WO2020099226A1

WO2020099226A1 - Air bearing

Info

Publication number: WO2020099226A1
Application number: PCT/EP2019/080470
Authority: WO
Inventors: Jochen Wessner; Felix WIEDMANN
Original assignee: Robert Bosch Gmbh
Priority date: 2018-11-14
Filing date: 2019-11-07
Publication date: 2020-05-22
Also published as: DE102018219389A1

Abstract

The invention relates to an air bearing (10) of a compressor and to the use of the air bearing. The air bearing comprises an outer ring (12), which comprises an opening delimited by an inner lateral surface (14), in which opening a spring film (20) is supported. Said spring film extends around an upper film (22), which faces a shaft to be supported, in particular a compressor shaft. The outer ring comprises a recess (24), in which end geometries (30) and ends (88) of the spring film and of the upper film are fastened.

Description

Luftlaaer

Technical field:

The invention relates to an air bearing for a bearing unit of a compressor of a fuel cell system with an outer ring in which a spring film is supported, which encloses an upper film. The invention further relates to a compressor for a fuel cell system with the air bearing and to the use of the air bearing in a fuel cell system of a vehicle.

State of the art:

A fuel cell is a galvanic cell, which converts chemical reaction energy of a continuously supplied fuel and an oxidizing agent into electrical energy and thereby provides a voltage. A fuel cell is therefore not an electrochemical one

Energy converter. In known fuel cells, in particular

Hydrogen (H2) and oxygen (02) are converted into water (H20), electrical energy and heat. Several can increase the voltage

Fuel cells are combined into a fuel cell unit and electrically connected in series.

A fuel cell system comprises a fuel cell unit which has a plurality of fuel cells, each comprising an anode and a cathode. Hydrogen as fuel is stored in a compressed gas storage and fed to the anode. Air which oxygen as

Contains oxidizing agent, the cathode is preferably supplied by an electrically driven compressor or compressor. Such a compressor comprises a bearing unit, which in particular comprises an air bearing and a shaft rotatably mounted in the air bearing. The rotatably mounted shaft rotates with one during operation of the compressor

relatively high speed, in the order of 100,000

Revolutions per minute.

From EP 2 600 007 A2 a motor vehicle system device is known which has a fuel cell unit and a compressor. The compressor, which conveys air to the fuel cell assembly, comprises an air bearing which acts as an aerostatic bearing at low speed and at high speed

Speeds is operated as an aerodynamic bearing. A fluid film radial bearing emerges from US Pat. No. 5,915,841. The fluid film radial bearing comprises a sleeve with an inner bore in which a shaft rotates. The bearing also includes a plurality of resilient foils and foil support springs which are arranged in the inner bore and surround the rotating shaft.

A radial bearing is known from US Pat. No. 5,427,455 A, which holds an insert bushing with an opening in which a rotor rotates. The radial bearing has a spring foil member and a fluid foil member, which are arranged within the opening. The opening in the insert bush has a non-circular inner contour.

Presentation of the invention:

According to the invention, an air bearing for a bearing unit of a compressor is proposed, which comprises an outer ring that is one of a

Includes lateral surface limited central opening in which a spring film is supported. This encloses an upper film which faces a shaft to be supported. The outer ring comprises a recess in which the end geometries and ends of the spring foil and top foil are fixed. The recess, for receiving the end geometries and the ends of spring foil and top foil, can be in

manufacturing technology are extremely easy to manufacture. Furthermore, the chosen arrangement of the spring film, which is covered by the upper film, can brace the end geometries or the ends of the two films against one another and fix them. In a further embodiment of the solution proposed according to the invention, the air bearing is designed such that both the end geometries and the ends of the spring foil and the top foil are fixed in the circumferential direction of the outer ring. Advantageously, both the end geometries and the ends of the spring foil and the top foil are also fixed in the axial direction of the outer ring.

In the air bearing proposed according to the invention, the spring foil is attached to the by a number of supports designed in the shape of an arc

Supported inner circumferential surface of the outer ring. This creates a free space between the spring foil and the inner lateral surface, which enables the shaft to be accommodated in the air bearing to be resiliently supported.

