Method for producing a camshaft adjuster

Abstract

A camshaft adjuster is produced that includes a stator and a rotor, which is rotatable relative to the stator, wherein the stator and the rotor are produced with first planar surfaces on a first end face and with second planar surfaces on a second end face, which is formed to be opposite the first end face when viewed in an axial direction and wherein the rotor and/or the stator is or are produced according to a powder-metallurgical method, The first planar surfaces and the second planar surfaces of the stator and the rotor are ground or finished, and the lateral surface of the stator and the lateral surface of the rotor are left uncalibrated.

Claims

1. A method for producing a hydraulic camshaft adjuster, the method comprising (a) producing a stator including: a stator base body formed with an outer spur gearing and a radially inner lateral surface, a plurality of webs protruding radially inwards from the radially inner lateral surface, the plurality of webs being circumferentially arrayed about the stator base body, and a first stator planar surface on a first axial end face of the stator base body, and a second stator planar surface on a second axial end face of the stator base body opposite the first axial end face of the stator base body; (b) producing a rotor configured to rotate relative to the stator, the rotor including: a rotor base body at least partially arranged in the stator so as to define a plurality of hydraulic working spaces respectively formed between adjacent webs of the plurality of webs, a plurality of blades protruding radially outwards from a radially outer lateral surface of the rotor base body so as to respectively divide each hydraulic working space into a first working chamber and a second working chamber, and a first rotor planar surface on a first axial end face of the rotor base body, and a second rotor planar surface on a second axial end face of the rotor base body opposite the first axial end face of the rotor base body and the first axial end face of the stator base body; and (c) grinding the first stator planar surface, the second stator planar surface, the first rotor planar surface, and the second rotor planar surface while a remaining portion of the stator base body and the rotor base body are left uncalibrated; wherein the grinding of the first stator planar surface and the first rotor planar surface is performed concurrently with the rotor and the stator arranged on a common clamping device.

2. The method according to claim 1, wherein the grinding of the second stator planar surface and the second rotor planar surface is performed concurrently with the rotor and the stator arranged on the common clamping device.

3. The method according to claim 1, wherein three support elements are formed on at least one of the second stator planar surface and the second rotor planar surface, and wherein the first stator planar surface and the first rotor planar surface are ground before the three support elements are removed and the second stator planar surface and the second rotor planar surface are ground.

4. The method according to claim 3, wherein the three support elements are formed in one piece with the at least one of the second stator planar surface and the second rotor planar surface.

5. The method according to claim 3, wherein the three support elements are produced from a material that is configured to plastically deform during assembly of the camshaft adjuster.

6. The method according to claim 3, wherein the three support elements are produced from a polymer-based material.

7. The method according to claim 3, wherein the three support elements are formed to be knob-shaped.

8. A hydraulic camshaft adjuster comprising: a single-piece rotor made from a sintering material, the rotor including: a rotor base body; a plurality of blades protruding radially outwards from a radially outer lateral surface of the rotor base body; and a first rotor planar surface on a first axial end face of the rotor base body, and a second rotor planar surface on a second axial end face of the rotor base body opposite the first axial end face of the rotor base body, and a single-piece stator made from a sintering material, the stator including: a stator base body formed with an outer spur gearing and a radially inner lateral surface; a plurality of webs protruding radially inwards from the radially inner lateral surface, the plurality of webs being circumferentially arrayed about the stator base body; and a first stator planar surface on a first axial end face of the stator base body, and a second planar surface on a second axial end face of the stator base body opposite the first axial end face of the stator base body, wherein the first stator planar surface and the second stator planar surface are ground while a remaining portion of the stator base body is left uncalibrated, and wherein the grinding of the first stator planar surface and the first rotor planar surface is performed concurrently with the rotor and the stator arranged on a common clamping device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For the purpose of better understanding of the invention, it will be elucidated in more detail by means of the figures below.

