RU2549002C1 - Turbine compressor with gas magnetic bearings - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: turbine compressor with gas magnetic bearings contains a rotor with compressor impeller. The compressor drive is turbine running on spent gases of internal-combustion engine, and cylindrical rotor is located on two support-thrust gas magnetic bearings. In each gas magnetic bearing the ring active electromagnet and two active radial electromagnets are installed to accept axial and radial forces respectively by interaction with the shaft, turbine impeller and ring insert of the compressor impeller out of the ferromagnetic material. In gas magnetic bearings the feeders are made to supply in axial and radial direction of the compressed air supplied from the discharge main line of the compressor.

EFFECT: invention ensures possibility of adjustment of the bearing carrying ability, increases efficiency of rotor oscillations dampening, and simplifies system of ail lubrication supply to bearings.

2 dwg

Description

The invention relates to the field of engineering, and specifically to turbochargers used in pressurization systems of automobile, diesel, marine and other types of internal combustion engines (ICE).

Known turbochargers with the following types of contactless bearings that provide minimal friction losses: gas, magnetic and gas-magnetic (conical shape).

Known turbocharger with a bearing assembly on gas lubricant, which is a floating mono-sleeve with supply holes [1]. The mono-bush design provides compensation for radial and axial movements. To exhaust the exhaust air, the rotor shaft is hollow, and the turbine impeller has axial drilling.

Known turbocharger with gas-static bearings [2]. The turbocharger rotor consists of a turbine wheel, on the same shaft with which compressor wheels are located on both sides. Between the turbine and the corresponding compressor wheel there is a gas-static bearing, which is both support and thrust. At the ends of the shaft, rolling bearings with elastic damper bearings are installed.

Known turbocharger with gas-static supports [3]. The design feature of the bearings is that the gas-static bearings are located between the impeller of the compressor or turbine and the corresponding section of the compressor or turbine housing.

The disadvantages of these designs of bearing assemblies is the relatively low bearing capacity of the gas layer, which, when vibrations occur on a running engine, can lead to loss of stability. You can also note the complexity of the design of the bearing assembly and some other elements. In the case of a mono-bush, this is the use of structural solutions to provide an external lubricating gas layer (between the bearing and the housing), the execution of the rotor shaft hollow and the turbine impeller with drilling. In the case of the second design, this is the use of safety rolling bearings at the ends of the shaft. In the third turbocharger, the design of the impellers of the turbine and compressor, as well as the corresponding parts of the housings, is complicated, which complicates the manufacturing technology of the parts.

Known turbomachine with magnetic bearings [4]. In the design of the turbomachine, radial and axial active magnetic bearings are used to support the rotor. The disadvantage of a turbomachine is the relatively low bearing capacity of the bearings, characteristic not only of gas, but also of magnetic bearings, and the presence of safety rolling bearings, which complicates the design of the entire device.

In general, the disadvantages of the gas and magnetic supports of turbochargers can be summarized as follows. Both gas and magnetic bearings have a relatively low bearing capacity and a tendency to loss of stability when vibration occurs, which is inevitable with a running engine. Magnetic bearings, and sometimes gas bearings, are insured by rolling or plain bearings in case of failure, which leads to a design complication. Also in a magnetic field, a suspended body is in an unstable position.

Nevertheless, the use of non-contact bearings with low friction losses in turbochargers is promising. The solution to improve the characteristics of contactless bearings and partially eliminate their disadvantages is the use of combined bearings - gas-magnetic bearings. Such bearings have a greater bearing capacity, better dampen vibrations and stabilize the rotation of the rotor. At the same time, safety bearings can be abandoned, since gas lubrication will be insurance for the magnetic bearing.

Known turbocharger with electric drive and gas conical support [5]. The turbocompressor rotor consists of a compressor impeller, a conical support facing with a smaller diameter towards the compressor, two wheels for pumping gas lubricant into the working gap and removing it from the gap. The gas-magnetic suspension of the rotor is provided by the combined action of the lifting forces of the gas lubricant layer and the electromagnetic forces of attraction of the rotor to the stator.

A feature of the last turbocharger is that the design does not have a turbine wheel to drive the compressor, which actually turns the turbocharger into an electric compressor, and the shaft in the middle has a conical section, which complicates the manufacturing technology. At the same time, the design of the rotor of the vast majority of produced ICE turbocompressors includes a cylindrical shaft, compressor and turbine wheels. The tapered bearing also provides axial forces compensation in only one direction, while in turbochargers operating on ICE exhaust gases, axial forces can occur in two directions due to gas flow pulsation.

The turbocharger described above is the closest analogue of the claimed invention on the principle of maintaining the rotor. The constructive solution proposed below allows, using the very idea of combining gas and magnetic forces, set forth in [5], to apply it to industrial designs of turbocompressors operating on ICE exhaust gases.

