating areas, only the gas exchange valve that interacts with the contact area assigned to the force-applied actuating area is actuated. The valve actuating cams assigned to the multiple rocker arm are preferably of identical design.

[0026] The actuation parameters are adjusted jointly for the gas exchange valves assigned to the rocker arm by moving the rocker arm. This has the advantage that the number of required rocker arms can be significantly reduced. For example, the gas exchange valves assigned to the same rocker arm are also assigned to the same cylinder of the internal combustion engine. In this respect, the gas exchange valves assigned to the multiple rocker arm represent, for example, gas inlet valves or gas outlet valves of the same cylinder.

[0027] The actuation areas and contact areas of the rocker arm are preferably arranged on opposite sides of the bearing in the axial direction relative to the camshaft rotation axis. In particular, exactly one actuation area and exactly one contact area are provided on each side of the bearing, viewed in the axial direction. Of course, however, multiple actuation areas and multiple contact areas can also be present on each side, with the same number of actuation areas and contact areas preferably being present on each side of the bearing.

[0028] The invention provides that the multiple rocker arm is mounted by means of a single support element. Accordingly, the number of parts of the valve train can be significantly reduced; in particular, if one is present, only one valve clearance compensation element is required to compensate, in particular to eliminate, the valve clearances of the gas exchange valves assigned to the multiple rocker arm.

[0029] In a further embodiment of the invention, the support element can be rotatably mounted on the camshaft. This enables simple implementation of the valve train. For example, the support element is mounted on the camshaft directly adjacent to the valve actuation cam which interacts with the actuation area of ​​the rocker arm to actuate the gas exchange valve. If the rocker arm is designed as a multiple rocker arm, i.e., if it is subjected to force by several valve actuation cams, the support element can be mounted on the camshaft between these valve actuation cams, in particular such that it bears axially against at least one of the valve actuation cams, preferably against both valve actuation cams.

[0030] Finally, in a further preferred embodiment of the invention, it can be provided that the support element can be displaced via an adjustment axis by means of an actuator, in particular can be rotated about the adjustment axis of rotation, in particular a plurality of support elements can be connected to one another via the adjustment axis and can be displaced jointly by means of the actuator. The adjustment axis is thus assigned to the support element or is operatively connected to it. The actuator acts on the adjustment axis in order to effect the displacement of the support element in order to adjust the actuation parameters. Particularly preferably, the support element can be rotated about the adjustment axis with the aid of the actuator. If a plurality of support elements and correspondingly a plurality of rocker arms are provided, these plurality of support elements can be connected to one another via the adjustment axis of rotation, so that a joint displacement with the aid of the actuator is possible.

[0031] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention. In the drawings: Fig. 1 a schematic representation of a part of a valve train for an internal combustion engine, which has a camshaft and several gas exchange valves, Fig. 2 a schematic side view of the valve train, wherein a rocker arm is arranged in a first rocker arm position, in which first actuation parameters for a gas exchange valve assigned to the rocker arm are present, and Fig. 3 a side view of the valve train, wherein the rocker arm is in a second rocker arm position in which second actuation parameters are present for the associated gas exchange valve.

[0032] The Fig. Figure 1 shows a schematic representation of a valve train 1 for an internal combustion engine (not shown in detail). The valve train 1 has a camshaft 2 on which several valve actuation cams 3, 4, 5, 6, 7, and 8 are arranged. Two of the valve actuation cams 3, 4, 5, 6, 7, and 8 are assigned to a respective rocker arm 9, 10, and 11, via which gas exchange valves 12, 13, 14, 15, 16, and 17 can be actuated by the valve actuation cams 3, 4, 5, 6, 7, and 8. The valve actuating cams 3 and 4 as well as the gas exchange valves 12 and 13 can be operatively connected to one another via the rocker arm 9, the valve actuating cams 5 and 6 as well as the gas exchange valves 14 and 15 via the rocker arm 10 and finally the valve actuating cams 7 and 8 as well as the gas exchange valves 16 and 17 via the rocker arm 11.

[0033] The following only addresses rocker arm 9, valve actuation cams 3 and 4, and gas exchange valves 12 and 13. However, the explanations are always analogously transferable to the other rocker arms 10 and 11, the other valve actuation cams 5, 6, 7, and 8, and the other gas exchange valves 14, 15, 16, and 17.

