DE102010006018A1 - Charging device for compressing a medium and drive train for a motor vehicle with such a charging device - Google Patents

Abstract

The invention relates to a charging device (28, 41) for compressing a medium, in particular air, with a rotor (31, 39) comprising at least one compressor wheel (32, 40), which has an inner diameter (Di) and an outer one by means of at least one Diameter (Da) having bearing rings (66, 67) of a bearing device (68) is mounted in the axial direction (70, 72) of the compressor wheel (30, 40), a quotient of one of the arithmetic mean of the outer diameter (Da) and the inner diameter (Di) formed mean diameter Dax of the bearing ring (66) and an outlet diameter DV of the compressor wheel (30, 40) is at least substantially in a range, and a drive train for a motor vehicle with at least one such charging device.

Description

The invention relates to a charging device for compressing a medium, in particular of air, the type specified in the preamble of patent claim 1 and a drive train for a motor vehicle with such a charging device.

Charging devices in the form of exhaust-gas turbochargers, which comprise a rotor with a shaft which is mounted in a bearing housing by means of a bearing device, are known from series-production vehicle construction. Such a rotor has very high rotational speeds during operation of the exhaust-gas turbocharger, which lead to extremely high loads on the rotor as well as of the bearing housing, in particular over a long service life and over a long service life of the exhaust-gas turbocharger.

The DE 8717441 U1 discloses a turbocharger with a gas-static radial bearing, wherein a portion of the bearing length-engaging portion is provided from a porous sintered body. Furthermore, a supply line for the storage gas which is supplied in the interior of the shaft is provided, as well as a bearing shell divided into individual, partially overlapping segments, wherein the segments are spread by spring elements arranged between them in the region of the overlaps.

These as well as the charging devices known from the production of standard cars have further potential to further improve a bearing of a rotor rotating during operation of the charging device.

It is therefore an object of the present invention to provide a charging device for compressing a medium and a drive train for a motor vehicle with such a charging device, which have a long service life.

This object is achieved by a charging device for compressing a medium, in particular air, with the features of patent claim 1 and by a drive train for a motor vehicle with such a charging device with the features of claim 9. Advantageous embodiments with expedient and non-trivial developments of the invention are specified in the dependent claims.

aus einem aus dem arithmetischen Mittelwert des äußeren Durchmessers und des inneren Durchmessers gebildeten mittleren Durchmesser D_ax des Lagerrings und einem Austrittsdurchmesser D_V des Verdichterrads zumindest im Wesentlichen in einem Bereich von

liegt.A charging device according to the invention for compressing a medium, in particular of air, with a rotor comprising at least one compressor wheel which is mounted by means of at least one bearing ring having a diameter and an outer diameter Lagerunseinrichtung axial direction of the compressor wheel, characterized in that a quotient

from an average diameter D _{ax of} the bearing ring formed from the arithmetic mean of the outer diameter and the inner diameter and an exit diameter D _{V of} the compressor wheel at least substantially in a range from

lies.

Thus, the bearing ring of the bearing device, which is designed as an axial bearing, relative to the outlet diameter of the compressor D _{V placed} at a relatively large diameter D _ax , thus high circumferential speeds and relative movements of corresponding sliding surfaces for storage each other even at relatively low speeds of the rotor for To use a desired sufficient carrying capacity, thereby ensuring a safe and efficient storage of the rotor over a very long service life of the charger and a long service life derselbigen away. Furthermore, in this placement of the bearing ring on the large diameter sufficient areas are generally provided to cope with and support even the highest shear stresses in the axial direction of the compressor wheel and thus the rotor.

The charging device according to the invention is used, for example, as an exhaust gas turbocharger in the known manner. Likewise, it can be used in an air supply system in a drive train for a motor vehicle with a fuel cell, by means of the charging device according to the invention one of the fuel cell to be supplied air is compressible and the rotor and thus the compressor, for example by means of an electric machine, both as an electric motor and optionally as Generator for generating electrical energy can be operated, is driven. The generation of electrical energy can, for example, be such that the rotor also comprises a turbine wheel, which can be driven by an exhaust gas of the fuel cell or by an exhaust gas of an internal combustion engine (in the embodiment of the supercharger as exhaust gas turbocharger). In this case, an adjusting element is provided in the flow direction of the exhaust gas upstream of the turbine wheel, for example, by means of which a flow cross-section is adjustable, whereby the charging device over a wide range of different operating points of the fuel cell or the internal combustion engine is adaptable. This allows a particularly efficient operation of the charging device. Such a variable guide grid element can, for example, make a back pressure flap for setting an exhaust back pressure obsolete.

