Radial compressor for a charging device of an internal combustion engine, charging device and lamellas for an iris diaphragm mechanism, and method for producing such lamella

Abstract

A radial compressor has an iris diaphragm mechanism for a pressure-charging device of an internal combustion engine. The radial compressor has a bearing assembly, in which a rotor shaft is rotatably mounted, having a compressor impeller arranged in a compressor housing for conjoint rotation on the rotor shaft and having a fresh air supply channel for carrying a fresh air mass flow to the compressor impeller. The iris diaphragm mechanism is upstream of the compressor impeller, allowing variable adjustment of a flow cross section for the fresh air mass flow for admission to the compressor impeller, at least over a partial region. For this purpose, the iris diaphragm mechanism has multiple lamellae which each have a plate style lamella main body and a pin style actuating element as integral constituent parts of the respective lamella.

Claims

1. A method for producing a lamella comprising: providing a plate style lamella semi-finished part composed of sheet metal, which has a lamella main body with an outer edge and a bearing element for the rotatable mounting of the lamella, wherein a protuberance is formed which projects beyond the edge; and bending the projecting protuberance relative to the lamella main body such that the protuberance extends perpendicular to a main extent plane defined by the lamella main body, and thus an actuating element is formed as an integral constituent part of the lamella.

2. The method for producing a lamella as claimed in claim 1, wherein the protuberance projecting beyond the edge has a central piece with two oppositely situated limbs projecting from the central piece, and wherein the bending of the projecting protuberance relative to the lamella main body such that the protuberance extends perpendicular to a main extent plane defined by the lamella main body is followed by the bending of the projecting limb such that an actuating element in the form of a slotted cylinder is formed as an integral constituent part of the lamella.

3. A lamella for an iris diaphragm mechanism of a radial compressor, wherein the lamella has a plate style lamella main body, a bearing element for the rotatable mounting of the lamella, and a pin style actuating element for actuating the respective lamella, the main body and the actuating element are integral parts of the lamella, wherein the actuating element of the lamella is formed from a protuberance on the lamella main body to extend perpendicularly with respect to a main extent plane defined by the lamella main body, and wherein the lamella main body is formed from sheet metal, and the actuating element is manufactured by bending of the protuberance.

4. A radial compressor for a supercharging device of an internal combustion engine comprising: a rotor shaft rotatably mounted in a bearing assembly; a compressor impeller arranged in a compressor housing for conjoint rotation on the rotor shaft; an air supply channel for carrying an air mass flow to the compressor impeller; an iris diaphragm mechanism to at least partially close and open a diaphragm aperture allowing variable adjustment of a flow cross section for the air mass flow for admission to the compressor impeller, at least over a partial region of the cross section; and a plurality of lamellae respectively rotatable about a center of rotation and each having a lamella main body and an actuating element for actuating the respective lamella, wherein the main body and the actuating element are integral to the respective lamella, wherein the actuating element of at least one lamella is formed from a protuberance on the lamella main body to extend perpendicularly with respect to a main extent plane defined by the lamella main body, and wherein the lamella main body is formed from sheet metal, and the actuating element is manufactured by bending of the protuberance.

5. The radial compressor as claimed in claim 4, wherein the protuberance is formed to project beyond an outer edge of the lamella main body such that the actuating element is arranged at the outer edge of the lamella main body.

6. The radial compressor as claimed in claim 4, wherein the protuberance is formed to project beyond an outer edge of the lamella main body such that the actuating element is arranged outside the lamella main body and spaced apart from the outer edge of the lamella main body.

7. The radial compressor as claimed in claim 4, wherein the projecting protuberance body is formed such that the actuating element has a shape of a slotted cylinder which extends perpendicular to the main extent plane.

8. The radial compressor as claimed in claim 4, wherein the actuating element is formed from the lamella main body by deep drawing sheet metal.

9. The radial compressor as claimed in claim 4, further comprising a bearing element in an end region of the lamella situated opposite the actuating element, wherein the lamella is rotatably mounted to a bearing ring of the iris diaphragm mechanism with the bearing element.

10. The radial compressor as claimed in claim 9, wherein the bearing element is a bore mountable on a bearing pin fixed in the bearing ring.

11. The radial compressor as claimed in claim 9, wherein the bearing element is a pin element that extends perpendicular to a main extent plane defined by the lamella main body in an opposite direction in relation to the actuating element and mountable on a bore defined by the bearing ring.

