AT521446B1 - VALVE GEAR DEVICE FOR AN INTERNAL ENGINE - Google Patents

Abstract

The invention relates to a valve drive device (100, 200) for an internal combustion engine, having at least one cam element (102, 202) that can be displaced on a camshaft (101, 201) and an adjusting device (105, 205) associated therewith for displacing the cam element (102, 202). , wherein the cam element (102, 202) has at least two different cams (103, 104; 203, 204) and between at least two switching positions (A, B) parallel to the axis of rotation (101a, 201a) of the camshaft (101, 201) in one first (A2) and a second direction of displacement (B2), and wherein the adjusting device (105, 205) has a link guide (106, 206) with at least two sliding elements (107a, 107b; 207a, 207b) that fit together in a form-fitting manner, one of which first sliding element (107a, 207a) at least one slideway (108a, 108b; 208a, 208b) and a second sliding element (107b, 207b) at least one sliding block (109a, 109b; 209a, 209b), one of the mating sliding elements (107a, 107b; 207a, 207b) being associated with a first (111a, 211a) and a second shifting claw element (111b, 211b) and the shifting claw elements (111a, 111b; 211a, 211b) are rotatably connected to a pivot shaft (112, 212) and the other mating slide member (107b, 107a; 207b, 207a) is fixedly connected to the cam member (102, 202). A simple switching can be achieved if the actuation of at least one shifting claw element (111a, 111b; 211a, 211b) by rotating the pivot shaft (112, 212) between at least a first rotational position (A1) of a shifting claw element (111a, 111b; 211a, 211b) and a second rotational position (B1) of the shifting claw element (111a, 111b; 211a, 211b), wherein at least one shifting claw element (111a, 111b; 211a, 211b) can be actuated elastically.

Description

description

The invention relates to a valve drive device for an internal combustion engine with at least one cam element that can be displaced on a camshaft and an adjusting device assigned to the cam element for displacing the cam element, the cam element having at least two different cams and being displaceable between at least two switching positions parallel to the axis of rotation of the camshaft and wherein the adjusting device has a link guide with at least two sliding elements that fit together in a form-fitting manner, of which a first sliding element has at least one - preferably slot-shaped or groove-shaped - sliding track and a second sliding element has at least one sliding block that can be guided by means of the sliding track, with one of the matching sliding elements having a first shifting claw element and a second shift dog member is associated and the shift dog members are rotatably connected to a pivot shaft, and the other mating slide telement is firmly connected to the cam element, wherein at least one shifting claw element - preferably both shifting claw elements - is actuated by rotating the pivot shaft between at least a first rotary position of a shifting claw element and at least a second rotary position of the shifting claw element, and wherein the pivoting shaft is rotated by at least one on the Pivot shaft acting actuator takes place.

Variable valve train devices are known in internal combustion engines, which by axially shifting cam pieces with cams of different cam contours (e.g. full cams, half cams and/or zero cams) can implement both the deactivation of individual cylinders and a valve lift changeover (so-called “shift cam systems”). Such valve train devices with axially displaceable cam pieces do not have a classic one-piece camshaft, but rather a cam base shaft on which two or more cam pieces are displaceably arranged.

The document JP 2011-122498 A discloses a variable valve train with a camshaft and a rotatable pivot shaft which is pivoted by a rotating device arranged on the camshaft. Connected to the pivot shaft are two shifting claws which are connected to one another in the form of a fork and which can alternatively engage in a sliding track arrangement of the camshaft. This allows the camshaft to be moved axially. The shifting claws can be actuated with sliding blocks engaging in the grooves of the slideway arrangement, the sliding blocks being elastically connected to the shifting claws via a flat spring.

DE 10 2007 048 915 A1 describes a valve train device of an internal combustion engine with at least one cam element that can be displaced axially via an adjustment device, the cam element being fixable by means of a fixing device. Adjusting device and fixing device are made in one piece. The adjusting device is actuated via a hydraulic actuating device, and is reset mechanically via a spring force. JP 2010 249123 A shows a similar arrangement.

[0005] DE 10 2014 019 573 A1 discloses a valve train device for an internal combustion engine, which has an axially displaceable cam element and an adjustment device designed as a link guide with a first and a second engagement element. The engagement elements designed as shifting claws with sliding blocks are designed to move the cam element into a first or second shifting position. The adjusting device also has a first slideway, in which the first engagement element is guided in the first switching position, and a second slideway, in which the second engagement element is guided in the second switching position. The first and the second engagement element are designed to be positively coupled. The adjusting device also has an electrical triggering device in order to hold the first engagement element in the second switching position against a restoring force.

There is usually only one rotational position per link track and engagement element, in which the engagement element engages in the link track. So switching must be precise

be carried out in this rotational position in order to avoid damage or premature wear of the link guide. However, a relatively high level of control effort is required for switching with an exact angle of rotation--particularly in the case of internal combustion engines with a plurality of cylinders.

