CAMSHAFT MODULE

Abstract

A camshaft module may include a module body in which at least one camshaft for controlling valves for a charge cycle of an internal combustion engine is accommodated. The camshaft may comprise a support shaft and sliding cam pieces that are accommodated on the support shaft so as to be displaceable in an axial direction of the support shaft. A support element may also be provided on which actuators for the axial displacement of the sliding cam pieces are accommodated. The support element may extend in the axial direction and therefore parallel to the support shaft. In some cases, a coefficient of thermal expansion of the support element substantially corresponds to a coefficient of thermal expansion of the support shaft.

Claims

1.-11. (canceled)

12. A camshaft module comprising: a module body in which a camshaft for controlling valves for a charge cycle of an internal combustion engine is accommodated, the module body having a hood, wherein the camshaft comprises a support shaft and sliding cam pieces that are accommodated on the support shaft so as to be displaceable in an axial direction along the support shaft; and a support element on which actuators for an axial displacement of the sliding cam pieces are accommodated, wherein the support element extends in the axial direction parallel to the support shaft and is disposed below the hood of the module body.

13. The camshaft module of claim 12 wherein a coefficient of thermal expansion of the support element substantially corresponds to a coefficient of thermal expansion of the support shaft.

14. The camshaft module of claim 12 wherein the support element is accommodated in an axially fixed manner on the module body at a connecting point, the camshaft module further comprising an axial bearing for axially supporting the camshaft, wherein the connecting point is disposed on or adjacent to the axial bearing.

15. The camshaft module of claim 14 wherein the module body comprises bearing bridges, wherein at least a part of the axial bearing is disposed on or in one of the bearing bridges, wherein the connecting point comprises a connecting means that connects the support element at least indirectly to the one of the bearing bridges.

16. The camshaft module of claim 12 wherein the support element is accommodated on the module body so as to be guided in an axially-movable manner at a guide point.

17. The camshaft module of claim 12 wherein the support element comprises centering receptacles by way of which the actuators are accommodated in a manner positioned on the support element.

18. The camshaft module of claim 12 wherein at least some of the actuators are assigned to the sliding cam pieces.

19. The camshaft module of claim 12 wherein each of the actuators comprises an actuator pin that is guidable, at least indirectly by way of the support element, relative to the respective sliding cam piece that has been assigned to the actuator.

20. The camshaft module of claim 12 wherein the actuators comprise a housing part and a support part, wherein the support part comprises a centering portion by way of which each actuator is positioned on the support element.

21. The camshaft module of claim 12 wherein the actuators comprise a housing part that is comprised of plastic and with which the actuators are injection molded on the support element by way of injection molding.

22. The camshaft module of claim 12 wherein the support element comprises support parts that are assigned to the actuators, that are fixedly connected to the support element, and that are attachable to the housing parts.

Description

EXEMPLARY EMBODIMENT OF THE INVENTION

[0023] Further measures improving the invention are illustrated in more detail below together with the description of an exemplary embodiment of the invention with reference to the figures, in which:

[0024] FIG. 1 shows a perspective view of a camshaft module of a first embodiment of the module body with a support element, wherein a hood of the module body is illustrated partially sectioned,

[0025] FIG. 2 shows a cross-sectional view of the camshaft module in the region of a camshaft, wherein the sectional plane lies transversely with respect to the axial direction, and wherein the support element is formed within the hood,

[0026] FIG. 3 shows a sectional view of a further embodiment of a camshaft module, and

[0027] FIG. 4 shows a cross-sectional view of the camshaft module in the region of a camshaft, wherein the sectional plane lies transversely with respect to the axial direction, and wherein the support element is formed outside the hood.

[0028] FIG. 1 shows a perspective view of a camshaft module 1 with a module body 10, in which two camshafts 11 for controlling valves for the charge cycle of an internal combustion engine are accommodated. The camshaft module 1 serves in particular for mounting on a cylinder head of the internal combustion engine.

[0029] The module body 10 has a hood 26, and, on the lower side of the hood 26, a plurality of bearing bridges 19 are arranged connected to the latter. The camshafts 11 are accommodated rotatably on the module body 10 by means of the bearing bridges 19. The camshafts 11 each have a support shaft 12, and a plurality of sliding cam pieces 13 are accommodated so as to be movable in an axial direction 14 on each of the support shafts 12. In order to change an axial position of the sliding cam pieces 13, actuators 15 are assigned to the respective sliding cam pieces 13, wherein, for the camshaft module 1 shown, four actuators 15 are provided, of which two actuators are shown.

