CN114562347A

CN114562347A - Stator cover

Info

Publication number: CN114562347A
Application number: CN202111417103.4A
Authority: CN
Inventors: K·狄金格; W·西斯尔
Original assignee: Miba Sinter Austria GmbH
Current assignee: Miba Sinter Austria GmbH
Priority date: 2020-11-27
Filing date: 2021-11-26
Publication date: 2022-05-31
Also published as: AT524466A1; DE102021131041A1; AT524466B1

Abstract

The invention relates to a stator cover (8) for a stator (6) of a camshaft adjuster (2), comprising a cover body (23) which has a first end face (24) which forms an abutment face (26) with which the cover body (23) can be brought into abutment against the stator (6), wherein at least 40% of the abutment face (26) is formed so as to be raised relative to the remainder of the first end face (24).

Description

Stator cover

Technical Field

The invention relates to a stator cover for a stator of a camshaft adjuster, comprising a cover body which has a first end face, which forms an abutment face with which the cover body can be brought into abutment against the stator.

The invention further relates to a camshaft adjuster, in particular a hydraulic camshaft adjuster, comprising a stator and a rotor, wherein the rotor is arranged at least partially, in particular integrally, within the stator, and a stator cover connected to the stator.

The invention further relates to a method for producing a camshaft adjuster, in particular a hydraulic camshaft adjuster, comprising: a stator having a stator base body manufactured to have outer end face teeth portions, a radially inner peripheral surface, and strips projecting radially inward from the radially inner peripheral surface and spaced from each other in a circumferential direction of the stator base body; a rotor rotatable relative to the stator, the rotor having a rotor base body at least partially surrounded by the stator and fabricated to have a wing portion protruding radially outward from a radially outer circumferential surface, thereby constituting a plurality of hydraulic working spaces between the stator and the rotor, the plurality of hydraulic working spaces being divided into a first working chamber and a second working chamber by the wing portion of the rotor, respectively; wherein the stator and the rotor are manufactured to have a first plane on a first end face; wherein the rotor and/or stator is manufactured according to a powder metallurgy method.

Background

Camshaft adjusters are known for adapting the valve opening times in order to thus achieve a high efficiency of the internal combustion engine. The camshaft adjuster is known from the prior art in various embodiments. The hydraulic camshaft adjuster comprises a stator in which a rotor is arranged. The rotor is connected with the camshaft in a torsion-proof manner. The stator connected to the crankshaft has radially inwardly projecting strips which form stop surfaces for the wing sections of the rotor. It is therefore possible to rotate the rotor relative to the stator only within a predetermined angular range.

In this respect, it is also known to produce at least some camshaft adjusters powder metallurgically from a sintered material. DE 102013226445 a1, for example, describes a camshaft adjuster for an internal combustion engine according to the vane type, which comprises a stator and a rotor, which is rotatable relative to the stator and is composed of a plurality of interconnected rotor parts, wherein the rotor can be connected to a camshaft of the internal combustion engine in a rotationally fixed manner, and the first rotor part is designed such that the camshaft bears against the first rotor part in the operating state, wherein the first rotor part is produced by means of a sintering process, and at least one first bearing surface of the first rotor part, which supports the camshaft, is adjusted geometrically by means of a non-cutting machining process.

DE 102013015677 a1 describes a method for producing sintered parts with highly precise radial accuracy, wherein the sintered parts are produced from at least one first sintered joint and a second sintered joint, and the method comprises at least the following steps: joining the first sintered joint with the second sintered joint; leading to highly accurate radial accuracy; there is a deformation of at least one radial deformation element, which is preferably positioned adjacent to the contact engagement zone, wherein the deformation of the radial deformation element is at least brought about by means of a calibration tool and is at least substantially realized as a plastic deformation of the radial deformation element.

As can be seen from the prior art, the precision of the components plays a correspondingly large role. The production of such camshaft adjusters is associated with considerable expenditure.

Disclosure of Invention

The aim of the invention is to simplify the production of a (hydraulic) camshaft adjuster.

The object of the invention is achieved by the stator cover mentioned at the beginning, wherein it is provided that at least 40% of the contact surface is formed so as to be raised with respect to the rest of the end face.

The object of the invention is also achieved by means of the initially mentioned camshaft adjuster, which has a stator cover according to the invention.

The object of the invention is also achieved by means of the method described at the outset, wherein provision is made for the first and second planes of the stator and rotor to be ground or finished, in particular ground together; and thereafter the stator and the rotor are covered with a stator cover according to the invention.

