Axial fluid bearing point and method for mounting two axial foil bearing arrangements

Abstract

The invention relates to an axial fluid bearing point (24) with two axial foil bearing arrangements, each comprising at least one bearing foil (26), which are radially assigned within a housing circumferential surface of a receiving space to two axially opposite housing end faces of two housing bodies. To optimize the axial fluid bearing point (24), the axial foil bearing arrangements are held at an axial distance from each other by means of at least one guide and / or retaining geometry provided on a cover foil of the respective axial foil bearing arrangement.

Description

[0001] The invention relates to an axial fluid bearing point with two axial foil bearing assemblies, each comprising at least one bearing foil, which are radially arranged within a housing circumferential surface of a receiving space and assigned to two axially opposite housing end faces of two housing bodies. The invention further relates to a method for mounting two axial foil bearing assemblies at such an axial fluid bearing point. State of the art

[0002] DE202022102710 U1 relates to a compressor comprising a compressor wheel, a shaft to which the compressor wheel is attached, an electric motor for driving the shaft, and an axial air bearing with a spring plate and a cover plate attached to a support. The spring plate and the cover plate are attached to the support with clips.

[0003] DE 112012002901 T1 relates to an air supply device for a fuel cell comprising a shaft, a compressor wheel arranged in a compressor housing and attached to one end of the shaft, a bearing arranged in a bearing housing for supporting the shaft, and an electric motor for driving the shaft, which is arranged in the bearing housing. The shaft has two bearing sections designed as separate components, a magnet section arranged between the bearing sections, which forms a separate component, and a magnet section forming the rotor of the electric motor. The bearing sections and the magnet section are preloaded against each other. Furthermore, the bearing sections and the magnet section are centered relative to each other by means of a centering arrangement engaging an outer edge, with the bearing sections and the magnet section each bearing axially against each other. Disclosure of the invention

[0004] The object of the invention is to optimize an axial fluid bearing point according to the preamble of claim 1, in particular for use in a gas supply device with a very fast rotating rotor.

[0005] The problem is solved at an axial fluid bearing point with two axial foil bearing assemblies, each comprising at least one bearing foil, which are radially arranged within a housing circumferential surface of a receiving space and assigned to two axially opposite housing end faces of two housing bodies, by holding the axial foil bearing assemblies at an axial distance from each other by means of at least one guide and / or retaining geometry provided on a cover foil of the respective axial foil bearing assembly. The receiving space for the two axial foil bearing assemblies and an axially arranged axial bearing disk of a rotor is provided in a housing, for example, a gas supply device such as an air compressor, for the axial support of the rotor. An air compressor, also called a compressor, is a device for compressing gases, which increases the pressure of the gas, for example, air, by reducing the gas volume.Such an air compressor is used, for example, to operate fuel cells. Typically, the air compressor has a compressor impeller driven by a shaft from a motor, which in turn comprises a rotor and a stator. The rotor is a rotating component that ensures the compression of any gas or air drawn into the compressor, as the gas or air is moved through the compressor's compression chamber. Another essential component of air compressors is an axial air bearing, which allows axial movement of the rotor in the longitudinal direction within the compressor. The advantage of the axial air bearing is that the rotor can move axially to accommodate thermal expansion or other movements that occur during operation.This significantly reduces friction and wear, thus substantially increasing the compressor's service life. Typically, the axial air bearing in the compressor is designed to provide sufficient free space for axial rotor movement while simultaneously ensuring stable positioning within the compressor. The compressor housing is preferably multi-part. For assembly purposes, the axially opposite housing end faces are formed on two separate housing bodies. However, it is also possible for the two housing bodies to be integrally joined if assembly with an axial bearing disc is facilitated by other means, such as a multi-part axial bearing disc. The fluid used to operate the bearing is preferably a gas, such as air. Therefore, such an axial bearing is also referred to as a gas bearing or an air bearing.The axial foil bearing arrangements preferably comprise more than one bearing foil, preferably at least one spring foil and at least one cover foil. Depending on the embodiment, the axial foil bearing arrangements can also comprise several spring foils and optionally several cover foils. The claimed embodiment of the axial fluid bearing point offers, among other advantages, the elimination of a spacer, which is arranged axially between the two axial foil bearing arrangements in conventional axial fluid bearing points. This simplifies the design of the axial fluid bearing point. Furthermore, the elimination of the otherwise required spacer reduces manufacturing and assembly costs for the axial fluid bearing point.