[0030] The exemplary embodiment shows the feature, which is essential to the invention, of a support element 16 in the form of a sheet-metal element, and the sheet-metal element comprises a steel material which has a coefficient of thermal expansion which is identical or similar to the coefficient of thermal expansion of the support shaft 12. The support element 16 extends here in the same manner as the support shaft 12 of the camshaft 11 in the axial direction 14, and therefore the support element 16 is oriented parallel to the support shaft 12.

[0031] An axial bearing 18 for axially supporting the camshaft 11 is located in an arrangement on the front first bearing bridge 19, and, in conjunction with the axial bearing 18, in particular in the form of a structural unit with the bearing bridge 19, a connecting point 17 is provided, via which the support element 16 is arranged and consequently supported axially on the axial bearing 18 and therefore on the bearing bridge 19. The connecting point 17 is formed by two connecting means 20, illustrated by two screws.

[0032] At the positions of the actuators 15 (not illustrated), the support element 16 comprises centering receptacles 22 into which the actuators 15 are inserted in a positionally precise manner. For this purpose, the actuators 15 comprise a housing part 24, for example made of plastic, and a support part 28, for example made of metal, wherein the support part 28 is inserted with a corresponding centering portion into the respective centering receptacle 22 in a precisely fitting manner. Consequently, the position of the actuators 15 relative to the axial bearing 18 of the camshaft 11 is exactly determined by the support element 16.

[0033] If a change in temperature of the camshaft module 1 takes place, for example when starting up the internal combustion engine, the individual components of the camshaft module 1 expand in a manner induced by the temperature. By means of the thermal expansion, the axial positions of the sliding cam pieces 13 are shifted, and, by means of a coefficient of thermal expansion of the support element 16 accommodating the actuators 15, shifting of the actuators 15 takes place, said shifting being identical in the axial direction 14, starting from the axial bearing 18, to the shifting of the sliding cam pieces 13 because of the thermal expansion of the support shaft 12. The support element 16 is located below the hood 26, which is shown broken open, and the hood 26 is sealed in relation to the outer side with sealing elements via corresponding fastening domes 30 in order to attach the actuators 15 by means of fastening formations 29. By the support element 16 being accommodated on the inside below the hood 26, the support element 16 is washed around with the same oil as the camshaft 11, and therefore the support element 16 substantially takes on the same temperature as the camshaft 11.

[0034] Guide points 21 are provided in order to accommodate the support element 16 on the module body 10 in a manner guided in the axial direction 14. A plurality of guide points 21 guide the support element 16 on the module body 10, and, in the event of thermal expansion, a movement is made possible between the support element 16 and the module body 10, in particular relative to the bearing bridges 19. Only in the connecting point 17 does no movement take place between the bearing bridge 19 and the support element 16, and therefore the guide points 21 are formed, for example, by holding elements which run through elongated holes in the support element 16. Twisting of the support element 16 on the module body 10 is therefore avoided.

[0035] FIG. 2 shows a sectional view through the camshaft module 1 in an intersecting plane to which the axial direction 14 of the camshaft 11 is perpendicular. The section runs through the module body 10 in such a manner that the hood 26 is illustrated sectioned. The support element 16 is shown in a region of a centering receptacle 22, and the centering receptacle 22 forms an annular element into which a centering region 25 is inserted in a precisely fitting manner, wherein the centering region 25 forms a portion of a support part 28 of the actuator 15. The housing 24 of the actuator 15 is located above the support part 28.

[0036] On the lower side of the support part 28, the actuator 15 comprises an actuator pin 23 which is shown retracted into a slotted guide 27 by magnetic lifting. The slotted guide 27 is provided on the outer side in the sliding cam piece 13. The sliding cam piece 13 sits on a support shaft 12 and, together with the latter, forms the camshaft 11.

[0037] The exemplary embodiment shows the support element 16 in the form of a sheet-metal element with an inner region 16a, in which the centering receptacle 22 is accommodated, and edge regions 16b are located laterally with respect to the inner region 16a. As a result, the support element 16 in the form of a sheet-metal element obtains a U shape and is substantially stiffened by the latter.

[0038] Located between the hood 26 and the outer side of the centering receptacle 22 is a first sealing element 31 which permits a certain movability between the centering receptacle 22 and the hood 26 and is therefore oversized. Located on the inside of the centering receptacle 22 is a second sealing element 32 which brings about sealing between the centering region 25 of the metal support part 28 and the centering receptacle 22.

