Abstract
A camshaft may include a support shaft and a component with a passage opening that receives the support shaft. The support shaft may include fastening regions and positioning regions alternating in an axial direction. A diameter of the support shaft in the fastening regions may be greater than a diameter of the support shaft in the positioning regions. Furthermore, the passage opening of the component may include axially spaced fastening sections with positioning sections arranged between pairs of the fastening sections. A diameter of the passage opening in the fastening sections may be smaller than a diameter of the passage opening in the positioning sections. Further, the diameter of the support shaft in the positioning regions may be smaller than the diameter of the passage opening in the fastening sections, and the diameter of the support shaft in the fastening regions may be smaller than the diameter of the passage opening in the positioning sections.
Claims
1.-14. (canceled)
15. A camshaft comprising: a support shaft that comprises fastening regions and positioning regions that alternate along an axis of the support shaft; and a component with a passage opening for receiving the support shaft, wherein the passage opening comprises fastening sections that are axially spaced apart and positioning sections that are disposed between pairs of the fastening sections, wherein a diameter of the support shaft in the positioning regions is smaller than a diameter of the passage opening in the fastening sections, wherein a diameter of the support shaft in the fastening regions is smaller than a diameter of the passage opening in the positioning sections, wherein the diameter of the support shaft in the fastening regions is greater than the diameter of the support shaft in the positioning regions, wherein the diameter of the passage opening in the fastening sections is smaller than the diameter of the passage opening in the positioning sections, wherein axial extents of the fastening regions, the positioning regions, the fastening sections, and the positioning sections are such that there is a first axial position of the component relative to the support shaft in which all of the fastening sections of the component fall within the positioning regions of the support shaft and all of the positioning sections of the component overlap with the fastening regions of the support shaft in an axial direction.
16. The camshaft of claim 15 wherein the axial extents of the fastening regions, the positioning regions, the fastening sections, and the positioning sections are such that there is a second axial position of the component relative to the support shaft in which the fastening sections at least partly overlap the fastening regions in the axial direction to fix the component on the support shaft.
17. The camshaft of claim 15 wherein the axial extents of all of the fastening regions are the same, wherein the axial extents of all of the positioning regions are the same.
18. The camshaft of claim 15 wherein the axial extents of all of the fastening sections are the same, wherein the axial extents of all of the positioning sections are the same.
19. The camshaft of claim 15 wherein all positioning regions, fastening regions, positioning sections, and fastening sections each have the same axial extent and a sum of the axial extents of the positioning regions and the fastening regions is equal to a sum of the axial extents of the positioning sections and the fastening sections.
20. The camshaft of claim 15 wherein the fastening regions have a first axial extent, the positioning regions have a second axial extent, the fastening sections have a third axial extent, and the positioning sections have a fourth axial extent, wherein the first axial extent is smaller than the fourth axial extent and the third axial extent is smaller than the second axial extent.
21. The camshaft of claim 15 wherein the positioning regions comprise introduction chamfers.
22. A method for assembling a camshaft comprising: providing a support shaft that includes fastening regions and positioning regions that alternate along an axis of the support shaft; providing a component with a passage opening for receiving the support shaft, wherein the passage opening comprises fastening sections that are axially spaced apart and positioning sections that are disposed between pairs of the fastening sections, wherein a diameter of the support shaft in the positioning regions is smaller than a diameter of the passage opening in the fastening sections, a diameter of the support shaft in the fastening regions is smaller than a diameter of the passage opening in the positioning sections, the diameter of the support shaft in the fastening regions is greater than the diameter of the support shaft in the positioning regions, the diameter of the passage opening in the fastening sections is smaller than the diameter of the passage opening in the positioning sections, axial extents of the fastening regions, the positioning regions, the fastening sections, and the positioning sections are such that there is a first axial position of the component relative to the support shaft in which all of the fastening sections of the component fall within the positioning regions of the support shaft and all of the positioning sections of the component overlap with the fastening regions of the support shaft in an axial direction, the axial extents of the fastening regions, the positioning regions, the fastening sections, and the positioning sections are such that there is a second axial position of the component relative to the support shaft in which the fastening sections at least partly overlap the fastening regions in the axial direction to fix the component on the support shaft; and at least one of cooling the support shaft or heating the component so that the support shaft and the fastening regions of the support shaft can be pushed through the passage opening.