[0006] A preferred embodiment of the axial fluid bearing arrangement is characterized in that at least one of the axial foil bearing arrangements comprises a cover foil with a circumferential edge region which, to provide a guide and / or retaining geometry on the cover foil, has a curved guide and retaining section that is axially clamped radially against the housing circumferential surface. This offers, among other advantages, that this axial foil bearing arrangement can be mounted quickly and easily and positioned and held in the receiving space on its associated axial housing end face. The cover foil is also referred to as the top foil. In addition to the cover foil, the axial foil bearing arrangement preferably comprises at least one spring foil, also referred to as a beam foil.

[0007] Another preferred embodiment of the axial fluid bearing point is characterized in that the circumferential edge region of the cover film is curved away from the housing end face associated with the axial film bearing arrangement. This further simplifies the assembly of this axial film bearing arrangement.

[0008] Another preferred embodiment of the axial fluid bearing arrangement is characterized in that at least one of the axial foil bearing arrangements comprises a cover sheet on which an additional retaining element with a guide and / or retaining geometry is formed, with which this axial foil bearing arrangement is held on its associated axial housing end face. The additional retaining element can also be combined with the previously described embodiment of the guide and / or retaining geometry on the cover sheet. However, the retaining element on the cover sheet can also be used alone with its guide and / or retaining geometry. It is particularly advantageous to use several retaining elements to hold the axial foil bearing arrangement on its associated axial housing end face. These retaining elements are then advantageously arranged on the circumference of the cover sheet, preferably evenly distributed.This further simplifies the assembly of the axial foil bearing arrangement with the retaining elements on the cover foil.

[0009] Another preferred embodiment of the axial fluid bearing point is characterized in that the retaining element is integrally connected to the cover sheet. The cover sheet with the retaining element is, for example, made of a suitable sheet metal material. The cover sheet with the retaining element is manufactured, for example, by stamping and forming. Other conventional manufacturing methods, such as etching, are also applicable. The retaining element is bent out of the cover sheet. This ensures in a simple manner that the retaining element cannot normally detach from the cover sheet, as might be possible with a separate retaining element.

[0010] Another preferred embodiment of the axial fluid bearing point is characterized in that the retaining element comprises a snap hook at a free end, which engages behind the associated axial foil bearing assembly. This significantly simplifies pre-assembly of the axial foil bearing assembly. When installing the pre-assembled axial foil bearing assembly, the retaining recess then serves only to receive the snap hook, without the hook snapping into or engaging with the retaining recess.

[0011] Another preferred embodiment of the axial fluid bearing point is characterized in that the retaining element comprises a snap hook at a free end, which snaps into or engages in a complementary retaining recess. This ensures in a simple manner that this axial foil bearing arrangement is held axially on the housing end face of the associated housing body.

[0012] Another preferred embodiment of the axial fluid bearing point is characterized in that the retaining element extends through at least one through-hole in the axial foil bearing arrangement. The through-hole extends through all bearing foils following the cover foil. These subsequent bearing foils are preferably spring foils. Due to the integral formation of the retaining element with the cover foil, the cover foil is held axially stable against the housing end face of the associated housing body by the retaining element and the subsequent bearing foils of the axial foil bearing arrangement.