In an alternative embodiment of the air bearing proposed according to the invention, the spring foil, viewed in the circumferential direction of the outer ring, can comprise a number of punchings which are spaced apart tangentially, the outer edges of which are each supported on the inner circumferential surface of the outer ring. According to this solution, the arched supports can be dispensed with, since the resilient mounting of the spring foil is provided by the spring foil itself or by punched-out, for example, rectangularly shaped punched-outs. The punched holes are advantageously with their

Outer edges on the inner surface of the outer ring. Due to the resilience inherent in the spring foil, the punched-out areas also result in a resilient mounting of the spring foil with respect to the outer ring of the air bearing, so that the structural elements arch-shaped supports could be saved in this case.

In a particularly advantageous manner in terms of production technology, the air bearing is constructed in such a way that the depression, which extends essentially in the axial direction of the outer ring on the inner circumferential surface of the outer ring, can be produced by broaching, by non-circular grinding or by a milling process.

In the air bearing proposed according to the invention, different end geometries can be formed with respect to the end geometry of one end of the top film. So cover a first end geometry or a second End geometry of the top film a first end of the spring film and simultaneously serve as a support or support surface for second ends of the spring film and top film. For example, in the air bearing proposed according to the invention, the first end geometry of the top film can be designed as a hook-shaped 180 ° bend. Alternatively, there is the possibility of designing a second end geometry of the upper film in such a way that a support leg is formed at the end thereof, which is seen in the recess in the inner circumferential surface of the outer ring in the radial direction of the outer ring.

A third advantageous end geometry of the upper film is provided in that a tab is provided which is supported on a side wall of the recess in the outer ring and extends within the recess in the outer ring below the second ends of the upper film and the spring film.

In a further embodiment of the solution proposed according to the invention, further end geometries of the top film can be shaped as complementary shaped tabs and recesses, so that the top film in

Circumferential direction can be plugged together.

When the recess is formed on the inner circumferential surface of the outer ring, the recess can be designed with recess walls that are narrowed by an angle 02 to the central axis of the outer ring. As a result, the depression has an approximately dovetail-shaped contour, which offers advantages with regard to the contact of the end geometries or the ends of the spring film and the top film.

It is also possible to design the depression with respect to the angle a-index such that the depression walls which delimit the depression on the inner circumferential surface of the outer ring are realized by insert parts, so that the depression is recessed radially inwards with respect to the central axis of the outer ring .

Furthermore, the invention relates to a compressor comprising an air bearing according to the invention. Finally, the invention relates to the use of the air bearing proposed according to the invention in a fuel cell system of a vehicle.

Advantages of the invention:

The advantages of the air bearing proposed according to the invention are that the recess on the inner circumferential surface of the outer ring, as proposed according to the invention, enables the upper film and the spring film to be reliably fixed. In particular, the recess has a geometry that is inexpensive to produce. The upper film has a geometry in a further dimension, in particular a radial elevation or rounding, which can be produced simply by reshaping and which is formed at one end of the upper film. With this geometry, for example in the form of a 180 ° bend or in the form of a support leg, the overlapping top film and spring film can be supported radially in the radial direction on the bottom of the depression of the inner circumferential surface of the outer ring.

Through the solution proposed according to the invention, the spring film surrounded by the upper film can also be fixed by positioning it below the upper film, both in the circumferential direction with respect to the outer ring and in the axial direction with respect to the outer ring. With all

Embodiment variants of the solution proposed according to the invention, the spring foil of the air bearing is fixed both in the circumferential direction and in the axial direction by the top foil which faces the shaft to be supported.

Brief description of the drawings

The invention is described in more detail with reference to the drawing.

It shows:

FIG. 1 shows a compressor for a fuel cell system,

FIG. 2 shows a shaft mounted in air bearings, Figure 3 is a side perspective view of an inventive

proposed air bearing with an axially extending recess on the outer ring,

Figure 4 is an enlarged view of the drawing plane

extending recess with end geometries or ends of spring foil and top foil fixed in it,

FIG. 5 shows a top view of the upper film shown unwound,

FIG. 6 shows a perspective side view of a further embodiment variant of the air bearing proposed according to the invention with a depression extending in the axial direction of the outer ring,

FIG. 7 shows an illustration of the end geometry of the top film, recorded in the depression,

Figure 8 is a developed view of the top film with recess and

Clip and

Figures 8.1, 8.2, 8.3 connection variants of the upper film of the air bearing and

Figure 9 shows a section of an air bearing with a shaft to be supported, one

Upper foil and a spring foil, whereby individual spring punchings are applied to the inner surface of the outer ring from the spring foil.

Design variants:

Figure 1 shows a compressor 6 for a fuel cell system.