(2) These show in a simplified schematic representation:

(3) FIG. 1 shows a cutout from a combustion engine;

(4) FIG. 2 shows a cutout from a hydraulic camshaft adjuster in a longitudinal section;

(5) FIG. 3 shows the stator and the rotor of the camshaft adjuster according to FIG. 2 in an oblique view;

(6) FIG. 4 shows the stator and the rotor of the camshaft adjuster according to FIG. 2 in a front view;

(7) FIG. 5 shows a control valve;

(8) FIG. 6 shows the common arrangement of a stator and a rotor in a clamping device; and

(9) FIG. 7 shows an embodiment variant of a rotor.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(10) First of all, it is to be noted that in the different embodiments described, equal parts are provided with equal reference numbers and/or equal component designations, where the disclosures contained in the entire description may be analogously transferred to equal parts with equal reference numbers and/or equal component designations. Moreover, the specifications of location, such as at the top, at the bottom, at the side, chosen in the description refer to the directly described and depicted figure and in case of a change of position, these specifications of location are to be analogously transferred to the new position.

(11) FIG. 1 shows a cutout from a combustion engine 1. A hydraulic camshaft adjuster 2 and a drive wheel 3 are shown. The camshaft adjuster 2 has a spur gearing 4 on its outer circumference. The drive wheel 3 also has a spur gearing 5 on its outer circumference. The two spur gearings 4, 5 are arranged in a meshing engagement with one another.

(12) The spur gearing 4 of the camshaft adjuster 2 can also be configured for engaging with a timing chain or a driving belt (not shown).

(13) In principle, this configuration of hydraulic camshaft adjusters 2 is known from the prior art, so that further explanations regarding this can be dispensed with.

(14) As can be seen in FIGS. 2 to 4, the camshaft adjuster 2 has a stator 6 and a rotor 7. The representation of a covering 8 on the front side of the camshaft adjuster 2 that can be seen in FIG. 1 was dispensed with in FIGS. 3 and 4.

(15) The stator 6 has an annular stator base body 9, which has the outer toothing in the form of the spur gearing 4 on its outer circumference—as previously mentioned. Webs 11 are formed on a radially inner lateral surface 10 of the stator base body 9 so as to protrude radially inwards beyond said lateral surface 10. In the particular case, the stator 6 has four webs 11. This number of webs 11, however, is not to be understood as limiting. It is also possible for more or fewer webs 11 to be present. The webs 11 may optionally be provided with a recess 12 and/or an opening in order to lower the weight of the stator 6. The webs 11 are arranged on the stator base body 9 so as to be distanced from one another in a circumferential direction 13.

(16) Within the stator 6, the rotor 7 is completely arranged and/or at least partially arranged—as mentioned before, the representation of the coverings 8 (FIG. 1) was omitted. The rotor 7 has an (annular) rotor base body 14. On an outer lateral surface 15 of said rotor base body 14, blades 16 are formed and/or arranged, which extend radially outwards starting from the lateral surface 15. In an assembled state of the camshaft adjuster 2, said blades 16 are arranged between the webs 11 of the stator 6. In this regard, side surfaces 17 of the webs 11 form the stop faces for the blades 16 of the rotor 7, as it is evident from FIG. 3.

(17) The number of blades 16 of the rotor 7 is determined by the number of webs 11 of the stator 6, with the result that, in the specific case, thus four blades 16 are present.

(18) The webs 11 define hydraulic working spaces 18. One working space 18 each is limited in the circumferential direction 13 by two webs 11. The blades 16, which are arranged between the webs 11, divide the working spaces 18 into a first working chamber 19 and a second working chamber 20, in each case by means of one blade 16 of the rotor 7. The relative position of the rotor 7 to the stator 6 can be changed by means of the fluid which can be introduced into said working chambers 19, 20, as it is known per se, so that regarding this, reference is made to the relevant prior art.

(19) It should be noted that the hydraulic embodiment of the camshaft adjuster 2 is the preferred one. However, the camshaft adjuster 2 can also be designed differently.

(20) The rotor 7 is thus arranged within the stator 6 so as to be rotatable (pivotable) relative to the stator 6 in the circumferential direction 13, wherein the path of the rotatability (pivotability) is limited by the webs 11. The camshaft adjuster 2 thus works according to the principle of a swivel motor. Driven by a chain or a belt drive or the drive wheel 3, the camshaft adjuster 2 adjusts the opening and closing times of the gas exchange valves at an earlier or later time with respect to the driving shaft, such as the crankshaft, in order to influence on the combustion process in the internal combustion engine. In this regard, the camshaft is adjusted either in the direction “early” or in the direction “late” by filling the opposing working chambers 19, 20 forming between the rotor 7 and the stator 6 of the camshaft adjuster 2 with a suitable hydraulic medium.

