Abstract
A method for positioning a cam element on a shaft segment of a camshaft with an assembly aid element may comprise arranging the shaft segment relative to a first tool such that a first distal shaft segment end of the shaft segment lies flush against a surface of the tool that is directed towards the shaft segment; arranging the cam element on the shaft segment in a pre-position; arranging a first distal end of the assembly aid element to contact the surface of the first tool that is directed towards the shaft segment such that the assembly aid element forms a defined distance to the first tool along a shaft-segment longitudinal axis; and moving a second tool at least in sections along the longitudinal axis until the second tool contacts a second distal end of the assembly aid element, and pushing the cam element by means of the second tool to a final position.
Claims
1.-9. (canceled)
10. A method for positioning a cam element on a shaft segment of a camshaft, the method comprising: positioning the shaft segment relative to a first tool such that a first distal shaft segment end of the shaft segment lies flush against a surface of the first tool that is directed towards the shaft segment; positioning the cam element on the shaft segment in a pre-position; positioning an assembly aid element so that a first distal end of the assembly aid element contacts the surface of the first tool that is directed towards the shaft segment, wherein the assembly aid element forms a defined distance to the first tool along a shaft-segment longitudinal axis; and moving a second tool at least in sections along the shaft-segment longitudinal axis until the second tool contacts a second distal end of the assembly aid element, whereby the second tool pushes the cam element from the pre-position to a final position.
11. The method of claim 10 wherein the assembly aid element is configured as an assembly sleeve.
12. The method of claim 10 wherein the assembly aid element is configured as an assembly mandrel.
13. The method of claim 10 wherein the first tool aligns the shaft segment in a machining position.
14. The method of claim 10 wherein the first tool is configured as a chuck.
15. The method of claim 10 wherein the first tool is configured as a machine chuck of an assembly plant.
16. The method of claim 10 wherein the first tool comprises an inner clamping mandrel, the method comprising using the inner clamping mandrel of the first tool to lock the shaft segment in a defined position.
17. The method of claim 10 wherein the second tool is configured as a gripper element.
18. The method of claim 10 wherein the second tool is configured as an assembly gripper.
19. The method of claim 18 comprising using the assembly gripper to position the cam element on the shaft segment, wherein a position of the cam element inside the assembly gripper is fixed via a projection that is formed on an axial lateral face of the cam element.
20. The method of claim 10 wherein the cam element is a first cam element, the method comprising positioning a second cam element on the shaft segment after the first cam element is positioned on the shaft segment in the pre-position, wherein the second tool moves the second cam element along the shaft-segment longitudinal axis into a final position of the second cam element at a same time as the second tool moves the first cam element along the shaft-segment longitudinal axis into the final position of the first cam element.
Description
[0022] A method according to the invention for positioning at least one cam element on a shaft segment of a camshaft by means of an assembly aid element is explained in more detail below with reference to the drawings. In the drawings, schematically in each case:
[0023] FIG. 1a shows in a lateral longitudinal sectional view a camshaft with cam elements positioned on a shaft segment, and with the specification of tolerances which is required by the client,
[0024] FIG. 1b shows in a lateral longitudinal sectional view a camshaft during the positioning of a first and a second cam element on a shaft segment according to an assembly method which is known from the prior art,
[0025] FIG. 1c shows in a lateral longitudinal sectional view the camshaft shown in FIG. 1b during the positioning of a third and a fourth cam element on the shaft segment by means of a corresponding tool,
[0026] FIG. 1d shows in a lateral longitudinal sectional view the camshaft shown in FIGS. 1b and 1c with cam elements positioned on a shaft segment and with the specification of the tolerances finally achieved by means of the method which is known from the prior art,
[0027] FIG. 2a shows in a lateral longitudinal sectional view a camshaft during the positioning of a cam element on a shaft segment by means of the method according to the invention,
[0028] FIG. 2b shows in a lateral longitudinal sectional view a camshaft during the positioning of a first cam element and a second cam element on the shaft segment by means of the method according to the invention,
[0029] FIG. 2c shows in a lateral longitudinal sectional view a camshaft during the positioning of a third and a fourth cam element on the shaft segment,
[0030] FIG. 2d shows in a lateral longitudinal sectional view a camshaft with specified tolerance measurements,
[0031] FIG. 3a shows in a lateral longitudinal sectional view a camshaft during the positioning of a cam element by means of the method according to the invention,
[0032] FIG. 3b shows in a lateral longitudinal sectional view a camshaft during the positioning of a first and a second cam element by means of the method according to the invention,
[0033] FIG. 3c shows in a lateral longitudinal sectional view the camshaft shown in FIGS. 3a and 3b during the positioning of a third and a fourth cam element on the shaft segment,
[0034] FIG. 3d shows in a lateral longitudinal sectional view the camshaft shown in FIGS. 3a to 3c and also the specification of correspondingly achieved tolerance measurements, and
[0035] FIG. 4 shows in a lateral longitudinal sectional view a camshaft during the positioning of a cam element on a shaft segment by means of the method according to the invention.
