EP1718846B1 - Electric camshaft adjuster - Google Patents

Description

Field of the invention

The invention relates to an electric camshaft adjuster for adjusting and fixing the phase position of a camshaft of an internal combustion engine with respect to the crankshaft, with a non-rotatably connected to the crankshaft drive wheel, a camshaft fixed output member, and a corrugated transmission with at least one ring gear Stirnradpaarung, one of the two components rotatably with the drive wheel is connected and the other component is at least in a torque transmitting connection to the output part, wherein the spur gear is designed as a flexurally elastic sleeve and at least partially disposed within the first ring gear, with a driven by an electric adjusting motor via a transmission-fixed adjusting wave wave generator, the means for elliptical deformation of the flexurally elastic sleeve, whereby the sleeve is deformed such that between the ring gear and the sleeve at two opposite locations of the sleeve a drehmomentüb is made of the compound.

Background of the invention

In electric camshaft phasers, the low torque of the electric variable speed motor must be converted into the high torque required to adjust the camshaft. Serve this so-called three-shaft gear (summing). Their drive via a crankshaft fixed drive wheel and a drive shaft, while the output via an output shaft and a camshaft fixed output member takes place. The adjusting power is coupled by the electric adjusting motor via an adjusting shaft in one or the other direction in the three-shaft gear.

High demands are placed on the three-shaft transmissions. They should have a high efficiency, so that the electric adjusting motor and its heat loss remain small. In addition, the backlash of the teeth should be as low as possible, otherwise the highly variable alternating torque of the camshaft leads to unwanted noise. This is all the more so as the backlash between the teeth of adjustment and input and output shaft increased by the translation and thus the noise is amplified.

In addition, it is necessary to minimize the space for the three-shaft transmission, since modern vehicle engines must be built ever more compact in order to comply with the safety-related minimum distance between the body and vehicle engine.

Last but not least, the three-shaft transmission must be inexpensive to produce, in order to keep the system costs for an electric camshaft adjuster with adjusting gear, adjusting motor and control electronics low.

Double-shaft transmissions, double and single eccentric gearboxes as well as harmonic drives are considered as three-shaft transmissions. In particular, the latter appear to be suitable to meet the above requirements. Two versions of the wave gear are known, namely the wave gear in pot design and the sleeve design.

In the EP 1 039 100 A2 and the EP 1 039 101 A2 are wave gear in pot design shown. This design requires a relatively large amount of axial space and has an inherent axial thrust, which requires a corresponding storage. In addition, in the pot design, the risk of tilting and jamming of the wave generator by the toothing of the sleeve, especially a floating storage of the same because of their one-sided screwing is hardly possible. The teeth of this design requires a special profile that complicates a Umformtechnische production. In addition, instead of a low-cost standard deep groove ball bearing a complex thin-ring bearing is required.

In the WO 95/00748 is a camshaft adjuster disclosed with a corrugated transmission in sleeve design. In this design, no axial thrust occurs because the tilting forces in the toothing of the sleeve due to the floating support of the wave generator compensate and protect the wave generator from tilting and jamming. In addition, the sleeve design requires relatively little axial space. However, elaborate thin-ring bearings are also used for the wave generator in the above example. In addition, the arrangement of the drive wheel, driven part and ring gears in the example above requires considerable space.

Further camshaft adjusters are in DE 102 22 695 A1 . US Pat. No. 3,427,898 and DE 197 08 310 A1 shown.

Object of the invention

The invention is therefore an object of the invention to provide an electric camshaft adjuster with the least possible axial space and low construction costs, the adjustment is designed as a wave gear in sleeve design, weight optimized and inexpensive to manufacture.

Summary of the invention

The object is achieved in that the means for elliptical deformation of the flexible elastic sleeve two attached to the adjusting shaft, on two opposite Areas of the sleeve bearing journals are on each of which a roller bearing is arranged.

The modification of the components relates to the wave generator and the sleeve, while the integration relate to the arrangement of the drive wheel and the driven part and the first and second ring gear.

The telescoping drive wheel and driven part is made possible by the storage of the former on the second. The bearing used for this purpose is a four-point bearing. At this point, but also deep groove ball bearings, cylindrical roller bearings or plain bearings are conceivable.

