DE102006004718A1 - Camshaft adjuster in vane-type construction - Google Patents

Abstract

The invention relates to a vane type camshaft adjuster for an internal combustion engine. Such camshaft adjusters require a seal between an end face of a vane (9) and a lateral surface (6) that is moved relative to the vane (9). According to the state of the art, resiliently supported sealing strips are used for this purpose, which are inserted, for example, into a groove in the end face of the wing (9). According to the invention it is proposed that a sealing element (23) is U-shaped and encompasses the wing (9). A radial preload and a radial elasticity can be structurally specified by the contouring of the sealing element (23). In particular, this provides an option for sealing that is inexpensive to manufacture, requires small tolerances, requires a small number of components and is easy to assemble.

Description

Territory of invention

The The invention relates to a vane-type camshaft adjuster according to the generic term of claim 1.

background the invention

at known camshaft adjusters for internal combustion engines is about a suitable traction means, for example a chain or a toothed belt, a drive movement of a crankshaft to a drive gear transmitted the camshaft adjuster, which is rotatably connected to a stator. In the stator are radially inside of a lateral surface of the stator several pressure chambers formed, which oriented in the circumferential direction by radially inward wing of the stator are limited, extending from the lateral surface of the Stators extend. In the stator, a rotor is arranged, whose lateral surface across from the wings of the stator is sealed by suitable sealing elements and the from the aforementioned lateral surface radially outward oriented wings which, in the region of its end face relative to the lateral surface of the Stators are sealed.

Existing Column between the pressure chambers limiting components can lead to internal and / or external leakage. In the recent past the leakage value is an important performance feature of camshaft phasers become, since this the dimensions, the installation space and / or the weight and the costs necessary additional Motor units such as valves, oil pumps etc. influenced. A reduction in unwanted internal leakage can by narrowing the for the leakage responsible column and / or due to increased friction as a result of an increased Contact pressure in the leakage gap can be achieved. This requires, however a greater accuracy in the manufacture of the components, which can lead to increased production costs. Be in the area of the column additional Used sealing elements, this means an increase in cost and / or an increase in weight for the Phaser. A further increase in the production effort and The cost of production means the production of suitable active surfaces for Integration of the sealing elements, in particular grooves, support surfaces or -vorsprünge etc.

To form an alternative seal between the end face of the wings and the associated lateral surface are made DE 197 15 570 A1 approximately cuboid wing segments known which are inserted with play in the circumferential direction in an axially oriented groove of the rotor. At a standstill, the wing segments also form a clearance radially relative to the lateral surface of the stator, which is bridged radially outwards during operation of the internal combustion engine as a result of the rotation of the rotor and the resulting radially outwardly directed centrifugal force and the movement of the wing segments caused thereby. At the same time minimizing the leakage can be simplified in this way, the production of the wings and rotor and stator, as for a good seal usually required tight tolerances that are disadvantageous in terms of manufacturing effort, can be avoided.

Out DE 39 22 962 A1 It is known to provide the end face of wings with axially oriented grooves in which radial seals are arranged for sealing between the end face of the wing and the associated lateral surface.

On off DE 199 80 580 T1 Known sealing element is arranged in a running in the axial direction, radially outwardly oriented groove in a wing of the stator. Between the bottom of the groove and a sealing strip of the sealing element, a string-like tensioned leaf spring is interposed, which acts on the sealing strip radially inwardly in the direction of the lateral surface of the rotor, whereby a seal is achieved. Corresponding leaf springs preloaded sealing strips are arranged in grooves of the wings.

DE 197 40 215 A1 discloses a gasket made of a PPS resin (polyphenylene sulfide) as a base material provided with an inorganic filler harder than the PPS resin. The seal is biased by a leaf spring and receives a centrifugal force radially outward to an associated lateral surface. As the base material of the gasket, other synthetic resin may be used instead of the PPS resin, for example, polyamide-imide, polyimide, polyether-ether-ketone, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyamide, polyoxymethylene, phenol or teflon.