By the variable guide grid element and / or the mentioned counter-pressure flap a narrowest flow cross-section upstream of the turbine is adjustable, whereby the Stopfgrenze a compressor of the charging device, which is associated with the compressor, influenced and thus the charging device to a wide variety of different operating points of the fuel cell or the internal combustion engine is customizable.

In any respect, the design and arrangement of the bearing ring of the storage device of the charging device according to the invention allows a very good axial bearing of the rotor at different operating points of the charging device and even at very high axial loads.

This very good storage even at high loads and over a long service life and a long service life of the charging device allows the representation of high performance of the charging device, which is associated with high power yields and high efficiencies of the fuel cell or the internal combustion engine.

The charging device according to the invention can also act as a range extender with a gas turbine and directly coupled electric generator for electric vehicles, the storage device ensures a very good storage of the rotor in this application.

In other words, this means that the bearing of the rotor of the charging device according to the invention is applicable to at least almost any application with high-speed rotors, in which flow compressors are used and in which an axial thrust compensation is a high challenge. The storage device allows the absorption and support of high axial forces, these axial forces significantly affect the life of the storage device and thus the charging device. If the influence of these axial forces on the life of the bearing device is weighted, this influence of the axial forces should be assessed as two thirds of the total. In contrast, storage devices which at least substantially absorb forces in the radial direction of the compressor wheel, absorb unbalance forces of the rotor, which can be maintained by a fine balancing in a small frame.

The influence of gas forces on the relevant for the life of the bearing device axial forces is not or only with great effort to reduce, which makes such a design of the bearing means for supporting the rotor in the axial direction desselbigen required that even at high gas forces and thus At high axial forces secure storage is permanently guaranteed. This is realized by the storage device or the design of the bearing ring of the charging device according to the invention.

In an advantageous embodiment of the invention, the at least one bearing ring can be lubricated by means of a lubricant supply device with at least substantially liquid lubricant. This liquid lubricant is, for example, lubricating oil. Also possible is the use of water, a fuel and a liquid medium for Abgasent nitung, for example, an aqueous urea solution. It is also possible that the bearing ring is lubricated by means of a grease.

In a further embodiment, the at least one bearing ring is lubricated by means of the lubricant supply device with an at least substantially gaseous lubricant, in particular air, wherein such lubrication with air is particularly advantageous when using the charging device according to the invention in so-called zero-emission vehicles, in which by the use of Air as a lubricant Environmentally polluting emissions are avoided by leakage of lubricant.

In a further embodiment, the bearing device is at least partially designed as an air bearing device, wherein the at least one bearing ring is assigned to the air bearing device. This means that in this case an air bearing of the rotor in the axial direction of the compressor wheel and thus of the rotor is represented by the at least one bearing ring, which is also advantageous in the mentioned zero-emission vehicles due to the avoidance of polluting emissions. Hydrocarbon-containing lubricants, such as lubricating oil, are thereby substituted by air.

The invention also includes a drive train for a motor vehicle with at least one charging device according to the invention, wherein by means of the charging device a medium to be supplied to an assembly, in particular an internal combustion engine or a fuel cell to be supplied air, is compressible. Advantageous embodiments of the charging device according to the invention are to be regarded as advantageous embodiments of the drive train according to the invention and vice versa. In this case, the drive train may include the stated lubricant supply device, by means of which the bearing ring with a gaseous or liquid or grease-like lubricant is lubricated.

Further advantages, features and details of the invention will become apparent from the following description of several preferred embodiments and from the drawings. The features and feature combinations mentioned above in the description as well as the features and feature combinations mentioned below in the description of the figures and / or in the figures alone can be used not only in the respectively specified combination but also in other combinations or in isolation, without the scope of To leave invention.

