Sliding cam system

Abstract

A sliding cam system for an internal combustion engine with an adjusting element (16), wherein the adjusting element (16) comprises at least three coupling pins (17a, 17b, 17c), wherein a first coupling pin (17a) is arranged in the region of the primary sliding cam element (12a), and a second coupling pin (17b) is arranged in the region of the first secondary sliding cam element (12b), and a third coupling pin (17c) is arranged in the region of the second secondary sliding cam element (12c), and the coupling pins (17a, 17b, 17c) interact in each case with a switching slotted guide (13) of the respective associated sliding cam element (12a, 12b, 12c) in such a way that a movement, initiated by an actuator pin (15), of a primary sliding cam element (12a) can be transferred by the adjusting element (16) to secondary sliding cam elements (12b, 12c), wherein the sliding cam system is set up in such a way that a switching operation of the first secondary sliding cam element (12b) takes place at least in part at the same time as the switching operation of the second secondary sliding cam element (12c).

Description

[0001] The invention relates to a sliding cam system for an internal combustion engine according to the preamble of claim 1.

[0002] A sliding cam system of the above-mentioned type is known, for example, from DE 10 2011 054 218 A1.

[0003] The known sliding cam system features a rotatably mounted camshaft. The camshaft comprises several sliding cams. The sliding cams are axially movable. The axial movement of the sliding cams is initiated by an actuator.

[0004] For this purpose, a coupling rod is firmly connected via a shift fork to a sliding cam, which is directly moved axially by the actuator. When the sliding cam moves axially, the coupling rod moves with the sliding cam.

[0005] The coupling rod comprises guides. The guides are firmly connected to the coupling rod. Each guide is assigned to a further sliding cam. The further sliding cams have pins that interact with the respective guides in such a way that the further sliding cams are moved according to the movement of the sliding cam firmly connected to the coupling rod.

[0006] From the applicant's patent application PCT / EP2020 / 058182 and DE 10 2019 107 626.9, a sliding cam system for an internal combustion engine with at least one camshaft has become known, comprising a carrier shaft with at least two sliding cam elements. The sliding cam elements each comprise a shift gate with at least one shift groove, wherein the sliding cam elements are axially displaceable relative to the carrier shaft by at least one actuator pin. At least one adjusting element is arranged parallel to a longitudinal axis of the carrier shaft, wherein the adjusting element is axially displaceable in the direction of the longitudinal axis of the carrier shaft.

[0007] Although an advantageous sliding cam system is already proposed here, improvements can still be made, particularly with regard to the maximum switching speed and the masses to be moved.

[0008] In the prior art, particularly in the sliding cam system according to PCT / EP2020 / 058182 or DE 10 2019 107 626.9, the displacement range of the switching grooves is limited to 120° NW each, which ultimately represents the groove length used for the displacement of the respective sliding cam element. The resulting kinematics, in turn, limit the masses to be moved by the sliding camshaft and ultimately the maximum switching speed.

[0009] This is where the present invention comes in and sets itself the task of providing an improved sliding cam system, in particular to specify a sliding cam system in which an axial displacement of a sliding cam element at an increased speed and / or an axial displacement of a sliding cam element with a greater mass can be achieved.

[0010] According to the invention, this object is achieved by a sliding cam system having the characterizing features of claim 1.

[0011] Because the sliding cam system is designed in such a way that a switching operation of a first secondary sliding cam element takes place at least partially simultaneously with the switching operation of a secondary sliding cam element, the displacement range can be increased and thus an axial displacement of a sliding cam element at an increased speed and / or an axial displacement of a sliding cam element with a greater mass can be achieved compared to a known sliding cam system.

[0012] Further advantageous embodiments of the proposed invention emerge in particular from the features of the subclaims. The subject matter and features of the various claims can, in principle, be combined with one another in any desired manner.

[0013] In an advantageous embodiment of the invention, it can be provided that the sliding cam system is configured such that the switching operation of a first secondary sliding cam element begins immediately after the end of the switching operation of the primary sliding cam element and that the switching operation of a second secondary sliding cam element begins after the start and before the end of the switching operation of the first secondary sliding cam element.

[0014] In a further advantageous embodiment of the invention, it can be provided that the sliding cam system is configured such that the start of the switching process of a first secondary sliding cam element and the start of the switching process of a second secondary sliding cam element occur simultaneously.

[0015] In a further advantageous embodiment of the invention, it can be provided that the length of the displacement areas of the sliding cam elements are equal, in particular that °NW 121a / S = °NW 121b / S = °NW 121c / S.

[0016] In a further advantageous embodiment of the invention, it can be provided that the length of the displacement ranges of all sliding cam elements is different, in particular that °NW 121a / S ≠ °NW 121b / S ≠ °NW 121c / S.

[0017] In a further advantageous embodiment of the invention, it can be provided that the displacement ranges of the sliding cam elements are greater than 120°NW, in particular that °NW 121a / S > 120° or °NW 121b / S > 120° or °NW 121c / S > 120°.

