DE102018115167B4 - Camshaft adjustment device with a compact structure for a dry belt drive of an internal combustion engine and assembly method of the camshaft adjustment device - Google Patents

Abstract

A camshaft adjusting device (1) is proposed with a camshaft (2) and a hydraulic camshaft adjuster (3) and a central valve (4) arranged coaxially thereto, wherein the central valve (4) projects into the hydraulic camshaft adjuster (3) and into the camshaft (2) and the central valve (4) has two axially adjacent connections (5, 6) to the hydraulic working chambers (7, 8) of the hydraulic camshaft adjuster (3), characterized in that one of the connections (5, 6) is arranged within the camshaft (2) and the other connection (5, 6) is arranged within the hydraulic camshaft adjuster (3), wherein the camshaft (2) has a web (9) in the area between the connections (5, 6), which hydraulically separates the two connections (5, 6) from one another. A method for assembling a camshaft adjusting device (1) is also proposed.

Description

Field of the invention

The invention relates to a camshaft adjusting device with a compact design for a dry belt drive of an internal combustion engine and an assembly method of the camshaft adjusting device.

Background of the invention

Camshaft adjusters are used in combustion engines to vary the timing of the combustion chamber valves in order to be able to make the phase relationship between a crankshaft and a camshaft variable within a defined angular range, between a maximum advanced and a maximum retarded position. Adapting the timing to the current load and speed reduces consumption and emissions. For this purpose, camshaft adjusters are integrated into a drive train, via which torque is transferred from the crankshaft to the camshaft. This drive train can be designed as a belt, chain or gear drive, for example.

In a hydraulic camshaft adjuster, the output element and the drive element form one or more pairs of pressure chambers that act against each other and can be pressurized with hydraulic fluid. The drive element and the output element are arranged coaxially. By filling and emptying individual pressure chambers, a relative movement is generated between the drive element and the output element. The spring that acts in a rotational manner between the drive element and the output element pushes the drive element in a direction of advantage relative to the output element. This direction of advantage can be parallel to or opposite to the direction of rotation.

One type of hydraulic camshaft adjuster is the vane cell adjuster. The vane cell adjuster has a stator, a rotor and a drive wheel with external teeth. The rotor is designed as an output element that can usually be connected to the camshaft in a rotationally fixed manner. The drive element contains the stator and the drive wheel. The stator and the drive wheel are connected to one another in a rotationally fixed manner or, alternatively, are designed as one piece. The rotor is coaxial with the stator and arranged inside the stator. The rotor and the stator form opposing oil chambers with their radially extending vanes, which can be pressurized with oil pressure and enable relative rotation between the stator and the rotor. The vanes are either designed as one piece with the rotor or stator or are arranged as "inserted vanes" in grooves provided for this purpose in the rotor or stator. The vane cell adjusters also have various sealing covers. The stator and the sealing covers are secured to one another using several screw connections.

Another type of hydraulic camshaft adjuster is the axial piston adjuster. Here, a sliding element is moved axially using oil pressure, which generates a relative rotation between a drive element and an output element via helical gears.

Another type of camshaft adjuster is the electromechanical camshaft adjuster, which has a three-shaft gear (for example a planetary gear or a wave gear). One of the shafts forms the drive element and a second shaft the output element. Rotational energy can be supplied to the system or removed from the system via the third shaft using an adjusting device, for example an electric motor or a brake, in order to initiate an adjustment. A spring can also be arranged which supports or reverses the relative rotation between the drive element and the output element.

The US 8 991 346 B2 shows a valve timing control device that controls an opening timing and a closing timing of a valve of an intake valve and an exhaust valve of an internal combustion engine that is opened and closed by an output side shaft of the internal combustion engine by changing a rotational phase between a drive side shaft of the internal combustion engine and the output side shaft. The valve timing control device includes a housing that is integrally rotatable with the drive side shaft and a vane rotor that is rotatable relative to the housing and fixed to the output side shaft. Further, a hydraulic pressure control valve is disclosed that includes a sleeve that is received in a center hole of the vane rotor and extends in a direction of a rotation axis of the vane rotor and a piston that is received in an interior of the sleeve and can reciprocate along the sleeve, the hydraulic pressure control valve changing a hydraulic pressure supplied to or discharged from the advance chamber or the retard chamber by a movement of the piston. A solenoid is disclosed which has a solenoid main body disposed opposite to the housing and a pressing pin protruding from the solenoid main body and configured to press the piston of the hydraulic pressure control valve, the solenoid Changing the hydraulic pressures at the hydraulic pressure control valve. The apparatus further comprises a first tubular portion extending from the housing toward the solenoid and a second tubular portion extending from the solenoid main body or from a mounting member to which the solenoid main body is mounted toward the housing, the second tubular portion cooperating with the first tubular portion to form an oil receiving chamber configured to receive at least one of the following oils: oil discharged from a gap between the housing and the vane rotor; and oil discharged from an oil passage connected to the advance chamber or the retard chamber.

