DE102015223565A1 - Switchable cam follower of a valve train - Google Patents

Abstract

The invention relates to a switchable drag lever (1), which in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem (9a, 9b) at least one gas exchange valve (8a, 8b) and at least one supporting element (5a, 5b) mounted on a motor housing. is arranged, and the one outer lever (2) and an inner lever (3), wherein the outer lever (2) or the inner lever (3) at one end at least one receptacle (4a, 4b) for a head (6a, 6b) of Supporting element (5a, 5b) and at the other end at least one contact surface (7) for the valve stem (9a, 9b) of a gas exchange valve (8a, 8b), wherein the outer lever (2) and the inner lever (3) are hinged together wherein the outer lever (2) or the inner lever (3) is loaded via at least one pressure spring in the direction of the camshaft, and in which the outer lever (2) and the inner lever (3) kop kop by means of a coupling device with each other pelbar and decoupled. In order to be able to carry out the coupling and decoupling of the two levers (2, 3) at the same actuating speed, the invention provides that the coupling device is designed as a hydraulic actuating cylinder (18) which is effective in two axial directions.

Description

The invention relates to a switchable drag lever, which is arranged in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem of at least one gas exchange valve and at least one support member mounted on a motor housing, and having an outer lever and an inner lever, and according to further features of the preamble of independent claims 1 to 3.

The valve train of an internal combustion engine has the function of transmitting the lift of the cams of a camshaft to the gas exchange valves, that is to open and close the intake and exhaust valves of the internal combustion engine according to the Hubverläufen the respective cam tracks. The geometry of the cam tracks can each be tapped via a drag lever and transmitted to the associated gas exchange valve as actuating movement, which is supported at one end via a support member to a housing of the internal combustion engine, such as the engine housing or cylinder head, and at the other end with the shaft end the associated gas exchange valve is in contact. The tap of the geometry of the cam tracks can be carried out in the form of a Gleitabgriffs via a sliding contact attached to the rocker arm or integrally molded shoe or in the form of a Rollenabgriffs by means of a Wälzkontakts a rotatably mounted on the rocker roller. Switchable drag levers of the type mentioned can be used in conjunction with a cylinder deactivation to deactivate gas exchange valves or in the context of a variable valve train for Hubumschaltung of gas exchange valves.

Such switchable drag levers may be formed in different variants, wherein in a first variant, the at least one support element and the at least one valve stem are supported on the outer lever, while in a second variant, said component are supported on the inner lever. For cam follower variants, application-specific advantages, their structure and mode of action are largely identical.

When used in an internal combustion engine with cylinder deactivation, it may be advantageous to provide the inner lever of the finger lever with a tapping element, such as a shoe or a roller. The stroke of the associated cam is transmitted to the relevant gas exchange valve only in the coupled state of the inner lever with the outer lever. In the decoupled state of the inner lever leads due to the contact with the associated cam while a pivoting movement, but springs against the outer lever, so that no lifting movement is transmitted to the gas exchange valve. The relevant cylinder of the internal combustion engine is then switched off. Usually, the coupling pin of the finger lever is held in a cylinder-stop internal combustion engine by means of a compression spring in a locking position, in which the inner lever is coupled to the outer lever, and is displaced by means of oil pressure in an unlocked position, in which the inner lever is decoupled from the outer lever. Different versions of such rocker arms are for example from the US 5 544 626 A , of the DE 10 2004 039 503 A1 and the DE 10 2006 057 894 A1 known.

When used in an internal combustion engine with Hubumschaltung both the inner lever and the outer lever are each provided with a tapping element for a cam contact. In the coupled state of the inner lever with the outer lever of the stroke profile of the outer lever associated cam is transmitted to the relevant gas exchange valve. In the decoupled state, although the outer lever executes a pivoting movement under the effect of the associated cam, it springs against the inner lever, so that the stroke geometry curve of the cam assigned to the inner lever is then transferred to the gas exchange valve. The relevant cylinder of the internal combustion engine can thereby be switched depending on load and speed dependent between different Hubverläufen the gas exchange valve. Usually, the coupling pin of the finger lever is held in a Hubschalter with a compression spring in the unlocked position, in which the inner lever is decoupled from the outer lever, and is displaced by means of oil pressure in the locking position, in which the inner lever is coupled to the outer lever. Different versions of such rocker arms are for example in the DE 10 2004 051 422 A1 , of the DE 10 2006 023 772 A1 and the DE 10 2009 033 634 A1 described.

Both types of rocker arms is common that the coupling pin is moved by spring force in the one switching position (locking position or unlocking) and by means of oil pressure in the other switching position (unlocked or locked position). This inevitably different operating speeds of the coupling pin and thus different switching times of the respective finger lever between the locking position and the unlocked position of the coupling bolt result, which adversely affect the switching behavior of the valve train.