[0018] In a further advantageous embodiment of the invention, it can be provided that the start of the switching section °NW121b / SA to the cam start °NW122b / NA is not equal to the start of the switching section NW121c / SA to the cam start °NW122c / NA, in other words that the angular position of the displacement area to the respective cam tip is different for the secondary sliding cam elements, in particular that °NW121b / SA to °NW122b / NA is not equal to °NW121c / SA to °NW122c / NA.

[0019] In a further advantageous embodiment of the invention, it can be provided that the length of the displacement region of the first switching groove on the primary sliding cam element is greater than the length of the displacement regions of the switching grooves on the secondary sliding cam elements.

[0020] In a further advantageous embodiment of the invention, it can be provided that the length of the displacement range of the switching groove on at least one secondary sliding cam element is greater than the length of the displacement range on the primary sliding cam element and / or possibly further secondary sliding cam elements.

[0021] In a further advantageous embodiment of the invention, it can be provided that more than two secondary sliding cam elements are coupled to a connecting element.

[0022] In a further advantageous embodiment of the invention, it can be provided that the secondary sliding cam elements are not identical parts, in particular with regard to the sliding range and / or cam contour.

[0023] In a further advantageous embodiment of the invention, it can be provided that the cam contours of the secondary sliding cam elements are arranged identically, in particular, they are arranged offset at an angle only according to the firing order, e.g., offset by 120°, and are designed identically with regard to the cam contour. However, depending on the thermodynamic requirements, both the arrangement and the cam profile shape / cam profile length can differ.

[0024] In a further advantageous embodiment of the invention, the sliding cam system can be configured such that the switching operation of the primary sliding cam element is completed before the switching operation of a secondary sliding cam element occurs. Preferably, the primary sliding cam element is only displaced while the locking disc is released, and the secondary cam elements can preferably only be displaced when the locking disc is locked.

[0025] In a further advantageous embodiment of the invention, it can be provided that the sliding cam system is configured such that the switching operation of a first secondary sliding cam element begins immediately after the end of the switching operation of the primary sliding cam element, wherein in particular the switching operation of a further (second) secondary sliding cam element preferably begins after the start and before the end of the switching operation of the first secondary sliding cam element.

[0026] Further features and advantages of the present invention will become clear from the following description of preferred embodiments with reference to the accompanying drawings. Fig. 1 is a perspective view of an embodiment of a sliding cam system according to the prior art; Fig. 2 is a further perspective view of an embodiment of a sliding cam system according to the prior art; Fig. 3 is a side view of an embodiment of a sliding cam system according to the prior art; Fig. 4 is a further side view of an embodiment of a sliding cam system according to the prior art; Fig. 5 is a side view of another embodiment of a sliding cam system according to the prior art; Fig. 6 is a diagram "stroke [mm] / locking range [ ] over the angle [°NW]" for a sliding cam system according to the prior art; Fig. 7 is a perspective view of an embodiment of a sliding cam system according to the invention; Fig. 7a is a perspective view of a camshaft of an embodiment of a sliding cam system according to the invention;Fig. 8 shows a perspective view of a primary sliding cam element of a sliding cam system according to the invention; Fig. 9 shows a side view of a primary sliding cam element of a sliding cam system according to the invention; Fig. 10 shows a section AA according to . Fig. 9 ; Fig. 11 a first secondary sliding cam element of a sliding cam system according to the invention in a perspective view; Fig. 12 a first secondary sliding cam element of a sliding cam system according to the invention in a side view; Fig. 13 a section CC according to Fig. 12 ; Fig. 13a a section CC according to Fig. 12 ; Fig. 14 a second secondary sliding cam element of a sliding cam system according to the invention in a perspective view; Fig. 15 a second secondary sliding cam element of a sliding cam system according to the invention in a side view; Fig. 16 a section BB according to Fig. 15 ; Fig. 16a a section BB according to Fig. 15; Fig. 17 a locking element (locking disc) for a sliding cam system according to the invention; Fig. 18 a diagram "stroke [mm] / locking range [ ] over the angle [°NW]" for a sliding cam system according to the invention according to Fig. 7 .