12. The radial compressor as claimed in claim 4, wherein the iris diaphragm mechanism has a fixed bearing ring and an adjusting ring arranged concentrically thereto and rotatable about a common axis, wherein each lamella is mounted rotatably about its center on the bearing ring.

13. The radial compressor as claimed in claim 12, further comprising a groove defined by the adjusting ring and corresponding to each lamella, wherein the groove runs obliquely in relation to the radial direction of the adjusting ring such that the actuating element of the respective lamella is guided for actuation.

14. The radial compressor as claimed in claim 4, wherein the actuating element is a pin style actuating element.

15. The radial compressor as claimed in claim 4, wherein the radial compressor is located in a supercharging device which is one of: an exhaust-gas turbocharger, a supercharger operated by electric motor, and as a supercharger operated via a mechanical coupling to the internal combustion engine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:

(2) FIG. 1 shows a simplified schematic sectional view of a turbocharger according to prior art, as an example of a conventional supercharging device for an internal combustion engine;

(3) FIG. 2 shows a simplified schematic sectional view of a supercharging device with a radial compressor according to the invention;

(4) FIGS. 3a to 3c show schematic plan views of an iris diaphragm mechanism in three different operating states according to an exemplary embodiment;

(5) FIGS. 4a and 4b show a lamella of the iris diaphragm mechanism in different production states according to an exemplary embodiment, in each case in a plan view and a perspective view;

(6) FIG. 5a shows a schematic plan view of an embodiment of an adjusting ring of the iris diaphragm mechanism;

(7) FIG. 5b shows a schematic plan view of an embodiment of a bearing ring of the iris diaphragm mechanism;

(8) FIGS. 6a to 6c show a lamella of the iris diaphragm mechanism in different production states according to a further exemplary embodiment, in each case in a plan view and a perspective view;

(9) FIGS. 7a to 7c show a lamella of the iris diaphragm mechanism in different production states according to a further exemplary embodiment, in each case in a plan view and a perspective view;

(10) FIG. 8a shows a lamella of the iris diaphragm mechanism according to a further exemplary embodiment, in each case in a plan view and a perspective view;

(11) FIG. 8b shows a further embodiment of a lamella of the iris diaphragm mechanism, in each case in a plan view and a perspective view; and

(12) FIG. 9 shows a simplified schematic flow diagram of a method for producing a lamella.

DETAILED DESCRIPTION

(13) The exemplary embodiments will be described below with the aid of the appended figures. Identical elements or elements of identical action are denoted by the same reference designations throughout the figures.

(14) FIG. 1 schematically shows a supercharging device for an internal combustion engine, based on the example of an exhaust-gas turbocharger 1a according to the conventional prior art, in a sectional illustration, which exhaust-gas turbocharger comprises an exhaust-gas turbine 20, a radial compressor 30 and a rotor bearing 40. The exhaust-gas turbine 20 is equipped with a wastegate valve 29 and an exhaust-gas mass flow AM is indicated by arrows. The radial compressor 30 has an overrun air recirculation valve 39 and an air mass flow LM is likewise indicated by arrows.

(15) A so-called turbocharger rotor 10 of the exhaust-gas turbocharger 1a has a turbine impeller 12, a compressor impeller 13 and a rotor shaft 14 (also referred to simply as shaft). The turbocharger rotor 10 rotates about a rotor axis of rotation 15 of the rotor shaft 14 during operation. The rotor axis of rotation 15 and at the same time the turbocharger axis 2 (also referred to as longitudinal axis) are illustrated by the indicated centerline and identify the axial orientation of the exhaust-gas turbocharger. The turbocharger rotor 10 is supported with its rotor shaft 14 by means of two radial bearings 42 and one axial bearing disk 43. Both the radial bearings 42 and the axial bearing disk 43 are supplied with lubricant via oil supply channels 44 of an oil connection 45.

(16) In general, a conventional exhaust-gas turbocharger 1a, as illustrated in FIG. 1, has a multi-part construction. Here, a turbine housing 21, which is arrangeable in the exhaust tract of the internal combustion engine, a compressor housing 31, which is arrangeable in the intake tract of the internal combustion engine, and a bearing housing 41 between the turbine housing 21 and compressor housing 31 are arranged adjacent to one another with respect to the common turbocharger axis 2 and are connected to one another in terms of assembly.

