EP3067524B1 - Positioning element for axial shifting of a cam assembly which can be moved along a camshaft axis - Google Patents

Description

The present invention relates to an actuating element for axially displacing a displaceably mounted camshaft or a camshaft section displaceably mounted on a shaft along the camshaft axis. Furthermore, the invention relates to a device for axially displacing a camshaft or a camshaft section, comprising an axially displaceable camshaft or an axially displaceable camshaft section, which or has one or more projections, and such an actuating element.

Camshafts have a number of cams that represent eccentric portions on the camshaft. The cams can either be fixedly arranged on the camshaft or on camshaft sections which can be applied in a rotationally fixed but axially displaceable manner to a cylindrical shaft. With the cams adjacent axially displaceable components can be moved by turning the camshaft at regular intervals. A prominent application of the camshafts is thereby the opening and closing of valves in an internal combustion engine. In modern internal combustion engines, it is possible to change the engine characteristics, for example, from a comfort-oriented to a sporty characteristic, which, inter alia, by changing the valve lift caused by the Shape of the cam is determined, is implemented. In addition, different engine speeds require variable valve lifts to optimize torque and fuel consumption. Other internal combustion engines have a cylinder deactivation in which some of the cylinders may be shut down to save fuel. In this case, the valves of the deactivated cylinders need not be opened at all. Again, it is advantageous not only disable individual cylinders, but also variable valve lifts for the reasons mentioned above. Such internal combustion engines require camshafts having cams of different size and shape. A camshaft portion for such a camshaft is in FIG. 1 shown whose lateral surface can be divided into three sections. In a first section is a first cam, which opens a valve of an internal combustion engine with a first lift curve. In a second section is a second cam, which is smaller in comparison to the first cam and has a different geometry, and thus the valve when turning the camshaft with a second lift curve compared to the first lift curve less far and for a shorter time with a other speed profile opens. There is no cam at all in a third section, so that a valve which cooperates with the first section is not actuated at all during rotation of the camshaft, which is the case, for example, when the cylinder is switched off. The in FIG. 1 shown camshaft portion each has two of these sections, so that two of these camshaft sections must be provided for a four-cylinder internal combustion engine.

However, in order to open and close the valve with the different lift curves, the camshaft or the camshaft section must be moved axially to allow each of the corresponding cam to interact with the valve. In known solutions, for example, in the DE 10 2007 307 232 A1 , of the EP 2 158 596 B1 and the DE 10 2013 102 241 A1 are described, the camshafts on different grooves, in which engages an actuator with a different number of plungers. The grooves are doing a guide portion and together with the engaging rams form a slotted guide for the axial adjustment of the camshaft, which must be rotated by a certain amount for this purpose. Other adjusting elements for axial displacement of a along a camshaft axis slidably mounted camshaft are in the DE 10 2007 010 152 A1 , of the DE 10 2007 010 151 A1 and the DE 10 2011 054 218 A1 described.

Since the plungers of the actuators have to be moved back and forth coordinated with each other, the actuators are constructed relatively complicated. In addition, the grooves must be milled into the camshaft, which is therefore particularly associated with a considerable manufacturing effort, since a separate groove is provided for each plunger, which also each have their own cross-section. In addition, the camshaft is weakened in the area in which the grooves are arranged, which increases the likelihood of breakage in this area. This probability is increased by voltage spikes caused by the grooves.

Object of the present invention is therefore to provide an arrangement with which a camshaft can be moved axially in a structurally simple manner.

The object is achieved with an actuating element according to claim 1 and with a device according to claim 10. Advantageous embodiments emerge from the dependent claims.

According to the invention, the adjusting element is movable between a first position and a second position, wherein the actuating element has a guide portion, cooperate with the one or more projections of an axially displaceably mounted camshaft or an axially displaceably mounted camshaft portion in the first position so that the camshaft or the Camshaft portion is axially displaceable by rotating about the camshaft axis, and the projection in the second position does not cooperate with the guide portion. It is not excluded that the actuator can also be placed in other positions. The decisive factor is that at least in one position the projections can interact with the actuator and in another position no interaction is possible. An essential aspect of the present invention is that the guide portions are not arranged on the camshaft itself, as is the case in the prior art, but on the actuator. The actuator can be designed so that even guide sections with a more complicated geometry can be made relatively easy. The camshaft itself need not be provided with grooves or the like, but it is sufficient to provide a projection which cooperates with the guide portion of the actuating element when this is in the first position. As a result, the production of the camshaft is significantly simplified, so that an axial displacement of the camshaft or the camshaft section can be realized in a particularly cost-effective manner. In addition, the camshaft is not weakened by grooves, so that it is more stable overall and the likelihood that the camshaft breaks, is reduced.

The axial displacement of the camshaft or the camshaft section takes place in the following manner: The actuator is moved to the first position, in which the projection cooperates with the actuating element. Subsequently, the camshaft is rotated by a certain amount, for example, 90 °, wherein the projection moves along the guide portion so that the shape of the guide portion dictates the amount and motion profile of the axial displacement of the camshaft or camshaft portion along the camshaft axis. Subsequently, the actuator is moved to the second position and the camshaft can be used as intended.

