EP2672123A1 - Cell wheel, in particular for a pressure wave charger - Google Patents

Abstract

The cellular wheel (10) is made of metal and has an outer sleeve (12) arranged coaxial to a rotational axis, an inner sleeve (14) arranged coaxial to the outer sleeve and an intermediate sleeve (18) arranged between and coaxial to the outer sleeve and the inner sleeve. The outer sleeve, the inner sleeve and the intermediate sleeve or one of the intermediate sleeves have notches (26) between adjacent fins (16), where the notches extend from the two end faces of the cellular wheel.

Description

TECHNICAL AREA

The present invention relates to a cellular wheel made of metal, with an outer sleeve lying coaxially to a rotation axis, an inner sleeve coaxial with the outer sleeve, at least one between the outer sleeve and inner sleeve coaxial with these intermediate sleeve arranged between successive sleeves, radially aligned with the axis of rotation, with adjacent sleeves joined lamellae, with the outer sleeve cross-over and with the outer sleeve joined outer sealing sleeves with a sealing profile for a labyrinth seal, and with a lying in the axis of rotation drive shaft.

STATE OF THE ART

For some years, the downsizing process has been one of the main topics in the design of new supercharged engines. With downsizing, the fuel consumption and thus the exhaust emissions of a vehicle can be reduced. Today, these goals are becoming increasingly important, as the high energy consumption of fossil fuels contributes greatly to air pollution, and ever tougher legislative measures are forcing automakers to act. Downsizing is the substitution of a large-volume engine with a displacement-reduced engine. The engine power should be kept high by charging the engine. The goal is to achieve the same performance with small-volume engines as with large-volume engines, as with naturally aspirated engines of the same performance. Recent findings in the field of downsizing have shown that the best results can be achieved, especially with very small gasoline engines with a displacement of 2 liters or less with a pressure wave charging system.

In a pressure wave supercharger, the rotor is designed as a cellular wheel and is enclosed by an air and exhaust housing with a common jacket. The development of modern pressure wave chargers for charging small engines leads to cell wheels with a diameter of the order of 100 mm or less. To obtain a maximum cell volume and also for weight reduction, cell wall thicknesses of 0.4 mm or less are desired. At the high exhaust gas inlet temperatures of about 1000 ° C come as materials for the feeder virtually only high-temperature alloys in question. The production of dimensionally stable and high-precision cellular wheels with a small cell wall thickness is today hardly possible or associated with considerable additional costs.

It has already been proposed to form the chambers of a cellular wheel of juxtaposed and partially overlapping, Z-shaped profiles. However, the production of such a cellular wheel is associated with high expenditure of time. In addition, the juxtaposition and positionally accurate fixing of Z-profiles hardly feasible with a sufficient to comply with the required tolerances precision.

It has also been proposed to produce a cellular wheel from a solid body by eroding the individual cells. With this method, however, it is difficult to achieve cell wall thicknesses of less than 0.5 mm. Another major disadvantage of the erosion process are the associated high material and processing costs.

A cellular wheel of the type mentioned is in WO 2010/057319 Al disclosed. In running tests under operating conditions, it has been found that the temperature changes occurring in rapid succession in the interior of the cell wheel in the region of the end faces of the cell wheel lead to periodically strongly fluctuating thermal expansions and contractions of the disks in the radial direction with temperature differences of 200 to 300 ° C. As a result, arranged between successive sleeves and joined to the sleeves slats are exposed to high load changes with a vibration frequency in the order of twice the speed of the cell wheel, which under continuous thermal stress to cracking near the joints between Slats and sleeves can lead to the end faces of the cellular wheel and in consequence to the breaking out of fin parts and the failure of the cell wheel.

PRESENTATION OF THE INVENTION

The invention is based on the object, simple and inexpensive to manufacture a cellular wheel of the type mentioned while avoiding cracking in the joining region between fins and sleeves with the required precision. Another object of the invention is to provide a suitable for use in a pressure wave supercharger for supercharging internal combustion engines, in particular for supercharging small gasoline engines with a displacement in the order of 2 liters or less, suitable cellular wheel. In particular, mechanically stable cell wheels with a cell wall thickness of 0.5 mm or less should be able to be produced under operating conditions without a tendency to crack formation in the joining region between lamellae and sleeves.

For solving the problem according to the invention, at least the outer sleeve, the inner sleeve and / or the intermediate sleeve or, in the case of more than one intermediate sleeve, at least one of the intermediate sleeves has cut-outs extending from both end faces of the cellular wheel between adjacent lamellae. The incisions are preferably rotationally symmetrical.

To solve the problem of the invention also leads that exclusively the at least one intermediate sleeve of the two end faces of the cell wheel outgoing incisions. Consequently, here the outer sleeve and the inner sleeve are formed without cuts. Preferably, in each case an incision is present on the left and right of a lamella, or there is preferably always an incision between two adjacent lamellae. The incisions arranged in the intermediate sleeve thereby provide an edge strip for the corresponding lamella which is designed to be elastically movable with respect to the intermediate sleeve and other edge strips and advantageously compensates for the deformation of the lamellae resulting from temperature fluctuations by a movement of the edge strip in a substantially radial direction. As a result, the alternating bending stresses in the lamella are reduced to a great extent. The edge strips can also be referred to as tabs. Preferably, two adjacent incisions form one of the corresponding sleeve associated edge strips, wherein a single edge strip is assigned in each case a single lamella. Such an edge strip is elastically movable relative to the corresponding sleeve and to adjacent edge strips.

The incisions are preferably distributed uniformly over the circumference of the relevant sleeve. Another distribution depending on the arrangement of the slats is also conceivable.

Preferably, cuts are present between all adjacent lamellae. However, it is also possible to provide fewer cuts over the sleeve circumference. For example, an incision may be provided after every second or third lamella.

By arranged between joints of adjacent lamellae with the outer, inner and / or intermediate sleeve incisions, the sleeve in question in the edge region of the feeder is thus divided into edge strips, so that adjacent edge strips in the radial direction are mutually displaceable. As a result, the lamellae, together with the edge strips joined with the lamellae, can expand and contract in the radial direction from their original position in the sleeve, so that the thermal expansions and contractions of the lamellae occurring in rapid succession in the radial direction result in less stress build-up and degradation By fast load changes in the slats in the area of their joints with the outer, inner and / or intermediate sleeves and with this measure material damage can be avoided.

