EP1319842A1 - Rotor or rotating element for turbocompressor - Google Patents

Abstract

The turbocharger rotor (100) which constitutes the support for a rotor stage (3,3') comprises at least two individual crown wheels (20,21,22) comprising at their periphery half sections (110,110'111,111') which, during the juxtaposition of the crown wheels, make a complete groove (10) in which the feet (80,80') of the movable blades (70,70') are engaged.

Description

Subject of the invention

The present invention relates to compressors, especially for turbochargers.

It relates more particularly to turbocharger rotors.

State of the art

Turbochargers are well known in the state of the art and are used in particular for double body engines, turbofans and turbojets.

These turbochargers, which can be low pressure type or high pressure type, are, essentially consisting of a succession of floors rotor blades moving alternately with stages stator of fixed blades (also called stages rectifiers).

In the case of low pressure compressors, the blades of the different successive rotor stages of the compressors are fixed on a single element rotor or rotor. At the periphery of said rotor are machined a succession of grooves which allow the embedding of the feet of the moving blades of the different rotor stages.

In the event that a rotor is common to several rotor stages, for example three or four, this rotor will include, arranged at its periphery, several annular grooves.

More specifically, the rotor will therefore include, arranged in a first radius in a circular manner, a first groove in which a first will be placed series of movable blades so as to constitute a first rotor stage.

The rotor will then include, arranged at a certain distance from the first groove (which corresponds to the width of a rectifier stage), a second groove in which will be arranged a second series of movable blades of so as to constitute a second rotor stage, and so after.

However, to allow the embedding of feet of the series of movable blades in the annular groove, the latter is provided with at least one notch or radial opening which allows successive insertion of feet of the series of movable blades.

After placing the last dawn of the series, suitable locking means such as locks are used to block the foot of this last moving dawn. These blocking means allow also to avoid any displacement of the feet of the series movable blades within the annular groove.

This design of known rotors is expensive and complex to carry out. In addition, the openings or notches pierced in the bottom of the grooves weaken particularly the rotor, which of course constitutes a additional disadvantage.

Finally, the blocking means, and in especially locks, used to immobilize blades in the corresponding grooves cause disturbances in the aerodynamic vein of the fluid, which generates pressure losses and harmful vibrations correct operation of the turbocharger.

A final, very significant drawback of the presence of such blocking devices resides in the ovalization of the rotor after a certain period of operation.

Aims of the invention

The present invention aims to remedy the disadvantages stated above of rotors of known turbochargers, providing a rotor of new design intended more particularly for a low pressure compressor and in which the fixing of movable blades in the rotor grooves is simplified and does not no longer requires the use of blocking elements such as locks, disturbance generators.

Main characteristic features of the invention

The present invention relates to a rotor or rotor element for a turbocharger, constituting supporting at least one rotor stage of movable blades, in which at least one groove is provided to allow the engagement of the feet of a series of movable blades, characterized in that said rotor or rotor element includes at least two individual crowns comprising at their lateral periphery of the half-profiles which, when juxtaposition of individual crowns, make a full throat in which the feet of a series of moving blades. Each gorge is delimited by lips or edges.

Half-profile means a shape which laterally delimits said crown and which makes it possible to recreate a full throat with or without bottom when two crowns are docked or juxtaposed successive.

This profile could be formed by the juxtaposition of two half-cells (1/2 per crown juxtaposed) or two half-grooves or simply be under flat shape.

According to a first embodiment, the invention relates to a rotor or rotor element for turbocharger with a single rotor stage with a single series of movable blades.

According to this preferred embodiment, the ferrule is essentially annular and is formed by two annular crowns which are juxtaposed. Half-profiles are arranged laterally at the periphery of each of the crowns, so that the half-profiles of a crown are located opposite the half-profiles of the consecutive crown to reconstruct the throat intended for receive the feet of the series of movable blades of the stage rotor.

To assemble the blades on the rotor, it it is therefore sufficient to separate the two crowns to open the throat, then to engage the feet of the blades in the half-profiles one of the crowns, then juxtapose the two crowns to close the half-profiles constituting the groove and trap the feet of a series of movable blades successive. The two crowns are then secured by own means.

Advantageously, the fixing of the two rotor crowns can be made by any known means suitable and is preferably made removable. In this effect, it can for example be produced by welding, at by means of rivets or by means of screws.

According to the invention, however, it is preferred to make use of a means of fixing the crowns, which is removable. The use of a removable fixing means presents the advantage of allowing the replacement of a dawn deteriorated for example.

