EP1776513B1 - Electromotive camshaft adjuster - Google Patents

Description

Field of the invention

The invention relates to an electromotive camshaft adjuster for adjusting the rotational angle of the camshaft of an internal combustion engine with respect to its crankshaft, in particular according to the preamble of patent claim 1.

Background of the invention

Electromotive camshaft adjusters are characterized by fast and exact camshaft adjustment in the entire operating range of the internal combustion engine. This also applies to the cold start and the restart after stalling the internal combustion engine.

Electric camshaft adjusters consist of an adjusting mechanism rotatably connected to the camshaft and an electromotive adjusting drive fastened to the internal combustion engine, whose motor shaft engages the adjusting shaft of the adjusting mechanism revolving with camshaft rotational speed.

As adjusting mechanism, the following three-shaft transmissions are mostly used:

- Swashplate transmission.

Such a camshaft adjuster is from the US 2002/0017257 known. The phaser has a first bevel gear connected to the camshaft, a second bevel gear driven by the crankshaft, and a swash plate. The swash plate has two annular teeth, wherein one of the teeth engages in a toothing of the first and the other teeth in a toothing of the second bevel gear. These swash plate gears have a simple structure. However, their manufacturability in mass production is not clear. In addition, they are susceptible to tolerances and the production of the gear parts is associated with high costs, since they have to be machined due to high stress and accuracy reasons.

- Double inner eccentric gear.

This type of transmission is very functional and smooth, but causes a considerable cost because of the large number of components.

- Planetary and cycloidal gears (so-called harmonic drive gears).

Such a transmission is in the DE 40 227 35 A1 in which an electromotive camshaft adjuster for the rotational angle adjustment of the camshaft of an internal combustion engine relative to the crankshaft thereof is disclosed, with a three-shaft gear having a crankshaft fixed, formed as a chain or toothed belt drive wheel and a camshaft fixed output member and an adjusting shaft which is connected to the rotor of an electric Adjusting motor rotatably connected and whose stator is fixed to the engine.

This cycloidal gear is characterized by small space and great reliability, but requires a lot of construction.

From the US 6,517,772 B1 , of the WO 2002/031374 A and the JP 2000-129312 A are known methods for manufacturing sintered gears.

Object of the invention

The invention is therefore an object of the invention to provide a three-shaft transmission for an electric motor driven camshaft adjuster, which requires a relatively low production cost.

Summary of the invention

The object is achieved in that the hollow and spur gears are designed as internally or externally toothed toothed rings, which are separated by internally or externally profiled tubes in the required length. Thus, lower production costs can be achieved. For example, the profiled tubes may be drawn or extruded or sintered.

In an alternative embodiment of the invention, the object is achieved in that the hollow and spur gears from tooth-profiled tapes formed into toothed rings, closed by welding or clipping and then recalibrated, whereby the cost can be reduced.

In a further alternative embodiment of the invention, the object is achieved in that the single inner eccentric gear instead of a camshaft torque transmitting hollow / Stirnradpaares has a so-called Kugelorbitalkupplung, in which balls, the half-side in circulation paths of two equal, under axial prestressing steel discs out are, the torque transmitted backlash and compensate for the eccentric movement, wherein one of the steel discs with a spur gear of the transmission and the other with a camshaft fixed part thereof are rotationally connected.

The swashplate and the single internal eccentric gearbox offer various possibilities for reducing the manufacturing effort. Both types of gears can be manufactured largely without cutting. The swash plate mechanism also offers the possibility of a simple backlash compensation, while the single inner eccentric gear has many ways to reduce the number of components.

It is advantageous that brushless DC motors, in particular those with rare-earth magnets and with bipolar operation, are provided as electrical adjustment motors. These motors are characterized by the lack of commutator by simple design, high acceleration and virtually wear-free operation.

An important feature of the quality of a variable speed is the correct backlash of the pairs of teeth. Due to the dynamic camshaft torque, excessive backlash during operation can lead to torsional vibrations between the two bevel gears. This may cause noise or control problems. If the game is too small, the adjusting mechanism jams or has too poor an efficiency. However, backlash can not be avoided.

A limitation of the form tolerances to reach their maximum value by high manufacturing accuracy succeeds only conditionally. For this reason, it makes sense to make the backlash adjustable. The backlash compensation provides that the minimum torsional backlash should result when the upper tolerances of the form tolerances of the components meet. If the dimensions of the components at the lower or between the lower and upper tolerance limit, a theoretical overlapping of the teeth would result.