The one-piece design of the gears of the corrugated transmission with the drive wheel and / or driven part of the camshaft adjuster reduces the number of components and thus the installation costs. At the same time, the production costs of the components can be reduced by using non-cutting production techniques. In this case, non-cutting forming processes, applied to a steel sheet suitable blank, as well as punching package. Also, the gears of the gears can be realized with these techniques.

Furthermore, it is provided that the sleeve is cup-shaped. The flexurally elastic sleeve cooperates with its outer circumferential surface with the inner circumferential surface of a ring gear in such a way that a torque-transmitting connection is formed between these surfaces.

The torque-transmitting connection between the ring gear and the sleeve can be realized by engaging in an internal toothing of the ring gear outer toothing of the sleeve, wherein the number of teeth of the internal toothing of the ring gear deviates from the number of teeth of the external toothing of the sleeve.

Another possibility is the execution as Reibradpaarung. The torque-transmitting connection between the ring gear and the sleeve is frictionally realized by the interaction of a smooth inner circumferential surface of the ring gear and a smooth outer surface of the sleeve. To improve the function is also provided to provide the coming into contact surfaces with friction linings.

The reduction of the wave gear we realized by the small number of teeth difference or the small difference of the radii of the ring gear and the sleeve. The sleeve is connected directly to the camshaft via the bottom extending radially inward from an axial end of the sleeve. The connection can be realized via a screw or positive-locking elements.

As an alternative to the embodiment in top form is provided that in the axial direction next to and coaxial with the first ring gear, a second ring gear is arranged, the sleeve is at least partially disposed within the second ring gear and enters at two opposite points a torque transmitting connection with the second ring gear.

It is provided that the sleeve in the axial direction at least partially and at least one ring gear are provided with a toothing. The teeth mesh with each other in the areas of the two points of intersection of the ellipse circumference with the major axis of the ellipse, whereby a torque-transmitting connection is made. The second spur ring pairing can be designed as Reibradpaarung or also as a gear pair.

It has advantages for a simple and low-wear power supply, when the electric variable motor is preferably designed as a bipolar brushless DC motor (BLDC motor) with rare-earth permanent magnets and cylinder-head fixed stator. But it is also conceivable, a DC motor with brushes or an asynchronous motor and a; Use electric motor with rotating stator.

Since the wave generator is floatingly mounted in the toothing of the wave gear, it is necessary that the motor shaft of the BLDC motor and the adjusting shaft have a connection by a rotationally fixed, but radially movable or compliant coupling, which is designed for example as a polymer coupling.

An advantageous further development of the invention is that the teeth of the wave gear have a profile shift. This is necessary because the teeth of the sleeve and the teeth of the first and second ring gear must mesh with each other, both of which have a different number of teeth but the same, matching the sleeve inner diameter.

An advantageous variant of the wave gear according to the invention is characterized in that the translation stage is designed as a friction gear, which has smooth surfaces instead of the teeth of the ring gear and the associated portion of the sleeve. In this way, the consolidation of the teeth of the 1: 1 coupling stage are simplified and reduces the running noise and wear.

It has advantages when a stop ring is attached to the drive wheel with a flag, which engages in a corresponding, ring-segment-shaped, the adjustment angle limiting recess of the driven part. This applies in particular to the friction gear version, in which a true-to-scale assignment of the friction wheels is not ensured.

It is also advantageous if a fixing ring, the outer diameter of which corresponds at least to the tooth tip diameter of the first ring gear, is pressed axially into the same and at its toothing. The fixing ring serves for the axial securing of adjusting shaft, wave generator and sleeve.

The dynamics of the camshaft adjustment is increased by the fact that at least the adjusting shaft has recesses for the purpose of weight reduction and / or consists of light metal, plastic or a composite material. In addition, it is provided that at least one of, but possibly also all gear components for the purpose of weight reduction of light metal, plastic or a composite material.

Manufacturing advantages for the wave gear arise when the components of the same are made uncured and without cutting and at least the Gearing is subsequently hardened or nitrided. In this way, the sleeve can be made by drawing. It is also conceivable that the ring gears are produced by stamped packetizing.

As a means for elliptical deformation of the flexurally elastic sleeve, a corrugated ring with an elliptical outer circumference and an elliptically deformed rolling bearing mounted thereon are provided. In the execution. the corrugated gear with toothed spur gear is provided that the outer ring of the rolling bearing and the externally toothed sleeve are made in one piece, whereby the number of components and thus the installation costs can be reduced. As rolling bearings groove ball, roller or needle roller bearings come into question. But plain bearings are also conceivable.