The invention is therefore based on the object to present a switchable drag lever, in which the switching of its coupling device between the locking position and the unlocked position can be carried out in both directions of adjustment with the same actuating speed.

To achieve this object, the invention is based on a switchable drag lever, which is arranged in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem at least one gas exchange valve and at least one supporting element mounted on a motor housing, and having an outer lever and an inner lever, wherein the outer lever or the inner lever at one end has at least one receptacle for a head of the support element and at the other end at least one contact surface for the valve stem of a gas exchange valve, wherein the outer lever and the inner lever are hinged together, wherein the outer lever or the inner lever via at least one pressure spring is loaded in the direction of the camshaft, and in which the outer lever and the inner lever by means of a coupling device can be coupled together and decoupled. In this drag lever is now provided that the coupling device is designed as an effective in two axial directions hydraulic actuating cylinder.

The term actuating cylinder is understood to mean a piston-cylinder arrangement. The cylinder is fastened or formed on the inner lever or on the outer lever, and its piston can engage in and out of a locking opening in the other lever. Characterized in that the actuation of this actuating cylinder takes place in both, axially opposite actuating directions in each case by means of a hydraulic pressure, the locking and unlocking of the two levers of the finger lever can be carried out with the same actuating speed.

The object is achieved with a drag lever with the features of the preamble of claim 2, wherein the outer lever for conditioning the at least one valve stem and the at least one support member, achieved in that for switching the coupling bolt between a locking position and an unlocking a double-acting hydraulic Actuating cylinder is provided with a piston attached to a piston rod, which is arranged in or on the outer lever, the piston rod is rigidly connected to the coupling pin, and the piston separates two pressure chambers of the actuating cylinder, which can be connected to adjust the coupling bolt alternately with an oil pressure source or are depressurized switchable.

The same problem is solved in a drag lever with the features of the preamble of claim 3, wherein the inner lever for conditioning the at least one valve stem and the at least one support member, achieved by switching a double-acting hydraulic between a locking position and an unlocked position for switching the coupling pin Actuating cylinder is provided with a piston attached to a piston rod, which is arranged in or on the inner lever, wherein the piston rod is rigidly connected to the coupling pin, and the piston separates two pressure chambers of the adjusting cylinder, which alternately connectable for adjusting the coupling bolt with an oil pressure source or depressurized switchable.

Advantageous embodiments and further developments of the drag lever according to the invention are the subject of the dependent claims and / or are mentioned below.

Accordingly, according to the first detailed rocker arm variant, the invention is based on a switchable rocker arm of a valve drive which is arranged in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem of at least one gas exchange valve and at least one support element mounted on a motor housing, and having a frame-shaped outer lever and a rod-shaped inner lever. The outer lever has at one end at least one receptacle for a head of the support element and at the other end at least one contact surface for the valve stem of a gas exchange valve. The inner lever is disposed within the outer lever and hinged to this end, loaded via at least one contact pressure in the direction of the camshaft, and a cylindrical coupling pin, which is guided axially displaceably in a longitudinal bore of the outer lever, by a positive engagement in or under an end Projection of the inner lever coupled to the outer lever.

In order to move the coupling pin between the locking position and the unlocking position in both directions of adjustment at the same speed and thus to allow the same switching times for locking and unlocking the finger lever is provided according to the invention that for switching the coupling pin between a locking position and an unlocked position a double-acting hydraulic actuating cylinder is provided with a piston attached to a piston rod, which is arranged in or on the outer lever, wherein the piston rod is rigidly connected to the coupling pin, and whose pistons two pressure chambers of the Adjusting cylinder separates from each other, which are connected to adjust the coupling bolt alternately connected to an oil pressure source or depressurized.

The actuating cylinder can be an integral part of the outer lever by the arrangement of the respective cylinder bore in the outer lever. However, it is also possible that the actuating cylinder is designed as a separate component and, for example via a screw, is attached to the outer lever. In contrast to the known switchable drag levers, in which the coupling pin is moved by means of spring force in the one switching position (locking position or unlocking) and by means of oil pressure in the other switching position (unlocking or locking position), the displacement of the coupling bolt between the locking position and the unlocking now hydraulically in both directions. With appropriate dimensioning of the effective surfaces of the piston, therefore, the same switching times for the locking and the unlocking of the finger lever can be achieved.