The object of the invention is to provide a low-wear valve drive device with which the control effort for switching between the switching positions can be reduced.

Based on a valve drive device of the type mentioned, this object is achieved according to the invention in that an elastic transmission element is arranged between the actuating element and at least one shifting claw element, so that at least one shifting claw element—preferably both shifting claw elements—can be actuated elastically.

"Elastically operable" means here that an indirect and time-delayed switching process is possible - a certain period of time can therefore optionally elapse between the time of the switching command and the activation of the link guide. For this purpose, the actuation takes place via the U transmission element, which can absorb energy, store it and (with a time delay) release it again. As a result, the switching point in time of the pivot shaft can be selected independently of the rotary position of the camshaft. If the pivot shaft is shifted at a point in time that is unfavorable for the displacement of the cam element - i.e. when the sliding block of the second sliding element cannot yet engage in the corresponding sliding track - the sliding block lies outside of the sliding track on a lateral surface of the first sliding element, with the shifting claw element being U transmission member is elastically biased. The further rotation of the camshaft finally reaches a rotational position in which the sliding block and slideway overlap radially, whereby the sliding block engages in the slideway through the prestressed shifting claw element and the cam element is displaced accordingly by the link guide.

The pivot shaft is rotated by the at least one actuating element acting on the pivot shaft. As a result, the pivot shaft is advantageously rotated between at least the first rotational position and the second rotational position. Switching back from the second rotary position to the first rotary position is preferably also effected by this actuating element. However, it is also possible to use a separate actuating element for downshifting. The actuation and/or the operating principle of the actuating element can be of a hydraulic and/or pneumatic and/or mechanical and/or electrical type.

In a further embodiment of the invention it is provided that at least one slide - preferably at least one end of the track - has a reset ramp. In the area of the return ramp, the bottom of the slideway is rising, ie the radial distance of the bottom of the slideway from the axis of the camshaft increases towards the end of the track end and tapers off flat towards the surface of the camshaft. The reset ramp--preferably supported by actuation of the pivot shaft--resets the shifting claw element after the shifting process has ended to a neutral position that defines an initial position, in which neither of the two sliding blocks of the shifting claws engages in one of the slideways. Each of the two slideways preferably has such a return ramp at the respective end of the track. In this variant, the two slideways are completely separate. In this embodiment variant, the shifting claw elements thus have three rotational positions: a first rotational position, a neutral position and a second rotational position.

In one embodiment of the invention it is provided that an elastic transmission member is arranged between the actuating element and at least one shifting claw element, the pivot shaft preferably being rotationally connected to the shifting claw element via the elastic transmission member. The elastic transmission element is able to absorb the angular momentum of the pivot shaft, store it as potential energy and release it again to the shifting claw element.

[0013] The term "torsionally connected" is understood here to mean any torsionally rigid or torsionally flexible connection which transmits a rotary momentum from the pivot shaft to the shifting claw element.

ments made possible. The shifting claw elements can thus be indirectly rotationally connected to the pivot shaft, with the elastic U-transmission member being arranged between the pivoting shaft and the shifting claw elements. The shifting claw elements are rotatably mounted around the pivot shaft, the rotational drive of the shifting claw elements by the pivoting shaft takes place only via the elastic transmission member, which thus produces a torsionally flexible connection between the pivoting shaft and shifting claw elements.

As an alternative to this, the shifting claw elements can be connected in a rotationally fixed manner to the pivot shaft. The shifting claw elements are twisted directly and immediately by the pivot shaft. In this case, the elastic transmission member is arranged between the operating element and the pivot shaft.

According to an embodiment of the invention, the elastic transmission member is designed as a torsion spring or torsion bar spring. In particular, for example, the pivot shaft itself can be formed by a torsion bar spring.

Alternatively or additionally, the actuating element or at least a part thereof itself can be elastic. For example, an elasticity can be provided for this purpose in the actuator system of the actuating element.

Preferably, the first rotational position of the pivot shaft is associated with the first axial switching position of the cam element and the second rotational position of the pivot shaft is associated with the second axial switching position of the cam element. In order to switch between the first and second switch position, the pivot shaft is rotated by a defined angle of rotation from the first to the second rotary position. Switching from the second to the first switching position takes place in the opposite direction by rotating the pivot shaft from the second rotary position to the first rotary position.

[0018] By using the link guide, only small forces are required for the adjustment of the valve train device. The shifting forces for the first valve lever are provided by the drive of the camshaft. Only relatively small actuating forces are required to actuate the shifting claw elements by rotating the pivot shaft.