Furthermore, it is provided that the elliptical corrugated ring and the inner ring of the rolling bearing are made in one piece. If the elliptical surface of the wave generator serves as a running surface for the rolling elements, the inner ring of the standard rolling bearing is unnecessary. This saves another component of the wave gear.

A further embodiment of the invention provides for the use of two bearing journals mounted on the adjusting shaft and bearing against two opposite regions of the sleeve as a means for elliptical deformation of the bending-elastic sleeve instead of a solid or hollow shaft. As a result, the weight of the camshaft adjuster, especially the weight of rotating parts and thus the moment of inertia, significantly reduced.

To minimize friction, a rolling bearing is arranged on each journal. The inner ring of the rolling bearing is supported on the bearing pin, while the sleeve is supported on the outer ring. If the adjusting shaft and the drive wheel rotate at different rotational speeds, then the outer ring of the roller bearing rolls on the inner lateral surface of the sleeve.

In an advantageous embodiment of the invention, the bearing journals are mounted with an eccentric fastening means and rotatably mounted on the adjusting shaft and fixed thereto in any angle of rotation. With the help of this measure, a simple clearance adjustment between the outer toothing of the sleeve and the internal toothing of the ring gears is possible.

Alternatively, it is provided for minimizing the play between the external toothing of the sleeve and the internal toothing of the ring gears that the roller bearings have eccentrically formed inner rings which can be pressed onto the bearing journals in any desired angle of rotation. As a result, a continuous adjustment of the backlash is possible. But it is also possible to provide Verstellwellen having a stepped deviation of the reference distance of the bearing pin from the axis of the adjusting shafts to be installed in the selection process.

The two rolling bearings can be designed as ball bearings, preferably deep groove ball bearings, cylindrical roller or needle roller bearings. Due to the principle of the two standard bearings are not deformed during operation, so that they are not exposed to additional load. Compared to an elliptical wave generator, the sleeve is not supported on the entire circumference but only at the points of meshing.

Brief description of the drawings

Figur 1

einen Längsschnitt eines Wellgetriebes mit einem Wellgenerator, der ein Standard-Rillenkugellager aufweist;

Figur 2

eine Ansicht eines Wellgetriebes mit Hohlrädern und einer flexiblen, außenverzahnten Hülse;

Figur 3a

ein unverformtes Wälzlager der Hülse;

Figur 3b

ein auf das gewünschte Ellipsenmaß verformtes Wälzlager der Hülse;

Figur 3c

eine Vermessung des Innenrings des Wälzlagers der Hülse;

Figur 4

ein Längsschnitt durch ein Standard-Rillenkugellager mit verzahntem Außenring;

Figur 5

eine Ansicht des Standard-Rillenkugellagers von Figur 4;

Figur 6

einen Längsschnitt durch eine Verstellwelle mit einem Wellgenerator,

Figur 7

einen Längsschnitt durch eine Variante des Wellgetriebes von Figur 1 mit einer modifizierten Verstellwelle;

Figur 8

einen Längsschnitt durch einen Nockenwellenversteller mit einer dritten Ausführungsform einer Verstellwelle.

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. Show it:

FIG. 1

a longitudinal section of a wave gear with a wave generator having a standard deep groove ball bearing;

FIG. 2

a view of a corrugated transmission with ring gears and a flexible, externally toothed sleeve;

FIG. 3a

an undeformed roller bearing of the sleeve;

FIG. 3b

a rolling bearing of the sleeve deformed to the desired ellipse dimension;

Figure 3c

a measurement of the inner ring of the rolling bearing of the sleeve;

FIG. 4

a longitudinal section through a standard deep groove ball bearing with toothed outer ring;

FIG. 5

a view of the standard deep groove ball bearing of FIG. 4 ;

FIG. 6

a longitudinal section through an adjusting shaft with a wave generator,

FIG. 7

a longitudinal section through a variant of the wave gear of FIG. 1 with a modified adjusting shaft;

FIG. 8

a longitudinal section through a camshaft adjuster with a third embodiment of an adjusting shaft.