Cost advantages provides an inner eccentric gear, which is designed as a single inner eccentric gear, in that it has only one inner eccentric for a first and second spur gear, both rotationally connected to each other are and roll on a first and second ring gear. The first end and ring gear are used exclusively for the reduction in the phase adjustment and the second front and ring gear also or even exclusively as a coupling toothing for passing the drive and Verstellieistung to the camshaft.

The second spur gear performs the same eccentric movement as the first, since both are rotatably connected to each other. If the second hollow / spur gear pair has the same number of teeth difference as the first, it serves only as a toothed coupling, which does not contribute to the overall ratio of the variable transmission. But it is also possible to distribute the total translation on both pairs of gears, resulting in greater freedom in the teeth selection.

In principle, it is also conceivable that, as with double Innenexzentergetrieben instead of the gear coupling a claw, segment or pin coupling takes over the coupling function. The simple inner eccentric gear is then easier, but the pins or claws must slide when compensating the eccentric movement in their mating surface. This results in a lower efficiency than with a toothed coupling, in which the second spur gear rolls in the second ring gear with low friction.

To further reduce the friction contributes that the single inner eccentric and the two spur gears and optionally the drive wheel are roller bearings, the latter preferably has a four-point bearing. As a roller bearing ball, roller or needle roller bearings come into question. A four-point bearing is particularly suitable for absorbing tilting moments, as they can occur in the drive wheel. If the bearing friction plays a minor role compared to the construction costs and installation space, all bearings can be replaced by slide bearings if the adjustment shaft is dimensioned accordingly. Manufacturing costs can also be reduced by the fact that the first spur gear is widened by the width of the second spur gear and meshes with both equally toothed ring gears.

A backlash compensation takes place in the single inner eccentric gear in the two front / Hohlradpaaren separately, the backlash compensation in the first end / Hohlradpaar by selecting a matching eccentric and the second end / Hohlradpaar by a corresponding profilverschobenes second end / ring gear or by an additional , From the first eccentric independently adjustable, on the adjusting shaft secured against rotation Ausgleichsexzenter done. A particularly cost-effective form of backlash compensation is that this is done by slightly conical, axially to just before line contact pushed into each other front and ring gears, under preferential utilization of their production-related conicity.

Another cost-effective way to achieve an optimal backlash is that an inlet operation of the adjustment is provided with a mounted on the teeth, relatively soft and lubricious wear layer, for example of copper or plastic, which enters until it reaches a predetermined backlash under bias ,

Instead of backlash compensation tooth noise can also be reduced by helical front and ring gears. By an opposite slope of the teeth of the two front and ring gears cancel their axial forces, thereby simplifying storage.

Similar to the swash plate mechanism and the single inner eccentric gear spring preload of the teeth between the camshaft output and the drive wheel and / or the adjustment for tooth noise reduction is possible.

A production-favorable design of the invention is that the second ring gear with the output flange and optionally with the intermediate piece integrally formed and by, for example, wobble or axial presses, sintering or deep drawing can be produced. In this way, the number of components can be significantly reduced.

It has manufacturing advantages that the eccentric and the adjusting shaft with the gear coupling one or two parts executable. The one-piece design offers the advantage of low component count. It can be realized by sintering, tumbling and deep drawing. The two-part design offers the advantage that the eccentric can be inexpensively manufactured from an eccentric tube into which a toothed clutch disc can be pressed.

A single inner eccentric gear with a small axial length is achieved in that a drive wheel and an output part, a first and a second ring gear and a first and a second spur gear are arranged coaxially, wherein the drive wheel with the first ring gear, the first spur gear through a flange with the second ring gear and the second spur gear are rotationally connected to the output member and the first ring gear with the first spur gear and the second ring gear mesh with the second spur gear.

For certain applications, it may be advantageous that in a single inner eccentric gear, the second ring gear are formed as a second spur gear and the second spur gear as a second ring gear, wherein the second ring gear and the second spur gear mutually engage each other.

It is also conceivable that the front and ring gears of the single inner eccentric gearboxes are replaced by corresponding friction wheels. These are characterized by low noise and wear resistance, but require sufficient contact pressure.