According to the invention, the guide section comprises one or more guide surfaces of the actuating element, which are inclined at least in sections with respect to a center plane of the actuating element. The median plane should be such that it divides the actuator into two substantially equal halves. According to the invention, the guide surfaces are the outer surfaces of the actuating element, which limit the actuating element to the outside. The guide surfaces thus enclose an angle with the median plane. As a result, when the actuator is in the first position, as the camshaft rotates about the camshaft axis, a force directed along the camshaft axis acts on the projection of the camshaft, thereby axially displacing the camshaft or camshaft portion. To equip the actuator with this functionality, only one guide surface, which does not have to have any special properties, is sufficient. In particular, it is not necessary to tune the projection on the guide portion, whereby it is possible to use the actuator flexible for a plurality of axially displaceable camshaft or camshaft sections. In addition, the production of the actuating element is particularly simple. In addition, it is possible to realize even more complicated movement profiles of the camshaft during axial displacement, for example, a relatively slow axial displacement at the beginning of the rotation of the camshaft about its own axis, which accelerates in the course of rotation.

In the control element according to the invention, the guide portion comprises a first guide surface and a second guide surface, wherein the first guide surface and the second guide surface are inclined in opposite directions with respect to the center plane. In this embodiment, it is possible to axially displace the camshaft or the camshaft section by rotating in the same direction both in the one first direction and in the second opposite direction. This works In a first adjustment step, a first projection with the first guide surface together, whereby the camshaft or the camshaft portion is axially displaced in the first direction. In the next adjustment step, a second projection cooperates with the second guide surface, whereby the camshaft or the camshaft portion is axially displaced in the opposite direction. The two projections can be arranged axially spaced on the camshaft. Between the two adjustment steps, the adjusting element is moved to the second position.

Alternatively, it is also possible to displace the adjusting element axially between two successive adjusting steps, so that the same projection interacts with the first guide surface for adjustment in the one direction and with the second guide surface for returning. In this case, only one advantage is necessary.

According to the invention, the guide section has one or more guide grooves, which are inclined at least in sections relative to a center plane. In contrast to the guide surfaces, the guide grooves have the advantage that they can transmit axial forces relative to the camshaft axis along both directions. As a result, a forced operation or a slotted guide is realized. Thus, it is possible to axially advance the camshaft or camshaft section with a projection engaging a guide groove by rotating in one direction and axially pushing back by rotating in the opposite direction. In addition, it is possible to realize even more complicated motion profiles of the camshaft or the camshaft portion during axial displacement, for example, a relatively slow axial displacement at the beginning of the rotation of the camshaft about its own axis, which accelerates in the course of rotation. According to the invention, the guide section has a first guide groove and a second guide groove, wherein the first guide groove and the second guide groove are inclined in opposite directions with respect to the center plane. As already explained with respect to the guide surfaces, it is possible here to achieve an axial displacement of the camshaft or of the camshaft section in one direction as well as in the other direction by turning the camshaft in the same direction. In this case, two or more substantially mutually parallel first and second guide grooves may be provided. This makes it possible to advance the camshaft or the camshaft section stepwise axially with intermediate positions and then push back again.

Preferably, the first guide groove and the second guide groove intersect. In this way it can be achieved that the camshaft can be displaced axially by turning in the same direction with a projection both one and in the opposite direction. The two guide grooves can be designed so that the projection is axially positioned after passing through the first guide groove, that it then engages in the second guide groove, without the actuator must be axially displaced or a second projection must be provided. In this way, a very compact actuator can be provided, which allows the displacement of the camshaft or the camshaft portion in both directions with only one projection, without the actuator must be arranged axially displaceable. Consequently, a very cost-effective and mechanically simple camshaft displacement can be realized.

In a preferred embodiment, the first guide groove has a first cross section and the second guide groove has a second cross section which differs from the first cross section. This embodiment is particularly suitable when a plurality of first guide grooves and a plurality of second guide grooves are provided. In particular, when the guide grooves have different depths, the actuator can be moved a little further to the camshaft, for example, during axial advancement of the camshaft or the camshaft portion, so that the projection of the deeper groove is clearly guided even at crossing points. When pushing back the camshaft or the camshaft section then the actuator is moved slightly less far to the camshaft, so that the projection is guided only by the less deep groove and does not intervene in the deeper groove at the intersection. Consequently, then there are several first positions in which the projection can interact only with a specific groove. Alternatively, multiple protrusions of different sizes may be used.

In addition, it is possible to use the same actuator for different camshafts, which are provided with projections of different sizes, which may be due, for example, the different axial forces acting to adjust the camshaft. In this case, too, it is ensured that a first projection, which protrudes radially beyond the camshaft, actually extends only in the guide groove provided for it and does not erroneously jump into another guide groove at the point of intersection. Another projection, for example, projecting less far beyond the camshaft but having a larger diameter than the first projection, can thus be prevented from interfering with a wrong guide groove.

It has proven to be advantageous if the guide grooves have a first end and a second end, wherein the guide grooves in the region of the first end have an initial depth and leak in the region of the second end to zero. In other words, the depth of the guide groove should be gradual lose weight. In this case, the actuator is displaced from the projection itself from the first position toward the second position when the projection passes through the guide grooves. This allows a purely mechanical return to the second position can be achieved. Furthermore, it is prevented that the projection abuts against the groove end and is thus subjected to shear, which could lead to breakage of the projection. In addition, this ensures that the projection is no longer guided by the guide grooves when the camshaft or the camshaft portion has been moved to the desired axial position. It is prevented that tilted due to manufacturing inaccuracies or misalignment of the projection in the groove and consequently the actuator could be reset only with increased force in the second position or even blocked.