[0013] Another preferred embodiment of the axial fluid bearing point is characterized in that the housing circumferential surface provides a guide geometry for the axial foil bearing assemblies during their installation. This simplifies the installation process. The housing circumferential surface can be provided with lead-in chamfers to further simplify the installation of the axial foil bearing assemblies.

[0014] In a method for mounting two axial foil bearing assemblies at a previously described axial fluid bearing location, the above-mentioned problem is solved alternatively or additionally by first inserting a first axial foil bearing assembly into the receiving space and positioning and holding it in contact with its associated axial housing end face by means of its guide or holding geometry provided on the cover foil, then positioning a rotor with an axial bearing disk, before inserting a second axial foil bearing assembly into the receiving space and positioning and holding it in contact with its associated axial housing end face by means of its guide and / or holding geometry also provided on the cover foil, such that the two axial foil bearing assemblies are held at a defined axial distance from each other in the receiving space.A spacer, otherwise required between the two axial foil bearing arrangements, can advantageously be omitted. The housing body with the first or second axial foil bearing arrangement constitutes a pre-assembled unit, which significantly simplifies the manufacturing and assembly of the axial fluid bearing point.

[0015] The invention further relates to an axial foil bearing arrangement, a bearing foil, a cover foil and / or a housing body for an axial foil bearing arrangement at a previously described axial fluid bearing location. The aforementioned parts are available separately.

[0016] The invention may also relate to a previously described pre-assembly unit.

[0017] The above-mentioned problem is solved alternatively or additionally by a gas supply device, in particular an air compressor, with a rotor which is axially supported by at least one previously described axial fluid bearing point.

[0018] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawing. Brief description of the drawing

[0019] They show: Fig. 1 an electric machine with a multi-part rotor shaft in longitudinal section; Fig. 2 an enlarged section from Fig. 1 with an axial fluid bearing point according to a first embodiment; Fig. 3 an excerpt from Fig. 2 according to a second embodiment; the Fig. 4 to 6 three design variants of a guide and / or holding geometry at the circumferential edge area of ​​a cover film of an axial film bearing arrangement; Fig. 7 a spring foil of the axial foil bearing arrangement in a top view; and Fig. 8 A cover sheet of the axial foil bearing arrangement in a top view. Description of the exemplary implementations

[0020] In Fig. Figure 1 shows a gas supply device designed as an electrically driven turbomachine 1, comprising a compressor wheel 2 and a turbine wheel 4, in longitudinal section. The compressor wheel 2 is arranged on a compressor side 3 of the turbomachine 1. The turbine wheel 4 is arranged on a turbine side 5 of the turbomachine 1.

[0021] The turbine wheel 4 is driven by the compressor wheel 2. The two wheels 2 and 4 belong to a rotating assembly 6. The rotating assembly 6 includes a motor shaft 7 to provide a rotationally fixed connection between the compressor wheel 2 and the turbine wheel 4. The motor shaft 7 is partially designed as a hollow shaft and is rotatable about a pivot axis 8.

[0022] For electric drive, the turbomachine 1 comprises an electric machine 9. The electric machine 9 is designed as an electric motor with a motor housing 10 and a motor winding 11. A magnet 12, designed as a permanent magnet, is arranged in the motor shaft 7, which is designed as a hollow shaft.

[0023] In operation within a fuel cell system, the compressor wheel 2 of the turbomachine 1 is driven firstly by the turbine wheel 4. Secondly, the compressor wheel 2 is driven by the electric motor 9.

[0024] The drive unit 6 with the motor shaft 7 is rotatably mounted in the motor housing 10 of the electric machine 9 by means of two radial bearings 13, 14. The radial bearings 13, 14 are advantageously designed as foil air bearings.

[0025] On compressor side 3, a compressor spiral casing 15 is attached to the motor housing 10. The compressor spiral casing 15 includes a compressor inlet 16, through which air to be compressed is supplied to the turbomachine 1.