[0027] The following reference symbols are used in the following figures: 10Camshaft 11Carrier shaft 12aPrimary cam element 12first secondary cam element 12cSecond secondary cam element 13Shift gate 14Shift groove 14aFirst shift groove 14bSecond shift groove 15Actuator pin 16Adjustment element 17aFirst coupling pin 17bSecond coupling pin 17cThird coupling pin 18Receiving element 19Locking element 20Rolling bearing 21Retaining rings 22Cam contour 23Actuator 24 Locking range of the locking disc 25 Full stroke profile of cylinder 1 (VH profile of cylinder 1) 26 Full stroke profile of cylinder 3 (VH profile of cylinder 3) 27 Full stroke profile of cylinder 2 (VH profile of cylinder 2) 28 Partial stroke profile of cylinder 1 (TH profile of cylinder 1) 29 Partial stroke profile of cylinder 3 (TH profile of cylinder 3) 30 Partial stroke profile of cylinder 2 (TH profile of cylinder 2) 31 Axial stroke of cylinder 1 32 Axial stroke of cylinder 2 33 Axial stroke of cylinder 3 34 Area of simultaneity of the axial movement of the secondary sliding cam elements (BG) 121aFirst switching groove of the primary sliding cam element 12a 121a'Second switching groove of the primary sliding cam element 12a 121bSwitching groove of the first secondary sliding cam element 12b 121cSwitching groove of the second secondary sliding cam element 12c 122a First cam contour of the primary sliding cam element 12a 122a' Second cam contour of the primary sliding cam element 12a 122b First cam contour of the first secondary sliding cam element 12b 122b' Second cam contour of the first secondary sliding cam element 12b 122c First cam contour of the second secondary sliding cam element 12c 122c' Second cam contour of the second secondary sliding cam element 12c °NW 121a / S Angular length of the displacement range 121a / S of the first switching groove 121a of the primary sliding cam element 12a °NW 121a / F Angular length of the freewheel 121a / F of the first switching groove 121a of the primary sliding cam element 12a °NW 121b / S Angular length of the displacement range 121b / S of the switching groove 121b of the first secondary sliding cam element 12b °NW 121b / F Angular length of the freewheel 121b / F of the switching groove 121b of the first secondary sliding cam element 12b °NW 121c / S Angular length of the sliding range 121c / S of the switching groove 121c of the second secondary sliding cam element 12c °NW 121c / F Angular length of the freewheel 121c / F of the switching groove 121c of the second secondary sliding cam element 12c °NW121a / SAStart of the displacement range of the first switching groove 121a of the primary sliding cam element 12a °NW121a / SEEnd of the displacement range of the first switching groove 121a of the primary sliding cam element 12a °NW121b / SAStart of the displacement range of the switching groove 121b of the first secondary sliding cam element 12b °NW121b / SEEnd of the displacement range of the switching groove 121b of the first secondary sliding cam element 12b °NW121c / SAStart of the displacement range of the switching groove 121c of the second secondary sliding cam element 12c °NW121c / SEEnd of the displacement range of the switching groove 121c of the second secondary sliding cam element 12c °NW122b / NABeginning of the first cam contour 122b of the first secondary sliding cam element 12b °NW122c / NABeginning of the first cam contour 122c of the second secondary sliding cam element 12c NS122b Cam tip of the first cam contour of the first secondary sliding cam element 12b NS122c Cam tip of the first cam contour of the second secondary sliding cam element 12c

[0028] The Figures 1 to 4 show the same embodiment of a sliding cam system from different perspectives.

[0029] The sliding cam system for an internal combustion engine with at least one camshaft 10 comprises a carrier shaft 11. A primary sliding cam element 12a and a first secondary sliding cam element 12b are arranged on the carrier shaft 11, axially movable relative to a longitudinal axis of the carrier shaft 11 and, in particular, rotationally fixed. It is conceivable for more than two sliding cam elements to be arranged on the carrier shaft 11. The carrier shaft 11 preferably comprises three rolling bearings 20. One rolling bearing 20 is arranged at each axial end of the carrier shaft 11, and another rolling bearing 20 is arranged between the sliding cam elements 12a, 12b. The rolling bearings 20 are preferably locked by retaining rings 21. The number of rolling bearings 20 and retaining rings 21, as well as the positions of the bearing points, are variable. The sliding cam elements 12a, 12b comprise a switching gate 13 and a cam contour 22.

[0030] The shift gate 13 of the first sliding cam element 12a comprises a first and a second shift groove 14a, 14b. The shift grooves 14a, 14b are V-shaped at least in sections. In other words, the width of the two shift grooves 14a, 14b is not constant. The width refers to the distance between the flanks of the shift grooves 14a, 14b in the axial direction from the support shaft 11. The flanks of the shift grooves 14a, 14b approach one another in the V-shaped section.

[0031] The two switching grooves 14a, 14b are preferably arranged at the same angle of rotation. The first switching groove 14a preferably has a larger radius than the second switching groove 14b.

[0032] The radius is the distance between the groove base surface of the first or second shift groove 14a, 14b and the central longitudinal axis of the support shaft 11. Thus, the outer diameter of the shift gate 13 and the radius of the groove base surface determine the groove depth.

[0033] The first shift groove 14a preferably includes a step. In other words, the first shift groove 14a is configured as a projection or a shoulder. The first shift groove 14a preferably has a varying radius. This means that the first shift groove 14a has sections with a larger radius and a smaller radius. The radius changes continuously. The sections are each assigned to an inward-facing region, an outward-facing region, or a displacement region.

[0034] The second shift groove 14b preferably has a constant radius. The width of the second shift groove 14b is smaller than the width of the first shift groove 14a.

