Patent ID: 12253012

DETAILED DESCRIPTION

FIG.1shows an exemplary embodiment of a valve-actuating device100in a perspective representation, wherein the valve-actuating device100is designed to actuate a combustion engine valve (not shown here).

The valve-actuating device100comprises a first rocker arm210as well as a second rocker arm211, whereby the two rocker arms210,211are rotatably mounted about a preferably common rotational axis213. A pushrod220is connected, in particular operatively connected, to the first rocker arm210in order to transmit an actuating movement from the first rocker arm210and/or second rocker arm211to the valve. Instead of rocker arms, the invention can also be implemented with other transmission elements, e.g., rocker beams. It should be understood that “rocker arm” and “finger follower” are interchangeable for purposes of the present disclosure. For example, the first rocker arm210may be considered a first finger follower210and the second rocker arm211may be considered a second finger follower211, for purposes of the present disclosure.

The first rocker arm210is designed to mark a contour of a first cam214, the second rocker arm211is designed to mark a contour of a second cam215. The two cams214,215are rotatably mounted on an, in particular common, shaft216. Preferably, the first cam214has a different contour than the second cam215in the circumferential direction of the shaft216and/or the cam lobes are circumferentially offset from one another.

The first rocker arm210and the second rocker arm211are connected together via a coupling apparatus10. The coupling apparatus10is in particular configured to transmit an actuating movement from the second rocker arm211to the first rocker arm210when the coupling apparatus10is in a blocked state or to convert a movement of the second rocker arm211into a so-called lost motion movement when the coupling apparatus10is in an unblocked state.

In the exemplary embodiment as shown, the coupling apparatus10is arranged on the second rocker arm211or a component of the second rocker arm211respectively. Preferably, a longitudinal axis A (seeFIG.3) of the coupling apparatus10, along which the length of the coupling apparatus10is adjustable, lies tangential to a trajectory of the second rocker arm211about the rotational axis. The longitudinal axis A substantially runs along or respectively parallel to a radial direction with respect to the shaft216.

The first rocker arm210in particular has a coupling section217which preferably extends into the trajectory of the second rocker arm211and is operatively connected to the second rocker arm211or coupling apparatus10respectively for transmitting the actuating movement, for example via a second coupling element12which is attachable and adjustable in the coupling section217via a lock nut221.

For lengthwise adjustment, the coupling apparatus10preferably comprises a first coupling element11(not shown inFIG.1—see e.g.,FIG.3) as well as a preferably sleeve-shaped locking element13B. In a first position, which corresponds to the above-described unblocked state of the coupling apparatus10, the coupling element11and the locking element13B are axially displaceable, preferably telescopically, along the longitudinal axis A of the coupling apparatus10relative to one another.

In order to switch the coupling apparatus10between the unblocked state and the blocked state, the locking element13B can be pivoted preferably circumferentially about the longitudinal axis of the coupling apparatus10and thus at least into the first position corresponding to the unblocked state and a second position corresponding to the blocked state of the coupling apparatus10. The relative displacement of the first coupling element11(FIG.3) and the locking element13B is blocked along the longitudinal axis A and the coupling apparatus10is thus in the blocked state when the locking element13B is in the first position, hereinafter referred to as the blocking position. Accordingly, when the locking element13B is in the second position, hereinafter referred to as the unblocking position, the relative displacement of the first coupling element11and the locking element13B along the longitudinal axis A is enabled, the coupling apparatus10thus being in the unblocked state.

The locking element13B preferably has a radially outwardly extending tappet13A which serves in actuating the locking element13B by means of a switching device110. In particular, the tappet13A extends in the radial direction with respect to the longitudinal axis A of the coupling apparatus10or runs substantially normal to said longitudinal axis A respectively. Preferably, the locking element13B forms a locking apparatus with the tappet13A. The tappet13A is preferably arranged so as to interact with a link85of a slotted guide element84of the switching device110of preferably corresponding design to tappet13A.

The switching device110is thereby mounted independently of the rocker arms210,211and preferably in fixed mounting to the housing of the combustion engine with the controlled valves (neither shown). The switching device110is preferably operated hydraulically or electromechanically by means of an actuator (not shown) and further preferably controlled by a controller (ECU) of a combustion engine.