(21) A control valve 23 (which may also be referred to as central valve) is arranged at least partially inside a recess 22 of the rotor 7 extending in an axial direction 21 and/or particularly passing through the rotor 7, meaning so as to be at least partially surrounded by the rotor 7.

(22) FIG. 5 shows an embodiment variant of the control valve 23. Said control valve 23 has multiple conical or cylindrical sections 24 to 26 with openings 27 (bores), through which the hydraulic fluid can be fed into and/or discharged from the working chambers 19, 20, depending on the position of a piston 28. A circuit for the hydraulic fluid (in particular, an oil) is adumbrated with arrows 29 in FIG. 2.

(23) The piston 28 may be actuated magnetically, for instance.

(24) For the sake of completeness, it should be mentioned that the working spaces 18 and thus also the working chambers 19, 20 are limited radially inwards by a surface 30 of the rotor base body 14 (in particular by its lateral surface 15) and radially outwards by a surface 31 of the stator base body 9 (in particular by its lateral surface 10).

(25) Furthermore, seals may be arranged on the blades 16, which seals seal a distance between the blades 16 and the surface 30 (in particular the lateral surface 10) during operation of the hydraulic camshaft adjuster 2. These seals may be arranged partially inside the blades 16, for which purpose the blades 16 may have slits, as is adumbrated in dashed lines in FIG. 4.

(26) Feeding the hydraulic fluid to the working chambers 19, 20 can be carried out by means of a camshaft 32, which is arranged on the camshaft adjuster 2.

(27) For conducting the hydraulic fluid, corresponding channels and/or lines may be provided and/or arranged in components of the camshaft adjuster 2 and/or the camshaft 32.

(28) The rotor 7 preferably is a single-piece component, preferably a sintered component, so that the blades 16 thus form a single, integral component, in particular a sintered component, with the rotor base body 14.

(29) Likewise, the stator 6 preferably is a single-piece component, preferably a sintered component.

(30) For further details on hydraulic camshaft adjusters 2, which are not related to the invention, reference is made to the relevant prior art.

(31) The production of the rotor 7 is preferably carried out using a powder-metallurgical method. This method comprises the method steps:

(32) providing a first powder for producing the rotor 7 in a mold cavity of a mold;

(33) pressing the first powder to form a rotor green compact in the mold;

(34) possibly green machining the rotor green compact;

(35) sintering the rotor green compact;

(36) post-processing the rotor by means of material removal;

(37) The stator 6 is also preferably a single-piece component, in particular a sintered component (meaning it was produced from a sintering material according to a powder-metallurgical method), so that the spur gearing 4 and the webs 11 thus form a single, integral component, in particular a sintered component, with the base body 9. This method comprises the method steps:

(38) providing a second powder for producing the stator 6 in a mold cavity of a mold;

(39) pressing the second powder to form a stator green compact in the mold;

(40) possibly green machining the stator green compact;

(41) sintering the stator green compact;

(42) post-processing the stator 6 by means of material removal;

(43) possibly hardening the spur gearing 4 of the stator 6.

(44) The green machining and/or the post-processing by means of material removal of the stator 6 and/or of the rotor 7 can be carried out for example by sanding, lapping, honing etc.

(45) The hardening of the spur gearing 4 can be carried out for example by inductive hardening, quench hardening, case-hardening etc.

(46) The sintering process of the stator 6 and/or the rotor 7 can have one or multiple stages. Moreover, it can be carried out at a temperature of 700° C. to 1300° C. for a period of 10 minutes to 120 minutes, for instance.

(47) As the powder-metallurgical production of sintered components is known per se from the prior art, reference is made to the relevant prior art in order to avoid repetitions in this regard.

(48) The stator 6 has first planar surfaces 33 which are formed on a first end face 34 of the stator 6. The rotor 7 also has first planar surfaces 35 which are formed on a first end face 36 of the rotor 7. The first planar surfaces 33 of the stator 6 are arranged in an aligning manner to the first planar surfaces 35 of the rotor 7 within the tolerances, as is shown in particular in FIGS. 3 and 4.

(49) The first planar surfaces 33 of the stator 6 are formed on the webs 11, and in the embodiment variant shown, they are formed on an annular web 37 of the stator base body 9, wherein these first planar surfaces 33 of the stator 6 extend at least over the entire end faces of the webs 11 and the annular web 37 in the embodiment variant shown. The first planar surfaces 33 of the stator 6 may, however, also extend over only a part of said surfaces, for example if the webs 11 are graduated.

