EP3329104A1

EP3329104A1 - Camshaft adjuster

Info

Publication number: EP3329104A1
Application number: EP16753262.1A
Authority: EP
Inventors: Markus Heilig; Florian Hentsch; Dietmar Schulze
Original assignee: Hilite Germany GmbH
Current assignee: Hilite Germany GmbH
Priority date: 2015-07-30
Filing date: 2016-07-25
Publication date: 2018-06-06
Also published as: DE102015112442B3; US20180135475A1; CN107995936B; US10480360B2; CN107995936A; WO2017017058A1

Abstract

The invention relates to a camshaft adjuster (1) having a stator (2) driven by a crankshaft of an internal combustion engine, a rotor (4) which can be connected to a camshaft of the internal combustion engine in a rotationally fixed manner and which has a plurality of vanes (6) protruding radially outward from a rotor hub (7), wherein operating chambers arranged between the stator (2) and the rotor (4) are divided into pressure chambers (8, 9) by the vanes (6) and wherein the stator (2) and the rotor (4) are produced as sintered components. According to the invention, there are displacement recesses (14) on axially formed end faces (13, 15, 19, 20) of the stator (2) and/or of the rotor (4), into which material can flow during a deforming reworking process of the end faces.

Description

Phaser

The invention relates to a camshaft adjuster with a driven by a crankshaft of an internal combustion engine stator, a rotationally fixed with a

Camshaft of the internal combustion engine connectable rotor having a plurality of rotor blades radially outwardly projecting wings, wherein between the stator and the rotor arranged working chambers are divided by the wings in pressure chambers, and wherein the stator and the rotor are made as sintered components.

Camshaft adjusters are used in modern internal combustion engines to optimize the consumption and performance values and serve to change the opening and closing times of the gas exchange valves to the phase relation between crankshaft and camshaft in a defined angular range, between a maximum early and a maximum late position, variable to be able to shape. For this purpose, the camshaft adjuster is integrated into a drive train via which torques are transmitted from the crankshaft to the camshaft. The camshaft adjuster has one of the

Crankshaft driven stator and a non-rotatable with the camshaft

connected rotor. Between the rotor and the stator acted upon by a pressure medium working chambers are provided, which are divided by the rotor associated wings in oppositely acting pressure chambers. During the

Operation of the internal combustion engine, both pressure chambers are permanently filled with pressure medium, so that the rotor and the stator are relatively rigidly connected. The timing of the gas exchange valves are changed in that the pressure in one of the pressure chambers is increased, while the pressure in the other pressure chamber is lowered. The pressure medium must be supplied to the one pressure chamber and discharged from the other pressure chamber to a tank, which changes the angular position between the camshaft and the crankshaft. According to the prior art, in particular the components rotor and stator of the camshaft adjuster made of steel or aluminum alloys in

Sintered process produced. To ensure proper functioning of the

To ensure the camshaft adjuster follows the process steps

Pressing, greening and sintering a relatively elaborate and off

various processes existing finishing (calibration, grinding, fine turning, etc.) to those required in axially opposite surfaces

Ensure parallelism. These finishing processes are costly and involve quality risks that are exacerbated by intervening handling steps.

DE 10 2013 015 677 A1 offers as a solution to the disadvantages mentioned a method and a parts set with two Sinterfügeteilen and a

Radial deformation element on. This proposed, multi-part design of the stator or the rotor is considered disadvantageous due to the number of components and the complex joining process.

The invention is therefore based on the object to provide a camshaft adjuster, in which the required for the function of the camshaft adjuster precision can be achieved at a significantly reduced finishing costs while cost-effective production.

This object is achieved in that on axially formed end faces of the stator and / or the rotor displacement recesses are provided, in which material during a deforming

Post-processing of the end surfaces can flow. In other words, when depressing the blanks defined depressions in the form of

Recesses or grooves introduced, which are necessary for the post-sintering required by the deformation by the deformation

Provides displacement space, without the machined end faces in their

Carrying capacity such that the tolerable surface pressures are exceeded during operation. The end surfaces are preferably post-processed by means of height calibration. The height of the respective component and the parallelism of two opposing surfaces can in this way by a deliberate plastic deformation of the sintered material in a simple and cost-effective manner by means of a

Mold are produced.

By the displacement recesses on the axial end faces in

Are provided substantially evenly distributed, it is possible according to an advantageous development of the invention to avoid a deterioration of the load capacity of the end faces, so that a certain surface pressure during operation of the camshaft amplifier is not exceeded.