A link guide (slot/pin control) is understood here to mean a mechanical transmission element for mechanical power transmission, with the aid of which positive control of a pin-like sliding block (second sliding element) in a sliding guide (first sliding element) having at least one slideway is possible. The slideway can be formed, for example, by a helical groove in the jacket of a shaft or axle or shaft sleeve or the inside of such a shaft sleeve. By rotating the shaft or axle or shaft sleeve, the sliding element connected to this and the cam element connected to this sliding element are displaced axially. A sliding guide of this type for forced guidance of sliding elements is known, for example, from DE 10 2016 210 976 A1.

An embodiment variant of the invention provides that the first sliding element has a helical first slideway and a helical second slideway, with the two slideways having differently oriented slopes, with the first slideway and the second slideway preferably - in relation to the displacement directions of the Cam element - are arranged offset to one another axially (ie in the direction of the camshaft axis). Due to the differently oriented gradients of the slideways, the cam element can be moved in opposite directions by the camshaft rotating in the same direction.

In one variant of the invention, at least one slideway opens into an annular slideway section or ring-segment-shaped slideway section, which is designed without a gradient. The first and the second slideway preferably open out obliquely into the ring-shaped or ring-segment-shaped slideway section at different end faces. The ring-shaped third slideway arranged between the two outer slideways serves to position and hold the cam element in place as soon as the targeted switching position has been reached.

In one embodiment of the invention it is provided that the first shift claw element and the second shift claw element are formed by a shift fork.

Each switching movement therefore has its own - first or second - sliding track and its own - first or second - sliding block: for switching from the second to the first switching position, the first sliding track and the first sliding block are activated, for the Switching from the first switching position to the second switching position activates the second sliding track and the second sliding block.

In order to save parts, an embodiment variant of the invention provides that the first and the second shifting claw element are formed by a one-piece shifting fork. As an alternative to this, the first and the second shifting claw element of the shifting fork can also be designed as separate parts. This enables an embodiment variant in which at least one elastic transmission element can be arranged in the axial direction along the pivot shaft between two bearing bushes of the first shifting claw element and the second shifting claw element on the pivot shaft, resulting in a compact and space-saving design. The two bearing bushes of the shifting claw elements or shifting fork are thus arranged offset in the axial direction along the pivoting shaft on the pivoting shaft, with the elastic transmission element located in between. Components can be saved if the shift fork is rotatably connected to the pivot shaft via a single elastic U-transmission member.

The shape and arrangement of the slideways of the slotted guides ensures that switching between the two cams of the cam element can only take place in the area of their base circles.

In one variant of the invention, two sliding blocks are provided, with a first sliding block and a second sliding block being offset from one another in at least one displacement direction of the cam element. The directions of displacement preferably run parallel to the axis of the camshaft.

According to one embodiment of the invention it is provided that at least one slideway is firmly connected to the cam element and that at least one sliding block corresponding to this slideway is arranged on a shifting claw element.

A further embodiment variant of the invention provides that at least one slideway is arranged on a shifting claw element and that at least one sliding block corresponding to this slideway is firmly connected to the cam element.

The invention is explained in more detail below with reference to non-limiting exemplary embodiments that are shown in the figures.

Therein show:

1 shows a valve train device according to the invention in a first embodiment variant in an axonometric view,

[0032] FIG. 2 this valve drive device in a side view,

[0033] FIG. 3 shows the valve train device in a first switching position,

[0034] FIG. 4 shows the valve drive device in a second switching position,

[0035] FIG. 5 shows a shift fork of the valve drive device in an axonometric representation, [0036] FIG. 6 shows this shift fork in a further axonometric representation,

7 shows a valve train device according to the invention in a second embodiment variant in a front view,

[0038] FIG. 8 this valve train device in a side view, [0039] FIG. 9 a part of the valve train device in an axonometric representation, [0040] FIG. 10 a detail of the valve train device in an axonometric representation,

[0041] FIG. 11 shows a shift fork of the valve drive device in an axonometric view and

[0042] FIG. 12 shows a valve drive device according to the invention in a third embodiment variant in an axonometric representation.

1 to 6 show a valve drive device 100 for actuating at least one gas exchange valve of an internal combustion engine (not shown in more detail) in a first embodiment variant, and FIGS. 7 to 11 show a valve drive 200 for actuating at least one gas exchange valve 219 of an internal combustion engine, for example via a valve lever 220, in a second variant.

Valve drive devices 100, 200 are used to switch between two differently shaped cams 103, 104; 203, 204 to realize different valve lifts.

In each of the two illustrated embodiment variants, the valve train device 100, 200 has a camshaft 101, 201 with at least one cam element 102, 202 that can be displaced axially between two switching positions A, B, on which a first cam 103, 203 and a second cam 104 , 204 are arranged. The first cam 102, 202 and the second cam 103, 203 are non-rotatably connected to the camshaft 101, 201 via the cam element 102, 202 and are arranged directly next to one another. The first cams 103, 104 and second cams 203, 204 have base circular surfaces 103a, 104a; 203a, 204a with the same base circle radius r, but different cam elevations 103b, 104b; 203b, 204b. The base circular areas 103a, 104a; 203a, 204a of the two cams 103, 104; 203, 204 are designed to run axially into one another.

