METHOD FOR ASSEMBLING A CAMSHAFT IN A MODULE BODY

Abstract

A camshaft may comprise a main shaft, on which at least two sliding cam pieces are accommodated in a rotationally fixed and axially displaceable manner, wherein the sliding cam pieces each comprise a carrier tube, on which are seated cam groups each comprising at least two cam tracks for valve-control purposes, as well as an adjustment element that can be brought into operative connection with an actuator for axial displacement of the two sliding cam pieces. A method for assembling such a camshaft may involve providing a module body with bearing bridges that receive the camshaft in a rotatable manner, inserting a first sliding cam piece into a first bearing bridge, connecting the first sliding cam piece to the adjustment element, inserting a second sliding cam piece into a second bearing bridge, and connecting the second sliding cam piece to the adjustment element with the aid of an axial adjustment distance of at least one of the sliding cam pieces in the bearing bridges.

Claims

1.-10. (canceled)

11. A method for assembling a camshaft that comprises a main shaft on which at least two sliding cam pieces are disposed in a rotationally-fixed and axially-displaceable manner, wherein each of the at least two sliding cam pieces comprises cam groups seated on a carrier tube, wherein each cam group comprises at least two cam tracks for valve-control purposes, the camshaft further comprising an adjustment element that can be brought into operative connection with an actuator for axially displacing the at least two sliding cam pieces, the method comprising: providing a module body that has bearing bridges for receiving the camshaft in a rotatable manner; inserting a first sliding cam piece of the at least two sliding cam pieces into a first bearing bridge of the bearing bridges; connecting the first sliding cam piece to the adjustment element; inserting a second sliding cam piece of the at least two sliding cam pieces into a second bearing bridge of the bearing bridges; and connecting the second sliding cam piece to the adjustment element with aid of an axial adjustment distance of at least one of the first sliding cam piece or the second sliding cam piece in the bearing bridges.

12. The method of claim 11 wherein the carrier tubes of the at least two sliding cam pieces comprise free end portions, wherein the connecting of the first sliding cam piece to the adjustment element is executed by way of the free end portion of the carrier tube of the first sliding cam piece being inserted into a mount in the adjustment element.

13. The method of claim 12 wherein the free end portion of the carrier tube of the first sliding cam piece is inserted into the mount in the adjustment element to form a press-fit arrangement.

14. The method of claim 12 wherein the connecting of the second sliding cam piece to the adjustment element is executed by way of the free end portion of the carrier tube of the second sliding cam piece being inserted into the mount of the adjustment element on a side opposite the free end portion of the carrier tube of the first sliding cam piece.

15. The method of claim 14 wherein the free end portions comprise a surface profiling that is plastically deformed at least in part when the free end portions are inserted into the mount of the adjustment element.

16. The method of claim 11 wherein inserting the first sliding cam piece into the first bearing bridge comprises: positioning a first cam group of the cam groups of the first sliding cam piece on the carrier tube of the first sliding cam piece; introducing the carrier tube of the first sliding cam piece having the first cam group into a closed bearing passage of the first bearing bridge; and positioning a second cam group of the cam groups of the first sliding cam piece on the carrier tube of the first sliding cam piece such that a portion of the carrier tube of the first sliding cam piece that extends through the closed bearing passage of the first bearing bridge is positioned between the first and second cam groups.

17. The method of claim 16 wherein inserting the second sliding cam piece into the second bearing bridge comprises: positioning a first cam group of the cam groups of the second sliding cam piece on the carrier tube of the second sliding cam piece; introducing the carrier tube of the second sliding cam piece having the first cam group into a closed bearing passage of the second bearing bridge; and positioning a second cam group of the cam groups of the second sliding cam piece on the carrier tube of the second sliding cam piece such that a portion of the carrier tube of the second sliding cam piece that extends through the closed bearing passage of the second bearing bridge is positioned between the first and second cam groups of the second sliding cam piece.

18. The method of claim 11 wherein the carrier tubes of the at least two sliding cam pieces comprise free end portions, the method further comprising pushing one of the cam groups from each of the at least two sliding cam pieces, respectively, onto the carrier tubes to pronounced extents such that the free end portion of each carrier tube is formed by a portion of the carrier tube that projects from the cam groups pushed onto the carrier tubes.

19. The method of claim 11 wherein the carrier tubes of the at least two sliding cam pieces comprise free end portions, wherein the connecting of the first sliding cam piece to the adjustment element is executed by way of the free end portion of the carrier tube of the first cam sliding piece being inserted into a mount in the adjustment element, the method further comprising introducing the free end portion of the first sliding cam into the mount in the adjustment element until one of the cam groups of the first sliding cam piece lies laterally against a first side surface of the adjustment element.