An inventively designed switchable drag lever according to the second, in detail going rocker arm variant is also arranged in the valve gear of an internal combustion engine between at least one cam of a camshaft and the valve stem of at least one gas exchange valve and at least one mounted on a motor housing support member. The drag lever has a frame-shaped outer lever and a rod-shaped inner lever, wherein the inner lever has at least one receptacle for a head of the support element at one end and at least one contact surface for the valve stem of a gas exchange valve at the other end. The inner lever is disposed within the outer lever and pivotally mounted at this end, and the outer lever is loaded via at least one pressure spring in the direction of the camshaft. In addition, the outer lever by means of a coupling bolt, which is guided axially displaceably in a longitudinal bore of the inner lever, coupled by a positive engagement in or under an end projection of the outer lever with the inner lever.

To solve the task is provided with this rocker arm that is provided for switching the coupling bolt between a locking position and an unlocking position a double-acting hydraulic actuator cylinder with a piston rod fixed to a piston, which is arranged in or on the inner lever, wherein the piston rod rigid with the coupling pin is connected, and the piston separates two pressure chambers of the adjusting cylinder from each other, which are connected to adjust the coupling bolt alternately connected to an oil pressure source or depressurized.

Accordingly, the two-way hydraulic switching device can be used with great advantage in the two variants presented switchable drag lever.

To simplify the production is advantageously provided that the coupling pin is integrally connected to the piston rod of the actuating cylinder, and that the coupling pin and the piston rod have identical diameter. The piston rod of the actuating cylinder thus passes directly into the coupling pin, or in other words, the coupling pin is designed as an axial extension of the piston rod of the actuating cylinder.

The piston of the adjusting cylinder is preferably formed circular disk-shaped and has, for example, a central bore, via which the piston is positively, positively or materially secured to the piston rod. The piston may, for example, be screwed or pressed onto the piston rod, or be welded to the piston rod. However, it is preferably provided that the coupling pin, the piston rod and the piston are integrally formed and are made, for example, as a rotating part.

To improve the bearing of the piston, the actuating cylinder on the side facing away from the coupling pin advantageously a coaxially arranged second piston rod which is integrally connected to the first piston rod and axially movable in a coaxial second longitudinal bore of the inner lever, the outer lever or a separate housing is performed. As a result, the coupling pin is guided over the storage of the second piston rod particularly stable against tilting, and jamming of the coupling pin is largely excluded. In addition, this synchronization is possible.

Despite the hydraulic adjustability of the coupling bolt, it is advantageous if in at least one of the two pressure chambers effective as a compression spring return spring is arranged, which is arranged between a bottom wall of the actuating cylinder and the piston. This return spring is used to press the coupling pin when the internal combustion engine and thus unpressurized pressure chambers of the actuating cylinder in the switching start position provided for the engine start (locking position or unlocking position). Such a return spring therefore preferably has a relatively low spring stiffness.

The diameters of the first piston rod and the second piston rod are preferably made the same size, as this results in the piston the actuating cylinder on both sides equal large effective areas and thus equal in both directions Stellstellkräfte and actuating speeds result.

However, it is also possible that the diameters of the first piston rod and the second piston rod are made different sizes. The thus on the piston of the actuating cylinder on both sides differently sized effective surfaces and thus in both directions of adjustment different sized actuating forces can be used to compensate for different levels of resistance forces when loading and unloading the coupling pin from or into the inner lever.

In particular, when the actuating cylinder has a single return spring with higher spring stiffness, preferably that piston rod, on whose side the return spring is arranged, a larger diameter than the other piston rod, on whose side no return spring is arranged. Due to the larger diameter of the piston rod, the associated active surface of the piston is reduced, whereby the sum of hydraulic force and spring force to the height of the purely hydraulic actuating force acting in the opposite direction on the piston, can be adjusted.

By a proper choice of the diameter of the two piston rods and the piston same or different actuating speed for the two operating directions of the here simplistic actuating cylinder said piston-cylinder arrangement can be set freely within wide limits. For example, individual, user-specific requirements with respect to the actuating speed of the piston in the two actuating directions may even require that no second piston rod be arranged in the actuating cylinder. A corresponding adjustment of the actuating cylinder by using a preferably one-piece component of coupling pin, the first piston rod and piston is easily possible.

In a double support of the finger lever, the supply and removal of pressure oil in the pressure chambers or from the pressure chambers of the actuating cylinder according to a development of the invention via one of the support elements takes place. About an oil hole in the bearing head of a support element and a connection channel pressure oil is then fed to the one pressure chamber of the actuating cylinder or discharged therefrom, and via an oil hole in the bearing head of the other support element and a connection channel pressure oil is discharged from the other pressure chamber of the actuating cylinder or this fed.

For controlling the switching of the coupling bolt between the locking position and the unlocking position, a 4/2-way magnetic switching valve can be arranged, via which the pressure chambers of the actuating cylinder are alternately connected to the oil pressure source connectable or depressurized.