In a further development, the adjusting element has a storage section, with which the adjusting element between the first position and the second position is rotatably storable. Although it would also be conceivable to move the adjusting element back and forth with a purely translatory movement between the first and the second position, the rotatable mounting has the advantage that the mounting can be kept simple and the adjustment path particularly short. In addition, only very small adjustment forces are necessary for moving the actuating element in this embodiment.

Preferably, the actuating element has a tubular curved section, in which the guide section is arranged. The cooperating with the actuating elements projection of the camshaft or the camshaft section moves on a circular path. In order for the projection to interact with the guide section, the guide section must also follow this circular path at least in sections. Will the actuator provided with a tubular curved portion, the adjusting element can be made to save material and be brought in the first position particularly close to the camshaft. Although it would also be possible to use a substantially cuboidal actuator having curved guide grooves, but this would increase the material consumption significantly. In order for the actuator does not collide with the camshaft, very long projections would have to be used in this case, which would then be heavily loaded on bending and shear, which increases the risk of breakage of the projection. In addition, the projection, which may be formed as a pin or pin, be stored or have a bearing engagement element with which it cooperates with the actuating element in order to reduce the forces and moments acting on the projection. Such a configuration of the projection can also be provided for the adjusting element according to the invention, but is in any case structurally complex. If the actuator is provided with a tubular curved portion, the projections for the reasons mentioned above only have to protrude radially over the camshaft over a short distance, which significantly reduces the risk of breakage due to bending and shearing loads, so that no additional measures for reducing the loads are required. As a result, the production cost is kept low.

It is preferred if the tubular curved section sweeps over a first angle of about 70 ° to about 110 ° or a second angle of about 160 ° to about 200 ° relative to a center plane of the actuating element. In particular, when the tubular arched portion covers an angle of 90 ° or 180 °, it can be manufactured particularly easy to manufacture. In addition, it is possible to connect a plurality of adjusting elements with each other, for example, two adjusting elements with a tubular curved portion which sweeps over an angle of 90 ° in order to obtain an actuating element whose tubular area 180 ° sweeps over, so that a modular structure is made possible. In addition, it is possible to provide two non-tangentially contacting, spaced adjusting elements, which cover an angle of 90 °. In particular, when the tubular arched portion covers an angle of 160 ° to 200 °, the actuator can be mounted with a arranged on the bisecting the first or second angle bearing portion. In this case, a rocker-like mounting of the actuating element is realized. The tubular arched portion is then divided by the storage portion into first and second subsections. In this case, the actuator can be moved not only between the first and the second, but between the second and a third position. In the first position, the projection can engage in the first subsection and in the third position in the second subsection. In the second position of the tubular curved portion extends approximately concentric with the camshaft axis, so that the projection does not cooperate with the guide portion. The actuator can be mounted so that when failure of a moving means with which the actuator is moved, it is ensured that the camshaft or the camshaft portion remain in a usable position or is reset in this. As a result, the internal combustion engine can continue to be operated and the camshaft or the camshaft section can be automatically returned to an uncritical position even if the movement device fails. This is particularly important in a cylinder deactivation, so that it is prevented that all cylinders can be switched off in case of failure of the moving device.

The engine will not be damaged and the vehicle will continue to function albeit limited, allowing the driver to visit the service unaided. The reliability is thereby increased.

Preferably, the actuating element has an actuating portion which cooperates with an actuator for moving the actuating element between the first position and the second position. In particular, when the actuating element is rotatably mounted, the actuator can move the actuating element between the first and the second position solely by pressing and / or pulling the operating section by utilizing the lever ratios with a very small adjusting force. A special embodiment of the actuating portion is not necessary. Furthermore, the actuator can be constructed very simply.

Furthermore, it is preferred if the actuating portion has a recess or a through hole, in which engages a plunger of the actuator. In this case, in contrast to the known from the prior art solutions for moving a camshaft only a plunger is needed, which greatly simplifies the design of the actuator. When the plunger engages when adjusting the actuator in the recess or the through hole, it also serves to position the actuator and can also absorb forces, so that the actuator is additionally stabilized.

The object is further achieved by a device for axially displacing a camshaft or a camshaft section, which has an axially displaceable camshaft or an axially displaceable camshaft section, which has one or more projections, and an actuating element according to one of the preceding embodiments. The advantages and technical effects which are achieved with the device according to the invention, correspond to those which have been explained for the adjusting element according to the invention. In summary, it should be noted at this point that it is possible with the device according to the invention to design the axial adjustment of a camshaft or of a camshaft section in a particularly simple manner, in particular, because the camshaft does not have to be provided with difficult to be produced guide grooves, which also weaken the camshaft at this point. Rather, it is sufficient to provide the camshaft or the camshaft section with a projection or to use a projection already present on the camshaft or the camshaft section, namely one of the cams, for the axial displacement of the camshaft. The projection may have any shape and may, for example, also angled contours, which are comparable to a finger follower include.

Preferably, the guide portion comprises one or more guide surfaces of the actuator, which are at least partially inclined with respect to a center plane of the actuator and the actuator is arranged with respect to the camshaft so that the center plane is substantially parallel to a plane perpendicular to a camshaft axis extending camshaft plane , In this embodiment, it is ensured that the guide surfaces include a certain angle with respect to a camshaft plane extending perpendicular to the camshaft axis, so that a force acting parallel to the camshaft axis is exerted on the projection when the camshaft is rotated and the actuator is in the first position , By this axially acting force, the camshaft or the camshaft portion is moved along the camshaft axis.