To avoid stress peaks at the ends of the incisions and an associated formation and further propagation of a crack may be provided as a so-called tear stopper at the ends of the incisions a recess. The recess can have a round or elliptical cross-section perpendicular to the central axis in plan view. The extent of the recess is preferably in the range 1 to 2 mm.

In a first embodiment of the inventive cell wheel, the inner sleeve is seated on a coaxially arranged to this, joined to the drive shaft flange sleeve and the outer sleeve has from both end faces of the cellular wheel outgoing incisions between adjacent lamellae. A remote from the end faces of the cellular wheel peripheral edge of the outer sealing sleeves extends beyond the cuts by a measure and the outer sealing sleeves are joined only in the incision projecting area with the outer sleeve.

Preferably, the sealing profile of the outer sealing sleeves has a sealing surface aligned with the end faces of the cellular wheel, and the outer sealing sleeves form, with the outer sleeve, an annular gap open at the end faces of the cellular wheel.

Preferably, in this first embodiment, the inner sleeve of both end faces of the cell wheel outgoing incisions between adjacent lamellae. The inner sleeve is hereby joined with the flange sleeve between adjacent lamellae between opposed incisions.

In a second, preferred embodiment of the cell wheel according to the invention, the inner sleeve is joined to the drive shaft and the intermediate sleeve or, in the case of two or more intermediate sleeves, at least one of the intermediate sleeves has incisions extending between both end faces of the cellular wheel between adjacent lamellae.

Preferably, in this second embodiment, the sealing profile of the outer sealing sleeves on a flush with the end faces of the cellular wheel sealing surface and in the inner sleeve are fitted with the inner sleeve inner sealing sleeves arranged with a sealing profile with an aligned with the end faces of the cell wheel sealing surface for a labyrinth seal.

Preferably, in the second embodiment, the sealing sleeves are joined only in the region of the remote from the end faces of the cellular wheel end with the outer and inner sleeve and form with the outer and inner sleeves open at the end faces of the cellular wheel annular gap.

The sealing surface of the sealing profile and the annular gap adjacent to the sealing surface between the sealing sleeve and outer or inner sleeve are decisive for the tightness of a labyrinth seal between the end faces of the cell wheel and the control surfaces of the gas and air housings facing one another in a pressure wave loader. The pressure waves acting periodically on the end faces of the cellular wheel also lead to high gas pressures in the area of the labyrinth seals. The annular gap adjoining the sealing surface of the sealing profile prevents, with a slight local pressure reduction when the gas flows into the annular gap, an escape of gas through the gap formed between the sealing surface and the opposing control surface and thus a pressure loss which reduces the power of the pressure wave supercharger.

In order to stabilize the annular gap, spacer elements arranged distributed over the circumference of the sealing sleeves can protrude from the side of the sealing sleeves facing the outer or inner sleeve in the region of the end faces of the cellular wheel. Alternatively, the spacer elements can be distributed over the circumference of the outer or inner sleeve on the side facing the sealing sleeve side of the outer or inner sleeve.

Due to their reduced mass, the above-described embodiment of the sealing sleeves with the outer and inner sleeves forming an annular gap at the end faces of the cellular wheel also leads to smaller centrifugal forces and thus to a higher dimensional stability of the cellular wheel with a correspondingly improved seal.

The length of the incisions in the outer sleeve, the inner sleeve or the intermediate sleeve or in more than one intermediate sleeve in at least one of the intermediate sleeves is in the range of about 10% to 30% of the length of the cellular wheel, i. the distance between the two end faces of the cellular wheel.

Preferably, the outer sleeve, the inner sleeve, the intermediate sleeve / s, the fins and the sealing sleeves are made of sheet metal with a thickness of less than 0.5 mm.

In a particularly preferred second embodiment of the inventive cell wheel, the drive shaft has two coaxial with the drive shaft and arranged spaced-apart annular webs with a peripheral surface as bearing surfaces for the inner sleeve and at least one of the annular webs is joined to the inner sleeve.

Conveniently, the remote from the end faces of the cellular wheel end of the inner sealing sleeves is joined to one of the annular webs.

As heat protection, the inner sealing sleeve on the hot gas side, i. be joined on the side of the exhaust housing, at the end face of the cellular wheel with a lid. Alternatively or additionally, the hot gas side near ring web can be joined with a lid.

With these measures, the drive axle can be kept at a relatively low temperature under operating conditions of a pressure wave supercharger, so that the axial play of the enclosed between gas and air housing cellular wheel to maintain a minimum clearance of about 0.03 to 0.05 mm over the entire speed range can be set smaller in the cold operating state.

For weight reduction, the drive shaft is designed as a hollow shaft with a tubular end part, a conical intermediate part and a tubular shaft part with a receptacle for a to be connected to a motor drive coupling.

For further weight reduction, the tubular end part and the conical intermediate part expediently have openings arranged symmetrically over the circumference, which also allow an air circulation corresponding cooling effect.

The coupling piece preferably has a coupling axis with longitudinal ribs, which engage in insertion of the coupling piece into the receptacle of the tubular shaft part in longitudinal grooves in the receptacle.

The inventive cellular wheel is preferably used in a pressure wave supercharger for supercharging internal combustion engines, in particular gasoline engines with a displacement of preferably 2 liters or less.

