EP3401517B1 - Valve gear lever - Google Patents

Description

The present invention relates to a valve drive lever for actuating a valve of a reciprocating piston engine, in particular an internal combustion engine. In particular, without being restricted thereto, a valve drive lever for actuating a valve for removing compressed gases, in particular compressed air, from a combustion chamber of the internal combustion engine and an internal combustion engine equipped with such a valve drive lever are disclosed.

The internal combustion engine of a motor vehicle, in particular a utility vehicle, can be used to supply compressed air. For example, in the overrun or engine braking operation with a non-fired internal combustion engine, this can be used as a compressor to generate the compressed air. Furthermore, gases compressed at defined operating cycles can be taken from the combustion chamber of the internal combustion engine.

The document JP S57 182205 U describes a valve train of a suction valve with a rocker arm, which rests on a first cam for low speeds and on a second cam for high speeds of an engine.

The document WO 2014/152944 A1 describes a valve actuation system for an internal combustion engine, which comprises a rocker arm in rotary coupling with a camshaft via a follower to each of two cams. The first cam is used for the clocked release of combustion exhaust gas, while the second cam is used to brake the engine.

The document JP 2011 185145 A describes a method to reduce engine braking when idling by the cams of the intake valve and exhaust valve each having two different profiles for normal driving and driving at idle, the profiles for driving at idling each protruding piece by piece from the profiles for normal driving.

The document CN 102 787 880 B describes a rocker arm, at one end of which the movement of a main piston is controlled during normal driving via a cam with multiple bulges and at the other end of which an auxiliary piston is controlled during braking in front of an exhaust valve and the movement of the rocker arm is limited on one side by a brake clamp.

The disclosure document AT 514127 A1 describes a valve through which air is discharged when there is excess pressure in the combustion chamber. The valve is periodically opened by a cam via a rocker arm at defined operating cycles of the internal combustion engine. A piston-cylinder unit is integrated in the arm of the rocker arm on the cam side, the piston of which interacts with the cam via a roller tappet. When pressure is applied in the pressure chamber of the piston-cylinder unit, the rocker arm is effective. When the piston-cylinder unit is depressurized, the rocker arm is not actuated and the valve remains closed.

However, the known rocker arm does not assume a defined position when the piston-cylinder unit is depressurized. This is disadvantageous for the efficiency of the internal combustion engine and also for running noise and wear. In particular, the conventional rocker arm in the unpressurized state does not ensure continuous rolling contact between the roller tappet and the cam.

Another disadvantage of the conventional rocker arm is its moment of inertia. When pressurized, the piston-cylinder unit must also transmit the inertial forces of the rocker arm. This is generally not ensured by a larger dimensioning of the piston-cylinder unit, since this also increases the moment of inertia of the rocker arm. The lubricating oil pressure of the internal combustion engine that is available for pressurization is also predetermined by its operating state and can be below 1 bar in idle operation.

The object is therefore to provide a technique for actuating the valve that improves the efficiency, running noise and / or wear. Another or alternative task is to control the actuation of the valve by means of the oil pressure available for a reciprocating piston engine.

This object or objects are achieved by a valve drive lever for actuating a valve of a reciprocating piston engine, in particular an internal combustion engine, and a correspondingly equipped reciprocating piston engine according to claims 1 and 10.

According to one aspect, a valve train lever comprises a lever arm pivotable about an axis; a pick-up element which rests on a cam of a camshaft of the reciprocating piston machine or can be brought into contact; a coupling mechanism via which the pick-up element is resiliently coupled to the lever arm in a first state and rigidly coupled in a second state; and an actuating element which is connected to the lever arm and rests on or can be brought into contact with a valve stem of the valve.

As a result of the spring-elastic coupling in the first state, the lever arm can assume a rest position, while the pick-off element follows a contour of the cam due to the spring elasticity. The first state can also be referred to as the idle state of the valve drive lever. In the second state, due to the rigid coupling, the valve of the reciprocating piston machine can be actuated by the rigid coupling of the pick-up element causing the pivoting movement of the lever arm and thus actuation by the actuating element.

Since the lever arm and the actuating element assume a rest position in the first state, running noise and / or power losses can be reduced. While the lever arm and the actuating element remain in the rest position in the first state, the pick-up element can follow the cam contour due to the resilient coupling to reduce power loss, running noise and / or wear.

The reciprocating piston engine can be an internal combustion engine. The reciprocating machine can be stationary or mobile.