In this case, it is advantageous that the axial play between the rotor and the stator can be adjusted more easily by means of the raised contact surfaces, i.e. by means of the step of the end faces. In particular, when grinding the rotor and the stator to the same height tolerance, the oil clearance can be reduced if necessary by means of the embodiment of the stator cover. The flatness tolerance on the stator cover can be increased if the oil gap remains the same, so that it is therefore no longer necessary to machine the bearing surfaces of the stator cover to reduce the tolerance. Thus, the production steps in the production of the camshaft adjuster can be omitted. However, if this machining step is to be carried out, the height tolerances of the rotor and stator can be adapted in turn, so that machining steps, for example grinding, can be saved on these components if necessary.

According to one embodiment of the invention, it can be provided that the raised region of the contact surface is designed as a plane. Tolerance adaptation can thereby be further simplified.

Preferably, according to a further embodiment variant of the invention, it can be provided that the contact surface of the elevation projects beyond the rest of the end face by a height selected from the range of 2 μm to 100 μm. Below 2 μm the effect of the raised end face is relatively small. A step of more than 100 μm may be advantageous in particular, but this upper limit has proven to be advantageous when the camshaft adjuster is produced in series, since the oil gap can thereby be kept small.

According to a further embodiment of the invention, it can be provided that only one raised contact surface is formed, which extends over 360 ° of the cover. The force distribution can thus be made uniform during the assembly of the camshaft adjuster, as a result of which the stator cover can be arranged more precisely on the stator. Subsequently, it is therefore also possible to reduce the tolerances in the system "camshaft adjuster".

According to a further embodiment variant, it can be provided that the cover is made of a sintered material. The step can thus be produced simply, in particular in a given region with a small height.

According to a further embodiment of the invention, it can be provided that the contact surface is hardened. This also advantageously affects the clampability of the stator cover on the stator, whereby tolerances can likewise be reduced. In this case, the hardening itself can take place within the scope of the production steps of the stator cover, which are always carried out, i.e. for example, sintering of the stator cover, so that no additional steps are required for this purpose.

As already mentioned, according to one embodiment variant it is preferably provided that the contact surface is not ground. This in turn allows the contact surface to be adapted to the corresponding clamping surface of the stator to a certain extent in such a way that the "unevenness" is pressed during clamping.

In accordance with an embodiment of the camshaft adjuster, it can be provided that the contact surface of the stator cover is provided only in the region of the end face that directly contacts the stator. Overlapping with the rotor can therefore be avoided more simply, as a result of which the assembly of the camshaft adjuster can be simplified.

Drawings

For a better understanding of the present invention, it is illustrated in more detail according to the following figures. In each case, the following are shown in simplified schematic form:

FIG. 1 shows a portion of an internal combustion engine;

FIG. 2 shows a stator and a rotor of a camshaft adjuster in an oblique view;

fig. 3 shows an embodiment variant of the stator cover in an oblique view of the first end face;

fig. 4 shows the stator cover according to fig. 3 in an oblique view of the second end face;

fig. 5 shows a cross-sectional view of the stator cover according to fig. 3;

fig. 6 shows a detail of the stator cover according to fig. 3 in a sectional view.

Detailed Description

It should be noted at the outset that identical components in the different described embodiments are provided with the same reference numerals or the same component names, wherein the disclosure contained in the entire description can be transferred to identical components having the same reference numerals or the same component names in a meaningful manner. Furthermore, the position indications selected in the description, for example upper, lower, lateral, etc., relate to the figures described and illustrated directly, and in the event of a change in position, these position indications can be transferred to the new position in the sense of meaning.

Fig. 1 shows a detail of an internal combustion engine 1. The hydraulic camshaft adjuster 2 and the drive wheel 3 can be seen. The camshaft adjuster 2 has a spur toothing 4 on its outer circumference. Likewise, the drive wheel 3 has a spur toothing 5 on its outer circumference. The two face toothing systems 4, 5 mesh with one another.

The spur toothing 4 of the camshaft adjuster 2 can also be designed for engaging a timing chain (steuerkey) or a drive belt (not shown).

In principle, the design of the hydraulic camshaft adjuster 2 is known from the prior art, so that further explanations thereof are not necessary.