The cam element 102, 202 is adjusted via an adjusting device 105, 205 associated with the cam element 102, 202, with a link guide 106, 206, which has two sliding elements 107a, 107b; 207, 207b, of which a first sliding element 107a, 207a has at least one slideway 108a, 108b; 208a, 208b and a second sliding element 107b, 207b at least one by means of the slideway 108a, 108b; 208a, 208b guided sliding block 109a, 109b; 209a, 209b. The slotted guide 106, 206 for displacing the cam element 102, 202 has its own slideway 108a, 108b; 208a, 208b and a separate sliding block 109a, 109b; 209a, 209b - i.e. a slot-shaped or groove-shaped first slideway 108a, 208a and a pin-shaped first slide block 109a, 209a for the adjustment to a first switching position A, and a slot-shaped or groove-shaped second slideway 108b, 208b and a pin-shaped second slide block 109b, 209b for the adjustment into a second switching position B of the cam element 102, 202, the sliding blocks 109a, 109b; 209a, 209b and the slideways 108a, 108b; 208a, 208b are dimensioned to fit in a form-fitting manner. This means that the diameter of each sliding block 109a, 109b; 209a, 209b is slightly smaller than the width of the corresponding slideway 108a, 108b; 208a, 208b. The immersion length of the sliding block 109a, 109b; 209a, 209b must of course match the depth of the corresponding slideway 108a, 108b; 208a, 208b.

The first slideway 108a; 208a, and the second slideway 108b; 208b are designed helically with differently oriented pitches in order to allow differently oriented switching movements of the cam element 102, 202 while the rotational movement of the camshaft 101, 201 remains the same. First 108a; 208a and second slideway 108b; 208b are - in relation to the displacement direction of the cam element 102, 202 - arranged axially offset from each other.

In each of the two variants, one of the matching sliding elements 107a, 107b; 207a, 207b has a shift fork 110, 210 with a first shift claw element 111a, 211a and a second shift claw element 111b, 211b, the shift fork 110, 210 being connected in the region of a first end 110a, 210a with a pivot shaft 112 arranged parallel to the camshaft 101, 201, 212 is rotationally connected. The shift fork 110, 210 is axially fixed but pivotable between a first A1 and a second rotational position B1 about the axis

112a, 212a of the pivot shaft 112, 212.

The pivot shaft 112, 212 can simultaneously form the pivot axis for at least one rocker arm according to an embodiment not shown, to the valve lift of the cams 103, 104; 203, 204 to be transferred to gas exchange valves. The other mating sliding element 107b, 107a; 207b, 207a is firmly connected to the cam element 102, 202. The pivot shaft 112, 212 can be rotated between a first rotational position A1 and a second rotational position B1 by means of a hydraulic, pneumatic, mechanical or electrical actuating element 113, 213. The first rotary position A1 of the pivot shaft 112, 212 is assigned to the first switch position A of the cam element 102, 202 and the second rotary position B1 of the pivot shaft 112, 212 to the second switch position B of the cam element 102, 202.

The shifting claw elements 111a, 111b; 211a, 211b are not rigidly but elastically connected to the selector shaft 112, 212. For this purpose, an elastic U transmission member 114, 214 is arranged in the drive path between the pivot shaft 112, 212 and the shift fork 110, 210, which is formed by a torsion spring 115, 215 in the exemplary embodiments. It is also conceivable to design the pivot shaft 112, 212 itself as a torsion bar spring, or to design the actuating element 113, 213 or parts thereof to be elastic. For this purpose, for example, an actuator system in the actuating element 113, 213, which actuates the pivot shaft 112, 212, can be designed with elasticity, e.g. a leaf spring, a torsion element or the like. Between actuating element 113, 213 and shifting claw elements 111a, 111b; 211a, 211b, additional elasticity would then no longer be necessary, but it can also be provided.