(50) The first planar surfaces 35 of the rotor 7 are formed on the blades 16, and in the embodiment variant shown, they are formed on the end faces 36 of a hollow cylinder 38 of the rotor base body 14 (and/or which forms the rotor base body 14), wherein these first planar surfaces 35 of the rotor 7 extend at least over the entire end faces of the blades 16 and the hollow cylinder 38 in the embodiment variant shown. The first planar surfaces 35 of the rotor 7 may, however, also extend over only a part of said surfaces, for example if the blades 16 or the hollow cylinder 38 are graduated.

(51) Opposite the first planar surfaces 33, 35 of the stator 6 and/or rotor 7 in the axial direction 21, the stator 6 has second planar surfaces 39 and the rotor 7 has second planar surfaces 40. The second planar surfaces 39 of the stator 6 are formed on second end faces of the stator 6, and the second planar surfaces 39 of the rotor 7 are formed on second end faces of the rotor 7. The second end faces of the stator 6 and of the rotor 7 are located opposite the first end face 34 of the stator 6 and the first end face 36 of the rotor 7 in the axial direction 21 and delimit the stator base body 9 and/or the rotor base body 14 on their second side. These second planar surfaces 39 of the stator 6, as well, are arranged in an aligning manner to the second planar surfaces 40 of the rotor 7 within the tolerances. They may form the entire second end faces of the stator 6 and/or the rotor 7 or only a part thereof. The second planar surfaces 39 of the stator 6 and the second planar surfaces 40 of the rotor 7 abut on a covering 41 of the camshaft adjuster 2, in particular in a sealing manner (within the tolerances), which covering 41 is connected, for example screwed, to the stator 6.

(52) It is provided that the first planar surfaces 33, 35 and the second planar surfaces 39, 40 of the stator 6 and the rotor 7 are ground or finished. Preferably, only the first planar surfaces 33, 35 and the second planar surfaces 39, 40 of the stator 6 and the rotor 7 are ground or finished.

(53) In other words, the sealing surfaces of the stator 6 and the rotor 7 are ground on both sides (viewed in the axial direction 21).

(54) The lateral surface 9 of the stator 6, on which the webs 11 are arranged, and the lateral surface 15, on which the blades 16 are arranged, are not calibrated, preferably, these surfaces are completely unprocessed, for example by these surfaces being produced to net shape or near net shape quality. Preferably, the entire stator base body 9 and the entire rotor base body 14 are uncalibrated. However, it is possible that the outer toothing of the stator 6 (however, not its lateral surface 9) is calibrated.

(55) Grinding and/or finishing the first planar surfaces 33, 35 and the second planar surfaces 39, 40 of the stator 6 and the rotor 7 may be carried out using conventional grinding devices and/or finishing devices known from the prior art. In particular, grinding and/or finishing these surfaces produces a surface roughness Rz according to DIN EN DIN EN ISO 4287 of less than 16 μm, in particular between 1 μm and 14 μm.

(56) FIG. 6 shows an embodiment variant of the method. It is possible that the stator 6 and the rotor 7 are ground separately from each other. However, according to this embodiment variant, it is provided that the rotor 7 and the stator 6 are arranged on a clamping device 42 and the planar surfaces 33, 35 and/or 39, 40 to be ground are ground together. In this process, a layer thickness 43 of the rotor 7 and the stator 6 are removed on these planar surfaces 33, 35 and/or 39, 40. This layer thickness 43 may for example amount to between 1 μm and 80 μm. In order to make the material removal of the stator 6 and the rotor 7 possible to this extent, at least these layer thicknesses 43 are taken into account in the production of the stator 6 and the rotor 7, i.e. these two components are produced being higher (viewed in the axial direction 21) by at least these layer thicknesses 43 (i.e. in each case, twice the layer thickness 43 for the stator 6 and the rotor 7).

(57) It should be noted that with the clamping device 42 shown in FIG. 6, only one side can be processed, and subsequently a reclamping operation has to take place for processing the second sides of the rotor 7 and the stator 6. However, a clamping device 42 allowing the simultaneous grinding of the stator 6 and the rotor 7 from both may also be used.