The valve drive lever can be designed as a rocker arm. The pick-off element can be arranged at a first end of the rocker arm. The actuating element can be arranged at a second end of the rocker arm opposite the first end. On or in the lever arm, a pivot bearing for pivoting the rocker arm between the first end and the second end. Alternatively, the valve drive lever can be designed as a rocker arm. The pick-off element can be arranged at a first point on the rocker arm. The actuating element can be arranged at a second point of the rocker arm that is different from the first point. A pivot bearing for the pivoting movement of the rocker arm can be arranged on or in the lever arm. The first point can be arranged between the pivot bearing and the second point. Alternatively, the second point can be arranged between the pivot bearing and the first point.

The pick-off element is arranged to be movable in a transverse direction transversely to the lever arm, for example by a guide on the lever arm. Alternatively or in addition, the pick-up element can be arranged immovably in a longitudinal direction different from the transverse direction (for example transverse to the transverse direction, in particular parallel to the lever arm).

In the first state and in the second state, the pick-off element can be pretensioned towards the cam and / or rest on the cam. The coupling mechanism can comprise a pressure piston space and a pressure piston movable in the transverse direction in the pressure piston space. The pressure piston can delimit the pressure piston space.

The pressure piston can interact with the pick-off element at least in the second state. In the second state, the pressure piston can interact with the pick-up element in that the pressure piston rests on the pick-up element in the second state, for example on a side of the pick-up element facing the lever arm.

In the second state, the pressure piston chamber can be filled with a hydraulic fluid. The hydraulic fluid can be (at least substantially) incompressible. The hydraulic fluid can comprise oil, in particular lubricating oil from the reciprocating piston machine.

The pick-off element can be prestressed in the transverse direction, for example away from the lever arm and / or towards the cam. The coupling mechanism can comprise a compression spring supported on the lever arm. The compression spring can bias the tapping element in the transverse direction.

The pressure piston can interact with the tapping element in the first state and in the second state. The pressure piston can interact with the pick-up element in the first and second state in that the pressure piston rests against the pick-up element, for example on a side of the pick-off element facing the lever arm. Alternatively, the pressure piston can be connected to the pick-off element. The pressure piston and the pick-up element can be immovable relative to one another in the transverse direction.

The compression spring can be arranged in the pressure piston chamber. The compression spring can rest on the pressure piston. The pressure piston and the pick-off element can jointly follow the contour of the cam in the first state and in the second state.

As an alternative or in addition, the compression spring or another compression spring can rest on the pick-off element.

The pressure piston can be prestressed in the transverse direction, for example towards the lever arm and / or away from the pick-off element. The coupling mechanism can comprise a counter-pressure spring supported on the pick-up element. The counter-pressure spring can be arranged between the pick-off element and the pressure piston. The counter pressure spring can bias the pressure piston in the transverse direction. Alternatively or in addition, the pressure piston can be prestressed by a tension spring attached on the one hand to the lever arm and on the other hand to the pressure piston.

In the first state, the pick-off element can be spaced apart from the pressure piston in the transverse direction, for example due to the bias of the counter-pressure spring and / or tension spring. As an alternative or in addition, in the first state the pressure piston can rest against a lever-near or proximal stop and / or the pressure piston space can assume a minimal size.

In the second state, due to a volume and / or a pressure of the hydraulic fluid in the pressure piston chamber, the counter-pressure spring can contract and / or the tension spring can be stretched against the bias. In the second state, the pressure piston can rest against a lever remote or distal stop and / or the pressure piston space can assume a maximum size.

The pick-up element can follow the contour of the cam in the first state and in the second state. For example, in the first state, only the pick-up element can follow the contour of the cam. The pressure piston can rest in the first state. The pressure piston can rest relative to the lever arm in the first state and in the second state.

The pick-off element can comprise a roller tappet. The roller follower may include a cam follower roller.

The valve drive lever further comprises a control unit for controlling the first state and the second state of the coupling mechanism. On the output side, the control unit is in fluid connection with the pressure piston chamber. On the input side, the control unit is in fluid connection with a control line.

The control unit can comprise a check valve and / or a hydraulic pressure booster. The check valve can open in the direction of flow from the inlet side to the outlet side of the control unit and close vice versa.

The control unit comprises a control piston with an active surface on the inlet side and an active surface on the outlet side for realizing the pressure intensification and for closing a relief line. The output-side effective area is smaller than the input-side effective area. The hydraulic pressure booster can convert an input-side pressure (control pressure) into a greater output-side pressure, for example for pressurizing the pressure piston chamber in the second state. The hydraulic pressure booster and the check valve can be connected in parallel.

In the first state, the control unit connects the output-side fluid connection to the pressure piston chamber with the relief output. In the second state, the control unit can close the output-side fluid connection to the pressure piston chamber. In the second state, the control unit can keep the output-side fluid connection to the pressure piston chamber closed against the greater output-side pressure.