Farther are known by the company Delphi plastic sealing strips, which have two integrated rubber lips through which the sealing strips resiliently supported can be.

task the invention

• – der Herstellungskosten,
• – der Dichtfunktion,
• – des Bauraums,
• – der Montage,
• – des Gewichts und
• – der Zuverlässigkeit

eine alternative Ausgestaltung eines Nockenwellenverstellers in Flügelzellenbauweise für eine Brennkraftmaschine vorzuschlagen.The invention is based on the object, in particular taking into account

• - the production costs,
• - the sealing function,
• - the installation space,
• - the assembly,
• - the weight and
• - reliability

to propose an alternative embodiment of a vane-type camshaft adjuster for an internal combustion engine.

Summary the invention

According to the invention Problem solved by the features of independent claim 1. Further Embodiments of the invention will become apparent according to the dependent claims 2-9.

Of the The present invention is initially the Recognition that resiliently supported sealing strips accordingly the prior art u. U. to increased leakage in a center position of the Lead rotor, in which the rotor with the sealing strip under an oscillating Pressure load between the opposite pressure chambers are can. This can lead to a tilting of the sealing strip in one Groove of the rotor come, resulting in increased friction all the way to a Clamp the sealing strips can cause leakage as a result of a lack of sealing in the Area of the groove receiving the sealing strip.

Farther the invention has recognized that a sealing strip with a sealing strip body and additional Spring elements, for example leaf springs or resilient rubber lips, represent a complex component, which increased costs and increased weight can cause.

When The problem with the invention for the solutions mentioned in accordance with the prior Technique also the feeder of a sealing strip associated spring element with a precise Orientation to a groove receiving the sealing strip during assembly the components of the camshaft adjuster detected. Are several sealing strips required, with an increased Number of sealing strips also increases the number of column, thereby the existing risk of leakage with every other sealing strip reproduced.

In accordance with the invention the sealing element is a U-shaped Basic cross-section. Under basic cross-section is understood here, that such a cross-sectional description only in the first, rough approximation should apply. In particular, angle deviations of up to 5 °, 10 ° or 15 ° with respect to a U-shape in the rough and / or local deviations in the form of curvatures, projections Waves and ä. across from a U-shape are possible according to the respective requirements.

Of the U-shaped Basic cross section is with a base leg and two side legs formed in the installed state in the camshaft adjuster the Ground leg about oriented in the circumferential direction, while the side legs approximately radially are oriented. The U-shaped Basic cross-section surrounds the wing. In this case, the encompassing can take place such that an entire end region of the grand piano from the outside is encompassed. Alternatively, it is possible that the wing is frontal Has grooves into which the side legs enter.

By the embodiment of the invention can be avoided that the radial extent of the wing with close tolerance to the diameter of the front side with the wing in operative connection passing lateral surface must be adjusted. Also the surface design of the face of the wing can u. U. independently from a desired one Sliding connection between wings and lateral surface be made. Rather, the wing can only provide a body, the pressure chambers limited and transmits forces to the Serve adjustment of the camshaft adjuster. Instead of the end face of the wing For example, the base leg forms the contact surface and so that the sealing surface with the lateral surface out. For the contact area of the base leg, in particular the entire Sealing element, can specifically a suitable material for a desired contact and sealing action selected become.

• – Bereitstellung einer Dichtfläche mit der Mantelfläche,
• – Bereitstellung mindestens einer Führungsfläche für radiale Bewegungen des Dichtelements gegenüber dem Flügel,
• – Festsetzung anderer Freiheitsgrade des Dichtelements gegenüber dem Flügel, insbesondere Vermeidung einer Verkippung des Dichtelements mit im Bereich des Grundschenkels auftretender Reibung und/oder Druckdifferenzen in unterschiedlichen Druckräumen,
• – Bereitstellung einer spielbehafteten oder spielfreien Abstützung des Dichtelements gegenüber dem Flügel in Umfangsrichtung,
• – Bereitstellung einer Federwirkung zur radialen Anprssung des Dichtelements an die Mantelfläche,
• – Gewährleistung einer Anpassung an Fertigungstoleranzen und u. U. Ermöglichung vergrößerter Toleranzen,
• – Bereitstellung einer verschleißfesten Oberfläche für relativ zueinander bewegte Kontaktpartner.