[0034] The rocker arm 9 is rotatably mounted about a rocker arm rotation axis 19 at a bearing point 18, which is only partially visible here. For this purpose, it sits with the bearing point 18 on a support element 20, in particular a valve clearance compensation element 21 of the support element 20. The rocker arm 9 is designed as a roller rocker arm, i.e., has at least one rotatably mounted roller 22. In the exemplary embodiment illustrated here, the rocker arm 9 is also a multiple rocker arm, which serves to actuate several gas exchange valves, namely the gas exchange valves 12 and 13. Accordingly, the rocker arm 9 can be subjected to force by several valve actuation cams, namely the valve actuation cams 3 and 4.The gas exchange valves 12 and 13 or 12 and 13; 14 and 15; 16 and 17 respectively assigned to the rocker arm 9 or the rocker arms 9, 10 and 11 are preferably of identical design and arranged such that they act upon the corresponding rocker arm 9, 10 or 11 with the same deflection at the same time.

[0035] Each of the valve actuating cams 3 and 4 is assigned a roller 22, via which it can apply force to the rocker arm 9. Each of the valve actuating cams 3 and 4 can control exactly one of the gas exchange valves 12 and 13, namely the valve actuating cam 3 controls the gas exchange valve 12 and the valve actuating cam 4 controls the gas exchange valve 13. For this purpose, the rocker arm 9 has an actuating region 23 for each of the valve actuating cams 3, which, if the rocker arm 9 is designed as a roller rocker arm, is present on the corresponding roller 22.

[0036] Furthermore, the rocker arm 9 has a contact area 24 for each of the gas exchange valves 12 and 13, via which the respective gas exchange valve 12 or 13 can be actuated when a force is applied to the corresponding actuating area 23 by the respective valve actuating cam 3 or 4. When a force is applied to the actuating area 23 by the valve actuating cam 3, the gas exchange valve 12 is actuated, while when a force is applied to the other actuating area 23 by the valve actuating cam 4, the gas exchange valve 13 is actuated.

[0037] The contact areas 24, via which these actuations occur, are operatively connected to the respective gas exchange valve 12 or 13 for actuation. This can be achieved, for example, by direct contact between the respective contact area 24 and the corresponding gas exchange valve 12 or 13. Of course, an actuating element 25 can be present between the contact area 24 and the respective gas exchange valve 12 or 13.

[0038] It is now provided that the rocker arm 9 or all of the rocker arms 9, 10 and 11 are displaceable relative to the camshaft 2, in particular are rotatably mounted about an adjusting axis of rotation different from the rocker arm axis of rotation 19. In the exemplary embodiment shown here, the adjusting axis of rotation is an axis of rotation 26 of the camshaft 2, i.e., the camshaft axis of rotation. The rocker arms 9, 10 and 11 or the support element 20 assigned to them in each case are connected to one another via an adjusting axis 27, which is actuated by an actuator. The actuator can, for example, be a servomotor, a vacuum actuator, or an oil pressure actuator. With the aid of the actuator, the rocker arms 9, 10 and 11 or the support elements 20 assigned to them in each case are displaceable together relative to the camshaft 2, in particular rotatable about the adjusting axis of rotation 26.

[0039] The rocker arms 9, 10, and 11 can be moved to different rocker arm positions, with each rocker arm position being assigned actuation parameters of the gas exchange valves 12 and 13 (and, of course, the gas exchange valves 14, 15, 16, and 17) that differ from the actuation parameters of other rocker arm positions. The actuation parameters include, for example, the opening time, the closing time, the length of the opening period limited by the opening time and the closing time, and the stroke of the gas exchange valves 12 and 13.

[0040] The support element 20 is rotatably mounted on the camshaft 2. For this purpose, it has, for example, a bearing that completely encompasses the camshaft 2 in the circumferential direction with respect to the camshaft rotation axis 26. To facilitate assembly, the bearing is designed, for example, as a split bearing. The bearing can be designed either as a plain bearing or as a rolling bearing. The support element 20 is preferably mounted, viewed in the axial direction, between the valve actuating cams 3 and 4 assigned to the corresponding rocker arm 9, in particular such that, viewed in the axial direction, it rests on the one hand against the valve actuating cam 3 and on the other hand against the valve actuating cam 4. As a result, the support element 20 and, accordingly, the rocker arm 9 are fixed in the axial direction by the valve actuating cams 3 and 4, so that no further measures are necessary to fix the rocker arm 9 in the axial direction.

[0041] The Fig. Figure 2 shows a side view of the valve train 1, particularly showing the rocker arm 9 and the support element 20. The rocker arm 9 is in a first rocker arm position. It is clear that the lever distance between the bearing point 18 or the rocker arm rotation axis 19 and the actuation area 23, on the one hand, almost corresponds to the lever distance between the bearing point 18 or the rocker arm rotation axis 19 and the contact area 24, on the other hand. In this rocker arm position, the first actuation parameters for the gas exchange valves 12 and 13 are present.