23. The method of claim 22 further comprising: pushing the support shaft through the passage opening so that the component assumes the first axial position; at least one of heating the support shaft or cooling the component; adjusting an angular position of the component relative to the support shaft while the component is located in the first axial position; and pressing the component into the second axial position.
24. A method for assembling a module for a motor vehicle engine from at least one cylinder head cover with bearing mounts for the support shaft and the component of claim 23, wherein the camshaft comprising the support shaft and the component is built according to the method of claim 23, wherein the support shaft is pushed simultaneously through the passage opening and through the bearing mounts of the cylinder head cover.
25. The method of claim 22 further comprising: pushing the support shaft through the passage opening so that the component assumes a preliminary position in which the fastening sections partly overlap the fastening regions in the axial direction; at least one of heating the support shaft or cooling the component, as a result of which the component is detachably fixed in the preliminary position; detaching the component from the preliminary position and bringing the component into the first axial position; adjusting an angular position of the component relative to the support shaft while the component is located in the first axial position; and pressing the component into the second axial position.
26. A method for assembling a module for a motor vehicle engine from at least one cylinder head cover with bearing mounts for the support shaft and the component of claim 25, wherein the camshaft comprising the support shaft and the component is built according to the method of claim 25, wherein the support shaft is pushed simultaneously through the passage opening and through the bearing mounts of the cylinder head cover.
27. A camshaft comprising: a support shaft having a first diameter profile in an axial direction; and a component with a passage opening for receiving the support shaft, wherein the passage opening has a second diameter profile in the axial direction, wherein in a first axial position of the component the first diameter profile and the second diameter profile correspond to one another such that the support shaft and the component engage into one another so that the component is fixed in the axial direction in a form-fit manner.
28. The camshaft of claim 27 wherein the first diameter profile and the second diameter profile correspond to one another such that the component in the first axial position is freely rotatable relative to the support shaft.
29. The camshaft of claim 27 wherein in a second axial position of the component the component is fixed in a force-fit manner, wherein the first and second diameter profiles are configured such that the component is movable from the first axial position to the second axial position only through a plastic deformation of at least one of the first diameter profile or the second diameter profile.
30. The camshaft of claim 29 wherein the second axial position differs from the first axial position of the component by less than an axial width of the component.
Description
[0054] In the following, the invention is explained in more detail by way of schematic drawings representing the principle of the invention. In detail:
[0055] FIG. 1 shows a component in the form of a cam with fastening sections and a positioning section;
[0056] FIG. 2 shows a detail enlargement of a support shaft with fastening regions and positioning regions;
[0057] FIG. 3 shows a cam on a support shaft in a first axial position;
[0058] FIG. 4 shows a cam on a support shaft in a second axial position;
[0059] FIG. 5 shows a further developed design of a component according to the invention;
[0060] FIG. 6 shows a cam on a support shaft in a preliminary position;
[0061] FIG. 7 shows an extract of a module for a motor vehicle engine with a cam on a support shaft in a first axial position;
[0062] FIG. 8 shows an extract of a module for a motor vehicle engine with a cam on a support shaft in a second axial position.
[0063] In FIG. 1, a component 1 with a passage opening 3 is shown in two sections. The component is a cam with a cam tip 2 and a cam base circle 4. The passage opening 3 in this case comprises two fastening sections 5a and 5b which are axially spaced from one another. Here, the axial direction is predetermined by the axis of rotation of the camshaft later on. Between the two axially adjacent fastening sections 5a and 5b a positioning section 7a is arranged. In the two fastening sections 5a and 5b the passage opening 3 has a diameter DBA. In the positioning section 7a located in between, the diameter DPA of the passage opening 3 is enlarged. Thus, DPA>DBA applies. Both in the positioning section 7a and also in the two fastening sections 5a and 5b the passage opening 3 has a cylindrical shape. Alternatively it is also possible that the fastening regions 5a and 5b are formed by separate mouldings which are distributed over the circumference of the passage opening. This is the case for example when an internal toothing is arranged in the fastening regions 5a and 5b. In these cases, the diameter DBA in the fastening regions is to be understood as the minimum circle diameter. In the case of an internal toothing, the diameter DBA thus corresponds to the spacing of the tooth tips located opposite.
