EP2604817B1 - Camshaft adjuster - Google Patents

Description

Field of the invention

The invention relates to a camshaft adjuster.

Background of the invention

Camshaft adjusters are used in internal combustion engines to vary the timing of the combustion chamber valves in order to make the phase relation between the crankshaft and the camshaft in a defined angular range, between a maximum early and a maximum late position variable. Adjusting the timing to the current load and speed reduces fuel consumption and emissions. For this purpose, camshaft adjuster are integrated into a drive train, via which a torque is transmitted from the crankshaft to the camshaft. This drive train may be formed for example as a belt, chain or gear drive.

In a hydraulic camshaft adjuster, the output element and the drive element form one or more pairs of mutually acting pressure chambers, which can be acted upon by hydraulic fluid. The drive element and the output element are arranged coaxially. By filling and emptying individual pressure chambers, a relative movement between the drive element and the output element is generated. The rotationally acting on between the drive element and the output element spring urges the drive element relative to the output element in an advantageous direction. This advantage direction can be the same or opposite to the direction of rotation.

One type of hydraulic phaser is the vane phaser. The vane cell adjuster comprises a stator, a rotor and a drive wheel with an external toothing. The rotor is designed as a driven element usually rotatably connected to the camshaft. The drive element includes the stator and the drive wheel. The stator and the drive wheel are rotatably connected to each other or alternatively formed integrally with each other. The rotor is coaxial with the stator and located inside the stator. The rotor and the stator are characterized by their, radially extending wings, oppositely acting oil chambers, which are acted upon by oil pressure and allow relative rotation between the stator and the rotor. The wings are either formed integrally with the rotor or the stator or arranged as "inserted wings" in designated grooves of the rotor or the stator. Furthermore, the vane cell adjusters have various sealing lids. The stator and the sealing lids are secured together via several screw connections.

Another type of hydraulic phaser is the axial piston phaser. Here, a displacement element is axially displaced via oil pressure, which generates a helical gear teeth relative rotation between a drive element and an output element.

Another design of a camshaft adjuster is the electromechanical camshaft adjuster, which has a three-shaft gear (for example, a planetary gear). One of the shafts forms the drive element and a second shaft forms the output element. About the third wave, the system by means of an adjusting device, such as an electric motor or a brake, rotational energy supplied or removed from the system. A spring may additionally be arranged, which supports or returns the relative rotation between the drive element and output element.

The DE 10 2006 002 993 A1 shows a phaser with a sprocket, a rotor, a housing and a spring. The housing and the rotor form the working chambers for relative rotation. The sprocket is rotatably connected to the housing. The spring is arranged outside of the housing and is protected by an additional spring cover, which is connected to the sprocket, against external contamination and thus against life shortening foreign influence as far as possible. The rotor has a pin passing through the housing which provides support for a spring base of the spring.

Summary of the invention

The object of the invention is to provide a camshaft adjuster, which increases the life of the spring.

According to the invention, this object is solved by the features of claim 1.

This ensures that the contact between the spring wire of the spring and the spring bearing is lubricated targeted so that the wear is further minimized. For this purpose, lubricant depots are provided which can provide and provide lubricant for the contact point. Thus, a resilient lubricant film builds up between the spring wire of the spring and the spring bearing, which minimizes the sliding friction resulting from the relative movement between the spring wire and the spring bearing. The minimized sliding friction leads to less abrasion of the spring bearing and / or on the spring wire, which is significantly increased just at load limit near dimensioning of spring wire and spring bearing life of the spring and / or the spring bearing.

The resulting by the minimized wear particles are collected by the lubricant depot and transported away from the contact point between the spring wire and spring bearing. The formation of a suspension Particles and lubricants at the point of contact, which would further increase wear as time progresses, are avoided. The particles are either discharged from the contact between the spring wire and the spring bearing to the environment, or can collect in the lubricant reservoir at a remote location to the lubricant film, for example, at the bottom of the depot.

In one embodiment of the invention, the lubricant reservoir is defined as a region between a two-line contact of the spring wire with the associated spring bearing. The area between the two line contacts has a distance of the spring to the spring bearing. The resulting space may already contain lubricant or lubricant can be supplied to it. In reality, the term two-line contact also includes a two-point contact which, as a result of the relative movement of the two contact partners, converts into a two-line contact after the operating time has progressed. For example, a planar design of the spring bearing with a curvature of a spring coil of any cross-section form such a two-line contact. Alternatively, the planar design of the spring bearing may have a curvature many times smaller than that of the spring coil. Advantageously, it can thus be transverse to the winding direction, or to the course of the spring wire, e.g. Liquid lubricant to be supplied to the lubricant depot. Thus, fresh lubricant is provided for the lubricant film and at the same time the particles still produced by the minimized wear are removed from the lubricant reservoir or rinsed out.

