Camshaft having an axially displaceable cam pack

Abstract

A camshaft includes a carrier shaft which can be mounted rotatably along a shaft axis and at least one cam pack disposed axially displaceably on the carrier shaft. The cam pack includes at least two cams and at least one adjusting member for axial adjustment of the cam pack. The cams and the at least one adjusting member are connected to one another in an axially adjacent configuration and can be mounted axially displaceably as a composite structure in a direct configuration on the carrier shaft. A method for producing a camshaft and a cam pack are also provided.

Claims

1. A camshaft, comprising: a carrier shaft configured to be mounted for rotation along a shaft axis, said carrier shaft having an outer toothing; at least one cam pack configured to be axially displaced on said carrier shaft, said at least one cam pack including at least two cams and at least one adjusting member configured to axially adjust said at least one cam pack; said cams and said at least one adjusting member connected to one another in an axially adjacent configuration and configured to be mounted for axially displacement as a composite structure in a direct configuration on said carrier shaft; said cams and said at least one adjusting member having a through-bore extending through and defined by said cams and said at least one adjusting member, said carrier shaft passing through said through-bore, said through-bore having an inner toothing engaging with said outer toothing in an axially displaceable and torque-transmitting manner; at least one multiple cam element having said at least two cams, said at least one adjusting member being an adjusting member connected to said at least one multiple cam element at a connection in an axially adjacent configuration, said multiple cam element including a jointing section configured to be at least one of introduced into a receiving bore of said adjusting member or pushed onto a receiving section of said adjusting member.

2. The camshaft according to claim 1, wherein said cams and said at least one adjusting member have end faces, and said cams and said at least one adjusting member are connected to one another by connections at least over partial regions of said respective end faces.

3. The camshaft according to claim 2, wherein said connections of said cams and said at least one adjusting member and cams disposed adjacent said at least one adjusting member include at least one tie rod extending through said cams and said at least one adjusting member.

4. The camshaft according to claim 2, wherein said connections are firmly bonded connections.

5. The camshaft according to claim 4, wherein said firmly bonded connections are weld joints.

6. The camshaft according to claim 5, wherein said weld joints are disposed on at least one of outer peripheries or inner peripheries of said cams and said at least one adjusting member.

7. The camshaft according to claim 4, wherein said firmly bonded connections between said cams and said at least one adjusting member and cams disposed adjacent said at least one adjusting member are solder joints or adhesive joints.

8. The camshaft according to claim 1, wherein said adjusting member has end faces and a jointing tongue at least on one of said end faces, and said multiple cam element has at least one jointing groove into which said jointing tongue is configured to be introduced to connect said multiple cam element to said adjusting member.

9. The camshaft according to claim 8, wherein said jointing tongue is a radially circumferential jointing tongue.

10. The camshaft according to claim 8, wherein said connection between said jointing tongue and said jointing groove is a compression joint.

11. The camshaft according to claim 1, wherein said connection between said multiple cam element and said adjusting member includes a compression joint, a weld joint, a solder joint or an adhesive joint.

12. The camshaft according to claim 1, wherein said connection between said jointing section and said receiving bore is a compression joint.

13. A cam pack, comprising: at least two cams; and at least one adjusting member configured to axial adjust the cam pack on a carrier shaft; said cams and said at least one adjusting member connected to one another in an axially adjacent configuration and forming a composite structure for direct configuration on the carrier shaft; said cams and said at least one adjusting member having a through-bore extending through and defined by said cams and said at least one adjusting member, said carrier shaft passing through said through bore, said through-bore having an inner toothing engaging with an outer toothing on the carrier shaft in an axially displaceable and torque-transmitting manner; at least one multiple cam element having said at least two cams, said at least one adjusting member being an adjusting member connected to said at least one multiple cam element at a connection in an axially adjacent configuration, said multiple cam element including a jointing section configured to be at least one of introduced into a receiving bore of said adjusting member or pushed onto a receiving section of said adjusting member.

14. A method for producing a camshaft, the method comprising the following steps: providing a carrier shaft configured to be mounted for rotation along a shaft axis; providing a cam pack including at least two cams and at least one adjusting member configured to axially adjust the cam pack; placing the cam pack axially displaceably on the carrier shaft; and mutually joining the at least two cams and the at least one adjusting member and adjacent cams of the at least two cams disposed adjacent the at least one adjusting member in an axially adjacent configuration and as a composite structure in a direct configuration on the carrier shaft; forming an inner toothing into the at least two cams and into the at least one adjusting member, engaging the inner toothing with an outer toothing on the carrier shaft in an axially displaceable manner; providing a multiple cam element having the at least two cams; and providing the at least one adjusting member as an adjusting member connected to the multiple cam element in an axially adjacent configuration; providing the multiple cam element with an end-face jointing section, and introducing the end-face jointing section into a receiving bore of the adjusting member; pressing the end-face jointing section into the receiving bore.