(17) A further structural unit of the exhaust-gas turbocharger 1a is constituted by the turbocharger rotor 10, which has the rotor shaft 14, the turbine impeller 12, which is arranged in the turbine housing 21 and which has an impeller blade arrangement 121, and the compressor impeller 13, which is arranged in the compressor housing 31 and which has an impeller blade arrangement 131. The turbine impeller 12 and the compressor impeller 13 are arranged on the opposite ends of the common rotor shaft 14 and connected rotationally conjointly thereto. The rotor shaft 14 extends in the direction of the turbocharger axis 2 axially through the bearing housing 41 and is mounted in the axial and radial directions therein so as to be rotatable about its longitudinal axis, the rotor axis of rotation 15, wherein the rotor axis of rotation 15 lies on the turbocharger axis 2, that is to say coincides therewith.

(18) The compressor housing 31 has an air supply channel 36, which has an intake pipe connector piece 37 for connection to the air intake system (not illustrated) of the internal combustion engine and which runs in the direction of the turbocharger axis 2 toward the axial end of the compressor impeller 13. Via this air supply channel 36, the air mass flow LM is drawn in from the air intake system by the compressor impeller 13. The air supply channel 36 may also be part of an intake connector and thus not part of the compressor housing 31.

(19) Furthermore, the compressor housing 31 generally has a spiral channel 32 which is arranged in a ring around the turbocharger axis 2 and the compressor impeller 13 and which widens spirally away from the compressor impeller 13, and which is also referred to as a so-called fresh-air flute. The spiral channel 32 has a gap opening which runs at least over a part of the inner circumference and which has a defined gap width, the so-called diffuser 35, which, directed in a radial direction away from the outer circumference of the compressor impeller 13, runs into the spiral channel 32 and through which the air mass flow LM flows away from the compressor impeller 13 at elevated pressure into the spiral channel 32. The spiral channel 32 furthermore has a tangentially outwardly directed air discharge channel 33 with a manifold connector piece 34 for connection to an air manifold (not illustrated) of an internal combustion engine. Through the air discharge channel 33, the air mass flow LM is conducted at elevated pressure into the air manifold of the internal combustion engine.

(20) FIG. 2 shows an embodiment of a supercharging device 1. The supercharging device 1 has an embodiment of a radial compressor 30, a rotor bearing and a drive unit 70. The radial compressor 30 has a compressor impeller 13 which is arranged in a compressor housing 31 and which is arranged rotationally conjointly on a rotor shaft 14 which is mounted rotatably in a bearing housing 41 of a rotor bearing 40.

(21) Furthermore, the radial compressor 30 has an air supply channel 36 which adjoins the compressor housing 31 and which forms the compressor inlet 36a and which serves for conducting an air mass flow LM onto the compressor impeller 13, and a spiral channel 32 which is arranged radially around the compressor impeller 13 in the compressor housing 31. Here, the spiral channel 32 serves to receive and discharge the compressed air mass flow LM flowing away from the compressor impeller 13 and exiting through the diffuser 35. Here, the iris diaphragm mechanism 50 is fixed in the air supply channel 36 of the compressor housing 31 and/or forms a partial region of the air supply channel 36 directly upstream of the compressor inlet 36a of the compressor housing 31.

(22) Upstream of the compressor impeller 13 in the air mass flow LM, the iris diaphragm mechanism 50 is, in addition to or as an alternative to an overrun air recirculation valve 39 (see FIG. 1), arranged in the air supply channel 36 immediately upstream of the compressor inlet 36a and forms a sub-region of the air supply channel 36 immediately upstream of the compressor inlet 36a of the compressor housing 31. The iris diaphragm mechanism 50 is designed to at least partially close or open a diaphragm aperture 55 such that a flow cross section for the air mass flow LM for admission into the compressor impeller 13 can be set variably at least over a partial region of the flow cross section.

(23) The iris diaphragm mechanism 50 has a bearing ring 68 which is fixed in the air supply channel 36 concentrically with respect to the compressor inlet 36a, an adjusting ring 53 which is arranged concentrically with respect to the bearing ring and which is rotatable about a common center and which has an adjusting lever 53a, and multiple lamellae 52 which are mounted so as to be rotatable about a respective center of rotation in the bearing ring 68. The lamellae 52 have in each case one plate style lamella main body 56 and a pin style actuating element (not visible here), which is designed for actuating the respective lamella 52, as integral constituent parts of the respective lamella 52.

