EP2649281B1 - Camshaft assembly and method of production - Google Patents

Description

The invention relates to a camshaft assembly comprising a receiving space in its interior, i. At least partially formed as a hollow shaft camshaft, at least in sections, in particular in the range of an electromagnetic actuator, from a magnetizable (flow-conducting) material for an internal combustion engine and an electromagnetic actuator for actuating a Stellpartners, in particular a control valve of a, preferably hydraulic, camshaft adjuster, with a coil winding and an adjustable by energizing the coil winding armature for cooperation with the control partner according to the preamble of claim 1. Further, the invention relates to a method for producing such a camshaft assembly according to the preamble of claim 12 and an engine block according to claim 16.

A camshaft assembly comprising a hydraulic phaser is in the EP 1 596 040 A2 described. The camshaft adjuster is used to set the opening or closing time of gas exchange valves of the internal combustion engine.

In the DE 10 2006 031 517 A1 an alternative camshaft assembly is described, comprising a camshaft adjuster whose control valve is adjustable by means of an electromagnetic actuator. The electromagnetic actuator of the known camshaft assembly is disposed on the front side of the camshaft and cooperates axially with the arranged in the camshaft control valve of the camshaft adjuster together.

From the JP 2010 190060 A a camshaft assembly is known in which a coil winding for contactless adjustment of an armature along the camshaft rotation axis is disposed within the camshaft.

From the EP 2 252 774 B1 a camshaft assembly is known in which the coil winding is arranged to actuate a cooperating with a control valve of a camshaft adjuster armature in a housing outside of the engine block, with axial distance to the fully recorded in the engine view camshaft. At this a projecting into the housing for the coil winding yoke and core unit is fixed, wherein the yoke and core of the yoke and core unit are connected to each other via non-magnetic material. A disadvantage of the known camshaft assembly is that it has a comparatively high space requirement.

There are efforts to reduce the high space requirement of camshaft assemblies.

The invention is therefore based on the object to provide an alternative camshaft assembly whose space requirements, in particular in the region of the end face of the camshaft, is reduced. Furthermore, the object is to provide a method for producing such a space-optimized camshaft assembly.

With regard to the camshaft assembly, the object is achieved with the features of patent claim 1 and with regard to the manufacturing method for producing such a camshaft assembly having the features of claim 12.

Advantageous developments of the invention are specified in the subclaims. All combinations of at least two features disclosed in the description, the claims and / or the figures fall within the scope of the invention. To avoid repetition Device-disclosed features as disclosed according to the method apply and be claimable. Likewise, according to the method disclosed features should be considered as device disclosed and claimed claimable.

The invention is based on the idea of arranging the armature, at least in sections, preferably completely, inside the camshaft, at least partially designed as a hollow shaft, ie in a receiving space formed in the interior of the camshaft and the coil winding for adjusting the armature radially spaced from the armature, and although outside the camshaft. In order to generate a sufficiently strong magnetic flux from the coil winding to the armature and back again when the coil winding is energized, it is provided according to the invention that the camshaft has a first and a second axial section, between which a material region influencing the magnetic flux is provided and it is intended to increase the magnetic flux from one of the axial sections to the respective other axial section (in comparison to a design without such a material section) via the armature and via the possibly oil-filled air reservoir provided between the inner circumference of the camshaft and the armature. The material region is thus such that it "forces" the magnetic flux, at least for the most part, very particularly preferably completely from one of the axial sections to the armature and from the armature to the respective other axial section such that the magnetic flux blocks the distance between the axial sections and the axial section Crossing anchor and taking the "detour" over the anchor. As a result, a space-saving, efficiency-optimized design of the electromagnetic actuator is obtained. Theoretically, it would be conceivable to form the, preferably radial break-free, camshaft made of a non-magnetizable material, so as to dispense with two spaced over a material range axial sections - but this alternative solution would have the disadvantage that a. Magnetic non-conductive radial distance between the coil winding and armature comparatively large-sized coil winding would have to be used to ensure an adjustment of the armature. In contrast, comes a camshaft assembly according to the invention with comparatively small-sized coil winding, so that the camshaft assembly according to the invention is space-optimized not only in the axial direction, but also in the radial direction.

Preferably, an axially adjacent to the camshaft yoke and core unit is dispensed with, since this function is taken over by the first and the second axial portion of the camshaft.