When the pivot shaft 112, 212 is rotated by the actuating element 113, 213, the first driver pin 117a, 217a protruding radially from the pivot shaft 112, 212 simultaneously rotates the shift fork 110, 210 with the first 111a, 211a and second shift claw elements 111b, 211b the torsion spring 115, 215 and the second driver pin 117b, 217b of the shift fork 110, 210. Should the case arise that, due to the position of the link guide 106, 206, the controlled first 109a, 209a or second sliding block 109b, 209b slides into the corresponding first 108a, 208a or second slideway 108b, 208b cannot be inserted. The first 109a, 209a or second sliding block 109b, 209b in question is in contact with the outer lateral surface of the first sliding element 107a, 207a and cannot yet enter the corresponding slideway 108a, 108b; 208a, 208b engage - the torsion spring 115, 215 is pretensioned. As soon as the mentioned first 109a, 209a or second sliding block 109b, 209b and the corresponding first 108a, 208a or second slideway 108b, 208b overlap radially, the preloaded torsion spring 115, 215 presses the sliding block 109a, 209a, 109b, 209b into the slideway 108a , 208a, 108b, 208b, whereby the axial displacement of the cam element 102, 202 begins. The axial displacement ends as soon as the sliding block 109a, 209a, 109b, 209b the ring-shaped or ring-segment-shaped slide ring portion 108c; 208c, 208d reached. The arrangement of the torsion spring 115, 215 between the two bearing sleeves 116a, 116b; 216a, 216b of the shift fork 110, 210 enables actuation in both directions of rotation with a single elastic transmission element 114, 214 in both variants.

In the illustrated exemplary embodiments, in the region of the first end 110a of the shift fork 110 and the shifting claw elements 111a, 111b; 211a, 211b, a first bearing bush 116a, 216a and a second bearing bush 116b, 216b are provided, via which the shifting claw elements 111a, 111b; 211a, 211b are rotatably supported around the pivot shafts 112, 212. The two bearing bushes 116a, 216a; 116b, 216b are arranged on the pivot shaft 112, 212 at a defined axial distance a from one another. Between the two bearing bushes 116a, 216a; 116b, 216b, the torsion spring 115, 215 is arranged around the pivot shaft 112, 212. The torsion spring 115, 215 has at its ends a first leg 115a, 215a and a second leg 115b, 215b, helical windings being formed around the pivot shaft 112, 212 between the first leg 115a, 215a and the second leg 115b, 215b. The first leg 115a, 215a and the second leg 115b, 215b are bent in a direction parallel to the axis 112a, 212a of the pivot shaft 112,212.

In the area of the distance a between the two bearing bushes 116a, 216a; 116b, 216b, the pivot shaft 112, 212 has a radially protruding first driver pin 117a, 217a on the circumference. Furthermore, at least one bearing bush 116a, 216a; 116b, 216b on the circumference a radially protruding second driver pin 117b, 117c; 217b, 217c. The torsion spring 115, 215 is installed in such a way that the first leg 115a, 215a and the second leg 115b, 215b are attached to the first 117a, 217a and second driving pin 117b, 117c; 217b, 217c rest on both sides with a defined pretension.

The time of the rotational changeover of the shift fork 110, 210 is independent of the angular position of the camshaft 101, 201, since the slideways 108a, 108b; 208a, 208b and the sliding blocks 109a, 109b; 209a, 209b are positioned in such a way that the adjustment process only takes place on the base circular surface 103a, 104a; 203a, 204a of the first cam 103, 203 and second cam 104, 204 takes place.

The shift fork 110, 210 remains in the two - forming end positions - rotary positions A1, B1 until the hydraulic, pneumatic, mechanical or electrical actuator 113, 213 switches to the other rotary position B1, A1 takes place.

The illustrated embodiment thus relates to a variant where essentially two positions are provided. Alternatively, in addition to the first rotary position and the second rotary position, a neutral position can also be provided for the shift fork 110, 210, in which neither of the two sliding blocks 109a, 109b; 209a, 209b into a slideway 108a, 108b; 208a, 208b engages. In addition to the first and second rotary position, there is a neutral position in which no rotary process is initiated.

The pivot shaft 112, 212 is basically in a starting or standard position in the neutral position. It can be turned from the neutral position into a first rotational position by turning it in a first direction of rotation, as a result of which the cam element 102 is adjusted. When the adjustment is made, the pivot shaft 112, 212 can be rotated back to the neutral position. If required, the pivot shaft 112, 212 can be brought from the neutral position into the second rotational position by rotating it in a second rotational direction.

The neutral position is thus defined by a passive central position of the actuating element 113, 213, in which none of the sliding blocks 109a, 109b; 209a, 209b is in the engaged position. 2 shows the shift fork 110 in such a neutral position, for example.

In particular, it is also possible in this embodiment variant with three rotary positions to dispense with the ring-shaped or ring-segment-shaped slide ring section 108c and to provide only the slideways 108a, 108b with differently oriented slopes. This variant is shown in FIG.

For this purpose, use is made of the fact that the slideways 108a, 108b each have reset ramps 118 at their ends, as shown in FIG. 12, for example. In the area of the reset ramp 118, the bottom of the slideways 108a, 108b is designed to rise (or fall) in each case. The radial distance of the bottom of each track 108a, 1086 from the axis 101a of the camshaft 101 increases towards the end of the track and tapers to the outer surface 120 of the camshaft 101 via an edge 119 flat. In other words, the slideways 108a, 108b respectively start and end at the outer surface 120 of the cam element 102 with the edge 119 and increase in depth circumferentially to a maximum where they are at the smallest radial distance from the axes 101a before the depth decreases again and the slideway 108a, 108b merges flat into the outer surface 120 of the cam element 102 at an edge 119.

