Valve Drive Device

Abstract

A valve drive device, in particular for an internal combustion engine, includes a support element fixed to a housing and at least one axially shiftable cam unit allocated to a valve. The cam unit has at least three cam tracks. At least one switching unit which is a displacement body is provided to displace at least one part of the cam unit in the direction of a first actuation direction for axial shifting. The displacement body displaces at least one part of the cam unit in the direction of a second actuation direction opposing the first actuation direction.

Claims

1.-10. (canceled)

11. A valve drive device, comprising: an axially shiftable cam unit allocated to a valve, wherein the cam unit has at least three cam tracks; and a switching unit, wherein the switching unit includes a displacement body, wherein the cam unit is displaceable in a first actuation direction and in a second actuation direction by the displacement body, and wherein the first actuation direction is opposite the second actuation direction; wherein the displacement body has at least two contact surfaces; wherein the at least two contact surfaces are angled in relation to each other.

12. The valve drive device according to claim 11, wherein the cam unit is allocated to at least two valves.

13. The valve drive device according to claim 11 further comprising a shifting element, wherein the switching unit is adjustable by the shifting element.

14. The valve drive device according to claim 13, wherein the shifting element has at least three shifting positions.

15. The valve drive device according to claim 11, wherein a width of the displacement body is substantially double a width of a cam track of the at least three cam tracks.

16. The valve drive device according to claim 11, wherein the cam unit has at least two displacement contours formed to correspond to the displacement body.

17. The valve drive device according to claim 16, wherein the at least two displacement contours are formed as respective edges of a groove in the cam unit.

18. A method for operating a valve drive device according to claim 11.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 is a schematic depiction of a motor vehicle having a drive unit, which comprises a valve drive device according to the invention, and having a multi-stage transmission in a schematic depiction;

[0017] FIG. 2 is a schematic depiction of the valve drive device according to the invention having a cam unit in a second switching position;

[0018] FIG. 3 is a schematic depiction of the valve drive device according to the invention having the cam unit in an intermediary position from the second switching position into the first switching position;

[0019] FIG. 4 is a schematic depiction of the valve drive device according to the invention having the cam unit in a further intermediary position from the second switching position into the first switching position;

[0020] FIG. 5 is a schematic depiction of the valve drive device according to the invention having the cam unit in a first switching position;

[0021] FIG. 6 is a schematic depiction of the valve drive device according to the invention having the cam unit in an intermediary position from the first switching position into the second switching position;

[0022] FIG. 7 is a schematic depiction of the valve drive device according to the invention having the cam unit in a further intermediary position from the first switching position into the second switching position;

[0023] FIG. 8 is a schematic position of the valve drive device according to the invention having the cam unit in the second switching position;

[0024] FIG. 9 is a schematic depiction of the valve drive device according to the invention having a cam unit in an intermediary position from the second switching device into the third switching position;

[0025] FIG. 10 is a schematic depiction of the valve drive device according to the invention having a cam unit in a further intermediary position from the second switching position into the third switching position; and

[0026] FIG. 11 is a schematic depiction of the valve drive device according to the invention having a cam unit in a third switching position.

DETAILED DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 schematically shows a motor vehicle 25. The motor vehicle 25 comprises a drive train, by means of which drive wheels 26 of the motor vehicle 25 are driven, which is not visible in further detail. The drive train comprises an internal combustion engine 11. The internal combustion engine 11 is formed from a combustion motor. Furthermore, the motor vehicle 25 has a multi-stage transmission 27. The internal combustion engine 11 has a driven crankshaft which is connected to a transmission input element of the multi-stage transmission 27. The multi-stage transmission 27 is formed from a motor vehicle transmission. The multi-stage transmission 27 forms a part of the drive train of the motor vehicle 25. The internal combustion engine 11 comprises at least one valve drive device 10. Preferably, the internal combustion engine 11 comprises several valve drive devices 10. The internal combustion engine 11 is formed as a motor vehicle internal combustion engine, which is provided to convert chemical energy into kinetic energy which serves, in particular, to propel a motor vehicle 25. The internal combustion engine 11 here has several cylinders each having several valves 28, 29. The internal combustion engine 11 has two valves 28, 29 formed as inlet valves and two valves formed as outlet valves. In principle, it is also conceivable that the internal combustion engine 11 has a different number of valves 28, 29. Here, the valves 28, 29 are schematically depicted by their actuation plane in FIGS. 2 to 10.