[0035] Two actuator pins 15 are arranged on the support shaft 11. The actuator pins 15 are essentially only movable in a direction orthogonal to the central longitudinal axis of the support shaft 11. The actuator pins 15 are assigned to the first switching groove 14a. This means that the actuator pins only interact with the first switching groove 14a. The actuator pins 15 are spaced apart from one another in the axial direction of the support shaft 11. As a result, depending on the position of the primary sliding cam element, one of the two actuator pins 15 can be inserted into the first switching groove 14a. By inserting the actuator pins 15, an axial movement of the primary sliding cam element 14a can be initiated.

[0036] For this purpose, an actuator pin 15 is inserted into the first switching groove 14a. By reducing the groove width, the inserted actuator pin 15 interacts with a flank of the first switching groove 14a. More precisely, the inserted actuator pin 15 applies a force opposite to the flank to a flank of the first switching groove 14a. This causes the axial displacement of the primary sliding cam element 12a. The direction of the displacement thus depends on the flank with which the inserted actuator pin 15 interacts. Each flank of the first switching groove 14a is assigned an actuator pin 15.

[0037] An adjustment element 16 is arranged parallel to the support shaft 11. The adjustment element 16 is axially movable. The adjustment element is offset by 90° from the actuator pins 15. Alternatively, other angular offsets are conceivable. The adjustment element 16 comprises a first and a second coupling pin 17a, 17b and a receiving element 18. The first and the second coupling pin 17a, 17b are each arranged at an axial end of the adjustment element 16. The receiving element 18 comprises three extensions and is arranged between the axial ends of the adjustment element 16. The coupling pins 17a, 17b and the receiving element 18 extend orthogonally to the central longitudinal axis of the support shaft 11.

[0038] The first coupling pin 17a is associated with the second switching groove 14b of the primary sliding cam element 12a. The first and second coupling pins 17a, 17b are arranged substantially rotatably on the adjustment element 16. The first coupling pin 17a is permanently engaged with the second switching groove 14b of the primary sliding cam element 12a.

[0039] The first coupling pin 17a is subjected to a force by a flank of the second switching groove 14b. The adjustment element 16 is displaced in the direction of action of the force. Since the adjustment element 16 and thus the coupling pins 17a, 17b are offset from each other by 90° in the circumferential direction and the first and second switching grooves 14a, 14b are arranged at the same angle of rotation, the displacement of the adjustment element 16 occurs with a corresponding time offset or phase shift.

[0040] The second coupling pin 17b is arranged in the region of the first secondary sliding cam element 12b. The first secondary sliding cam element 12b comprises a switching groove 14. The switching groove 14 has a V-shaped section. The second coupling pin 17b is permanently engaged with the switching groove 14. The switching groove 14 of the first secondary sliding cam element 12b is arranged such that a switching of the first secondary sliding cam element 12b with a time offset from the primary sliding cam element 12a can be realized.

[0041] By moving the adjustment element 16, the second coupling pin 17b is moved axially in the switching groove 14. More precisely, the second coupling pin 17b is moved toward one of the flanks of the switching groove 14.

[0042] The second coupling pin 17b interacts with the switching groove 14 in essentially the same way as the actuator pins 15 interact with the first switching groove 14a of the primary sliding cam element 12a.

[0043] The support shaft 11 comprises a circular disk-shaped locking element 19. Other geometries are conceivable. The locking element 19 is arranged between the first and the first secondary sliding cam element 12a, 12b. The locking element 19 is axially delimited by the receiving element 18. The locking element 19 has a supporting function. The locking element 19 forms an abutment for the receiving element 18. The locking element 19 absorbs the forces during the switching process and thus enables the adjustment element 16 to be fixed. Furthermore, the interaction of the receiving element 18 and the locking element 19 prevents the primary sliding cam element 12a from being accidentally displaced. The receiving element 18 comprises two receptacles for the locking element 19. The locking element 19 comprises a recess. This allows the adjustment element to be displaced by the circular disk. For this purpose, the recess is arranged in the area of the corresponding angle of rotation.The recess is arranged in the circular disc in such a way that, upon axial movement, the adjusting element 16 is moved through the recess. It is conceivable that the adjusting element 16 additionally comprises a spring-ball locking mechanism (not shown).

[0044] In summary, the previously described sliding cam system enables phase-shifted switching of the sliding cam elements 12a, 12b using a single actuator via the adjusting element 16. This significantly reduces the total number of actuators in the sliding cam system.

[0045] Fig. 5 describes a further embodiment of a sliding cam system according to the prior art. The sliding cam system essentially corresponds to the sliding cam system according to the Figures 1 to 4. In contrast to the system described above, the sliding cam system shown comprises a second secondary sliding cam element 12c and, in particular, the primary sliding cam element 12a has a differently shaped switching gate.

[0046] The locking element 19 is preferably arranged between the second and third sliding cam elements 12b, 12c. The locking element 19 comprises a circular disc with a recess. An extension is arranged on the adjustment element 16 in the region of the circular disc. The circular disc forms an abutment for the extension. The circular disc interacts with the extension during a displacement process such that the first coupling pin is relieved of load during the displacement process. In other words, the extension is supported against the circular disc. The recess is arranged at the angle of rotation at which the displacement of the first adjustment element 16 occurs. An actuator is designated by the reference numeral 23.