BRIEF DESCRIPTION OF THE DRAWING

Fig. 1

eine Sicht auf eine Stirnfläche des in Fig. 4 dargestellten Zellenrades für einen Druckwellenlader;

Fig. 2

einen Längsschnitt durch das auf eine Flanschhülse einer Antriebswelle aufgesetzte Zellenrad von Fig. 4 nach der Linie I-I in Fig. 1;

Fig. 3

einen Längsschnitt durch das auf eine Flanschhülse einer Antriebswelle aufgesetzte Zellenrad von Fig. 4 nach der Linie II-II in Fig. 1;

Fig. 4

eine perspektivische Ansicht einer ersten Ausführungsform eines Zellenrades für einen Druckwellenlader;

Fig. 5

einen Teilbereich III des Zellenrades von Fig. 4 in vergrösserter Darstellung;

Fig. 6

einen Teilbereich IV des Längsschnittes des Zellenrades von Fig. 3 in vergrösserter Darstellung;

Fig. 7

eine perspektivische Ansicht einer Lamelle des Zellenrades von Fig. 4;

Fig. 8

einen Teilbereich V der Lamelle von Fig. 7 in vergrösserter Darstellung;

Fig. 9

eine Sicht auf eine Stirnfläche des in Fig. 15 dargestellten Zellenrades für einen Druckwellenlader;

Fig. 10

einen Längsschnitt durch das auf eine Antriebswelle aufgesetzte Zellenrad von Fig. 15 nach der Linie VI-VI in Fig. 9;

Fig. 11

einen Querschnitt durch die Antriebswelle nach der Linie VII-VII in Fig. 10;

Fig. 12

einen ersten Teilbereich VIII des Längsschnittes des Zellenrades von Fig. 10 in vergrösserter Darstellung;

Fig. 13

einen zweiten Teilbereich IX des Längsschnittes des Zellenrades von Fig. 10 in vergrösserter Darstellung;

Fig. 14

einen dritten Teilbereich X des Längsschnittes des Zellenrades von Fig. 10 in vergrösserter Darstellung;

Fig. 15

eine perspektivische Ansicht einer weiteren Ausführungsform eines Zellenrades für einen Druckwellenlader;

Fig. 16

einen Teilbereich des Zellenrades von Fig. 15 in vergrösserter Darstellung;

Fig. 17

einen vergrösserten Ausschnitt der Sicht von Fig. 9 auf die Stirnfläche des in Fig. 15 dargestellten Zellenrades für einen Druckwellenlader;

Fig. 18

einen vergrösserten Ausschnitt aus Fig. 17 in einem ersten Betriebszustand des Zellenrades;

Fig. 19

einen vergrösserten Ausschnitt aus Fig. 17 in einem zweiten Betriebszustand des Zellenrades;

Fig. 20

eine perspektivische Ansicht einer äusseren Dichthülse des Zellenrades von Fig. 15;

Fig. 21

einen Axialschnitt durch die äussere Dichthülse von Fig. 20;

Fig. 22

einen Ausschnitt aus der Sicht auf die Stirnfläche der äussere Dichthülse von Fig. 20;

Fig. 23

eine perspektivische Ansicht einer ersten (heissgasseitigen) inneren Dichthülse des Zellenrades von Fig. 15;

Fig. 24

einen Axialschnitt durch die heissgasseitige innere Dichthülse von Fig. 23;

Fig. 25

eine Sicht auf die Stirnfläche der heissgasseitigen inneren Dichthülse von Fig. 24;

Fig. 26

eine perspektivische Ansicht einer zweiten (kaltgasseitigen) inneren Dichthülse des Zellenrades von Fig. 15;

Fig. 27

einen Axialschnitt durch die kaltgasseitige innere Dichthülse von Fig. 26;

Fig. 28

eine Sicht auf die Stirnfläche der kaltgasseitigen inneren Dichthülse von Fig. 27.

Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing, which is merely illustrative and not restrictive interpreted. The drawing shows schematically in

Fig. 1

a view of an end face of the in Fig. 4 shown cell wheel for a pressure wave supercharger;

Fig. 2

a longitudinal section through the attached to a flange sleeve of a drive shaft cell wheel of Fig. 4 after the line II in Fig. 1 ;

Fig. 3

a longitudinal section through the attached to a flange sleeve of a drive shaft cell wheel of Fig. 4 after the line II-II in Fig. 1 ;

Fig. 4

a perspective view of a first embodiment of a bucket for a pressure wave supercharger;

Fig. 5

a subregion III of the cellular wheel of Fig. 4 in an enlarged view;

Fig. 6

a portion IV of the longitudinal section of the cell wheel of Fig. 3 in an enlarged view;

Fig. 7

a perspective view of a blade of the cellular wheel of Fig. 4 ;

Fig. 8

a portion V of the lamella of Fig. 7 in an enlarged view;

Fig. 9

a view of an end face of the in Fig. 15 shown cell wheel for a pressure wave supercharger;

Fig. 10

a longitudinal section through the attached to a drive shaft cell wheel of Fig. 15 after the line VI-VI in Fig. 9 ;

Fig. 11

a cross section through the drive shaft along the line VII-VII in Fig. 10 ;

Fig. 12

a first portion VIII of the longitudinal section of the cell wheel of Fig. 10 in an enlarged view;

Fig. 13

a second portion IX of the longitudinal section of the cell wheel of Fig. 10 in an enlarged view;

Fig. 14

a third portion X of the longitudinal section of the cell wheel of Fig. 10 in an enlarged view;

Fig. 15

a perspective view of another embodiment of a bucket for a pressure wave supercharger;

Fig. 16

a portion of the cell wheel of Fig. 15 in an enlarged view;

Fig. 17

an enlarged section of the view of Fig. 9 on the face of the in Fig. 15 shown cell wheel for a pressure wave supercharger;

Fig. 18

an enlarged section Fig. 17 in a first operating state of the cellular wheel;

Fig. 19

an enlarged section Fig. 17 in a second operating state of the cellular wheel;

Fig. 20

a perspective view of an outer sealing sleeve of the cellular wheel of Fig. 15 ;

Fig. 21

an axial section through the outer sealing sleeve of Fig. 20 ;

Fig. 22

a section from the view of the end face of the outer sealing sleeve of Fig. 20 ;

Fig. 23

a perspective view of a first (hot gas) inner sealing sleeve of the bucket of Fig. 15 ;

Fig. 24

an axial section through the hot gas side inner sealing sleeve of Fig. 23 ;

Fig. 25

a view of the end face of the hot gas side inner sealing sleeve of Fig. 24 ;

Fig. 26

a perspective view of a second (cold gas) inner sealing sleeve of the bucket of Fig. 15 ;

Fig. 27

an axial section through the cold gas side inner sealing sleeve of Fig. 26 ;