[0028] FIGS. 2 to 11 show a schematic depiction of the valve drive device 10 in various switching positions. The valve drive device 10 is part of the internal combustion engine 11. The valve drive device 10 is provided for actuating the valves 28, 29 of the internal combustion engine 11. The valve drive device 10 has a cam shaft 30 for actuating the valves 28, 29. In FIGS. 2 to 11, only one part of the cam shaft 30, which is allocated to a cylinder, is depicted. The cam shaft 30 is mounted in a support element 12 fixed to the housing. The valve drive device 10 has the support element 12 fixed to the housing. Here, it is conceivable that the support element 12 is formed as a housing of the valve drive device 10. Furthermore, the valve drive device 10 has a further cam shaft not depicted in more detail. The depicted cam shaft 30 is here exemplarily formed as an inlet cam shaft and the cam shaft not depicted in more detail as an outlet cam shaft. Below, only the part of the cam shaft 30 shown in FIGS. 2 to 11 is described in more detail. The description can also be transferred to the part of the cam shaft 30 not depicted in more detail and the cam shaft that is not depicted in more detail.

[0029] The cam shaft 30 is rotatably mounted in a valve drive housing that is not depicted in more detail. Here, the cam shaft 30 is mounted rotatably around an axis of rotation 31. Here, the axis of rotation 31 of the cam shaft 30 is aligned substantially in parallel to an axis of rotation of a crank shaft of the internal combustion engine 11. The cam shaft 30 is driven by the crank shaft via a coupling not depicted in more detail. The valve drive device 10 comprises one cam unit 13 per cylinder. The valve drive device 10 has a cam unit 13 that is axially shiftable and allocated to at least one valve 28, 29. The valve unit 13 is allocated to two valves 28, 29. In principle, it is also conceivable that the valve drive device 10 has a different number of cam units 13 per cylinder. The cam unit 13 is formed from a cam element. In principle, it is also conceivable that the cam unit 13 is formed from several cam elements.

[0030] The cam unit 13 is arranged axially shiftably on the cam shaft 30. Here, the cam unit 13 is rotationally fixedly coupled to the cam shaft 30. Here, the cam unit 13 is connected to the cam shaft 30, in particular via a toothing that is not depicted in more detail. The cam unit 13 is provided for actuating the valves 28. 29. The cam unit 13 has at least three cam tracks 14, 15, 16, 14, 15, 16. The cam unit 13 has three cam tracks 14, 15, 16, 14, 15, 16 per valve 28, 29. In principle, it is also conceivable that the cam unit 13 has only two or more than the three cam tracks 14, 15, 16, 14, 15, 16 per valve 28. 29. The cam tracks 14, 15, 16, 14, 15, 16 each have different contours and thus actuate the respective valve 28, 29 with correspondingly different valve strokes. In a first switching position of the cam unit 13, the first cam tracks 14, 14 actuate the respective valve 28, 29. In a first switching position of the cam unit 13, the first cam tracks 14, 14 actuate the respective valve 28, 29 with an average stroke. In a second switching position of the cam unit 13, the second cam tracks 15, 15 actuate the respective valve 28, 29. In a second switching position of the cam unit 13, the second cam tracks 15, 15 actuate the respective valve 28, 29 with a large stroke. In a third switching position of the cam unit 13, the third cam tracks 16, 16 actuate the respective valve 28, 29. In a third switching position of the cam unit 13, the third cam tracks 16, 16 actuate the respective valve 28, 29 with a low stroke. The actuation of a valve 28, 29 by a cam track 14, 15, 16, 14, 15, 16 takes place in a manner known to the person skilled in the art.

[0031] Furthermore, the valve drive device 10 has a switching unit 17. The switching unit 17 is provided for axially shifting at least one part of the cam unit 13. The switching unit 17 is provided for axially shifting the cam unit 13 on the cam shaft 30. The valve drive device 10 has the switching unit 17 for adjusting the cam unit 13 on the cam shaft 30 between the three switching positions. The switching unit 17 is provided to axially shift the cam unit 13 on the cam shaft 30 in order to bring the different cam tracks 14, 15, 16, 14, 15, 16 into engagement with the respective valve 28, 29. Here, the switching unit 17 is provided to adjust the cam unit 13 by means of a displacer principle between the switching positions. The switching unit 17 is provided to adjust the cam unit 13 by a displacement, in particular orthogonally to an actuation direction 32 of the switching unit 17.