(24) The drive unit 70 is not shown in any more detail in FIG. 2 and may be embodied either as an exhaust-gas turbine or as an electromotive drive unit, or else as a mechanical coupling to the internal combustion engine, for example as an intermediate gear mechanism which is operatively connected to a rotating shaft of the internal combustion engine, making the supercharging device 1 in one case into an exhaust-gas turbocharger 1a, and in the other case into an electromotively operated supercharger, also referred to as an E-booster or E-compressor, or into a mechanical supercharger.

(25) FIGS. 3a to 3c show schematically an embodiment of an iris diaphragm mechanism 50 for a radial compressor 30 according to the invention in three different operating states. The iris diaphragm mechanism 50 has a stationary, fixed (positionally fixed) bearing ring 68 (not illustrated). As illustrated in FIG. 5b, the bearing ring 68 may be formed by a separate component which is fixed in the surrounding housing, for example of the air supply channel 36. As an alternative, the bearing ring may also be formed directly in the surrounding housing and integrally with the latter. Thus, the bearing ring 68 may also be formed directly at the compressor inlet 36a of the compressor housing 31. As an alternative, it is also possible for a separate housing to be provided for the iris diaphragm mechanism 50, such that the iris diaphragm mechanism 50 can be mounted as a separate, pre-assembled functional unit on the compressor housing 31 or in the air supply channel 36.

(26) In this example, three lamellae 52 are mounted on the bearing ring 68 so as to be rotatable about a respective bearing element 67. For this purpose, the bearing ring 68 has an associated rotary bearing location 69 for each lamella 52 (see FIG. 5b), at which bearing location the respective lamella 52 is rotatably mounted by means of its bearing element 67.

(27) Each lamella 52 has an actuating element (not visible in FIGS. 3a, 3b and 3c) for actuation by an adjusting ring 53, wherein the bearing element 67 is arranged in an end region of the respective lamella 52 situated opposite the actuating element.

(28) As a bearing element 67, it is for example possible for a bore to be provided in the respective lamella 52, by means of which bore the respective lamella 52 is mounted on a bearing pin 69a, visible in FIG. 5b, which is fixed in the bearing ring 68 and which forms the rotary bearing location.

(29) The iris diaphragm mechanism 50 furthermore has an adjusting ring 53, which is arranged concentrically with respect to the bearing ring 68 and which can be rotated about the common center, the adjusting ring, in FIG. 3a, being largely concealed by the lamellae 52 and being visible only by its adjusting lever 53a. An embodiment of the adjusting ring 53 is illustrated separately in FIG. 5a.

(30) In the example in FIGS. 3a to 3c and 5a, the adjusting ring 53 has three grooves 54 (only shown indicatively in FIGS. 3a to 3c) for guided actuation of the lamellae 52. In this case, for each lamella 52, there is provided in each case one groove 54 which extends obliquely in relation to the radial direction of the adjusting ring 53 and into which the actuating element of the respective lamella 52 engages and in which the actuating element is guided.

(31) In this way, the lamellae 52 are moved in a synchronized manner by rotation of the adjusting ring 53. The adjusting ring 53 is mounted at its outer circumference, for example, on or in the housing of the iris diaphragm mechanism 50, or in a housing part formed for this purpose in the compressor housing 31 or the air supply channel 36.

(32) By actuation of the adjusting ring 53, that is to say by rotation about the center shared with the bearing ring 68, the actuating elements of the lamellae 52 are guided radially inward by the obliquely extending grooves 54 and, in this way, the lamellae 52 are pivoted about the respective bearing location 67 likewise radially inward, and thus constrict a diaphragm aperture 55 of the iris diaphragm mechanism 50. Here, FIG. 3a shows the diaphragm aperture 55 with a maximum opening width, FIG. 3b shows the diaphragm aperture 55 with a reduced opening width, and FIG. 3c shows the diaphragm aperture 55 with a minimum opening width. These illustrations thus show the partial region of the flow cross section for this exemplary embodiment which can be adjusted variably by partial closure or opening of the iris diaphragm mechanism 50. The iris diaphragm mechanism 50 thus acts as a variable inlet throttle and, in this way, as mentioned at the outset, allows shifting of the characteristic map for the radial compressor 30.