The drawings show in:

1 a schematic representation of a drive train of a motor vehicle with an embodiment of the charging device according to the invention;

2 a partial sectional view of an embodiment of the charging device according to the invention;

3 a partial sectional view of an embodiment of the charging device according to the invention; and

4 a partial sectional view of an embodiment of the charging device according to the invention.

The 1 shows a drive train 8th with a fuel cell 10 , by means of which in the fuel cell 10 supplied and compressed air contained oxygen and the fuel cell 10 supplied hydrogen is recoverable to obtain electrical energy in water. The electrical energy is transmitted via lines 12 a battery 14 fed and in the battery 14 saved. Via cables 16 is the stored electrical energy an electric motor 18 can be fed, which converts the electrical energy into a torque of a shaft 20 converts, creating a motor vehicle with the drive train 8th is drivable.

The fuel cell 10 is the hydrogen from a tank 22 via a valve 24 fed. To illustrate a particularly efficient operation of the fuel cell 10 and to show high performance is that of the fuel cell 10 to be supplied and according to a directional arrow 26 sucked air first from a first charging device 28 compacted, which is a compressor 30 includes a rotor 31 having. The rotor 31 again includes one with a wave 34 of the rotor 31 rotatably connected compressor wheel 32 which is about the wave 34 from an electric motor 36 the charging device 28 can be driven.

The compressor 30 the charging device 28 thus represents a low-pressure compressor, which pre-compresses the air, whereupon it is a high-pressure compressor in the form of a compressor 38 another charging device 41 is supplied. Also the compressor 38 includes a rotor 39 that rotates with a shaft 42 connected compressor wheel 40 and a rotation with the shaft 42 connected turbine wheel 44 a turbine 46 the charging device 41 includes. The turbine 46 the charging device 41 is designed as a double-flow turbine, for example as a segment turbine whose turbine wheel 44 from an exhaust gas of the fuel cell 10 according to a directional arrow 48 is acted upon and thereby driven, causing the shaft 42 and thus the compressor wheel 40 be driven to compress the air. The air thus compressed becomes over a bladder-quantity dosage 50 and a cooler 52 the fuel cell 10 according to a directional arrow 54 fed.

Including the turbine 46 the charging device 41 high performance, it is next to the exhaust gas of the fuel cell 10 with an exhaust gas of a combustion chamber 56 according to a directional arrow 58 acted upon. This combustion chamber 56 is again hydrogen from the tank 22 via a valve 60 and at least a portion of the sucked and compressed air can be supplied.

In the combustion chamber 56 Then, a combustion of the hydrogen-air mixture, wherein the resulting exhaust gas carries a relatively high energy in the form of heat energy, which is used to drive the turbine 46 can be used.

In the flow direction of both the exhaust gas of the fuel cell 10 as well as the exhaust gas of the combustion chamber 56 downstream of the turbine wheel 44 is an exhaust aftertreatment device 62 which cleans said exhaust gases before they are released to the environment. Furthermore, the powertrain includes 8th a control device 64 , by means of which the circulating-amount dosage 50 as well as the valves 24 and 60 be managed.

The rotors 31 and 39 the charging devices 28 and 41 are in the axial direction of the respective compressor wheel 32 and 40 and thus the rotors 31 and 39 according to directional arrows 70 respectively 72 by means of a bearing ring 66 ( 2 to 4 ) a storage device 68 ( 2 to 4 ) stored.

As with a synopsis of 2 to 4 becomes clear, includes the storage device 68 a thrust bearing 76 with the bearing ring 66 and according to the 2 and 3 with another bearing ring 67 , by means of which the rotor 31 . 39 in the axial direction of the compressor wheel 32 . 40 is stored.

