DE102014200818A1 - Two-part stator with cold-welded lid - Google Patents

Abstract

The invention relates to a hydraulic camshaft adjuster, the vane type with a stator (1) and a rotor disposed concentrically within and which is connectable to a camshaft, wherein the stator (1) has a main body (3) with an at least partially hollow cylindrical shape and a Cover (4), wherein the lid (4) axially fixed and non-rotatably mounted on the main body (3), wherein between the main body (3) and the lid (4) at least partially a connection in the manner of a cold welding is formed. The invention also relates to a method for joining a cover (4) to a main body (3) of a stator, which is provided for forming a component of such a camshaft adjuster, wherein the cover (4) and the main body (3) in an axial and radial Dodge the material preventing negative mold to make a connection between the cover (4) and the main body (3) are subjected to high axial and radial forces.

Description

Field of the invention

The invention relates to a hydraulic phaser, for a motor vehicle, such as a car, a truck or other commercial vehicle, with a stator and a concentrically and internally disposed rotor, which is connectable to a camshaft, the stator having a main body / stator main body with a at least partially hollow cylindrical shape, for example in the manner of a Statortopfes or in the manner of a Statornapfes, and a example. Plate-like cover or arranged in a transverse plane end element, wherein the lid / the closure element is mounted axially fixed and rotationally fixed to the main body.

The invention thus resides in the field of vane-type adjusters, in particular in the field of vane adjusters.

From the prior art camshaft adjuster are already known, for example. From the US 6,457,447 B1 or the DE 2008 019 586 A1 , In the latter document, a camshaft adjusting device with a drive wheel and a driven part is disclosed, wherein the drive wheel and the driven part are rotatably arranged relative to each other and the rotational angle limiting between them at least one rotatably connected to the drive gear coupling element is provided, for rotationally fixed welding and / or caulking the coupling element and the drive wheel, the coupling element is radially supported on at least one contact portion of the drive wheel.

Such camshaft adjusters are usually used in control drives of internal combustion engines, in particular using chain or belt drives for both gasoline engines, as well as for diesel engines. Special camshaft adjusters, in which the stator is made of two or more separate parts and are positively and non-positively connected by special joining processes, are known. These already have advantages over one-piece Statortöpfen that must be made by machining, the functional surfaces must be laboriously processed.

The known prior art describes stator-lid combinations, which are normally carried out in one piece, or are connected by caulking or interference fits. In one-piece designs, all functional surfaces, such as radial, thrust bearing and sealing surfaces must be machined, resulting in high production costs.

Geometriebedingt is then used as a machining process, a milling process, which brings with it further functional disadvantages. The result of milling through a bevelled or rounded cutter outlet a circumferential positive edge fracture, which can also be referred to as Materialaufwurf / material accumulation, namely at the transition of a thrust bearing surface of the lid to the radial Statorwandung. A diametrically opposite chamfer must then be held on the rotor in order to avoid jamming in the axial bearing. This in turn results in increased leakage through the circumferential gap between the rotor and the stator. In addition, when using sealing strips, so strips, which are set to the fluid-tight delimitation of the vane on the outside of the rotor and the inside of the stator on the rotor extending in the axial direction, especially one-sided beveled variants are used, which at this point the edge break on Statortopf also hold. In other words, they must be excluded in the area of material accumulation / material disposal, i. have a recess. This makes a directed assembly necessary, which in turn requires an increased effort.

It is the object of the present invention to avoid the disadvantages known from the prior art and in particular to provide a stator-lid combination which is assembled from individual parts, but is particularly dense and inexpensive. In particular, a particularly structurally stable stator-lid combination is to be made available.

Disclosure of the invention

This object is achieved in a generic device according to the invention in that at least in sections, a connection is formed in the manner of a cold welding between the main body and the lid.

A cold welding is understood to mean a connection at the atomic level under the action of high pressure and / or a (high) relative speed.

Advantageous embodiments are claimed in the subclaims and are explained in more detail below.

Thus, it is of advantage if the cold welding which is expediently provided in a sintering press process is present on an end face of the main body and / or an (inner) circumferential face of the main body. A large interface can then be provided.

It is also advantageous if the cold welding has force-fitting, positive-locking and / or cohesively acting connecting sections, in particular one or more microforming sections. In this case, it is particularly expedient for such a form fit, which acts especially at the micro level, for example by means of specially structured surfaces. Under the action of high forces then forms the cold welding. A gearing effect of surface structures is subsumed here. For example, a steam treatment which causes a microform closure by "rusting" at the atomic level also occurs here.