[0064] By way of FIG. 1 it is likewise evident that the fastening regions have a first axial extent 23 and the positioning regions a second axial extent 25.
[0065] FIG. 2 shows an extract from a support shaft 9. Here, the support shaft 9 comprises two fastening regions 11a and 11b as well as two positioning regions 13a and 13b. In axial direction, the fastening regions 11a, 11b and the positioning regions 13a, 13b alternate in each case. While the diameter of the support shaft 3 in the positioning regions 13a and 13b corresponds to a base diameter of the support shaft 3, the diameter in the fastening regions 11a and 11b is expanded. This expansion can for example be produced, as schematically shown in FIG. 2, by way of rolling. Alternatively, the support shaft, starting out from a larger diameter, can also be suitably ground off. Accordingly, the diameter DBB of the support shaft 9 in the fastening regions 11a, 11b is greater than the diameter DPB of the support shaft 9 in the positioning regions 13a, 13b.
[0066] It is evident, furthermore, by FIG. 2, that the fastening sections have a third axial extent 27 and the positioning sections a fourth axial extent 29.
[0067] FIG. 3 shows the component 1 relative to the support shaft 9. It is thus evident that the diameter DPB of the support shaft 9 in the positioning regions 13a, 13b is smaller than the diameter DBA of the passage opening in the fastening sections 5a, 5b. It becomes clear, furthermore, that the diameter DBB of the support shaft in the fastening regions 11a and 11b is smaller than the diameter DPA of the passage opening in the positioning section 7a. In the shown representation, the component 1 is located in a first axial position relative to the support shaft 9. The axial extent of the fastening regions 11a and 11b, of the positioning regions 13a and 13b, of the fastening sections 5a and 5b and of the positioning section 7a is such that in the shown first axial position of the component 1 the fastening section 5a falls completely within the positioning region 13a. Furthermore, the fastening section 5b falls completely within the positioning region 13b. In addition, the positioning section 7a overlaps the fastening region 11a. The special selection of axial extents and diameter relations results in that the support shaft 9 and the component 1 engage into one another in the manner of intermeshing teeth. The component 1 in the first axial position is freely rotatable relative to the support shaft 9 so that an angular position of the component 1 can be adjusted.
[0068] By way of the relation of component 1 relative to the support shaft 9 shown in FIG. 3 it becomes clear that the first axial extent 23 is smaller than the fourth axial extent 29 and the third axial extent 27 is smaller than the second axial extent 25. The shown embodiment is the simplest regular version with exactly two fastening regions and two fastening sections.
[0069] The configuration shown in FIG. 3, in which the component 1 assumes the first axial position, is produced in that initially the support shaft 9 is cooled and/or the component 1 is heated. Because of the temperature differential, different thermal deformations occur so that the support shaft 9 with its fastening regions 11a and 11b can be pushed through the passage opening 3 of the component 1. In this state, the diameter of the fastening sections 5a and 5b is thus greater than the diameter of the fastening regions 11a and 11b. As soon as the first axial position of the component 1 has been adjusted, a temperature equalization is carried out during which the support shaft 9 is heated and/or the component 1 cooled, so that the diameter of the support shaft 9 in the fastening regions 11a, 11b is greater than the diameter of the passage opening 3 of the component 1 in the fastening sections 5a, 5b.