Due to the reset ramps 118, the shifting claw element 111a, 111b or its sliding block 109a, 109b is located on an outer surface 120 of the cam element 102 after the end of the shifting process; if the pivot shaft 112 is returned to a neutral position, a starting position for the next shifting operation is defined. In this variant, the two slideways 108a, 108b are designed to be completely separate from one another.

In other words, in this exemplary embodiment, the cam element 102 has a first slideway 108a and a second slideway 108b with differently oriented slopes. The slideways 108a, 108b have a reset ramp 118 in their beginning and end regions (that is to say where they start from or open into the outer surface 120 of the cam element 102). Preferably, the reset ramp 118 transitions into the outer surface 120 of the cam member 102 via an edge 119 .

The shifting claw elements 111a, 111b and/or the rotary shaft 112 have, in addition to the first A1 and second rotary position B1, a neutral position in which the sliding elements 107a, 107b are not in engagement with one another.

For all of the described embodiments, there is a major advantage in that the pivot shaft 112, 212 enables several shift forks 110, 210 and thereby several axially displaceable cam elements 102, 202 arranged on a camshaft 101, 201, each with several cams 103, 104; 203, 204 can be actuated with only one actuating element 113, 213 acting on the pivot shaft 112, 212. In order to enable several shift forks 110, 210 to be shifted with one pivot shaft 112, 212, the rotary connection between pivot shaft 112, 212 and shift fork 110, 210 is ensured by means of the elastic transmission member 114, 214 in each case. This allows the sliding blocks 109a, 109b; 209a, 209b engage in the slideways 108, 208 at the next possible point in time after the switching command and the rotational adjustment of the pivot shaft 112, 212.

In both exemplary embodiments, the two switching positions of the cam element 102, 202 are labeled A, B and the two rotational positions of the shift fork 110, 210 or the shifting claw elements 111a, 111b; 211a, 211b labeled A1, B1. The displacement directions of the cam element 102, 202 are denoted by A2, B2, with the cam element 102, 202 in the first displacement direction A2 from the second switching position B to the first switching position A and in the second displacement direction B2 from the first switching position A to the second switching position B is moved.

In the first exemplary embodiment illustrated in FIGS. 1 to 6, the first sliding element 107a, which has the slot-shaped or groove-shaped first and second slideways 108a, 108b, is firmly connected to the cam element 102 or formed by the cam element 102. The second sliding element 107b with the first sliding block 109a and the second sliding block 109b is designed as a shift fork 110 and has a first shifting claw element 111a and a second shifting claw element 111b, which shifting claws 111a, 111b surround the camshaft 101. In the region of a first end 110a, the shift fork 110 is rotationally connected to the pivot shaft 112 arranged parallel to the camshaft 101 .

At the first end 110a facing away from the second end 110b of the first shift claw element 111a, the first sliding block 109a is arranged, which fits together with the first slideway 108a and can engage in it. Analogous to this, the second sliding block 109b is arranged at the second end 110c of the second shifting claw element 111b, facing away from the first end 110a, which slide block 109b fits together with the second slideway 108b and can engage in it. The two slideways 108a, 108b have differently oriented gradients in order to enable displacement of the cam element 102 parallel to the axis of rotation 101a of the camshaft 101 in a first displacement direction A2 and in an opposite second displacement direction B2. An annular slideway section 108c is arranged between the first 108a and the second slideway 108b, with the first 108a and the second slideway 108b coming from different end faces opening into the annular slideway section 108c. The annular slide section 108c secures the position of the cam element 102 without significant frictional losses occurring. The first slideway 108a and the second slideway 108b are used for the actual displacement of the cam element 102. There is always exactly one sliding block 109a, 109b in engagement with the slideways 108a, 108b or the slideway section 108c.

The two shifting claw elements 111a, 111b can--as in the illustrated embodiment--be formed in one piece or by separate components.

In the second exemplary embodiment illustrated in FIGS. 7 to 11, the first 209a and second sliding blocks 209b forming the first sliding element 207 are firmly connected to the cam element 202 or are formed by the cam element 202. The second sliding element 207b, which has the slot- or groove-shaped first 208a and second slideways 208b, is designed as a shift fork 210 and has the first shifting claw element 211a and the second shifting claw element 211b, which shifting claw elements 211a, 211b the camshaft 201 approximately diametrically, but - viewed in the direction of a displacement direction A2, B2 of the cam element 202 - include axially offset from one another. Each of the shifting claw members 211a, 211b is disposed on one side of a center plane & of the shift fork 210, which center plane & extends between the first 211a and second shifting claw members 211b and is formed normal to the pivot shaft 212. The shift forks 210 are rotatably mounted on the pivot shaft 212, but secured against axial displacement by securing elements 219 firmly connected to the pivot shaft 212 (FIG. 7).