As can be seen from fig. 2, the camshaft adjuster 2 has a stator 6 and a rotor 7. Furthermore, the camshaft adjuster 2 has at least one stator cover 8, which is shown in fig. 3 to 6. According to embodiments, the camshaft adjuster 2 may have one or two stator covers 8. In the case of only one, the second "cover" is formed in one piece with the stator 6, so that the stator can thus be formed in an almost pot-shaped manner for receiving the rotor 6.

The stator 6 has an annular stator base body 9, which, as described above, has external teeth in the form of the end-face teeth 4 on its outer circumference. The strips 11 are formed on a radially inner circumferential surface 10 of the stator base body 9 and project radially inward via said circumferential surface. In the specific case, the stator 6 has four slats 11. However, this number of slats 11 should not be understood in a limiting manner. There may also be more or fewer slats 11. The bar 11 can be provided with recesses 12 or through-openings as required, in order to thus impart less weight to the stator 6. However, the recess 12 can also be used, depending on the embodiment of the stator cover 8, for receiving screws or the usual fastening means with which the stator cover 8 is fastened (fixed) to the stator 6. The individual strips 11 are arranged on the stator base body 9 at a distance from one another in the circumferential direction 13.

Within the stator 6, the stator cover 8 (fig. 1) is omitted as described above, the rotor 7 is arranged completely or at least partially. The rotor 7 has a (annular) rotor base body 14. On the outer circumferential surface 15 of the rotor base body 14, wings 16 are formed or arranged, which extend radially outward from the circumferential surface 15. In the assembled state of the camshaft adjuster 2, the limbs 16 are arranged between the individual strips 11 of the stator 6. The side surfaces 17 of the slats 11 form stop surfaces for the wings 16 of the rotor 7, as can be seen from fig. 2.

The number of wings 16 of the rotor 7 depends on the number of slats 11 of the stator 6, so that in the specific case there are thus four wings 16.

Each slat 11 defines a hydraulic working space 18. Each working space 18 is bounded in the circumferential direction 13 by two slats 11. The wings 16 of the rotor 7 divide the working space 18 into a first working chamber 19 and a second working chamber 20, respectively, by means of the wings 16 arranged between the slats 11. As is known per se, the relative position of the rotor 7 with respect to the stator 6 can be changed by means of a fluid which can be introduced into the working

chambers

19, 20, so that reference should be made to the relevant prior art for this purpose.

It should be noted that a hydraulic embodiment of the camshaft adjuster 2 is preferred. The camshaft adjuster 2 may however also be formed in addition.

The rotor 7 is thus arranged within the stator 6 so as to be rotationally movable in the circumferential direction 13 relative to the stator 6, wherein the path of rotation is limited by the slats 11. The camshaft adjuster 2 therefore operates according to the rotary electric machine principle. The camshaft adjuster 2 is driven by a chain or belt drive or a drive wheel 3 to adjust gas exchange valves to an earlier or later point in time relative to the opening and closing times of a drive shaft, for example a crankshaft, in order to influence the combustion process in the internal combustion engine. In this case, the camshaft is adjusted either in the "early" direction or in the "late" direction by filling the opposing working

chambers

19, 20 formed between the rotor 7 and the stator 6 of the camshaft adjuster 2 with a suitable hydraulic medium.

A control valve (also referred to as a central valve) can be arranged at least partially within a receptacle 22 (recess) of the rotor 7, which receptacle extends in the axial direction 21 or in particular extends through the rotor 7, i.e. is at least partially surrounded by the rotor 7.

Fig. 3 to 6 now show an embodiment variant of the stator cover 8 in more detail.

The stator cover 8 has a cover body 23. The cover 23 (which can be of at least approximately cylindrical design) has a first end face 24 and a second end face 25, which is formed on the cover 23 opposite the first end face 24 in the axial direction 21. The first end face 24 is the face with which the cover 23 rests, in particular rests directly on the stator 6. Correspondingly, the second end face 25 is generally the face which can be seen on the camshaft adjuster 2.

The first end face 24 comprises or forms an abutment face 26 with which the stator cover 8 abuts against the stator 6. The abutment surface 26 is configured to at least partially bulge with respect to the remaining portion of the abutment surface 26 or the first end surface 24. At least 40% of the contact surface 26 is designed to be raised. In particular, between 40%, preferably 50%, particularly preferably 60% and 100% of the contact surface 26 is designed to be raised. It can therefore also be provided that the entire contact surface 26 is formed in a raised manner with respect to the first end face 24, i.e. protrudes beyond the first end face 24. The contact surface 26 can have a total surface area of 20%, preferably 40%, particularly preferably 50% or 60% to 80%, of the entire first end surface 24. The first end face 24 is viewed in the axial direction 23. The entire first end face 24 is therefore understood to be the sum of the contact face 26 and the rest of the first end face 23.