Alternatively, however, two 3/2-way magnetic control valves or other valve combinations may be arranged to control the switching of the coupling pin between the locking position and the unlocking position, via which the pressure chambers of the actuating cylinder are alternately connected to the oil pressure source or depressurized switchable.

Especially when the actuating cylinder has a single return spring is to control the switching of the coupling pin between the locking position and the unlocked position preferably a 4/3-way magnetic switching valve, via which the pressure chambers of the actuating cylinder in a central rest position of the solenoid valve both switchable and without pressure in external switching positions of the solenoid valve alternately with the oil pressure source can be connected or switched without pressure. The use of such a 4/3-way magnetic switching valve ensures that both pressure chambers of the actuating cylinder vented in energized solenoid valve and thus the piston of the actuating cylinder or the coupling pin under the action of the return spring safely moved to its intended for engine start rest position and in this is held.

Alternatively, two 3/2-way solenoid valves or other valve combinations may be arranged in the latter design of the finger lever to control the switching of the position of the coupling bolt between the locking position and the unlocking position, via which the pressure chambers of the actuating cylinder alternately connected to the oil pressure source or depressurized switchable.

To further illustrate the invention, the description is accompanied by a drawing with several embodiments. In this shows

1 a switchable rocker arm of a valve train with an actuating device according to the invention for a coupling bolt in the locked state in a partially unwound horizontal longitudinal section,

2 the switchable drag lever of a valve train according to 1 in the unlocked state in a partially unwound horizontal longitudinal section,

3 a switchable drag lever in a first embodiment of the Actuating device of the coupling pin in an enlarged section of a horizontal longitudinal section,

4 a switchable drag lever with a second embodiment of the actuating device of the coupling bolt in an enlarged section of a horizontal longitudinal section,

5 the switchable drag lever of a valve train according to 3 with a first valve arrangement for actuating the actuating device of the coupling bolt,

6 the switchable drag lever of a valve train according to 3 with a second valve arrangement for actuating the actuating device of the coupling bolt,

7 the switchable drag lever of a valve train according to 4 with a third valve arrangement for controlling the actuating device of the coupling bolt, and

8th the switchable drag lever of a valve train according to 4 with a fourth valve arrangement for controlling the actuating device of the coupling bolt.

One in the 1 and 2 each in a partially developed horizontal longitudinal section shown switchable rocker arm 1 a valve train according to the initially mentioned first design has a frame-shaped outer lever 2 and a rod-shaped inner lever 3 on. The outside lever 2 has two dome-shaped receptacles at one end 4a . 4b for each a spherical head 6a . 6b of two support elements 5a . 5b and at the other end a sliding surface 7 for contact with two valve stems 9a . 9b of two gas exchange valves 8a . 8b on. The inner lever 3 is largely within the outer lever 2 arranged and at its valve end via an axis 10 pivotally mounted on this. At its support element end, the inner lever 3 a web-shaped projection 11 with one in the 1 and 2 unrecognizable arcuate contact surface. About at least one presently not shown pressure spring is the inner lever 3 in the direction of an associated cam one above the finger lever 1 or the drawing plane arranged camshaft loaded, so that a tap element 12 of the inner lever 3 as present by means of an axis 13 rotatably mounted roller is formed, is constantly in contact with the cam track of the respective cam.

For mechanical coupling and decoupling of the inner lever 3 with the outside lever 2 is the outside lever 2 with a cylindrical longitudinal bore 14 provided in a cylindrical coupling pin 15 is guided axially movable. The coupling pin 15 can have a flattened contact portion at its free axial end.

In 1 is the coupling pin 15 in a locking position 16 , in which the free end of the coupling pin 15 under the end projection 11 of the inner lever 3 engages, causing a pivoting of the inner lever 3 in the outer lever 2 is positively prevented, and the inner lever 3 thus with the outside lever 2 is coupled. In 2 is the coupling pin 15 in an unlocked position 17 , in which the free end of the coupling pin 15 outside the end-side projection 11 of the inner lever 3 lies, causing a pivoting of the inner lever 3 in the outer lever 2 possible, and the inner lever 3 thus from the outside lever 2 is decoupled.