(58) In the embodiment variant of joint grinding of the stator 6 and the rotor 7 it is advantageous if these two components are also subsequently packaged together and delivered to the end consumer as a set, as the stator 6 and the rotor 7 can be better coordinated with each other due to the joint grinding.

(59) FIG. 7 shows an embodiment variant of the rotor 7. In this embodiment variant, multiple support elements 44 are provided on the rotor base body 14.

(60) During the pressing of the powder, at least three support elements 44 may also be formed on the green compact for the rotor 7, on the first or second planar surfaces 34 or 40 not to be ground, so as to protrude beyond them in the axial direction 21. Preferably, exactly three support elements 44 are formed. However, more than three support elements 44 may also be formed, for example four, five, six etc.

(61) For forming the elevations on the green compact, a punch in particular is used for pressing the powder, which has corresponding recesses where the support elements 44 are.

(62) As can be seen in FIG. 7, the support elements 44 are not arranged in one line, i.e. not on a straight line. In fact, in the case of three support elements 44, the support elements 44 are arranged and/or formed at the corner points of an equilateral triangle, i.e. in each case offset to each other by 120°, according to a preferred embodiment variant.

(63) It is further preferred for the support elements 44 to be arranged on the planar surfaces 35, 40 at the same radial height, as can also be seen in FIG. 7.

(64) In principle, the support elements 44 may be arranged at any suitable location on the planar surfaces 35, 40 or also on the rotor base body 14.

(65) The support elements 44 may also be formed to be cylindrical. However, they may also have a different shape, in particular a hemispherical shape or the shape of a spherical cap or a cuboidal shape or a pyramidal shape etc. Preferably, they are formed to be knob-shaped.

(66) Preferably, all support elements 44 of the rotor 7 have the same shape. However, it is also possible to provide mixed variants, so that, for example, a part of the support elements 44 is cylindrical and the rest is formed in the shape of a spherical cap. Other mixed variants are also conceivable.

(67) The support elements 44 thus extends/extend over at least a partial area of the respective planar surface 35 or 40 of the rotor, wherein they preferably take up a relatively small space, so that reference may also be made to support points. For this purpose, the support elements 44 may each have a maximum cross-sectional area which is selected from a range of 1 mm.sup.2 to 10 mm.sup.2, viewed in the axial direction.

(68) The support elements 44 may be produced with a maximum height, measured from the respective planar surface 35 or 40 of the rotor, which height is selected from a range of 1 μm to 80 μm, in particular from a range of 2 μm to 20 μm.

(69) The support elements 44 may also be formed to be approximately strip-shaped, so that they thus have a length greater than the width, although this is not the preferred embodiment variant.

(70) Generally, the embodiments regarding the support elements 44 may also be applied to the stator 6, so that the stator 6 may thus also have such support elements 44 on the planar surfaces 33 or 39 not to be ground.

(71) However, in addition to this single-piece embodiment variant of the support elements 44 with the rotor 7 and/or the stator 6, it is also possible, according to further embodiment variants, to arrange them separately on it/them, in particular after sintering the rotor 7 and/or the stator 6. For this purpose, the support elements 44 may be made, for example from a film and be glued to the respective planar surfaces 33, 35 or 39, 40. The support elements 44 may also be sintered onto the rotor 7 and/or the stator 6 as separate elements and/or be connected thereto in a different manner.

(72) According to a different embodiment variant, the support elements 44 may be produced as a partial coating or print made of a polymer-based material. For example, the support elements 44 may be produced from a polyamide resin, in which at least one solid lubricant, such as graphite or molybdenum disulfide, may be contained. The resin is hardened, for example thermally or by means of UV radiation, after or during the application onto the relevant areas. This embodiment variant of the support elements 44 has the advantage that the support elements 44 can be removed relatively easily from the stator 6 and/or from the rotor 7, and/or possibly even come off automatically.

(73) That is to say that the support elements 44 are removed after the first or second planar surfaces 33, 34, 39, 40 of the stator 6 and/or the rotor 7 are ground or finished.

(74) The removal may be carried out, for example, by means of machining methods or by brushing etc.

(75) After removing the support elements 45, the planar surfaces 33, 34, 39, 40, from which said support elements 45 were removed, are ground or finished.