aus dem mittleren Durchmesser D_ax und dem Austrittsdurchmesser D_V zumindest im Wesentlichen in einemThe bearing ring 66 has an inner diameter D _i ( 2 ) and an outer diameter D _a ( 2 ) on. The compressor wheel 32 . 40 has an exit diameter D _V ( 4 ) on. Forming the arithmetic mean of the inner diameter D _i and the outer diameter D _a , the result is a mean diameter D _ax ( 4 ) of storage 66 , where a quotient

from the mean diameter D _ax and the exit diameter D _V at least substantially in one

liegt. Diese Anordnung des Lagerrings 66 auf einem relativ großen Durchmesser wird bei einer gemäß der 1 gezeigten Versorgung der Brennstoffzelle 10 mit Luft durch einen relativ großen Durchmesser des Elektromotors 36 begünstigt, wobei der Elektromotor 36 einen drehfest mit der Welle verbundenen Elektromotorrotor 78 sowie einen fest mit einem Lagergehäuse 80 der Aufladeeinrichtung 28, 41 verbunden Elektromotorstator 82 umfasst. An einer Stirnseite 84 des Elektromotorrotors 78 ist eine sich mit dem Motorrotor 78 drehende Gleitscheibe 87 des Axiallagers 76 angeordnet, die zur Abstützung von Axialkräften mit dem Lagerring 66 zusammenwirkt. Somit ist ein aerodynamisches Axiallager 76 geschaffen, welches Axialkräfte effizient abstützt zur Darstellung einer hohen Lebensdauer der Lagerungseinrichtung 68 und damit der Aufladeeinrichtung 28, 41.Section

lies. This arrangement of the bearing ring 66 on a relatively large diameter is in accordance with the 1 shown supply of the fuel cell 10 with air through a relatively large diameter of the electric motor 36 favors, the electric motor 36 a rotatably connected to the shaft electric motor rotor 78 and one fixed to a bearing housing 80 the charging device 28 . 41 connected electric motor stator 82 includes. At one end 84 the electric motor rotor 78 is one with the motor rotor 78 rotating sliding disk 87 of the thrust bearing 76 arranged to support the axial forces with the bearing ring 66 interacts. Thus, an aerodynamic thrust bearing 76 created, which supports axial forces efficiently to represent a long life of the storage device 68 and thus the charging device 28 . 41 ,

The storage facility 68 is designed as an air bearing device, wherein the thrust bearing 76 is lubricated by air. One through the rotating compressor wheel 32 . 40 effected gas pressure force on a Verdichterradrücken 86 leads to an axial thrust of the rotor 31 . 39 according to a directional arrow 88 against an inflow according to a directional arrow 90 the air of the thrust bearing 76 which reacts with the air as a lubricant via defined feed channels 90 is available. The feeder channels 90 go through a wall in the axial direction according to the directional arrow 70 . 72 between the compressor wheel 32 . 40 and the electric motor rotor 78 ,

The storage facility 68 further includes a radial bearing 92 leading to the compressor wheel 32 . 40 through a maze 94 sealed and also supplied with air as a lubricant. The radial bearing 92 can also be provided by a ball bearing and / or a plain bearing with low bearing stress.

The front side 84 the electric motor rotor 78 forms together with a throughput behavior or Aufstauverhalten the bearing ring 66 also a partial compensation of an axial thrust due to the axial forces, whereby a through the bearing ring 66 illustrated air bearing undergoes relief.

The second bearing ring 67 for the axial bearing of the rotor 31 . 39 , which also with through the compressor wheel 32 . 40 compressed air is compressed and at the Verdichterradrücken 86 arranged and fixed to this ensures a defined position of the rotor 31 . 39 off without moving in the direction of the electric motor rotor 78 or the electric motor stator 82 larger bearing loads must be absorbed. Thus, also by the bearing ring 67 created an aerodynamic air bearing for supporting axial forces. The air as a lubricant, which absorbs the bearing loss in the form of heat, leaves the bearing housing 80 for example, via an annular gap between the electric motor rotor 78 and the electric motor stator 82 in the direction according to the directional arrow 90 and will eventually be released to the surrounding area.

The charging device 28 . 41 according to 2 further comprises a radial wedge blade diffuser 96 and an axial cone diffuser 98 , The from the compressor wheel 32 . 40 air to be compressed flows according to a directional arrow 100 in a compressor housing 102 of the compressor 30 . 38 , is from the compressor wheel 32 . 40 compacted and over a compressor spiral 104 from the compressor housing 102 discharged.