The tubular sections are in sliding contact with each other. The relative rotation of the two tubular sections to each other leads to friction and heating, which leads to the failure of the shaft seal.

The EP 2 927 440 A1 shows an internal combustion engine with a crankshaft rotatable about a crankshaft axis and a camshaft rotatable by the crankshaft about a camshaft axis, the internal combustion engine having an oil supply, an engine cover, a drive member disposed in the engine cover to transmit rotary motion from the crankshaft to the camshaft, and a camshaft adjuster disposed within the engine cover to controllably vary the phase relationship between the crankshaft and the camshaft. The camshaft adjuster has an input member driven by the drive member, an output member rotatable with the camshaft, the output member rotatable relative to the input member by oil from the oil supply, thereby varying the phase relationship between the crankshaft and the camshaft, a valve spool within the camshaft adjuster, an actuator for moving the valve spool, and a seal arrangement defining a dry zone with one of the engine cover and the actuator to isolate the drive member from the oil used.

The central magnet and the shaft seal are fixed to the engine cover during assembly. Because the shaft seal is covered by the central magnet, assembly cannot be carried out visually. The engine cover with the central magnet and the shaft seal must be pushed blindly onto the sealing collar of the adjuster. This results in damage to the shaft seal during assembly. It is not possible to adjust the concentricity of the shaft seal to the sealing collar on the adjuster here; instead, the shaft seal between the central magnet and the camshaft adjuster must absorb all concentricity errors, which reduces the reliability of the seal during operation. In addition, the actuating pin of the central magnet hits the central valve at an indeterminate position, which changes constantly during operation. This can lead to wear and tear and thus also to failure of the control of the camshaft adjuster.

The EN 10 2014 222 589 A1 shows a hydraulic camshaft adjuster for an internal combustion engine, with a stator, with a rotor arranged in the radial direction within the stator and rotatable relative to the stator, wherein a plurality of hydraulic chambers to which pressure medium can be applied are formed between the stator and the rotor, and with a hydraulic central valve for controlling pressure medium application to the hydraulic chambers, with a pressure transmission component which is provided for transmitting a force of an electromagnetic actuator for the purpose of adjusting the central valve, wherein the camshaft adjuster has an adjuster cover attached to the stator with a central opening through which the central valve can be actuated from outside the adjuster cover, wherein a sealing element is arranged on the pressure transmission component and the adjuster cover so as to seal the central opening.

In this arrangement, a connection of the central valve is arranged with regard to its axial position in the joint between the rotor and the camshaft.

Further camshaft adjustment devices are being produced EN 10 2013 209 865 A1 , WO 2015/ 029 476 A1 and US 2010 / 0 175 651 A1 out.

Summary of the invention

The object of the invention is to provide a camshaft adjustment device which has a particularly compact design.

According to the invention, this object is achieved by a camshaft adjusting device having the features of claim 1 and by a method according to claim 5.

For example, a camshaft adjustment device with a camshaft and a hydraulic camshaft adjuster as well as a central valve arranged coaxially to the latter, whereby the central valve protrudes into the hydraulic camshaft adjuster and the camshaft and the central valve has two axially adjacent connections to the hydraulic working chambers of the hydraulic hydraulic camshaft adjuster, this task is achieved in that one of the connections is arranged within the camshaft and the other connection within the hydraulic camshaft adjuster, the camshaft having a web in the area between the connections which hydraulically separates the two connections from one another.

This ensures that the central magnet can be axially displaced into the hydraulic camshaft adjuster as far as possible by axially displacing at least one connection of the central valve into the camshaft, whereby the hydraulic camshaft adjuster is centered relative to the camshaft, which relieves a seal between the hydraulic camshaft adjuster and a central magnet.

Optionally, several connections of the central valve can be moved into the camshaft. In extreme cases, all connections are countersunk in the camshaft, so that the rotor only extends around the section of a screw head of a central screw that supports the central valve or is axially connected to the central valve and is axially preloaded towards the camshaft, with the oil supply to the hydraulic camshaft adjuster coming from the connections arranged inside the camshaft.