The axial adjustment of the cam element 202 takes place by means of the sliding blocks 209a, 209b arranged on the cam element 202 and the shift fork 210, which in sections has first 208a and second sliding tracks 208b running obliquely, into which the sliding blocks 209a, 209b slide depending on the rotational position A1, B1 of shift fork 210 engage.

In order to keep the sliding blocks 209a, 209b and the slideways 208a, 208b friction-free in the end positions, the cam element 202 is locked by an elastic locking element 218. In the exemplary embodiment, the locking element 218 has a pressure element 218a, for example a ball, which is loaded by a spring 218b and is arranged in a radial bore 218c of the camshaft 201. Cam element 202, which is mounted on camshaft 201 in an axially displaceable but non-rotatable manner, has a first recess and a second recess (not shown) on its inner lateral surface, which are arranged such that the first recess is in the first switching position and the second Cover the recess in the second switching position with the latching element 218, the pressure element 218a being moved into the respective recess and causing the axial position of the cam element to latch in place.

The first sliding block 209a and the second sliding block 209b are formed in the manner of a pin and are arranged so as to project radially from the outer casing of the cam element 202. In this case, the first sliding block 209a and the second sliding block 209b--viewed in a displacement direction A2, B2 of the cam element 202--are arranged offset to one another. This means that normal planes on the camshaft axis 201a, which are placed through the longitudinal axes of the first sliding block 209a and the second sliding block 209b, are spaced apart from one another. Furthermore--seen in a side view of the camshaft 201--the first sliding block 209a and the second sliding block 209b can be arranged diametrically to one another on the cam element 202, as FIG. 8 shows.

In the embodiment variant shown in FIGS. 7 to 11, the first slideway 208a is arranged on the cylindrical segment-shaped inner surface of the first shifting claw element 211a, which ends in a ring-segment-shaped first slideway section 208c. Analogous to this, a second slideway 208b is arranged on the cylindrical segment-shaped inner casing of the second shifting claw element 211b, which runs out in a second slideway section 208d in the form of a ring segment. The first 208a and second slideways 208b have differently oriented gradients in order to enable displacement of the cam element 202 parallel to the axis of rotation 201a of the camshaft 201 in a first displacement direction A2 and in an opposite second displacement direction B2. The first slideway section 208c in the form of a ring segment and the second slideway section 208d in the form of a ring segment are arranged directly in the area of the center plane E of the shift fork 210 .

With the valve drive devices 100, 200 described, it is possible to issue switching commands at any time and independently of the position of the camshaft 101, 201. As a result, a particularly advantageous application in multi-cylinder internal combustion engines is possible.

[0075] Switching takes place by simply rotating the pivot shaft 112, 212 with a small

great strength. In the switching positions, no permanently applied switching force is required.

Because the two shifting claw elements 111a, 111b; 211a, 211b are positively coupled to one another mechanically by the one-piece shift fork 110, 210, the valve train device 100, 200 is largely fail-safe. The one-piece design of the shift fork 110, 210 also has the advantage that the adjusting device 105, 205 of the valve drive device 100, 200 has a high degree of rigidity. Furthermore, the one-piece shift fork 110, 210 can be made very narrow, which saves space.

Claims (16)