On the input side, the control unit can optionally be in fluid connection with the oil circuit of the reciprocating piston machine via a solenoid valve. The solenoid valve can be arranged in the control line. When the solenoid valve is closed, the control unit can bring about the first state. When the solenoid valve is open, the control unit can bring about the second state.

The actuating element can optionally (for example in the second state) be in fluid connection with the oil circuit of the reciprocating piston machine, for example via the same Magnetic valve. The actuating element can comprise a spherical head connection and / or an actuating surface.

The pick-off element, for example the roller tappet, can be permanently (for example in the first and second state) in fluid connection with the oil circuit of the reciprocating piston engine.

The control unit can be arranged on the coupling mechanism or on a pivot bearing of the pivotable lever arm. The fluid connection or fluid connections between the control unit and the coupling mechanism can comprise bores in the lever arm.

Such a valve drive lever can be used in a reciprocating piston engine, in particular an internal combustion engine or a compressor, for compressing a gas by selective actuation of the valve of the reciprocating piston engine.

According to a further aspect, a reciprocating piston engine, in particular an internal combustion engine, is provided which comprises a valve drive lever according to the first-mentioned aspect. The reciprocating piston engine can comprise a valve for periodically withdrawing a compressed gas from a compression chamber of the reciprocating piston engine, for example a combustion chamber of the internal combustion engine. The reciprocating piston engine can furthermore comprise a camshaft with at least one cam for the selective actuation of the valve via the valve drive lever. The actuation of the valve can be selective by controlling the coupling mechanism of the valve train lever. In the first state, the actuation can be omitted. In the second state, the actuation can be carried out periodically in accordance with the cam.

Such a reciprocating piston machine, for example an internal combustion engine and / or a corresponding device for generating compressed air, can be used stationary or in a motor vehicle. A primary function of the internal combustion engine can be to drive the motor vehicle. A secondary function of the internal combustion engine can be the compression of the gas, for example the generation of compressed air.

Another aspect relates to a motor vehicle with such an internal combustion engine. The motor vehicle can be a land vehicle, a watercraft or an aircraft. The motor vehicle can be used to transport goods and / or passengers. In particular, the motor vehicle can be a utility vehicle (for example a truck or a bus) or a passenger car. That provided by the valve in the second state Compressed gas, for example compressed air, can be fed to a brake system and / or an air spring of the motor vehicle.

Figur 1

eine schematische Darstellung eines ersten Ausführungsbeispiels eines Ventiltriebhebels in einem federelastischen ersten Zustand zu einem ersten Zeitpunkt;

Figur 2

eine schematische Darstellung des ersten Ausführungsbeispiels des Ventiltriebhebels im federelastischen ersten Zustand zu einem zweiten Zeitpunkt;

Figur 3

eine schematische Darstellung des ersten Ausführungsbeispiels des Ventiltriebhebels in einem starren zweiten Zustand zu einem ersten Zeitpunkt;

Figur 4

eine schematische Darstellung des ersten Ausführungsbeispiels des Ventiltriebhebels im starren zweiten Zustand zu einem zweiten Zeitpunkt;

Figur 5

eine schematische Darstellung eines zweiten Ausführungsbeispiels des Ventiltriebhebels mit einer Steuereinheit, die mit jedem Ausführungsbeispiel kombinierbar ist;

Figur 6

eine schematische perspektivische Darstellung eines dritten Ausführungsbeispiels des Ventiltriebhebels, bei dem die Steuereinheit beim Abgriffselement angeordnet ist;

Figur 7

eine schematische Schnittdarstellung des dritten Ausführungsbeispiels in einer Schwenkebene;

Figur 8

einen vergrößerten Ausschnitt der Schnittdarstellung des dritten Ausführungsbeispiels im eingebauten Zustand;

Figur 9

eine schematische Schnittdarstellung eines vierten Ausführungsbeispiels des Ventiltriebhebels in der Schwenkebene; und

Figur 10

eine schematische perspektivische Darstellung eines fünften Ausführungsbeispiels des Ventiltriebhebels, bei dem die Steuereinheit achsennah angeordnet ist.

