DE102004038695A1 - Camshaft drive with a camshaft adjuster - Google Patents

Abstract

The invention relates to a camshaft drive with a camshaft adjuster (10), which has a chain driven by a chain (11), a servomotor and a transmission, wherein by means of the transmission, the drive movement of the sprocket (11) on a camshaft (12) is transferable and a relative angle of rotation between the sprocket (11) and the camshaft (12) can be varied in accordance with an actuating movement of the servomotor. DOLLAR A According to the invention, a gear (ring gear 19) is not detachable (for example, in one piece, by shrinking or press fitting or cohesively) connected to the camshaft. This results in a simplification of the structure, a reduction in the variety of parts and a stiffer connection of the gear (ring gear 19) to the camshaft 12th

Description

Territory of invention

The The invention relates to a camshaft adjuster according to the preambles of the claims 1 and 7.

background the invention

From the DE 36 16 234 A1 is a camshaft drive with a camshaft adjuster known. The camshaft adjuster has a driven by a chain drive wheel, designed as a hydraulic motor actuator and a transmission. By means of the transmission, the drive movement of the drive wheel is transferable to a camshaft. In accordance with an adjusting movement of the hydraulic motor, a relative angle of rotation between the drive element and the camshaft for changing the inlet and outlet times of an internal combustion engine is variable. In the area of the camshaft adjuster, the camshaft is radially widened and includes a recess within which further parts of the camshaft adjuster are arranged. On a lateral surface of the expansion of the drive wheel is rotatably supported. A support of the drive torque of the drive wheel via a tubular hub, which has on the inside via a helical toothing. With the helical toothing of the hub is in positive engagement a coupling member, which is a straight toothing in positive engagement with the camshaft, see. also DE 39 29 623 A1 , Accordingly, the camshaft known in the cited documents is used in addition to the function of actuation of the inlet and outlet valves in addition to a radial support of a drive element, housing-like forms an interior and supports radially inside other components of the camshaft adjuster.

From the DE 196 11 365 C2 It is known to screw a screw into the front side of the camshaft, which is formed integrally with a arranged on the side facing away from the camshaft side of the camshaft adjuster lid.

From the DE 199 55 507 C2 a camshaft adjuster is known in which on an end face screwed to the camshaft screw an inner body is mounted and a shaft nut is screwed. The screw forms in the covering area to the mother a housing for a spool. According to an alternative embodiment, the screw connection is integrally connected to the camshaft, for example as a cast or forged part.

From the DE 689 19 896 T2 It is known that the end portion of a camshaft protrudes into a camshaft adjuster, wherein the end portion has two intermediate regions of different diameters, which are positively connected to the camshaft moving components of the camshaft adjuster.

Task of invention

Of the Invention is based on the object to a camshaft drive create, taking into account of manufacturing facilities one ensures multifunctional use of the camshaft

Summary the invention

According to the invention Problem solved by the features of independent claim 1. One Gear of the camshaft adjuster or a bridge, opposite which a gear such as a planet gear of the transmission is rotatably mounted is not solvable connected to the camshaft, creating a direct transmission a drive movement of the drive element to the camshaft is possible. This allows a particularly rigid connection of the gear the camshaft or over an elastic coupling a connection with defined stiffness be achieved. Furthermore, a game between camshaft and Gear are excluded. The number of necessary components and the assembly steps decreases, since the gear and the Camshaft form a structural unit.

Under not solvable is understood in this context that the connection between gear and camshaft not using simple, conventional tools or without a thermal or plastic deformation can be solved. For example becomes the releasable Connection cohesively manufactured, in particular by means of welding, gluing, friction welding, soldering or Laser engraving welding. Furthermore, it is possible that the connection by a press connection, for example a press fit or a compound provided under a shrinkage, is made. Also possible is a forming connection which involves the application a plastic deformation includes. Such a connection can for example, a radial knurling or a wedge connection in combination with a caulking or a crimp for one be axial fuse. Furthermore, a positive connection or a Diffussionsverbund be made by a sintering bonding. A combination of several The aforementioned types of connection is also possible.