Detailed description of the drawings

In FIG. 1 is a longitudinal section through a camshaft adjuster according to the invention shown. This has a trained as a sprocket drive wheel 1, which is rotationally connected via a chain, not shown, with a crankshaft, not shown. It is also conceivable, of course, to design the drive wheel 1 as a toothed belt wheel or spur gear, which is driven by a toothed belt or a spur gear. The drive wheel 1 and a first ring gear 2 are integrally formed, wherein the first ring gear 2 has a first internal toothing 3. An output part 4, which is designed in one piece with a second ring gear 5, is rotationally connected to a camshaft, not shown. The second ring gear 5 has a second internal toothing 6 and is adjacent in the axial direction and coaxial with the first Ring gear 2 arranged. The drive wheel 1 is mounted together with the first ring gear 2 by means of a four-point bearing 7, which is arranged radially and axially within the drive wheel 1, via the second ring gear 5 and the output part 4 on the camshaft, not shown. The four-point bearing can, as shown, be designed as a separate component with inner ring, rolling elements, cage and outer ring. In a further advantageous embodiment, the Wälzkörperlaufbahnen are formed directly on the drive wheel 1 and the second ring gear 5, whereby the inner and the outer ring of the rolling bearing omitted and the number of components is reduced. In addition to the illustrated ball bearing needle or roller bearings are used. At the drive wheel 1, a stop ring 22, for example, by means of screws 23, rivets, welded joints or caulking attached. This carries a flag 8, which engages in a corresponding ring-segment-shaped, the adjustment angle limiting recess 9 of the driven part 4. Likewise conceivable are embodiments in which the adjustment angle limiting recess 9 is introduced into the drive wheel 1, in which engages a rotatably connected to the output member 4 element.

An adjusting shaft 10 has a toothed coupling 24 for an electric adjusting motor, not shown. Of course, other couplings, such as polymer clutches or magnetic clutches are conceivable that can compensate occurring between the transmission shaft and the electric motor shaft axial and radial offset. The adjusting shaft 10 is connected to a corrugated ring 11, which has an elliptical outer contour 12. On this is a roller bearing 13, the inner ring 14 and outer ring 15 of the same take on the elliptical shape of the corrugated ring 11 when pressing. In addition to the illustrated ball bearing, preferably deep groove ball bearings and other rolling bearing designs are conceivable, such as cylindrical roller or needle roller bearings. The rolling bearing 13, which is axially secured by a snap ring 16, forms, together with the elliptical corrugated ring 11, a wave generator 17 as part of the wave gear 19.

On the outer ring 15 of the rolling bearing 13, an elastic sleeve 18 is pressed with external teeth 28, wherein the sleeve 18 also takes on the elliptical shape during pressing. The sleeve 18 can be secured by means of positive locking means against axial wandering on the rolling bearing 13. This can be realized for example by radially inwardly directed curls of the axial ends of the sleeve 18.

The wave generator 17 and the sleeve 18 are designed such that they can be arranged radially within the ring gears 2, 5. In this case, the wave generator 17 abuts the output part 4 in the axial direction. For axial fixation of the sleeve 18 and the wave generator 17, a fixing ring 20 is pressed into the first ring gear 2 on the side remote from the stripping section 4, whose outer diameter corresponds to at least the Zahnfußdurchmesser the first ring gear 2 and the same rests on the inner toothing 3 thereof. The wave generator 17 and the sleeve 18 are now in the axial direction between the driven part 4 and the fixing ring 20. The elliptically deformed sleeve 18 engages with its external teeth 28 in the areas of the two intersection points of the ellipse circumference with the main axis of the ellipse in the first and second internal teeth 3, 6 of the ring gears 2, 5 a.

The internal teeth 3, 6 of each ring gear 2, 5 is thus in engagement with the external teeth 28 of the sleeve 18 in two areas. Due to the elliptical deformation of the sleeve 18 ensures that these areas are located at opposite locations with respect to the center of the respective ring gear 2, 5 at this.