The guide section preferably has one or more guide grooves which are inclined at least in sections relative to a center plane, wherein the actuating element is arranged with respect to the camshaft such that the midplane extends substantially parallel to a camshaft plane extending perpendicular to a camshaft axis. This also ensures that when rotating the camshaft, an axial force exerted by the guide grooves on the projection is, whereby the camshaft or the camshaft portion is axially displaced.

Preferably, the actuating element has a bearing portion, with which the adjusting element about an axis of rotation between the first position and the second position is rotatably storable, wherein the axis of rotation is substantially parallel to the camshaft axis. Characterized in that the axis of rotation about which the adjusting element is rotatably mounted, parallel to the camshaft axis, it is ensured that the projection can cooperate with the entire guide portion when the actuator is in the first position. In addition, this ensures that the camshaft or the camshaft section is axially adjusted in the desired manner.

Furthermore, the device may comprise an actuator which cooperates with an actuating portion of the actuating element for moving the actuating element between the first position and the second position. With an actuator, it is possible to move the actuator in the desired manner between the first and the second position. In particular, the actuator can be integrated into a control and regulating circuit of an internal combustion engine so that the camshaft or the camshaft section can be displaced axially in one direction or the other due to a specific event.

Preferably, the projection or projections are formed by cams of the camshaft or by the camshaft section. In this case, the camshaft or not at all made to be able to be axially displaced with the device according to the invention, since the cams themselves can interact with the actuator so that an axial adjustment of the camshaft or camshaft section is possible. An additional manufacturing effort on the camshaft or on the camshaft section is not necessary. consequently can the camshaft produce particularly favorable, without having to give up the axial displacement.

In an alternative embodiment, the projection is designed as a pin mounted in the camshaft or in the camshaft section. In contrast to the embodiment in which the cams themselves form the projection, although an additional manufacturing effort is necessary to secure the pin in the camshaft or in the camshaft section, but clearly compared to the known in the art, axially displaceable camshaft is lower, since the camshafts according to the invention need not be provided with a complicated groove. The manufacturing effort for attaching the pin in the camshaft or in the camshaft section is comparatively small. As an alternative to the pin, a bolt or a pin can be used. The pin can be formed by the main body of the camshaft or the camshaft section, so that it does not represent a separate component.

In this case, the pin can be rotatably mounted in the camshaft or in the camshaft section. As the pin is moved along the guide portion as the camshaft rotates, the pin slides on the guide portion, creating friction between the pin and the guide portion, which can result in abrasion of the pin and guide portion. If the pin is not rotatably mounted in the camshaft or in the camshaft section, the abrasion always occurs in the same area, so that the abrasion flattening the pin in the respective areas, which over time can lead to breakage of the pin. In addition, the degree of axial displacement of the camshaft or the camshaft portion is changed by the abrasion, so that the desired interaction of the cam with the valve can no longer be guaranteed. In addition, the abrasion can interfere with the operation of the Camshaft and the device according to the invention affect. If, however, the pin is rotatably mounted, the pin is rubbed off evenly, so that no flattening arise. Furthermore, the abrasion can be reduced by the fact that the pin does not slide along the guide portion, but rolls on the guide portion. The rolling can be promoted by roughening the contact areas between the pin and the guide portion.

• Bewegen eines Stellelements zwischen einer ersten Stellung und einer zweiten Stellung derart, dass ein Führungsabschnitt des Stellelements in der ersten Stellung mit einem oder mehreren der Vorsprünge der Nockenwelle oder des Nockenwellenabschnitts so zusammenwirkt, dass die Nockenwelle oder des Nockenwellenabschnitts durch Drehen um die Nockenwellenachse axial verschiebbar ist, und der Vorsprung in der zweiten Stellung nicht mit dem Führungsabschnitt zusammenwirkt.

Moreover, the invention relates to a method for axially sliding a camshaft axially displaceably mounted along a camshaft axis or a camshaft section displaceably mounted along the camshaft axis, wherein the camshaft has one or more projections, comprising the following step:

• Moving an actuator between a first position and a second position such that a guide portion of the actuator in the first position cooperates with one or more of the projections of the camshaft or camshaft portion such that the camshaft or camshaft portion is axially displaceable by rotating about the camshaft axis , and the projection in the second position does not cooperate with the guide portion.

Furthermore, the invention relates to the use of an actuating element and a device according to one of the embodiments described above for axially displacing a camshaft slidably mounted along a camshaft axis or a camshaft section displaceably mounted along the camshaft axis.

The advantages and technical effects achieved with the method according to the invention and the use according to the invention are, correspond to those which have been explained for the actuator according to the invention.

• Figur 1 einen Nockenwellenabschnitt nach dem Stand der Technik,
• Figur 2 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Stellelements,
• Figur 3 ein erstes Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung mit dem in Figur 2 gezeigten Stellelement,
• Figur 4 ein zweites Ausführungsbeispiel der erfindungsgemäßen Vorrichtung mit einem Stellelement gemäß einem zweiten Ausführungsbeispiel,
• Figur 5 ein drittes Ausführungsbeispiel eines erfindungsgemäßen Stellelements, und
• Figur 6 ein drittes Ausführungsbeispiel der erfindungsgemäßen Vorrichtung mit dem in Figur 5 gezeigten Stellelement.

The present invention will be explained below in detail by means of preferred embodiments with reference to the attached drawings. Show it

• FIG. 1 a camshaft section according to the prior art,
• FIG. 2 a first embodiment of an actuating element according to the invention,
• FIG. 3 a first embodiment of a device according to the invention with the in FIG. 2 shown actuator,
• FIG. 4 A second embodiment of the device according to the invention with an actuating element according to a second embodiment,
• FIG. 5 a third embodiment of an actuating element according to the invention, and
• FIG. 6 a third embodiment of the device according to the invention with the in FIG. 5 shown actuator.