The 3 shows one of the 2 different supply of the bearing ring 66 as a lubricant to be supplied air, wherein a tapping point of the air in the compressor spiral 104 opens, and the pressure in the compressor spiral 104 due to a flow of air through both the axial Konusdiffusor 98 as well as through the radial wedge blade diffuser 96 at least almost a maximum discharge pressure of the compressor 30 . 38 equivalent. supply channels 90 to the air supply are through the compressor housing 102 , through the radial wedge blade diffuser 96 and the corresponding wall of the bearing housing 80 guided and in an area of the bearing ring 66 , which also represents a sliding disk, and the sliding disk 87 guided. To represent a desired load capacity of the thrust bearing 76 and in particular the interaction of the bearing ring 66 with the sliding washer 87 It is advantageous to the bearing ring 66 and optionally the sliding disk 87 by means of laser drilling or deliberately porous, possibly by powder metallurgy by sintering, make correspondingly permeable to air. This is in particular an annular region in the radial direction of the bearing ring 66 according to the directional arrow 74 Air can flow through between the inner diameter D _i and the outer diameter D _a .

The 4 shows the thrust bearing 76 for the charging device 28 . 41 , which is designed as a so-called freewheeler, such as, for example, as a charging device 28 is used or could be suitable for an exhaust gas turbocharger. The bearing rings designed as sliding disks 66 and 67 , which also according to the 2 and 3 are designed as sliding disks are in the axial direction according to the directional arrow 70 . 72 of the rotor 31 . 39 on both sides of a rotation with the shaft 34 . 42 connected disc 106 arranged and act with corresponding sliding discs 87 together, on the disc 106 are arranged and fixed with this, which in turn aerodynamic air bearings for axial mounting of the rotor 31 . 39 are shown.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 8717441 U1 [0003]

Claims (9)

Charger ( 28 . 41 ) for compressing a medium, in particular air, with at least one compressor wheel ( 32 . 40 ) comprehensive rotor ( 31 . 39 ), which by means of at least one an inner diameter (D _i ) and an outer diameter (D _a ) having bearing ring ( 66 . 67 ) a storage device ( 68 ) in the axial direction ( 70 . 72 ) of the compressor wheel ( 30 . 40 ), characterized in that a quotient

from a mean diameter D _{ax of} the bearing ring formed from the arithmetic mean of the outer diameter (D _a ) and the inner diameter (D _i ) ( 66 ) and an outlet diameter D _{V of} the compressor wheel ( 30 . 40 ) at least substantially in a range of

lies. Charger ( 28 . 41 ) according to claim 1, characterized in that the at least one bearing ring ( 66 ) is lubricated by means of a lubricant supply device with at least substantially liquid lubricant. Charger ( 28 . 41 ) according to one of claims 1 or 2, characterized in that the storage device ( 68 ) is at least partially formed as an air bearing device, wherein the at least one bearing ring ( 66 . 67 ) is associated with the air storage device. Charger ( 28 . 41 ) according to claim 3, characterized in that the storage ring ( 66 . 67 ) Air via at least one air duct ( 90 ) can be fed. Charger ( 28 . 41 ) according to claim 4, characterized in that the at least one air duct ( 90 ) in the region of a Radrücken ( 86 ) of the compressor wheel ( 30 . 40 ) is arranged. Charger ( 28 . 41 ) according to one of the preceding claims, characterized in that the bearing ring ( 66 . 67 ) in a ring region in the radial direction ( 74 ) of the bearing ring ( 66 . 67 ) is at least partially permeable to air between the inner diameter (D _i ) and the outer diameter (D _a ). Charger ( 28 . 41 ) according to one of claims 4 or 5, characterized in that the at least one air duct ( 90 ) into a spiral channel ( 104 ) of the charging device ( 28 . 41 ) opens. Charger ( 28 . 41 ) according to one of the preceding claims, characterized in that at least one second bearing ring ( 66 . 67 ) is provided, wherein by means of the first bearing ring ( 66 ) Axial forces in a first, at least substantially parallel to the axial direction ( 70 . 72 ) extending direction and by means of the second bearing ring ( 67 ) Axialkräfte in a second, opposite to the first direction extending direction are accommodated. Drive train for a motor vehicle with at least one charging device ( 28 . 41 ) according to any one of the preceding claims.

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