By the invention, not detachable connection the gear to the camshaft, for example, binding to a connection via a screw connection be waived. In such screw according to the state The technology to be attached to the camshaft components via clamping forces between held the screw head and the camshaft. This will be axial forces introduced into components of the camshaft adjuster and in the camshaft. These axial forces to lead to an additional Loading both the components of the camshaft adjuster as well the camshaft, which alone or in conjunction with additional Strains such as the force of a traction device or the torque to be transmitted from the camshaft or component stress states cause. Furthermore, the threads represent a weakening of the components and the camshaft. In addition it can come to deformations due to the axial force, for example to a bulge of a camshaft bearing or bearings in the camshaft adjuster, which affect necessary functional cycles can. To counteract this, it is in a conventional solution necessary to increase the tolerance range of the function games, as a Game to compensate for the incoming deformations got to. Furthermore, the introduction of a thread in the camshaft an elevated one Machining costs, as these usually cutting into the camshaft be introduced. This creates an additional risk of contamination as a result of chips o. Ä. A Another disadvantage of a compound of the components of the camshaft adjuster with the camshaft over A screw connection is that a high number of individual parts must be used as well as specially processed for the connection functional surfaces must be provided meet the high requirements have to. About that an enlarged one conventional Screw connection an error risk for the design and assembly. For example, depends the position of the screw and the component fastened with the screw from the production of both the thread of the camshaft and the Screw yourself off as well as the correct screwing and tightening the screw during the assembly. additionally represents the screw connection in the tolerance chain between the drive element and camshaft is another uncertainty, which centering games and manufacturing defects can. Through such games or mistakes, deviations between a predetermined Winkelbezie hung between the camshaft and crankshaft result. Another disadvantage for a compound of a gear over a screw connection with the camshaft needs for a screw an additional one Space to be provided.

at the transmission according to the invention it may be a transmission of any type, in particular a high translating Three-shaft transmission, a single or double internal eccentric transmission, a pulley transmission, a swashplate transmission, a Wolfromgetriebe, a planetary gear, a wave gear, a Planoflex gear or act a hydraulic transmission. The actuator can be electric, be formed electromagnetically or hydraulically. A special good controllability over one suitable control device results for an electric actuator.

The Gear can be directly in the area of a lateral surface of the Camshaft be provided. After an alternative suggestion of Invention is the gear from a radially to the camshaft worn extending flange. This is particularly advantageous if the camshaft on the one hand and the gear on the other hand different Have diameter. Such differences in diameter can by the flange can be bridged in a simple way and with a low weight, the non-releasable compound both between flange and camshaft as well as between flange and gear ensures a rigid connection in a compact design.

• – die Nockenwelle und das Zahnrad,
• – der Flansch und das Zahnrad,
• – die Nockenwelle und der Flansch oder
• – die Nockenwelle, der Flansch und das Zahnrad

einstückig miteinander ausgebildet sind. Dies führt zu einer besonders steifen Anbindung von Flansch bzw. Zahnrad an die Nockenwelle. Gleichzeitig können unter Umständen Fertigungskosten im Vergleich zu einer separaten Fertigung von Flansch bzw. Zahnrad und Nockenwelle reduziert werden sowie die Montage vereinfacht werden. Bei einer derartigen Nockenwelle handelt es sich beispielsweise um eine Nockenwelle, welche mittels Gießen hergestellt ist, welche ein Schmiedeteil ist oder welche durch Innenhochdruckumformen hergestellt ist. Nach einem derartigen Herstellungsverfahren kann zusätzlich eine weitere Nachbearbeitung erfolgen, mittels welcher Nockenwelle, Zahnrad und/oder Flansch in die endgültigen Abmessungen gebracht werden. Insbesondere kann eine Verzahnung nachträglich spanend, beispielsweise durch Stoßen, eingebracht werden.A particularly simple and compact camshaft drive arises when

• The camshaft and the gear,
• - the flange and the gear,
• - the camshaft and the flange or
• - the camshaft, the flange and the gear

are integrally formed with each other. This leads to a particularly rigid connection of flange or gear to the camshaft. At the same time, manufacturing costs can be reduced as compared to a separate production of flange or gear and camshaft and the assembly can be simplified. Such a camshaft is, for example, a camshaft which is produced by casting, which is a forged part or which is produced by hydroforming. After such a manufacturing process, a further post-processing can additionally be carried out, by means of which camshaft, gear and / or flange are brought to the final dimensions. In particular, a toothing can be subsequently machined, for example by impact.

A multi-functional use of the camshaft is given for a further embodiment of the camshaft, in which the camshaft has an outer circumferential surface which serves as a bearing surface for a relative to the camshaft moving component. This embodiment of the invention makes use of that to the cams of Camshaft and bearing surfaces comparable requirements, for example, in terms of material and surfaces are to be made. According to the invention, therefore, the bearing surfaces can already be finished and / or finished during the production of the camshaft. In addition, a particularly good and stiff as well as automatically aligned relative to the camshaft bearing surface, if this is provided directly on the camshaft.