Fig. 28

a view of the end face of the cold gas side inner sealing sleeve of Fig. 27 ,

DESCRIPTION OF PREFERRED EMBODIMENTS

One in the Fig. 1 and 4 shown cellular wheel 10 of a pressure wave supercharger not shown in the drawing consists of a concentric with a rotation axis y of the cellular wheel 10 outer sleeve 12, a concentric with the outer sleeve 12 inner sleeve 14 and a between the outer sleeve 12 and the inner sleeve 14 concentrically arranged to these intermediate sleeve 18th The outer annular space between the intermediate sleeve 18 and the outer sleeve 12 and the inner annular space between the intermediate sleeve 18 and the inner sleeve 14 are divided by radially arranged to the rotation axis y strip-shaped fins 16 into a plurality outer cells 20 and a plurality of inner cells 22. The exemplified cellular wheel 10 with a diameter D and a length L of, for example, 100 mm each has less than 60 outer cells 20 and less than 40 inner cells 22. The outer sleeve 12, the intermediate sleeve 18, the inner sleeve 14 and the fins 16 have a uniform Wall thickness of z. B. 0.4 mm and consist of a highly heat-resistant metallic material, for. Inconel 2.4856. The said parts have in the direction of the rotation axis y an equal length L corresponding to the length of the cellular wheel 10 and extend between two perpendicular to the axis of rotation y end faces 11 of the cellular wheel 10. In the region of the two end faces 11 are on the outer sleeve 12 circumferential outer sealing sleeves 24 arranged with a aligned with the end face 11 of the cellular wheel 10 sealing surface 32 of a sealing profile 30 of a labyrinth seal. The counter surfaces to the sealing surfaces 32 required for the labyrinth seal form the control surfaces of the exhaust gas and air housings which are opposite the end faces 11 of the cellular wheel 10 in a pressure wave supercharger.

That in the Fig. 1 and 4 illustrated cellular wheel 10 is according to the FIGS. 2 and 3 connected by a flange sleeve 15 with a drive shaft 13. The flange sleeve 15 is aligned concentrically with the drive shaft 13 and welded thereto. The axis of rotation of the drive shaft 13 corresponds to the axis of rotation y of the placed on the flange sleeve 15 cellular 10th

As in the 4 and 5 12, 12 incisions 26 are arranged in the outer sleeve 12 between joints 17 of adjacent lamellae 16 with the outer sleeve. These cuts 26 extend parallel to the slats 16 and extend from each end face 11 of the cellular wheel 10 over a length e of z. B. 15 mm. The cuts 26 terminate in a circular recess 28 with a diameter f of z. B. 2 mm. In addition, the at least one intermediate sleeve 16 could also be provided with corresponding cuts.

The arrangement of the outer sealing sleeves 24 is made of the 4 and 6 seen. The outer sealing sleeve 24 has a length g of z. B. 20 mm. At the end face 11 of the cellular wheel 10, the outer sealing sleeve 24 is in a perpendicular to the axis of rotation y outwardly projecting, the sealing profile 30 forming annular flange with the aligned with the end face 11 of the cellular wheel 10 sealing surface 32 having a width h of z. B. 1.5 mm over. The outer sealing sleeve 24 is seated substantially form-fitting manner on the outer sleeve 12 and projects with a free peripheral edge 25, the circular recesses 28 at the ends of the incisions 26 by a dimension m of eg 5 mm and is via two circumferential welds 34, 36 joined to the outer sleeve 12.

As in the 4 and 5 are shown, also incisions 26 are arranged in the inner sleeve 14 between joints 17 of adjacent fins 16 with the inner sleeve 14. These cuts 26 extend parallel to the slats 16 and extend from each end face 11 of the cellular wheel 10 over a length e of z. B. 15 mm. The cuts 26 terminate in a circular recess 28 with a diameter f of z. B. 2 mm.

Also, in this embodiment, optional cuts 26 can be arranged in the at least one intermediate sleeve.

The fins 16 are usually rectangular strips of constant thickness. Since the highest mechanical stresses and thus an increased cracking tendency occur in the vicinity of the joining zone, the lamellae may have a material thickening 19 in the region of their longitudinal edges ( FIGS. 7 and 8 ). The area of the lamellae 16 delimited by the two parallel longitudinal edges can be flat or, as viewed in the direction of the longitudinal axis of the lamellae 16, curved to increase its dimensional stability on one or both sides or be provided with a bead.

To produce the cellular wheel 10, the inner sleeve 14, whose inner diameter and length is matched to the outer diameter and the length of the flange 15, with the previously with the inner sleeve 14 with a longitudinal edge positionally joined and projecting radially outwardly with the free longitudinal edge fins 16 of both end faces 11 forth with the incisions 26 and at the ends thereof provided with the circular recesses 28. Subsequently, the thus processed inner sleeve 14 is placed with the radially outwardly projecting fins 16 in the axial direction y coaxially on the flange sleeve 15 and welded thereto by means of an NC-controlled laser beam between the fins 16 in the region between the opposing recesses 28. The weld can be continuous from recess to recess or only extend over a length of 3 to 5 mm after each recess 28. To achieve optimum tightness can also be in a short distance of z. B. 2 to 3 mm to the recess 28 a transverse to the adjacent Slats 16 extending transverse weld seam are set. Here, the transverse weld seam at their ends by parallel to the slats 16 extending longitudinal welds of z. B. 3 to 5 mm are added to a U-shaped weld.

In a next step, the intermediate sleeve 18, whose inner diameter and length is matched to the formed by the free longitudinal edges of the inner sleeve 14 radially outwardly projecting fins 16 outer diameter and the length of the inner sleeve 14, with the previously with the intermediate sleeve 18 with a Longitudinal edge positioned exactly joined and with the free longitudinal edge radially outwardly projecting slats 16 in the axial direction y coaxial and accurate position on the free longitudinal edges of the inner sleeve 14 radially outwardly projecting slats 16 set. Subsequently, the intermediate sleeve 18 is welded by means of a laser beam by means of a blind seam with the free end edges of the underlying fins 16 of the inner sleeve 14 to form the inner cells 22.

In a further step, the outer sleeve 12, whose inner diameter and length is matched to the outer diameter formed by the free longitudinal edges of the radially outwardly projecting from the intermediate sleeve 18 lamella 16 and the length of the intermediate sleeve 18, in the axial direction y coaxial with the free longitudinal edges of set of the inner sleeve 14 radially outwardly projecting fins 16. Subsequently, the outer sleeve 12 is welded by means of a blind seam with the free end edges of the underlying fins 16 of the intermediate sleeve 18 to form the outer cells 20.