FIG. 1 shows a camshaft portion 10 of the prior art. The camshaft section 10 shown here has a substantially hollow-cylindrical main body 12 with a lateral surface 14, which can also be manufactured as a solid cylinder, not shown. If the base body 12 is made as a solid cylinder, it forms the essential part of a camshaft, not shown here. Alternatively, you can a about a camshaft axis A _N rotatably mounted cylindrical shaft 15 (see. FIG. 4 ), on which the camshaft section 10 is mounted axially displaceable along the camshaft axis A _N. In this case, the shaft 15 and the camshaft portion 10 form the essential parts of a camshaft. At regular intervals, the main body 12 disk-shaped portions 16 which serve to reinforce the body and can be used for the storage of the camshaft portion 10.

Furthermore, on the lateral surface 14 there are three sections 18, namely a first section 18 ₁ , on which a first cam 20 is located, a second section 18 ₂ , on which a second cam 22 is arranged, and a third section 18 ₃ , on which is arranged no cam at all. The first cam 20 actuates an unillustrated valve of an internal combustion engine, also not shown, with a first lift curve, while the second cam 22 actuates the valve with a second lift curve, whereby the valve is opened less widely and for a shorter time than with the first lift curve. There is no cam at all in the third section 18 ₃ , so that a valve which cooperates with the third section 18 ₃ is not actuated at all when the camshaft section 10 is rotated, which is the case, for example, in the case of a deactivated cylinder. The number of sections 18 is chosen only as an example. In principle, the number of sections 18 can be chosen freely, but is limited in practice by the available space.

With the different lifting curves, the internal combustion engine can be operated with different characteristics, for example in a comfort-oriented or a sporty mode. In order to operate the engine in the various modes or to completely shut off a cylinder, the camshaft portion 10 must be along the camshaft axis A _{N are} axially displaced, so that the valve with one of the three sections 18 ₁ to 18 ₃ on the lateral surface 14 of the camshaft portion 10 can cooperate.

In FIG. 2 a first embodiment of an actuating element according to the invention 24 _{1 is shown} with reference to a perspective view. The adjusting element 24 ₁ according to the invention has a tubular curved section 26 and a storage section 28. The storage section 28 is designed approximately hollow cylindrical, so that the adjusting element 24 ₁ can be rotatably supported about a rotational axis A _D. The bearing can also be designed so that the actuator 24 ₁ along the axis of rotation A _{D is} displaced, but this is not required. The tubular curved section 26 is subdivided into two substantially equal halves from a central plane E, which runs essentially perpendicular to the axis of rotation A _D. Furthermore, positioning element 24 _1, the present invention has a number of guide portions 30 which are formed in the illustrated example of guide surfaces 32 and guide grooves 34th Concretely, the actuating element 24 _{1 has} a first guide surface 32 ₁ and a second guide surface 32 ₂ , which at the same time constitute the left and right outer surfaces of the tubular curved section 26 of the actuating element 24 ₁ relative to the center plane E. The first and the second guide surface 32 ₁ , 32 ₂ are inclined with respect to the center plane E by a certain angle, wherein the distance between the two guide surfaces 32 ₁ , 32 _{2 increases} with increasing distance from the axis of rotation A _D. Consequently, the tubular curved portion 26 has a trapezoidal shape in its development.

Furthermore, on the concave side of the tubular arched portion 26, two first guide grooves 34 ₁ and two second guide grooves 34 ₂ which are respectively parallel to each other and also inclined with respect to the center plane E. But it is just as possible, the two first guide grooves 34 ₁ do not run parallel to each other, which may also apply to the second guide grooves 34 ₂ . In the example shown, the first guide surface 32 ₁ extend parallel to the first guide grooves 34 ₁ and the second guide surface 32 ₂ parallel to the second guide grooves 34 ₂ , where also other courses are conceivable. It is also possible to provide more than two first guide grooves 34 ₁ and two second guide grooves 34 ₂ .

The first guide grooves 34 ₁ and the second guide grooves 34 ₂ are oppositely inclined with respect to each other, so that some of the guide grooves 34 intersect within the tubular arched portion 26. The two first guide grooves 34 ₁ have a first cross section Q ₁ and the two second guide grooves 34 ₂ have a second cross section Q ₂ , wherein the second cross section Q _{2 is} wider than the first cross section Q ₁ . In the example shown, both the first and the second guide grooves 34 ₁ , 34 _{2 have} a substantially rectangular cross-section. The guide grooves 34 each have a first end X ₁ and a second end X ₂ , wherein the first guide grooves 34 ₁ in the region of the first end X _1, a first initial depth T ₁ and the second guide grooves 34 ₂ there have a second initial depth T ₂ . The first initial depth T ₁ is less than the second initial depth T ₂ , wherein the depths of the first and second guide grooves 34 ₁ , 34 ₂ decrease with increasing distance from the storage section 28 and leak to zero.