15. The method according to claim 14, which further comprises carrying out the step of forming the inner toothing into the at least two cams and into the adjusting member individually, and then carrying out the step of mutually joining the at least two cams and the at least one adjusting member in the axially adjacent configuration.

16. The method according to claim 14, which further comprises carrying out the step of mutually joining the at least two cams and the adjusting member in the axially adjacent configuration, and then carrying out the step of forming the inner toothing into the at least two cams and into the adjusting member.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) Further features improving the invention are represented in greater detail below with the aid of the figures, together with the description of preferred examples of embodiment of the invention. In the figures:

(2) FIG. 1 shows a cross-sectional view through a camshaft with a cam pack, which is constituted with the features of the present invention,

(3) FIG. 2 shows a cross-sectional view of a cam pack according to a first example of embodiment for the formation of the connections between the cams and the adjusting member,

(4) FIG. 3 shows a cross-sectional view of a cam pack according to a second example of embodiment for the formation of the connections between the cams and the adjusting member,

(5) FIG. 4 shows a cross-sectional view of a cam pack according to a further example of embodiment for the formation of the connections between the cams and the adjusting member,

(6) FIG. 5 shows a further example of embodiment of a cam pack, which comprises a bearing element for the mounting in a bearing,

(7) FIG. 6 shows a further example of embodiment of a cam pack, which comprises a multiple cam element and an adjusting member,

(8) FIG. 7 shows the example of embodiment of the cam pack according to FIG. 6 in a perspective view,

(9) FIG. 8 shows a further example of embodiment of a cam pack comprising two multiple cam elements and an adjusting member,

(10) FIG. 9 shows the example of embodiment of a cam pack according to FIG. 8 in a perspective view,

(11) FIG. 10 shows an example of embodiment of a cam pack with a multiple cam element, which is connected to the adjusting member by means of a jointing tongue and

(12) FIG. 11 shows a further example of embodiment of a cam pack with two multiple cam elements, which are each connected to the adjusting member by means of a jointing tongue.

DESCRIPTION OF THE INVENTION

(13) FIG. 1 shows an example of embodiment of a camshaft 1 with a cam pack 12, which is constituted with the features of the present invention. Camshaft 1 comprises a carrier shaft 10, which is shown interrupted in the seating region of cam pack 12. Carrier shaft 10 can be mounted rotatably in a shaft axis 11, for example in the cylinder head of an internal combustion engine.

(14) Cam pack 12 comprises for example six cams 13, 14, 26, 27, 28 and 29, wherein an adjusting member 15 is provided, and a groove guide 30 is introduced in adjusting member 15 on the outer periphery of the adjusting member 15. Cams 13, 14 and 26 are located on a first side of adjusting member 15, and cams 27, 28 and 29 are located on an opposite, second side of adjusting member 15. A through-bore, through which carrier shaft 10 is passed, extends through cams 13, 14, 26, 27, 28, 29 and through adjusting member 15. An inner toothing 16 is introduced in this through-bore formed by the individual components of cam pack 12, said inner toothing engaging with an outer toothing 17 on carrier shaft 10 in an axially displaceable and torque-transmitting manner. Outer toothing 17 of carrier shaft 10 is constituted wider in the direction of shaft axis 11 than the width of cam pack 12, and cam pack 12 can be adjusted axially in the direction of the shaft axis, whereby an adjusting element is guided in groove guide 30 of adjusting member 15. As a result of the form-fit connection of inner toothing 16 and outer toothing 17, a rotary motion of the carrier shaft 10 is at the same time transmitted to cam pack 12.

(15) Cams 13, 14, 26, 27, 28, 29 and adjusting member 15 are connected to one another in an axially adjacent arrangement with one another, so that, as a result of the connection of these components of cam pack 12 via their respective end faces constituted in the axial direction, a composite structure is created which forms cam pack 12. According to the invention, this does not require a carrier tube on which the individual components such as cams 13, 14, 26, 27, 28, 29 and adjusting member 15 have to be disposed. Inner toothing 16 and latching grooves 18 can thus be introduced directly into cams 13, 14, 26, 27, 28, 29 and into adjusting member 15, wherein for example three latching grooves 18 are introduced on the inside into adjusting member 15, which are able to cooperate with a latching means for the axial latching of cam pack 12, said latching means being disposed in carrier shaft 10 in a manner not shown in detail.