Now, the outer sleeve 12 is provided by both end faces 11 ago with the incisions 26 and at the ends thereof with the circular recesses 28.

Then, the outer sealing sleeves 24 are placed on the outer sleeve 12 and connected thereto. For this purpose, the outer sealing sleeve 24, whose inner diameter is matched to the outer diameter of the outer sleeve 12, coaxially placed in the axial direction y on the outer sleeve 12 and the circular recesses 28 at the ends of the incisions 26 superior free edge of the outer sealing sleeve 24 by means of two circumferential Welded seams 34, 36 joined to the outer sleeve 12.

The above-described joints are preferably designed as welding seams produced by means of a laser or electron beam, in particular with a laser beam. However, the joints can also be soldered. The cutting of the cuts 26 and the recesses 28 is also preferably carried out by means of a laser or electron beam, in particular with a laser beam.

One in the Fig. 9 and 15 shown cellular wheel 10 of a pressure wave supercharger, not shown in the drawing consists of a concentric with a rotation axis y of the cellular wheel 10 outer sleeve 12, a concentric with the outer sleeve 12 inner sleeve 14 and a between the outer sleeve 12 and the inner sleeve 14 concentrically arranged to these intermediate sleeve 18th The outer annular space between the intermediate sleeve 18 and the outer sleeve 12 and the inner annular space between the intermediate sleeve 18 and the inner sleeve 14 are divided by radially arranged to the rotation axis y strip-shaped fins 16 into a plurality outer cells 20 and a plurality of inner cells 22. The exemplified cellular wheel 10 with a diameter D and a length L of, for example, 100 mm each has 54 outer cells 20 and 36 inner cells 22. The outer sleeve 12, the intermediate sleeve 18, the inner sleeve 14 and the fins 16 have a uniform wall thickness of z. B. 0.4 mm and consist of a highly heat-resistant metallic material, for. Inconel 2.4856. The said parts have in the direction of the rotation axis y an equal length L corresponding to the length of the cellular wheel 10 and extend between two perpendicular to the axis of rotation y end faces 11 of the cellular wheel 10. In the region of the two end faces 11 are on the outer sleeve 12 circumferential outer sealing sleeves 24 arranged with a aligned with the end face 11 of the cellular wheel 10 sealing surface 32 of a sealing profile 30 of a labyrinth seal. The counter surfaces to the sealing surfaces 32 required for the labyrinth seal form the control surfaces of the exhaust gas and air housings which are opposite the end faces 11 of the cellular wheel 10 in a pressure wave supercharger.

In the in the Fig. 9 and 15 illustrated cellular wheel 10 is the inner sleeve 14 according to Fig. 10 directly connected to a drive shaft 13. The drive shaft 13 is arranged as a hollow shaft with two spaced-apart from a tubular end portion 46 radially protruding ring lands 38, 40 configured. End surfaces 42, 44 of the annular webs 38, 40 are concentric with the drive shaft 13 aligned inner sleeve 14, wherein only the drive side further away annular web 38 with the inner sleeve 14 z. B. is joined by means of a circumferential laser weld seam. The axis of rotation of the drive shaft 13 corresponds to the axis of rotation y of the inner sleeve 14 or of the cell wheel 10 placed on the drive shaft 13.

The tubular end part 46 of the drive shaft 13 is adjoined by a conical intermediate part 48, which merges into a substantially tubular shaft part 50 with a receptacle 52 for a coupling piece 54 to be connected to a motor drive. The coupling piece 54 has a coupling axis 56 with longitudinal ribs 58 which engage upon insertion of the coupling piece 54 into the receptacle 52 of the tubular shaft part 50 in corresponding longitudinal grooves 60 in the receptacle 52 ( Fig. 11 ).

How out Fig. 10 can be seen, are provided in the tubular end portion 46 of the drive shaft 13 between the two ring lands 38, 40 symmetrically about the circumference arranged first openings 62. In conical intermediate part 48, second openings 64 are also provided symmetrically over the conical peripheral surface. The openings 62, 64 serve to reduce weight and also have an air circulation with appropriate cooling effect.

The FIGS. 15 and 16 show a further embodiment of the cellular wheel 10. The cellular wheel 10, for example, on the drive shaft 13 after FIG. 2 or after FIG. 10 be used. As in the Fig. 15, 16 and 17 are shown, 18 incisions 26 are arranged in the intermediate sleeve 18 between joints 17 adjacent lamellae 16 with the intermediate sleeve. In these figures, this is the one embodiment in which the incisions 26 are arranged exclusively in the intermediate sleeve 18 and the outer sleeve 12 and the inner sleeve 14 have no cuts. The following description can also be applied to the embodiment described above with the incisions in the outer sleeve 12 and / or intermediate sleeve 18 and / or inner sleeve 14.

These cuts 26 in the intermediate sleeve 18 are parallel to the slats 16 and extend starting from each end face 11 of the cellular wheel 10 and the intermediate sleeve 18 over a length of z. B. 15 mm. The incisions 26 end in a circular recess 28 with a diameter of z. B. 2 mm.

The function of the cuts 26 will be described below with reference to FIGS. 18 and 19 and also the FIGS. 15 and 16 explained in more detail. FIGS. 18 and 19 schematically show a section in the direction of the rotation axis y seen. Fig. 19 represents the state of the FIGS. 15 and 16 in which the fins 16 and also parts of the intermediate sleeve 18 are deformed due to the temperature changes described below.

Under the operating conditions prevailing in a pressure wave supercharger, temperature changes occurring rapidly on both the hot gas side and the cold gas side occur in the interior of the cellular wheel 10 in a range from the end faces 11 to a depth of approximately 20 mm 200 to 300 ° C and lead in this area to periodically strongly fluctuating thermal expansions and thermal contraction of the fins 16 in the radial direction. These expansions or contraction represent an enormous burden on the material and experiments have shown that cracks occur in the region of the fins 16. The cracks extend either along the joints 17 or in the blade 16 itself, which can lead to a break in the blade 16.

Fig. 18 shows an operating state in which the cellular wheel 10 is in the axial direction over its entire length at a substantially constant operating temperature. Under these conditions, there is thus no difference in the thermal expansion of the lamellae 16 in the radial direction over the entire length of the cellular wheel 10.