The features described above can be implemented in any combination. Further features and advantages of the invention are described below with reference to the accompanying drawings. Show it:

Figure 1

a schematic representation of a first embodiment of a valve train lever in a resilient first state at a first point in time;

Figure 2

a schematic representation of the first embodiment of the valve drive lever in the resilient first state at a second point in time;

Figure 3

a schematic representation of the first embodiment of the valve drive lever in a rigid second state at a first point in time;

Figure 4

a schematic representation of the first embodiment of the valve drive lever in the rigid second state at a second point in time;

Figure 5

a schematic representation of a second embodiment of the valve drive lever with a control unit that can be combined with each embodiment;

Figure 6

a schematic perspective illustration of a third embodiment of the valve drive lever, in which the control unit is arranged at the pick-off element;

Figure 7

a schematic sectional view of the third embodiment in a pivot plane;

Figure 8

an enlarged detail of the sectional view of the third embodiment in the installed state;

Figure 9

a schematic sectional view of a fourth embodiment of the valve drive lever in the pivot plane; and

Figure 10

a schematic perspective illustration of a fifth embodiment of the valve drive lever, in which the control unit is arranged close to the axis.

Figure 1 shows schematically a first embodiment of a valve drive lever, generally designated by the reference numeral 100, for actuating a valve 122 of a reciprocating piston engine, in particular an internal combustion engine. The valve train lever 100 comprises a lever arm 102 which is pivotable about a pivot axis 104. At a first point of the lever arm 102, a pick-off element 106 is arranged via a coupling mechanism 110 for interacting with a cam 108 of the reciprocating piston engine. The coupling mechanism 110 comprises a pressure piston chamber 112 for receiving a hydraulic fluid, for example lubricating oil. The pick-off element 106 and / or a pressure piston arranged in the pressure piston chamber 112 has a longitudinal groove into which an anti-rotation lock 116 of the lever arm 102 engages. As a result of the pressurization of the hydraulic fluid, a shoulder 114 on the pick-up element 106 or an element connected to it (eg the pressure piston) comes into contact with a stop (which is, for example, identical to the anti-rotation device 116) of the lever arm 102 or an element connected to it. The coupling mechanism 110 further comprises a compression spring 118, which is supported on the one hand on the lever arm 102 or an element connected to it and on the other hand rests on the pick-up element 106 or an element connected to it (eg the pressure piston). The compression spring 118 can in particular be a spiral spring or a wave spring.

In a first resilient state of the coupling mechanism 110, the pressure piston chamber 112 is pressureless, so that the pick-off element 106 follows the contour of the cam 108 due to the spring tension of the spring 118. For this purpose, the spring tension is dimensioned such that, at a maximum speed, the inertial force of the pick-off element 106 is smaller than the spring tension of the compression spring 118.

Figure 1 shows the spring-elastic first state of the coupling mechanism 110 in a first rotational position of the cam 108. Figure 2 shows the first embodiment in the same first state with a second rotational position of the cam 108, in which the tip of the cam 108 leads the pick-up element 106 to the lever arm 102, reducing the pressure piston space 112 and compressing the compression spring 118. Thus, the lever arm 102 remains on one Actuating element 120 arranged second point of lever arm 102 for actuating valve 122 in a rest position.

In a first embodiment, the rest position is held due to a preloading of a valve tappet 124 of the valve 122 against the smaller spring tension of the compressed spring 118. In a second embodiment, the pivoting movement of the lever arm 102 about the pivot axis 104 is blocked, braked or damped in the first state. In a third In the embodiment, the lever arm 102 is essentially held in the rest position with respect to the pivot axis 104 due to its moment of inertia, for example in that a resonance frequency or natural frequency of the resiliently coupled lever arm 102 is small compared to the speed of the cam 108. The three embodiments can be combined in pairs or completely.

In one in the Figures 3 and 4 The second state shown schematically, the pressure piston chamber 112 (optionally in its maximum extent when the shoulder 114 is in contact with the stop 116) is filled with the hydraulic fluid. In the second state of the coupling mechanism 110, the pick-up element 106 is rigidly coupled to the lever arm 112 via the hydraulic fluid, for example by a pressure of the hydraulic fluid being predetermined via a fluid connection in the pressure piston chamber 112 or by a fluid outflow from the pressure piston chamber 112 being interrupted.

Due to the rigid coupling between pickup element 106 and lever arm 102 in the second state of coupling mechanism 110, the movement of pickup element 106 following cam 108 is transmitted via lever arm 102 and actuating element 120 to valve tappet 124 of valve 122. Pivoting movement 126 about pivot axis 104 in the second state and the resulting actuation 128 of the valve 122 is in the Figures 3 and 4 shown. At the in Figure 3 The first rotational position of the cam 108 shown is the lever arm 102 in a first pivot position. At the in Figure 4 The second rotational position of the cam 108 shown, the tip of which interacts with the rigidly coupled pick-up element and guides the lever arm 102 into a second pivot position different from the first pivot position.