(16) Cams 13, 14, 26, 27, 28, 29 each have different cam contours, for example cams 13, 14, 26, 27, 28, 29 can have different cam lobes or the cam lobes are constituted at different angles around the circumference. As a result of the axial adjustability of cam pack 12, tappets having a fixed axial position can cooperate with different cams 13, 14, 26 or 27, 28, 29, in order for example to change the valve lift, but also for example to change the valve control times.

(17) FIG. 2 shows a first example of embodiment for the formation of the composite structure of cams 13, 14, 26, 27, 28, 29 and adjusting member 15. The connection is constituted by tie rods 22, and by way of example two tie rods 22 are represented over the periphery of cam pack 12, wherein in particular more than two tie rods 22 can be provided, which are disposed uniformly distributed on the periphery of cam pack 12. Tie rods 22 extend parallel to shaft axis 11 through cams 13, 14, 26, 27, 28, 29 and adjusting member 15 and are placed under axial tensile stress. The components of cam pack 12 are thus pressed against one another at the end faces in order to form a mechanically loadable composite structure. Tie rods 22 can be constituted as screw elements or as dowel pins, in order to introduce a tensile stress into tie rods 22.

(18) FIG. 3 shows a further example of embodiment for the formation of cam pack 12, wherein the connections between cams 13, 14, 26, 27, 28, 29 and adjusting member 15 are constituted by weld joints 19, 20. Weld joints 19 are constituted as weld joints on the outer periphery and weld joints 20 are constituted as weld joints on the inner periphery. Weld joints 19 and 20 constituted on the outer periphery and on the inner periphery are shown merely by way of example, wherein for example only weld joints 20 on the inner periphery may be sufficient to form a mechanically loadable composite structure of the components of cam pack 12. Weld joints 19 and 20 can be produced for example by laser beam welding procedures or by electron beam welding procedures, in order to minimize the thermal effect on cams 13, 14, 26, 27, 28, 29 and adjusting member 15.

(19) FIG. 4 shows a further example of embodiment for the formation of cam pack 12, wherein cams 13, 14, 26, 27, 28, 29 are connected to one another and adjusting member 15 to adjacent cams 26, 27 by solder joints 21. Solder joints 21 can be prepared for example by soldering foils, which are disposed between the individual components of cam pack 12 and, after the arrangement of cams 13, 14, 26, 27, 28, 29 and adjusting member 15 in an axially adjacent arrangement with respect to one another, cam pack 12 thus prepared can be brought to the solder melting temperature in order to finish solder joints 21. As an alternative to shown solder joints 21, adhesive joints can be provided between the components of cam pack 12.

(20) Finally, FIG. 5 shows a further embodiment of a cam pack 12 with an adjusting member 15 and cams 13, 14, 26, 27, 28, 29, wherein cam 27 is also constituted as a bearing element 23. The cam 27 is constituted as a zero-lift cam and has a cylindrical outer circumference. Besides the tappingnot shown in detailby means of a tappet for the valve control, cam pack 12 is mounted in a bearing block 24, into which a bearing 25 is introduced. Cam 27 thus performs both as a zero-lift function for the valve control as well as the function for the bearing of cam pack 12. The connection between the components of cam pack 12 can be constituted according to the example of embodiment in FIG. 2, in FIG. 3 or in FIG. 4.

(21) As a result, a cam pack 12 is created which can be constituted without the use of a carrier tube. Furthermore, the possibility remains of feeding the different components of cam pack 12 in each case individually to mechanical and/or thermal processing steps, the components only then being connected to one another to form a cam pack 12.

(22) Inner toothing 16, which is introduced into cams 13, 14, 26, 27, 28, 29 and into adjusting member 15, can be introduced individually into the respective components before the creation of the jointing connections or inner toothing 16 is introduced into cam pack 12 when the jointing connections between the individual components have already been created.

(23) FIG. 6 shows a cross-sectional view and FIG. 7 a perspective view of a cam pack 12 according to a further example of embodiment. Cam pack 12 comprises a multiple cam element 31, and cams 32, 33 and 34 with different cam profiles are constituted on the outer periphery of multiple cam element 31. Multiple cam element 31 comprises a central through-hole along shaft axis 11 in which an inner toothing 16 is introduced, which can be engaged with an outer toothing 17 of carrier shaft 10, see in this regard FIG. 1. It is shown that inner toothing 16 is not constituted continuously in multiple cam element 31, but rather inner toothing 16 extends only over sections in respect of shaft axis 11. Latching grooves 18 are introduced between the sections of inner toothing 16, said latching grooves being able to cooperate with a latching means for the axial latching of cam pack 12, said latching means being able to be accommodated in carrier shaft 10 in a manner not shown in detail.