In principle, the contact surface 26 can have any suitable shape. The contact surface can be at least partially arched, for example. According to a preferred embodiment variant, one or more contact surfaces 26 (more than one contact surface 26 can also be provided on the first end face 24) are designed as flat surfaces.

In general, the contact surface 26 can be a machined surface, for example a ground surface. However, according to an embodiment variant of the stator cover 8, it can be provided that the contact surface 26 is configured untreated, in particular unground. If the stator cover 8 is produced from a sintered material according to another embodiment variant by a sintering method, the contact surface 26 can be rough-sintered, for example.

However, the stator cover 8 can also be manufactured separately, for example by press-casting a material or the like.

The contact surface can have a surface roughness of between Rz 2 μm and Rz 28 μm to DIN EN ISO 4287.

It is furthermore advantageous to use a sintering powder having a particle size distribution according to DIN ISO4497 between 5 μm and 250 μm, preferably between 30 μm and 150 μm.

Any suitable metal or any suitable metal alloy, for example steel, aluminum, etc., can be used as the material for the stator cover 8.

As can be seen in particular from fig. 6, the height 27 of the contact surface 26 above the first end surface 24 is preferably relatively small. According to one embodiment of the stator cover 8, the height 27 is between 2 μm and 100 μm, in particular between 10 μm and 50 μm.

As mentioned above, a plurality of contact surfaces 26, which can also be referred to as segmented contact surfaces 26, can be provided or formed on the first end surface 24. The contact surfaces 26 can be arranged next to one another in the circumferential direction 13 and/or in the radial direction. These contact surfaces can all have the same dimensions or at least partially have different dimensions.

However, according to a preferred embodiment of the stator cover 8, it can be provided that only a single raised contact surface 26 is formed, which extends over 360 °, i.e. completely, of the cover body 23. This embodiment variant is shown in fig. 3. The contact surface 26 is formed annularly. Projecting from the ring are radially inwardly projecting tabs 28. The extent and dimensions of the projections 28 may be the same here as the extent and dimensions of the strips 11 of the stator 6 (viewed in the axial direction 21, respectively). However, the projection 28 may also have a different size and/or shape than this.

The contact surface 26 can be formed or arranged so as to start at the outer circumference of the stator cover 8, for example, in the form of a ring and extend radially inward, as can be seen in fig. 3. The radial width 29 of the ring of the contact surface 26 can thereby follow the radial width, in particular the same size, of the annular stator base body 9 (which reaches as far as the starting point of the bar 11). However, the ring of the contact surface 26 can also be designed thinner or wider than this. Furthermore, the contact surface 26 can also be formed or arranged at a distance from the outer circumference of the stator cover 8.

As can be seen from fig. 4, the second end face 25, apart from the holes 30, in particular countersunk holes, can be designed to be completely planar, i.e. without further elevations or depressions. The holes 30 are used to receive connecting means, in particular screws, with which the stator cover 8 is fastened to the stator. Preferably, a countersunk screw is used, so that the screw (substantially) does not protrude beyond the second end face 25 of the cover 23 due to the countersunk hole. Preferably, the holes 30 are positioned such that they also extend through the projections 28 of the abutment surface 26. The number of connecting means may correspond to the number of slats 11 of the stator 6.

As already mentioned, the at least one contact surface 26 is preferably a raw surface, in particular a non-machined surface. However, the at least one contact surface 26 may be a hardened surface. Hardening can be carried out, for example, by means of a laser beam, by sinter hardening, induction hardening, quench hardening, case hardening, etc. Since these methods are known per se, they need not be discussed in more detail.

The contact surface 26 can be larger or smaller than the end face of the stator 6, against which the contact surface 26 contacts. However, according to a preferred embodiment of the camshaft adjuster 2, the contact surface 26 of the camshaft adjuster 2 is formed only in the region of the first end surface 24 that directly contacts the stator 6. The contact surface 26 can therefore be no larger than the end surface of the stator 6, but can be of the same size.

The rotor 7 is preferably manufactured by means of a powder metallurgy method. The method comprises the following method steps:

-providing a first powder for manufacturing the rotor 7 in a mould cavity of a mould;

-pressing the first powder in a mould into a rotor green piece;

-green working of the rotor green parts, if necessary;

-sintering the rotor green part;

-reprocessing the rotor material for removal.