[0026] On turbine side 5, a turbine spiral casing 17 is attached to the motor housing 10. The turbine spiral casing 17 includes a turbine outlet 18 through which expanded air exits. The energy generated during the expansion of the air is used to drive the compressor wheel 2.

[0027] The motor shaft 7 can also be called a rotor shaft because it serves to form a rotor 19 in the electric machine 9. The rotor 19 comprises a magnetic section 20 in which the magnet 12 is arranged. Two shaft sections 21, 22 are attached to the opposite ends of the magnetic section 20. The magnet 12 is surrounded in the magnetic section 20 by a bandage 23, which can also be called a sleeve.

[0028] In Fig. 1 The rotor 19 is axially supported by an axial bearing disk 25 at an axial fluid bearing point 24. The axial fluid bearing point 24 is designed as an axial air bearing with two axial foil bearing arrangements, which are in Fig. 2 are designated with reference numbers 31 and 32.

[0029] In Fig. 2 is the axial fluid bearing point 24 from Fig. Figure 1 is enlarged, but without the axial bearing disk 25. The two axial foil bearing assemblies 31, 32 are accommodated in a receiving space 35 of a housing 27, which is, for example, the motor housing 10 of the turbomachine 1 in Fig. 1 corresponds to.

[0030] The housing 27 has an internal circumferential surface 30. In Fig. 2 on the left, the housing 27 additionally includes a housing body 28. In Fig. 2 on the right, the housing 27 comprises a housing body 29. The two housing bodies 28 and 29 have two mutually facing housing end faces 33, 34 radially within the housing circumferential surface 30 of the housing 27.

[0031] The housing end faces 33 and 34 define the receiving space 35 for the two axial foil bearing arrangements 31 and 32 in the axial direction. In the radial direction, the receiving space 35 for the two axial foil bearing arrangements 31, 32 is defined by the housing circumferential surface 30, which can also be referred to as the inner housing circumferential surface 30.

[0032] The two axial foil bearing arrangements 31, 32 each comprise at least one bearing foil 26, 38. The axial foil bearing arrangement 31 comprises a cover foil 36 and several spring foils 37. The axial foil bearing arrangement 32 comprises a cover foil 39 and several spring foils 40.

[0033] In the Fig. 2 and Fig. Figure 3 shows guide and / or retaining geometries 41 to 43, which enable the axial foil bearing assemblies 31, 32 to be mounted in the receiving space 35 of the housing 27 without the need for a spacer such as those used in conventional air compressors. This simplifies the design of the air compressor. Manufacturing costs, especially assembly costs, are reduced.

[0034] The axial foil bearing arrangement 31 can advantageously be combined with the housing body 28 in a pre-assembly unit. The same applies to the axial foil bearing arrangement 32 with the housing body 29. Fig. Figure 2 shows that the axial foil bearing arrangement 31 with the housing body 28 is held in the housing 27 on the housing end face 33 solely by means of the guide and / or retaining geometry 41.

[0035] The axial foil bearing arrangement 32 is mounted and fastened using the guide and / or retaining geometry 43 in addition to the guide and / or retaining geometry 42. The two guide and / or retaining geometries 41, 42 each comprise a circumferential edge region 47, 48, which is formed on the respective cover foil 36, 39.

[0036] In the peripheral border areas 47, 48, the cover sheets 36, 39 are, as can be seen in Fig. 2 is designed with a curved shape. A corresponding radius of curvature is arranged on the facing surfaces of the cover sheets 36, 39. The circumferential edge regions 47, 48 are curved in such a way that the cover sheets 36, 39 abut the inner housing circumferential surface 30 of the housing 27.

[0037] Furthermore, the circumferential edge regions 47, 48 of the essentially circular disc-shaped cover films 36, 39 are pre-tensioned against the inner housing circumferential surface 30. This ensures that the two axial film bearing arrangements 31, 32 are clamped axially in their respective mounting positions in the receiving space 35.