20. The method of claim 19 wherein the connecting of the second sliding cam piece to the adjustment element is executed by way of the free end portion of the carrier tube of the second cam sliding piece being inserted into the mount in the adjustment element, the method further comprising introducing the free end portion of the second sliding cam into the mount in the adjustment element until one of the cam groups of the second sliding cam piece lies laterally against a second side surface of the adjustment element that is opposite the first side surface.

21. The method of claim 11 wherein before the first and second sliding cam pieces are connected to the adjustment element, the method further comprises adjusting circumferential positions of the first and second sliding cam pieces relative to a circumferential position of the adjustment element about a center axis of the camshaft that is required for valve-control purposes.

22. The method of claim 11 wherein the carrier tubes of the at least two sliding cam pieces comprise free end portions, the method further comprising guiding the main shaft through the carrier tubes after the free end portions are introduced into a mount in the adjustment element.

23. A camshaft comprising: a main shaft; a first sliding cam piece disposed on the main shaft in a rotationally-fixed and axially-displaceable manner, wherein the first sliding cam piece extends through a first bearing bridge, wherein the first sliding cam piece comprises cam groups seated on a carrier tube, wherein each of the cam groups of the first sliding cam piece comprises at least two cam tracks for valve-control purposes; a second sliding cam piece disposed on the main shaft in a rotationally-fixed and axially-displaceable manner, wherein the second sliding cam piece extends through a second bearing bridge, wherein the second sliding cam piece comprises cam groups seated on a carrier tube, wherein each of the cam groups of the second sliding cam piece comprises at least two cam tracks for valve-control purposes; and an adjustment element that can be brought into operative connection with an actuator for axially displacing the first and second sliding cam pieces, wherein the first and second sliding cam pieces are connected to opposite ends of the adjustment element.

24. The camshaft of claim 23 wherein the first and second sliding cam pieces are connected to the adjustment element by way of end portions of the first and second sliding cam pieces that are disposed within a mount in the adjustment element.

25. The camshaft of claim 24 wherein the end portion of each of the first and second sliding cam pieces is disposed in the mount in the adjustment element in a press-fit manner.

26. The camshaft of claim 24 wherein the end portions comprise a surface profiling that is plastically deformed at least in part due to insertion of the end portions into the mount of the adjustment element.

27. The camshaft of claim 23 wherein the adjustment element is disposed between the first and second bearing bridges.

28. The camshaft of claim 23 wherein the end portions of the first and second sliding cam pieces are positioned between the first and second bearing bridges.

29. The camshaft of claim 23 wherein one of the cam groups of each of the first and second sliding cam pieces abuts the adjustment element.

Description

EXEMPLARY EMBODIMENT OF THE INVENTION

[0019] Further, invention-enhancing measures will be presented in more detail hereinbelow together with the description of a preferred exemplary embodiment of the invention and with reference to the figures, in which:

[0020] FIG. 1 shows a schematic view of a module body which has two bearing bridges, a first carrier tube with a first cam group being inserted into a first bearing bridge,

[0021] FIG. 2 shows the view of the module body with the carrier tube, a first cam group and a second cam group,

[0022] FIG. 3 shows a view of the module body with the first sliding cam piece, on which an adjustment element is arranged,

[0023] FIG. 4 shows the view of the module body with the first sliding cam piece according to FIG. 3, wherein a second carrier tube with a cam group has been inserted in a second bearing bridge in order to form a second sliding cam piece,

[0024] FIG. 5 shows the view of the module body according to FIG. 4, wherein the second sliding cam piece comprises the carrier tube and a first and a second cam group, and

[0025] FIG. 6 shows the camshaft in an arrangement installed in the module body, wherein the two sliding cam pieces are connected to the adjustment element and wherein a main shaft is guided through the sliding cam pieces.

[0026] FIGS. 1 to 6 show the method according to the invention, for installing a camshaft 1 in a module body 16, in various installation steps which can follow one after the other, but the method according to the invention is not necessarily limited to the sequence of method steps presented and, in order for the method for installing a camshaft 1 in a module body 16 to be implemented according to the invention, said method steps can also be carried out in a sequence other than that illustrated.

[0027] FIG. 1 shows, in order to illustrate a first method step, a schematic view of a module body 16, and the module body 16 comprises a first bearing bridge 17A and a second bearing bridge 17B, and the module body 16 can form a module hood or a cylinder head and it is also possible to provide more than two bearing bridges 17A and 17B, which accommodate further sliding cam pieces 11A, 11B on a main shaft 10.

[0028] The bearing bridge 17A has inserted in it a carrier tube 12A, on which a cam group 13A is already fitted. The cam group 13A comprises cam tracks 14 for variable-lift valve control purposes. According to a first variant, in the first instance the carrier tube 12A is introduced into the closed bearing passage 21 of the first bearing bridge 17A, and then the first cam group 13A is pushed onto the carrier tube 12A. According to a second variant, the cam group 13A is already fitted onto the carrier tube 12A outside the module body 16, and then the assembly made up of the carrier tube 12A and the first cam group 13A is guided through the bearing passage 21 of the first bearing bridge 17A.