According to the invention, different functions can be distributed on the base leg of the U-shaped base cross section on the one hand and the side legs on the other hand. Possible functions to be fulfilled alternatively or cumulatively by the base leg and the side legs are as follows:

• Providing a sealing surface with the lateral surface,
• Providing at least one guide surface for radial movements of the sealing element relative to the wing,
• Fixing other degrees of freedom of the sealing element with respect to the wing, in particular avoiding tilting of the sealing element with friction occurring in the region of the base limb and / or pressure differences in different pressure chambers,
• Providing a play-bearing or play-free support of the sealing element with respect to the wing in the circumferential direction,
• Provision of a spring action for the radial contact of the sealing element against the lateral surface,
• - ensuring an adaptation to manufacturing tolerances and u. U. Enabling increased tolerances,
• - Providing a wear-resistant surface for relatively moving contact partner.

For a provision of the aforementioned spring action, there are many possibilities: at For example, a radial contact surface between the sealing element and wing can be designed to be elastic, in particular by interposing a spring element and / or an elastic coating. Here, the wing-facing contact surface of the base leg and / or a side facing away from the base leg end side of the side leg can be elastically supported as previously explained. Further possibilities for providing the spring action may consist in an elastic design of a main body of the sealing element itself, wherein the resilient action may be effected by an elastic deformation of the base body.

The guide the sealing element in the radial direction and the support in the circumferential direction is preferably by radially oriented surfaces, grooves, projections or Webs of the grand piano and appropriate contact or leadership areas provided the sealing element.

to Providing the sealing effect can be the contact areas of the Seal element with the associated lateral surface to be flat or curved as well as with the main body the sealing element, a coating or an additional body formed be. Several circumferentially connected contact areas between the sealing element and the lateral surface may also be provided like any sealing lips.

ever after designing the radial guide between Sealing element and wings, especially depending on the friction acting in the radial direction, can additional or alternatively to the resilient generation of a contact pressure between the sealing element and lateral surface a centrifugal component exploited during rotation of the sealing element associated wing become.

According to one Another embodiment of the invention, the base leg is in radial Direction elastic, causing the base leg at least a part the necessary contact pressure for the sealing element to the lateral surface for one Inducing one Provides sealing effect and an adjustment of radial manufacturing tolerances can make.

For one another camshaft adjuster according to the invention has the base leg of the sealing element with a U-shaped base cross-section a minimum and two maxima. The elasticity in the radial direction is provided by the distance of the minimum from at least a maximum under elastic loading of the base leg (or a basic body the same) changeable is. It may be advantageous if a support between Sealing element and wing in Area of the minimum takes place while the support the sealing element on the lateral surface for generating the sealing effect in the region of a maximum, preferably both maxima for the generation of two successively connected sealing surfaces, takes place.

According to one Another embodiment of the invention, the wing between the elastic flared side legs of the U-shaped base profile of the sealing element clamped. By clamping can be an automatic adjustment take place at any manufacturing tolerances for the side surfaces of the wing. At the same time, a game between sealing element and wing, at least in the circumferential direction, be avoided. About the design of the contact pressure On the one hand, the support of the Sealing element be specified structurally in the circumferential direction. On the other hand frictional forces for one Displacement of the sealing element in the radial direction structurally predetermined become.

at consideration The local structure allows the sealing element in a scale, in which deviations from the U-shaped Basic form exaggerated are shown as W-shaped be designated, wherein the lower extremities of the W the two maxima represent, in the region of which the sealing element rests against the lateral surface, while the middle upper extremity of the W forms the minimum, in the area of which a support of the Sealing element takes place on the front side of the wing. The outside Side legs of the W are extended formed and enter into suitable grooves of the wing or engage around side surfaces of the Wing.

For a special simple embodiment of the invention, the sealing element with a Formed spring steel, which thus provides a body, which in itself an elasticity features, the for a clamping of the wing between the side legs and / or for providing the radial elasticity and thus used the contact pressure of the sealing element to the lateral surface can be.

In alternative or cumulative embodiment is the sealing element formed with a resilient plastic. For example the resilient plastic the body of the sealing element ready or a suitable coating, for example a base body Spring steel.