For switching the coupling bolt 15 between the locking position 16 and the unlocking position 17 is a double-acting hydraulic actuator cylinder 18 with one on a piston rod 19 attached pistons 20 available. The actuating cylinder 18 is present within the outer lever 2 arranged. The piston rod 19 of the adjusting cylinder 18 is integral with the coupling pin 15 connected and goes on the of the coupling pin 15 turned away side into a second piston rod 21 above. The second piston rod 21 is in a coaxial second longitudinal bore 22 of the outer lever 2 guided axially movable. The piston 20 of the adjusting cylinder 18 is circular disk-shaped and has a central bore 46 on, over which the piston 20 positive, positive or cohesive on the piston rod 19 is attached. A one-piece design of pistons 20 , first piston rod 19 and second piston rod 21 , For example, as a rotating part, may be more advantageous. The piston 20 separates two pressure chambers 23 . 24 of the adjusting cylinder 18 from each other, each of which has a connection channel 25 . 26 in each case one of the dome-shaped shots 4a . 4b of the outer lever 3 leads, and the adjustment of the coupling pin 15 alternately with an oil pressure source connectable or can be switched without pressure.

In 1 is above the marked directional arrows 27a . 27b . 27c the outflow of pressure oil from the first pressure chamber 23 of the adjusting cylinder 18 via the assigned connection channel 25 and the first support element 5a in a non-illustrated collection container and on the indicated direction arrows 28a . 28b the inflow of pressure oil from a non-illustrated oil pressure source via the second support element 5b and the associated connection channel 26 in the second pressure chamber 24 of the adjusting cylinder 18 clarified. This is the coupling pin 15 according to the directional arrow 29 in the illustrated locking position 16 displaceable.

In 2 is above the marked directional arrows 30a . 30b . 30c the inflow of pressure oil from the not shown oil pressure source via the first support element 5a and the associated connection channel 25 in the first pressure room 23 of the adjusting cylinder 18 and over the indicated directional arrows 31a . 31b the outflow of pressure oil from the second pressure chamber 24 of the adjusting cylinder 18 via the assigned connection channel 26 and the second support element 5b illustrated in the not shown collecting container. This is the coupling pin 15 according to the directional arrow 32 in the illustrated unlocking position 17 displaceable.

To the construction of the double-acting actuator cylinder 18 to clarify further, is the drag lever 1 according to the 1 and 2 in 3 in a simplified form as well as in an enlarged detail. The coupling pin 15 , the first piston rod 19 and the second piston rod 21 are by a cylindrical bolt 33 formed with constant diameter. The diameter D _{1 of} the coupling pin 15 , the diameter D _{2 of} the first piston rod 19 and the diameter D _{3 of} the second piston rod 21 are thus identical, whereby the production of the bolt and the longitudinal bores 14 . 22 is considerably simplified. Because of the identical diameter D ₂ , D _{3 of} the piston rods 19 . 21 arise on the piston 20 on both sides identical active surfaces, which in the alternate filling of the pressure chambers 23 . 24 with pressure oil and the ventilation of the other pressure chamber 24 . 23 in both directions 29 . 32 Equal large hydraulic actuating forces on the piston 20 and consequently the same actuating speeds of the coupling bolt 15 have as a consequence.

In 4 Similarly, the construction of a double-acting actuator cylinder 18 ' represented, the structure of which is the actuating cylinder 18 according to 3 by a return spring 34 and a stepped bolt 33 ' different. The return spring 34 is effective as a compression spring and designed as a helical spring. The return spring 34 is exemplary in the second pressure chamber 24 of the adjusting cylinder 18 ' coaxial over the second piston rod 21 ' between the relevant bottom wall 47 of the adjusting cylinder 18 ' and the piston 20 arranged. The coupling pin 15 , the first piston rod 19 and the second piston rod 21 ' are now through a single stepped cylindrical bolt 33 ' educated. While the diameter D ₁ , D _{2 of} the coupling pin 15 and the first piston rod 19 are identical (D ₁ = D ₂ ), the diameter D ₃ 'of the second piston rod 21 ' made larger (D ₃ '> D ₁ = D ₂ ).

By the return spring 34 becomes the coupling pin 15 when the internal combustion engine is switched off and thus vented pressure chambers 23 . 24 in the locking position 16 pressed and held in this. Due to the enlarged diameter D3 'of the second piston rod 21 ' is the associated effective area of the piston 20 reduced accordingly, so that when hydraulic actuation of the actuating cylinder 18 ' the force in the direction 29 the locking position 16 of the coupling bolt 15 that is the sum of the spring force of the return spring 34 and the hydraulic force on the piston 20 is formed, approximately the force in the direction 32 the unlocked position 17 of the coupling bolt 15 which corresponds solely to the hydraulic force on the piston 20 is formed.

In 5 is a first valve arrangement 35.1 for hydraulic control of the actuating cylinder 18 according to 3 shown schematically. The valve arrangement 35.1 includes a 4/2-way solenoid valve 36 , about that with the connection channels 25 . 26 of the adjusting cylinder 18 connected connecting cables 37 . 38 alternately with a pressure line 41 , in by means of an oil pump 40 Pressure oil from a collection container 39 is eligible, or one in the collection container 39 leading pressureless return line 42 are connectable.