[0038] In Fig. Figure 2 shows that the axial foil bearing arrangement 32 is mounted on the housing body 29 with the guide and / or retaining geometry 43 in addition to the use of the guide and / or retaining geometry 42. The guide and / or retaining geometry 43 includes an additional retaining element 53. The additional retaining element 53 is bent out of the cover foil 39.

[0039] The retaining element 53 is angled away from the cover film 39. The retaining element 53 extends through a through-hole that extends axially through all bearing films of the axial film bearing arrangement 32 following the cover film 39.

[0040] At his in Fig. 2 At its right end, the retaining element 53 has a snap hook 55 which engages the Fig. The bearing foil 57, located on the far right of the axial foil bearing assembly 32, engages behind the guide and / or retaining geometry 42. This holds all bearing foils of the axial foil bearing assembly 32 together axially. This significantly simplifies the pre-assembly of this axial foil bearing assembly 32. The pre-assembled axial foil bearing assembly 32 can then be mounted and held in the receiving space 35 using the guide and / or retaining geometry 42. In the assembled state of the axial foil bearing assembly 32, the retaining recess 57 serves only to receive the snap hook 55.

[0041] Unlike in Fig. As shown in Figure 2, the retaining recess 57 can also be designed with an undercut which, in conjunction with the snap hook 55 or another snap hook on a further retaining element, forms a snap connection with which the axial foil bearing arrangement 32 is held axially on the housing end face 34, wherein the snap hook engages or snaps into the retaining recess 57 of the housing body 29 which is provided with the undercut.

[0042] In Fig. Figure 3 shows that the two axial foil bearing assemblies 31, 32 can only be positioned and held axially relative to their associated housing end faces 33, 34 in the receiving space 35 using the guide and / or retaining geometries 41, 42. This significantly simplifies the assembly of the axial foil bearing assemblies.

[0043] In the Fig. Figures 4 to 6 show three exemplary embodiments of how differently the circumferential edge area 47 of the cover film 36 with the retaining section 65 can be designed to represent the guide and / or retaining geometry 41.

[0044] In Fig. 4, the stopping section 65 is only slightly curved. In Fig. 5 is the holding section 65 essentially slightly more than perpendicular to the cover foil 36 in Fig. 5 angled to the right, with the free end of the retaining section 65 still slightly curved downwards. In Fig. The retaining section 65 is aligned at an angle 52 to the cover film 36. The angle 52 is preferably about forty-five degrees.

[0045] In the Fig. 7 and Fig. Figure 8 shows exemplary embodiments of the spring foil 37 and the cover foil 39, each shown individually in a top view. The spring foil 37 comprises an annular body 49 from which retaining fingers 50 extend radially inwards. A spring element 51 is attached to each of the retaining fingers 50. Radially inwards, the spring body 37 has a central through-hole for guiding the rotor through.

[0046] The cover sheet 39 comprises an outer ring 61 and an inner ring 62. The inner ring 62 has a central through-hole for guiding the rotor through. The inner ring 62 is integrally connected to the outer ring 61 by connecting webs 63.

[0047] In Fig. Figure 8 shows that the circumferential edge region 48, used to represent the guide and / or retaining geometry 42, is not completely curved. Fig. Figure 8 shows that the guide and / or holding geometry 42, like the guide and / or holding geometry 41, has a curved guide and holding section 65 which, in the installed state, is axially clamped radially against the housing circumferential surface 30.

[0048] In Fig. Figure 8 further shows that the connecting body 56 of the additional retaining element 53, which serves to represent the guide and / or retaining geometry 43 on the cover film 39, extends from the outer ring 61. Starting from the outer ring 61, the connecting body 56 initially extends radially inwards before extending axially through the spring foils 40 of the axial foil bearing arrangement 32. The snap hook at the end of the connecting body 56 of the retaining element 53 formed on the cover film 39 is shown in the illustration of the Fig. 8 not visible. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 202022102710 U1

[0002] DE 112012002901 T1

[0003]

Images