Fig. 15, 16 and 19 show an operating state in which the fins 16 in a one of an end face 11 of the cellular wheel 10 to a depth of about 15 to 20 mm extending edge region of the cellular wheel 10 by 200 to 300 ° C higher temperature than in an inner region of the cell wheel 10. Under these conditions, the higher temperature of the fins 16 in the edge region in comparison to the fins in the interior of the cellular wheel 10 leads to a greater thermal expansion. By between joints 17 adjacent lamellae 16 with the intermediate sleeve 18th arranged incisions 26, the intermediate sleeve 18 in the edge region of the cellular wheel 10 in edge strips 18 a, 18 b divided so that adjacent edge strips 18 a, 18 b in the radial direction are mutually displaceable. As a result, each slat 16 a, 16 b, together with the edge strip 18 a, 18 b joined to it, expand from its original position in the intermediate sleeve 18 in the radial direction, without any tensile stresses in the slats due to temperature-induced, rapid load changes in rapid succession 16 themselves and in the region of their joints 17 with the outer and inner sleeves 12, 14 and dismantle and can lead to material damage. The in the Fig. 15, 16 and 19 shown operating state results from the rapid periodic temperature increases on the hot gas side of the cellular wheel 10. The arrangement of the incisions 26 thus a deformation of the fins 16 in the radial direction allows, which largely prevents the stresses in the region of the fins 16.

With reference to Fig. 16 Now the compensation of the temperature-induced expansion of the fins 16 is explained again. The lamella 16a is assigned to an edge strip 18a of the intermediate sleeve 18 formed by incisions 26 provided on the left and right of the lamella 16a. In other words, it can also be said that an edge strip 18 a protruding from the base body of the intermediate sleeve 18 is formed by the notches 26. The lamella 16a is firmly connected to the edge strip 18a via the joint 17. With an increase in temperature, the blade deformed 16a in the radial direction in the front region over the edge strip 18 a and this deformation can be compensated by a movement of the edge strip 18 a in the direction of the rotation axis y. In the lamella 16a itself there is no voltage or a greatly reduced voltage.

With respect to the lamella 16b, the explanations just given may be repeated, with the deformation taking place away from the axis of rotation y. The lamella 16b is in this case connected to an edge strip 18b, with deformation of the lamella 16b of the corresponding edge strip 18b deformed. The edge strip 18 b is provided by two left and right of the blade 16 b extending into the intermediate sleeve 18 cuts 26.

On the cold gas side results from the rapid temperature changes an operating condition, in which the fins 16 are in the edge region of the cellular wheel 10 in comparison to the fins in the interior of the cellular wheel 10 at a lower by 200 to 300 ° C temperature. Under these conditions, the lower temperature of the fins 16 in the edge region of the cellular wheel 10 leads to a stronger contraction in the radial direction in comparison to the fins inside the cellular wheel 10. Each slat 16 a, 16 b can thus together with the edge strip 18 a, 18 b contracted from its original position in the intermediate sleeve 18 in the radial direction, without causing temperature-induced, rapid load changes in rapid succession compressive stresses in the slats 16th in the region of their joints 17 with the outer and inner sleeves 12, 14 and dismantle and can lead to material damage.

The arrangement of the outer sealing sleeves 24 is made of the Fig. 12, 14th and 15 seen. The cylindrical outer sealing sleeves 24 have a width of z. B. 20 mm. At both end faces 11 of the cellular wheel 10 have in the FIGS. 20 to 22 illustrated outer sealing sleeves 24 a radially outwardly projecting sealing profile 30 with an aligned with the end face 11 of the cellular wheel 10 sealing surface 32 having a width d3 of z. B. 1.5 mm for a labyrinth seal. The outer sealing sleeve 24 is seated in a substantially remote from the end face 11 of the cellular wheel 10 area on the outer sleeve 12 and is joined in this area via a circumferential weld 34 with the outer sleeve 12. From the end face 11 of the cellular wheel 10 to the joining area with the outer sleeve 12, the outer sealing sleeve 24 with a wall thickness d1 of eg 0.25 mm has a thickness-reduced area 23 with a thickness d2 of, for example, 0.13 mm and thus a radial distance to the outer sleeve 12, so that from the end faces 11 of the cellular wheel 10 to the joining region of the outer sealing sleeve 24 with the outer sleeve 12 between the sealing sleeve 24 and outer sleeve 12, an open at the end faces 11 of the cellular wheel 10 annular gap 66 results. To stabilize the mutual position of sealing sleeve 24 and outer sleeve 12, the sealing sleeve 24 below the sealing profile 30 radially inwardly projecting lugs as a spacer 68 with a height d4 of, for example, 0.13 mm. For example, six spacers 68 are arranged distributed uniformly over the circumference of the sealing profile 30 of the sealing sleeve 24.

As in the Fig. 10, 12, 13, 14th and 17 are shown in the inner sleeve 14 in the FIGS. 23 to 25 shown first inner sealing sleeve 70 and a in the FIGS. 26 to 28 illustrated second inner sealing sleeve 72 is inserted. The first inner sealing sleeve 70 is arranged on the hot gas side, the second inner sealing sleeve 72 on the cold gas side of the cellular wheel 10.

At the end faces 11 of the cellular wheel 10, the inner sealing sleeves 70, 72 have a radially inwardly projecting sealing profile 74 in the form of an annular web with an aligned with the end face 11 of the cell wheel sealing surface 75 with a width of z. B. 1.5 mm. In an area extending from the end faces 11 of the cellular wheel 10 in the inner sleeve 14 of z. B. each 20 mm, the inner sealing sleeves 70, 72 have a reduced thickness region 73 and thus a radial distance from the inner sleeve 14 so that starting from the end faces 11 of the cellular wheel 10, starting between inner sealing sleeve 70, 72 and inner sleeve 14 at the end faces 11 of the cellular wheel 10 open annular gap 66 results. Subsequent to the annular gap 66, the inner sealing sleeves 70, 72 of the inner sleeve 14 are substantially form-fitting, extending to the respective closer annular web 38, 40 at the tubular end portion 46 of the drive shaft 13 and are connected to the corresponding annular web 38, 40 by means of a circumferential weld seam joined. The annular webs 38, 40 on the tubular end portion 46 of the drive shaft 13 are joined to the inner sleeve 14 by means of a circumferential weld. The sealing profile 74 is welded on the drive side of the farther end face 11 of the cellular wheel 10, ie on the hot gas side, with an inner sleeve 14 closing outer cover 78. Likewise, the annular web 38 further away from the drive side is welded to the tubular end part 46 of the drive shaft 13 with an inner cover 80 closing the inner sleeve 14 in the interior of the cellular wheel 10. To stabilize the mutual position of inner sealing sleeve 70, 72 and inner sleeve 14, the inner sealing sleeves 70, 72 on the outside over the sealing profile 74 radially outwardly projecting lugs as spacers 68 to the inner sleeve 14. For example, six spacers 68 are arranged uniformly distributed over the circumference of the inner sealing sleeve 70, 72. The above for the in the FIGS. 20 to 22 shown outer sealing sleeves 24 indicated values for the dimensions d1, d2, d3 and d4 also apply to those in the Fig. 23 to 28 shown inner sealing sleeves 70, 72nd