Advantageous developments of the invention will become apparent from the claims, the description and the drawings. The advantages of features and of combinations of several features mentioned in the introduction to the description are merely exemplary, without them necessarily having to be achieved by embodiments according to the invention. Further features are the drawings - in particular the illustrated geometry and the relative dimensions of several components to each other and their relative arrangement and operative connection - refer. The combination of features of different embodiments of the invention or of features of different claims is also possible deviating from the chosen relationships of the claims and is hereby stimulated. This also applies to those features which are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different claims. Likewise, in the claims listed features for further embodiments of the invention can be omitted.

short Description of 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 camshaft adjuster according to the prior art;

2 a specific for a camshaft adjuster sealing element according to the invention in cross section;

3 the sealing element according to 2 in spatial representation;

4 A first embodiment of a No ckenwellenverstellers invention in cross section;

5 the embodiment of the camshaft adjuster according to the invention 4 in spatial representation,

6 a detail of the sealing area between the wing, sealing element and lateral surface for a camshaft adjuster according to the invention and

7 a detail accordingly 6 for an alternative embodiment of a sealing element with a base body and two coatings.

Full Description of the invention

1 shows a camshaft adjuster 1 for an internal combustion engine according to the prior art. In the camshaft adjuster 1 is a rotor 2 according to a hydraulic loading against a stator 3 around a longitudinal axis 4 , which according to the presentation 1 oriented vertically to the plane of the drawing, swiveling. The rotor 2 is rotatably associated with a camshaft, while the stator 3 a drive wheel 5 carries, which is in drive connection with a crankshaft of the internal combustion engine.

The stator has, starting from an otherwise approximately cylindrical inner circumferential surface 6 radially inwardly oriented wings 7 , The rotor 2 has an external cylindrical surface 8th , the radially outwardly oriented wings 9 wearing. Between adjacent wings 7 are each pressure chambers 10 formed by the wings 9 in opposite pressure chambers 11 . 12 be split. The wings 7 (respectively. 9 ) each have side surfaces 13 . 14 (respectively. 15 . 16 ). The pressure chambers 11 are circumferentially bounded by the side surface 13 of the grand piano 7 as well as the side surface 15 of the grand piano 9 and in the radial direction through the lateral surface 6 of the stator 3 and the lateral surface 8th of the rotor 2 , The pressure room 12 is in the circumferential direction be limited by the side surface 16 of the grand piano 9 and the side surface 14 of the grand piano 7 and in the radial direction through the lateral surface 6 of the stator 3 and the lateral surface 8th of the rotor 2 ,

A sufficiently closed pressure chamber to ensure pressure differences in the pressure chambers 11 . 12 To provide, is a seal on the one hand between an end face 17 of the grand piano 9 of the rotor 2 opposite the lateral surface 6 as well as the face 18 of the grand piano 7 of the stator 3 opposite the lateral surface 8th required. According to a solution known from the prior art, such a sealing takes place in that the end faces 17 . 18 axial grooves 19 . 20 own, in which an elastic sealing element or a sealing strip 21 . 22 is used.

2 and 3 show a sealing element 23 for use in a camshaft adjuster according to the invention. The sealing element 23 is in its first cross-section as a U-shaped designate with a base leg 24 and two side legs 25 . 26 , In the transition area of the base leg 24 to the side legs 25 . 26 are rounding off 27 . 28 intended. The base leg 24 is formed slightly curved radially inwardly when extending in the direction of the Unfang, so that the outside of the base leg 24 is concave. In the area of the base leg 24 are maxima 29 . 30 formed as well as approximately in the middle, on which the maxima 29 . 30 opposite inside a minimum 31 , The side legs 25 . 26 converge starting from the base leg 24 towards each other and are substantially rectilinear with a slight bend outward in their end regions. The sealing element 23 has a constant thickness in cross section and is formed in particular of a semi-finished product in the form of a spring steel sheet or of an elastic plastic.

4 and 5 show the sealing element 23 in its installed state, for the sealing element radially from the outside in each case a wing 9 of the rotor 2 surrounds, leaving the base leg 24 at the frontal area 17 abuts and the side legs 25 . 26 on the side surfaces 15 . 16 issue. On the wing 9 opposite side is the base leg 24 on the lateral surface 6 at.