Preferably, the central valve is accommodated by a central screw, which can have these connections so that the hydraulic fluid from the central valve can pass through the connections to the working channel(s). In this case, the expert speaks of a central valve screw.

The outer diameter of the central magnet is designed to be radially spaced from the inner diameter of the sealing collar on the hydraulic camshaft adjuster, so that there is no direct contact between the sealing collar and the central magnet. The central magnet can be designed to be nested with the hydraulic camshaft adjuster, whereby a shaft seal can be arranged on an outer surface of the sealing cover surrounding the central magnet between the sealing cover and a timing drive cover. This eliminates the influence of the installation of the central magnet on the concentricity error and on the shaft seal.

The web of the camshaft rests on a web of the output element of the hydraulic camshaft adjuster, which also hydraulically separates the two connections from each other.

The web on the camshaft side is pierced by a slot that opens into a working channel of the camshaft adjuster.

In a particularly preferred embodiment, the camshaft-side web centers the central valve relative to the camshaft axis of rotation. According to the above statements, as an alternative to the central valve, a central screw or a central valve screw can be centered relative to the camshaft axis of rotation via the camshaft-side web. The camshaft-side web is in direct contact with a complementary lateral surface or several lateral surface pieces of the central valve, the central screw or the central valve screw distributed around the circumference. Ideally, three lateral surface pieces distributed around the circumference would be sufficient for effective centering. The lateral surface pieces can also have an axial offset, as long as the centering function is fulfilled.

In one embodiment of the invention, the web on the output element side centers the central valve to the camshaft adjuster rotation axis. The hydraulic camshaft adjuster can thus be centered to the camshaft via the outer diameter of the central valve, or alternatively via the outer diameter of the central screw or the central valve screw. A camshaft adjuster usually has an output element that can be connected to the camshaft and which can assume a relative angular position to a drive element that is connected to the timing drive in a rotationally fixed manner so that the camshaft adjuster can vary the phase position between the camshaft and the crankshaft in order to achieve the desired combustion and consumption effects of the internal combustion engine. The web on the output element side is in direct contact with a complementary lateral surface or several lateral surface pieces of the central valve, the central screw or the central valve screw that are distributed around the circumference. Ideally, three lateral surface pieces that are distributed around the circumference would be sufficient for effective centering. The lateral surface pieces can also have an axial offset so that the centering function is fulfilled.

In a preferred embodiment, a central magnet that actuates the central valve can be aligned coaxially to the central valve, in which the central magnet can be accommodated by a cover element of the hydraulic camshaft adjuster. During its assembly, the central magnet is guided by the inner surface of the cover element into its coaxial position relative to the axis of rotation of the camshaft adjuster or the camshaft with very little positioned with a small position tolerance and centered on one of these axes. This reduces wear between the actuating pin of the central magnet, which contacts and actuates the central valve.

The object is also achieved by a method according to the invention for assembling the camshaft adjustment device, in which the centering of the components according to the invention leads to increased reliability.

• • Fügen des hydraulischen Nockenwellenverstellers mit dem Nockenwellenende der Nockenwelle. Vorteilhafterweise weist der hydraulische Nockenwellenversteller hierfür einen einen Dichtkragen aufweisenden Dichtdeckel auf, welcher auf der nockenwellenzugewandten Seite des hydraulischen Nockenwellenverstellers angeordnet ist und dessen Innenmantelfläche die Nockenwelle umragt. Somit bleibt der hydraulische Nockenwellenversteller nach dem Fügen mit dem Nockenwellenende durch den unzentrierten Kontakt der Innenmantelfläche des Dichtkragens mit der Außenmantelfläche des Nockenwellenendes hängen.
• • Auflegen des Riemens auf den hydraulischen Nockenwellenversteller, insbesondere einer riemenkomplementären Verzahnung,
• • Einstecken eines Zentrierdorns durch den hydraulischen Nockenwellenversteller hindurch und in die Nockenwelle, wobei der Zentrierdorn Kontakt mit einer Zentrierfläche am Innendurchmesser des hydraulischen Nockenwellenverstellers und mit einer Zentrierfläche am Innendurchmesser des Nockenwellenendes hat,
• • Fügen eines Halters, welcher einen Zentralmagnet tragen kann und bereits einen Wellendichtring trägt, wobei der Wellendichtring in Kontakt mit dem Dichtkragen eines auf der nockenwellenabgewandten Seite des hydraulischen Nockenwellenverstellers angeordneten Dichtdeckels kommt. Vorteilhafterweise erfolgt auf diese Weise eine beschädigungsfreie Montage des Wellendichtringes und bereits während der Montage eine Trennung zwischen dem Trockenraum (in dem der Riemen angeordnet ist) und dem (zukünftigen) Nassraum zwischen dem Zentralmagnet und dem hydraulischen Nockenwellenversteller.
• • Befestigen des Halters mit der Brennkraftmaschine,
• • Entfernen des Zentrierdorns. Vorteilhafterweise wird bereits jetzt der hydraulische Nockenwellenversteller durch den Wellendichtring der Nockenwelle in der Position gehalten.
• • Das Zentralventil mit einer das Zentralventil aufnehmenden Zentralschraube durch den hydraulischen Nockenwellenversteller hindurch stecken und in die Nockenwelle einfügen,
• • Anschrauben der Zentralschraube mit einem Drehmoment kleiner als das zu erreichende Vorspannmoment.
• • Den Riemen spannen,
• • Die Zentralschraube mit dem Vorspannmoment anziehen, um eine drehfeste Verbindung zwischen dem hydraulischen Nockenwellenversteller und der Nockenwelle sicherzustellen,
• • Den Zentralmagneten in den Halter fügen und mit dem Halter verliersicher verbinden.