Brief description of the drawings

Figur 1

einen Längsschnitt durch ein Taumelscheibengetriebe;

Figur 2

einen Längsschnitt durch ein Einfach-Innenexzentergetriebe;

Figur 3

eine Ansicht des Einfach-Innenexzentergetriebes von Figur 2;

Figur 4 bis 7

einen Längsschnitt durch konstruktive Varianten des Ein- fach-Innenexzentergetriebes von Figur 2;

Figur 8

einen Querschnitt durch das Einfach-Innenexzentergetriebe von Figur 4, jedoch mit einer einteiligen Ausbildung des zweiten Hohlrades, des Antriebsflansches und des Zwi- schenstücks;

Figur 9

eine Seitenansicht einer Kugelorbitalkupplung;

Figur 10

eine perspektivische Ansicht einer Scheibe der Kugelorbital- kupplung von Figur 9;

Figur 11

einen Querschnitt durch ein Einfach-Innenexzentergetriebe mit koaxialer Anordnung der Zahnräder;

Figur 12

einen Querschnitt durch ein Einfach-Innenexzentergetriebe gemäß Figur 11, jedoch mit vertauschtem zweiten Hohl- und Stirnrad.

Further features of the invention will become apparent from the following description and the drawings, in which an embodiment of the invention is shown schematically. Showing:

FIG. 1

a longitudinal section through a swash plate gear;

FIG. 2

a longitudinal section through a single inner eccentric gear;

FIG. 3

a view of the single-inner eccentric transmission of FIG. 2 ;

FIGS. 4 to 7

a longitudinal section through constructive variants of the single inner eccentric of FIG. 2 ;

FIG. 8

a cross section through the single inner eccentric of FIG. 4 but with a one-piece construction of the second ring gear, the drive flange and the intermediate piece;

FIG. 9

a side view of a Kugelorbitalkupplung;

FIG. 10

a perspective view of a disc of Kugelorbital- coupling of FIG. 9 ;

FIG. 11

a cross section through a single inner eccentric gear with coaxial arrangement of the gears;

FIG. 12

a cross section through a single inner eccentric according to FIG. 11 , but with reversed second hollow and spur gear.

Detailed description of the drawings

In FIG. 1 is a longitudinal section through a swash plate cloth 1 shown. This has a sprocket designed as a drive wheel 2, which is rotatably connected via a chain, not shown, with such a crankshaft of an internal combustion engine and formed integrally with a rotationally symmetrical gear housing 3.

The gear housing 3 has at its free end an outer flange 4 with threaded holes 5, to which a first bevel gear 6 is flanged by means of screws 7. At the drive-wheel-side end of the transmission housing 3, an inner flange 8 is provided, which serves for the radial and axial mounting or fixing the position of the gear housing 3 and the drive wheel 2. The radial bearing of the same takes place on a shoulder 9 of a second bevel gear 10, while its axial positional fixation is effected by a shoulder 11 of the same in connection with a thrust washer 12 which is pressed and / or welded to the drive wheel 2.

The second bevel gear 10 is rotationally connected by a central clamping screw 13 with a camshaft 14. A hollow flange 15 at the free end of the camshaft 14 serves for the axial and radial positional fixing of the second bevel gear 10 and the thrust washer 12.

Between the bevel gears 6, 10 is an inclined, mutually toothed swash plate 16. The inclination of the swash plate 16 is selected so that the teeth of each side thereof is in constant engagement with one of the two bevel gears 6, 10. The swash plate 16 is supported by two designed as a fixed bearing deep groove ball bearings 17 on an adjusting 18, which is in turn mounted with two trained as a floating needle bearings 19 on a cylindrical portion 20 of the second bevel gear 10.

The adjusting shaft 18 is rotationally connected to a non-illustrated rotor of a brushless, reversible DC motor.

The two bevel gears 6, 10 and the swash plate 16 are produced by powder metallurgy. Their teeth are aftertreated to increase the strength with constant part accuracy by, for example, Verzahnungsnachwälzen or hot or high-pressure presses.

The swash plate mechanism 1 is via oil lines 21, which emanate from a camshaft bearing 22 and lead to an annular space 23 and further through, not shown, radial bore to the bearings 19 and 17 and to the teeth. A corresponding design of the first bevel gear 6 ensures a sufficient oil level in the swash plate gear 1 sure.

The backlash can be adjusted in the swash plate mechanism 1 in a simple manner. By a suitable Washer 24 between the outer flange 4 of the gear housing 3 and the first bevel gear 6 can be inserted, the backlash is set to zero. By replacing this washer with a reinforced by the backlash, this is set.