FIG. 1 shows a compressor 6 in a side view, in which a shaft 80 to be supported, for example a compressor shaft 8, is received. Air is placed in a fuel cell stack above the compressor 6

Funded fuel cell system. Figure 2 shows a shaft mounted in air bearings 10.

FIG. 2 shows a section of part of the compressor 6. The shaft (80) to be supported in it, in particular the compressor shaft 8, is supported in two air bearings 10 shown at a distance from one another in the illustration according to FIG. This results in an essentially friction-free mounting of the compressor shaft 8 or a shaft 80 to be supported.

FIG. 3 shows an essentially cylindrical air bearing 10, which comprises an outer ring 12. The outer ring 12 has an opening which is delimited by an inner circumferential surface 14. A spring foil 20 is embedded in the outer ring 12. The spring foil 20 extends in the circumferential direction along the inner circumferential surface 14 of the outer ring 12 and is resiliently supported by a plurality of supports 18 which are designed in the form of an arc. The individual supports 18 are, for example, in the 9 o'clock, 12 o'clock and 3 o'clock positions. Due to the arcuate supports 18 between the spring film 20 and the

Inner circumferential surface 14 a gap-shaped free space 16 is formed, which allows a spring-loaded mounting of a shaft, not shown in Figure 3, to be supported. The spring film 20 as shown in FIG. 3 encloses an upper film 22. The ends 88, 90, 92, 94 of the spring film 20 and the upper film 22 are fixed in a recess 24. The recess 24 extends on the

Inner lateral surface 14 of the outer ring 12 in the axial direction of the outer ring 12. The recess 24 can be produced in a particularly simple manner in terms of production technology by broaching, non-circular grinding or by milling. The depression 24 is formed by opposing depression walls 26 and a depression bottom 28.

As can be seen from the perspective illustration according to FIG. 3, the top film 22 has a first end geometry 30, which is designed here, for example, as a 180 ° bend 32 in the form of a hook. The 180 ° bend 32 is designed such that the first end 90 of the upper film 22, the areas of the depression 24 cover the spring film 20 or its first end 88, is supported on one of the depression walls 26 of the depression 24 of the outer ring 12. FIG. 4 shows an enlarged illustration of the depression 24 extending into the plane of the drawing with end geometries 30, 34, 66, 72, 74 or ends 88, 90, 92, 94 of the spring foil 20 and the top foil 22 fixed therein.

Figure 4 shows the outer ring 12 only in partial reproduction. It can be seen from the illustration according to FIG. 4 that in this embodiment variant the top film 22 has a second end geometry 34. In the illustration according to FIG. 4, the second end geometry 34 is designed as a support leg 36. The support leg 36 covers the first end 88 of the spring film 20 and is bent in the radial direction so that a first end 90 of the upper film 22 is supported on the recess bottom 28 of the recess 24 of the outer ring 12.

At the same time, the support leg 36 serves as a contact surface 38 both for a second end 92 of the spring foil 20 and for a second end 94 of the

Upper foil 22. All ends 88, 90, 92, 94 of the upper foil 22 and the spring foil 20 end within the recess 24 and are fixed there in the radial direction and in the circumferential direction with respect to the outer ring 12.

The depression 24 on the inner circumferential surface 14 of the outer ring 12 is at an angle ai cf. Reference numeral 40 or manufactured at an angle 02 reference numeral 42. By producing the depression 24 with the angle 02 (see reference numeral 42), the depression 24 is laterally delimiting

Recess walls 26 inclined with respect to the central axis of the outer ring 12, i. H. narrowed in the radial direction with respect to the central axis of the outer ring 12. This narrowing due to the angle 02, cf. Reference numeral 42 in FIG. 4 gives the geometry of the recess 24, seen in the drawing plane according to FIG. 4, a dovetail-shaped contour.

5 shows a top view of the unwound upper film.

According to the illustration in FIG. 5, the top film 22 has a first one

Upper film end 46 and a second upper film end 48. Furthermore, opposite ends 88, 92 of the spring foil 20 are shown in the development according to FIG. 5. The spring foil 20 can comprise cutouts, as indicated in the developed representation according to FIG. 5. According to the 5, the ends of the spring film 20, which is only partially shown, are located on the upper film 22, which is schematically indicated as a rectangle.

FIG. 6 shows a perspective side view of a further embodiment variant of the air bearing 10 proposed according to the invention, with the recess 24 extending in the axial direction of the outer ring 12.