In each embodiment, the lever arm 102 can be designed as a rocker arm with the coupling mechanism 110 and the actuating element 120 on different partial lever arms with respect to the pivot axis 104.Alternatively, the lever arm 102 can be designed as a rocker arm, the coupling mechanism 110 and the actuating element 120 on the same side with respect to the pivot axis 104 are arranged.

Figure 5 shows schematically a second exemplary embodiment of the valve drive lever 100 with a control unit 130 for the optional control of the first and second states of the coupling mechanism 110. Equivalent or interchangeable features of the second exemplary embodiment are given the same reference symbols as in FIGS Figures 1 to 4 of the first embodiment Mistake. The control unit 130 of the second exemplary embodiment can be combined with any further exemplary embodiment.

The control unit 130 comprises a check valve 132 with a closing element 134, which opens in the inflow direction to the pressure piston chamber 112 and closes in the outflow direction from the pressure piston chamber 112. The control unit 130 further comprises a control piston chamber 136 (for example in a cylinder) in which a control piston 138 is arranged to be longitudinally movable. The control piston 138 delimits the control piston chamber 136 with an input-side active surface 140. An output side of the control piston 138 opposite the input-side active surface 140 is in fluid communication with the pressure piston chamber 112 via a fluid connection 144. On the output side is the control piston 138 or a closing element adjacent to the control piston 138 designed to close the cross section of a valve seat via an output-side active surface 142.

The input-side effective area 140 (for example with _a cross-sectional area A) is greater than the output side effective area 142 (e.g., with cross-sectional area A _of). Is the input-side effective area 140 by a standing with the control piston chamber 136 in fluid communication control line 146 is pressurized (for example with a control pressure P _Control) that caused by the control pressure force of the control piston 138 in its longitudinal direction of motion corresponds to (for example, the force A _a · p _tax) a greater closing pressure p _connected to the output side effective area 142 (e.g., a ratio a _a / a _of the input-side effective area 140 for larger output side effective area of 142 closing pressure).

The pressure piston chamber 112 can be filled with hydraulic fluid during the transition from the first state to the second state of the coupling mechanism 110 via the check valve 132, which is also connected to the control line 146 on the inlet side. A control pressure psteuer in the control line 146 is sufficient to maintain by means of the control piston 138 a greater ratio of the active surfaces 140 and 142 closing pressure p _closing = p _tax · A _a / _A in the plunger chamber 112 to the rigid coupling of the Abgriffselements 106th

Without the application of pressure to the control piston chamber 136 via the control line 146, the control piston 138 assumes an open position. In the open position, the output-side fluid connection 144 between control unit 130 and pressure piston chamber 112 is in fluid connection with a relief line 148 for the transition from the second state to the first state of the coupling mechanism 110.

The in Figure 5 The illustrated embodiment of the control unit 130, the check valve 132 and the control piston 138 are each in fluid connection on the inlet side and on the outlet side, ie check valve 132 and the control piston 138 in the control piston chamber 136 are connected in parallel. The input side of the control unit 130 is in fluid connection with the control line 146. The output side of the control unit 130 is connected to the pressure piston chamber 112 via a single fluid connection 144. In a variant of the control unit 130, which can be used in any exemplary embodiment, the check valve 132 and the control piston 138 are connected on the output side to the pressure piston chamber 112 via separate fluid connections.

The control line 146 is preferably connected to an existing lubricating oil supply of the internal combustion engine via a solenoid valve for controlling the first and second states of the coupling mechanism 110.

Figure 6 FIG. 13 shows a perspective illustration of a third exemplary embodiment of the valve drive lever 100. In FIG Figure 6 The third exemplary embodiment shown, the control unit 130 is arranged on the coupling mechanism 110. The control unit 130 is preferably arranged on the side of the pick-off element 106 facing away from the cam 108 in the longitudinal direction of movement (ie, the transverse direction to the lever arm 102). In particular, the direction of longitudinal movement of the pick-up element 106 and the direction of longitudinal movement of the control piston 138 can be coaxial and / or the fluid connections between the control piston 138 and the pressure piston chamber 112 can be implemented through a bore within a common housing of the coupling mechanism 110 and the control unit 130.

The pivot axis 104 is mounted such that it can pivot via a bearing block 152 screwed to the cylinder head of the internal combustion engine. The control line 146 is guided through bores within the lever arm 102 and is in fluid connection with the solenoid valve for controlling the first and second states of the coupling mechanism 110 via the pivot axis 104, regardless of the pivot position of the lever arm 102.