Preferably, the displacement recesses are formed three-dimensionally facet-shaped and each have a bottom surface and substantially

Trapezoidal side surfaces, so that each surrounding a circumferential web structure, the displacement recesses. The web structures preferably form a calibration structure.

According to an advantageous embodiment of the invention, the

Displacement recesses arranged on the end faces such that at least a portion of the web structures forms a continuous structure, which limits the end faces circumferentially. This encircling structure seals at

Concerning the respective end face on a corresponding surface of the

Camshaft adjuster, so that the leakage can be significantly reduced.

The calibration structure preferably has an area proportion adapted to the size of the sintering components. The area fraction is accordingly dependent on the size of the stator or the rotor. In general, the calibration structure forms a larger surface area for smaller components than for larger components. Even with smaller components, this can advantageously reduce the leakage and at the same time provide the necessary displacement space. In addition, a further deformation and thus an unwanted reduction in height of the components can be avoided during operation. The area ratios between the displacement recesses and the calibration structure contribute significantly to the degree of deformation achieved and thus the precision with regard to achieving a certain height dimension. As in the height calibration, the opposite surfaces with pressing force and

Counteracting force are applied, in addition to the intended plastic deformation also results in a significant proportion of elastic deformation, which leads to a springback of the deformed material components in relieving the component.

This elastic component must be kept low because it is considered to be a difficult parameter to control in the later tightening of the component in the

Camshaft adjuster applies and can have a negative impact there. Since, however, in such manufacturing processes, the elastic deformation component can not be entirely avoided during calibration, this is also compensated by a suitable method

Embodiment of the surface structure of the invention brought to a low and manageable level, which, for example, by a targeted

Shaping the transitions (flanks, radii, etc.) takes place.

In order to keep the elastic portion as small as possible, the angle of inclination of the trapezoidal side surfaces may be provided adapted to the surface portion of the calibration. Basically, it has been found that with a decreasing proportion of the recessed area (displacement recesses), the transitions between raised and recessed areas must be steeper, and vice versa.

Further advantages of the invention will become apparent from the other claims, the description and the drawings.

Show it:

1 shows a stator and a rotor of a known camshaft adjuster in perspective view,

2 a rotor of a camshaft adjuster according to the invention in FIG

perspective view, 3 a wing of the rotor of FIG. 2 partially cut and in perspective view,

4 is a plan view of the wing of FIG. 3,

5 a stator of a camshaft adjuster according to the invention in FIG

perspective view,

6 is an enlarged partial view of the stator of FIG. 5 and

Fig. 7 shows a stator of another embodiment of a camshaft adjuster according to the invention in a perspective view.

Fig. 1 shows a known camshaft adjuster 1, with which during the

Operation of an internal combustion engine, the angular position between crank and

Camshaft is changed. By turning the camshaft, not shown, the opening and closing times of the gas exchange valves are shifted so that the internal combustion engine brings its optimal performance at the respective speed. The Schwenkmotorversteller 1 allows a continuous adjustment of the camshaft relative to the crankshaft.

The camshaft adjuster 1 has a cylindrical stator 2, which is non-rotatably connected to a gear 3. In the exemplary embodiment, the gear 3 is a sprocket over which a chain, not shown, is guided. The gear 3 may also be a toothed belt, via which a drive belt as

Drive element is guided. About this drive element and the gear 3, the stator 2 is drivingly connected to the crankshaft in a known manner.

The stator 2 and the gear 3 are integrally formed with each other in this embodiment. Screws brace a stator cover, not shown, against the unit of stator 2 and gear 3. Are in an alternative

Embodiment stator 2 and gear 3 separate parts, so the stator 2 is clamped by means of screws between the gear 3 and a stator cover. The stator 2 is provided with radially inwardly projecting webs 5. Circumferentially between these webs 5 wings 6 of a rotor 4 are arranged. The rotor 4 has a rotor hub 7, which is rotatably connected to the camshaft. For this purpose, the rotor hub 7 is shrunk or pressed onto a camshaft end. In order to change the angular position between the camshaft and the crankshaft, the rotor 4 is rotated relative to the stator 2 against the force of a spiral spring. For this purpose, depending on the desired direction of rotation, the hydraulic fluid is pressurized in the pressure chambers 8 assigned to one direction of rotation, while the pressure chambers 9 assigned to the other direction of rotation are relieved to the tank. This the other direction of rotation associated pressure chambers 9 are shown in the drawing in the minimum state.