The air bearing 10 shown in FIG. 6 likewise comprises the outer ring 12, on the inner lateral surface 14 of which an arch-shaped support 18 is located in the 9 o'clock position, 12 o'clock position and 3 o'clock position. The spring foil 20 is elastically supported via these supports 18. The spring foil 20 in turn encloses the top foil 22.

Analogous to the embodiment variant of the

Air bearing 10 proposed according to the invention is formed on the inner circumferential surface 14 of the outer ring 12, the groove-shaped recess 24 extending in the axial direction with respect to the outer ring 12. The recess walls 26 (see also illustration according to FIG. 5) are made analogously to the recess 24 according to the side view in FIG. 4, as far as the angles ai (compare reference number 40) and the angle 02 (compare reference number 42 in FIG. 4) are concerned. In contrast to the design variants of the first end geometry 30 of the top film 22 in FIG. 3 and the second end geometry 34 of the top film 22, as is shown in FIG. 4, the top film 22 is located in FIG

Representation according to Figures 6 and 7 at the end of the top film 22 a

Bend 60. This bend 60 forms with a tab 62 branching from a web 64 and extending in the circumferential direction a third end geometry 66 of the top film 22.

FIG. 6 shows that the third end geometry 66 of the top film 22 covers the first end 88 of the spring film 20, the web 64 runs into the recess 24 in the radial direction and merges into the tab 62 in the circumferential direction within the recess 24. Both the second end 92 of the spring film 20 and the second end 94 of the upper film 22 protrude into the undercut formed thereby. The first end 90 of the top film 22, formed by the tab 62, lies on one of the inclined recess walls 26 of the recess 24 extending in the axial direction in the outer ring 12.

FIG. 7 shows the third end geometry 66 in an enlarged representation. 5 also shows that the bend 60 of the upper film 22 covers the first end 88 of the spring film 20 and that the web 64 initially runs in the radial direction into the recess 24 into which the

tab 62 oriented in the essential circumferential direction. Both the second end 92 of the spring film 20 and the second end 94 of the top film 22 lie inside the recess 24 and on an outside of the web 64.

The depression 24 according to FIG. 7 is made analogously to the depression 24 of the outer ring 12 according to FIG. 4, as far as the angles ai (compare reference number 40) and the angle 02 (compare reference number 42) are concerned. The angle 02 (see reference numeral 42) could also be represented by insert parts. By choosing according to the angle 02 (see reference numeral 42) the narrowing of the upper side of the recess 24 is achieved, inclined recess walls 26 are created which give the recess 24 seen in the axial direction of the outer ring 12 a dovetail-shaped contour

A developed top film 22 can be seen in the illustration according to FIG.

It can be seen from the illustration in FIG. 8 that a fourth end geometry 72 and a fifth end geometry 72 are in each case in the end regions thereof

End geometry 74 is formed. The fourth end geometry 72 and the fifth end geometry 74 are distinguished by the fact that they comprise at least one insert tab 70 and at least one recess 78. When the top film 22 is bent, there is an overlap area.

In the representations according to Figures 8.1, 8.2 and 8.3 are

Connection variants of the upper film of the proposed air bearing 10 according to the invention can be seen in detail.

In the figure sequence according to FIGS. 8.1, 8.2 and 8.3, a spring foil 20 and an upper foil 22 are accommodated one above the other in the outer ring 12 of the air bearing 10. In the embodiment variant according to FIG Insert tab 70 of the top film 22 is inserted into the corresponding recess 78 of the opposite second end 94 of the top film 22. In this embodiment variant, the first end 90 of the top film 22 ends as an angle 60 with the tab 62. In the mounted state shown in FIG. 8, this extends in the recess 24 parallel to the recess bottom 28 of the recess 24 extending into the plane of the drawing on the inner lateral surface 14 of the outer ring 12.

In the variant according to FIG. 8.2, the first end 90 of the top film 22 ends as a support leg 36 in that a recess 78 is provided. The opposite second end 92 of the spring foil 20 is inserted into this. The support leg 36 extends essentially in the radial direction into the recess 24, which extends on the outer ring 12 into the plane of the drawing according to FIG. 8.2.

Finally, FIG. 8.3 shows that the second end 94 of the upper film 22 comprises a web 64 which is of rounded design and surrounds the first end 88 of the spring film 20 underneath it in a semicircular shape. In this

In an embodiment variant, the first end 90 of the top film 22 ends as a tab 62 which extends essentially parallel to the recess bottom 28 of the recess 24.

FIG. 9 shows an illustration of an air bearing 10, the spring film 20 of which assumes the function of an elastic bearing.