In FIG. 3 a first embodiment of a device according to the invention 36 _{1 is shown} with reference to a perspective view. The device 36 ₁ comprises an axially displaceable along the camshaft axis A _N camshaft portion 10 and the in FIG. 2 shown actuator 24 ₁ . The camshaft portion 10 is substantially identical to that in the FIG. 1 is shown, however, has two projections 38 which are arranged in one of the disk-shaped sections 16. Specifically, the two projections 38 are realized as a first pin 40 and a second pin 42 which are radially projecting to a certain extent on the disc-shaped portion 16 and, for example, as hardened pins 40, 42 are formed. The two pins 40, 42 are pressed into the camshaft section 10 and aligned with each other. However, it is not necessary that the pins 40, 42 are aligned with each other when the guide portions 30 are carried out accordingly. In FIG. 3 is clearly visible that the tubular curved portion 26 sweeps over a lying in the center plane E angle of about 90 °. Furthermore, it can be seen that the axis of rotation A _D , about which the adjusting element 24 _{1 is} rotatably mounted, and the camshaft axis A _{N are} parallel. In addition, a comparison of the Figures 2 and 3 in that the adjusting element 24 ₁ is arranged with respect to the camshaft section 10 such that the median plane E runs parallel to a plane perpendicular to the camshaft axis A _N. The adjusting element 24 ₁ can be mounted, for example, on the cylinder head or on the valve train of the internal combustion engine or on the engine cover.

The actuator 24 ₁ is moved with a plunger 44 of an actuator 45 shown only greatly simplified between a first position and a second position. The actuator may comprise an electromagnet, wherein only one plunger 44 is sufficient to realize more complicated Verstellabfolgen the camshaft section 10. The first position should be defined so that at least one of the pins 40, 42 cooperates with the actuator 24 ₁ , whereas the second position should be defined so that none of the pins 40, 42 cooperates with the actuator 24 ₁ . However, the first position may change during the displacement of the camshaft section 10. To move the actuator 24 ₁ between the first and the second position, the plunger acts 44 with an actuating portion 46 together, which has a recess 48 in the present example, in which the plunger 44 engages. As a result, the plunger axially on the actuator 24 ₁ acting forces. Further, not shown here bearings of the actuating element 24 ₁ for receiving axially acting forces are conceivable. Alternatively, the actuating portion 46 may have a through bore. In principle, however, the plunger 44 can also engage at any other point of the tubular curved section 26.

In FIG. 3 is the actuator 24 ₁ in the second position, so that neither of the two pins 40, 42 cooperates with the actuator 24 ₁ . If the plunger 44 is displaced from the actuator 45 to the camshaft axis A _N toward the first position, one of the two pins 40, 42 cooperates either with one of the guide surfaces 32 or one of the guide grooves 34. In both cases, the pins 40, 42 pass through the guide surfaces 32 or the guide grooves 34 from the bearing portion 28 to the actuating portion 45 when the camshaft portion 10 is rotated approximately 90 degrees. As a result, one of the pins 40, 42 slides along one of the guide surfaces 32 or one of the guide grooves 34, thereby selecting a force acting along the camshaft axis A _N on the respective pin 40, 42 due to its inclination with respect to the center plane E not shown is applied, so that the camshaft portion 10 is axially displaced along the camshaft axis A _N. If the camshaft portion 10 has been moved to the desired axial position, the actuator 24 _{1 is moved} back to the second position.

The in FIG. 1 shown camshaft portion 10 has three sections 18 ₁ to 18 ₃ . When the camshaft portion 10 is in an axial position in which the first cam 20 cooperates with the valve of the engine, but the engine characteristic is to be changed, so the actuator 24 _{1 is moved up} to the camshaft portion 10, so that the pin 42 in the related to FIG. 2 right of the two first guide grooves 34 ₁ engages. If the pin 42 by turning the camshaft portion 10 through the right first guide groove 34 ₁ , so the camshaft portion 10 is in an axial position in which the second cam 22 cooperates with the valve. If now a cylinder are turned off, the adjusting element 24 _{1 is moved up} again to the camshaft section 10, wherein the inclination of the guide grooves 34 is selected so that the pin 42 engages after passing through a guide groove 34 in the next guide groove 34. In this case, the pin 42 then engages the left of the first guide grooves 34 ₁ , so that the camshaft portion 10 is further axially displaced in the same direction that the portion 18 ₃ cooperates with the valve. If the camshaft section 10 is to be pushed back axially, then either the first pin 40 is used by a corresponding rotation of the camshaft section 10, which protrudes a little further beyond the lateral surface 14 in comparison to the second pin 42, or the actuating element 24 ₁ becomes slightly further on Camshaft section 10 moved up and brought back the second pin 42 into engagement. This ensures that the pins 40, 42 are guided only by the lower second guide grooves 34 ₂ . A further axial displacement of the camshaft section 10 can also take place via the guide surfaces 32 ₁ and 32 ₂ .

As described above, the guide grooves 34 extend to zero with increasing distance from the rotation axis A _D. As a result, a radius reduction of the guide grooves 34 is achieved, which has the effect that the actuator 24 _{1 is} rotated away from the camshaft portion 10 when one of the pins 40, 42 passes through the guide grooves 34. The guide grooves 34 and the pins 40, 42 can be designed so that the actuator 24 _{1 is} already in the second position, when the pins 40, 42 have completely passed through the guide grooves 34. In addition, the force acting on the actuator 24 ₁ weight force to move between the first and the second position by a corresponding arrangement of the actuating element 24 ₂ with respect to the camshaft portion 10 can be exploited. Alternatively, the actuator 24 ₁ can be pulled by the plunger 44 in the second position or a spring mechanism can be provided, which biases the actuator 24 in the first or second position, so that the plunger 44 has to apply only one-directional force, causing the Actuator 45 can be very simple. Alternatively, the actuator may also include a bistable solenoid.