In particular from the Fig. 12, 14th and 17 as well as the Fig. 20 to 28 It can be seen that for generating the open at the end face 11 of the cellular wheel 10 annular gap 66 between the sealing sleeves 24, 70, 72 and the outer and inner sleeve 12, the inner diameter of the sealing sleeves 24, 70, 72 is increased at a constant outer diameter. This can be achieved with a material thinning by a massive forming, wherein the displaced from the annular gap area material for forming the sealing profile 30, 74 is used. To increase the annular gap width between the outer sealing sleeves 24 and the outer sleeve 12 is, as from the FIGS. 12 and 14 recognizable, in addition reduces the outer diameter of the outer sleeve 12 in the annular gap area at a constant inner diameter. Here, the wall thickness a1 of the outer sleeve 12 is for example 0.25 mm and the thickness a2 of the thickness-reduced portion 23, for example, 0.13 mm. In the same way, the annular gap width between inner sealing sleeves 70, 72 and the inner sleeve 14 can be increased by reducing the inner diameter of the inner sleeve 14 while the outer diameter remains the same, with the protrusions for the outer sleeve 12 for a1 and a2 also applying to the inner sleeve 14.

To produce the cellular wheel 10, the inner sleeve 14 is provided with the slats 16, which are positioned precisely with a longitudinal edge and project radially outwardly with the free longitudinal edge. Subsequently, the intermediate sleeve 18, whose inner diameter and length is matched to the outer diameter formed by the free longitudinal edges of the inner sleeve 14 radially outwardly projecting fins 16 and the length of the inner sleeve 14, with the previously attached with the intermediate sleeve 18 with a longitudinal edge positionally joined and set with the free longitudinal edge radially outwardly projecting fins 16 in the axial direction y coaxial and accurate position on the free longitudinal edges of the inner sleeve 14 radially outwardly projecting fins 16. The intermediate sleeve 18 is then welded by means of a blind seam with the free end edges of the underlying slats 16 of the inner sleeve 14 to form the inner cells 22. Subsequently, the intermediate sleeve 18 is provided from both end faces 11 forth with the incisions 26 and at the ends thereof with the circular recesses 28.

In a next step, the outer sleeve 12, whose inner diameter and length is matched to the outer diameter formed by the free longitudinal edges of the radially outwardly projecting from the intermediate sleeve 18 lamella 16 and the length of the intermediate sleeve 18, in the axial direction y coaxial with the free longitudinal edges of of the Intermediate sleeve 14 set radially outwardly projecting fins 16. Then, the outer sleeve 12 is welded by means of a blind seam with a laser beam with the free end edges of the underlying slats 16 of the intermediate sleeve 18 to form the outer cells 20.

In a further step, the outer sealing sleeves 24, whose inner diameter is matched to the outer diameter of the outer sleeve 12, are coaxially placed in the axial direction y on the outer sleeve 12 and joined with this. Likewise, the inner sealing sleeves 70, 72, whose outer diameter is matched to the inner diameter of the inner sleeve 14, coaxially inserted in the axial direction y on the inner sleeve 14 and joined with this and with the annular webs 38, 40 at the tubular end portion 46 of the drive shaft 13. Subsequently, the inner and the outer cover 80, 78 are inserted and joined with the annular web 38 on the tubular end portion 46 and with the annular web 74 on the hot gas side sealing sleeve 70.

The above-described joints are preferably designed as welding seams produced by means of a laser or electron beam, in particular with a laser beam. However, the joints can also be soldered. The cutting of the cuts 26 and the recesses 28 is also preferably carried out by means of a laser or electron beam, in particular with a laser beam, wherein a minimum cutting width of about 15 microns is achieved.

LIST OF REFERENCE NUMBERS

10

feeder

11

faces

12

outer sleeve

13

drive shaft

14

inner sleeve

15

flanged

16

lamella

17

Joints 16/12, 16/14

18

intermediate sleeve

19

Thickening at 16

20

outer cells

22

inner cells

23

reduced thickness range

24

outer sealing sleeve

25

Border edge of 24

26

Cuts in 12, 14, 18

28

recess

30

sealing profile

32

Sealing surface at 30

34, 36

Joints 24/12

38.40

ring lands

42, 44

end surfaces

46

tubular end part

48

conical intermediate part

50

tubular shaft part

52

admission

54

coupling

56

coupling axis

58

longitudinal ribs

60

longitudinal grooves

62

first openings

64

second openings

66

annular gap

68

Noses / spacers

70

first inner sealing sleeve

72

second inner sealing sleeve

73

reduced thickness range

74

sealing profile

75

Sealing surface of 74

76

recess

77

Border edge of 70, 72

78

outer lid

80

inner lid

y

axis of rotation

a1

Thickness of 12, 14, 18

a2

Thickness of 23

d1

Thickness of 24, 70, 72

d2

Thickness of 73

d3

Thickness of 74

d4

Thickness of 68

e

Length of 26

f

Diameter of 28

G

Width of 24

H

Width of 32

m

Excess of 24

Claims (17)