In FIG. 2 is the wave gear 19 with the sleeve 18 and the ring gears 2, 5 shown in a simplified side view. It can be clearly seen that the outer toothing 28 of the elliptically deformed sleeve 18 engages in two areas of the first and second internal toothing 3, 6 of the ring gears 2, 5. One of the ring gears 2, 5 has the same number of teeth as the sleeve 18, the other ring gear 2, 5 has z. B. two more teeth. Profile displacement makes it possible that the external teeth 28 of the elliptical sleeve 18 with both ring gears 2, 5 despite their different number of teeth at the same time engaged, and at two opposite points of the same. The ring gear 2 or 5 with the same number of teeth as the sleeve 18 acts as a 1: 1 gear coupling, the ring gear 2 or 5 with the increased number of teeth as a translation stage. Which of the two ring gears 2 or 5 the same and which has the larger number of teeth, depends on the direction in which the wave gear 19 is to adjust when the adjusting shaft 10 is stationary, ie, whether it should work as a plus or a minus gear. It is also conceivable that the numbers of teeth of all gears 3, 6 and 28 differ. In this way, the size of the profile displacement on a toothing 3, 6 and 28 are limited to a minimum. It is also conceivable to carry out the external toothing 28 of the sleeve 18 as a split external toothing, with one part of the toothing engaging in the first internal toothing, 3 and the second part of the toothing engaging in the second internal toothing 6. The two external teeth can be designed differently. By way of example, the number of teeth or tooth module should be mentioned here. In this way, the profile displacements can be reduced or different modules can be used for a better load capacity

The drive wheel 1, which is designed in one piece with the first ring gear 2, the output part 4, which is designed in one piece with the second ring gear 5 and the sleeve 18 are preferably produced in non-cutting shaping process. The use of chip removal techniques reduces both the weight of the individual components and their production costs in mass production. The individual components including the teeth 3, 6, 28 can be advantageously made of sheet steel in a chipless forming process. It is also conceivable to produce the components by stamped packetizing.

The wave gear 19 after the FIGS. 1 and 2 works in the following way: With one revolution of the adjusting shaft 10, the wave generator 17 also makes one revolution. In this case, the external toothing 28 of the elliptical sleeve 18 is simultaneously rolled on the internal teeth 3, 6 of the first and second ring gear 2, 5.

If the first ring gear 2 has the same number of teeth as the elliptical sleeve 18, then the output tooth of the sleeve 18 again engages in its initial tooth gap after one revolution of the adjusting shaft 10. Thus, the position of the sleeve 18 relative to the first ring gear 2 has not changed and there is a 1: 1 gear coupling before.

Does the second internal toothing 6 of the second ring gear 5 z. B. two teeth more than the outer teeth 28 of the sleeve 18, then engages the output tooth of the sleeve 18 after a revolution of the adjusting 10 in a tooth space of the second ring gear 5, which is two tooth gaps before the original. Thus, the sleeve 18 per revolution of the adjusting shaft 10 by two teeth back, so that the sleeve 18 in proportion to the total number of teeth. of the second ring gear 5 (eg, 300 teeth) to the difference number of teeth two (ie, 300: 2 = 150: 1) rotates counter to the adjusting shaft 10, that is, as shown in FIG. h., has a translation of 150: 1 slow.

In a further advantageous embodiment of the invention, the spur-Hohlradpaarung which is responsible for the reduction is designed as Reibradpaarung, while the other spur Hohlradpaarung cooperates via gears and is preferably designed as a 1: 1 clutch. The outer toothing 28 of the sleeve 18 extends in the axial direction only in the region in which, the sleeve 18 is within the other ring gear 2 or 5. The other area is smooth and cooperates with the also smooth running inner surface of the corresponding ring gear 2 together. Both the toothings 6, 28 of the first spur ring gear pairing and the smooth surfaces of the second spur ring gear pair act together due to the elliptically deformed sleeve 18 at two opposite areas.

Another embodiment of the invention provides only a spur gear pair. Conceivable torque transmission is again about teeth 2, 28 or friction. The drive wheel 1 is formed integrally with the ring gear 2. The sleeve 18 is cup-shaped, wherein the camshaft is mounted rotationally fixed at the bottom.

The geometry of the ellipse of the wave generator 17 may according to the FIGS. 3a, 3b, 3c be determined:

In FIG. 3a an undeformed standard rolling bearing 13 is shown.

In FIG. 3b the standard rolling bearing 13 is compressed at two opposite points on the outer ring 15 in the direction of the arrows F until the desired maximum ellipse dimension 21 is reached on the outer ring 15.

In Figure 3c the elliptical inner contour of the inner ring 14 is measured and possibly corrected, after which the elliptical outer contour 12 of the corrugated ring 11 of the wave generator 17 is produced.

In FIG. 4 is a longitudinal section through a further embodiment of a deep groove ball bearing designed roller bearing 13 'is shown, the outer ring: 15' carries the outer teeth 28 of the sleeve 18 and thus can take their place. The elimination of the sleeve 18, of course, has a cost-reducing effect.