A locking disk112is connected to the shaft216in rotationally fixed manner. As will be explained later, this serves in blocking or enabling an actuating of the coupling apparatus10by the switching device110.

FIG.2shows a plan view onto the side of the valve-actuating device100of the exemplary embodiment according toFIG.1opposite from the rotational axis213.

The first rocker arm210is shown on the left-hand side of theFIG.2illustration. A first path F1of the force transmission, depicted as a solid arrow, from the first cam214to the first rocker arm210to the pushrod220via a first pick-up218preferably runs substantially parallel to a direction of movement of the first rocker arm210.

The second rocker arm211is shown on the right-hand side ofFIG.2. Force is only transmitted from the second rocker arm211to the first rocker arm210when the coupling apparatus10is in the blocked state. When the coupling apparatus10is in the blocked state, a second path F2of the force transmission from the second cam215and the second rocker arm210to the coupling apparatus10via a second pick-up219runs substantially parallel to a direction of movement of the second rocker arm211. The second path F2of force transmission from the coupling apparatus10runs to the first rocker arm210and to the pushrod220preferably via coupling section217, in particular substantially perpendicular to the movement axis of the second rocker arm211.

It follows from the foregoing that path F1is always enabled in the embodiment as shown. Path F2, on the other hand, is activated selectively depending on the state of the coupling apparatus10.

FIG.3shows a sectional view of an embodiment of the second rocker arm211of the valve-actuating device100in the I-I plane fromFIG.2in which lies the central axis A of the coupling apparatus10. As already explained to some degree with reference toFIG.1and now fully evident inFIG.3, the coupling apparatus10comprises the first coupling element11, the locking element13B with tappet13A and additionally a second coupling element12.

The first coupling element11is fixed in force-transmitting manner to the second rocker arm211, the second coupling element12is fixed in force-transmitting manner to the first rocker arm210, preferably to its coupling section217, further preferably screwed in by means of a thread and/or secured or respectively adjustable in terms of its position relative to the first coupling element11or the locking element13B by a lock nut221.

In this exemplary embodiment, the locking element13B thereby engages completely around the first coupling element11; i.e., the locking element13B is of circumferentially closed configuration in this exemplary embodiment of a coupling apparatus10according to the invention.

FIG.4shows a detail of a sectional view through the actuating device100in the II-II plane ofFIG.3in the region of coupling apparatus10. In order to be able to effect a blocking and then be able to unblock it again, the first coupling element11of the coupling apparatus10has a first section16with outer longitudinal toothing which extends in the longitudinal direction of the first coupling element11as well as a second section18without teeth which likewise extends in the longitudinal direction of the first coupling element11and directly adjoins the first section16. Further provided is a third section19adjoining the second section18which likewise extends in the longitudinal direction of the first coupling element11and likewise exhibits an outer longitudinal toothing. Longitudinal toothing here means the provision of structures running substantially parallel to the longitudinal direction A of the coupling apparatus10, for example grooves, prismatic projections or the like.

The sleeve-shaped locking element13B has an inner longitudinal toothing17of corresponding design to the geometry of the first section16and third section19toothing over part of its axial length (in particular parallel to the longitudinal axis A of the coupling apparatus10). The inner longitudinal toothing17only extends axially over an area of length corresponding at most to the width of the second section18without teeth so that the locking element13B is rotatable about the first axis (corresponding substantially to the longitudinal axis A of the coupling apparatus10) when the first coupling element11with the outer longitudinal toothing is axially displaced relative to the locking element13B such that the inner longitudinal toothing17of the locking element13B is not in engagement with the outer longitudinal toothing of the first coupling element11but rather is at the height of the second non-toothed section18; i.e., between sections16and19.

An outer diameter of the second non-toothed section18of the first coupling element11is thereby smaller in this coupling apparatus10than a tip circle diameter of the outer longitudinal toothing of the first section16of the first coupling element11, whereby in particular the outer diameter of the second section18is smaller than or equal to the root circle diameter of the outer longitudinal toothing of the first section16.