Cellular wheel made of metal, having an outer sleeve (12) lying coaxially to a rotation axis (y), an inner sleeve (14) lying coaxially with the outer sleeve (12), at least one intermediate sleeve arranged coaxially with said outer sleeve (12) and inner sleeve (14). 18) arranged between successive sleeves (12, 18, 18, 14), substantially radially to the rotation axis (y) aligned with adjacent sleeves (12, 18, 18, 14) joined lamellae (16), with the outer sleeve (12 ) and with the outer sleeve (12) joined outer sealing sleeves (24) having a sealing profile (30) for a labyrinth seal, and with a in the rotation axis (y) lying drive shaft (13), characterized in that
at least the outer sleeve (12), the inner sleeve (14) and / or the intermediate sleeve (18) or at least one of the intermediate sleeves (18) from both end faces (11) of the cellular wheel (10) outgoing incisions (26) between adjacent blades (16 ), or
that only the intermediate sleeve (18) or at least one of the intermediate sleeves (18) of the two end faces (11) of the cellular wheel (10) outgoing incisions (26). Cell wheel according to claim 1, characterized in that the incisions (26) in recesses (28) end and / or that two adjacent incisions (26) one of the corresponding sleeve (12, 14, 18) associated edge strips (18 a, 18 b ), wherein a single edge strip is assigned in each case a single lamella (16) and wherein the recesses (28) preferably have an extension (f) of 1 to 2 mm. Cell wheel according to claim 1 or 2, characterized in that the inner sleeve (14) on a coaxially arranged to this, with the drive shaft (13) joined flange sleeve (15) sits and the outer sleeve (12) of both end faces (11) of the cellular wheel ( 10) has outgoing incisions (26) between adjacent lamellas (16), one of the end faces (11) of the cellular wheel (10) removed lying outer edge (25) of the outer sealing sleeves (24) the incisions (26) surmounted by a Mass (m) and the outer sealing sleeves (24) only in the incisions (26) projecting area with the outer sleeve (12) are joined. Cell wheel according to claim 3, characterized in that the sealing profile (30) of the outer sealing sleeves (24) has a sealing surface (32) aligned with the end faces (11) of the cellular wheel (10) and the sealing sleeves (24) with the outer sleeve (12). form an annular gap (66) open at the end faces (11) of the cellular wheel (10). Cell wheel according to claim 3 or 4, characterized in that the inner sleeve (14) of both end faces (11) of the cellular wheel (10) outgoing incisions (26) between adjacent lamellae (16) and the inner sleeve (14) with the flange sleeve (15 ) is joined between adjacent lamellas (16) between opposed incisions (26). Cell wheel according to claim 1, characterized in that the inner sleeve (14) is joined to the drive shaft (13) and the intermediate sleeve (18) of both end faces (11) of the cellular wheel (10) outgoing incisions (26) between adjacent blades ( 16). A cellular wheel according to claim 6, characterized in that the sealing profile (30) of the outer sealing sleeves (24) has a sealing surface (32) aligned with the end faces (11) of the cellular wheel (10) and in the inner sleeve (14) with the inner sleeve (14 ) fitted inner sealing sleeves (70, 72) with a sealing profile (74) with a with the end faces (11) of the cellular wheel (10) aligned sealing surface (75) are arranged for a labyrinth seal. Cell wheel according to claim 7, characterized in that the sealing sleeves (24, 70, 72) only in the region of the end faces (11) of the cellular wheel (10) remote end with the outer or inner sleeve (12, 14) are joined and with the outer and inner sleeves (12, 14) on the end faces (11) of the cellular wheel (10) open annular gap (66). Cell wheel according to claim 4 or 8, characterized in that the volume of the annular gap (66) by a in the region of the annular gap (66) reduced wall thickness (d2) of the sealing sleeves (24, 70, 72) is increased; or that the volume of the annular gap (66) is increased by a reduced wall thickness (a2) of the outer or inner sleeve (12, 14) in the region of the annular gap (66). Cell wheel according to one of claims 8 or 9, characterized in that in order to stabilize the annular gap (66) from the side facing the outer or inner sleeve (12, 14) side of the sealing sleeves (24, 70, 72) in the region of the end faces (11 ) of the cellular wheel (10) over the circumference of the sealing sleeves (24, 70, 72) arranged distributed spacer elements (68) protrude. Cell wheel according to one of claims 8 to 10, characterized in that for stabilizing the annular gap (66) from the sealing sleeve (24, 70, 72) facing side of the outer and inner sleeve (12, 14) in the region of the end surfaces (11 ) of the cellular wheel (10) over the circumference of the outer and inner sleeves (12, 14) distributed spaced spacer elements (68) protrude. Cell wheel according to one of claims 1 to 11, characterized in that the length (e) of the incisions (26) is 10% to 30% of the length (L) of the cellular wheel (10); and / or that the outer sleeve (12), the inner sleeve (14), the Zwischenhülse / n (18), the fins (16) and the sealing sleeves (24, 70, 72) made of sheet metal with a thickness of less than 0.5 mm are made. Cell wheel according to claim 6, characterized in that the drive shaft (13) has two coaxial with the drive shaft (13) arranged and spaced apart annular webs (38, 40) having a peripheral surface (42, 44) as bearing surfaces for the inner sleeve (14) and at least one of the annular webs (38, 40) is joined to the inner sleeve (14). A cellular wheel according to claim 13, characterized in that the end remote from the end faces (11) of the cellular wheel (10) of the inner Sealing sleeves (70, 72) with one of the annular webs (38, 40) is joined and / or that an inner sealing sleeve (70) on an end face (11) of the cellular wheel (10) with a lid (78) is joined and / or a ring land (38) is joined to a lid (78). Cellular wheel according to one of claims 13 or 14, characterized in that the drive shaft (13) as a hollow shaft with a tubular end portion (46), a conical intermediate part (48) and a tubular shaft portion (50) with a receptacle (52) for a with a motor drive to be connected coupling piece (54) is configured. A cellular wheel according to claim 18, characterized in that the tubular end portion (46) and the conical intermediate portion (48) have symmetrically circumferentially disposed openings (62, 64), and / or that the coupling portion (54) has a coupling axis (56) Longitudinal ribs (58) which engage during insertion of the coupling piece (54) in the receptacle (52) of the tubular shaft part (50) in longitudinal grooves (60) in the receptacle (52). Use of a cellular wheel (10) according to one of the preceding claims in a pressure wave supercharger for supercharging internal combustion engines, in particular gasoline engines.

Images