Thus, with the internal combustion engine switched off - i.e. at unloaded

Camshaft adjuster 1 - the rotor 4, the necessary for the engine start early

Exhaust camshaft position assumes the rotor 4 is rotated by the coil spring in an initial position. In this initial position, the rotor 4 is fixed relative to the stator 2 by means of a lock 10 against pivoting. This is housed in one of the wings 6. It is in pressure drop in the

Pressure chambers 8, 9 are not shown in detail a locking bolt by the spring force of a helical compression spring, not shown in a

Locking position moves, in which this engages in a locking opening of the stator cover, not shown. When starting the engine, the locking bolt is loaded by the hydraulic fluid against the spring force and pushed back, so that the rotor 4 is unlocked from the stator cover and the camshaft adjuster 1 can get into its control position.

The pressure chambers 8,9 can be supplied with hydraulic fluid via transverse bores 11, 12 or the hydraulic fluid can be drained from them.

For this purpose, for example, a hydraulic valve is arranged coaxially aligned within the camshaft end, which has at least one hydraulic piston.

The stator 2 and a rotor 4 of the camshaft adjuster 1 are generally made of steel or aluminum alloys and are produced in the sintering process. To ensure proper operation of the camshaft adjuster 1 follows In the process steps of pressing, green machining and sintering, this involves a relatively complex finish consisting of various processes

(Calibration, grinding, fine turning, etc.), to those in axially opposite

Ensure areas of required parallelism. These finishing processes are costly and involve quality risks, exacerbated by intervening handling steps.

To provide a camshaft adjuster 1, wherein the required for the function precision of the sintered components at significantly reduced

Endbearbeitungsaufwand can be achieved with simultaneous cost-effective production, the camshaft adjuster 1 according to the invention has on axially formed end faces of the stator 2 and / or the rotor 4th

Displacement recesses 14 on.

Fig. 2 shows a rotor 4 of a first embodiment of a

Camshaft adjuster 1 according to the invention. End surfaces 13, 15, which rests after assembly of the camshaft adjuster 1 on an inner surface of the stator 2, have displacement recesses 14, in which the material of the rotor 4 during a deforming Nachbearbeitungsverfahrens the end faces 13, 15 can flow. This post-processing is advantageously carried out by means of

Height calibration, in which the height of the respective component and the parallelism of two opposing surfaces by a deliberate plastic deformation of the sintered material in a simple and cost-effective manner by means of a

Mold can be produced.

When pressing the blanks (green compacts) defined depressions are thus introduced in the form of recesses or grooves, which necessary for the post-sintering required by the deformation by the deformation

Provides displacement space without affecting the so machined end faces 13, 15 in their carrying capacity such that the sustainable surface pressures are exceeded during operation.

By the displacement recesses 14 are provided on the axial end faces 13, 15 substantially uniformly distributed, it is possible to a Impairment of the carrying capacity of the end faces 13, 15 to avoid, so that a certain surface pressure during operation of the camshaft amplifier 1 is not exceeded.

As can be seen in particular from FIGS. 3 and 4, which show enlarged partial views of one of the wings 6, the displacement recesses 14 have a three-dimensionally facet-shaped design and each have a bottom surface 16 and in the

Substantially trapezoidal side surfaces 17, so that in each case a circumferential web structure 18 surrounds the displacement recesses 14. Go

adjacent displacement recesses 14 in the same web structure 18 via. The web structures 18 have essentially the same width distributed over the end faces 13, 15. The entirety of the web structures 18 forms a calibration structure which has an area proportion adapted to the size of the component. This can be a further deformation and thus an unwanted

Height reduction of components during operation can be avoided. It is the

Area proportion determined such that the necessary displacement space to

Is available and at the same time a desired seal can be ensured.

The area ratios between the displacement recesses and the calibration structure contribute significantly to the degree of deformation achieved and thus the precision with regard to achieving a certain height dimension. As in the height calibration, the opposite surfaces with pressing force and

Camshaft adjuster 1 is valid and can have a negative impact there.

However, since in such manufacturing processes the elastic deformation component can not be entirely avoided during calibration, it is also brought to a low and manageable level by a suitable embodiment of the surface structure according to the invention. This is through the above

described shaping of the displacement recesses 14 with the Side surfaces 17 achieved as a transition to the web structures 18. A further shaping can be done by radii etc.

In order to keep the elastic content as low as possible, is also the

Inclination angle of the trapezoidal side surfaces 17 adapted to the area ratio of the web structures 18. In principle, it has been found that for this purpose, as the proportion of recessed area (displacement recesses 14) decreases, the transitions between raised and recessed areas must be steeper, and vice versa.

