VALVE TRAIN FOR ACTUATING GAS EXCHANGE VALVES OF AN INTERNAL COMBUSTION ENGINE

Abstract

A valve train for actuating gas exchange valves of an internal combustion engine may include a first camshaft that is received such that it can be rotated in a first shaft axis, and a second camshaft that is received such that it can be rotated in a second shaft axis. At least one of the camshafts may be configured as an adjustable camshaft that comprises an outer shaft in which an inner shaft is received such that it can be rotated. At least one of the camshafts may be drive-connected via a drive means to a crankshaft of the internal combustion engine. A phase shifting member may be provided by way of which the phase position of at least one inner shaft can be changed relative to the phase position of at least one outer shaft of the camshaft. The phase shifting member may comprise an arrangement that is spaced apart from both shaft axes.”

Claims

1.-11. (canceled)

12. A valve train for actuating gas exchange valves of an internal combustion engine, the valve train comprising: a first camshaft received such that the first camshaft is rotatable in a first shaft axis; a second camshaft received such that the second camshaft is rotatable in a second shaft axis, wherein at least one of the first camshaft or the second camshaft is configured as an adjustable camshaft and comprises an outer shaft in which an inner shaft is rotatably received, wherein at least one of the first camshaft or the second camshaft is drive-connected via a drive means to a crankshaft of the internal combustion engine; and a phase shifting member by way of which a phase position of the inner shaft is changeable relative to a phase position of the outer shaft, wherein the phase shifting member includes an arrangement spaced apart from the first and second shaft axes.

13. The valve train of claim 12 wherein the phase shifting member comprises a stator and a rotor, wherein the stator and the rotor are rotatable in a common shifting axis, the common shifting axis being spaced apart from and parallel to the first and second shaft axes.

14. The valve train of claim 13 wherein the phase shifting member is operatively connected via a first transmission means to the inner shaft, wherein the first transmission means is connected to the rotor of the phase shifting motor.

15. The valve train of claim 12 wherein the phase shifting member is operatively connected via a first transmission means to the inner shaft.

16. The valve train of claim 15 wherein the phase shifting member is operatively connected via a second transmission means to the outer shaft of one of the first camshaft or the second camshaft.

17. The valve train of claim 16 wherein the second transmission means is connected to a stator of the phase shifting member.

18. The valve train of claim 16 wherein the phase shifting member comprises a stator and a rotor, wherein the stator and the rotor are rotatable in a common shifting axis, the common shifting axis being spaced apart from and parallel to the first and second shaft axes, wherein the second transmission means is connected to the stator of the phase shifting member.

19. The valve train of claim 18 wherein the second transmission means between the outer shaft of one of the first camshaft or the second camshaft and the phase shifting member is configured as a gearwheel pairing with a first gearwheel and a second gearwheel.

20. The valve train of claim 12 wherein the first camshaft is configured as the adjustable camshaft and comprises the outer shaft in which the inner shaft is rotatably received, wherein the second camshaft is configured as an adjustable camshaft and comprises an outer shaft and an inner shaft, wherein a first transmission means couples the inner shaft of the first camshaft to the inner shaft of the second camshaft such that the phase position of the inner shaft of the first camshaft cannot be changed relative to a phase position of the inner shaft of the second camshaft.

21. The valve train of claim 20 wherein the outer shafts of the first and second camshafts can be driven jointly by the crankshaft of the internal combustion engine by way of the drive means.

22. The valve train of claim 20 wherein the first transmission means between the inner shafts and the phase shifting member is configured as respective gearwheel pairings with a first gearwheel and with a second gearwheel.

23. The valve train of claim 12 wherein the phase shifting member comprises a stator and a rotor, wherein the stator and the rotor are rotatable in a common shifting axis, the common shifting axis being spaced apart from and parallel to the first and second shaft axes, wherein the common shifting axis forms a triangular arrangement with the first and second shaft axes.

Description

PREFERRED EXEMPLARY EMBODIMENT OF THE INVENTION

[0018] Further measures which improve the invention will be shown in greater detail in the following text together with the description of one preferred exemplary embodiment of the invention of the single FIGURE, in which:

[0019] the FIGURE shows a diagrammatic view of a valve train for actuating gas exchange valves of an internal combustion engine having two adjustable camshafts, constructed in accordance with the DOHC principle.

[0020] The figure shows a diagrammatic view of a valve train 1 for actuating gas exchange valves of an internal combustion engine having a first camshaft 10 which is received such that it can be rotated in a first shaft axis 11, and having a second camshaft 20 which is received such that it can be rotated in a second shaft axis 21. The two camshafts 10, 20 can be received jointly in a cylinder head of an internal combustion engine or in a cover module.

