METHOD FOR PERMANENTLY FASTENING CAMS ON A CARRIER TUBE

Abstract

A method for permanently fastening a cam on a cam carrier may involve positioning the cam on the cam carrier in a predefined axial and angular position. By way of the positioning, an end face of the cam carrier is aligned with an end face of the cam. The method may also involve positioning a cam segment formed by the cam carrier and the cam in an assembly device. The cam carrier may then be deformed such that the cam is secured at least in a form-fitting or force-fitting manner against movement in an axial direction on the cam carrier. A deformation tool of the assembly device may be advanced in an axial direction onto the end face of the cam carrier, and the cam carrier may be deformed such that material of the cam carrier is forced outward in a radial direction against the cam.

Claims

1.-11. (canceled)

12. A method for permanently fastening a cam on a cam carrier, the method comprising: positioning the cam on the cam carrier in a predefined axial and angular position such that the cam carrier extends through a passage bore of the cam, wherein an end face of the cam carrier is aligned with an end face of the cam; positioning a cam segment formed from the cam carrier and the cam in an assembly device; and deforming the cam carrier such that the cam is secured at least in a form-fitting manner or a force-fitting manner against movement in an axial direction on the cam carrier, wherein a deformation tool of the assembly device is advanced in the axial direction onto the end face of the cam carrier and the cam carrier is deformed such that material of the cam carrier is forced outward in a radial direction against the cam.

13. The method of claim 12 wherein deforming the cam carrier comprises forcing the material of the cam carrier radially outward into a depression of the cam, which depression is formed on the passage bore, provided for placement of the cam onto the cam carrier, of the cam.

14. The method of claim 12 wherein deforming the cam carrier comprises forcing the material of the cam carrier radially outward into a depression of the cam formed on the passage bore.

15. The method of claim 12 wherein deforming the cam carrier comprises forcing the material of the cam carrier radially outward into a depression of the cam formed on the passage bore, the depression being disposed in an encircling manner in the passage bore.

16. The method of claim 12 wherein positioning the cam segment comprises placing the cam segment onto a central peg of the deformation tool of the assembly device.

17. An assembly device for permanently fastening a cam on a cam carrier to produce a cam segment, the assembly device comprising a deformation tool for deforming the cam carrier such that the cam is secured at least in a form-fitting manner or a force-fitting manner against movement in an axial direction on the cam carrier.

18. The assembly device of claim 17 wherein the deformation tool is configured to be advanced in the axial direction onto an end face of the cam carrier to deform the cam carrier such that material of the cam carrier is forced outward in a radial direction against the cam.

19. The assembly device of claim 17 wherein the deformation tool comprises a plurality of deformation elements that are disposed at uniform angular intervals in a circumferential direction.

20. The assembly device of claim 17 wherein the deformation tool comprises a deformation element that extends away from an end face of the deformation tool.

21. The assembly device of claim 20 wherein the deformation element is disposed in an axially-parallel bore of the deformation tool.

22. The assembly device of claim 20 wherein the deformation element is configured as a blade with a tip.

23. The assembly device of claim 22 wherein the tip is wedge-shaped or conical.

24. The assembly device of claim 17 wherein the deformation tool comprises a deformation element that extends axially away from an end face of the deformation tool.

25. The assembly device of claim 24 wherein the deformation element is disposed in an axially-parallel bore of the deformation tool.

26. The assembly device of claim 24 wherein the deformation element is configured as a blade with a tip.

27. The assembly device of claim 26 wherein the tip is wedge-shaped or conical.

Description

[0023] An exemplary embodiment of the present invention will be described in more detail below on the basis of the drawings, in which:

[0024] FIG. 1 shows, in a lateral sectional illustration, an embodiment of an assembly device according to the invention with an arranged embodiment of a cam segment before the axial calking;

[0025] FIG. 2 shows, in a plan view from above, the embodiment of an assembly device according to the invention shown in FIG. 1 with an arranged embodiment of a cam segment, and

[0026] FIG. 3 shows, in a perspective view, the embodiment of an assembly device shown in FIGS. 1 and 2 with an arranged embodiment of a cam segment.

[0027] Features and details with identical function and action are denoted here by the same reference designations in FIGS. 1 to 3.

[0028] FIG. 1 shows, as an example for the realization of the method according to the invention, an embodiment of an assembly device 20 according to the invention. On the assembly device 20, in particular on the deformation tool 10 of the assembly device 20, there has been placed a cam segment 100, as illustrated in FIG. 1 in a longitudinal section along the axis of symmetry. The cam segment 100 comprises an internally toothed cam carrier 1 and cams 2, 3, 4 placed thereon. Here, two of the cams 2, 3, 4 form so-called zero-lift cams, which are denoted by the reference designations 3 and 4. One of the zero-lift cams, which is denoted by the reference designation 4, has been arranged on the cam carrier 1, and pre-mounted for example with an interference fit, such that its axial end face 5 is aligned substantially flush with an axial end face 6 of the cam carrier 1. It is an object of the method according to the invention to securely fasten the cam 4 on the cam carrier 1 at least in an axial direction.