In an advantageous embodiment, the lubricant reservoir is designed as a pocket. As a pocket any form of well is understood, which is clearly delimited from the lateral surface of the spring bearing and also has a depth. The shape of the demarcation can be square, rectangular, triangular, polygonal, oval and / or circular and their border closed or opened. Such a bag may be filled with liquid lubricant or filled during operation. Alternatively, the bag already solid lubricant, eg graphite. As solid lubricants metals with good sliding properties can be used in the bag.

In one embodiment of the invention, the lubricant reservoir is formed as a groove. A groove resembles the bag's definition and also has the delimitation and the depth, but with the peculiarity that one dimension of the delineation, the length, is many times greater than the other, and thus defines the direction of the orientation. Furthermore, the boundary of the boundary does not have to be self-contained. For example, the border of the groove is open at a shorter demarcation section. Depending on the geometry of the tool, the cross-section of the groove can take on any shape for producing the groove.

The orientation of the groove may be longitudinal, transverse or oblique relative to the direction of extension of the spring wire of the spring. The length of the groove is advantageously not limited to the wire thickness of the spring, but protrudes on both sides or on one side beyond the spring wire. Thus, it is advantageously possible to add fresh lubricant in liquid form or to remove used lubricant. A plurality of grooves distributed over the area of contact of the spring to the spring bearing is advantageous because the reliability of a single lubrication is distributed to a plurality of lubricant depots.

Advantageously, remains in the arrangement of a groove on the spring bearing sufficient lateral surface of the spring bearing itself, whose allowable load is supported by the lubricant and its wear is minimized.

In a particularly preferred embodiment, the groove formed as a lubricant reservoir is arranged transversely or obliquely to the spring wire of the spring. Transverse is almost an angle of 90 ° between the course of the spring wire and the longitudinal direction of the groove. An angle of almost 0 ° corresponds to the term longitudinal and obliquely, each angle between transverse and longitudinal to consider. In contrast to the longitudinal orientation, it is advantageously an oblique or To select transverse profile of the groove, because then the effect is minimized that the lubricant is displaced from the groove by the relative movement and the lubricant depot no lubricant is stored more.

In a preferred embodiment, the trained as a groove lubricant reservoir is formed circumferentially. Circumferential grooves are particularly suitable for spring bearings with rotationally symmetrical shape. Circumferential grooves may be partially circumferential or completely circumferential. A completely circumferential groove, formed as a groove, combines their beginning and end together. Advantageously, the width of the groove is smaller than that of the spring wire, so that sufficient lateral surface of the spring bearing remains outside the groove. Ideally, the groove is disposed within the projected onto the spring bearing surface of the spring wire.

In a further embodiment of the invention, the lubricant reservoir is formed as a slot. The slot extends, as a deep groove, through the wall of the spring bearing. Advantageously, the particles resulting from the minimized wear can be better dissipated or flushed out. The width of the slot is sized so that liquid lubricant can be stored within the slot.

In one embodiment of the invention, the spring bearing is designed as a pin. The pin can be rotationally symmetrical shape. Rotationally symmetrical pins as a spring bearing can be pins, hub sections or studs formed integrally on the drive element or driven element. In addition, pins may have a stepped diameter for spring mounting. Advantageously, designed as a stepped diameter pins have an implied stop for the spring wire transverse to the direction of extension of the spring wire, so that slippage of the spring wire on the spring bearing is largely counteracted. For example, such trained as a remote diameter pin can be arranged at the free end of a mounting screw and use for spring mounting. at the same time the pins on the aforementioned training of the lubricant depot.

In an advantageous embodiment, the lubricant reservoir is produced by forming. A manufactured by forming lubricant depot has an increased strength, which has a particularly advantageous effect on the minimization of the wear behavior of the bearing. At the same time, smoothed surfaces of the bearing are achieved, which further minimize abrasion.

In a preferred embodiment of the invention, the lubricant depot is designed as a solid lubricant body. This solid lubricant can in a recording, such as a groove mentioned above, bag or similar. be introduced and remain there over the service life of the camshaft adjuster. Solid lubricants may be metals with good sliding properties, graphite, carburized by case hardening, or coatings. The lubricant body as a lubricant reservoir may be formed either as a component separate from the spring mounting, e.g. be formed as a sleeve, ring, plate, or as integrally formed with the spring bearing lubricant depot. This training can be extended by the preceding materials and / or training forms.

The arrangement of a lubricant reservoir in the contact point between spring wire and spring bearing increases the life of spring and spring bearing and minimizes friction in the contact point.

Brief description of the drawings

Embodiments of the invention are illustrated in the figures.