As can be seen in FIG. 9, the air bearing 10 partially shown there comprises the outer ring 12. A shaft 80 to be supported or its shaft

Shaft jacket 82, as seen in the radial direction, faces the top of top film 22. There is an air gap between the shaft 80 to be supported or its shaft jacket 82 and the upper side of the upper film 22; as well as between the underside of the top film 22 and the top of the spring film 20.

The elasticity of the spring film 20 with respect to the inner surface 14 of the outer ring 12 is produced in that individual punchings are made from the material of the spring film 20, spaced apart in the tangential direction 84 are executed. The punched-outs 84 run essentially straight and not curved, so that the outer edges 86 of the individual in the tangential direction of the spring foil 20 are spaced apart from one another to punched-outs 84, on the inner lateral surface 14 of the outer ring 12. This creates free spaces 16, since the curved part of the spring foil 20 is not on the

Inner surface 14 of the outer ring 12 rests, but due to the

Punched holes 84 are lifted from the space 16 of an air gap. This gives the spring foil 20 and thus the air bearing 10 its elasticity. The invention is not restricted to the exemplary embodiments described here and the aspects emphasized therein. Rather, a large number of modifications are possible within the scope specified by the claims, which are within the scope of professional action.

Claims

Expectations

1. air bearing (10) for a compressor (6) with an outer ring (12), which comprises a central opening delimited by an inner lateral surface (14), in which a spring foil (20) is supported, which encloses an upper foil (22), which faces a shaft (80) to be supported, in particular a compressor shaft (8), characterized in that the outer ring (12) comprises a recess (24) in which end geometries (30, 34, 66, 72, 74) and Ends (88, 90, 92, 94) of the spring foil (20) and the top foil (22) are fixed.

2. Air bearing (10) according to claim 1, characterized in that the end geometries (30, 34, 66, 72, 74) and the ends (88, 90, 92, 94) in the recess (24) in the circumferential direction of the outer ring ( 12) are fixed.

3. Air bearing (10) according to claim 1, characterized in that the end geometries (30, 34, 66, 72, 74) and the ends (88, 90, 92, 94) in the recess (24) in the axial direction of the outer ring ( 12) are fixed.

4. Air bearing (10) according to claim 1, characterized in that the spring film (20) is resiliently supported by a number of arcuate supports (18) on the inner circumferential surface (14) of the outer ring (12).

5. Air bearing (10) according to claim 1, characterized in that the spring foil (20), viewed in the circumferential direction, comprises a number of tangentially spaced punched-out portions (84), the outer edges (86) of which lie on the inner lateral surface (14) of the outer ring (12). support resiliently.

6. Air bearing (10) according to claim 1, characterized in that the recess (24) in the inner circumferential surface (14) of the outer ring (12) is made by broaching, non-circular grinding or milling.

7. Air bearing (10) according to claim 1, characterized in that the first end geometry (30) and second end geometry (34) of the upper film (22) cover a first end (88) of the spring film (20) and as contact or support surfaces for second ends (92, 94) of the spring foil (20) and the upper foil (22) are used.

8. Air bearing (10) according to claim 7, characterized in that the first end geometry (30) of the upper film (22) is a 180 ° bend (32).

9. Air bearing (10) according to claim 7, characterized in that the second end geometry (34) of the upper film (22) comprises a support leg (36) which - seen in the radial direction of the outer ring (12) - in the recess (24 ) supports.

10. Air bearing (10) according to claim 1, characterized in that a third end geometry (66) of the upper film (22) is one on one

Has recess wall (26) of the recess (24) supporting tab (62), which extends within the recess (24) below the second ends (92, 94) of the top film (22) and the spring film (20).

11. Air bearing (10) according to claim 1, characterized in that a fourth end geometry (72) and a fifth end geometry (74) of the upper film (22) are shaped as complementary to each other shaped at least one insertion tab (70) and at least one recess (78) are.

12. Air bearing (10) according to claim 1, characterized in that the recess (24) comprises recess walls (26) which run at an angle 02 (42) narrowed to the central axis of the outer ring (12).

13. Air bearing (10) according to claim 12, characterized in that the angle 02 (42) around which the recess walls (26) narrows

Center axis of the outer ring (12) run, is realized by insert parts.

14. Compressor (6) for a fuel cell system comprising at least one air bearing (10) according to one of the preceding claims.

15. Use of the air bearing (10) according to one of the preceding

Claims for a fuel cell system of a vehicle.