[0036] Elements with the same function and principle of operation are provided in each case with the same designations in the FIGS. 1a to 4.
[0037] Shown schematically in FIG. 1a is a longitudinal sectional view of a camshaft 20, especially a detail of a camshaft 20. The camshaft 20 comprises a shaft segment 5 and also cam elements 1 to 4. As shown in FIG. 1a, the camshaft 20 is shown halved along the shaft-segment longitudinal axis L. This halved view is also maintained in the following figures. The shaft-segment longitudinal axis is identified by the designation L and can also be advantageously referred to as the central shaft-segment longitudinal axis. Along the shaft-segment longitudinal axis L, as shown in FIG. 1a, four cam elements 1 to 4 are arranged on the shaft segment, wherein two cam elements 1 and 2 or 3 and 4 are arranged as a cam element pair in each case on the shaft segment 5. Also shown are tolerance measurements between the individual cam elements 1 to 4 which correspond to those tolerances which are required by the client. These tolerances need to be met during the assembly of the cam elements 1 to 4 on the shaft segment 5 of the camshaft 20.
[0038] The method known from the general prior art for positioning at least one cam element 1 on the shaft segment 5 for producing or creating a camshaft 20 is especially shown in FIG. 1b. For this, use is made of a tool 6 which moves the cam element 1 or a first cam element 1 and a second cam element 2 along the shaft-segment longitudinal axis L in the assembly direction M. It is clearly shown here that at least the first cam element 1 is moved from a pre-position 1.1 into a final position 1.2. The same is also to be said for the cam element 2 which if a pre-positioning of the second cam element 2 has taken place the second cam element 2 is moved from a pre-position 2.1 into a final position 2.2. The distal end 5.1 of the shaft segment 5 in this case forms the stop for the first tool 6 and consequently limits its movement along the shaft-segment longitudinal axis L in the assembly direction M.
[0039] After the fitting of the first cam element 1 and also of the second cam element 2, as known from the general prior art, a third cam element 3 and a fourth cam element 4 are advantageously fitted on the shaft segment 5. This is especially shown in FIG. 1c. By means of a further tool 6.1, the third cam element 3 and also the fourth cam element 4 are displaced along the shaft-segment longitudinal axis L in the same assembly direction M as the first cam element 1 and the second cam element 2 were previously moved. In the process, the third cam element 3 is advantageously moved from a pre-position 3.1 into a final position 3.2 on account of the pushing movement of the tool 6.1 and consequently of the fourth cam element 4 in the assembly direction M.
[0040] As shown in FIG. 1d, after the complete arranging of the cam elements 1 to 4 on the shaft segment 5 for creating a camshaft 20, especially the first tolerance measurement T1 or the first tolerance range T1, which describes the length from a front axial lateral face of the first cam element 1 to a rear axial lateral face of the third cam element 3, as well as the second tolerance measurement T2 or the second tolerance range T2, which describes the length from a front axial lateral face of the first cam element 1 to a front axial lateral face of the third cam element 3, are not met on account of different geometric measurements of the shaft segment 5 and/or of the individual cam elements 1 to 4 within the predetermined tolerance range. The tolerance measurements T1 and T2 which are achieved clearly exceed the tolerance measurements shown in FIG. 1a which are required by the client. An adjustment of the tolerance measurement T2 is advantageously possible by means of machining the third cam element 3 by for example the width of the third cam element 3 being reduced by grinding one of the lateral faces of the third cam element 3. Such machining cannot be implemented, however, in order to adjust the tolerance measurement T1 since machining of the rear axial lateral face of the third cam element 3 cannot be enabled on account of the arrangement of the fourth cam element 4. Consequently, it is necessary to optimize the entire assembly process in order to meet the (distance) tolerances which are required by the client.