The swash plate transmission 1 works in the following way:

In normal operation, that is, at a constant phase position, the swash plate mechanism 1 including the rotor of the electric adjusting motor, not shown, runs as a whole with camshaft speed. Only for early or late adjustment of the timing accelerates or decelerates the adjusting motor its rotor relative to the camshaft 14. As a result, the adjusting shaft 18 relative to the transmission housing 3 forward or backward rotated, causing the swash plate 16 on the bevel gears 6, 10 corresponding to the small Number of teeth difference between the swash plate and the bevel gears with large reduction rolls and performs the phase adjustment.

FIG. 2 shows a longitudinal section through a single inner eccentric 25 and FIG. 3 a view of the output side of the same.

In longitudinal section of the FIG. 2 is to be recognized as a sprocket formed drive wheel 2a, which is rotationally connected to a first ring gear 26. This connection can be achieved by pressing, in particular after knurling on both sides and / or by laser welding.

The first ring gear 26 meshes with a first spur gear 27 which is rotationally connected to a second spur gear 28 by interference fit. This is mounted on a single inner eccentric 30 via a first needle bearing 29, which is rotatably connected via a toothed coupling 31 in conjunction with a not shown rotor of an electric variable motor. The inner eccentric 30 is mounted via a second needle bearing 32 on an intermediate piece 33 which is clamped by a non-illustrated central clamping screw via a driven flange 34 with the camshaft, also not shown rotationally is. The second spur gear 28 meshes with a second ring gear 35, on the circumference of the first ring gear 26 is slidably mounted with the drive wheel 2a.

The second ring gear 35 is rotationally connected to the camshaft fixed output flange 34. Both are axially against a stop plate 36, which is rotationally connected to the first ring gear 26.

The output flange 34 has, as well as out FIG. 3 It can be seen, a nose 37 which is in a the adjustment of the single inner eccentric gear 25 limiting annular cutout 38 of the stop plate 36 between two stops 39, 40 pivotally. The output flange 34 can be produced without cutting by sintering, tumbling or axial rolling. It can also be sintered together with the second ring gear 35.

On the Verstellmotorseite the single inner eccentric gear 25, a metal cover 41 is provided, which is pressed into a recess 42 and the axial movement of the two spur gears 27, 28 and an adjusting 18 'limited.

The single internal eccentric gear 25 works as follows:

In normal operation, the single inner eccentric gear 25 and the rotor of the variable speed motor as a whole rotate at the camshaft speed. During the early or late adjustment of the camshaft, the adjusting motor accelerates or decelerates the adjusting shaft 18 'with the inner eccentric 30. As a result, the spur gears 27, 28 roll on the ring gears 26, 35 and cause the phase adjustment due to the small number of teeth difference of the associated front / ring gears with big reduction.

FIG. 4 represents a single inner eccentric gear 25 'as a constructive variant of the single inner eccentric 25 of FIG. 2 A drive wheel 2a 'is integrally sintered together with a first ring gear 26' and its teeth. If necessary, the toothing can be rolled in order to achieve increased tooth strength.

A second ring gear 35 'is connected to an output flange 34' by a press fit and by welding. Both components can advantageously also be manufactured in one piece by sintering.

A first spur gear 27 'is extended by the width of a second spur gear 28'. The toothing of the ring gears 26 ', 35', despite different numbers of teeth thanks to profile displacement on the same inner diameter and so makes a combing with the first spur gear 27 'possible. The first spur gear 27 'can be produced by sintering but also by tumbling, cold pressing or extrusion.

The first spur gear 27 'is mounted on a single inner eccentric 30' via a first needle bearing 29 'and on a spacer 33' via a second needle bearing 32 '. This can be manufactured inter alia by sintering, extrusion or deep drawing. Its relative to the intermediate piece 33 reduced outer and inner diameter makes a support of the screw head of the central clamping screw on an end face 43 of the intermediate piece 33 'required. This results in the modified form of an adjustment shaft 18 ", which can be made by extrusion or deep drawing and a gear coupling 31 'by punching.

The sheet metal lid 41 'is also used in this variant as an axial stop for the first spur gear 27' and the adjusting shaft 18 "and as a lubricating oil guide A snap ring 44 serves as an axial stop of the second ring gear 35 'on the output side.

This in FIG. 5 illustrated single inner eccentric gear 25 "differs from the single inner eccentric 25 or 25 'by attaching a stop plate 36' to the first ring gear 26". This takes place tangentially through in slots 45 of the same projecting pin 46 of the stop plate 36 ', while as axial securing a snap ring 44' is used.

Another difference lies in a two-part single inner eccentric 30 ", which can be cut off by a correspondingly shaped, extruded tube and which can be pressed and welded with a punched tooth coupling 31".