[0047] In the Fig. 6 is "a diagram "Stroke [mm] / Locking range [ ] over the angle [°NW]" for a sliding cam system according to Fig. 5 " is shown.

[0048] In the diagram according to Fig. 6 are those resulting from the respective cam contours (large stroke) of the embodiment of a sliding cam system according to the prior art according to Fig. 5 The resulting valve lifts are shown as "VH profile cylinder 1", "VH profile cylinder 2" and "VH profile cylinder 3".

[0049] In the diagram according to Fig. 6 are those resulting from the respective cam contours (small stroke) of the embodiment of a sliding cam system according to the prior art according to Fig. 5 The resulting valve lifts are shown as "TH profile cyl. 1", "TH profile cyl. 2" and "TH profile cyl. 3".

[0050] In the diagram according to Fig. 6 The locking areas of the locking disc or locking element 19 are also shown.

[0051] For further details and also further embodiments, reference can be made to PCT / EP2020 / 058182 or DE 10 2019 107 626.9 of the applicant, to which reference is expressly made here.

[0052] Further improvements regarding the switching of the sliding cam elements are described below.

[0053] In the Fig. 7 to 18 A preferred embodiment of the present invention is shown. The embodiment of the sliding cam system according to the invention described therein comprises a primary sliding cam element 12a, a first secondary sliding cam element 12b, and a second secondary sliding cam element 12c. Furthermore, the locking element 19 can also be referred to as a locking disc. Furthermore, the adjusting element 16 can also be referred to as a push rod.

[0054] The sliding cam elements each have a switching groove 121a, 121a', 121b, 121c, ie the primary sliding cam element 12a has the switching groove 121a and 121a', the first secondary sliding cam element 12b has the switching groove 121b and the second secondary sliding cam element 12c has the switching groove 121c.

[0055] The switching groove 121a is provided for engagement of the actuator pins 15, whereas the switching groove 121a' is provided for engagement of the first switching pin 17a of the connecting element 16.

[0056] The switching groove 121b is correspondingly provided for the engagement of the second switching pin 17b and the switching groove 121c is correspondingly provided for the engagement of the third switching pin 17c.

[0057] The operating principle is as outlined above: the primary shift cam element 12a is axially displaced in a targeted manner via the actuator or the engagement of the actuator pins 15 in the switching groove 121a during the rotation of the camshaft 10. The adjusting element 16 is axially displaced via the engagement of the first switching pin 17a in the switching groove 121a', whereby the switching pins 17b and 17c are also displaced accordingly.

[0058] The switching groove 121a of the primary sliding cam element 12a has at least one displacement region 121a / S and one freewheel region 121a / F in the circumferential direction. The displacement region 121a / S is characterized in particular by a switching groove side cheek that is inclined to the longitudinal axis / rotational axis L of the primary sliding cam element 12a or carrier shaft. In other words, this is the region with which the primary element 12a and, through the operative connection between the switching groove 121a' and the switching pin 17a, the connecting element 16 are axially displaced. The freewheel region, in contrast, is the region of the switching groove 121a in which no axial displacement of the connecting element 16 takes place. The displacement region can also be referred to as the switching region.

[0059] The switching groove 121b of the first secondary sliding cam element 12b has at least one displacement region 121b / S and one freewheel region 121b / F in the circumferential direction. The displacement region 121b / S is characterized in particular by a switching groove side cheek that is inclined to the longitudinal axis / axis of rotation L of the secondary sliding cam element 12b or carrier shaft. In other words, this is the region against which a displaced switching pin 17b rests and axially displaces the secondary sliding cam element 12b in the desired direction. The freewheel region, in contrast, is the region of the switching groove 121b in which no axial displacement of the secondary sliding cam element 12b takes place. This region is characterized in particular by the fact that there is no contact with the switching groove side cheek during the movement of the connecting element.

[0060] To avoid repetition, it should be noted that the second secondary sliding cam element 12c and its switching groove 121c also have a sliding region 121c / S and a freewheel region 121c / F. The switching pin 17c of the adjusting element 16 engages here. Regarding the function, reference can be made to the previous paragraph regarding the first secondary sliding cam element 12b.

[0061] The sliding cam elements each have at least two cam contours. One cam contour can also be designed as a so-called zero-lift cam. The cam contours differ from one another and, in particular, lead to different lifts of the controlled valve (not shown).

[0062] The primary sliding cam element 12a preferably has a first cam contour 122a and a second cam contour 122a'. The first secondary sliding cam element 12b preferably has a first cam contour 122b and a second cam contour 122b'. The second secondary sliding cam element 12c preferably has a first cam contour 122c and a second cam contour 122c'. For the sake of clarity, Fig. 7 and 7a no cam contour of the primary sliding cam element 12a is drawn. However, here the Fig. 8 to 10 be referred to.