[0032] The switching unit 17 comprises a displacement body 18. The displacement body 18 is provided to displace at least one part of the cam unit 13 in the direction of a first actuation direction 32 for axial shifting. The displacement body 18 is provided to displace the cam unit 13 in the direction of the first actuation direction 32 for axial shifting. Furthermore, the displacement body 18 is provided to displace the cam unit 13 in the direction of a second actuation direction 33 opposite the first actuation direction 32. The actuation directions 32, 33 each extend in parallel to the axis of rotation 31 of the cam shaft 30. For the axial shifting of the cam unit 13, the displacement body 18 is provided to be operatively introduced between the support element 12 and the cam unit 13. The displacement body 18 has at least one width b1, which corresponds to a shifting path of the cam unit 13 between two switching positions of immediately adjacent cam tracks 14, 15, 16, 14, 15, 16. The width of the displacement body 18 corresponds to at least one width b2 of a cam track 14, 15, 16, 14, 15, 16. A width b1 of the displacement body 18 is substantially double the width b2 of a cam track 14, 15, 16, 14, 15, 16.

[0033] The cam unit 13 forms at least one displacement contour 22, 23 which is formed to corresponding to the displacement body 18. The cam unit 13 has two displacement contours 22, 23 formed to correspond to the displacement body 18. The displacement contours 22, 23 are provided so that the displacement body 19 comes into frictional contact for adjusting the cam unit 13. The displacement contours 22, 23 are here each allocated to one of the actuation directions 32, 33. The first displacement contour 22 is contacted by the displacement body 18 for displacing the cam unit 13 in the first actuation direction 32. The second displacement contour 23 is contacted by the displacement body 18 for displacing the cam unit 13 in the second actuation direction 33. The two displacement contours 22, 23 are each formed as an edge of a groove 24 in the cam unit 13. Here, the peripheral groove 24 has a width which approximately corresponds to the width b1 of the displacement body 18.

[0034] Furthermore, the displacement body 18 has at least two different contact surfaces 19, 20. The displacement body 18 has two angled contact surfaces 19, 20. The two contact surfaces 19, 20 of the displacement body 18 are angled in relation to each other. The two contact surfaces 19, 20 are each allocated to a displacement contour 22, 23. The first contact surface 19 is provided for a contacting of the first displacement contour 22. The second contact surface 20 is provided for a contacting of the second displacement contour 23. In the event of an operative insertion of the displacement body 18, firstly one of the angled contact surfaces 19, 20 of the displacement body 18 touches the cam unit 13. Here, the first contact surface 19 is used for a displacement of the cam unit 13 in the first actuation direction 32, while the second contact surface 20 is used for a displacement of the cam unit 13 in the second actuation direction 33. The displacement body 18 has a wedge shape, which forms the angled contact surfaces 19, 20. In the event of the displacement body 18 being inserted in the radial direction in relation to the axis of rotation 31 onto the cam unit 13, one of the contact surfaces 19, 20 laterally engages on the respectively corresponding displacement contour 22, 23 of the cam unit 13. In the event of another insertion of the displacement body 18, the cam unit 13 slides on the respective contact surface 19, 20 depending on the actuation direction 32, 33 and is shifted by the displacement body 18 in the respective actuation direction 32, 33. In a switching process, the displacement body 18 is pressed against the respectively corresponding displacement contour 22, 23 of the cam unit with one of its angled contact surfaces 19, 20 depending on the actuation direction 32, 33 and it thus displaces the cam unit 13 in a corresponding actuation direction 32, 33.

[0035] In an operating state, in which the cam unit 13 is not axially shifted between its switching positions, the displacement contour 18 forms an axial mount for the cam unit 13. With the formation of the axial mount for the cam unit 13, the displacement body 18 respectively forms axial stops for the cam unit 13, by the displacement body 18 being arranged in the groove 24 of the cam unit 13. In principle, it is also conceivable that the displacement body 18 and the corresponding displacement contours 22, 23 are formed in a different manner seeming significant to the person skilled in the art. Here, it is conceivable, for example, that the displacement contours 22, 23 are formed as ribs with an angled contact surface. Here, the displacement body 18 could be formed correspondingly equivalently.

[0036] The switching unit 17 comprises an actuator 34. The actuator 34 is provided for actuating the displacement body 18. Furthermore, the switching unit 17 comprises a housing 35. Here, the actuator 34 of the switching unit 17 is arranged inside the housing 35. The displacement body 18 is shiftably mounted in the housing 35. Here, the displacement body 18 is linearly shiftable in a radial direction in relation to the axis of rotation 31. In a state in which the displacement body 19 is operatively introduced into the cam unit 13, the displacement body 19 is in an extended state. In a first switching position of the actuator 34, the displacement body 18 engages in the grove 24 of the cam unit 13. In a second switching position, the displacement body 18 is spaced apart from the cam unit 13.