In the in 5 shown unenergized idle state of the solenoid valve 36 is the connection cable 37 of the first pressure chamber 23 with the return line 42 and the connection line 38 of the second pressure chamber 24 with the pressure line 41 connected. As a result, the first pressure chamber 23 then vented and is depressurized, and the second pressure chamber is filled with pressure oil and is pressurized, so that the coupling pin 15 in the in 5 illustrated locking position 16 is postponed and held in this.

In energized operating state of the solenoid valve 36 is the connection cable 37 of the first pressure chamber 23 with the pressure line 41 and the connection line 38 of the second pressure chamber 24 with the return line 42 connected. As a result, the first pressure chamber 23 filled with pressurized oil and is pressure-bearing, and the second pressure chamber is vented and is depressurized, so that the coupling pin 15 then in the in 5 not shown unlocking position 17 moved and held in this.

In 6 is a second valve arrangement 35.2 for hydraulic control of the actuating cylinder 18 according to 3 shown schematically. This valve arrangement 35.2 includes two 3/2-way solenoid valves 43 . 44 over which the connecting cables 37 . 38 the two pressure chambers 23 . 24 of the adjusting cylinder 18 alternately with the pressure-carrying pressure line 41 or the non-pressurized return line 42 are connectable. In the in 6 shown unenergized idle state of both solenoid valves 43 . 44 is the connection cable 37 of the first pressure chamber 23 with the return line 42 and the connection line 38 the second pressure chamber 24 with the pressure line 41 connected. As a result, the first pressure chamber 23 it is vented and is depressurized, and the second pressure chamber is filled with pressure oil and is pressurized, so that the coupling pin 15 in the in 6 illustrated locking position 16 is postponed and held in this.

In energized operating state of both solenoid valves 43 . 44 is the connection cable 37 of the first pressure chamber 23 with the pressure line 41 and the connection line 38 of the second pressure chamber 24 with the return line 42 connected. As a result, the first pressure chamber 23 filled with pressurized oil and is pressure-bearing, and the second pressure chamber is vented and is depressurized, so that the coupling pin 15 then in the in 6 not shown unlocking position 17 moved and held in this.

In 7 is a third valve arrangement 35.3 for hydraulic control of the actuating cylinder 18 ' according to 4 shown schematically. This valve arrangement 35.3 includes a 4/3-way solenoid valve 45 via which the connecting cables 37 . 38 the pressure chambers 23 . 24 of the adjusting cylinder 18 ' alternately the pressure-carrying pressure line 41 or the non-pressurized return line 42 or both with the return line 42 are connectable. In the in 7 shown unenergized idle state of the solenoid valve 45 are the connection cables 37 . 38 both pressure chambers 23 . 24 with the return line 42 connected. As a result, both pressure chambers 23 . 24 of the adjusting cylinder 18 ' thereby vented and are depressurized, so that the coupling pin 15 under the action of the return spring 34 in the in 7 illustrated locking position 16 moved and held in this.

In a first energized operating state of the magnetic switching valve 45 is the connection cable 37 of the first pressure chamber 23 with the return line 42 and the connection line 38 of the second pressure chamber 24 with the pressure line 41 connected. As a result, the first pressure chamber 23 it is vented and is depressurized, and the second pressure chamber is filled with pressure oil and is pressurized, so that the coupling pin 15 largely hydraulically in the 7 illustrated locking position 16 moved and held in this.

In a second energized operating state of the magnetic switching valve 45 with opposite polarity is the connecting cable 37 of the first pressure chamber 23 with the pressure line 41 and the connection line 38 of the second pressure chamber 24 with the return line 42 connected. As a result, the first pressure chamber 23 then filled with pressurized oil and is pressurized, and the second pressure chamber is vented and is depressurized, so that the coupling pin 15 then purely hydraulically in the in 7 not shown unlocking position 17 moved and held in this.

8th shows a fourth valve arrangement 35.4 for hydraulic control of one with a return spring 34 equipped adjusting cylinder 18 ' according to 4 , This valve arrangement 35.4 includes two 3/2-way solenoid valves 43 ' and 44 ' over which the connecting cables 37 . 38 the two pressure chambers 23 . 24 of the adjusting cylinder 18 alternately with the pressure-carrying pressure line 41 or the non-pressurized return line 42 are connectable. In the in 8th shown unenergized idle state of both solenoid valves 43 ' . 44 ' is the connection cable 37 of the first pressure chamber 23 with the return line 42 and the connection line 38 the second pressure chamber 24 with the pressure line 41 connected. As a result, the first pressure chamber 23 it is vented and is depressurized, and the second pressure chamber is filled with pressure oil and is pressurized, so that the coupling pin 15 in the in 8th illustrated locking position 16 is postponed and held in this.