To this end, in one embodiment advantageous of the invention, the two consecutive crowns are removably attached to each other by a assembly of bolts and nuts passing through flanges integral with said crowns.

According to the present invention, the half-profiles of the crown have a shape such that the throat formed by the juxtaposition of the two half-profiles will present a shape complementary to the profile of the feet of the series of movable blades that will be embedded or engaged in said throat.

According to another embodiment, the half-profiles of the crown have the shape of a half-cell, so that the groove formed by the juxtaposition of the two half-profiles has a dovetail profile which will correspond to the profile of the so-called feet of the series of movable blades which will be embedded or engaged in said throat.

Alternatively, the half-profiles of the crowns have a flat shape so that the groove formed by the juxtaposition of the two half-profiles present a groove which allows the straight feet or planes of the series of movable blades to be enshrined there.

Immobilization of the series of movable blades within a throat can then advantageously be obtained by any suitable means, for example at using a locking screw passing through the rotor.

According to the other embodiment, the present invention relates to a rotor for a turbocharger comprising a succession of rotor stages, the rotor being common in this case multi-storey with multiple moving blade series. In the particular case of a compressor with a common two-stage rotor rotor, the turbocharger includes two series movable blades and the rotor comprises a crown intermediate and two end rings. The crown intermediate present on each of its faces half-profiles which correspond to the half-profiles present on each of the end rings so that reconstitute during assembly the two complete grooves for embedding the two sets of movable blades of two successive rotor stages.

The generalization of this principle to several rotor stages (three, four or five) can of course be easily understood by those skilled in the art.

The invention also relates to a turbocharger comprising a stator and a conforming rotor to the invention, as defined above.

In the turbocharger according to the invention, the stator comprises one or more stages of fixed blades, alternating with the stages of rotating blades of the rotor.

The turbocharger according to the invention can for example being a turbofan, a turbojet or a gas turbine coupled to an alternator for the electricity production.

The invention has multiple advantages, both with regard to the construction of the rotors and the operation of turbochargers. On the one hand, the rotor construction is simpler and more economical because it no longer requires expensive machining of grooves complete nor that of corresponding blade supports. On the other hand, it removes the need to practice side openings through the rotor for the passage of blades, which simplifies the construction of the rotor and avoids the presence of high stress areas in the rotor. Born requiring more blade retainer locks on the rotor, the invention has the additional advantage of reduce the pressure losses in the fluid flow, reduce vibrations in turbochargers and especially to reduce or eliminate the ovalization of the rotor by operation. All other things being equal by elsewhere, it thus has the advantage of improving the performance of turbochargers and reduce mechanical stresses to which they are subjected.

Brief description of the figures

Figure 1 shows a general view of a classic turbocharger.

Figure 2 is a cross-sectional view of a part of a rotor according to the state of the art.

Figure 3 is an exploded view, in elevation, of a part of a rotor showing the elements of blocking constituted by locks used to fix the last dawn in a gorge according to the state of the art.

Figure 4 is a cross-sectional view of a rotor according to an embodiment which combines two forms particular execution of the present invention.

Description of a preferred embodiment of the invention

In these figures, the same notations of reference designate identical elements.

As illustrated in Figure 1, the floor of compression of a turbofan is composed of a series of stages rotor 3.3 ', 3 ", ... alternating with a series of stages stator or rectifiers 2,2 '/ 2 ", ...

In Fig. 1, for each floor, only shows in section that the first blade 70, 70 ', 70 "for each rotor stage or 60, 60 ', 60 "for each stage rectifier or stator.

Indeed, while each rotor stage 3.3 ', 3 ", ... includes a series of movable blades 70,71,72, ... , each rectifier or stator stage 2,2 ', 2 ", ... includes a series of fixed vanes respectively 60,61,62 ...

Each rectifier stage 2,2 ', 2 ", ... includes in addition an inner ferrule respectively 4.4 ', 4 ", ... connected to an outer shroud respectively 5.5 ', 5 ", ... by the series of fixed vanes respectively 60,61,62, ...; 60 ', 61', 62 ', ... or 60 ", 61", 62 ", ... Said ferrules interior 4,4 ', 4 ", ... and said exterior ferrules 5.5 ', 5 ", ... are therefore specific to each of the floors 2.2 ', 2 "rectifiers, ...

Several series are attached to rotor 100 movable vanes, respectively 70,71,72; 70 ', 71', 72 ', ... constituting as many rotor stages 3.3 ′, 3 ", ... We have therefore for all rotor stages 3.3 ′, 3 ″ one and same rotor 100 at the periphery of which are dug grooves 10,10 ', 10 ".