[0070] Starting out from the first axial position of the component 1, which is shown in FIG. 3, the component 1 is pressed on into a second axial position. The second axial position is shown in FIG. 4. During the pressing-on into the second axial position, the fastening regions 11a and 11b are plastically deformed so that the component 1 is connected with the support shaft 9 in a force-fit manner. In order to achieve this, the axial extent of the fastening regions 11a and 11b, of the positioning regions 13a and 13b, of the fastening sections 5a and 5b and of the positioning section 7a is such that in the second axial position the fastening regions 11a and 11b at least partially overlap the fastening sections 5a and 5b. While establishing this overlap the described plastic deformation occurs which fixes the component 1 on the support shaft 9 in a force-fit manner.
[0071] FIG. 5 shows a further developed version of the component 1. In this embodiment, the component 1 comprises introduction chamfers 15 in the edge regions of the positioning regions 5a and 5b. In the region of the introduction chamfers 15, the passage opening 3 has a funnel-like profile between a greater and a smaller diameter. This brings about a controlled pressing-on operation from the first into the second axial position.
[0072] FIG. 6 shows the component 1, which assumes a preliminary position, in which the fastening sections 5a and 5b in axial direction partly overlap the fastening regions 11a and 11b. This configuration is established in that initially the support shaft 9 is cooled and/or the component 1 heated. Because of the temperature differential different thermal deformations occur so that the support shaft 9 with its fastening regions 11a and 11b can be pushed through the passage opening 3. In this state, the diameter of the fastening sections 5a and 5b is thus greater than the diameter of the fastening regions 11a and 11b. As soon as the preliminary position of the component 1 has been adjusted, a temperature equalization is carried out during which the support shaft 9 is heated and/or the component 1 cooled, so that the diameter of the support shaft 9 in the fastening regions is smaller than the diameter of the component 1 in the fastening sections. In contrast with the configuration shown in FIG. 3, this additional intermediate step has the advantage that the component 1 following the temperature equalization is not immediately freely moveable. Instead, the component 1 is detachably fixed on the preliminary position in a defined angular orientation. Thus, the support shaft 1 can be moved together with the component 1 without the angular position of the component 1 changing in an uncontrolled manner. Starting out from this intermediate step the component 1 is detached from the preliminary position and brought into the first axial position. In this position, the angular position of the component 1 relative to the support shaft is adjusted and the component pressed on into the second axial position.
[0073] FIG. 6 shows the component 1 with introduction chamfers 15. However, this is not compulsory for the assembly version with preliminary position. The component 1 shown in FIG. 1 without introduction chamfer can also be suitably preliminarily positioned.
[0074] FIG. 7 shows an extract of a module 21 for a motor vehicle engine. The module 21 comprises a cylinder head cover 17 with bearing mounts 19 for a support shaft 9. The advantage of the invention becomes particularly clear from FIG. 7. With known assembly methods, such as for example shown in WO2012/031770, the components are initially positioned next to the expansions of the support shaft and pressed onto the expansions in a following step. This means that the component during the pressing-in operation in axial direction has to be moved by at least a distance in axial direction which corresponds to the axial width of the component. As shown here in FIG. 7 there are applications however in the case of which such an assembly is not possible since the axial installation space is not sufficient in order to position the component next to the expansion. Here, the axial distance 31 of the two bearing mounts 19 for example is smaller than twice the axial width 33 of the component 1, so that the component 1 cannot be positioned next to the fastening regions 11a, 11b, 11c, 11d. Instead, support shaft 9 and component 1 are configured in such a manner that there is a first axial position of the component 1 relative to the support shaft 9 on which the component 1 is freely rotatable, but which is not located entirely next to the fastening regions 11a, 11b, 11c and 11d. For this reason, the component 1, during the pressing-on, has to be moved in axial direction by a significantly shorter distance so that the assembly becomes possible also in applications with little axial installation space. The special configuration in the shown embodiments consists in that the support shaft 9 in each case comprises four fastening regions 11a, 11b, 11c, 11d and positioning regions 13a, 13b, 13c, 13d which are each axially alternately arranged. Furthermore, the passage opening comprises four axially spaced fastening sections 5a, 5b, 5c, 5d, between which a positioning section 7a, 7b, 7c is arranged in each case. Analogous to FIGS. 1 and 2, the diameter DPB of the support shaft 9 in the positioning regions 13a-d is smaller than the diameter DBA of the passage opening 3 in the fastening sections 5a-d. In addition, the diameter DBB of the support shaft 9 in the fastening regions 11a-d is smaller than the diameter DPA of the passage opening 3 in the positioning sections 7a, 7b, 7c. Next to the diameter relations, the fastening regions 11a-d, the positioning regions 13a-d, the fastening sections 5a-d and the positioning sections 7a-c are arranged in such a manner and have such an axial extent that there is a first axial position of the component 1. FIG. 7 shows exactly this first axial position of the component 1 in which all fastening sections 5a-d fall completely within positioning regions 13a-d and all positioning sections 7a-c each overlap a fastening region 11a-d in axial direction.