[0041] The method claimed for this for positioning at least one cam element 1 on the shaft segment 5 is shown in FIGS. 2a to 4. Shown therefore in FIG. 2a in a lateral sectional view is a (halved) camshaft 20 which comprises a (halved) shaft segment 5 and a (halved) first cam element 1 which is to be arranged on the shaft segment 5. The cam element 1 is displaced by means of a second tool 7 along the shaft-segment longitudinal axis L in the assembly direction M from a pre-position 1.1 into a final position 1.2 in the direction of the first tool 6. The first tool 6 serves for arranging the shaft segment 5 in such a way that the first distal end 5.1 of the shaft segment 5 lies flush against a surface 6.2 of the first tool which is directed towards the shaft segment 5. Also shown in FIG. 2a is an assembly aid element 10 which for example is designed in the form of an assembly sleeve. The assembly aid element 10 extends along the shaft-segment longitudinal axis L from the tool surface 6.2 in the direction of the second tool 7. The assembly aid element 10 advantageously serves as a stop element for the second tool 7. A movement of the second tool 7 in the assembly direction M along the shaft-segment longitudinal axis L is limited by means of the assembly aid element 10, especially a (second) distal wall 10.2 of the assembly aid element 10 which is disposed opposite a first distal wall 10.1 of the assembly aid element 10. The first distal wall 10.1 of the assembly aid element 10 advantageously contacts the surface 6.2 of the first tool 6.
[0042] As shown in FIG. 2b, it is also conceivable that not only one cam element 1, but also two cam elements 1 and 2 can be moved at the same time from a pre-position 1.1 or 2.1 into a final position 1.2 or 2.2 by means of a second tool 7. To this end, a first cam element 1 and following that a second cam element 2 or vice versa is initially arranged on the shaft segment 5 in a pre-position 1.1 or 2.1. Following that, the second tool 7 is moved in the assembly direction M along the shaft-segment longitudinal axis L and at the same time pushes the first cam element 1 and the second cam element 2 into a final position 1.2 or 2.2. The displacement distance is limited by the assembly aid element 10 which serves as a stop element for the second tool 7. In comparison to the method known from the general prior art, as shown in FIGS. 1b and 1c, by means of the method according to the invention movement directly onto a stop is not by means of the axial rear side of the cam element 1, but rather the cam element 1 is moved on its axial front side by means of a tool 7, such as an anvil, until this tool 7 impacts against the assembly aid element 10, such as the assembly sleeve, which consequently forms a stop.
[0043] After the positioning the at least first cam element 1, a third 3 and a fourth cam element 4 can be arranged on the shaft segment 5, as shown in FIG. 2c. For this, the first tool 6 is briefly removed from the shaft segment 5, at least the third cam element 3 and advantageously also the fourth cam element 4 are pushed onto the shaft segment 5 into a pre-position and the first tool 6 is moved in the assembly direction M in such a way that at least the third cam element 3 is moved from a pre-position 3.1 into a final position 3.3.
[0044] It would, however, also be conceivable that the fourth cam element 4 is first of all fitted onto the shaft segment 5 in such a way that this contacts the first tool 6. Subsequently, the third cam element 3 is then advantageously pushed onto the shaft segment 5 until this contacts the fourth cam element 4. Accordingly, both cam elements 3 and 4 are already in their final position after their assembly on the shaft segment 5. The first tool 6 accordingly serves as a stop element for the fourth cam element 4 which in turn serves as a stop element for the third cam element 3. The second cam element 2 is then pushed onto the shaft segment 5 into a pre-position. The pre-position is created since no tool or other element serves as a stop element for the second cam element 2 and consequently determines its position, especially its final position, on the shaft segment. After the fitting of the second cam element 2, the first cam element 1 is fitted onto the shaft segment 5. The second tool 7, which displaces the first cam element 1 along the shaft-segment longitudinal axis L in the direction of the first tool 6, advantageously serves for this. On account of the displacement of the first cam element 1, the second cam element 2 is also displaced along the shaft-segment longitudinal axis L in the direction of the first tool 6 from a pre-position into final position. This takes place on account of the contacting of the first cam element 1 by the already pre-positioned second cam element 2 during the assembly process of the first cam element 1 on the shaft segment 5. The two cam elements 1 and 2 are displaced or moved until the second tool 7 contacts the assembly aid element 10, as a result of which the movement of the second tool 7 is limited in turn.
[0045] As shown in FIG. 2d, the method according to the invention enables the meeting of the tolerance range T1 which is predetermined by the client and optimizes at least the tolerance range T2 in comparison to the use of the method which is known in general from the prior art. Moreover, machining of the third cam element 3 also continues to be conceivable for achieving the predetermined tolerance range T2.