An embodiment is preferred in which the camshaft is arranged completely within an engine block. More preferably, the armature and the coil winding are also completely within the engine block and not as in the prior art on a fixed outside of the engine block housing, which is preferably completely omitted according to further development.

It is very particularly preferred if the region influencing the magnetic flux does not protrude in the radial direction beyond the axially adjacent camshaft sections or over their, preferably common, cylindrical, enveloping contour.

In order to effect an optimum influencing of the magnetic flux in the manner described above, the invention provides that the material forming the material region, ie the material that is comprised in the material region or of which it consists, is not magnetically conductive or at least less magnetically conductive than the (other) material of the camshaft. In this context, it is defined that the claimed magnetizable material of the camshaft is to be understood as meaning the material or the material combinations of the camshaft adjacent to the material region influencing the magnetic flux, ie the material (s) from which or which the axial sections are formed. Due to the formation of the magnetic flux influencing material area of a not or at least less magnetizable material, preferably metal, for example bearing materials, such as brass, an optimal magnetic separation between the two axial sections is achieved. This magnetic separation can be completely or only partially realized, depending on whether the two axial sections are connected to each other exclusively via the material region influencing the magnetic flux, or whether a material bridge of camshaft material is provided in addition to the material region. The quality or the extent of the magnetic separation is also influenced by the choice of material of the material area, ie by whether non-magnetizable or difficult to magnetize material is used.

In the present application is meant "magnetizable" in the sense of "flux-conducting", i. a magnetizable material is flux-conducting, whereas a hardly magnetizable material is poorly flux-conducting, i. the hard magnetizable material provides a great resistance to the magnetic flux. Non-magnetizable material is not flux-conducting. "Magnetizable" means not a possible remanence (magnetizability) of the material but that a significant magnetization of the material under external magnetic field occurs.

It is preferred if the camshaft, preferably at least in the region of the setting unit (actuator region), is formed from magnetizable (flux-conducting) material, in particular a suitable steel.

Especially preferred is a variant in which the first and the second axial section, in particular exclusively, are mechanically fixed to one another via the material region. This can be realized in particular by the fact that the first and the second axial section are connected to one another by welding, in particular build-up welding, using material that is not or only slightly magnetically conductive. As an alternative to a welding process, it is conceivable that the material region is formed by a solder material which, although the Material sections mechanically bonded together, but in contrast to a welding process does not produce a material-locking, yet a mechanically strong connection. Preferably, the camshaft surface (surface) is processed after welding or soldering, in particular smoothed, for example by twisting and / or grinding.

For example, as an alternative to applying an additional material, in particular a solder or welding material for forming the material region, it is possible to realize or form the material region by a material change in a section axially between the two axial sections of the camshaft. This can be achieved, for example, by partial heat treatment, in particular annealing or other method of structural transformation.

Another alternative production possibility is to provide as the magnetic flux influencing material area between the first and the second axial section, a ring member or hollow cylinder member of a non- or poorly magnetically conductive material, such as brass, which in a suitable manner, for example by friction welding with the two axial sections, preferably connected to the mutually facing end faces of the axial sections.

It is particularly preferred if the material region between the two axial sections of the camshaft is generated by filling a clearance with, preferably not or poorly magnetizable material, wherein the free space can be a recess, in particular a circumferential groove in the camshaft, that is, in addition to the free space, in particular radially inward adjacent one, preferably as thin as possible, connection of camshaft material between the two axial sections of the camshaft remains. Alternatively, the free space may be a complete separation, ie a radially continuous, in particular circumferentially closed, gap or axial distance between the two Axial sections of the camshaft act. As will be seen in the explanation of the method according to the invention or a preferred embodiment of the method, it is particularly useful if the production of the free space by making a recess or complete separation of the two axial sections of the camshaft in the same clamping, so that the both axial sections remain exactly positioned to each other and no re-relative positioning is necessary.

As already explained, it is particularly expedient if the free space is filled by build-up welding, in which case the non or poorly conducting magnetic material is applied in a fluid, heated state.