The main objective of the invention is to improve the turbocharger by changing the design of the bearing assembly, which allows applying the gas-magnetic principle of maintaining the rotor for industrial designs of turbochargers with a cylindrical rotor and a gas turbine drive while simplifying the compressed air supply to the bearings.

To solve this problem, a turbocompressor with gas-magnetic bearings is proposed, containing a rotor with a compressor impeller. The compressor is driven by an ICE exhaust gas turbine, and the cylindrical rotor is housed in two thrust gas-magnetic bearings, each of which has an annular active electromagnet and two active radial electromagnets to absorb axial and radial forces, respectively, by interacting with the shaft and turbine wheel and an annular insert of a compressor wheel of ferromagnetic material. In gas-magnetic bearings, feeders are made for supplying in the axial and radial direction of compressed air supplied from the compressor discharge line.

Effect: the ability to perceive the axial forces of the rotor in two directions, regulate the bearing capacity of the bearings, effectively damp the oscillations of the rotor and simplify the system for supplying air lubrication to the bearings.

A structural diagram of a turbocharger with gas-magnetic bearings is shown in FIG. 1, the arrangement of radial electromagnets in the bearing - in FIG. 2:

1 - the impeller of the compressor;

2 - insert of ferromagnetic material;

3 - sleeve;

4 - bearing housing;

5 - thrust bearing;

6 - turbine impeller;

7 - feeding holes;

8 - radial electromagnet;

9 - axial electromagnet;

10 - shaft;

11 - camera.

The turbocharger consists of a compressor housing and a turbine housing (not shown), a bearing housing 4 and a rotor. The rotor consists of a compressor impeller 1, a turbine impeller 6, and a shaft 10. The rotor shaft is housed in two thrust bearings 5. An annular electromagnet 9 is placed in each gas-magnetic bearing to compensate for axial forces and two radial electromagnets 8 are used to compensate for radial forces. Electromagnets 8 and 9 are of the type of active magnets (their control system is not shown). The magnetic field is created by the interaction of the electromagnets 8 and 9 with the shaft 10 and the impeller of the turbine 6, made of ferromagnetic material, and the impeller of the compressor 1, having an annular ferromagnetic insert 2. Gas-magnetic bearings also have feeding holes 7 (at least 4 in one row around the circumference) for supplying compressed air to the working clearance between the bearing and the rotor. Gas-magnetic bearings are placed in the sleeve 3, which, in turn, is located in the bearing housing 4. In the upper part of the bearing housing 4 there is an opening and a channel for supplying compressed air from the compressor discharge pipe through drilling in the sleeve 3, first to the chambers 11, and then through feed holes 7 into the working gap. At the bottom of the bearing housing there is an opening for exhaust air to the atmosphere. Part of the air may flow into the flow parts of the compressor and turbine.

The turbocharger operates as follows. Before starting, the electromagnets 8 and 9 of the bearings are supplied with power. In this case, the rotor shaft “pops up”. After the supply of the working fluid (for example, combustion products of the internal combustion engine) to the turbine wheel 6, the turbocharger rotor begins to spin. Part of the compressed air after the compressor is taken and fed into the bearing housing 4. Then, through the channels, the compressed air enters first into the chambers 11, then through the supply holes 7 to the working clearance between the rotor and the bearings, forming a gas lubricating layer. The support of the rotor in the bearings is ensured by the combined action of the pressure forces of the gas lubricating layer and the magnetic forces of attraction of the rotor to the bearings. Since the electromagnets included in the gas-magnetic bearing are of the type of active magnets, this allows you to adjust the bearing capacity of the bearing and more effectively damp rotor vibrations. Compared to the device [5], the air supply system is simplified, since there are no wheels for pumping and discharging gas lubrication and a pneumatic switch.

Information sources

1. Automobile engines with turbocharging / N.S. Khanin, E.V. Aboltin, B.F. Lyamtsev et al. - M.: Mechanical Engineering, 1991. - 336 p.

2. Patent No. 2171772 of the Russian Federation, IPC F01D 25/24, F02C 7/06; publ. 08/20/1998.

3. Patent No. 21118716 of the Russian Federation, IPC F04D 29/04; publ. 09/10/1998.

4. Patent No. 2386048 of the Russian Federation, IPC F02C 7/06; publ. 04/10/2010.

5. Copyright certificate No. 1746069 USSR IPC F04D 25/06; publ. 07/07/92, bull. Number 25.

Claims (1)

A turbocharger with gas-magnetic bearings, comprising a rotor with an impeller of the compressor, characterized in that the compressor is driven by a turbine that runs on the exhaust gases of the internal combustion engine, and the cylindrical rotor is housed in two support-thrust gas-magnetic bearings, each of which has an annular active electromagnet and two active radial electromagnets for the perception of axial and radial forces, respectively, by interacting with a shaft, a turbine wheel and an annular insert of a compressor wheel made of a ferromagnet deleterious material, the bearings are made in gasmagnetic feeders for feeding in the axial and radial direction of the compressed air supplied from the compressor discharge line.

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