In a sintered output flange 34 ", a radially extending lubricating oil channel 47 is impressed, which supplies the needle bearings 32", 29 "and the toothings of the end and ring gears 27", 28 ", 26", 35 "with lubricating oil. , 28 "are one-piece and sintered, including their gears.

• ein einteiliges Antriebsrad 2a"/erstes Hohlrad 26'" ist aufgrund seiner Abmessungen als Taumelpressteil geeignet;
• eine tiefgezogene Anlaufscheibe 36" ist mit dem Antriebsrad 2a" durch Presssitz und Laserschweißen verdrehfest verbunden. Sie dient mit ihrem Innenumfang als Gleitlager für das Antriebsrad 2a" und für das erste Hohlrad 26'" und zudem als Axialanschlag für ein zweites Hohlrad 35"' und den mit ihm verbundenen Abtriebsflansch 34"'.

A single-internal eccentric gear 25 '"after FIG. 6 differs from the previous variants by the following features:

• a one-piece drive wheel 2a "/ first ring gear 26 '" is suitable due to its dimensions as a wobble pressing part;
• a deep-drawn thrust washer 36 "is rotationally connected to the drive wheel 2a" by press fit and laser welding. It serves with its inner circumference as a sliding bearing for the drive wheel 2a "and for the first ring gear 26 '" and also as an axial stop for a second ring gear 35 "' and the driven flange 34"'connected thereto.

This in FIG. 7 shown single inner eccentric gear 25 "" is characterized by a first end and ring gear 27 "", 26 "" with a rectangular cross section. These rings are particularly suitable for cutting to length of a corresponding internally or externally toothed tube. The same applies to the first spur gear 27 of FIG. 2 and the first spur gear 27 '"of FIG. 6 ,

The first ring gear 26 '"is pressed into the drive wheel 2a'', while a second ring gear 35''in the drive wheel 2a''slidably mounted and axially guided by a welded to the same thrust washer 36'.

In FIG. 8 is the single-internal eccentric gear 25 'of FIG. 4 shown in cross-section, but with a one-piece design of the intermediate piece 33 'with the drive flange 34' and the ring gear 35 '. This significantly reduces the number of components. As a manufacturing process, especially sintering comes into question.

FIG. 9 shows a side view of a so-called Kugelorbitalkupplung 49, which, like a claw, segment or pin coupling, serves as a replacement for a ring gear / spur gear coupling to compensate for the eccentric movement. The ball orbital coupling 49 has two steel discs 50, between which balls 51 are clamped under axial prestressing. The balls 51 are half-side in circulation paths 52 of the steel discs 50 out (see also FIG. 10 ), where they perform a circular motion without needing to play. One of the steel discs 50 is rotationally connected to one of the spur gears of the single inner eccentric gear, the other with a camshaft fixed part of the transmission.

FIG. 11 illustrates a single-internal eccentric 25 ""', which is rotationally connected via an elastomeric clutch 48 with a camshaft, not shown. A special feature of this transmission is the coaxial arrangement of a first and second ring gear 26 ""', 35 ""' and a first and second spur gear 27 ""', 28 "' The first ring gear 26 ""'to a double deep groove ball bearing 53, which receives the tilting moment of the same and the load of a drive wheel 2a "", relatively low. This has a positive effect on the rolling behavior of the teeth because of the smaller radial displacements formed integrally with the first ring gear 26 ""', in the same way the first spur gear 27 ""' and the second ring gear 35 ""', which are interconnected by a flange 54. The second spur gear 28 "' is provided with an output member 55th and an adjusting shaft 18 "" with a single inner eccentric 30 '"in one piece The single inner eccentric 30'" and the first spur gear 27 ""'with the second ring gear 35 ""' are mounted on a second and third double deep groove ball bearings 56, 57.

In FIG. 12 the cross section of a single internal eccentric gear 25 """is shown, which differs from that of FIG. 11 differs by swapping the local second ring gear and the local second spur gear. These are in FIG. 12 are designed as a new second ring gear 35 "" and a new second spur gear 28 "" and mutually engage in one another.A drive wheel 2a """, a flange 54 'and a driven part 55" are adapted to the changed construction. Inner eccentric gear 25 ""'and 25 """corresponds to that in the FIGS. 2 to 8 illustrated gear.