The outer longitudinal toothing of the third section19serves to improve the guiding of the first coupling element11in locking element13B, wherein the toothing geometry of the outer longitudinal toothing of the third section19is of preferably identical design to the toothing geometry of the outer longitudinal toothing of the first section18.

The third section19in this exemplary embodiment is thereby arranged directly adjacent to the second non-toothed section and at the free end of the first coupling element11, wherein the individual teeth of the third section19are arranged in alignment with the teeth of the outer longitudinal toothing in the first section16.

The locking element13B is thereby in the blocking position when the coupling element11with the outer longitudinal toothing is axially displaced in the axial direction relative to the locking element13B such that the inner longitudinal toothing17is not engaged with the outer longitudinal toothing of the first section16of the first coupling element11but the inner longitudinal toothing17of the locking element13B is instead axially at the height of the non-toothed second section18and when the locking element13B is circumferentially rotated; i.e., rotated about the first axis (corresponding to longitudinal axis A) so that at least one tooth, in particular all the teeth, of the outer longitudinal toothing of the first section16of the first coupling element11are at least partially aligned axially with at least one tooth, in particular with all the teeth, of the inner longitudinal toothing17of the locking element13B, particularly such that their end faces abut one another.

A transmission of the actuating movement of the second rocker arm211to the first rocker arm210occurs when the locking element13B is in the blocking position and a relative axial displacement of the coupling element11and the locking element13B to one another is blocked. In this blocking position, the locking element13B follows the movement of the first coupling element11fixedly connected to the second rocker arm and thus transmits the actuating movement of the second rocker arm211to the second coupling element12.

Accordingly, the locking element13B is in the unblocking position when the locking element13B is rotated in the circumferential direction so that all the teeth of the outer longitudinal toothing of the first section16of the first coupling element11are arranged offset relative to all the teeth of the inner longitudinal toothing17of the locking element13B such that the teeth of the outer longitudinal toothing of the first coupling element11engage with the teeth of the inner longitudinal toothing17at least over part of their axial length. A movement of the second rocker arm211is conversely dissipated or respectively ineffective when the locking element13B is in the unblocking position so that the first coupling element11can dip into the cylinder-like section of the locking element13B unhindered without any movement of the first coupling element11being transmitted to the second coupling element12.

The locking element13B is preferably axially braced against the second coupling element12by means of a spring element49when the locking element13B is in the unblocking position. For improved second coupling element12guidance, the cylinder base of the locking element13B is preferably curved inwardly and a free end of the second coupling element12is correspondingly convexly curved.

Doing so enables a defined valve lift to be selectively enabled or disabled by a mechanical switching device.

FIG.5shows an enlargement of the perspective representation ofFIG.1, wherein shown in particular is an embodiment of the switching device110of the valve-actuating device100.

The switching device110comprises a slotted guide element84and a triggering element111, wherein the slotted guide element84is configured to actuate the coupling apparatus10. In order to cause the locking element13B to rotate about the longitudinal axis A of the coupling apparatus10to that end, the tappet13A can be displaced by means of the slotted guide element84. The slotted guide element84can thereby be displaced substantially parallel to the shaft216(not shown inFIG.5) and/or the rotational axis213. To improve the interaction of the slotted guide element84and the locking element13B, the slotted guide element84preferably has a jaw85on its end facing tappet13A which is designed to interact with tappet13A of the locking element13B and is preferably designed in U-profile.

The slotted guide element84is preferably84movably mounted on a guide rod83and an actuating rod81, the triggering element111mounted at least on the actuating rod81. The longitudinal axes of the guide rod83and the actuating rod81run parallel to each other, preferably also parallel to the rotational axis213and to the shaft216but perpendicular to the actuating movement and to the longitudinal axis A of the coupling apparatus10. The actuating rod81is configured to move the slotted guide element84on the guide rod83.

To that end, the slotted guide element84and the triggering element111are clamped between two stops89,89′ arranged on the actuating rod81(one stop is obscured inFIG.5) by means of two spring elements93,94. The stops89,89′ are thereby preferably designed as annular disks fixed to the actuating rod81in order to block an axial displacement of the spring elements93,94along the longitudinal axis of the actuating rod81to enable a preloading of the spring elements93,94with respect to the slotted guide element84.