Fig. 1

einen Schnitt durch einen Nockenwellenversteller mit dem erfindungsgemäßen Schmiermitteldepot,

Fig. 2

eine Detailansicht des Schmiermitteldepots nach Fig. 1,

Fig. 3

eine erste, alternative Ausbildung des Schmiermitteldepots nach Fig. 2,

Fig. 4

eine zweite, alternative Ausbildung des Schmiermitteldepots nach Fig. 2,

Fig. 5

eine dritte, alternative Ausbildung des Schmiermitteldepots nach Fig. 2,

Fig. 6

eine vierte, alternative Ausbildung des Schmiermitteldepots nach Fig. 2 und

Fig. 7

eine fünfte, alternative Ausbildung des Schmiermitteldepots nach Fig. 2.

Show it:

Fig. 1

a section through a camshaft adjuster with the lubricant depot according to the invention,

Fig. 2

a detailed view of the lubricant depot after Fig. 1 .

Fig. 3

a first, alternative embodiment of the lubricant depot after Fig. 2 .

Fig. 4

a second, alternative embodiment of the lubricant depot after Fig. 2 .

Fig. 5

a third, alternative embodiment of the lubricant depot after Fig. 2 .

Fig. 6

a fourth, alternative embodiment of the lubricant depot after Fig. 2 and

Fig. 7

a fifth, alternative training of the lubricant depot after Fig. 2 ,

Detailed description of the drawings

Fig. 1 shows a section through a camshaft adjuster 1 with the lubricant depot 6 according to the invention. The function and structure of the camshaft adjuster 1, in particular in vane-type construction, with the drive element 2 and the output element 3 is sufficiently known from the prior art. This camshaft adjuster 1 is provided with a spring 4, which supports the relative rotation between the drive element 2 and driven element 3 in at least one direction of rotation. The spring 4 is mounted by means of spring bearings 5 of the drive element 2 and the driven element 3. The spring bearings 5 are firmly connected to the drive element 2 and the output element 3, respectively.

In this embodiment, a screw 15, this spring bearing 5. The screw 15 extends through an opening 16 of the drive element 2 and connects the side cover 17 with the drive element 2 rotatably with each other. For this purpose, a nut 18 is anchored in one of the side cover 17, which has the matching thread for the screw 15. At the end facing away from the screw head of the screw 15, a pin 9 of the screw 15 is formed. The pin 9 has a smaller diameter than the thread of the screw 15 and is rotationally symmetrical. The pin 9 as a spring bearing 5 is a plurality, extending in the axial direction 19 and provided on the circumference of the pin 9 distributed grooves 7. The grooves 7 are formed as lubricant depots 6. Further details of the spring bearing 5 follow in the Fig. 2 ,

Fig. 2 shows a detailed view of the lubricant reservoir 6 after Fig. 1 , The trained as lubricant depots 6 grooves 7 are distributed uniformly over the circumference of the pin 9. Advantageously, by this distribution, a separate alignment of the grooves 7 for contact between the spring wire 10 and spring mounting 5 after screwing the screw 15 into the nut 18 is not necessary. The grooves 7 are formed open at the free end of the pin 9 in the axial direction 19. The lubricant depots 6 are arranged, in particular in contact between the spring wire 10 of the spring 4 and the spring bearing 5.

In these lubricant depots 6 oil or grease is stored, which lubricates the contact between spring wire 10 and spring bearing 5. As an alternative to oil or grease, solid lubricants, e.g. Graphite, to be stored. Either the lubricants stored in the lubricant reservoir 6 have been introduced before the assembly of the camshaft adjuster 1 or the lubricant reservoir 6 is provided for storage of leakage oil of the camshaft adjuster 1 during operation.

Instead of a screw 15, the pin 9 may be formed by a pin or in one piece with one of the side cover 17, the nut 18, the drive element 2 or the driven element 3. The aforementioned difference in diameter between pins 9 and, for example, the screw 15 can be omitted. Advantageously, however, a stop for the spring wire 10 in the axial direction 19 is formed by the difference in diameter.

Fig. 3 shows a first alternative embodiment of the lubricant reservoir 6 after Fig. 2 , Here, the grooves 7 formed as lubricant depots 6 are formed in the circumferential direction about the axis of symmetry 20 of the pin 9 and the spring bearing 5. Two spaced from each other in the axial direction 19 grooves 7 provide the lubricant reservoir 6 in the contact area between spring wire 10 and spring bearing 5. The grooves 7 may have mutually different cross-sectional shapes, or, as shown in the embodiment, have the same cross-sectional shape. In the exemplary embodiment is clearly visible that the contact length between spring wire 10 and spring bearing 5 in the axial direction 19 is indeed interrupted by the grooves 7, however, the load on the peripheral surface of the spring bearing 5 and the lubricant in the lubricant reservoir 6 is distributed, which is a particularly advantageous lubrication and thereby increasing the carrying capacity and life has the consequence. As already in Fig. 2 mentioned, the lubricant may be introduced prior to assembly or during operation.