[0021] The exemplary embodiment shows the two camshafts 10 and 20 as adjustable camshafts, and the first camshaft 10 comprises an outer shaft 12 and an inner shaft 13, and the inner shaft 13 is mounted rotatably in the outer shaft 12. The second camshaft 20 comprises an outer shaft 22 and an inner shaft 23, the inner shaft 23 likewise being mounted rotatably in the outer shaft 22.

[0022] Fixed cams 14, 24 are attached on the two outer shafts 12, 22, which fixed cams 14, 24 are connected rigidly to the outer shafts 12, 22 so as to rotate with them. Furthermore, adjustable cams 15, 25 are received on the outer side of the outer shafts 12, 22 such that they can be rotated, which adjustable cams 15, 25 are connected fixedly to the inner shafts 13, 23 so as to rotate with them. If the phase position of the inner shafts 13, 23 is rotated with respect to the phase position of the outer shafts 12, 22, the adjustable cams 15, 25 rotate relative to the fixed cams 14, 24 about the shaft axes 11, 21.

[0023] The two outer shafts 12, 22 are driven jointly via a drive means 2, for example a chain or a toothed belt, and a drive wheel 4.1 is attached on the outer shaft 12 of the first adjustable camshaft 10, and a further drive wheel 4.2 is attached on the outer shaft 22 of the second adjustable camshaft 20. Here, the drive means 2 drives both outer shafts 12 and 22 jointly with an identical phase position to one another via the drive wheels 4.1 and 4.2. The drive takes place via a crankshaft 3 which is indicated merely diagrammatically.

[0024] A phase shifting member 30 is arranged between the two camshafts 10 and 20, and the phase shifting member 30 comprises a shifting axis 33 which is arranged spaced apart with respect to the first shaft axis 11 of the first camshaft 10 and with respect to the second shaft axis 21 of the second camshaft 20.

[0025] The phase shifting member 30 is connected via a first transmission means 34 to the inner shafts 13, 23 of the camshafts 10, 20, the outer shaft 22 of the second camshaft 20 being connected via a further, second transmission means 35 to the phase shifting member 30.

[0026] The first transmission means 34 is formed by way of a first gearwheel 34.1 which is connected to a rotor 32 of the phase shifting member 30. Furthermore, the first transmission means 34 comprises two second gearwheels 34.2, and the second gearwheels 34.2 are seated on the respective shaft axes 11 and 21 of the camshafts 10 and 20 and are connected to the inner shafts 13 and 23. The two inner shafts 13, 23 are connected rigidly to one another so as to rotate together by way of the engagement of the two second gearwheels 34.2 on the inner shafts 13, 23 with the first gearwheel 34.1.

[0027] The second transmission means 35 comprises a first gearwheel 35.1 which is connected to the stator 31 of the phase shifting member 30. Furthermore, the second transmission means 35 comprises a second gearwheel 35.2 which is connected to the outer shaft 22 of the second camshaft 20, the connection being shown merely by way of example, and it being possible for the second gearwheel 35.2 of the second transmission means 35 to be connected in an identical way to the outer shaft 12 of the first camshaft 10.

[0028] By way of an activation of the phase shifting member 30, the phase position of the inner shafts 13, 23 of the two camshafts 10, 20 can be changed with respect to the phase position of the outer shafts 12, 22, with the result that the phase position of the respective adjustable cams 15, 25 can be adjusted about the shaft axes 11, 21 relative to the fixed cams 14, 24. As a result, both adjustable camshafts 10, 20 can be adjusted by way of a separately arranged phase shifting member 30.

[0029] The exemplary embodiment shows a coupling of the first transmission means 34 to the rotor 32 of the phase shifter 30, a coupling to the stator 31 also being possible in the same way. Here, in a deviation from the illustration in conjunction with the stator 31, the second transmission means 35 can also be connected to the rotor 32.

[0030] The invention makes an activation of the phase shifting member 30 possible in a particularly simple way, since the accessibility to the phase shifting member 30 is simplified, in particular for fluid routing means. Furthermore, the camshafts 10, 20 comprise merely gearwheels 34.2 and 35.2 which are connected, for example, in one piece to the inner shaft 13, 23 and to the outer shaft 22. As a consequence, the result of the separate construction of the phase shifting member 30 in a divided manner from the camshafts 10, 20 is a simple construction of a valve train, it being possible for the valve train 1 to be of compact configuration, in particular, in the axial direction, that is to say in the structural extent along the shaft axes 11, 21. The limited installation space requirement is produced, in particular, by virtue of the fact that an installation space can be utilized for arranging the phase shifting member 30 which is situated between the two camshafts 10, 20.

[0031] The implementation of the invention is not restricted to the preferred exemplary embodiment which is specified in the above text. Rather, a number of variants are conceivable which use the illustrated solution, even in the case of embodiments of fundamentally different type. All the features and/or advantages which are apparent from the claims, the description or the drawings, including structural details or spatial arrangements, can be essential to the invention both per se and in a very wide variety of combinations.