However, the rotor 7 may also be manufactured according to other methods.

The stator 6 is furthermore preferably a one-piece component, in particular a sintered component (i.e. produced from a sintered material according to a powder metallurgy method), so that the end face toothing 4 and the webs 11 together with the base body 9 thus form a single integral component, in particular a sintered part. The method comprises the following method steps:

-providing a second powder for manufacturing the stator 6 in the mould cavity of the mould;

-pressing the second powder in a mould into a stator green part;

green machining of the stator green part, if necessary;

-sintering the stator green part;

-material-free reworking of the stator 6;

hardening the face teeth 4 of the stator 6, if necessary.

However, the stator 6 can also be manufactured according to other methods.

The green machining or material-removing machining of the stator 6 and/or the rotor 7 can be carried out, for example, by grinding, polishing, honing (Hohnen), etc.

The hardening of the face tooth 4 can be performed by, for example, induction hardening, quench hardening, surface hardening, or the like.

The sintering of the stator 6 and/or the rotor 7 can be carried out in one or more stages. Furthermore, the sintering can be carried out at a temperature between 700 ℃ and 1300 ℃ in a time interval of, for example, 10 minutes to 120 minutes.

Since the powder metallurgical production of sintered parts is known per se from the prior art, reference should be made to the relevant prior art in order to avoid repetitions.

The stator 6 has a first plane 31, which is formed on or by a first end face 32 of the stator 6. Likewise, the rotor 7 has a first flat surface 33, which is formed on a first end face 34 of the rotor 7. The first plane 31 of the stator 6 is arranged flush with the first plane 33 of the rotor 7 within tolerance, as can be seen in particular from fig. 2 and 4.

The first plane 33 of the stator 6 is formed on the bar 11 and, in the embodiment shown, on an annular bar 35 of the stator base body 9, wherein, in the embodiment shown, the first plane 31 of the stator 6 extends at least over the entire end faces of the bar 11 and the annular bar 35. However, if the strip 11 has a step (abstufang), for example, the first plane 31 of the stator 6 may also extend over only a part of this plane.

A first plane 33 of the rotor 7 is formed on the limb 16 and, in the embodiment shown, on an end face 34 of a hollow cylinder 36 of the rotor base body 14 (or of the rotor base body 14), wherein, in the embodiment shown, this first plane 33 of the rotor 7 extends at least over the entire end face of the limb 16 and the hollow cylinder 36. However, the first flat surface 33 of the rotor 7 may also extend over only a portion of this surface, for example if the wings 16 or the hollow cylinder 36 have a step.

The first flat surface 31 of the stator 6 bears sealingly (within tolerance) against the stator cover 8 of the camshaft adjuster 2.

Provision is preferably made for the first

flat surfaces

31, 33 of the stator 6 and of the rotor 7 (and if appropriate also the second flat surfaces of the second stator cover 8) to be ground or finished.

The grinding or finishing of the first

flat surfaces

31, 33 of the stator 6 and the rotor 7 can be carried out using conventional grinding or finishing devices known from the prior art. In particular, grinding or finishing of these surfaces is used to produce a surface roughness Rz of less than 16 μm, in particular between 1 μm and 14 μm, in accordance with DIN EN ISO 4287.

The first planes 31, 33 of the stator 6 and the rotor 7 may also be calibrated only. The calibration can likewise be carried out using known calibration devices, for example by means of a calibration negative die (kalibrierrmatrize). In the calibration, the sintered component is subjected to high pressure in or with a calibration tool, so that component inaccuracies can be reduced or eliminated on the basis of the accuracy of the calibration negative mold. In particular, the surface roughness Rz to DIN EN ISO 4287 of less than 30 μm, in particular between 4 μm and 28 μm, is produced by means of calibration of the surfaces.

In this case, according to one embodiment of the method, it can be provided that the stator 6 and/or the rotor 7 are calibrated before grinding, in particular in a calibration die of a press.

The stator 6 and the rotor 7 can be ground separately from each other. However, according to a further embodiment variant, it can be provided that the rotor 7 and the stator 6 are arranged on a clamping device and that the

planes

31, 33 to be ground are ground together. In this case, the layer thicknesses of the rotor 7 and the stator 6 are removed on the

flat surfaces

31, 33. The layer thickness may be, for example, between 1 μm and 80 μm. In order to be able to remove the material of the stator 6 and the rotor 7 in this range, at least the layer thickness is taken into account when producing the stator 6 and the rotor 7, i.e. the two components (viewed in the axial direction 21) are produced at least above this layer thickness.