[0063] The displacement ranges can be defined in more detail with regard to their angular length as well as their start and end.

[0064] Thus, the angle lengths °NW 121a / S Angular length of the sliding range 121a / S of the first switching groove 121a of the primary sliding cam element 12a °NW 121a / F Angular length of the freewheel 121a / F of the first switching groove 121a of the primary sliding cam element 12a °NW 121b / S Angular length of the sliding range 121b / S of the switching groove 121b of the first secondary sliding cam element 12b °NW 121b / F Angular length of the freewheel 121b / F of the switching groove 121b of the first secondary sliding cam element 12b °NW 121c / S Angular length of the sliding range 121c / S of the switching groove 121c of the second secondary sliding cam element 12c °NW 121c / F Angular length of the freewheel 121c / F of the switching groove 121c of the second secondary sliding cam element 12c or start and end of the shift areas °NW121a / SAStart of the displacement range of the first switching groove 121a of the primary sliding cam element 12a °NW121a / SEEnd of the displacement range of the first switching groove 121a of the primary sliding cam element 12a °NW121b / SAStart of the displacement range of the switching groove 121b of the first secondary sliding cam element 12b °NW121b / SEEnd of the displacement range of the switching groove 121b of the first secondary sliding cam element 12b °NW121c / SAStart of the displacement range of the switching groove 121c of the second secondary sliding cam element 12c °NW121c / SEEnd of the displacement range of the switching groove 121c of the second secondary sliding cam element 12c as mentioned above.

[0065] According to the invention, the sliding cam system is configured such that a switching operation of the first secondary sliding cam element 12b takes place at least partially simultaneously with the switching operation of the second secondary sliding cam element 12c.

[0066] The partially simultaneous switching of the secondary sliding cam elements is understood according to the invention as follows: the displacement areas of the respective secondary sliding gates are angularly aligned to one another in such a way that they have sections in which the coupling pin of the adjusting element for axially displacing the first secondary sliding cam element and the coupling pin of the adjusting element for axially displacing the second secondary sliding cam element are in operative contact at the same time (in the same direction), so that an axial displacement of the second secondary cam element at least begins while the axial displacement of the first secondary sliding cam element takes place.

[0067] The angular alignment, i.e. the arrangement and length of the respective corresponding displacement ranges of the secondary gates, are always dependent on the design of the engine or the respective installation space requirements of the internal combustion engine, such as the radial arrangement and position of the adjustment element.

[0068] The angular alignment, i.e. the arrangement and length of the respective corresponding displacement ranges of the secondary gates, are always dependent on the design of the engine or the respective installation space requirements of the internal combustion engine, such as the radial arrangement and position of the adjustment element.

[0069] Preferably, it can be provided that the sliding cam system is configured such that the switching operation of the first secondary sliding cam element 12b begins immediately after the end of the switching operation of the primary sliding cam element 12a and that the switching operation of the second secondary sliding cam element 12c begins after the start and before the end of the switching operation of the first secondary sliding cam element 12b.

[0070] It can further preferably be provided that the sliding cam system is configured such that the start of the switching operation of the first secondary sliding cam element 12b and the start of the switching operation of the second secondary sliding cam element 12c occur simultaneously.

[0071] It can further preferably be provided that the radial length of the displacement ranges °NW121a / S, °NW121b / S and °NW121c / S (angular ranges) of all sliding cam elements 12a, 12b, 12c are of equal size, in particular that °NW121a / S = °NW121b / S = °NW121c / S.

[0072] It can further preferably be provided that the radial length of the displacement ranges °NW121a / S, °NW121b / S and °NW121c / S (angular ranges) of all sliding cam elements 12a, 12b, 12c is different, in particular that °NW121a / S ≠ °NW121b / S ≠ °NW121c / S.

[0073] It can further preferably be provided that the displacement ranges of the sliding cam elements are greater than 120°NW, in particular that °NW121a / S > 120° or °NW121b / S > 120° or °NW121c / S > 120°.

[0074] It can further preferably be provided that the sliding cam system is configured such that the offset of the switching section °NW121b / SA to the cam start °NW122b / NA is not equal to the offset of the switching section °NW121c / SA to the cam start °NW122c / NA.

[0075] It can further preferably be provided that the length of the displacement range °NW121a / S of the first switching groove 121a on the primary sliding cam element 12a is greater than the length of the displacement ranges °NW121b / S or °NW121c / S of the switching grooves 121b or 121c on the secondary sliding cam elements 12b or 12c.

[0076] Further preferably, it can be provided that the length of the displacement range °NW121b / S or °NW121c / S of the switching groove 121b or 121c on at least one secondary sliding cam element 12b or 12c is greater than the length of the displacement range °NW121a / S on the primary sliding cam element 12a and / or possibly further secondary sliding cam elements (°NW121x / S or 12x). The x here stands as an index for further secondary sliding cam elements.