[0075] Analogous to FIGS. 1 and 2, it is also true with this embodiment that the diameter of the support shaft 9 in the fastening regions 11a-d is greater than the diameter of the support shaft 9 in the positioning regions 13a-d. In addition it is also true here that the diameter of the passage opening 3 in the fastening sections 5a-d is smaller than the diameter of the passage opening 3 in the positioning sections 7a-c.
[0076] The embodiment shown in FIG. 7 is a particularly regular version with altogether four fastening regions 11a-d and four fastening sections 5a-d. In this version, all fastening regions 11a-d have the same axial extent and all positioning regions 13a-d likewise have the same axial extent. Furthermore, all fastening sections 5a-d and all positioning sections 7a-d each have the same axial extent. This produces a periodical tooth structure on the support shaft 9 and in the passage opening 3 of the component 1.
[0077] It is true, furthermore, in this embodiment that the sum of the axial extent of a positioning region 13a-d and of a fastening region 11a-d is equal to the sum of the axial extent of a positioning section 7a-c and of a fastening section 5a-d. This means that the outer contour of passage opening 3 and support shaft 9 each run periodically, wherein both have the same period. This same period has the advantage that the overlapping regions in the second axial position likewise have a regular periodical structure (with the same period). This becomes clear in the following by FIG. 8. Since the force transmission between support shaft 9 and component 1 takes place via these overlapping regions, this construction results in a highly uniform force transmission.
[0078] The configuration shown in FIG. 7, in which the component 1 assumes the first axial position, is established in that initially the support shaft 9 is cooled or the component 1 heated. Because of the temperature differential, different thermal deformations occur so that the support shaft 9 with its fastening regions 11a and 11b can be pushed through the passage opening 3 and simultaneously through the bearing mounts 19. In this state, the diameter of the passage opening in the fastening sections 5a and 5b is thus greater than the diameter of the fastening regions 11a and 11 b. Likewise, the diameter of the bearing mounts 19 in this state is greater than the diameter of the fastening regions 11a and 11b. Accordingly, sliding-in of the support shaft 9 is possible without problems. As soon as the first axial position of the component 1 has been adjusted, a temperature equalization is carried out, during which the support shaft 9 is heated and/or the component 1 is cooled, so that the diameter of the support shaft 9 in the fastening regions 11a-d is greater than the diameter of the passage opening 3 of the component 1 in the fastening sections 5a-d.
[0079] Once the desired angular position of the component 1 has been adjusted relative to the support shaft 9, while the component 1 is located in the first axial position shown in FIG. 7, the component is pressed on into the second axial position. The second axial position is shown in FIG. 8. During the pressing-on into the second axial position, the fastening regions 11a-d are plastically deformed so that the component 1 is connected with the support shaft 9 in a force-fit manner. In order to achieve this, the axial extent of the fastening regions 11a-d, of the positioning regions 13a-d, of the fastening sections 5a-d and of the positioning sections 7a-c is such that in the second axial position the fastening regions 11a-d at least partially overlap the fastening sections 5a-d. During the establishment of this overlap, the described plastic deformation occurs which fixes the component 1 on the support shaft 9 in a force-fit manner.