The assembly of the camshaft adjustment device comprises the following steps, which are advantageously carried out in the order mentioned:

• • Joining the hydraulic camshaft adjuster to the camshaft end of the camshaft. The hydraulic camshaft adjuster advantageously has a sealing cover with a sealing collar, which is arranged on the side of the hydraulic camshaft adjuster facing the camshaft and whose inner surface extends around the camshaft. Thus, after joining the camshaft end, the hydraulic camshaft adjuster gets stuck due to the uncentered contact of the inner surface of the sealing collar with the outer surface of the camshaft end.
• • Placing the belt on the hydraulic camshaft adjuster, in particular a belt-complementary toothing,
• • Inserting a centering pin through the hydraulic camshaft adjuster and into the camshaft, whereby the centering pin is in contact with a centering surface on the inner diameter of the hydraulic camshaft adjuster and with a centering surface on the inner diameter of the camshaft end,
• • Joining a holder which can carry a central magnet and already carries a shaft seal, whereby the shaft seal comes into contact with the sealing collar of a sealing cover arranged on the side of the hydraulic camshaft adjuster facing away from the camshaft. This advantageously allows the shaft seal to be installed without causing damage and, during installation, a separation is created between the dry space (in which the belt is arranged) and the (future) wet space between the central magnet and the hydraulic camshaft adjuster.
• • Attaching the holder to the engine,
• • Remove the centering mandrel. The hydraulic camshaft adjuster is advantageously already held in position by the camshaft shaft seal.
• • Insert the central valve with a central screw that holds the central valve through the hydraulic camshaft adjuster and insert it into the camshaft,
• • Screw the central screw with a torque less than the preload torque to be achieved.
• • Tighten the belt,
• • Tighten the central screw to the preload torque to ensure a torque-proof connection between the hydraulic camshaft adjuster and the camshaft,
• • Insert the central magnet into the holder and securely connect it to the holder.

It is possible that the method steps can be interchanged as long as the components mentioned and their purpose are taken into account in the sense of the described invention.

• • Das Zentralventil mit einer das Zentralventil aufnehmenden Zentralschraube durch den hydraulischen Nockenwellenversteller hindurch stecken und in die Nockenwelle einfügen,

kann das Zentralventil von der Zentralschraube getrennt montiert werden sein. So kann beispielsweise zuerst der Nockenwellenversteller an der Nockenwelle mit einer Zentralschraube befestigt werden und in einem nachgelagerten Schritt das Zentralventil in die Zentralschraube montiert werden.Alternatively to step:

• • Insert the central valve with a central screw that holds the central valve through the hydraulic camshaft adjuster and insert it into the camshaft,

The central valve can be mounted separately from the central screw. For example, the camshaft adjuster can first be attached to the camshaft with a central screw and the central valve can then be mounted in the central screw in a subsequent step.

In one embodiment of this variant, the central valve can be arranged axially consecutively to the central screw, so that the central valve is, for example, directly received by the camshaft adjuster.

The fastening function of the central screw can be replaced or supplemented by an alternative fastening option. The camshaft adjuster can be attached to the camshaft, for example by welding, which eliminates the screwing steps. The central valve can still be inserted into the camshaft adjuster and/or the camshaft and securely fastened to the camshaft adjuster and/or the camshaft.