6 shows in detail the formation of the contact areas between the sealing element 23 and wings 9 as well as lateral surface 6 : As a result of contouring of the base leg 24 with the maxima 29 . 30 lies the sealing element 23 in the range of maxima 29 . 30 at contact areas 32 . 33 the lateral surface 6 on, while between the maxima 29 . 30 a radial gap 34 between sealing element 23 and lateral surface 6 is formed. In the area of the minimum 31 lies the sealing element 23 at a contact area 35 the face 17 at. In the in 6 shown installation state, the sealing element is biased such that compared to the in the 2 and 3 illustrated voltage-free state the maxima 29 . 30 due to elastic deformation of the sealing element 23 in the direction of the minimum 31 are deformed. According to the elastic loading results in a radial contact pressure of the sealing element 23 both to the contact areas 32 . 33 as well as to the contact area 35 , The side legs 25 . 26 lie large area on the side surfaces 15 . 16 of the grand piano 9 on, which is due to an elastic loading of the side legs 25 . 26 can give a contact force.

In 4 it can be seen that the rotor 2 wing 9 may have, which have different thicknesses, ie extensions in the circumferential direction, in which case the length of the base leg 24 of the sealing element 23 to the extent of the associated wing 9 is adjusted in the circumferential direction. Alternatively or additionally, in a corresponding manner, the wings 7 of the stator 3 with a sealing element 23 be provided.

In the event that the lateral surface 6 Has depressions, the maxima 29 . 30 enter for selected positions in these recesses, which are formed in a simple way detents, for increased actuating forces under elastic deformation of the sealing element 23 can be overcome. Due to the contour area in the area of the maxima 29 . 30 as well as the design of the bevels or boundaries of the recesses, the force control curve, which is required to overcome the detents, be given constructive.

The sealing element 23 Can be made of spring steel or elastic plastic.

As a result of the two maxima 29 . 30 arise in succession switched contact areas 32 . 33 , which ensure a redundant sealing effect. By deviant, wave-like design of the base leg 24 Any number of such contact areas can be connected in series.

7 shows an alternative embodiment of a sealing element 23 , which in this case with a basic body 36 and a radially outer coating 37 and a radially inner coating 38 or corresponding elastic auxiliary bodies, spring bodies or sealing bodies is formed. In this case, the main body 36 approximately U-shaped, with the side legs 25 . 26 as well as the base leg 24 may be formed substantially straight. The radially outer side of the base leg 24 is extensive with the coating 37 provided, which serves a seal, providing a radial elasticity and / or ensuring wear resistance. The on the inside of the base leg 24 arranged coating 38 serves to provide a radial elasticity to ensure a contact force between the sealing element 23 and lateral surface 6 and / or a tolerance compensation. The coatings 37 . 38 are on the body 36 sprayed or injected into this or as separate components with the main body 36 connected, in particular inserted in this, glued or vulcanized to this.

The main body 36 is made in particular of spring steel, while the coatings 37 . 38 may be formed with another material or material, in particular a plastic or rubber coating or a wear-resistant chemical / galvanic coating of the body.

The sealing element 23 can be made from an endless profile by cutting and cutting to a certain length, which allows a particularly cost-effective production.

For a mounting of the sealing element can first in an automatic assembly the sealing element 23 in the axial direction or radially inward on the wing 9 be joined. The sealing elements 23 can hereby be moved axially by means of a conical mounting sleeve, are biased and mounted axially in the given space.