In FIG. 4 is a second embodiment of the device according to the invention 36 _{2 shown} with an actuating element 24 ₂ according to a second embodiment with reference to a perspective view. Here it is readily apparent that a first and a second camshaft section 10 ₁ , 10 ₂ are pushed onto the rotatably mounted shaft 15, not shown, and together form the essential parts of a camshaft. Again, the camshaft axis A _N and the axis of rotation A _{D are} parallel to each other. Compared to the first embodiment, the adjusting element 24 _{2 is} configured slightly wider according to the second embodiment, wherein the tubular curved portion 26 in turn covers an angle of about 90 °. Due to the width of the actuating element 24 ₂ , the two camshaft sections 10 ₁ , 10 ₂ are moved axially with the same actuator 24 ₂ . For example, it is possible to shut off the cylinder cooperating with the first camshaft section 10 ₁ while changing the characteristic of the cylinder cooperating with the second camshaft section 10 ₂ . This applies to both the intake and exhaust camshafts. The axial displacement of the camshaft sections 10 ₁ , 10 ₂ along the camshaft axis A _N is done in the manner described above. In FIG. 5 a third embodiment of the actuator 24 according to the invention 24 _{3 is shown} with reference to a perspective view. The essential difference from the other two embodiments is that the tubular curved portion 26 has a first subsection 50 and a second subsection 52, each sweeping an angle of approximately 90 °, so that the actuator 24 ₃ according to the third embodiment a Angle of 180 ° sweeps over, so that the actuator 24 _{3 has} the shape of a groove or half-shell. The storage section 28 is located approximately in the middle of the tubular arched portion 26, where the two subsections 50, 52 abut one another.

FIG. 6 shows a third embodiment of the inventive device 36 ₃ with the in FIG. 5 shown actuator 24 ₃ , which cooperates with a camshaft portion 10. The camshaft section 10 has two pins 40, 42 which are in FIG. 6 are not recognizable and contrary to the in FIG. 3 embodiment shown are not aligned. In the third embodiment, the actuator 24 _{3 is} in the second position when the first subsection 50 and the second subsection 52 have the same distance to the camshaft section 10, so that the actuator 24 ₃ with none of the two pins 40, 42 cooperates. When the actuator 45 pulls the plunger 44 towards itself, the actuator 243 is rotated in a first direction about the axis of rotation A _D and the first subsection 50 of the tubular arched portion 26 cooperates with the in FIG. 6 rear pin 40 together. As the actuator 45 pushes the plunger 44 away from itself, the actuator 243 is rotated in the opposite direction about the axis of rotation AD so that the front pin 42 engages the guide grooves 34 of the second subsection 52 of the tubular arched portion 26. by virtue of the rocker-like movement of the actuating element 24 ₃ , the second position is an intermediate position between the end positions of the actuating element 24 _3rd The axial displacement of the camshaft portion 10 along the camshaft axis A _{N also} happens here in the manner described above.

A shift is also possible in other ways: Depending on the configuration of the actuator 45, the zero position of the plunger 44 may be in the second position of the actuating element 24 ₃ when the actuator 45 is not activated. Consequently, the actuator 45 must be activated to rotate the actuator in one direction or the other about the axis of rotation A _D. However, it is also possible to design the actuator 45 in such a way that, when the actuator 45 is not activated, the actuating element is set to the first position, in which the rear pin 40 interacts with the first subsection 50. If no interaction takes place, then the actuator 45 must be activated so that it advances the plunger 44. In the event that the rear pin 40 cooperates with the first subsection 50, the actuating element 24 _{3 can} be rotated such that the rear pin 40 also interacts with the actuating element 24 ₃ in the second subsection 52. Consequently, the rear pin 40 can not only pass through the first, but also the second subsection 52, so that a very large axial displacement of the camshaft or the camshaft section 10 is made possible with only one pin 40.

Another possibility would be to make the adjustment by means of an adjusting pin. By pressing or pulling the actuator key, one of the two mentioned quarter shells can be brought into engagement. For example, in this embodiment, a magnet may be formed pressing, which rotates the pin in a cam. The pin then rotates in the direction of track 26 and 50 and should not be engaged. The magnet is pressed. The half shell with Adjustment track is not engaged. If the adjustment pin passes through the axis of rotation 28, it can be inserted into the corresponding track on the second quarter shell and displaces the cam, for example, to the left. If the actuator is not actuated when meshing on the first half-shell in tracks 26 and 50, it is for example pushed to the right. Analogously, this happens with pulling variants.

LIST OF REFERENCE NUMBERS

10, 10 ₁ , 10 ₂

camshaft portion

12

body

14

lateral surface

15

wave

16

disc-shaped section

18 ₁ to 18 ₃

sections

20

first cam

22

second cam

24, 24 ₁ to 24 ₃

actuator

26

tubular arched section

28

storage section

30

guide section

32, 32 ₁ , 32 ₂

guide surface

34, 34 ₁ , 34 ₂

guide

36, 36 ₁ to 36 ₃

contraption

38

head Start

40

first pen

42

second pen

44

tappet

45

actuator

46

actuating section

48

deepening

50

first subsection

52

second subsection

A _D

axis of rotation

A _N

camshaft axis

e

midplane

E _N

camshafts level

Q ₁

first cross-section

Q ₂

second cross section

T

initial depth

T ₁

first initial depth

T ₂

second beginning depth

X ₁

first end

X ₂

second end

Claims (18)

1. A positioning element for axially displacing a camshaft supported so as to be displaceable along a camshaft axis (A_N) or a camshaft section (10) supported on a shaft (15) so as to be displaceable along a camshaft axis (A_N), wherein