As already indicated above, it is conceivable in principle that the two axial sections of the camshaft are not held together exclusively over the material region of non-magnetizable or poorly magnetizable material, but that directly adjacent to the material region, in particular radially inside, an axial, preferably annular, yet more preferably as thin as possible, ie the smallest possible radial extent exhibiting connecting web or connecting ring is provided. Preferably, this connecting portion, in particular ring portion designed so thin or provided with such a thin cross section in the radial direction that when energizing the coil winding (fast) a magnetic saturation is achieved, whereby negative effects of the magnetizable connection portion are minimized to the efficiency of the electromagnetic actuator ,

Particularly preferred is an embodiment in which the camshaft, except for the area influencing the magnetic flux, has a maximum of two parts, ie not more than two parts. A one-piece design is possible if the two axial sections, as described above, are connected to one another via a material bridge or the region influencing the magnetic flux by structural transformation of a Camshaft section is generated. In a two-part embodiment, the two axial sections are connected to one another (preferably exclusively) via the material region influencing the magnetic flux. More preferably, the camshaft has an axially continuous cylindrical outer contour.

With regard to the geometric configuration of the non-magnetizable or poorly magnetizable material region, there are different alternatives. In principle, it is possible to provide the material region with a rectangular cross-section contour. It is particularly expedient, in particular in order to obtain the largest possible connecting or fixing surfaces between the axial sections and the material region, when the connecting surfaces or holding surfaces between the material region and the axial sections are formed obliquely. This can be achieved, for example, by extending the axial extent of the material region over its radial extension, i. looking towards the anchor decreases.

In order to achieve the best possible magnetic separation between the two axial sections, it is preferred if the material area of non-magnetizable or heavily magnetizable material is circumferentially closed, i. is annular.

With regard to the arrangement of the coil winding, there are several alternatives. According to a particularly preferred embodiment, the coil winding is arranged coaxially to the camshaft, thus enclosing this ring. Alternatively, the coil winding is arranged next to the camshaft, preferably in such a way that a coil winding axis runs parallel to the camshaft. It is also conceivable to arrange a plurality of circumferentially juxtaposed, i. Provide distributed over the circumference of the camshaft coil windings.

According to the invention, the armature is at least partially in the camshaft, more specifically provided in the camshaft, preferably taken from this limited recording room. It is particularly expedient with regard to an optimized space requirement if the armature is arranged over the largest part of its axial extent, preferably completely in the camshaft. It is likewise preferred if the control partner, in particular a control valve of a camshaft adjuster with which the armature cooperates, is received at least in sections, preferably completely in the camshaft. It is particularly expedient if the setting partner projects at least axially from one end face into the camshaft.

The invention also leads to a method for producing a camshaft assembly according to the invention. The core of the method is that in an (intermediate) area between a first axial section and a second axial section of a camshaft, preferably the two axial sections mechanically firmly interconnecting, material region is provided so that thereby a magnetic flux guide is effected, in which the magnetic flux is increased from one of the axial sections of the camshaft to the respective other axial section via the armature (compared to a variant without such a material region).

With regard to the generation of the material area, there are different possibilities. It is particularly preferable to produce the material region by filling, for example by means of build-up welding, a free space between the two axial sections with a material which is not or at least less easily magnetizable than the material of the two axial sections of the camshaft. The two axial sections of the camshaft preferably consist of the same material. In principle, a variant embodiment is conceivable in which the two camshaft axial sections consist of different materials.

Before filling the free space of this is preferably prepared, alternatively by machining a camshaft blank, for example by Inserting a groove or by separating a previously one-piece camshaft body blank, wherein it is particularly preferred if the production of the free space in the same clamping takes place as the filling of the free space, to avoid repositioning of the two axial sections in the case of complete separation.

Alternatively, it is possible to position two camshaft body blanks, which later form the two axial sections of the camshaft, while maintaining the clearance, and then to fill up the clearance with, in particular, non-magnetizable or at least less readily magnetizable material, for example by build-up welding.

According to an alternative production variant of the material region, preferably no clearance is filled up, but the originally magnetizable material of the camshaft body blank is partially processed (changed), so that the material in the later material region is not or at least less easily magnetizable than the material of the first and / or second axial section. For this purpose, the material in the later material area, for example, partially processed by heat treatment.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawings.

Fig. 1

in einer stark schematisierten nur hälftig dargestellten, geschnittenen Ansicht eine Nockenwellebaugruppe, bei der zwei Axialabschnitte der Nockenwelle ausschließlich über einen Materialbereich aus nicht- magnetisierbarem Material axial fest miteinander verbunden sind, und

Fig. 2

eine alternative Ausführungsvariante der Nockenwellenbaugruppe, bei der die beiden Axialabschnitte zusätzlich zu dem Materialbereich über einen ringförmigen Verbindungsabschnitt aus Nockenwellenmaterial miteinander verbunden sind, wobei die Radialerstreckung dieses Verbindungsbereichs so gewählt ist, dass dieser Bereich bei Bestromung einer Spulenwicklung rasch magnetisch gesättigt wird.