The switching device110comprises a blocking element112which is designed to interact with the triggering element111so as to block or enable axial displacement of the slotted guide element84. The blocking element112in the depicted embodiment is configured in the form of a locking disk. Reference numeral112is therefore used for the locking element and for the locking disk in the following, respectively in general. The locking disk112is mounted on the shaft216axially offset to the first and second cam214,215and can thus be rotated in sync with the two cams214,215.

The triggering element111of the depicted embodiment has a release pin115in radially projecting arrangement from the actuating rod81and capable of interacting with the locking disk112. The release pin115or the entire triggering element is preferably pivotably mounted about the actuating rod81and further preferably held in a defined arrangement in relation to the slotted guide element84by a return spring114. A defined arrangement is to be understood here particularly as the direction in which the release pin115protrudes radially from the actuating rod81.

In a first position, the release pin115is arranged on a first side of the locking disk112opposite from the coupling apparatus10. Preferably, the release pin115is configured so as to be able to rolled along the locking disk112rotating with the shaft216when needed.

When the actuating rod81is axially displaced toward the coupling element10to switch the switching device10, the release pin115locks on the locking disk112. This thus also blocks displacement of the triggering element111and slotted guide element84along the actuating rod81or guide rod83respectively. A first spring element93, which is arranged on the side of the slotted guide element84opposite from the coupling element10, is thereby preloaded.

The locking disk112has a switching window113in the form of a void on its outer circumference. The switching window113is designed such that the triggering element111, in particular the release pin115, can pass through the switching window113when the switching window113situates in the region of the release pin115upon the locking disk112rotating about shaft216. The longitudinal extension of the switching window113along the circumference of the locking disk112thus defines a window of time in which actuation of the coupling apparatus10by the switching device110is possible.

The triggering element111, in particular the release pin115, passing through the switching window113in consequence of the preloading of the spring element93enables a displacement of the triggering element111and the slotted guide element84. The triggering element111and the slotted guide element84are then axially displaced along the actuating rod83, here in the direction of the coupling apparatus10. The axial displacement of the slotted guide element84effects a rotational movement of the locking element13B, in particular via tappet13A, and thus shifts the locking element13B from a blocking position into an unblocking position or vice versa.

In a second position, the release pin115is arranged on a second side of the locking disk112facing the coupling apparatus10. When the actuating rod81axially displaces away from the coupling element10, the release pin115locks on the locking disk112inasmuch as it encounters the locking disk112outside of the switching window113. An axial displacement of the triggering element111and the slotted guide element84along the actuating rod81or guide rod83respectively is thus blocked. A second spring element94arranged on the side of the slotted guide element84facing the coupling element84is thereby preloaded.

The triggering element111, in particular the release pin115, passing through the switching window113in consequence of the preloading of the spring element93enables a displacement of the triggering element111and the slotted guide element84. The triggering element111and the slotted guide element84are then axially displaced on the actuating rod83, here in the direction away from the coupling apparatus10. The axial displacement of the slotted guide element84effects a rotational movement of the locking element13B, in particular via tappet13A, and thus switches the locking element13B from a blocking position into an unblocking position or vice versa.

FIGS.6to8show a further plan view of the exemplary embodiment of the valve-actuating device along rotational axis213or shaft216respectively, which in each case runs normal to the plane of the page, whereby the plan view is this time from the side opposite from the slotted guide element84. The release pin115is thereby either in the first position (FIG.6, obscured by the locking disk112) or in the second position (FIGS.7and8). These figures will be referenced in describing a switching process by the switching device110.

InFIG.6, the release pin115is in the first position. Since the actuating rod81determines a switching of the switching device110, a force is exerted via the spring elements (not shown) on the triggering element111, and thus release pin115, in order to get to the second position. Since the locking disk112blocks a displacement of the triggering tappet, and thus release element111and slotted guide element84, the release pin115abuts against the locking disk112, whereby a roller attached to the release pin115rolls along a non-visible side of the locking disk112rotating together with the first cam214.

When the release pin reaches the void or respectively switching window113of the locking disk112, the release pin115passes through the void113and reaches the second position. The triggering element111and the slotted guide element84, which is coupled to the triggering element111, are displaced on the guide rod83and the actuating rod81with the release pin115. This state is depicted inFIG.7.