In an in Figure 6 The first variant shown comprises the lever arm 102 between the pivot axis 104 and the actuating element 120 a double web 154. Between the webs 154 there is free space for connections of an injection nozzle 156 of the internal combustion engine. In a second variant, which can be implemented in any exemplary embodiment, the lever arm 102 is guided over the injection nozzle 156.

Figure 7 shows schematically a cross section of the third exemplary embodiment of the valve drive lever 100 in the swivel plane of the swivel axis 104. Oil from the engine oil circuit is constantly fed to the rocker arm 102 via a bore in a permanent oil pressure line 158. When the engine is in operation, oil pressure is always applied to the permanent oil pressure line 158 in order to lubricate a roller tappet 160 of the pick-up element 106 as it moves up and down on the cam 108. The control line 146 implemented by bores in the rocker arm 102 is also supplied with the oil from the motor circuit, preferably via a solenoid valve connected upstream, which optionally supplies oil via the pivot axis 104 to control the first and second states of the coupling mechanism 110.

The first and second states of the coupling mechanism 110 can also be referred to as the switched-off or switched-on state with regard to the function of the valve 122 for removing the compressed gas (for example compressed air). In the switched-on state, oil pressure is therefore present in the bore of the control line 146. The oil pressure forces a ball as a closing element 134 out of the check valve 132 formed by a countersink and allows the oil to flow into the pressure piston chamber 112 via a short bore as a fluid connection 144-1. At the same time, the oil flows into the control piston chamber 136 and presses the control piston 138-1 (which defines the active surface on the input side) against a ball as a closing element 138-2 with the active surface on the output side. The closing element 138-2 closes the fluid connection 144-2 between the pressure piston chamber 112 and the relief line 148. The pressure piston chamber 112 is thus a closed chamber and a pressure piston 162 of the pick-up element 106 is pressed away from the lever arm 102 towards the cam 108. The pressure piston 162 always rests on the roller tappet 160.

The anti-rotation lock 116 formed by a protruding screw shaft comprises a protrusion which engages in a longitudinal groove on the pressure piston 162. Optionally, the projection also serves as a stop, the upper end of the groove forming the shoulder 114.

The roller tappet 160 is thus rigidly coupled to the lever arm 102 on the cam 108, and the entire rocker arm 102 is moved by the cam 108 to actuate 128 the valve 122 due to the rigid coupling.

At the same time, preferably through a fluid connection with the control line 146, oil pressure is also present in a controlled oil pressure line 164 for supplying the actuating element 120 with lubricating oil. The actuating element 120 comprises a spherical head connection 166 and an actuating surface 168, each of which is wetted with lubricating oil via the controlled oil pressure line 164 will. Oil is only delivered in the controlled oil pressure line 164 when the coupling mechanism 110 is in the second state, that is to say the rocker arm 102 is in the switched-on state, with the solenoid valve open.

In the first state (i.e. in the switched-off state) the oil supply into the control line 146 (and the controlled oil pressure line 164 in fluid communication therewith) is interrupted via the solenoid valve. This means that there is no longer any pressure on the control piston 138-1 and the fluid connection 144-2, which is designed as a relief bore, is no longer closed via the control piston 138-1 and its closing element 138-2 on the active surface 142 on the output side. The open position of the closing element 138-2 brings the fluid connection 144-2 into connection with the relief line 148. The roller tappet 160 is pressed towards the lever arm 102 together with the pressure piston 162 due to the actuation by the cam 108. The pressure piston 162 pushes the oil out of the pressure piston chamber 112 via the fluid connection 144-2 into the relief line 148. Since there is no longer any pressure in the pressure piston chamber 112 and no longer acts on the pick-up element 106 via the pressure piston 162, the roller plunger 160 of the pick-up element 106 is only pressed via the compression spring 118 onto the cam 108 in accordance with the resilient first state of the coupling mechanism 110. That is, the roller tappet 160 and the pressure piston 162 of the pick-up element 106 move up and down, but not the entire valve drive lever 100, for example because the spring force of the compression spring 118 is less than the pressure force of a valve spring of the valve 122, which is on the opposite side of the Lever arm 102 cooperates with the actuating element 120.

The actuator may further include an adjustment screw 170. As an alternative or in addition, a valve clearance of the valve 122 can be set by the fluid volume in the pressure piston chamber 112 in the second state.