These show in:

Fig. 1

in a highly schematized half-cut view, a camshaft assembly in which two axial sections of the camshaft are axially fixed together exclusively over a material area of nichtmagnetisierbarem material, and

Fig. 2

an alternative embodiment of the camshaft assembly, in which the two axial sections are connected to each other in addition to the material region via an annular connecting portion of camshaft material, wherein the radial extent of this connection region is selected so that this area is rapidly magnetically saturated when energized a coil winding.

In the figures, like elements and elements having the same function are denoted by the same reference numerals.

In Fig. 1 is a schematic longitudinal sectional view of a camshaft assembly with a hollow camshaft of a magnetizable material, here steel, and a hydraulic camshaft adjuster 3, an electromagnetic actuator 4 and a control partner 5 for the electromagnetic actuator in the form of a control valve of the camshaft adjuster 3 shown. The camshaft adjuster 3 is arranged and fixed together with control partner 5 (control valve) on the camshaft 2 in a conventional manner. A not separately shown camshaft adjuster housing is directly or indirectly connected to a likewise not shown crankshaft of the internal combustion engine, also not shown, and driven by this. In addition, the camshaft adjuster 3 with the camshaft 2 connected, not shown adjusting, which can be rotated by a hydraulic actuation in a conventional manner relative to the camshaft adjuster housing. The rotation of these adjusting causes a phase adjustment of the camshaft 2 relative to the crankshaft.

The electromagnetic setting unit 4 comprises an armature 7 arranged in the camshaft 2, more precisely in a receiving space 6 of the camshaft 2, which is mounted axially displaceable and by energizing a coil winding 8 arranged radially outside and at a distance from the camshaft 2 in the axial direction of the camshaft 2 is adjustable. The armature 7 is axial arranged adjacent to the adjusting partner 5, which is alternatively arranged completely in the camshaft 2 and projects axially into it. It is also conceivable that the control partner is located outside the camshaft 2 and the armature 7 protrudes a distance from the camshaft 2.
As explained, the control partner 5 is a control valve of the camshaft adjuster 3, wherein the camshaft adjuster 3 can be controlled by the hydraulic camshaft adjuster 3 by the control valve (control partner 5) in an amount required for the desired adjustment and the necessary pressure causing hydraulic fluid is supplied. By the hydraulic fluid, the adjusting elements of the camshaft adjuster 3 are rotated relative to the housing of the camshaft adjuster 3, which then, as explained in a phase adjustment of the camshaft 2 results.

How out Fig. 1 can be seen, the camshaft 2 comprises a first axial portion 9 and a second axial portion 10. Between the first and the second axial portion 9, 10, a magnetic flux influencing material region 11 is provided from a no or only poorly magnetizable material. In the embodiment shown according to Fig. 1 the two axial sections 9, 10 are fixed to one another or connected to one another exclusively via this material region 11. The material region 11 forms a complete or partial magnetic separation of the two axial sections 9, 10. The material region 11 serves to draw the merely schematically drawn magnetic flux 12 from one of the axial sections via an optionally oil-filled or air-filled (peripheral) gap 13 to the armature 7 to pass, which is penetrated axially by the magnetic flux 12 and then again from the armature 7 back across the gap 13 to the other axial portion.

Out Fig. 1 It can be seen that the coil winding 8 is arranged coaxially to the camshaft 2 or to the longitudinal center axis 14 of the camshaft 2 with a radial distance from the camshaft 2. Between the camshaft 2 and the coil winding 8, a small circumferential air gap 15 is realized, so that the camshaft 2 can rotate relative to the stationarily arranged coil winding 8. Alternatively, the camshaft can not be arranged coaxially but parallel to the camshaft 2.

The coil winding 8 are associated with a first and a second yoke portion 16, 17, which are formed annular disk-shaped and extending in the radial direction. The two yoke sections 16, 17 are connected to one another in the axial direction by a, here hollow-cylindrical, magnetizable housing 18. In the exemplary embodiment shown, the first, yoke section 16, the second yoke section 17 and the housing 18 are separate, interconnected components, wherein in an alternative embodiment, at least one of the yoke sections 16, 17 may be integrally connected to the housing 18.