In the embodiment variant in which the stator 6 and the rotor 7 are ground together, it is advantageous if these two components are then also packaged together and provided as a kit to the end user together with the stator cover 8, since the stator 6 and the rotor 7 can be better matched to one another by grinding together and therefore together with the stator cover 8 a system with smaller tolerances can be formed.

Preferably, both the stator 6 and the rotor 7 of the camshaft adjuster 2 are formed as sintered components. However, it is also possible to produce the stator 6 and/or the rotor 7 from a solid material, for example a cast material.

All descriptions of the standards in this specification relate to the final effective text at the time of application based on the priority application, unless explicitly stated otherwise.

The exemplary embodiments show possible embodiments of the camshaft adjuster 2 or of the components thereof, it being noted here that combinations of the individual embodiments with one another are also possible.

For the sake of clarity, it should finally be pointed out that these are not necessarily shown to scale in order to better understand the camshaft adjuster 2 or its elements.

List of reference numerals:

1 internal combustion engine

2 camshaft adjuster

3 driving wheel

4 face tooth

5 face tooth part

6 stator

7 rotor

8 stator cover

9 stator base

10 peripheral surface

11 slat

12 gap part

13 circumferential direction of the shaft

14 rotor base

15 peripheral surface

16 wing part

17 side surface

18 work space

19 working chamber

20 working chamber

21 axial direction

22 receiving part

23 cover body

24 end face

25 end face

26 facing surface

27 height

28 projection

29 width

30 holes

31 plane

32 end face

33 plane

34 end face

35 annular lath

Claims

1. Stator cover (8) for a stator (6) of a camshaft adjuster (2), comprising a cover body (23) having a first end face (24) which forms an abutment face (26) with which the cover body (23) can be brought into abutment against the stator (6), characterized in that at least 40% of the abutment face (26) is formed so as to be raised relative to the remainder of the first end face (24).

2. Stator cover (8) according to claim 1, characterized in that the raised area of the contact surface (26) is designed as a plane.

3. Stator cover (8) according to claim 1 or 2, characterized in that the raised abutment surface (26) protrudes with respect to the rest of the first end surface (24) by a height (27) selected from the range of 2 μm to 100 μm.

4. Stator cover (8) according to one of claims 1 to 3, characterized in that only one raised contact surface (26) is formed, which extends over 360 ° of the cover body (23).

5. Stator cover (8) according to one of the claims 1 to 4, characterized in that the cover body (23) is made of a sintered material.

6. Stator cover (8) according to one of claims 1 to 5, characterized in that the abutment surface (26) is hardened.

7. Stator cover (8) according to one of the claims 1 to 6, characterized in that the abutment surface (26) is not ground.

8. Camshaft adjuster (2), in particular hydraulic camshaft adjuster (2), comprising a stator (6) and a rotor (7), the rotor (7) being arranged at least partially, in particular integrally, within the stator (6), and a stator cover (8) which is connected to the stator (6), characterized in that the stator cover (8) is formed according to one of claims 1 to 6.

9. Camshaft adjuster (2) according to claim 8, characterized in that the contact surface (26) of the stator cover (8) is provided only in the region of the first end face (24) that directly contacts the stator (6).

10. Method for producing a camshaft adjuster (2), in particular a hydraulic camshaft adjuster, comprising:

a stator (6) having a stator base body (9) which is produced with outer end face teeth (4), a radially inner circumferential surface (10) and strips (11) which project radially inwards from the radially inner circumferential surface (10) and are spaced apart from one another in a circumferential direction (13) of the stator base body (9);

a rotor (7) which can be rotated relative to the stator (6) and which has a rotor base body (14) which is at least partially surrounded by the stator (6) and which is produced with limbs (16) which project radially outwards from a radially outer circumferential surface (15), so that a plurality of hydraulic working spaces (18) are formed between the stator (6) and the rotor (7), which are each divided by the limbs (16) of the rotor (7) into a first working chamber (19) and a second working chamber (20);

the stator (6) and the rotor (7) are produced with a first plane (31, 33) on a first end face (32, 34);

the rotor (7) and/or the stator (6) are produced according to a powder metallurgy method;

characterized in that the first flat faces (31, 33) of the stator (6) and rotor (7) are ground or finished, in particular co-ground, and that the stator (6) and rotor (7) are thereafter covered with a stator cover (8) according to one of claims 1 to 6.