LIST OF REFERENCE NUMBERS

1

 cam follower

2

 external lever

3

 internal lever

4a, 4b

 admission

5a, 5b

 supporting

6a, 6b

 head

7

 sliding surface

8a, 8b

 Gas exchange valve

9a, 9b

 valve stem

10

 Axle for inner lever

11

 Projection on the inner lever

12

 Tap element, roll

13

 Axle for the tapping element

14

 longitudinal bore

15

 coupling bolts

16

 locking position

17

 unlocking

18, 18 '

 actuating cylinder

19

 First piston rod

20

 piston

21, 21 '

 Second piston rod

22

 Second longitudinal bore

23

 First pressure room

24

 Second pressure chamber

25

 Connection channel to the first pressure chamber

26

 Connection channel to the second pressure chamber

27a-27c

 directional arrows

28a, 28b

 directional arrows

29

 Directional arrow, direction of adjustment

30a-30c

 directional arrows

31a, 31b

 directional arrows

32

 Directional arrow, direction of adjustment

33, 33 '

 bolt

34

 Return spring, coil spring

35.1

 First valve arrangement

35.2

 Second valve arrangement

35.3

 Third valve arrangement

35.4

 Fourth valve arrangement

36

 4/2-way solenoid switching valve

37

 Connecting line to the first pressure chamber

38

 Connecting line to the second pressure chamber

39

 Sump, oil sump

40

 oil pump

41

 pressure line

42

 Return line

43, 43 '

 First 3/2-way solenoid valve

44, 44 '

 Second 3/2-way solenoid valve

45

 4/3-way solenoid switching valve

46

 Central bore in the piston

47

 Bottom wall of the cylinder

D ₁

Diameter of coupling pin 15

D ₂

Diameter of the first piston rod 19

D ₃

Diameter of the second piston rod 21

D ₃ '

Diameter of the second piston rod 21 '

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• US 5544626 A [0004]
• DE 102004039503 A1 [0004]
• DE 102006057894 A1 [0004]
• DE 102004051422 A1 [0005]
• DE 102006023772 A1 [0005]
• DE 102009033634 A1 [0005]

Claims (11)