• – Funktionsverbesserung durch integrierte Feder- und Dichtfunktion in einem einzigen Bauteil,
• – Verringerung der Zahl der Leckagespalte auf ein Minimum infolge der Reduzierung der Bauteilzahl,
• – Kostenneutralität oder Kosten reduzierende Wirkung durch den Entfall einer Dichtleiste, einer Blattfeder und durch Vereinfachung der Zuführung bei der Montage,
• – vereinfachte Zuführung des Dichtelements 23 bei der Montage im Vergleich zu einer Lösung mit einer elastisch abgestützten Dichtleiste aufgrund des besseren Handlings durch größere Abmaße und eine reduzierte Zahl der zu montierenden Bauteile,
• – Wartungsfreiheit,
• – Reduktion des Verstellergewichts durch Entfall der Dichtleisten, Blattfedern und eines bestimmten Teil des Flügels,
• – vorteilhafte Gestaltung des Bauraums des Verstellers – auch eine Integration des veränderten Dichtelements in eine ansonsten übliche Gestaltung eines Nockenwellenverstellers ist ohne große Anpassungen möglich.

The solution according to the invention offers, in particular, the following alternative or cumulative advantages:

• - Functional improvement through integrated spring and sealing function in a single component,
• - Reduce the number of leakage gaps to one Minimum due to the reduction in the number of components,
• Cost neutrality or cost-reducing effect by the elimination of a sealing strip, a leaf spring and by simplifying the feeding during assembly,
• - Simplified feeding of the sealing element 23 during assembly compared to a solution with a resiliently supported sealing strip due to the better handling due to larger dimensions and a reduced number of components to be mounted,
• - maintenance freedom,
• Reduction of the adjuster weight by omission of the sealing strips, leaf springs and a certain part of the wing,
• - Advantageous design of the installation space of the adjuster - Even an integration of the modified sealing element in an otherwise conventional design of a camshaft adjuster is possible without major adjustments.

1

Phaser

2

rotor

3

stator

4

longitudinal axis

5

drive wheel

6

Lateral surface of the stator

7

Wing stator

8th

Lateral surface rotor

9

Wing rotor

10

pressure chamber

11

pressure chamber

12

pressure chamber

13

side surface

14

side surface

15

side surface

16

side surface

17

Face rotor

18

End face stator

19

groove

20

groove

21

sealing element

22

sealing element

23

sealing element

24

base leg

25

side leg

26

side leg

27

rounding off

28

rounding off

29

maximum

30

maximum

31

minimum

32

contact area

33

contact area

34

gap

35

contact area

36

body

37

coating

38

coating

Claims (9)

Vane-type camshaft adjuster with a stator ( 3 ) and one relative to the stator ( 3 ) rotatable rotor ( 2 ) and at least two between stator ( 3 ) and rotor ( 2 ) pressure chambers ( 11 . 12 ), which by a radially oriented wing ( 7 ; 9 ) are separated from each other, the wing ( 7 ; 9 ) an end face ( 17 ; 18 ), which opposite a lateral surface ( 6 ; 8th ) is movable and is sealed by a sealing element, characterized in that the sealing element ( 23 ) has a U-shaped base cross section with an approximately circumferentially oriented base leg ( 24 ) and two radially oriented side legs ( 25 . 26 ), wherein the U-shaped basic cross-section of the wing ( 7 ; 9 ) surrounds. Camshaft adjuster according to claim 1, characterized in that the base leg ( 24 ) is elastic in the radial direction. Camshaft adjuster according to claim 2, characterized in that the base leg ( 24 ) a minimum ( 31 ) as well as two maxima ( 29 . 30 ) and the distance of the minimum ( 31 ) and of at least one maximum ( 29 . 30 ) under elastic loading of the base leg ( 24 ) is changeable. Camshaft adjuster according to claim 3, characterized in that the two maxima ( 29 . 30 ) under elastic prestress on the lateral surface ( 6 ; 8th ) issue. Camshaft adjuster according to one of the preceding claims, characterized in that between the elastically flared side legs ( 25 . 26 ) the wing ( 7 ; 9 ) is clamped. Camshaft adjuster according to one of the preceding claims, characterized in that the sealing element ( 23 ) approximately W-shaped with extended side legs ( 25 . 26 ) is trained. Camshaft adjuster according to one of the preceding claims, characterized in that the sealing element ( 23 ) is formed with a spring steel. Camshaft adjuster after one of the above hergehen claims, characterized in that the sealing element ( 23 ) is formed with a resilient plastic. Camshaft adjuster according to one of the preceding claims, characterized in that the sealing element ( 23 ) a basic body ( 36 ) and at least one coating ( 37 . 38 ) having.