A special adaptation of the camshaft drive according to the invention an internal eccentric gear is possible when the gear, which is not detachably connected to the camshaft is a ring gear of the Innenexzentergetriebes is. In this case This results in a particularly compact Innenexzentergetriebe, in which a rigid connection of the ring gear is ensured. In addition, necessary Sealing points between the ring gear and the camshaft through the inventive design be avoided.

A another, alternative solution The object of the invention is based on the features of the independent claim 7 given. Accordingly, the Camshaft indissoluble with connected to an axial extension. About the axial extension takes place a support of components of the camshaft adjuster. In this way can continuation and camshaft first be made in separate steps, followed by a firm connection between camshaft and extension is made, which is particularly durable and an exact determination of the Ensured position of the axial extension relative to the camshaft. When not soluble Connection is the aforementioned connection types. Especially Pressing or shrinking of the axial extension takes place. For a production over a Hydroforming may be in the axial extension to an insert act, which is radially expanded.

According to one Development of the invention, the axial extension has an external Shell surface, as a storage area for a relative to the Camshaft moving component is used. This can be a stiff connection of the bearing to the camshaft can be achieved.

According to one preferred embodiment of the invention is the axial extension in an axial bore of the front side of the Camshaft used. In such an axial bore can it is a blind hole, for example, only serves to receive the axial extension. Alternatively, the axial Bore be formed as a through hole of the camshaft, which to a weight reduction of the camshaft and thus the rotating mass of the cam drive leads. In addition, the axial bore for further Purpose serve, for example, to guide a hydraulic fluid or a lubricant.

• – einer nicht lösbaren Verbindung des Zahnrades mit der Nockenwelle sowie
• – einer Abstützung von Bauteilen des Nockenwellenverstellers über einen axialen Fortsatz, der unlösbar mit der Nockenwelle verbunden ist,

zu kombinieren, wodurch eine Verbindung der vorgenannten Vorteile erzielt werden kann und eine besonders kompakte Einrichtung resultiert.The invention also proposes the aforementioned separate approaches

• - A non-detachable connection of the gear with the camshaft and
• - A support of components of the camshaft adjuster via an axial extension which is permanently connected to the camshaft,

to combine, whereby a combination of the aforementioned advantages can be achieved and a particularly compact device results.

advantageous Further developments will become apparent from the dependent claims, the description and the Drawings.

Short description the drawings

Further Features of the invention will become apparent from the following description and its associated Drawings in which embodiments of the invention are shown schematically. Show it:

1 a first camshaft drive according to the invention with a camshaft adjuster, in which a ring gear is formed integrally with a camshaft via a flange;

2 a camshaft drive according to the invention with a camshaft adjuster according to a second embodiment, in which a ring gear of the camshaft adjuster is integral with a flange and the camshaft female receiving and a support of an eccentric shaft on a bearing surface of the camshaft;

3 a camshaft drive according to the invention with a camshaft adjuster according to a third embodiment of the invention, in which a ring gear, a flange and a sleeve are integrally formed and are not detachably connected to the camshaft, wherein an eccentric shaft is supported via an outer surface of the bush in a bearing.

Full Description of the invention

The invention is merely exemplary of a phaser 10 shown with inner eccentric gear.

A transmission of a drive movement of a drive element 11 , here a sprocket, to a camshaft 12 occurs with the interposition of a coupling agent 13 , According to a control unit, not shown in the figures, the angular position between the drive element 11 and the camshaft 12 be changed to change the timing of an internal combustion engine.

According to 1 owns the camshaft 12 at least in the area of cams 14 an axial bore 15 , In the camshaft adjuster 10 assigned end area goes the hole 15 in a recess 16 over which particular one opposite the bore 15 Has enlarged area. The hole 16 is limited by a closed ring section 17 , which in a radially oriented, substantially annular flange 18 passes. Radial outboard carries the flange 18 a ring gear 19 , which has an internal toothing 20 features. camshaft 12 , Flange 18 and ring gear 19 are for the in 1 illustrated embodiment integrally formed with each other.

The drive element 11 is fixed to a socket 21 and a ring gear 22 connected, wherein the ring gear one opposite the socket 21 has reduced diameter. According to 1 are driving element 11 , Rifle 21 and ring gear 22 formed integrally with each other.