[0029] For this purpose, the deformation tool 10 is arranged coaxially with the above-described workpiece, that is to say the cam segment 100. In the embodiment shown in FIG. 1, the deformation tool 10 comprises an approximately rotationally symmetrical main body 11. Proceeding from an end face 19, which can face toward the cam segment 100, of the deformation tool 10, in particular of the main body 11 thereof, a peg 12 extends coaxially away from the main body 11. The peg 12 advantageously serves for holding and centering the cam segment 100 on the deformation tool 10. Furthermore, in the main body 11, there are arranged a number of deformation elements 13 which are formed for example in the manner of a blade. In the embodiment shown in FIG. 1, a total of three deformation elements 13 are provided. In this exemplary embodiment, the deformation elements 13 comprise a wedge-shaped tip 14, wherein the end edge of the wedge-shaped tip 14 runs in a tangential direction with respect to the workpiece. The deformation elements 13 are inserted in each case into corresponding bores 15 of the deformation tool 10 and are supported there in an axial direction. The fastening of the deformation elements 13 in the main body 11 may be realized in a variety of ways, for example by means of screws 16.

[0030] FIG. 2 illustrates the deformation tool 10 in a view of the end face facing toward the cam segment 100, which in FIG. 1 is situated at the top. The substantially rotationally symmetrical construction of the deformation tool 10 can be seen. In particular, in this embodiment, a number of altogether three deformation elements 13 are provided, which are distributed at equal angular intervals of advantageously 120 in a circumferential direction.

[0031] FIG. 3 shows, in a perspective view, the arrangement from FIGS. 1 and 2, wherein the cam segment 100 is illustrated in transparent form.

[0032] The assembly device 20 advantageously also comprises, in addition to the deformation tool 10, a holding element (not shown here) which serves for holding and positioning the cam segment 100 relative to the deformation tool 10. Said holding element is designed to be movable relative to the deformation tool 10 such that an arrangement of the cam segment 100 on the deformation tool 10 can be made possible. Furthermore, the holding element advantageously makes it possible for the cam element 100 to be supported in an axial direction, such that a corresponding axial force can be imparted to the cam segment 100 by means of the deformation tool 10.

[0033] It is furthermore conceivable for the assembly device 20 to also comprise a drive device (not shown here) for axially moving the deformation tool 10. For this purpose, the deformation tool 10 comprises an attachment region 17 for the attachment of the drive device of the assembly device 20, and an encircling collar 18 for supporting drive forces.

[0034] In the method according to the invention, the following procedure is followed:

[0035] Firstly, the cam carrier 1 is equipped with the cams 2 and the zero-lift cams 3 and 4, and a cam segment 100 is formed. Here, the cams 2, 3, 4 may already be placed with an interference fit onto the cam carrier 1. Here, the cam 4 is aligned such that its end face 5 facing toward the deformation tool 10 is aligned flush in one plane with the corresponding end face 6 of the cam carrier 1. Then, the cam segment 100 is placed in a centered manner onto the peg 12 of the deformation tool 10. Here, the deformation elements 13 lie with their end edges against the end face 6 of the cam carrier 1. Contact with the cam 4 is not provided.

[0036] The end edges of the deformation elements 13 are preferably situated approximately centrally on the ring-shaped end face 6 of the cam carrier 1. The cam carrier 1 is then supported in an axial direction, and a force on the deformation tool 10 is applied in an axial direction to the cam carrier 1. The deformation elements 13 penetrate with their edges into the material of the cam carrier 1 and deform the latter outward in a radial direction, such that the material can for example ingress into a depression 9 formed in the passage bore of the cam 4, such as advantageously a bevel formed on the end face on the cam 4. The cam carrier 1 is thus flared slightly at least in punctiform fashion and secures cam 4, in particular the zero-lift cam 4 shown in FIGS. 1 and 3, against being undesirably pulled off in an axial direction, specifically even in the presence of extreme temperatures such as may be encountered during operation, which could, owing to the different materials of the cam carrier 1 and of the cams 2, 3 and 4, lead to loosening of the interference fit.

[0037] The ingress of the material of the cam carrier 1 into the inner free cross section is advantageously firstly prevented by virtue of the cam carrier 1 comprising, for example, a relatively large bevel on the inner side at the end face, such that even a deformation in the region of the end face 6 does not result in material ingressing into the inner free cross section of the cam carrier 1, because this would possibly impede the displaceability of the cam carrier 1 on the externally toothed base camshaft.

[0038] In the described method step of the calking in an axial direction, the entire deformation tool 10 with the deformation elements 13 supported therein is pressed against the cam segment 100. Provision may also be made for the deformation elements 13 to be arranged movably in the bores 15 of the deformation tool 10 and to be pressed by in each case one dedicated drive device against the cam segment 100. Said drive device may be hydraulic or mechanical.

[0039] The design of the deformation elements 13 may also, in a departure from the wedge-shaped form illustrated, be implemented for example with a curved cutting edge running in a circumferential direction. The deformation elements 13 may ultimately also be conical or pyramid-shaped with a pronounced tip, whereby the deformation forces can be reduced, without jeopardizing the secure hold of the zero-lift cam 4 on the cam carrier 1 after the joining process.