   - the positioning element (24) is movable between a first position and a second position,

   - the positioning element (24) includes a guide section (30), with which in the first position, one or more projections of a camshaft supported so as to be axially displaceable or of a camshaft section (10) supported so as to be axially displaceable cooperate in such a way that the camshaft or the camshaft section (10) is axially displaceable by rotation about the camshaft axis (A_N), and

   - in the second position, the projection (38) does not cooperate with the guide section (30),

   - the guide section (30) comprises one or more guide surfaces (32) of the positioning element (24), which are inclined at least in sections in relation to a central plane (E) of the positioning element (24), wherein the guide section (30) comprises a first guide surface (32₁) and a second guide surface (32₂), wherein the first guide surface (32₁) und the second guide surface (32₂) are inclined in opposite directions in relation to the central plane (E) and are the external surfaces of the positioning element (24), which limit the positioning element towards the outside,

   characterised in that the guide section (30) has one or more guide grooves (34) that are inclined at least in sections in relation to a central plane (E), and
   the guide section (30) has a first guide groove (34₁) and a second guide groove (34₂), wherein the first guide groove (34₁) and the second guide groove (34₂) are inclined in opposite directions in relation to the central plane (E) .
2. The positioning element as claimed in claim 1, characterised in that the first guide groove (34₁) and the second guide groove (34₂) intersect.
3. The positioning element as claimed in claim 2, characterised in that the first guide groove (34₁) has a first cross section (Q₁) and the second guide groove (34₂) has a second cross section (Q₂) that differs from the first cross section (Q₁).
4. The positioning element as claimed in any one of claims 1 to 3, characterised in that the guide grooves (34) have a first end (X₁) and a second end (X₂), wherein the guide grooves (34) have an initial depth (T) in the region of the first end (X₁) and run out to zero in the region of the second end (X₂).
5. The positioning element as claimed in any one of the preceding claims, characterised in that the positioning element (24) has a support section (28), by means of which the positioning element (24) can be rotatably supported between the first position and the second position.
6. The positioning element as claimed in any one of the preceding claims, characterised in that the positioning element (24) has a section (26) that is curved in a tubular manner, in which the guide section (30) is disposed.
7. The positioning element as claimed in claim 6, characterised in that the section (26) curved in a tubular manner sweeps a first angle of 70 to 110° or a second angle of 160 to 200° in relation to a central plane (E) of the positioning element (24).
8. The positioning element as claimed in any one of the preceding claims, characterised in that the positioning element (24) has an actuating section (46) that cooperates with an actuator (45) for moving the positioning element (24) between the first position and the second position.
9. The positioning element as claimed in claim 8, characterised in that the actuating section (46) includes an indent (48) or a through-bore that is engaged by a ram (44) of the actuator (45) .
10. A device for axially displacing a camshaft or a camshaft section (10), comprising

    - an axially displaceable camshaft or an axially displaceable camshaft section (10), which has one or more projections (38), and

    - a positioning element (24) as claimed in any one of the preceding claims.
11. The device as claimed in claim 10, characterised in that the guide section (30) comprises one or more guide surfaces (32) of the positioning element (24), which are inclined at least in sections in relation to a central plane (E) of the positioning element (24), and the positioning element (24) is disposed in relation to the camshaft or the camshaft section (10) in such a way that the central plane (E) extends substantially parallel to a camshaft plane (E_N) extending perpendicularly to a camshaft axis (A_N) .
12. The device as claimed in claim 10 or 11, characterised in that the guide section (30) has one or more guide grooves (34) that are inclined at least in sections in relation to a central plane (E), and the positioning element (24) is disposed in relation to the camshaft or the camshaft section (10) in such a way that the central plane (E) extends substantially parallel to a camshaft plane (E_N) extending perpendicularly to a camshaft axis (A_N).
13. The device as claimed in any one of claims 10 to 12, characterised in that the positioning element (24) has a support section (28), by means of which the positioning element (24) can be supported so as to be rotatable about a rotary axis (A_D) between the first position and the second position, wherein the rotary axis (A_D) extends substantially parallel to the camshaft axis (A_N).
14. The device as claimed in any one of claims 10 to 13, characterised in that the device comprises an actuator (45) that cooperates with an actuating section (46) of the actuating element (24) for moving the positioning element (24) between the first position and the second position.
15. The device as claimed in any one of claims 10 to 14, characterised in that the one or more projections (38) are formed by cams (20, 22) of the camshaft or by the camshaft section (10).
16. The device as claimed in any one of claims 10 to 15, characterised in that the projection (38) is formed as a pin (40, 42) that is fixed in the camshaft or in the camshaft section (10).
17. The device as claimed in claim 16, characterised in that the pin (40, 42) is rotatably supported in the camshaft or in the camshaft section (10).
18. A method for axially displacing a camshaft that is supported so as to be axially displaceable along a camshaft axis (A_N) or a camshaft section (10) supported so as to be displaceable along the camshaft axis (A_N), wherein the camshaft or the camshaft section (10) has one or more projections (38), comprising the following step:

    - moving a positioning element (24) as claimed in any one of claims 1 to 9 between a first position and a second position in such a way that in the first position, a guide section (30) of the positioning element cooperates with one or more of the projections (38) of the camshaft or of the camshaft section (10) in such a way that the camshaft or the camshaft section (10) can be axially displaceable by rotation about the camshaft axis (A_N), and in the second position, the projection (38) does not cooperate with the guide section (30).

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