[0037] Furthermore, the valve drive device 10 has a shifting element 21. The shifting element 21 is provided to adjust the switching unit 17 axially in relation to the support element 12. The shifting element 21 is provided to adjust the entire switching unit 17 in parallel to the axis of rotation 31 of the cam shaft 30. To that end, the switching unit 17 is mounted axially shiftably in the housing in the valve drive device 10. Here, the switching unit 17 is mounted in the housing of the valve drive device 10 via a mounting unit not depicted in more detail. Here, the switching unit 17 is mounted shiftably between at least two switching positions. The shifting element 21 has three shifting positions. The switching unit 17 is thus mounted shiftably between three switching positions. In FIGS. 2, 3, 7, 8, and 9, a first switching position of the switching unit 17 is depicted. In FIGS. 4, 5 and 6, a second switching position of the switching unit 17 is depicted. In FIGS. 10 and 11, a third switching position of the switching unit 17 is depicted. The switching unit 17 is provided to be axially shifted for switching to an outer cam track 14, 14, 16, 16 of the three cam tracks 14, 15, 16, 14, 15, 16. The shifting element 21 is formed as an actuator which comprises an axially extendable actuating lever. Here, the actuator is formed as an electronically controllable spindle gear. In principle, it is also conceivable that the actuator is formed as a pneumatic or hydraulic actuator.

[0038] In FIGS. 2 to 11, the valve drive device 10 is respectively shown in different states of a method for the operation of the valve drive device 10. FIG. 2 shows the valve drive device 10 in a second switching position. The displacement body 18 is here in engagement with the groove 24 of the cam unit 13. The valves 28, 29 are supplied with a large stroke. To prepare a switching of the valve drive device 10 from the second switching position into the first switching position, the displacement body 18 is radially moved away from the cam unit 13 by means of the actuator 34 (FIG. 3). Then, to switch the valve drive device 10 from the second switching position into the first switching position, the switching unit 17 is shifted by means of the shifting element 21. The switching unit 17 is shifted into the second switching position (FIG. 4). Following this, the displacement body 18 is moved radially towards the cam unit 13 by means of the actuator 34, such that the cam unit 13 is displaced in the second actuation direction 33 by means of the second contact surface 20. The valve drive device 10 is now in a first switching position (FIG. 5). To prepare a switching of the valve drive device 10 from the first switching position back into the second switching position, the displacement body 18 is radially moved away from the cam unit 13 by means of the actuator 34. Then, to switch the valve drive device 10 from the first switching position into the second switching position, the switching unit 17 is shifted by means of the shifting element 21. The switching unit 17 is shifted into the first switching position (FIG. 7). Following this, the displacement body 19 is radially moved towards the cam unit 13 by means of the actuator 34, such that the cam unit 13 is displaced in the first actuation direction 32 by means of the first contact surface 19. The valve drive device 10 is now back in a second switching position (FIG. 8). To prepare a switching of the valve drive device 10 from the second switching position into the third switching position, the displacement body 18 is radially moved away from the cam unit 13 by means of the actuator 34. Then, to switch the valve drive device 10 from the second switching position into the third switching position, the switching unit 17 is shifted by means of the shifting element 21. The switching unit 17 is shifted into the third switching position (FIG. 10). Following this, the displacement body 19 is radially moved towards the cam unit 13 by means of the actuator 34, such that the cam unit 13 is displaced in the first actuation direction 32 by means of the first contact surface 19. The valve drive device 10 is now in a third switching position (FIG. 11). To prepare a switching of the valve drive device 10 from the third switching position back into the second switching position, the displacement body 19 is radially moved away from the cam unit 13 by means of the actuator 34. Then, to switch the valve drive device 10 from the third switching position back into the second switching position, the switching position 17 is shifted by means of the shifting element 21. The switching unit 17 is shifted into the first switching position. Following this, the displacement body 18 is radially moved towards the cam unit 13 by means of the actuator 34, such that the cam unit 13 is displaced in the second actuation direction 33 by means of the second contact surface 20. The valve drive device 10 is now back in a second switching position (FIGS. 2 and 8).

LIST OF REFERENCE CHARACTERS

[0039] 10 Valve drive device [0040] 11 Internal combustion engine [0041] 12 Support element [0042] 13 Cam unit [0043] 14 Cam tracks [0044] 15 Cam tracks [0045] 16 Cam tracks [0046] 17 Switching unit [0047] 18 Displacement body [0048] 19 Contact surface [0049] 20 Contact surface [0050] 21 Shifting element [0051] 22 Displacement contour [0052] 23 Displacement contour [0053] 24 Groove [0054] 25 Motor vehicle [0055] 26 Drive wheel [0056] 27 Multistage gear [0057] 28 Valve [0058] 29 Valve [0059] 30 Cam shaft [0060] 31 Axis of rotation [0061] 32 Actuation direction [0062] 33 Actuation direction [0063] 34 Actuator [0064] 35 Housing [0065] b1 Width [0066] b2 Width