Switchable drag lever ( 1 ), which in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem ( 9a . 9b ) at least one gas exchange valve ( 8a . 8b ) and at least one supporting element mounted on a motor housing ( 5a . 5b ) is arranged, and the one outer lever ( 2 ) and an inner lever ( 3 ), wherein the outer lever ( 2 ) or the inner lever ( 3 ) at least one receptacle ( 4a . 4b ) for a head ( 6a . 6b ) of the supporting element ( 5a . 5b ) and at the other end at least one contact surface ( 7 ) for the valve stem ( 9a . 9b ) of a gas exchange valve ( 8a . 8b ), wherein the outer lever ( 2 ) and the inner lever ( 3 ) are hinged together, the outer lever ( 2 ) or the inner lever ( 3 ) is loaded via at least one pressure spring in the direction of the camshaft, and in which the outer lever ( 2 ) and the inner lever ( 3 ) can be coupled to one another and decoupled by means of a coupling device, characterized in that the coupling device acts as a hydraulic actuating cylinder (2) acting in two axial directions ( 18 . 18 ' ) is trained. Switchable drag lever ( 1 ), which in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem ( 9a . 9b ) at least one gas exchange valve ( 8a . 8b ) and at least one supporting element mounted on a motor housing ( 5a . 5b ) is arranged, and the one frame-shaped outer lever ( 2 ) and a rod-shaped inner lever ( 3 ), wherein the outer lever ( 2 ) at least one receptacle ( 4a . 4b ) for a head ( 6a . 6b ) of the supporting element ( 5a . 5b ) and at the other end at least one contact surface ( 7 ) for the valve stem ( 9a . 9b ) of a gas exchange valve ( 8a . 8b ), wherein the inner lever ( 3 ) within the outer lever ( 2 ) and is articulated on this end, is loaded via at least one pressure spring in the direction of the camshaft, and by means of a coupling pin ( 15 ), which in a longitudinal bore ( 14 ) of the outer lever ( 2 ) is axially displaceably guided, by a positive engagement in or under an end projection ( 11 ) of the inner lever ( 3 ) with the outer lever ( 2 ) can be coupled, characterized in that for switching the coupling bolt ( 15 ) between a locking position ( 16 ) and an unlocking position ( 17 ) a double-acting hydraulic actuator cylinder ( 18 . 18 ' ) with one on a piston rod ( 19 ) attached pistons ( 20 ) provided in or on the outer lever ( 2 ) is arranged, wherein the piston rod ( 19 ) rigidly with the coupling pin ( 15 ), and its piston ( 20 ) two pressure chambers ( 23 . 24 ) of the adjusting cylinder ( 18 . 18 ' ), which for adjusting the coupling bolt ( 15 ) are alternately connectable to an oil pressure source or depressurized switchable. Switchable drag lever, which is arranged in the valve train of an internal combustion engine between at least one cam of a camshaft and the valve stem of at least one gas exchange valve and at least one supporting element mounted on a motor housing, and which has a frame-shaped outer lever and a rod-shaped inner lever, wherein the inner lever at one end at least one Recording for a head of the support element and at the other end at least one contact surface for the valve stem of a gas exchange valve, wherein the inner lever disposed within the outer lever and is hinged thereto end, wherein the outer lever is loaded via at least one pressure spring in the direction of the camshaft , and wherein the outer lever by means of a coupling pin, in a longitudinal bore ( 14 ) of the inner lever is axially displaceably guided by a positive engagement in or under an end projection of the outer lever with the inner lever can be coupled, characterized in that for switching the coupling bolt between a locking position and an unlocking position, a double-acting hydraulic actuating cylinder with a fixed to a piston rod Piston is provided, which is arranged in or on the inner lever, wherein the piston rod is rigidly connected to the coupling pin, and the piston separates two pressure chambers of the adjusting cylinder, which are alternately connected to the adjustment of the coupling bolt with an oil pressure source or depressurized switchable. Drag lever according to claim 2 or 3, characterized in that the coupling pin ( 15 ) in one piece with the piston rod ( 19 ) of the adjusting cylinder ( 18 . 18 ' ), and that the coupling pin ( 15 ) as well as the piston rod ( 19 ) have identical diameters (D ₁ , D ₂ ). Drag lever according to one of claims 2 to 4, characterized in that the actuating cylinder ( 18 . 18 ' ) on the of the coupling pin ( 15 ) facing away from a coaxially arranged second piston rod ( 21 . 21 ' ), which is integral with the first piston rod ( 19 ) and axially movable in a coaxial second longitudinal bore ( 22 ) of the inner lever ( 3 ) or the outer lever ( 2 ) or a separate housing is guided. Drag lever according to one of claims 2 to 5, characterized in that in at least one of the two pressure chambers ( 23 . 24 ) acting as a compression spring return spring ( 34 ) is arranged between a bottom wall of the actuating cylinder ( 18 ' ) and the piston ( 20 ) is arranged. Drag lever according to one of claims 4 to 6, characterized in that the diameter (D ₂ , D ₃ ) of the first piston rod ( 19 ) and the second piston rod ( 21 ) are made the same size, or that the diameter (D ₂ , D ₃ ') of the first piston rod ( 19 ) and the second piston rod ( 21 ' ) are executed differently sized. Drag lever according to claims 4 to 7, characterized in that the piston rod ( 21 ' ), on whose side a return spring ( 34 ) is arranged, has a larger diameter (D ₃ '> D ₂ ) than the other piston rod ( 19 ), on whose side no return spring is arranged. Drag lever according to one of claims 2 to 8, characterized in that the supply and removal of pressurized oil into the pressure chambers ( 23 . 24 ) or from the pressure chambers ( 23 . 24 ) of the adjusting cylinder ( 18 ) with a double support of the rocker arm ( 1 ) via in each case one of the support elements ( 5a . 5b ) he follows. Drag lever according to one of claims 2 to 9, characterized in that for controlling the switching of the coupling pin ( 15 ) between the locking position ( 16 ) and the unlocking position ( 17 ) a 4/2-way solenoid valve ( 36 ) is arranged, via which the pressure chambers ( 23 . 24 ) of the adjusting cylinder ( 18 ) are alternately connectable to the oil pressure source or depressurized switchable, or that for controlling the switching of the coupling pin ( 15 ) between the locking position ( 16 ) and the unlocking position ( 17 ) two 3/2-way solenoid valves ( 43 . 44 ) are arranged, over which the pressure chambers ( 23 . 24 ) of the adjusting cylinder ( 18 ) are alternately connected to the oil pressure source or depressurized switchable. Drag lever according to one of claims 5 to 9, characterized in that for controlling the switching of the coupling pin ( 15 ) between the locking position ( 16 ) and the unlocking position ( 17 ) a 4/3-way solenoid valve ( 45 ) is arranged, via which the pressure chambers ( 23 . 24 ) of the actuating cylinder (18 ') in a central rest position of the magnetic switching valve ( 45 ) both pressure-less switchable and in the outer switching positions of the solenoid valve ( 45 ) are alternately connected to the oil pressure source or depressurized switchable.

Images