The socket 21 is for mounting in the direction of the cams 14 on the ring gear 19 pushed, wherein an outer circumferential surface of the ring gear 19 and an inner circumferential surface of the socket 21 a support and location of the socket 21 while ensuring a relative movement between the ring gear 19 and socket 21 deploy around the X-X axis. An axial determination of the position of the socket 21 opposite the ring gear 19 via a in which the ring gear 22 remote end portion of the socket 21 arranged fuse element 23 ,

The coupling agent 13 has on the lateral surface a toothing, on a partial circumference with the ring gear 22 meshes, as well as a toothing whose diameter is increased compared to the aforementioned toothing and which at a partial circumference with the ring gear 19 combs.

Radially inward, the coupling agent is supported 13 via a rolling bearing, here a needle bearing 24 , opposite to an eccentric shaft 25 from whose longitudinal axis is offset by an eccentricity with respect to the longitudinal axis X-X. The eccentric shaft 25 is about a clutch 26 in drive connection with a control unit. The eccentric shaft 25 has a bore aligned with the X-X axis 27 , in which a rolling bearing, here a needle bearing 28 , recorded.

In the recess 16 the camshaft 12 is an axial extension 29 not releasably introduced. In the connection region of the axial extension 29 to the camshaft 12 its lateral surface is corresponding to the recess 16 educated. In addition to the already mentioned types of connection can recess 16 and the associated lateral surface of the axial extension 29 not be round, so that the connection between extension 29 and camshaft 12 at least in the circumferential direction is positively. In one of the camshaft 12 cantilevered portion 30 owns the extension 29 a cylindrical surface, which is a bearing surface 31 forms on which the needle bearing 28 rolls.

On the cam 14 opposite side is the camshaft adjuster with a housing cover 32 locked.

Preferably takes place in the region of the flange 18 an axial support of the needle bearing 28 or a cage or a bearing disc thereof, the eccentric shaft 25 , the needle bearing 24 or a cage or a bearing disc thereof and / or the coupling element 13 while ensuring a relative movement.

According to the in 2 illustrated embodiment is - otherwise 1 corresponding embodiment - the axial extension 29 integral with the camshaft 12 connected so that the camshaft 12 directly the storage area 31 formed. Between cams 14 and the storage area 31 has the camshaft 12 via a support surface 32 , From the end of the camshaft 12 is a jack 33 on the support surface 32 applied, with the socket 33 in the area of the support surface 32 a non-detachable connection with the camshaft 12 received. The socket 33 is integral with the flange 18 and the ring gear 19 educated. The camshaft 12 has on the cam 14 facing side over a paragraph 34 over which the axial position of the bush 33 with flange 18 and ring gear 19 during a connection between socket 33 and camshaft 12 can be specified.

According to the in 3 illustrated embodiment has the camshaft 12 in the end region of a cylindrical region of reduced cross-section, the lateral surface of a support surface 35 forms. The support surface 35 is in non-detachable connection with a socket 36 , which are integral with the flange 18 and the ring gear 19 is trained. The camshaft 12 has in the transition area to the support surface 35 a paragraph 37 , by means of which during manufacture of the connection between the socket 36 and the camshaft the axial position of the bushing 36 can be specified relative to the camshaft.

While socket 36 and ring gear 19 according to 3 on the same side of the flange 18 namely on the cam 14 are arranged opposite side of the flange are socket 33 and ring gear 19 according to 2 on opposite sides of the flange 18 arranged.

deviant to the illustrated embodiments It may be in the case that it is in the gearbox of the camshaft adjuster is a planetary gear, which is not detachably connected to the camshaft Transmission element act around a bridge, opposite which a planet rotatable is stored.

At the camshaft 12 with or without attachments, gear or flange is preferably one made of steel, cast iron or aluminum, for example in composite construction or as a built camshaft.

The not solvable Components to be connected with the camshaft may initially be prepared separately or finished be and then connected to the camshaft and then optionally be finished. Alternatively, the aforementioned components already in a forming process or original forming process of the camshaft be connected with this.

For the production the non-detachable Connection between camshaft and gear and / or flange can a traction and / or positive engagement are used accordingly the known method for the production of built camshafts, in particular circular circuit method, expansion with a profiled Internal mandrel or push-through ball, hydroforming, rolling or widening by partial rolling.

at a preparation of the compound by hydroforming For example, the flange or the gear as a finished part together with other inserts, in particular cams or bearing seats, be inserted into the mold. Subsequently, the expansion takes place the executed as a pipe Camshaft using high internal pressure due to deformation and optional in combination with special inner contours of the inserts, thereby a frictional connection and / or positive connection arises.

at the use of a press connection or shrink connection, for example the gear can be shrunk onto the camshaft or into a axial bore of the camshaft are pressed. Here can it is a thermal cross-press connection, a shrink or expansion connection or a longitudinal press connection.