[0029] The carrier tube 12A comprises a surface profiling 20, onto which is fitted, as illustrated in FIG. 2, a second cam group 13A, which is illustrated on the right, in particular a press-fit arrangement being formed in the process. The surface profiling 20 has, in a manner which is not illustrated specifically, a rolled formation, and groove structures can be made in the passages in the cam groups 13A, this making it possible to establish a press-fit connection which is particularly capable of being subjected to loading. A free piece of the carrier tube 12A here extends between the two cam groups 13A and, via said free piece, the sliding cam piece 11A is accommodated in captive fashion in the bearing bridge 17A and is displaced merely over a displacement distance along the center axis 22.

[0030] FIG. 3 shows a further step of the method according to the invention, in which an adjustment element 15 has been supplied and has been positioned on a free end portion 18A of the carrier tube 12A, as shown in FIG. 2. The free end portion 18A likewise comprises a surface profiling 20, see FIG. 2 in this respect, and this undergoes a slight plastic change in shape when the adjustment element 15 is placed in position.

[0031] A mount 19 in the form of a through-bore is made in the adjustment element 15, and the first end portion 18A of the carrier tube 12A extends some way into the mount 19.

[0032] Proceeding from the finished arrangement of the sliding cam piece 11A in the first bearing bridge 17A, and with the adjustment element 15 attached to the first sliding cam piece 11A, it is the case, as shown in FIG. 4, that the second carrier tube 12B is guided through into the bearing passage 21 of the second bearing bridge 17B, and a cam group 13B is seated, by way of example, on the carrier tube 12B. The second carrier tube 12B likewise has, by way of example, surface profilings 20 for accommodating the further cam group 13B and for forming a structured-surface end portion 18B.

[0033] FIG. 5 shows the second sliding cam piece 11B in the completed state, two cam groups 13B having been positioned on the carrier tube 12B, wherein the bearing bridge 17B for accommodating the sliding cam piece 11B is located between the two cam groups 13B. A further free end portion 18B of the second sliding cam piece 11B is shown, and it is also the case that the second end portion 18B comprises, by way of example, a surface profiling 20, by means of which the second end portion 18B is pressed into the mount 19 of the adjustment element 15 from a side opposite to the first end portion 18A, as is indicated by an arrow.

[0034] As FIG. 6 shows, after the end portion 18B has been inserted into the mount 19 of the adjustment element 15, an assembly made up of two sliding cam pieces 11A and 11B with a joint adjustment element 15 is formed, wherein each of the two sliding cam pieces 11A and 11B are accommodated in a rotatable manner in an associated bearing bridge 17A and 17B. Finally, FIG. 6 also shows a main shaft 10 to complete the camshaft 1 arranged in the module body 16, and, as the illustrated arrow shows, the main shaft 10 is guided through the sliding cam pieces 11A and 11B in the direction of the center axis 22.

[0035] This all results in an advantageous by implementable assembly method for arranging a camshaft 1 in closed bearing bridges 17A and 17B of a module body 16, wherein the sliding cam pieces 11A and 11B each comprise two outer cam groups 13A and 13B, and the bearing passages 21 are located between the two cam groups 13A and 13B with the associated cam tracks 14.

[0036] It is conceivable for the method according to the invention to be implemented to form force-/form-fitting press-fit arrangements by way of a surface profiling 20 on the carrier tube 12A and 12B, wherein the surface profilings 20 both retain the cam groups 13A and 13B on the carrier tubes 12A and 12B in the force-/form-fitting press-fit arrangement and establish the connections between the carrier tubes 12A and 12B and the adjustment element 15 in the force-/form-fitting. This gives rise to connections which can be subjected to high mechanical loading, and there is therefore no need for any further in particular integral joining methods, such as welding or soldering, or connecting elements such as screws or the like.

[0037] The invention is not restricted in its implementation to the exemplary embodiment given above. Rather, a number of variants which make use of the solution presented, even in the case of fundamentally different types of design, are conceivable. All the features and/or advantages which can be gathered from the claims, from the description or from the drawings, including design details or spatial arrangements, may be essential to the invention both in their own right or in a wide variety of different combinations.

LIST OF REFERENCE SIGNS

[0038] 1 Camshaft

[0039] 10 Main shaft

[0040] 11A Sliding cam piece

[0041] 11B Sliding cam piece

[0042] 12A Carrier tube

[0043] 12B Carrier tube

[0044] 13A Cam group

[0045] 13B Cam group

[0046] 14 Cam track

[0047] 15 Adjustment element

[0048] 16 Module body

[0049] 17A Bearing bridge

[0050] 17B Bearing bridge

[0051] 18A End portion

[0052] 18B End portion

[0053] 19 Mount

[0054] 20 Surface profiling

[0055] 21 Bearing passage

[0056] 22 Center axis