This application claims priority to German Patent Application No. 10 2014 206 159.8, filed Apr. 1, 2014, and German Patent Application No. 10 2015 202 558.6, filed Feb. 12, 2015, both of which are hereby incorporated by reference in their entirety.
The present invention relates to a rotor of a supercharging device, in particular of an exhaust gas turbocharger. The invention additionally relates to a supercharging device having such a rotor.
From DE 10 2012 202 272 A1 a generic rotor of a supercharging device with a compressor wheel and a turbine wheel fastened thereon is known. Between the compressor wheel and the turbine wheel a heat shield is arranged, which subdivides a hollow space that exists between the compressor wheel and the turbine wheel into two hollow spaces. In these two hollow spaces a sub-pressure, in particular a vacuum, is provided, so that the turbine wheel solely because of the vacuum is held on the compressor wheel by way of the heat shield.
From DE 10 2008 048 135 A1 an exhaust gas turbocharger is known, which comprises a particular rotor geometry which is designed in such a manner that vibrations excited by the rotor are in a sub-critical frequency range. This serves to achieve that resonances do not become problematic up to the strength limit of the rotor.
Generally, a rotor of a supercharging device, for example of an exhaust gas turbocharger, usually consists of a compressor wheel, a shaft and a turbine wheel. This applies in particular to such embodiments in which the rotor via the shaft is located in a bearing housing that is located between a turbine housing respectively a compressor housing. A connection between the turbine wheel respectively the compressor wheel and the shaft is often effected by means of welding, which is advantageous in particular in the case of thin shafts. In the case of thicker shafts or in the case of a compressor wheel arranged directly on the turbine wheel welding however is not possible or only to a limited extent. For this reason, fastening of the turbine wheel to the compressor wheel by means of sub-pressure is recommended for example in DE 10 2012 202 272 A1. Disadvantageous with such an embodiment however is that with a diminishing sub-pressure there is the risk of the turbine wheel detaching from the compressor wheel and thus the risk of the rotor breaking apart, which because of the high rotational speeds of the rotor often results in a total destruction of the supercharging device.
The present invention therefore deals with the problem of stating an improved or at least an alternative embodiment for a rotor of the generic type, which ensures a reliable connection between turbine wheel and compressor wheel.
According to the invention, this problem is solved through the subject of the independent claims. Advantageous embodiments are subject of the dependent claims.
The present invention is based on the general idea of fastening a turbine wheel of a rotor to a compressor wheel of the rotor indirectly via a sealing disc, wherein the compressor wheel and the turbine wheel each have a holding contour and the sealing disc a counter-holding contour designed complementarily thereto, or vice versa. Alternatively to this it can also be provided that the sealing disc comprises a central counter-holding contour and located opposite a central holding contour and the compressor wheel and the turbine wheel in each case have a holding contour or a counter-holding contour that is designed complementarily thereto. Both embodiments have in common that the holding contour and the counter-holding contour in the assembled state engage in one another and in addition fasten the compressor wheel, the sealing disc and the turbine wheel to one another. Here, the holding contour is designed as a recess, whereas the counter-holding contour is designed as an extension designed complementarily thereto, or vice versa.
Practically, the compressor wheel and the turbine wheel comprise central recesses each facing one another. The sealing disc in turn comprises two extensions located axially opposite and projecting centrally, so that with its extensions it engages in the central recess of the compressor wheel and of the turbine wheel and thereby fastens these to one another. Alternatively to this it is conversely also conceivable that the compressor wheel and the turbine wheel each comprise central extensions facing one another, wherein in this case the sealing disc arranged between the compressor wheel and the turbine wheel has two central recesses located axially opposite. By the compressor wheel and the turbine wheel engaging with its central extensions in the central recesses of the sealing disc fastening of the components to one another can be likewise achieved—exact conversely in this case. The central recesses and the associated central axial extensions in this case do not only offer the possibility of an optimised connection of the individual parts to one another, in particular in the case of thicker shafts, but also a centring function at the same time. The embodiment described as second alternative additionally offers the major advantage that the extension on the turbine wheel heats up during the operation of the exhaust gas turbocharger and thereby expands which leads to a clamping and additional fixing in the recess of the sealing disc.
Again, alternatively, it can be provided that the sealing disc comprises a central extension and a central recess and that the compressor wheel comprises a recess that is designed complementarily thereto or an extension that is designed complementarily thereto and the turbine wheel comprises a recess that is designed complementarily thereto or an extension that is designed complementarily thereto and are thereby fastened to one another. Particularly favourable in this case is the alternative in which on the turbine wheel an extension and on the sealing disc an associated recess and on the compressor wheel a recess and located opposite on the sealing disc an associated extension are formed, since the extension on the turbine wheel heats up during the operation of the exhaust gas turbocharger and expands because of this which leads to a clamping and additional fixing in the recess of the sealing disc and simultaneously transfers the heat to the sealing disc and the extension facing the compressor wheel of said sealing disc, so that said extension can brace itself in the recess on the compressor wheel.