Figure 8 shows an enlarged detail of the cross section of FIG Figure 7 . A bearing bush 172 is arranged between the pivot axis 104 and a bore in the lever arm 102. In each exemplary embodiment, oil (for example, permanently during operation of the internal combustion engine) can be fed into the oil pressure line 158 and / or (for example, to control the state of the coupling mechanism 110 optionally) into the control line 146 via the bearing bush 172. In each pivot position of the lever arm 102, azimuthal slots in the bearing bush 172 on the lateral surface of the pivot axis 104 connect the ends of the bores in the pivot axis 104 with the corresponding ends of the bores in the lever arm 102 Figure 8 The third embodiment shown is the control line 146 and the controlled oil pressure line 164 in fluid connection via bores in the pivot axis 104, so that the actuating element 120 is supplied with lubricating oil precisely when the coupling mechanism 110 is in the rigid second state.

Figure 9 shows a schematic cross section in the pivoting plane of a fourth embodiment of the valve drive lever 100. The fourth embodiment differs from the previous embodiments in the design of the coupling mechanism 110. The coupling mechanism 110 of the fourth embodiment can be used in conjunction with any of the previous embodiments. Features that are identical to or interchangeable with the above exemplary embodiments are shown in FIG Figure 9 provided with the same reference numerals.

The compression spring 118 is supported on the lever arm 102 and, instead of on the pressure piston 162 of the pick-off element 106, rests on the roller plunger 160 of the pick-off element 106. An additional counter-pressure spring 174 presses the pressure piston 162 continuously upwards (i.e. towards the lever arm 102) in the first state of the coupling mechanism 110, that is to say in the switch-off mode of the valve drive lever 100. The pressure piston 162 no longer moves up and down in the first state and thus does not cause unwanted pumping of the oil.

In the in Figure 9 The fourth exemplary embodiment shown, the counter-pressure spring 174 is supported on the pressure piston 162 and rests on the roller tappet 160. In an alternative embodiment of the coupling mechanism, the lever arm 102 and the pressure piston 162 are connected to a tension spring. As a result, in the first state, the pressure piston 162 does not lie against the roller tappet 160 and is pressed towards the lever arm 102 (ie to a minimum volume of the pressure piston chamber 112). The spring tension of the counter-pressure spring 174 of the pressure piston 162 (in any position of the pressure piston 162 and the roller tappet 160) is at most so great that when the pressure in the control line 146 and thus in the pressure piston chamber 112 (for example at 1 bar oil pressure), the pressure piston 162 to the roller tappet 160 is pressed towards and rests against this for rigid coupling in the second state of the coupling mechanism 110.

In all exemplary embodiments, the compression spring 118 ensures that the roller tappet 160 rests on the cam 108 both in the first and in the second state. The spring tension of the compression spring 118 for the roller tappet 160 is at least so great that the mass of the roller tappet 160 follows the cam 108 at the maximum speed. This improves the efficiency and reduces wear and tear and running noise.

The coupling mechanism 110 of the fourth exemplary embodiment has the advantage that the pressure piston 162 does not constantly follow the up and down movement of the roller tappet 160 in the first state of the coupling mechanism 110 (i.e. in the switch-off mode of the valve drive lever 100) and pumps oil unnecessarily. This improves the efficiency.

Figure 10 shows a perspective view of the fifth exemplary embodiment of the valve drive lever 100. The fifth exemplary embodiment differs from the preceding exemplary embodiments in the arrangement of the control unit 130. The arrangement of the control unit 130 of the fifth exemplary embodiment can be implemented accordingly in each of the preceding exemplary embodiments. Features that are identical to or interchangeable with the above exemplary embodiments are shown in FIG Figure 10 provided with the same reference numerals.

In the fifth exemplary embodiment, the control unit 130 is not arranged in the extended axis above the pressure piston 162, but at another (basically any) point, for example on the lever arm 102. The control unit 130 and the coupling mechanism 110 can (for example as in the second embodiment of FIG Figure 5 ) via a fluid connection 144 or (for example as in the fifth embodiment of FIG Figure 10 ) be connected via two fluid connections 144-1 and 144-2.

An advantageous location on the lever arm 102 for the arrangement of the control unit 130 is at the pivot axis 104 (for example above the pivot axis 104). The fifth embodiment of the Figure 10 shows an example of this arrangement. The arrangement at the pivot axis 104 results in a lower overall height. Furthermore, the inertia (ie the moment of inertia of the valve drive lever 100 with respect to the pivot axis 102) is improved. While in the Figure 10 The fifth embodiment shown is the orientation of the control unit 130 with respect to the direction of movement of the control piston 138 perpendicular to the lever arm 102, parallel to the direction of movement of the valve tappet 124 and / or parallel to the transverse direction of the lever arm, the control unit 130 can also be parallel to the lever arm 102, perpendicular to the direction of movement of the valve tappet 124 or at an angle to it. The basic functional principle does not change, only the oil holes are adapted to the location and / or orientation of the control unit 130.