Furthermore, it can be seen in particular from FIG. 2 that the displacement recesses 14 and the web structures 18 are arranged on the end faces 13, 15 such that a part of the web structures 18 form a continuous structure which circumscribes the end faces 13, 15. This circumferential structure allows for the application of the respective end face 13, 15 on inner surfaces of the stator 2, a secure seal of the end faces 13, 15, so that the leakage can be significantly reduced. This part of the web structures 18 can be made wider than the inner web structures 18 to improve the seal.

Fig. 5 and 6 show a stator 2 of the first embodiment, which is formed integrally according to FIG. 1 with a gear 3. As already described for the rotor 4, the stator 2 has at its end faces 19, 20 the displacement recesses 14 already described. It will be on top

Existing description referenced.

Fig. 7 shows a stator 2 of another embodiment, to which a toothed belt pulley or a pulley is rotatably fastened.

The described calibration structure with the displacement recesses 14 may be provided according to the invention on the rotor 4 or on the stator 2 or on both components, but finds in particular their advantageous application to the end faces 19, 20 of the stator 2. Here is in the design of the calibration to

take into account that in the assembled state as well as among all

Operating conditions the surface pressures that can be tolerated are not exceeded in order to be able to absorb the axially acting clamping forces safely and permanently without setting the clamping connection. The operating conditions in this case include in particular high temperatures at which the creep resistance of the materials adversely changes as well as axially and in particular radially acting mechanical forces, which can bring additional axially acting force components on the surface structured according to the invention.

Likewise, it is for the subsequent function of the inventively produced components 2, 4 of the camshaft adjuster 1 of great importance that in axial

opposite surfaces have tightest tolerances in terms of parallelism. The more important it is in the interpretation of the invention

Calibration structure on both end faces 13, 15 and 19, 20 to determine exactly which deformation components are plastic or elastic nature to be expected and thereby to take into account the force and the process influences in calibration with.

Further advantages of the calibration structure according to the invention will be apparent in the

Regard, as the height-calibrated end faces 13, 15 and 19, 20 with a

certain global topology, e.g. of the

Deformation of a rotor 4 accommodates in the tension on the camshaft end and thereby contribute to a further improvement in function at the same time reduced manufacturing costs.

LIST OF REFERENCE NUMBERS

Phaser

stator

gear

rotor

web

wing

rotor hub

pressure chamber

lock

cross hole

face

displacement recess

face

floor area

side surface

web structure

face

Claims

claims

1 . Camshaft adjuster (1) with

a driven by a crankshaft of an internal combustion engine stator (2), a rotatably connected to a camshaft of the internal combustion engine rotor (4) having a plurality of rotor hub (7) radially outwardly projecting wings (6), wherein between the stator (2) and the Rotor (4) arranged working chambers by the wings (6) in pressure chambers (8, 9) are divided, and wherein the stator (2) and the rotor (4) are made as sintered components,

characterized in that on axially formed end faces (13, 15, 19, 20) of the stator (2) and / or the rotor (4) displacement recesses (14) are provided, in which material during a deforming

Post-processing of the end surfaces can flow.

2. camshaft adjuster (1) according to claim 1, characterized in that the

End surfaces are reworked by means of height calibration.

3. camshaft adjuster (1) according to claim 2, characterized in that the displacement recesses (14) on the axial end faces (13, 15, 19, 20) are provided substantially uniformly distributed.

4. camshaft adjuster (1) according to claim 2 or 3, characterized in that the displacement recesses (14) are formed three-dimensionally facet-shaped and each have a bottom surface (1 6) and substantially trapezoidal side surfaces (17), so that in each case a circumferential web structure ( 18) surrounds the displacement recesses (14).

5. camshaft adjuster (1) according to claim 4, characterized in that the

Web structures (18) form a calibration structure.

6. camshaft adjuster (1) according to claim 5, characterized in that the

Displacement recesses (14) are arranged on the end faces (13, 15, 19, 20) such that at least a part of the web structures (18) a

form continuous structure which limits the end faces (13, 15, 19, 20) circumferentially.

7. camshaft adjuster (1) according to claim 5 or 6, characterized in that the calibration structure has an adapted to the size of the sintered portions surface portion.

8. camshaft adjuster (1) according to one of claims 5 to 7, characterized

characterized in that an inclination angle of the trapezoidal side surfaces (17) is provided adapted to the surface portion of the calibration structure.