With an advantageous further development of the solution according to the invention, the extensions of the sealing disc comprise an external thread and the associated recesses in the compressor wheel or the turbine wheel have an internal thread designed complementarily thereto, so that the compressor wheel via the sealing disc can be screwed to the turbine wheel. Because of this a comparatively simple assembly of the rotor according to the invention can be achieved, wherein via the thread connection, i.e. the screw connection of the sealing disc both to the compressor wheel and also to the turbine wheel a reliable and durable connection can be created. A major advantage with this type of connection furthermore is that the same can be disconnected again for example for maintenance purposes. Analogously, the extensions comprising the external thread can also be arranged on the compressor wheel and/or on the turbine wheel and the associated internal threads on the sealing disc. It is also conceivable that on the turbine wheel an extension with external thread is provided, which can be screwed into an internal thread on the sealing disc, wherein on the side of the sealing disc facing the compressor wheel an extension comprising an external thread is provided, which can be screwed into an internal thread on the compressor wheel.
In a further alternative embodiment of the solution according to the invention, the extensions of the sealing disc are designed crowned or comprise a ball joint head, and thereby engage in the recesses of the compressor wheel respectively of the turbine wheel designed complementarily thereto. Because of this a connection in the manner of an articulated snap connection is possible, wherein in the recess on the turbine wheel respectively on the compressor wheel an undercut contour corresponding to the extension is provided. Assembling the rotor in this case is simply effected by pressing the respective extension into the associated recess on the compressor wheel respectively on the turbine wheel until the ball head or the extension of crowned design engages in the undercut contour on the turbine wheel respectively on the compressor wheel. In the same simple manner, the rotor, i.e. the individual parts of the same, can also be again detached from one another.
With a further advantageous alternative of the solution according to the invention, the extensions of the sealing disc are pressed into the associated recesses of the compressor wheel respectively of the turbine wheel or vice versa. Here it is conceivable that the extension with oversize is pressed into the respective recess, in particular of the compressor wheel respectively of the turbine wheel and the fixed connection between sealing disc and compressor wheel respectively turbine wheel established.
Obviously, a combination of individual connection possibilities described in the previous paragraphs is also conceivable so that for example the sealing disc can be screwed to the compressor wheel and pressed together with the turbine wheel via an extension.
Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the associated figure description with the help of the drawings.
It is to be understood that the features mentioned above and still to be explained in the following cannot only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention.
Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein same reference characters relate to same or similar or functionally same components.
Here it shows, in each case schematically,
According to the
Independently of the selected embodiment, the holding contour 13 is designed as a central recess 7, 7′, 7″, 7′″, whereas the counter-holding contour 14 is designed as a centrally projecting extension 6, 6′, 6″, 6′″.
According to
Looking at the embodiment of
Looking at the embodiment of
Here, the extensions 6, 6′, 6″, 6′″ can comprise an external thread 15 and the associated recess 7, 7′, 7″, 7′″ an internal thread 16 designed complementarily thereto, so that the compressor wheel 3 can be screwed to the turbine wheel 4 via the sealing disc 5, as is shown according to
Again alternatively, the extensions 6, 6′, 6″, 6′″ can also be formed with oversize to the associated recesses 7, 7′, 7″, 7′″ and are pressed into these. Here it is also conceivable purely theoretically that the extensions 6, 6′, 6″, 6′″ and the associated recesses 7, 7′, 7″, 7′″ do not have a rotation-symmetrical outer contour respectively inner contour but purely theoretically an angular outer contour or an angular contour that is formed complementarily thereto, as a result of which a torque transmission is possible in a particularly simple manner and in particular via a positively joined connection. Obviously it is also conceivable that the extension 6, 6″ has an external thread and the recess 7, 7″ an associated complementary internal thread, whereas the extension 6′, 6′″ has a ball joint head 8′, as a result of which a combination of the connections from
Looking further at the
On the whole, a connection of a turbine wheel 4 to a compressor wheel 3 can be achieved with the rotor 1 according to the invention even with a comparatively thick shaft 12, in particular provided a mounting of the shaft 12 on the end side is selected.
Number | Date | Country | Kind |
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10 2014 206 159 | Apr 2014 | DE | national |
10 2015 202 558 | Feb 2015 | DE | national |
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Number | Date | Country |
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1575700 | Dec 1970 | DE |
20009004 | Aug 2000 | DE |
102008048126 | Mar 2010 | DE |
102008048135 | Mar 2010 | DE |
102009014005 | Sep 2010 | DE |
102012202272 | Aug 2013 | DE |
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Entry |
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English abstract for DE-102008048135. |
English Abstract for DE-102008048126-A1. |
English Abstract for DE-102009014005-A1. |
Bibliographic Data Sheet Indicating No Abstract Available for DE-20009004-U1. |
German Search Report App. No. 102015202558.6 dated Oct. 14, 2015. |
Number | Date | Country | |
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20150275903 A1 | Oct 2015 | US |