[0046] In FIGS. 3a to 3d, the method according to the invention is also schematically shown, wherein the assembly aid element 10 is not an assembly sleeve, as shown in FIGS. 2a to 2d, but an assembly mandrel. The assembly mandrel extends in this case through a through-hole 5.2 of the shaft segment 5. The first distal end 5.1 is again arranged flush with the surface 6.2 of the first tool 6 in this case so that a defined distance is created between the first tool 6 and the second tool 7 in order to limit a movement of the second tool when the second tool 7 is moved in the assembly direction M along the shaft-segment longitudinal axis L in the direction of the first tool 6. The assembly aid element 10, which consequently is designed in the form of an assembly mandrel, therefore serves as a stop for the second tool 7. The movement of the second tool 7 in the assembly direction M is stopped as soon as a surface 7.1 of the second tool 7 contacts the second distal end 10.2 of the assembly aid element 10. The same also applies with regard to its method for positioning a cam element 1 shown in FIG. 3b, in which at least two cam elements 1 or 2 are moved from a pre-position 1.2 or 2.1 into a final position 1.2 or 2.2 in the assembly direction M.
[0047] Shown in FIG. 3c, comparable to FIG. 2c, is the positioning of further cam elements 3 and 4 on the shaft segment 5. Consequently, reference is made to the description in relation to FIG. 2c in this case. Shown in FIG. 3d is the final positioning of the cam elements 1 to 4 on the shaft segment 5 for producing the finished camshaft 20. Corresponding to the camshaft 20 shown in FIG. 2d, it also becomes clear here that especially the tolerance measurement T1 or the tolerance range T1 is met by means of the method according to the invention, whereas the tolerance measurement T2 or the tolerance range T2 can be optimized for example by means of machining the third cam element 3 by means of a machining process.
[0048] Shown in FIG. 4 is the method according to the invention shown in FIGS. 2a to 2c or 3a to 3d, wherein an assembly mandrel is used as the assembly aid element 10. However, it is also conceivable to use an assembly sleeve as the assembly aid element 10. Comparable to FIG. 2a or 3a, a first cam element 1 is moved from a pre-position 1.1 into a final position 1.2 after the arranging on a shaft segment 5, wherein a second tool 7 is moved in the assembly direction M along a shaft-segment longitudinal axis L in the direction of the first tool 6. The first cam element 1, moreover, comprises at least one projection 11 which extends away from an axial lateral wall, especially from the front axial lateral wall. The projection 11 itself advantageously serves for creating a reference surface. In this case, it is advantageous to assume therefrom that the cam element 1 comprises more than one projection 11, advantageously two and particularly advantageously three projections 11 which are arranged on the axial lateral face of the first cam element 1 in a uniformly spaced apart manner.
[0049] It is furthermore conceivable that the first tool 6 comprises an inner clamping mandrel 12 which extends inside the bore of the shaft segment 5 from the surface 6.1 of the first tool 6, which is directed towards the shaft segment 5, at least in sections along the shaft-segment longitudinal axis L. This inner clamping mandrel advantageously serves for the positioning and/or locking of the shaft segment 5 on the first tool 6 so that an unwanted movement of the shaft segment 5 is avoided when arranging and positioning the at least first cam element 1.
[0050] The exemplary embodiments shown in FIGS. 2a to 4 do not determine the requirement of completeness and are only to be seen as being exemplary. The design of the individual tools, of the shaft segment and/or of the cam elements and also of the assembly aid element is only to be considered schematically and determines no completeness.
LIST OF DESIGNATIONS
[0051] 1 (First) cam element
[0052] 1.1 Pre-position of the (first) cam element
[0053] 1.2 Final position of the (first) cam element
[0054] 2 (Second) cam element
[0055] 2.1 Pre-position of the (second) cam element
[0056] 2.2 Final position of the (second) cam element
[0057] 3 (Third) cam element
[0058] 3.1 Pre-position of the (third) cam element
[0059] 3.2 Final position of the (third) cam element
[0060] 4 (Fourth) cam element
[0061] 5 Shaft segment
[0062] 5.1 First distal shaft segment end
[0063] 5.2 Through-hole
[0064] 6 First tool
[0065] 6.1 Further tool
[0066] 6.2 Surface of the first tool
[0067] 7 Second tool
[0068] 7.1 Surface of the second tool
[0069] 10 Assembly aid element
[0070] 10.1 First distal end of the assembly aid element
[0071] 10.2 Second distal end of the assembly aid element
[0072] 11 Projection
[0073] 12 Inner clamping mandrel
[0074] 20 Camshaft
[0075] L Shaft-segment longitudinal axis
[0076] M Assembly direction
[0077] T1 (First) tolerance measurement
[0078] T2 (Second) tolerance measurement