(33) Lamellae 52 of various exemplary embodiments will be described below with reference to FIGS. 4a, 4b, 6a to 6c and 7a to 7c, the production of which lamellae will be discussed on the basis of the flow diagram illustrated in FIG. 9.

(34) FIGS. 4a and 4b show a lamella 52 for the iris diaphragm mechanism 50 according to an exemplary embodiment, in each case in a plan view and perspective view, in two production states, wherein FIG. 4a illustrates a lamella semi-finished part 52′, from which the final lamella 52 as illustrated in FIG. 4b is produced.

(35) In a first step S1, the lamella semi-finished part 52′ is provided. The lamella semi-finished part 52′ is formed as a single piece, for example by virtue of the corresponding shape being punched out of a planar metal sheet.

(36) The lamella semi-finished part 52′ and the finished lamella 52 have a lamella main body 56. The lamella main body 56 is of plate style form and is delimited by an outer edge 57. The outer edge 57 represents an outer main contour of the lamella main body 56, which in this case is interrupted by two incisions 58. A projecting protuberance 59 is formed between the two incisions. The lamella main body 56 defines a lamella main surface 60 which—with the exception of the incisions 58—is formed by the outer edge 57 and an imaginary continuous connecting line 57′ of the outer edge 57 in the region of the projecting protuberance 59 (see the dashed line in FIG. 4a). In other words, the main body defines a substantially closed shape which is defined by the main, outer edge 57 and which is theoretically closed in the region of interruptions such as the projecting protuberance 59. The projecting protuberance 59 initially lies in the same plane as the lamella main body 56, i.e. the main extent plane of the lamella main body, projects outward beyond the lamella main surface 60, and thus forms a projecting region 59. The projecting protuberance 59 represents an actuating element blank.

(37) In a subsequent second step S2, the projecting protuberance 59 is then bent relative to the lamella main body 56 such that the projecting protuberance 59 projects at least predominantly in a normal direction of the lamella main body 56, i.e. substantially perpendicularly from the latter. A final, pin style actuating element 61 is thus formed. The above-stated incisions 58 serve here as cutaway portions in the deformation region of the actuating element 61, which ensure that, during the bending of the projecting protuberance 59, the outer edge 57 of the lamella 52 remains free from deformation.

(38) As already mentioned, in the installed state of the iris diaphragm mechanism, the respective lamella 52 engages with its actuating element 61 into a groove, respectively provided for the purpose, in the adjusting ring 53, in order, when the adjusting ring 53 is correspondingly rotated, to pivot the respective lamella 52 about its center of rotation. Here, the center of rotation is formed by the respective associated rotary bearing location 69 in the bearing ring 68 or, for example, directly in the surrounding stationary housing of the iris diaphragm mechanism, on which the lamella 52 is rotatably mounted by means of a bearing element 67 formed on the lamella 52. The lamella 52 illustrated in FIGS. 4a and 4b has, for the rotational mounting, a bearing element 67, which in this exemplary embodiment is formed as a simple passage bore extending perpendicularly with respect to the main extent plane of the lamella main body 56 and is arranged in an end region of the lamella 52 situated opposite the actuating element 61. In this case, the rotary bearing location 69 is formed by a respective bearing pin 69a which is fixed in the bearing ring 68 (in this regard, see FIG. 5b) and on which the respective lamella 52 is fitted by way of its passage bore and is thus mounted.

(39) As can be seen in particular in the plan view as per FIG. 4b, the actuating element 61 is arranged so as to terminate flush with the outer edge 57 of the lamella main body 56. In other words, the actuating element 61 does not project beyond the lamella main surface 60.

(40) The lamella 52 makes it possible to realize the advantages and functions stated in the introduction. Owing to the positioning of the actuating element 61 at the edge of the lamella main body 56 and thus at the edge of the lamella 52, it is possible for the grooves 54 which are provided in the adjusting ring 53 and which serve for receiving the actuating element 61 to be kept closed in a radially inward direction, that is to say toward the center of the diaphragm aperture 55. This can be seen in detail in FIG. 5a, which shows an embodiment of the adjusting ring 53. The gap formed by the respective groove 54 thus remains closed toward the diaphragm aperture 55, whereby possible leakage by the iris diaphragm mechanism is kept low.