patent claims 1. Valve drive device (100, 200) for an internal combustion engine with at least one cam element (102, 202) that can be displaced on a camshaft (101, 201) and an adjusting device (105, 205) assigned to the cam element (102, 202) for displacing the cam element ( 102, 202), wherein the cam element (102, 202) has at least two different cams (103, 104; 203, 204) and between at least two switching positions (A, B) parallel to the axis of rotation (101a, 201a) of the camshaft (101, 201) can be displaced in a first (A2) and a second displacement direction (A2, B2), and wherein the adjustment device (105, 205) has a link guide (106, 206) with at least two sliding elements (107a, 107b; 207a, 207b) that fit together in a form-fitting manner ), of which a first sliding element (107a, 207a) has at least one - preferably slot-shaped or groove-shaped - slideway (108a, 108b; 208a, 208b) and a second sliding element (107b, 207b) has at least one slideway (108a, 108 b; 208a, 208b) guidable sliding block (109a, 109b; 209a, 209b), wherein one of the mating sliding elements (107a, 107b; 207a, 207b) is assigned a first shifting claw element (111a, 211a) and a second shifting claw element (111b, 211b). and the shift dog members (111a, 111b; 211a, 211b) are rotatably connected to a pivot shaft (112, 212) and the other mating slide member (107b, 107a; 207b, 207a) is fixedly connected to the cam member (102, 202), wherein the actuation of at least one shifting claw element (111a, 111b; 211a, 211b), preferably both shifting claw elements (111a, 111b; 211a, 211b) - by rotating the pivot shaft (112, 212) between at least a first rotational position (A1) of a shifting claw element (111a, 111b ; 211a, 211b) and at least one second rotational position (B1) of the shifting claw element (111a, 111b; 211a, 211b), and wherein the rotation of the pivot shaft (112, 212) takes place by at least one acting on the pivot shaft (112, 212). s actuating element (113, 213), characterized in that between the actuating element (113, 213) and at least one shifting claw element (111a, 111b; 211a, 211b) an elastic transmission member (114, 214) is arranged so that at least one shifting claw element (111a, 111b; 211a, 211b) - preferably both shifting claw elements (111a, 111b; 211a, 211b) - can be actuated elastically. 2. Valve drive device (100, 200) according to claim 1, characterized in that the actuating element (113, 213) is a hydraulic and/or pneumatic and/or mechanical and/or electrical actuating element (113, 213). 3. Valve train device (100, 200) according to claim 1 or 2, characterized in that the pivot shaft (112, 212) via the elastic transmission member (114, 214) is rotatably connected to the at least one shifting claw element (111a, 111b; 211a, 211b). . 4. Valve drive device (100, 200) according to one of claims 1 to 3, characterized in that the first rotational position (A1) of the pivot shaft (112, 212) corresponds to the first axial switching position (A) of the cam element (102, 202) and the second Rotational position (B1) of the pivot shaft (112, 212) is assigned to the second axial switching position (B) of the cam element (102, 202). 5. Valve drive device (100, 200) according to one of claims 1 to 4, characterized in that the first sliding element (107a, 207a) has a first slideway (108a, 208a) and a second slideway (108b, 208b), the two Slideways (108a, 108b; 208a, 208b) have differently oriented gradients. 6. Valve train device (100, 200) according to claim 5, characterized in that the first slideway (108a, 208a) and the second slideway (108b, 208b) - with respect to the displacement directions (A2, B2) of the cam element (102, 202 ) - are arranged axially offset from one another. 7. Valve drive device (100, 200) according to claim 5 or 6, characterized in that at least one slideway (108a, 108b; 208a, 208b) opens into an annular slideway section (108c) or ring-segment-shaped slideway section (208c, 208d). 8. Valve drive device (100) according to claim 7, characterized in that the annular slideway section (108c) is arranged between the first slideway (108a) and the second slideway (108b), the first (108a) and the second slideway (108b) open into the ring-shaped slideway section (108c) on different sides. 9. Valve drive device (100, 200) according to one of claims 1 to 8, characterized in that the first shifting claw element (111a, 211a) and the second shifting claw element (111b, 211b) are formed by a - preferably one-piece - shift fork (110, 210). are. 10. Valve train device (100, 200) according to claim 9, characterized in that the shift fork (110, 210) via at least one - preferably a single - elastic transmission member (114, 214) with the pivot shaft (112, 212) is rotatably connected. 11. Valve drive device (100, 200) according to one of claims 3 to 10, characterized in that the elastic U transmission member (114, 214) is designed as a torsion spring (115, 215) or torsion bar spring. 12. Valve drive device (100, 200) according to any one of claims 3 to 11, characterized in that at least one elastic transmission element (114, 214) between two bearing bushes (116a, 116b; 216a, 216b) of the shift fork (110, 210) and / or the first shifting pawl member (111a, 211a) and the second shifting pawl member (111b, 211b) is disposed on the pivot shaft (112, 212). 13. Valve drive device (100, 200) according to one of claims 1 to 12, characterized in that the first shifting claw element (111a, 211a) and the second shifting claw element (111b, 211b) are arranged axially offset on the pivot shaft (112, 212). 14. Valve drive device (100, 200) according to one of claims 1 to 13, characterized in that two sliding blocks (109a, 209a; 109b, 209b) are provided, a first sliding block (109a, 209a) and a second sliding block (109b, 209b) - in at least one displacement direction (A2, B2) of the cam element (102, 202) - are arranged offset to one another. 15. Valve drive device (100) according to one of claims 1 to 14, characterized in that at least one slideway (108a, 108b) is firmly connected to the cam element (102) and that at least one sliding block (108a, 108b) corresponding to this slideway (108a, 108b) 109a, 109b) is arranged on a shifting claw element (111a, 111b). 16. Valve train device (200) according to one of Claims 1 to 15, characterized in that at least one slideway (208a, 208b) is arranged on a shifting claw element (211a, 211b) and that at least one sliding block corresponding to this slideway (208a, 208b). (109a, 109b) is firmly connected to the cam element (202). 6 sheets of drawings