LIST OF REFERENCE NUMBERS

1

Swash plate mechanism

2, 2a, 2a ', 2a ", 2a"', 2a "", 2a "" '

drive wheel

3

gearbox

4

outer flange

5

threaded hole

6

first bevel gear

7

screw

8th

inner flange

9

paragraph

10

second bevel gear

11

shoulder

12

thrust washer

13, 13 '

central clamping screw

14

camshaft

15

hollow flange

16

swash plate

17

Deep groove ball bearings

18, 18 ', 18 ", 18'", 18 ""

adjusting

19

needle roller bearings

20

cylindrical part

21

oil line

22

camshaft bearings

23

annulus

24

washer

25, 25 ', 25 ", 25"', 25 "", 25 "" ', 25 "" "

Single eccentric internal

26, 26 ', 26 ", 26"', 26 "", 26 "" '

first ring gear

27, 27 ', 27 ", 27'", 27 "", 27 "" '

first spur gear

28, 28 ', 28 ", 28'", 28 ""

second spur gear

29, 29 ', 29 "

first needle bearing

30, 30 ', 30 ", 30"'

Single internal eccentric

31,31 ', 31 "

Tooth shaft coupling

32, 32 ', 32 "

second needle bearing

33, 33 '

connecting piece

34, 34 ', 34 ", 34"'

output flange

35, 35 ', 35 ", 35"', 35 "", 35 "" ', 35 "" "

second ring gear

36.36 ', 36 ", 36"'

stop disc

37

nose

38

ring section

39

first stop

40

second stop

41, 41 '

sheet metal lid

42

written settlement

43

face

44, 44 '

snap ring

45

slot

46

spigot

47

Lubricating oil passage

48

elastomer coupling

49

Ball orbital coupling

50

steel disc

51

Bullet

52

Cycle track

53

first double deep groove ball bearing

54, 54 '

flange

55, 55 '

stripping section

56

second double deep groove ball bearing

57

third double groove ball bearing

58

third spur gear

Claims (3)

1. Electromotive camshaft adjuster for adjusting the angle of rotation of the camshaft (14) of an internal combustion engine relative to the crankshaft of same, with a triple-shaft gear mechanism which has a driving wheel (2, 2a, 2a', 2a", 2a"', 2a"", 2a""') which is driven by the crankshaft, and an output part mounted on the camshaft, and an adjusting shaft (18, 18', 18", 18"', 18"") which is connected in a rotationally fixed manner to a rotor of an electric adjusting motor, the stator of which is fixed on the internal combustion engine, wherein the triple-shaft gear mechanism comprises sets of gears and housing parts produced without cutting and has devices for adjusting and compensating for the backlash, wherein the triple-shaft gear mechanism is designed as a single internaleccentric gear mechanism (25, 25', 25", 25"', 25"", 25""', 25""") with a single internal eccentric (30, 30', 30", 30"') on which a first and second spur gear (27, 27', 27", 27"'; 27"", 27""'; 28, 28', 28", 28"', 28"") are fitted, which spur gears are connected to each other in a rotationally fixed manner and roll along a first and second internal gear (26, 26', 26", 26"', 26"", 26""'; 35, 35', 35", 35"_', 35"", 35""', 35"""), wherein the first spur and internal gear (27, 27', 27", 27"', 27"", 27""'; 26, 26', 26", 26"', 26"", 26""') serve exclusively for the stepping-down of the phase position, and the second spur and internal gear (28, 28', 28", 28"', 28""; 35, 35', 35", 35"', 35"", 35""', 35""") also serve for the stepping-down of the phase position or only as a coupling toothing for passing the driving and adjusting power through to the camshaft (14), characterized in that the internal and spur gears (26"'; 27, 27", 27"') are designed as internally or externally toothed annular gears which can be separated to the required length from tubes profiled with internal or external teeth.
2. Camshaft adjuster according to the precharacterizing clause of Claim 1, characterized in that the internal and spur gears (26""; 27, 27"', 27"") are formed from tooth-profiled strips to provide annular gears, are closed by welding or clipping and are subsequently recalibrated.
3. Camshaft adjuster according to the precharacterizing clause of Claim 1, characterized in that, instead of a pair of internal/spur gears transmitting the camshaft torque, the single internaleccentric gear mechanism (25, 25', 25", 25"', 25"" ) has a "ball orbital coupling" (49) in which balls (51), half of the sides of which are guided in circulating tracks (52) of two identical steel discs (50) which are under axial prestress, transmit the torque in a manner free from play and compensate for the eccentric movement, one of the steel discs (50) being connected in a rotationally fixed manner to a spur gear of the gear mechanism and the other being connected in a rotationally fixed manner to a part thereof which is mounted on the camshaft.

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