A further advantageous embodiment is also characterized in that a microstructure, such as in the manner of a corrugation, groove and / or (micro) toothing is provided at portions of the contacting surfaces of the main body and the preferably ring-like lid. The cohesion of the items is thereby improved.

It is also advantageous if the main body and / or the cover is constructed of preferably metallic sintered material / are.

If the main body and the lid attached to it are oxidized, rusted, rusted or burnished using, for example, steam treatment, the cohesion of the individual components can be further improved.

It is useful if axially extending projections of the main body or the lid are positively inserted into recesses of the lid or the main body. The transferable forces can then get even bigger.

An advantageous embodiment is also characterized in that adhesive agent / adhesive, such as adhesive or wax, is present in the region of the cold welding.

So that the connection is particularly durable, it is advantageous if the lid is sintered with the main body.

The invention also relates to a method for joining a lid to a main body of a stator, which is provided for forming a component of a camshaft adjuster of the type according to the invention, particularly preferably for producing a connection in the manner of a cold welding between the lid and the main body, that lid and that main body in a negative mold, which prevents axial and radial deflection of the material, be subjected to high axial and radial forces.

It could also be said that the invention relates to the division of the stator into several parts, wherein the separation can take place in the radial or in the axial direction. The case, also described in detail later, concretely describes a stator-lid unit which is in two parts in the first production cut, namely comprising a (stator) main body and a lid, which can subsequently be referred to as a "calibration process" by a joining process , is connected.

A "calibration process" is understood to mean a process which improves the dimensional stability of the workpiece by overpressing using very high forces. The workpiece is placed in a negative mold and subjected to very high axial and / or radial forces, resulting in an investment in the negative mold. By this plastic deformation, the workpiece is subsequently compacted and increases the dimensional accuracy.

The connection by "calibration" leads to a non-positive and positive connection, which can transmit high operating loads. For this reason, a toothing, via which the timing chain is mounted positively, and a locking function integrated into this component combination.

Another advantage of the stator can be utilized when there is a circumferential, radial seal at the outer diameter between the cover and the stator which reduces the external radially outward leakage. In the absence of such a form-fitting design, a gap of several microns, about 20 microns may occur, resulting in leakage. A circumferential positive seal is achieved by "overpressing", ie a penetration of the individual parts in the micro range, similar to a press fit but with higher joining forces during the "calibration". For this purpose, a geometric overlap between the stator and the lid is realized, which is implemented radially on the outer diameter or by individual elements in the region of the stator segments.

By assembling the Statortopfes of two separate components, the reworking by milling can be omitted, since the functional surfaces can also be made sufficiently accurate by "calibrate". In addition, there is no circumferential "positive edge break", so no accumulation of material, this positive edge fracture would bring the aforementioned disadvantages with it. Symmetrical sealing strips and a "sharp-edged" rotor surface can be used, which in turn has a positive effect on the hydraulic leakage, i. she stops.

When connecting the two components as well as the axial bearing width is produced very accurately in the stator by the axial compression. This machining post-processing (height grinding) can thus be omitted.

In order to further increase the connection strength of the individual parts, it is conceivable to provide a microstructure at the joining surfaces. Due to the axial compression namely material of the two joining partners flows into each other and there is a micro-toothing. Furthermore, by a heat treatment, e.g. using a steam treatment, a "rusting" of the individual parts are generated with each other, which also increases the connection stiffness. In addition, a connection can be made via an additional operation such as sintered soldering.

These types of component connection can be used constructively to provide higher degrees of freedom, such as, for example, to achieve in a manufactured as a single piece Static pot. Undercuts can be made between the stator and the lid for cropping e.g. the link plates or other components are created, which could otherwise be produced only by elaborate machining rework. Thus, the lid may extend radially far beyond the tooth-free outer peripheral surface of the stator. A radial step between the lid and the stator main body is then the result. As a result, local geometric elements can be introduced, which can serve for positioning as a tool engagement during assembly and thereby do not reduce the strength over the entire width.

It can be introduced in the field of cold welding and an adhesive agent. This creates an adhesive connection. A general description of "Adhäsionskräfte" which, for example, by the use of additives such as adhesive, wax or the like increases, in addition, even the sealing function is improved. Such is, for example, in the WO 2010/128976 A1 disclosed. The relevant details should be considered as clarified here.