[0077] Further preferably, it can be provided that more than two secondary sliding cam elements 12b, 12c are coupled to a connecting element 16, particularly in applications in internal combustion engines with more than three cylinders arranged in series. It can preferably be provided that the switching groove on a secondary sliding element is larger than on the primary sliding element and / or is larger than on at least one other secondary sliding element.

[0078] The sliding cam system is also applicable to 5, 6, 8, 10, and 12-cylinder internal combustion engines. The sliding cam system can also be configured with three stages (or more) based on the number of cam contours 122x y<. "X" stands here as an index for the respective sliding cam element, and "Y" stands here as an index for the respective cam contour.

[0079] In comparison to a sliding cam system according to the prior art, the present invention modifies the length as well as the arrangement of the sliding grooves (area of axial displacement) of the secondary switching gates with respect to the respective cam tip in such a way that ultimately an overlapping switching of the secondary elements is achieved.

[0080] This can lead to an angular length of the displacement range 121a / S of the primary sliding cam element 12a, as well as the secondary sliding cam elements 12b and 12c, of °NW121a / S > 120°, an angular length of the displacement range 121b / S of the first secondary sliding cam element 12b of °NW121b / S > 120° and / or an angular length of the displacement range 121c / S of the second secondary sliding cam element 12c of °NW121c / S > 120°, in particular to an angular length °NW121a / S, °NW121b / S, °NW121c / S of the displacement ranges 121a / S, 121b / S, 121c / S of the switching grooves 121a, 121b, 121c of, for example, 153°NW.

[0081] It can further preferably be provided that the angular position of the displacement area to the respective cam tip for the secondary sliding cam element is different, in particular that °NW121b / SA to °NW122b / NA is not equal to °NW121c / SA to °NW122c / NA.

[0082] It may further preferably be provided that secondary sliding cam elements are not identical parts, in particular with regard to the displacement range (arrangement, length) and / or cam contour (arrangement, length).

[0083] The arrangement of the shift areas relative to the respective cam tip should be different, and the length can be different. If the secondary cams have different mass properties, the switching behavior can be adjusted, for example, by adjusting the length of the switching grooves to the mass.

[0084] In a specific and preferred embodiment of the invention, it can be provided that the start of the switching section °NW121b / SA to the cam tip NS122b of the first secondary sliding cam is 143° and the start of the switching section NW121c / SA to the cam tip NS122c of the second secondary sliding cam is 203°, in other words that the angular position of the displacement range to the respective cam tip is different for the secondary sliding cam elements, in particular that °NW121b / SA to NS122b is not equal to °NW121c / SA to NS122c.

[0085] It may furthermore preferably be provided that the cam contours of the secondary sliding cam elements are arranged identically, in particular, they are only offset at an angle according to the firing order, e.g., offset by 120°, and are designed identically with regard to the cam contour. However, depending on the thermodynamic requirements, both the arrangement and the cam profile shape / cam profile length may differ.

[0086] In particular with regard to the "diagram "Stroke [mm] / Locking range [ ] over the angle [°NW]" for a sliding cam system according to the invention according to Fig. 7 " ( Fig. 18 ) it can be clearly seen that the switching process of the primary sliding cam element 12a should be completed before the switching process of a secondary sliding cam element 12b, 12c can take place. This is particularly due to the function of the locking disc 19.

[0087] Further with regard to the diagram according to Fig. 18It is clearly visible here that the switching process or the axial displacement of a first secondary sliding cam element 12b begins immediately after the switching process of the primary sliding cam element has ended. The switching process of a further (second) secondary sliding cam element preferably begins after the start and before the end of the switching process of the first secondary sliding cam element. In extreme cases, the first secondary sliding cam element and the further secondary sliding cam element(s) switch simultaneously - ie, the switching processes begin simultaneously.

[0088] In the diagram according to Fig. 18 The valve lifts resulting from the first cam contours 122a, 122b and 122c are shown as "VH profile cyl. 1", "VH profile cyl. 2" and "VH profile cyl. 3".

[0089] In the diagram according to Fig. 18The valve lifts resulting from the first cam contours 122a', 122b' and 122c' are shown as "TH profile cyl. 1", "TH profile cyl. 2" and "TH profile cyl. 3".

[0090] In the diagram according to Fig. 18 The locking areas of the locking disc or locking element 19 are also shown.

[0091] A "region of simultaneity of the axial movement of the secondary sliding cam elements" was also drawn as BG. Here, the overlap of the axial displacement of the secondary sliding cam elements, which is essential to the invention, can be seen.

[0092] It is further apparent, but not essential to the core of the invention, that the valve lifts resulting from the first cam contours 122a, 122b and 122c as "VH profile cyl. 1", "VH profile cyl. 2" and "VH profile cyl. 3" or the valve lifts resulting from the first cam contours 122a', 122b' and 122c' as "TH profile cyl. 1", "TH profile cyl. 2" and "TH profile cyl. 3" overlap in time.