[0042] It can be seen that the contact area 24 is located on a curved sliding surface 28 of the rocker arm 9. The sliding surface is curved in the circumferential direction with respect to the camshaft rotation axis 26; in particular, it has different distances from the camshaft rotation axis 26 in the radial direction along its circumferential extension. By displacing the rocker arm 9, in particular by rotating the rocker arm 9 about the adjusting rotation axis or the camshaft rotation axis 26, the lever distance between the bearing point 18 and the contact area 24 can be adjusted accordingly.

[0043] This is done using the Fig.3. This again shows the side view of the valve train 1, but now the rocker arm 9 is in a second rocker arm position, which is different from the first rocker arm position. For this purpose, the rocker arm 9 was rotated with the support element 20 about the actuating axis of rotation, corresponding to the camshaft axis of rotation 26. It can be seen that the lever distance between the bearing point 18 and the actuating region 23 is essentially identical to the lever distance in the first rocker arm position. However, the lever distance between the bearing point 18 and the contact region 24 is significantly greater than for the first rocker arm position, so that different actuation parameters now exist for the gas exchange valves 12 and 13. In the illustration shown, for example, the gas exchange valve 14 is deflected by the associated valve actuation cam 5, while the gas exchange valve 12 is in its closed position.

[0044] With the described configuration, a variable valve train 1 can be easily implemented, preferably comprising a rocker arm 9 or roller rocker arm rotatably mounted on the camshaft 2. For example, with the valve train 1, a control range of 80° crankshaft rotation angle, a maximum lift of 3 mm to 10 mm, and an opening period of the gas exchange valves 12, 13, 14, 15, 16, and 17 of 140° to 180° crankshaft rotation angle can be realized. Furthermore, a displacement of the rocker arms 9, 10, and 11 into different rocker arm positions is possible with minimal energy expenditure.

Claims

[1] Valve train (1) for an internal combustion engine, with a camshaft (2) having at least one valve actuating cam (3, 4, 5, 6, 7, 8) and a rocker arm (9, 10, 11) having an actuating region (23) which is subjected to force at least once per revolution of the camshaft (2) by the valve actuating cam (3, 4, 5, 6, 7, 8), wherein the rocker arm (9, 10, 11) is rotatably mounted on a bearing point (18) about a rocker arm rotation axis (19) on the one hand of the actuating region (23) and has a contact region (24) on the other hand of the actuating region (23), via which the rocker arm (9, 10, 11) actuates a gas exchange valve (12, 13, 14, 15, 16, 17) of the valve train (1) when force is applied to the actuating region (23), wherein the rocker arm (9,10,11) is displaceable relative to the camshaft (2) so that a lever distance between the bearing point (18) and the contact area (24) can be adjusted, characterized byin that the rocker arm (9, 10, 11) is designed as a multiple rocker arm mounted by means of a single support element (20), which has a plurality of actuating regions (23) for a plurality of valve actuating cams (3, 4, 5, 6, 7, 8) and a plurality of contact regions (24) for actuating a plurality of gas exchange valves (12, 13, 14, 15, 16, 17) on sides of the bearing point (18) that are opposite one another in the axial direction with respect to a camshaft rotation axis (26), wherein the rocker arm (9, 10, 11) is mounted on a valve clearance compensation element (21) of the support element (20) so as to be rotatable about the rocker arm rotation axis (19). [2] Valve train according to claim 1, characterized by that the actuating area (23) is located on a curved sliding surface (28) of the rocker arm (9,10,11). [3] Valve train according to one of the preceding claims, characterized bythat the rocker arm (9, 10, 11) is rotatably mounted with respect to an adjusting axis of rotation (26) different from the rocker arm axis of rotation (19), wherein the adjusting axis of rotation (26) corresponds to the camshaft axis of rotation (26) of the camshaft (2). [4] Valve train according to one of the preceding claims, characterized by that the rocker arm (9,10,11) is designed as a roller rocker arm, wherein the actuating region (23) is present on a rotatably mounted roller (22) of the rocker arm (9,10,11). [5] Valve train according to one of the preceding claims, characterized by that the rocker arm (9, 10, 11) is mounted so as to be rotatable about the rocker arm rotation axis (19) with respect to the support element (20) and the support element (20) is displaceable with respect to the camshaft (2), in particular is mounted so as to be rotatable about the adjusting rotation axis (26). [6] Valve train according to one of the preceding claims, characterized by that the support element (20) is rotatably mounted on the camshaft (2). [7] Valve train according to one of the preceding claims, characterized by that the support element (20) can be displaced via an adjusting axis (27) by means of an actuator, in particular can be rotated about the adjusting axis of rotation (26), in particular a plurality of support elements (20) are connected to one another via the adjusting axis (27) and can be displaced together by means of the actuator.

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