InFIG.8, cam214and locking disk112have rotated further so that the release pin has reached the end of the switching window113void. The release pin115should be in the second position at this point and then begins to roll along on the visible side of the locking disk112. The triggering element111and the slotted guide element84are then blocked and both can be pretensioned again by the actuating rod81, this time in the opposite direction.

However, at the end of the switching window113void, there is a risk of the flank of the locking disk112subjecting the release pin to a load in the rotational direction of the locking disk112when it is in an intermediate position between the first and second position, and it breaking off as a result.

This is prevented by the pivotable mounting of the release pin115or the entire triggering element111, particularly against the force of the protective spring114. Preferably, as shown in the figures, the triggering element111is to that end pivotably mounted on the actuating rod81. The protective spring114always returns the release pin115back to its original position.

As shown in even further enlarged depiction inFIG.9andFIG.10, the release pin115can pivot away should it encounter the flank of the void, or respectively switching window113, due to a misalignment. When the triggering element111finally reaches the second position, it is pivoted back again by a force provided by the return or protective spring114(not shown inFIG.9andFIG.10).

FIG.11shows an exemplary embodiment of two different valve lift curves able to be realized with the valve-actuating device100according toFIGS.1and2. A valve opening is thereby given as a function of the crankshaft angle.

The IVC-480 valve lift curve is from a Miller cycle and is produced by the first cam214, thus a so-called Miller cam, in the exemplary embodiments of the valve-actuating device100shown in the previous figures.

While operation of a combustion engine in Miller operation is particularly optimized in terms of consumption, it cannot be started in Miller operation because the cylinder fill is too low.

The IVC-580 valve lift curve belongs to a different combustion cycle in which the valves are both open for longer as well as have a larger valve lift of 8.7 mm more than the Miller cycle shown. This IVC-580 valve lift curve is produced by the second cam215. The IVC-580 valve lift curve therefore overlaps the IVC-480 valve lift curve.

As indicated inFIG.11, the rise in the IVC-580 valve lift curve is chronologically subsequent to the rise in the IVC-480 valve lift curve. This thereby ensures that a large part of the forces occurring in the valve-actuating device100when the valves are opened is transmitted via the more stable rigid first rocker arm210(force flow F1). Only about a third of the forces then act on the variable or adjustable rocker arm211. It can therefore be of less strong design and of smaller dimensions, in particular narrower.

Accordingly, a flank of the second cam215rises later than the flank of the first cam214with respect to an operational direction of rotation of the shaft216. As a result, an actuating movement of the first rocker arm210is effected at a different, preferably earlier, point in time than an actuating movement of the second rocker arm211. The combustion engine, in particular a so-called large engine, is preferably operated in the Miller cycle for more than 90% of the operating period. The IVC-580 valve lift curve is preferably only used when starting and when in transient sail mode (also called coasting mode).

It should be noted that the exemplary embodiments described above are only examples which are in no way intended to limit the scope of protection, application and configuration. Rather, the foregoing description is to provide the person skilled in the art with a guideline for implementing at least one exemplary embodiment, whereby various modifications can be made, particularly as regards the function and arrangement of the described components, without departing from the scope of protection resulting from the claims and from equivalent combinations of features. In particular, the valve-actuating device can also be a cam follower or a rocker or similar device. The switching device can moreover be of different configuration, in particular according to the variants shown in document WO 2019/025511 A1.

LIST OF REFERENCE NUMERALS

10coupling apparatus11first coupling element12second coupling element13A tappet13B locking element16first section of first coupling element1117inner longitudinal toothing of sleeve-shaped locking element13B18second section of first coupling element1119third section of first coupling element1181actuating rod83guide rod84slotted guide element85link, jaw, U-profile89stop93,94spring element100valve-actuating device110switching device111triggering element112blocking element (locking disk)113switching window114protective spring115release pin210first rocker arm or finger follower211second rocker arm or finger follower213rotational axis214first cam215second cam216shaft217coupling section218first pick-up219second pick-up220pushrod221lock nutA longitudinal axis of coupling apparatus10F1first force transmission pathF2second force transmission path