Claims

1. A sliding cam system for an internal combustion engine having at least one camshaft (10), comprising a carrier shaft (11) with at least one primary sliding cam element (12a), a first secondary sliding cam element (12b) and at least one second secondary sliding cam element (12c) which each comprise a shifting gate (13) with at least one shifting groove (14), wherein the primary sliding cam element (12a) is displaceable axially with respect to the carrier shaft (11) by at least one actuator pin (15) and at least one adjusting element (16) is arranged parallel to a longitudinal axis of the carrier shaft (11), wherein the adjusting element (16) is displaceable axially in the direction of the longitudinal axis of the carrier shaft (11), wherein the adjusting element (16) has at least three coupling pins (17a, 17b, 17c), wherein a first coupling pin (17a) is arranged in the region of the primary sliding cam element (12a) and a second coupling pin (17b) is arranged in the region of the first secondary sliding cam element (12b) and a third coupling pin (17c) is arranged in the region of the second secondary sliding cam element (12c) and the coupling pins (17a, 17b, 17c) each cooperate with a shifting gate (13) of the respectively associated sliding cam element (12a, 12b, 12c) such that a movement of the primary sliding cam element (12a) initiated by the actuator pin (15) is transmissible to the secondary sliding cam elements (12b, 12c) by the adjusting element (16), characterized in that the sliding cam system is designed such that a shifting operation of the first secondary sliding cam element (12b) takes place at least partially at the same time as the shifting operation of the second secondary sliding cam element (12c).

2. The sliding cam system as claimed in claim 1, characterized in that the sliding cam system is designed such that the shifting operation of the first secondary sliding cam element (12b) begins immediately after the end of the shifting operation of the primary sliding cam element (12a), and in that the shifting operation of the second secondary sliding cam element (12c) begins after the beginning and before the end of the shifting operation of the first secondary sliding cam element (12b).

3. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the sliding cam system is designed such that the beginning of the shifting operation of the first secondary sliding cam element (12b) and the beginning of the shifting operation of the second secondary sliding cam element (12c) take place at the same time.

4. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the lengths of the displacement regions (°NW121a / S, °NW121b / S and °NW121c / S) of the sliding cam elements (12a, 12b, 12c) are the same, in particular in that °NW121a / S = °NW121b / S = °NW121c / S.

5. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the radial lengths of the displacement regions (°NW121a / S, °NW121b / S and °NW121c / S) of all the sliding cam elements (12a, 12b, 12c) are different, in particular in that °NW121a / S ≠ °NW121b / S ≠ °NW121c / S.

6. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the displacement regions (°NW121a / S, °NW121b / S and °NW121c / S) of the sliding cam elements (12a, 12b, 12c) are greater than 120°NW, in particular in that °NW121a / S > 120° and °NW121b / S > 120° and °NW121c / S > 120°, respectively.

7. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the sliding cam system is designed such that the beginning of the shifting portion °NW121b / SA with respect to the cam start °NW122b / NA is not the same as the beginning of the shifting portion °NW121c / SA with respect to the cam start °NW122c / NA.

8. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the length of the displacement region (°NW121a / S) of the first shifting groove (121a) on the primary sliding cam element (12a) is greater than the length of the displacement regions (°NW121b / S and °NW121c / S, respectively) of the shifting grooves (121b and 121c, respectively) on the secondary sliding cam elements (12b and 12c, respectively).

9. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the length of the displacement region (°NW121b / S or °NW121c / S, respectively) of the shifting groove (121b or 121c, respectively) on at least one secondary sliding cam element (12b or 12c, respectively) is greater than the length of the displacement region (°NW121a / S) on the primary sliding cam element (12a) and / or possibly further secondary sliding cam elements (°NW121x / S and 12x, respectively).

10. The sliding cam system as claimed in at least one of the preceding claims, characterized in that more than two secondary sliding cam elements (12b, 12c) are coupled to a connecting element (16).

11. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the secondary sliding cam elements are not identical parts, in particular in terms of the displacement region and / or cam contour.

12. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the cam contours of the secondary sliding cam elements are arranged identically, in particular are arranged so as to be offset at an angle, for example offset at 120°, only in accordance with the ignition sequence, and are embodied identically with regard to the cam contour.

13. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the sliding cam system is designed such that the shifting operation of the primary sliding cam element (12a) ends before the shifting operation of a second secondary sliding cam element (12b, 12c) takes place.

14. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the sliding cam system is designed such that the shifting operation of a first secondary sliding cam element (12b) begins immediately after the end of the shifting operation of the primary sliding cam element (12a), wherein in particular the shifting operation of a further (second) secondary sliding cam element (12c) begins preferably after the beginning and before the end of the shifting operation of the first secondary sliding cam element (12b).

15. The sliding cam system as claimed in at least one of the preceding claims, characterized in that the beginning of the shifting portion °NW121b / SA with respect to the cam tip NS122b of the first secondary sliding cam amounts to 143° and the beginning of the shifting portion NW121c / SA with respect to the cam tip NS122c of the second secondary sliding cam amounts to 203°.

Images