(76) According to a further embodiment variant of the invention, it may be provided that the support elements 44 are made from a material that is plasticizable during the assembly of the camshaft adjuster 2. Here, plasticizable means that the support elements 44 are plastically deformable. This may be achieved by the support elements 44 being produced from a softer material than the rest of the stator 6 or the rotor 7. As an alternative or in addition to this, it is also possible to produce the support elements 44 having cavities, for example having pores, which are at least partially compressed upon plastic deformation. For this purpose, the support elements 44 may be made from a sintering material. As explained above, however, the entire stator 6 or rotor 7 preferably consists of the material, from which the support elements 44 are produced.

(77) Due to the plastic deformation, it is possible that the support elements 44 are at least partially compressed, whereby the effort for their removal from the planar surfaces 33, 35, 39, 40 can be reduced.

(78) Merely for the sake of completeness, it should be mentioned that the support elements 44 serve to support the stator 6 and/or the rotor 7 on a support surface, in particular a support surface of the clamping device 42, during the grinding and/or finishing of the planar surfaces 33, 35 or 39, 40.

(79) For the sake of completeness, it should be mentioned that the camshaft adjuster 2 has a covering 8, 41 on both sides (on the axial end faces), by means of which the working spaces 18 are closed in the axial direction 21.

(80) According to the described method, a single-piece stator 6 for a camshaft adjuster 2 can be produced from a sintering material, comprising a stator base body 9, which has an outer spur gearing 5, a radially inner lateral surface 10 and webs 11 protruding radially inwards from the radially inner lateral surface 10, which webs 11 are distanced from one another in the circumferential direction 13 of the stator base body 9, wherein the stator 6 has first planar surfaces 33 on a first end face 34 and second planar surfaces 39 on a second end face, which is arranged opposite the first end face 34 when viewed in the axial direction 21, wherein the first planar surfaces 33 and the second planar surfaces 39 of the stator 6 are ground or finished, and at least the lateral surface 10 is uncalibrated and unground.

(81) It is further possible to produce a single-piece rotor 7 for a camshaft adjuster 2 from a sintering material with this method, comprising a rotor base body 14, which has blades 16 protruding radially outwards from a radially outer lateral surface 15, wherein the rotor 7 has first planar surfaces 35 on a first end face 36 and second planar surfaces 40 on a second end face, which is arranged opposite the first end face 36 when viewed in the axial direction 21, wherein the first planar surfaces 35 and the second planar surfaces 40 of the rotor 7 are ground or finished, and the lateral surface 15 of the rotor 7 is uncalibrated and unground.

(82) Preferably, both the stator 6 and the rotor 7 of the camshaft adjuster 2 are formed as sintered components. However, it is also possible that the stator 6 and/or the rotor 7 consist(s) of a solid material, for example a casting material.

(83) In the case of the stator 6, the distance from the first to the second planar surfaces 33, 39 can have a tolerance of 10 μm to 25 μm.

(84) In the case of the rotor 7, the distance from the first to the second planar surfaces 35, 40 can have a tolerance of 8 μm to 25 μm.

(85) Merely for the sake of completeness, it should be noted that it is particularly preferred to use metallic powders as sintering powders.

(86) The exemplary embodiments show possible embodiment variants of the camshaft adjuster 2 and components thereof, while it should be noted at this point that combinations of the individual embodiment variants are also possible.

(87) Finally, as a matter of form, it should be noted that for ease of understanding of the camshaft adjuster 2 and/or its elements, these are not necessarily depicted to scale.

LIST OF REFERENCE NUMBERS

(88) 1 Combustion engine 2 Camshaft adjuster 3 Drive wheel 4 Spur gearing 5 Spur gearing 6 Stator 7 Rotor 8 Covering 9 Stator base body 10 Lateral surface 11 Web 12 Recess 13 Circumferential direction 14 Rotor base body 15 Lateral surface 16 Blade 17 Side surface 18 Working space 19 Working chamber 20 Working chamber 21 Axial direction 22 Recess 23 Control valve 24 Section 25 Section 26 Section 27 Opening 28 Piston 29 Arrow 30 Surface 31 Surface 32 Camshaft 33 Planar surface 34 End face 35 Planar surface 36 End face 37 Annular web 38 Hollow cylinder 39 Planar surface 40 Planar surface 41 covering 42 Clamping device 43 layer thickness 44 support element