The hydraulic camshaft adjuster, the central valve and also the holder with the shaft seal are positioned particularly precisely to the axis of rotation of the camshaft during assembly and aligned. Due to this resulting short tolerance chain, the concentricity error between the aforementioned elements and the camshaft is particularly low.

• - die Nockenwellenverstellvorrichtung für den trockenen Zahnriementrieb ist axial besonders bauraumsparend ausgebildet
• - die Nockenwellenverstellvorrichtung hat einen besonders kleinen Rundlauffehler zwischen dem Wellendichtring, dem Nockenwellenversteller und dem Zentralventil durch die erfindungsgemäße Zentrierung über die vorstehend beschriebenen strukturellen Zentrierelemente
• - eine sichere Montage des Wellendichtrings ohne Beschädigung seiner Dichtlippe und eine erhöhte Lebensdauer desselben
• - eine einfache Zentralmagnetmontage
• - eine einfachere Montage der Nockenwellenverstellvorrichtung durch einen Zentrierdorn.

The solution according to the invention therefore has the following advantages:

• - the camshaft adjustment device for the dry toothed belt drive is designed to save axial space
• - the camshaft adjustment device has a particularly small concentricity error between the shaft seal, the camshaft adjuster and the central valve due to the centering according to the invention via the structural centering elements described above
• - safe installation of the shaft seal without damaging its sealing lip and an increased service life of the same
• - a simple central magnet mounting
• - easier installation of the camshaft adjustment device using a centering mandrel.

Short description of the drawings

Embodiments of the invention are shown in the figures.

• 1 die erfindungsgemäße Nockenwellenverstellvorrichtung,
• 2 die Montage der Nockenwellenverstellvorrichtung nach 1 mit einer ersten Variante eine Zentrierdorns und
• 3 die Montage der Nockenwellenverstellvorrichtung nach 1 mit einer zweiten Variante des Zentrierdorns.

It illustrates:

• 1 the camshaft adjustment device according to the invention,
• 2 the assembly of the camshaft adjustment device according to 1 with a first variant of a centering mandrel and
• 3 the assembly of the camshaft adjustment device according to 1 with a second variant of the centering mandrel.

Detailed description of the drawings

1 shows the camshaft adjusting device 1 according to the invention. The camshaft adjusting device 1 has a camshaft adjuster 3. The structure and function of the camshaft adjuster 3 is largely known from the prior art. However, the camshaft adjuster 3 differs from those from the prior art in that it has a web 10 on the output element side and in its small axial installation space resulting from the invention shown here. The web 10 rests against a web 9 on the camshaft side. The web 9 and/or the web 10 is in contact with the outer peripheral surface of a central screw 25 carrying the central valve 4. The central valve 4 has, with the central screw 25, several connections 5 and 6 that can supply or discharge hydraulic fluid to the working chambers 7, 8. The connections 5 and 6 are arranged at a distance in the axial direction and flank the webs 9 and 10. The centering effect of the webs 9 and 10 also seals the connections 5 and 6 against each other. However, so that the hydraulic fluid from the connection 5, which is arranged inside the camshaft 2 in order to shorten the axial installation space, can reach the camshaft adjuster 3, the web 9 is penetrated by at least one slot 11. The slot 11 is machined into the camshaft end as a notch. This can be arranged in one of its plurality as a regular or irregular pattern over the circumference of the web 9, and thus also around the axis of rotation 14 or 15.

The other connection 6 is arranged inside the camshaft adjuster 3 and supplies the working chamber 8 with hydraulic fluid via the working channel 13. The hydraulic fluid from the connection 5 flows via the slot 11 into the working channel 12 and finally into the working chamber 7, which acts in the opposite direction to the working chamber 8.

2 shows the assembly of the camshaft adjustment device 1 after 1 with a first variant of a centering mandrel 18. The centering mandrel 18 simulates the central screw 25, which will replace the centering mandrel 18 in a later assembly step, and engages in the thread of the camshaft 2 provided for the central screw 25. The centering mandrel 18 thus aligns the camshaft adjuster rotation axis 15 to the camshaft rotation axis 14 of the camshaft 2 via its outer surface in contact with the webs 9 and 10 or with the centering surfaces 19, 20. At the same time, the centering mandrel 18 can also align the holder 21 to the camshaft 2 and/or to the camshaft adjuster 3 so that a central magnet 16 later mounted on the holder 21 is aligned coaxially with its axis of symmetry to one of the axes 14, 15 or to both, so that an actuating pin actuating the central valve 4 acts as centrally as possible and thus wear occurring due to relative movement at the contact point or a tilting effect on the control piston of the central valve 4 is minimized.