When the coil winding 8 is energized, the magnetic flux 12 shown only schematically results, with the flow direction and thus the direction of movement of the armature 7 being dependent on the current flow direction of the coil winding 8. In the exemplary embodiment shown, the magnetic flux extends from the radially inner end of the first yoke section 16 in the radial direction outwardly into the cylindrical housing 18, in this in the axial direction to the radially outer end of the second yoke portion 17 and then in the second yoke portion 17 radially inward, then bridges a second gap 19 between the second yoke portion 17 and the second axial portion , passes through the second axial portion substantially in the radial direction inwardly, then bridges the gap 13 towards the armature 7, extends in the armature 7 in the axial direction, then bridged again in the radial direction outwardly the gap 13 into the first axial section 9 and extends in this radially outwardly and bridges a first gap 20 between the first axial section 9 and the first yoke section 16.

In a preferred embodiment, a provision, either away from the control partner or on the control partner to be done by means of, for example, a mechanical adjustment mechanism, in particular via a Spring mechanism (not shown). To limit the axial displacement movement of the armature 7 in the direction of the actuator 5 away in the illustrated embodiment, a schematically illustrated axial stop 21, provided on the side facing away from the actuator 5 side of the armature 7.

In the embodiment according to Fig. 1 the armature 7 is designed in several parts and comprises a sleeve portion 22 to which a bolt portion 23, for example by pressing, is fixed. In the bolt portion 23, a ball 24 is rotatably supported in a cage at the front, wherein the armature 7 is supported on the ball 24 axially on the adjusting partner 5.

In the embodiment according to Fig. 1 the material region 11 was produced by build-up welding. For this purpose, a camshaft body blank made of magnetizable material in the region of the current material region 11 was divided into two separate axial sections, which now form the first and second axial section 9, 10. These two axial sections were fixedly joined together by build-up welding of non-magnetizable material 11, ie by producing the material region 11, in a material-locking manner. It can be seen that the axial extent of the material region decreases from radially outward to radially inward, and that at least one oblique contact surface is formed on each axial section 9, 10 in order to increase the contact surfaces to the material region 11 and thus the strength of the system.

Alternatively, it is also possible to realize the magnetic separation between the two axial sections 9, 10, for example by providing as the material region 11 a ring of a non- or only difficult-to-magnetize material in order to separate the two separate, ie. later axial sections 9, 10 to connect with each other.

The embodiment according to Fig. 2 essentially corresponds to the embodiment according to Fig. 1 , so as to avoid Repetitions below essentially only addresses the differences between the exemplary embodiments. With regard to the similarities between the embodiments is on Fig. 1 with associated figure description referenced.

In contrast to the embodiment according to Fig. 1 the two axial sections 9, 10 are not completely separated magnetically, but next to the material region 11 is provided in the sectional view web-like connecting portion 25 radially inwardly, which is substantially annular and is arranged directly radially adjacent to the material region 11. The radial extension, ie thickness extension of the connecting portion 25 is dimensioned so that upon energization of the coil winding 8 in the connecting portion 25, a magnetic saturation is achieved quickly, so that a resulting loss is minimized. The main river runs like in Fig. 1 located.

The embodiment can be manufactured according to Fig. 2 in that a free space in the form of the present material region 11, for example by machining, is produced in a camshaft body blank and this clearance is then filled with the material forming the material region 11, in particular by build-up welding. Instead of filling the free space 11 with fluid, solidifying material, it is alternatively possible to use a solid ring insert made of non-hard or hardly magnetizable material, for example made of brass and preferably to connect this with two axial sections, for example by friction welding.

The advantage of the second embodiment over the first embodiment is increased mechanical stability. Furthermore, the problem does not arise that an alignment of the two camshaft sections must be ensured separately over the material range.

In all the exemplary embodiments shown, the adjusting partner 5 projects from the outside axially into the camshaft 2 as an example. Particularly preferred is an embodiment (not shown) in which the control partner, in particular a control valve for the camshaft adjustment such as in the EP 2 252 774 B1 shown completely inside the camshaft.