In addition to further connection possibilities can prevent rotation by a positive connection, for example by using a polygon shaft, a splined shaft, a hexagonal shaft, a Keyway or the like, respectively. Alternatively or in addition is an axial fuse by force or positive locking possible. This can also be a Screw are used, which is smaller than according to the beginning mentioned prior art and only an axial fuse serves while essential functions taken from the non-detachable connection become.

at one by pouring manufactured camshaft can be in a mold of the flange or a Blank of the gear to be formed while the teeth in retrospect the blank is introduced by machining, for example by means of butting.

Farther can between the camshaft and camshaft adjuster an axial Adapter used become. The connection of the intermediate piece to the camshaft and with the camshaft rotating components of the camshaft adjuster takes place in an analogous manner. The intermediate piece can be cylindrical, cup-shaped or tubular be educated. Furthermore, the intermediate piece, the camshaft or the previously described axial extension in addition to the functions mentioned additional Have functions, in particular as a sensor wheel for sensors serve or markings, a hexagon or a double edge, a cam for a pump or similar exhibit.

10

Phaser

11

driving element

12

camshaft

13

coupling agent

14

cam

15

drilling

16

recess

17

ring section

18

flange

19

ring gear

20

internal gearing

21

Rifle

22

ring gear

23

fuse element

24

needle roller bearings

25

eccentric shaft

26

clutch

27

drilling

28

needle roller bearings

29

axial extension

30

subregion

31

storage area

32

supporting

33

Rifle

34

paragraph

35

supporting

36

Rifle

37

paragraph

38

gearing

39

gearing

Claims (10)

Camshaft drive with a camshaft adjuster ( 10 ), which drives a drivable by a drive means drive element ( 11 ), an actuating unit and a transmission, wherein by means of the transmission, the drive movement of the drive element ( 11 ) on a camshaft ( 12 ) is transferable and in accordance with an actuating movement of the actuator, a relative angle of rotation between the drive element ( 11 ) and camshaft ( 12 ) Is variable, characterized in that a gear (ring gear 19 ) or a web of the camshaft adjuster ( 10 ) not detachable with the camshaft ( 12 ) connected is. Camshaft drive according to claim 1, characterized in that the gear (ring gear 19 ) or the web of a radially to the camshaft ( 12 ) extending flange ( 18 ) is worn. Camshaft drive according to claim 1 or 2, characterized in that - the camshaft ( 12 ) and the gear (ring gear 19 ) or the web, - the camshaft and the flange ( 18 ), - the flange ( 18 ) and the gear (ring gear 19 ) or the web or - the camshaft ( 12 ), the flange ( 18 ) and the gear (ring gear 19 ) or the web are formed integrally with each other. Camshaft drive according to claim 3, characterized in that - the camshaft ( 12 ) and the gear (ring gear 19 ) or the web, - the camshaft and the flange ( 18 ), - the flange ( 18 ) and the gear (ring gear 19 ) or the web or - the camshaft ( 12 ), the flange ( 18 ) and the gear (ring gear 19 ) or the bridge are made by casting, forging or hydroforming. Camshaft drive according to one of the preceding claims, characterized in that the camshaft ( 12 ) has an outer lateral surface which serves as a bearing surface ( 31 ) for a relative to the camshaft ( 12 ) moved component (eccentric shaft 25 ) serves. Camshaft drive according to one of the preceding claims, characterized in that the gear wheel is a ring gear ( 19 ) of an inner eccentric gear. Camshaft drive with a camshaft adjuster, the drive element driven by a drive means ( 11 ), an actuating unit and a transmission, wherein by means of the transmission, the drive movement of the drive element ( 11 ) on a camshaft ( 12 ) is transferable and in accordance with an actuating movement of the actuator, a relative angle of rotation between the drive element ( 11 ) and camshaft ( 12 ) is variable, characterized in that the camshaft ( 12 ) not detachable with an axial extension ( 29 ) is connected, via which a support of a component (eccentric shaft 25 ) of the camshaft adjuster ( 10 ) he follows. Camshaft drive according to claim 7, characterized in that the axial extension ( 29 ) has an outer lateral surface which serves as a bearing surface ( 31 ) for a relative to the camshaft ( 12 ) moved component (eccentric shaft 25 ) serves. Camshaft drive according to claim 7 or 8, characterized in that the axial extension ( 29 ) in an axial recess ( 16 ) of the front side of the camshaft ( 12 ) is used. Camshaft drive according to one of claims 1 to 6 and one of the claims 7 to 9.