Although the invention has been described with reference to exemplary embodiments, it will be apparent to a person skilled in the art that various changes can be made and equivalents used as replacements. Furthermore, many modifications can be made to suit a particular situation or situation Adapt drive to the teaching of the invention. Consequently, the invention is not limited to the disclosed exemplary embodiments and implementations, but rather encompasses all exemplary embodiments that fall within the scope of the appended claims.

List of reference symbols

100

Valvetrain levers

102

Lever arm

104

Swivel axis

106

Pick-off element

108

cam

110

Coupling mechanics

112

Plunger space

114

paragraph

116

Anti-twist device, optional stop

118

Compression spring

120

Actuator

122

Valve in the cylinder head

124

Valve lifters

126

Swivel movement

128

Actuation movement

130

Control unit

132

check valve

134

Closing element

136

Control piston space

138

Control piston

140

Effective area on the input side

142

Effective area on the output side

144

Fluid connection between control unit and coupling mechanism

146

Control line

148

Discharge line

152

Bearing block

154

Double bridge

156

Injector

158

Permanent oil pressure line

160

Roller tappet

162

Plunger

164

Controlled oil pressure line

166

Ball joint

168

Operating area

170

Adjusting screw

172

Bearing bush

174

Counter pressure spring

Claims (12)

1. A valve train lever (100) for actuating a valve (122) of a reciprocating piston engine, in particular an internal combustion engine, comprising:

   a lever arm (102), which is pivotally movable about a pin (104);

   a tapping element (106), which lies against or can be made to lie against a cam (108) of a camshaft of the reciprocating piston engine, wherein the tapping element (106) is arranged movably in a transverse direction, transversely in relation to the lever arm (102) ;

   a coupling mechanism (110), by way of which the tapping element (106) is coupled to the lever arm (102) spring-elastically in a first state and rigidly in a second state, wherein the coupling mechanism (110) comprises a pressure piston space (112) and a pressure piston (162) that is movable in the transverse direction and delimits the pressure piston space (112);

   an actuating element (120), which is connected to the lever arm (102) and lies against or can be made to lie against a valve tappet (124) of the valve (122); and

   a control unit (130) for controlling the first state and the second state of the coupling mechanism (110), wherein the control unit (130), on the outlet side, is in fluid connection (144) with the pressure piston space (112), wherein the control unit (130), on the inlet side, is in fluid connection with a control line (146), wherein the control unit (130) is designed to, in the first state, connect the outlet-side fluid connection (144) to the pressure piston space (112) with a relief line (148),

   characterized in that,

   for realizing a pressure intensification, the control unit (130) comprises a control piston (138) with an inlet-side effective surface (140) and an outlet-side effective surface (142), which is smaller than the inlet-side effective surface (140).
2. The valve train lever according to Claim 1, wherein, at least in the second state, the pressure piston (162) interacts with the tapping element (106) and, in the second state, the pressure piston space (112) is filled with a hydraulic fluid.
3. The valve train lever according to Claim 1 or 2, wherein the coupling mechanism (110) comprises a pressure spring (118), which is supported on the lever arm (102) and prestresses the tapping element (106) in the transverse direction.
4. The valve train lever according to Claim 3, wherein the pressure piston (162) interacts with the tapping element (106) in the first state and in the second state, and the pressure spring (118) is arranged in the pressure piston space (112) and lies against the pressure piston (162).
5. The valve train lever according to Claim 3, wherein the pressure spring (118) lies against the tapping element (106).
6. The valve train lever according to Claim 5, wherein the coupling mechanism (110) comprises a counterpressure spring (174), which is supported on the tapping element (106) and prestresses the pressure piston (162) in the transverse direction, and, in the first state, the tapping element (106) is kept at a distance from the pressure piston (162) in the transverse direction.
7. The valve train lever according to one of Claims 1 to 6, wherein the tapping element (106) comprises a roller tappet (160).
8. The valve train lever according to one of Claims 1 to 7, wherein the control unit (130) is arranged on the coupling mechanism (110) or on a pivot bearing of the pivotally movable lever arm (102).
9. The valve train lever according to one of Claims 1 to 8, wherein the tapping element (106) is arranged immovably in a longitudinal direction transverse in relation to the transverse direction.
10. A reciprocating piston engine, in particular an internal combustion engine, with a valve train lever (100) according to one of Claims 1 to 9.
11. The reciprocating piston engine according to Claim 10, wherein the control unit (130) is optionally in fluid connection (146) on the inlet side with the oil circuit of the reciprocating piston engine by way of a solenoid valve.
12. A motor vehicle, in particular a commercial vehicle, with an internal combustion engine according to Claim 10 or 11.

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