Geometric elements in the axial direction are also provided on the individual parts of the main body and the cover, such as projections which produce a positive connection in the connected state and thus reduce the operating load in the circumferential direction for receiving torque.

If space constrained, a cranked gearing, i. a toothing that projects radially or axially beyond the stator cover may be desired, this can be implemented without mechanical reworking, such as a turning process. For this purpose, the lid is attached in the undercut of the toothing on the stator by positive locking or frictional connection (press fit).

When designing a frictional connection by a high-force calibration process, the structural rigidity of the assembly can be exploited to transmit higher operating loads, or at the same operating loads, the wall thickness and thus the entire mass of the camshaft adjuster can be reduced.

As structurally significant points, it should be noted that two separately produced individual parts, preferably of sintered material, can be used, which can then be connected to one another in a form-locking and force-locking manner by a calibration process.

There are the geometry elements on the stator main body and the lid held, which engage axially and radially during joining into one another and result in a non-positive connection by the action of high pressing forces. These geometric elements are used to design the connection (fit during joining), to absorb forces and moments during operation and to seal against leakage, such as in the design of a circumferential groove on the stator main body or cover. In the groove can then grab a gegengleiche circumferential collar design of the other component.

For sealing against leakage at the outer diameter, different geometries between the stator and the cover, such as circular grooves, rectangular grooves, labyrinth forms or the like may be provided.

The design of a sharp-edged connection or of a negative edge break, that is to say the lack of a material accumulation, running around an axial surface at the transition between the stator main body or sealing cover, leads to a minimization of the circulating leakage gap.

It is a design possible in which a depression or bore can be introduced on the lid, via which the mechanical locking can be realized.

The design of the contact surfaces before the trains by means of a microstructure is advantageous, in which case a toothing effect can be realized during the joining process, which increases the connection strength. As a side effect can be implemented by this microstructure a much more accurate bearing width / axial width, so that a subsequent height grinding can be omitted.

Increasing the bond strength through an aftertreatment process, such as a steam treatment was highlighted. The connection of the individual parts via rust formation, toothing via a microstructure or sintered soldering has already been mentioned.

A general abandonment of a machining rework of the functional surfaces is the result.

Even cranked teeth up to over the top level without machining reworking can be realized.

Higher transferable operating loads can then be dealt with. The effort of production is reduced. Cost-intensive (fusion) welded joints can be dispensed with. The inventive method can also be used in multi-part rotors.

The invention will be explained in more detail with the aid of a drawing, in which different embodiments are shown. Show it.

1 a top view of a stator main body, which is combined with a cover to a composite stator and is part of a camshaft adjuster according to the invention,

2 a cross section along the line II 1 through the composite stator,

3 a perspective view of only the stator main body,

4 a perspective view (from the other side) of the lid of the stator,

5 to 8th a second embodiment according to the representations of 1 to 4 .

9 to 12 comparable to the representation of the 1 to 4 .

13 an enlargement of the range XIII 9 .

14 a variant of the embodiment as in 13 shown,

15 . 16 and 17 a further embodiment of a stator to be installed in a camshaft adjuster according to the invention, constructed of a stator main body and a lid with domes, and a frictional connection on the outer diameter of the lid, wherein 16 a longitudinal section along the line XVI 17 reflects and the 15 and 17 represent the front or rear view,

18 a perspective view of only one stator main body of another embodiment of the invention, and

19 a perspective view of only the lid, which comes into contact with the stator main body 18 is provided.

The figures are merely schematic in nature and are only for the understanding of the invention. Elements of the individual embodiments can be exchanged / exchanged with each other.

1 shows a stator according to the invention 1 , which can be used in a first embodiment of a hydraulic camshaft adjuster. A rotor with which it interacts is not shown. For this is a gearing 2 on the outside of the stator 1 to recognize. The gearing 2 is prepared to come into contact with a timing chain, not shown. The stator 1 is from a main body 3 and a lid 4 built up. The main body 3 and the lid 4 are positively connected via a tongue and groove and then joined non-positively by a "calibration" with each other. This shows the lid 4 axially protruding projections 5 on, in the opposite recesses / recesses 6 at the main body 3 intervention.

The 2 to 4 reflect the interaction of the individual components well. The individual components are concentric to a rotation axis 7 educated.