(24) Multiple cam element 31 is shown in an adjacent arrangement with respect to an adjusting member 35 and is connected to the latter. For the connection between multiple cam element 31 and adjusting member 35, multiple cam element 31 comprises a jointing section 36, by means of which a circumferential cylindrical connecting surface 40 is formed on the outside. Furthermore, adjusting member 35 comprises a receiving bore 37 with a connecting surface 41. Jointing section 36 is introduced, for example pressed, into receiving bore 37. In a manner not shown in detail, jointing section 36 can alternatively or additionally be welded, soldered or glued in receiving bore 37, in order to create a mechanically loadable connection between multiple cam element 31 and adjusting member 35.

(25) FIGS. 8 and 9 show a further example of embodiment of a cam pack 12 in a cross-sectional view and in a perspective view. The example of embodiment comprises two multiple cam elements 31, and cams 32, 33 and 34 are constituted in each case on the outer periphery of multiple cam elements 31. Both multiple cam elements 31 are connected to adjusting member 35, wherein the connection is carried out in the same way as already shown and described by FIG. 6.

(26) Multiple cam elements 31 comprise an inner toothing 16 on the inside, wherein for example multiple cam element 31 represented to the right of adjusting member 35 also comprises three latching grooves 18, as a result of which an interruption of inner toothing 16 again results, whereas multiple cam element 31 disposed to the left of adjusting member 35 comprises a continuous inner toothing 16 along shaft axis 11. The two multiple cam elements 35 are pressed, for example, into the receiving bore of the adjusting member lying opposite one another.

(27) FIGS. 10 and 11 show further examples of embodiment of cam packs 12, and FIG. 10 shows an example of embodiment with an adjusting member 35, to which only one multiple cam element 31 is fitted. FIG. 11, on the other hand, shows an example of embodiment with an adjusting member 35, and a first multiple cam element 31 is disposed on a first side and a further multiple cam element 31 is disposed on an opposite, second side of adjusting member 35. All multiple cam elements 31 comprise cams 32, 33 and 34 on their outer periphery, an inner toothing 16 being shown on the inside of multiple cam elements 31, said inner toothing comprising a plurality of interruptions in the circumferential direction. Multiple cam elements 31 shown in FIG. 11 on the right-hand side of adjusting member 35 also comprises latching grooves 16.

(28) The connection between adjusting members 35 and multiple cam elements 31 in FIGS. 10 and 11 is constituted by a tongue-and-groove system. Adjusting members 35 comprise jointing tongues 38 disposed on the end faces, said jointing tongues engaging in circumferential jointing grooves 39 and being introduced into multiple cam elements 31 likewise on the end faces. Jointing tongues 38 and jointing grooves 39 can be constituted around the entire circumference or jointing tongues 38 and jointing grooves 39 are disposed over limited segments on the periphery of adjusting member 35 and of multiple cam elements 31.

(29) The holding arrangement of jointing tongues 38 in jointing grooves 39 can be carried out by pressing jointing tongues 38 into jointing grooves 39, wherein welding, soldering or adhesion of jointing tongues 38 in jointing grooves 39 can also be provided after the jointing of jointing tongues 38 in jointing grooves 39. In particular, weld joints between jointing tongues 38 and jointing grooves 39 can be produced particularly advantageously by means of a laser beam capillary welding procedure, without thermal distortion being created in the formed cam pack 12, since the heat input into the component is minimal due to the use of a laser beam as a heat source for the welding.

(30) The invention is not limited in its implementation to the aforementioned preferred examples of embodiment. On the contrary, a number of variants are conceivable, which make use of the presented solution even with fundamentally different embodiments. All the features and/or advantages emerging from the claims, the description or the drawings, including structural details or spatial arrangements, may be essential to the invention both in themselves and as well as in the most varied combinations.

LIST OF REFERENCE NUMBERS

(31) 1 camshaft 10 carrier shaft 11 shaft axis 12 cam pack 13 cam, 13a end face 14 cam, 14a end face 15 adjusting member, 15a end face 16 inner toothing 17 outer toothing 18 latching groove 19 weld joint on the outer periphery 20 weld joint on the inner periphery 21 solder joint 22 tie rod 23 bearing element 24 bearing block 25 bearing 26 cam 27 cam 27 cam 28 cam 29 cam 30 groove guide 31 multiple cam element 32 cam 33 cam 34 cam 35 adjusting member 36 jointing section 37 receiving bore 38 jointing tongue 39 jointing groove 40 connecting surface 41 connecting surface