[0039] FIG. 3 shows a further exemplary embodiment of the camshaft module 1 with a module body 10, comprising a hood 26 and a plurality of bearing bridges 19. The support element 16 is fastened to the bearing bridges 19 by the guide points 21 in a manner guided in the axial direction. The guide points 21 are formed by screw-like elements and pass through an elongated hole in the support element 16 in a manner not shown specifically. Consequently, a slight, thermally induced movement of the support element 16 in the axial direction 14 is possible, wherein the connecting points 17 guide the support element 16 over the bearing bridges 19.

[0040] In this exemplary embodiment, the actuators 15 are formed only with the housing part 24 as a housing element made from plastic, and the plastics material of the housing part 24 is injection molded onto the support element 16. In a manner not illustrated specifically, the actuators 15 can therefore be formed without a metallic support part 28, and the actuator pin is particularly advantageously guided directly in the support element 16, as a result of which the axial precision of the actuator pin 23 relative to the sliding cam pieces 13 of the camshaft 11 is further increased.

[0041] The support element 16 is arranged in the outer region on the hood 26 of the module body 10. For sealing the inner region below the hood 26, use is made, for example, of sealing sleeves 33 through which the guide elements which form the guide points 21 are guided. For this purpose, the sealing sleeves 23 comprise, for example, O rings.

[0042] FIG. 4 illustrates a sectional view of the camshaft module 1 in an intersecting plane to which the axial direction 14 of the camshaft 11 is perpendicular, and the hood 26 as part of the module body 10 is illustrated sectioned.

[0043] The exemplary embodiment shows the support element 16 in cross section which, in a delimitation from the exemplary embodiment from FIG. 2, is arranged outside and, in the plane shown, above the hood 26 and therefore takes up the design as per FIG. 3. An actuator 15 is accommodated on the support element 16, said actuator being able to act with an actuator pin 23 on the sliding cam piece 13, which is shown in cross section, of the camshaft 11, in order to displace said sliding cam piece in the axial direction 14 on the support shaft 12, which is likewise shown transversely sectioned. For this purpose, the actuator pin 23 engages in a slotted guide 27 in the sliding cam piece 13.

[0044] The actuator 15 has a housing part 24 which is formed, for example, from plastic and in which a magnetic coil with a magnetic armature can be introduced, the magnetic armature acting directly or indirectly on the actuator pin 23 and initiating a lifting movement therein.

[0045] The exemplary embodiment furthermore shows the actuator 15 with a support part 34 which is part of the support element 16. For example, the support part 34 is formed integrally with the support element 16, or the support part 34 is inserted into a corresponding opening in the support element 16 and is connected to the support element 16 via a joining connection 35, for example is pressed therein or connected thereto in an integrally bonded manner. A particular advantage arises in particular if the centering portion 25 is also formed integrally with the support part 34, and therefore, when the actuator 15 is placed on, the actuator pin 23 is guided directly in a structural component of the support element 16 without joining tolerances accumulating. The actuator as a separable component can therefore be formed without its own support part, and the actuator pin 23 can be guided in the support part 34, which is part of the support element 16, as a result of which highly precisely carrying along of the actuator pin 23 is achieved with a thermal expansion movement of the support element 16.

[0046] In particular, a housing part 24 which is formed from plastic can be screwed or even cast on the support part 34, for example by injection molding the housing part 24 on to the support part 34 in an injection molding process. Located between the hood 26 and the outer side of the centering portion 25 is a sealing element 31 which permits a certain movability between the centering portion 25 and the hood 26.

[0047] The invention is not restricted in its embodiment to the exemplary embodiments indicated above. On the contrary, a number of variants is conceivable which make use of the illustrated solution, even where the embodiments are of a fundamentally different type. All of the features and/or advantages emerging from the claims, the description or the drawings, including design details or spatial arrangements, can be essential to the invention, either individually or in a very wide range of combinations.

LIST REFERENCE SIGNS

[0048] 1 camshaft module [0049] 10 module body [0050] 11 camshaft [0051] 12 support shaft [0052] 13 sliding cam piece [0053] 14 axial direction [0054] 15 actuator [0055] 16 support element [0056] 16a inner region [0057] 16b edge region [0058] 17 connecting point [0059] 18 axial bearing [0060] 19 bearing bridge [0061] 20 connecting means [0062] 21 guide point [0063] 22 centering receptacle [0064] 23 actuator pin [0065] 24 housing part [0066] 25 centering portion [0067] 26 hood [0068] 27 slotted guide [0069] 28 support part [0070] 29 fastening formation [0071] 30 fastening dome [0072] 31 sealing element [0073] 32 sealing element [0074] 33 sealing sleeve [0075] 34 support part [0076] 35 joining connection