In the 5 to 8th is a variant of the embodiment of the 1 to 4 to recognize, with a good sealing function on the outer diameter by a ring seal 8th is realized. Circumferential noses are on the lid 4 present with a groove on the stator main body 3 or vice versa attached. The grooves in the area of the stator segments also serve to absorb torques. The groove is denoted by the reference numeral 9 marked, in which a covenant 10 on the lid 4 can intervene. In addition, there is a positive connection in the circumferential direction.

In the 9 to 14 a further variant is shown, wherein a statortopfartiger main body 3 with calibrated lid 4 over dome 11 , which by form and adhesion with the holes 12 in the main body 3 be joined together. It can be a thread 13 in the lid 4 be provided to reinforce the component connection. As in 13 shown, the thread may be 13 also extend over both components to reinforce the connection.

A negative edge break, like an undercut, can occur between the lid 4 and the main body 3 to release a radial bearing, or a radial storage location 14 (please refer 11 ), be used.

A stubborn main body 3 with cranked teeth on the calibrated lid 4 is in the representations of 15 to 17 shown. In the corresponding embodiment, the lid 4 via a press fit (traction) between the teeth 2 and the lid outer diameter 15 without additional connection via a screw connection with the main body 3 combined. A strong connection is made over the dome 11 and a frictional connection on the outer diameter of the lid 4 reached.

In the 18 and 19 is another variant of a main body design and lid design with a microstructure 16 shown. This serves to improve the connection strength and to be able to calibrate the bearing height more accurately. The microstructure 16 is at the contact surface between the stator main body 3 and the lid 4 present and leads to an increase in the connection strength in the micro range. This is similar to a gearing effect. A steam treatment at about 200 to about 250 ° C to achieve "Edelrost" can be combined in the individual embodiments.

LIST OF REFERENCE NUMBERS

1

 stator

2

 gearing

3

 main body

4

 cover

5

 head Start

6

 Recess / recess

7

 axis of rotation

8th

 ring seal

9

 groove

10

 Federation

11

 cathedral

12

 drilling

13

 thread

14

 wheel

15

 Cover external diameter

16

 microstructure

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6457447 B1 [0003]
• DE 2008019586 A1 [0003]
• WO 2010/128976 A1 [0028]

Claims (10)

Hydraulic camshaft adjuster with a stator ( 1 ) and a rotor arranged concentrically therewith and which can be connected to a camshaft, wherein the stator ( 1 ) a main body ( 3 ) with an at least partially hollow cylindrical shape and a lid ( 4 ), wherein the lid ( 4 ) axially fixed and rotationally fixed on the main body ( 3 ), characterized in that between the main body ( 3 ) and the lid ( 4 ) is at least partially formed a connection in the manner of a cold welding. Camshaft adjuster according to claim 1, characterized in that the cold welding on an end face of the main body ( 3 ) and / or a peripheral surface of the main body ( 3 ) is available. Camshaft adjuster according to claim 1 or 2, characterized in that the cold welding force, positively and / or cohesively acting connecting portions, in particular one or more microforming sections. Camshaft adjuster according to one of claims 1 to 3, characterized in that at portions of the contacting surfaces of the main body ( 3 ) and the lid ( 4 ) a microstructure ( 16 ) is provided. Camshaft adjuster according to one of claims 1 to 4, characterized in that the main body ( 3 ) and / or the lid ( 4 ) is constructed of sintered material / are. Camshaft adjuster according to one of claims 1 to 5, characterized in that the main body ( 3 ) and the lid attached to it ( 4 ), such as using a steam treatment, anoxidized, rusted, rusted or burnished. Camshaft adjuster according to one of claims 1 to 6, characterized in that extending in the axial direction projections ( 5 ) of the main body ( 3 ) or the lid ( 4 ) in recesses ( 6 ) of the lid ( 4 ) or the main body ( 3 ) are used. Camshaft adjuster according to one of claims 1 to 7, characterized in that in the region of the cold welding an adhesive agent, such as adhesive or wax, is present. Camshaft adjuster according to one of claims 1 to 8, characterized in that the cover ( 4 ) with the main body ( 3 ) is sintered. Method for joining a cover ( 4 ) on a main body ( 3 ) of a stator ( 1 ), which is provided for forming a component of a camshaft adjuster according to one of claims 1 to 9, characterized in that the cover ( 4 ) and the main body ( 3 ) in an axial and radial deflection of the material to prevent negative mold for making a connection between the lid ( 4 ) and the main body ( 3 ) are subjected to high axial and radial forces.

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