Fig. 4 shows a second alternative embodiment of the lubricant reservoir 6 after Fig. 2 , This lubricant reservoir 6 is designed as a pocket 8. The circumferential surface of the pin 9 and the spring bearing 5 is deviating from the original peripheral surface to the symmetry axis 20, so that a kind of trough or pocket 8 is formed. This pocket 8 has the lubricant reservoir 6. Preferably, this pocket 8 is formed on a pin or in one piece with the peripheral components formed pin 9. Training on a screw 15 proves to be disadvantageous in that when screwing the screw 15, the orientation of the pocket 8 must be ensured for contact with the spring wire 10. As already in Fig. 2 mentioned, the lubricant may be introduced prior to assembly or during operation.

Fig. 5 shows a third alternative embodiment of the lubricant reservoir 6 after Fig. 2 , Here, the spring bearing 5 is formed as a square. Various polygonal shapes are conceivable. The lubricant reservoir 6 is formed as a region 12 between a two-line contact 13. The two-line contact 13 is formed by the curvature of the spring wire 10 and the planar design of the spring bearing 5. The area 12 of the two-line contact 13 is formed by the curvature of the spring wire 10 as a cavity in the lubricant is stored. As already in Fig. 2 mentioned, the lubricant may be introduced prior to assembly or during operation.

Fig. 6 shows a fourth, alternative embodiment of the lubricant reservoir 6 after Fig. 2 , The lubricant reservoir 6 is formed as a slot 11 of the spring bearing 5. The slot 11 extends radially through the entire spring bearing 5 therethrough. The orientation of the slot 11 to the spring wire 10 is selected so that an open side of the slot 11 facing the spring wire 10 in contact between spring wire 10 and spring bearing 5. As already in Fig. 2 mentioned, the lubricant may be introduced prior to assembly or during operation.

Fig. 7 shows a fifth, alternative embodiment of the lubricant reservoir 6 after Fig. 2 , Between the spring bearing 5 and the spring wire 10, an additional, the lubricant reservoir 6 exhibiting component 21 is arranged. This here annular member 21 has a larger diameter than the spring bearing 5, which is designed as a rotationally symmetrical pin 9. By resulting from the structure favorable curvature of the component 21 to the curvature of the spring wire 10, the Hertzian stresses are minimized. At the same time, the Hertzian stresses between the component 21 and the spring bearing 5 are minimized due to the in turn favorable curvatures of spring mounting 5 and component 21. The component 21 may advantageously have solid lubricant. For this, materials such as graphite or metals with good sliding properties, such as non-ferrous metals, are suitable. Another variant is to produce the component 21 from a sintered material and to infiltrate with the lubricant.

List of reference numbers

1. 1) Camshaft adjuster
2. 2) drive element
3. 3) output element
4. 4) spring
5. 5) Spring mounting
6. 6) Lubricant depot
7. 7) groove
8. 8) bag
9. 9) pins
10. 10) spring wire
11. 11) slot
12. 12) area
13. 13) Two-line contact
14. 14) solid lubricant
15. 15) screw
16. 16) Opening
17. 17) side cover
18. 18) Mother
19. 19) axial direction
20. 20) axis of symmetry
21. 21) component

Claims (10)

1. Camshaft adjuster (1) having a drive element (2), an output element (3) and a spring (4), it being possible for the drive element (2) and the output element (3) to be rotated relative to one another, the spring (4) being fixed by way of a spring mounting (5) of the drive element (2) and a spring mounting (5) of the output element (3), the spring (4) assisting the relative rotation between the drive element (2) and the output element (3), characterized in that a lubricant reservoir (6) is provided between the spring wire (10) of the spring (4) and its spring mountings (5), in order to lubricate the contact between the spring wire (10) and the spring mounting (5).
2. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is defined as a region (12) between a two-line contact (13) of the spring wire (10) with the associated spring mounting (5) .
3. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is configured as a pocket (8).
4. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is configured as a groove (7).
5. Camshaft adjuster (1) according to Claim 4, characterized in that the lubricant reservoir (6) which is configured as a groove (7) is arranged transversely or obliquely with respect to the spring wire (10).
6. Camshaft adjuster (1) according to Claim 4, characterized in that the lubricant reservoir (6) which is configured as a groove (7) is of circumferential configuration.
7. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is configured as a slot (11).
8. Camshaft adjuster (1) according to Claim 1, characterized in that the spring mounting (5) is configured as a journal (9).
9. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is produced by way of forming.
10. Camshaft adjuster (1) according to Claim 1, characterized in that the lubricant reservoir (6) is configured as a solid lubricating body (14).

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