LIST OF REFERENCE NUMBERS

1

camshaft assembly

2

camshaft

3

Phaser

4

actuator

5

actuating partner

6

accommodation space

7

anchor

8th

coil winding

9

axial

10

axial

11

material area

12

magnetic river

13

gap

14

Longitudinal central axis

15

Extensive air gap

16

yoke

17

yoke

18

casing

19

second gap

20

first gap

21

axial stop

22

sleeve section

23

bolt section

24

Bullet

25

connecting portion

Claims (16)

1. A camshaft assembly, comprising a camshaft (2) having in its interior a receiving space (6), at least partially of a magnetisable material for an internal combustion engine and an electromagnetic actuating unit (4) for actuating an actuating partner (5), in particular a control valve of a camshaft adjuster (3), with a coil winding (8) and an armature (7), adjustable by energizing the coil winding (8), for cooperating with the actuating partner (5),
   characterized in that
   the armature (7), at least partially, preferably completely, is arranged inside the camshaft (2) in the receiving space (6) and the coil winding (8) for noncontact adjusting of the armature (7) is arranged radially outside the camshaft (2), and that the camshaft (2) has a first axial section (9) and a second axial section (10), between which a material region (11) influencing the magnetic flux (12) is provided, in order to increase the magnetic flux (12) from one of the axial sections (9, 10) to the respectively other axial section (9, 10) via the armature (7).
2. The camshaft assembly according to Claim 1, characterized in that the material region (11) is constructed from a material which is not magnetisable or is at least more difficult to magnetise than the magnetisable camshaft material.
3. The camshaft assembly according to one of Claims 1 or 2, characterized in that the first and the second axial section (9, 10) are connected securely with one another mechanically via the material region (11).
4. The camshaft assembly according to one of the preceding claims, characterized in that the first axial section (9) and the second axial section (10) are connected in a materially connected manner via the material region (11).
5. The camshaft assembly according to one of the preceding claims, characterized in that the material region (11) is obtained by a microstructural transformation, for example by a partial heat treatment of the camshaft (2).
6. The camshaft assembly according to one of the preceding claims, characterized in that the material region (11) is obtained by filling, in particular by build-up welding, of a free space between the first and the second axial section (9, 10) with material, in particular in the heated, preferably fluid, state, or by the provision, preferably fixing, of a separate annular element.
7. The camshaft assembly according to one of the preceding claims, characterized in that the first axial section (9) and the second axial section (10) are held against one another exclusively via the material region (11), or that the first axial section (9) and the second axial section (10) in a section adjacent to the material region (11) are connected via a connecting section (25), preferably constructed as an annular section, or respectively are constructed in one piece, which connecting section consists of the material of the first and second axial section (9, 10).
8. The camshaft assembly according to one of the preceding claims, characterized in that the material region (11) is circumferentially closed.
9. The camshaft assembly according to one of the preceding claims, characterized in that the coil winding (8) surrounds the camshaft (2) and is arranged coaxially to the camshaft (2) and to the armature (7), or that the coil winding (8) is arranged adjacent to the camshaft (2), preferably such that a coil winding axis runs parallel to the camshaft (2).
10. The camshaft assembly according to one of the preceding claims, characterized in that the armature (7) is received over the majority of its axial extent, preferably completely, in the camshaft (2) and/or that actuating partner (5) is received at least partially in the camshaft (2), preferably extends axially into the latter.
11. The camshaft assembly according to one of the preceding claims, characterized in that the axial extent of the material region (11) is different over its radial extent, preferably that the axial extent decreases with a radial distance from the armature (7) becoming less.
12. A method for the production of a camshaft assembly according to one of the preceding claims,
    characterized in that
    between a first axial section (9) and a second axial section (10) of a camshaft (2) a material region (11), influencing the magnetic flux (12), is provided, in order to increase a magnetic flux (12) from one of the axial sections (9, 10) to the respectively other axial section (9, 10) via an armature (7) which is able to be received in the camshaft (2).
13. The method according to Claim 12, characterized in that the material region (11) is obtained by a microstructural transformation, for example by a partial heat treatment of the camshaft (2).
14. The method according to one of Claims 12 or 13, characterized in that the material region (11) is obtained by filling, in particular by build-up welding, of a free space between the first and the second axial section (9, 10) with material, in particular in the heated, preferably fluid, state.
15. The method according to Claim 14, characterized in that the production of the free space takes place in the same clamping as the filling of the free space.
16. An engine block with a camshaft assembly according to one of Claims 1 to 11, wherein preferably the camshaft (2) and/or the armature (7) and/or the coil winding (8) is/are arranged inside the engine block.

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