FIG. 5 shows a front view of the rolling bearing 13 'from FIG. 4 with the one-piece with the outer ring 15 'running external teeth 28th

In FIG. 6 is a longitudinal section through a wave generator 17 'with an adjusting shaft 10' and an outer toothing 28 is shown. The corrugated generator 17 'has a corrugated ring 11' and a roller bearing 13 "designed as a cylindrical roller bearing The cylindrical roller bearing consists of a plurality of cylindrical rollers 26 which are arranged between an inner ring 14 'and an outer ring 15" and for relative movements between the rolling bearing rings 14', 15 The inner ring 14 'is embodied in one piece with the corrugated ring 11' The cylindrical rollers 26 of the rolling bearing 13 "run directly on the elliptical outer contour 12 'of the correspondingly enlarged corrugated ring 11'. The external toothing 28 is formed directly on the outer ring 15 "of the rolling bearing 13". As compared to the first embodiment, the cyclic deformation of the inner ring 14 'and the sleeve 18 is omitted, the power of the electric adjusting motor can be correspondingly lower.

In FIG. 7 is a longitudinal section through a wave gear 19 ', a variant of the wave gear 19 of FIG. 1 In this case, an adjusting shaft 10 "instead of a corrugated ring has two axial bearing journals 29 with two standard roller bearings 13"'designed as deep groove ball bearings 29, while the sleeve 18 is supported on the outer rings 15 "'. The bearing journals 29 are offset by 180 ° and arranged at the same distance from the axis 30 of the adjusting shaft 10". The distance is chosen so that the sleeve 18 in the same manner as by the corrugated ring 11 of FIG. 1 is deformed elliptical.

In order to minimize backlash, the inner rings 25 of the roller bearings 13 "'can be formed as eccentric inner rings 25. By installing the same with corresponding rotation angle, the backlash between the teeth of the sleeve 18 and the ring gears 2, 5 can be adjusted.

This goal is also served in FIG. 8 shown, multi-part adjusting shaft 10 '', the eccentrically formed axial bearing pin 29 'by clamping screws 27 in any Verdrehwinkellage be fastened.

In a further embodiment, the inner rings 25 of the roller bearings 13 "'in one piece with the bearing pins 29, 29' executed, ie, the raceways of the rolling elements are introduced into the outer circumferential surface of the bearing pins 29, 29 '.

LIST OF REFERENCE NUMBERS

1

drive wheel

2

first ring gear

3

first internal toothing

4

stripping section

5

second ring gear

6

second internal toothing.

7

Four point contact bearings

8th

Banner, flag

9

recess

10, 10 ', 10 ", 10"'

adjusting

11, 11 '

corrugated ring

12, 12 '

elliptical outer contour

13, 13 ', 13 ", 13"'

roller bearing

14, 14 '

inner ring

15, 15 ', 15 ", 15"'

outer ring

16

snap ring

17, 17 ', 17 "

wave generator

18

shell

19, 19 '

The wave gear

20

fixing

21

maximum ellipse dimension

22

stop ring

23

screw

24

gear coupling

25

eccentric inner ring

26

cylindrical roller

27

clamping screw

28

external teeth

29, 29 '

axial bearing journal

30

axis

Claims (18)

1. Electric camshaft adjuster for adjusting and securing the phase angle of a camshaft of an internal combustion engine with respect to its crankshaft, having

   - a drive wheel (1) which is connected fixedly in terms of rotation to the crankshaft,

   - an output component (4) which is fixed to the camshaft, and

   - a harmonic drive

   - having at least one ring gear-spur gear pairing,

   - one of the two components being connected fixedly in terms of rotation to the drive wheel (1), and the other component having at least a torque-transmitting connection to the output component (4),

   - the spur gear being embodied as a flexurally elastic sleeve (18) and

   - being arranged at least partially within the first ring gear (2, 5),

   - having a wave generator (17") which is driven by an electric adjustment motor by means of an adjustment shaft (10", 10"') which is fixed to the gearing,

   - which wave generator (17, 17', 17") has means for elliptically deforming the flexurally elastic sleeve (18),

   - as a result of which the sleeve (18) is deformed in such a way that a torque-transmitting connection is formed between the ring gear (2, 5) and the sleeve (18) at two points on the sleeve (18) lying opposite one another, characterized in that