(41) FIGS. 6a to 6c show the production of a lamella 52 according to a further exemplary embodiment in three steps S1 to S3 (see FIG. 9), in each case in a plan view and a perspective view, wherein the explanations above apply substantially analogously. Here, with regard to the projecting protuberance, in addition to the single bending described in FIGS. 4a and 4b, a further bending method step is implemented, the result of which is illustrated in FIG. 6c. FIG. 6a shows a first lamella semifinished part 52′, which, analogously to that above, has a lamella main body 56 which has an outer edge 57 with two incisions 58. Formed between the incisions 58 is a projecting protuberance 59 which has a central piece 62, from which, by contrast to the embodiment mentioned above, two limbs 63 project to opposite sides. In a first method step S1, the blank is provided as above, which may be realized for example by punching out of a metal sheet in a punching process.

(42) Subsequently, in a second step S2 (see FIG. 9), again analogously to the embodiment shown in FIGS. 4a, 4b, a 90° bend of the projecting protuberance 59 is implemented, wherein the central piece 62 of the projecting protuberance 59 is correspondingly bent. In this way, a second lamella semi-finished part 52″ is formed.

(43) Then, in a further method step S3 (as illustrated by dashed lines in the method diagram in FIG. 9), the two limbs 63 are bent such that an actuating element 61a in the form of a slotted cylinder is formed, as can be seen in FIG. 6c.

(44) Analogously to the exemplary embodiment shown in FIGS. 4a, 4b, the actuating element 61a is, as per FIG. 6c, arranged and bent such that it in turn terminates flush with the outer edge 57 of the lamella main body 56, that is to say is arranged within the lamella main surface 60 and extends substantially perpendicular to the main extent plane defined by the lamella main body 56.

(45) FIGS. 7a to 7c show a further embodiment of a lamella 52 in three production steps. This embodiment of the lamella 52 differs from the exemplary embodiments of the lamella 52 shown above in FIGS. 4a and 4b and 6a to 6c substantially in that the actuating element 61a, which corresponds to the abovementioned slotted cylinder, is arranged outside the lamella main body 56, that is to say outside the lamella main surface 60. In other words, the actuating element 61a is, in this embodiment, arranged spaced apart from the outer edge 57 and outside the lamella main body 56. For the arrangement of the actuating element outside the lamella main body 56, it is not necessary for the actuating element to have the shape of a slotted cylinder. A simple design of the actuating element 61 as shown in the exemplary embodiment of FIGS. 4a, 4b can also be arranged outside the lamella main body 56.

(46) FIG. 8a shows a further embodiment of a lamella 52 according to the invention in a plan view and a perspective view. This embodiment is distinguished by the fact that, as a bearing element, a pin element 67a is provided on the respective lamella 52, which pin element is designed in the manner of an actuating element 61, as illustrated for example in FIGS. 4a, 4b. Alternatively, it is self-evidently also possible for an embodiment of the bearing element 67a in the form of an actuating element 61a according to the embodiments of FIGS. 6a to 6c or 7a to 7c to be provided. The bearing element 67a extends substantially perpendicularly with respect to a main extent plane defined by the lamella main body 56, in an opposite direction in relation to the actuating element 61. By means of the corresponding bearing element 67a, the respective lamella 52 is mounted rotatably about its center of rotation in a rotary bearing location 69, wherein the rotary bearing location 69 may be designed for example as a simple bore in the bearing ring 68. Here, the bearing ring 68 may be designed as a separate component or may also be formed directly in the surrounding housing.

(47) FIG. 8b shows a further embodiment of a lamella 52 according to the invention in a plan view and a perspective view. In this embodiment of the lamella 52, the lamella main body 56 is formed from a metal sheet, wherein the actuating element 61b is formed from the lamella main body 56 by deep drawing and extends substantially perpendicularly with respect to a main extent plane defined by the lamella main body 56. Furthermore, the illustrated lamella 52 has a bearing element 67b which, like the actuating element 61b, is also formed from the lamella main body 56 by deep drawing. Thus, this embodiment of the lamella 52 with the actuating element 61b and the bearing element 67b is also formed as a single piece and makes it possible to realize the advantages and functions stated in the introduction.

(48) It is furthermore pointed out that, in a respective lamella 52, it is also possible to select a combination of actuating element 61, 61a, 61b and bearing element 67, 67a, 67b of the above embodiments which is not explicitly illustrated in the figures. For example, in a lamella 52, a deep-drawn bearing element 67b may be combined with an actuating element 61a in the form of a slotted cylinder.

(49) The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the scope of the following claims.