A seal designed as a shaft seal 22, which has already been mounted with the holder 21, is also aligned with the camshaft adjuster 3 and thus also with the cover element 17, so that the sealing collar 23 of the cover element 17 designed as a sealing cover 24, which is in contact with the shaft seal 22, has a slight misalignment when the sealing collar 23 later rotates relative to the shaft seal 22 during operation. This also ensures the tightness at this point. between a wet room and a dry room - in which the timing belt is located - is improved.

3 shows the assembly of the camshaft adjustment device 1 after 1 with a second variant of the centering mandrel 18. The centering mandrel 18 according to 3 differs from that according to 2 in that it no longer engages in the thread of the camshaft 2, but in a fitting surface formed by the camshaft 2. However, this can be omitted in this embodiment, provided that reference is made to the centering surface 20 of the web 9.

List of reference numbers

1)

Camshaft adjustment device

2)

camshaft

3)

Camshaft adjuster

4)

Central valve

5)

Connection

6)

Connection

7)

Chamber of Labor

8th)

Chamber of Labor

9)

camshaft side web

10)

web

11)

slot

12)

Working channel

13)

Working channel

14)

Camshaft rotation axis

15)

Camshaft adjuster rotation axis

16)

Central magnet

17)

Cover element

18)

Centering mandrel

19)

Centering surface (camshaft adjuster)

20)

Centering surface (camshaft)

21)

holder

22)

Shaft seal

23)

Sealing collar

24)

Sealing cover

25)

Central screw

Claims (5)

Camshaft adjustment device (1) with - a camshaft (2) rotatable about a camshaft rotation axis (14), - a hydraulic camshaft adjuster (3) which has two hydraulic working chambers (7, 8) and an output element, and - a central valve (4) which is arranged coaxially to the camshaft adjuster (3), projects into the latter and into the camshaft (2) and which has two axially adjacent connections (5, 6) to the hydraulic working chambers (7, 8), wherein one of the connections (5, 6) is arranged within the camshaft (2) and the other of the connections (6, 5) is arranged within the camshaft adjuster (3), wherein the camshaft (2) has a camshaft-side web (9) in the area between the connections (5, 6), which hydraulically separates the two connections (5, 6) from one another, wherein the camshaft-side web (9) is attached to a web (10) of the Output element, which also hydraulically separates the two connections (5, 6) from one another, characterized in that the camshaft-side web (9) is pierced by a slot (11) which opens into a working channel (12, 13) of the camshaft adjuster (3). Camshaft adjustment device (1) according to Claim 1 , characterized in that the camshaft-side web (9) centers the central valve (4) to the camshaft rotation axis (14). Camshaft adjusting device (1) according to one of the preceding claims, characterized in that the web (10) of the output element centers the central valve (4) to a camshaft adjuster rotation axis (15). Camshaft adjusting device (1) according to one of the preceding claims, characterized in that a central magnet (16) actuating the central valve (4) can be aligned coaxially to the central valve (4) in that the central magnet (16) can be received by a cover element (17) of the camshaft adjuster (3). Method for assembling a camshaft adjustment device (1) according to Claim 4 , which comprises the following steps: • Joining the hydraulic camshaft adjuster (3) to a camshaft end of the camshaft (2), • Placing a belt on the camshaft adjuster (3), • Inserting a centering mandrel (18) through the camshaft adjuster (3) and into the camshaft (2), wherein the centering mandrel (18) has contact with a centering surface (19) on the inner diameter of the camshaft adjuster (3) and with a centering surface (20) on the inner diameter of the camshaft end, • Joining a holder (21) which can carry the central magnet (16) and already has a shaft seal ring (22), the shaft sealing ring (22) coming into contact with a sealing collar (23) of a sealing cover (24) arranged on the side of the camshaft adjuster (3) facing away from the camshaft, • fastening the holder (21) to an internal combustion engine, • removing the centering mandrel (18), • pushing the central valve (4) with a central screw (25) receiving the central valve (4) through the camshaft adjuster (3) and inserting it into the camshaft (2), • screwing on the central screw (25) with a torque less than a preload torque to be achieved, • tensioning the belt, • tightening the central screw (25) with the preload torque to ensure a rotationally fixed connection between the camshaft adjuster (3) and the camshaft (2), • inserting the central magnet (16) into the holder (21) and connecting it to the holder (21) in a captive manner.

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