   - the means for elliptically deforming the flexurally elastic sleeve (18) are two bearing journals (29) which are attached to the adjustment shaft (10", 10"') and bear against two regions of the sleeve (18) lying opposite one another, a roller bearing (13"') being arranged on each of said bearing journals (29).
2. Camshaft adjuster according to Claim 1, characterized in that the sleeve (18) is of pot-shaped design.
3. Camshaft adjuster according to Claim 1, characterized in that a second ring gear (5) is arranged in the axial direction next to the first ring gear (2) and coaxially with respect thereto, the sleeve (18) is arranged at least partially within the second ring gear (5) and enters into a torque-transmitting connection with the second ring gear (5) at two points lying opposite one another.
4. Camshaft adjuster according to Claim 1, characterized in that the torque-transmitting connection between the ring gear (2, 5) and the sleeve (18) is implemented by means of an external toothing (28) of the sleeve (18) which engages in an internal toothing (3, 6) of the ring gear (2, 5), and the number of teeth of the internal toothing (3, 6) of the ring gear (2, 5) differs from the number of teeth of the external toothing (28) of the sleeve (18).
5. Camshaft adjuster according to Claim 1, characterized in that the torque-transmitting connection between the ring gear (2, 5) and the sleeve (18) is implemented in a frictionally locking fashion by means of the interaction of the smooth internal lateral face of the ring gear (2, 5) and the smooth external lateral face of the sleeve (18).
6. Camshaft adjuster according to Claim 1, characterized in that the electric adjustment motor is preferably embodied as a brushless DC motor (BLDC motor) which is operated in bipolar fashion and has a stator fixed to the cylinder head and preferably a rare earth magnet.
7. Camshaft adjuster according to Claim 1, characterized in that the motor shaft of the BLDC motor and the adjustment shaft (10, 10', 10", 10"') have a connection by means of a rotationally fixed but radially movable or resilient coupling, which is preferably embodied as a polymer coupling (26).
8. Camshaft adjuster according to Claim 1, characterized in that a stop ring (22) is attached to the drive wheel (1) and has a lug (8) which engages in a corresponding, annular-segment-shaped cut-out (9), which limits the adjustment angle, of the output component (4).
9. Camshaft adjuster according to Claim 1, characterized in that a securing ring (20) whose external diameter corresponds at least to the tooth head diameter of the first ring gear (2) can be pressed into the latter.
10. Camshaft adjuster according to Claim 1, characterized in that at least the adjustment shaft (10, 10', 10" , 10"') can have cut-outs for the purpose of reducing the weight and/or can be composed of lightweight metal, plastic or a composite material.
11. Camshaft adjuster according to Claim 4, characterized in that at least one of the toothing components (3, 6, 28) is composed of lightweight metal, plastic or a composite material in order to reduce the weight.
12. Camshaft adjuster according to Claim 1, characterized in that all the components or individual components, preferably the toothing components (3, 6, 28), of the harmonic drive (19, 19') are fabricated in a non-material-removing fashion.
13. Camshaft adjuster according to Claim 4, characterized in that the components of the harmonic drive (19, 19') are fabricated in a non-material-removing fashion, and the toothings (3, 6, 28) are subsequently hardened or nitrated.
14. Camshaft adjuster according to Claim 1, characterized in that the means for elliptically deforming the flexurally elastic sleeve (18) is a wave ring (11, 11') with an elliptical external circumference (12) and an elliptically deformed roller bearing (13, 13', 13") attached thereto.
15. Camshaft adjuster according to Claim 4, characterized in that the means for elliptically deforming the flexurally elastic sleeve (18) is a wave ring (11, 11') with an elliptical external circumference (12) and an elliptically deformed roller bearing (13', 13") attached thereto, and the external ring (15") of the roller bearing (13', 13") and the externally toothed sleeve (18) are embodied in one piece.
16. Camshaft adjuster according to Claim 14, characterized in that the elliptical wave ring (11') and the internal ring (14') of the roller bearing (13") are embodied in one piece.
17. Camshaft adjuster according to Claim 1, characterized in that the bearing journals (29') are rotatably attached to the adjustment shaft (10"') using an eccentric fastening means and can be secured in any desired rotational angle position.
18. Camshaft adjuster according to Claim 1, characterized in that the roller bearings (13"') have eccentrically formed internal rings (25) which can be pressed onto the bearing journals (29) in any desired rotational angle position.

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