Such a rotor is shown in Figs. 2 and 3 according to the technological background. It corresponds to a monobloc annular rotor 100, fixed transversely to a disc 15 (intended for example to be coupled to a motor). The rotor 100 is generally made of titanium. The throats 10,10 ', 10 "are machined at its periphery and correspond each with a rotor stage 3,3 ', 3 ". The grooves 10,10', 10" are intended to receive the feet 80,81,82, ...; 80 ', 81', 82 ', ... and 80 ", 81", 82 ", ... series successive blades 70,71,72, ...; 70 ', 71', 72 ', ... and 70 ", 71", 72 ", ...

When the turbofan is running, the gas first crosses the first rectifier stage 2 of the compressor where its speed vector is repositioned so to be driven by the second rotor rotor stage turning 3 'before reaching the second floor rectifier 2 'to be repositioned again in 3 ", etc. The gas thus undergoes a training cycle repositioning at the end of which its kinetic energy gradually decreases as its pressure increases.

Fig. 3 represents a groove 10 in which are successively set the feet 80,81,82, ... 89 of the moving blades 70,71,72, ... 79 of only one rotor stage.

For this purpose, side openings 14 are practiced in said groove 10. After the introduction of the last blade 79, this is fixed with one or more than one locking element 30.32.

The rotor shown in FIG. 4 complies to the present invention. It represents a view of mind in which two rotor stages are shown.

The first rotor stage 3 is constituted of a series of movable vanes 70, 71, ... all similar and with a foot 80.81, ... in the form of a dovetail, while the second rotor stage 3 'has blades 70 ', 71', ... all similar and having a foot 80 ', 81', ... straight or flat.

As a result, as shown in the figure, the grooves 10 and 10 'intended to receive the feet first and second stages 3 and 3 'are shaped different way.

In practice, however, one must understand that we will have one and the same profile for the various grooves intended to make the different floors rotor.

According to the present invention, the rotor 100 is made up of at least two crowns, and in this case three crowns 20, 21 and 22 intended to achieve the inner ferrule of the different rotor stages 3.3 ′.

According to the example of execution described in the Fig. 4, the intermediate crown 21 present on each from its lateral faces an annular half-profile, while the end rings 20 and 22 present on a single of their two lateral faces an annular half-profile corresponding to that placed opposite on the crown which it is jusxtaposed. The juxtaposition of these half-profiles will make a full groove 10,10 ' allowing the insertion of the feet 80,81, ... or 80 ', 81', ... series of blades 70, 71, ... or 70 ', 71', ...

After placing said feet of said blades in the corresponding grooves, the crowns 20,21,22 are joined to each other so as to form the rotor 100 completely.

The fixing of the various crowns is carried out using any suitable means.

In the figure shown, we propose make flanges 115,115 ', 116,116' in which is provided an opening through which passes a rod-bolt-nut assembly.

Concretely, to fix the different sets of movable blades, it suffices to separate the various crowns 20,21,22, to spread them apart to open the grooves 10,10 ', ..., to insert each series of feet 80,81,82, ... movable blades 70,71,72, ... in between crowns and then move closer and juxtapose again the crowns 20,21 so as to trap and immobilizing said feet in the respective grooves.

Note that the profiles of the grooves and therefore the half-profiles constituting them can take forms various and other than those mentioned in the two preferred execution examples. These profiles can be dovetail shape, circular or polygonal. Likewise, the feet of the movable blades can also be shaped dovetail, circular or polygonal, provided that the profile of said feet of said movable blades is complementary and corresponds to that of said grooves.

Claims (7)

Rotor (100) or rotor element for a turbocharger, constituting the support for at least one rotor stage (3,3 ') comprising a series of movable blades (70,71,72, ...; 70', 71 ', 72 ', ...), in which is provided at least one groove (10,10') to allow engagement of the feet (80,81,82, ...; 80 ', 81', 82 ', .. .) of a series of movable blades, characterized in that said rotor (100) or rotor element comprises at least two individual rings (20,21,22, ...) comprising at their lateral periphery half-profiles ( 110,110 ';111,111'; ...) which, when the individual crowns are juxtaposed, make a complete groove (10,10 ') in which the feet (80,81,82, ...; 80', 81 ', 82', ...) of the series of movable blades (70,71,72, ...; 70 ', 71', 72 ', ...). Rotor or rotor element according to claim 1, characterized in that the two consecutive rings (20,21,22) are fixed to each other in a removable or irremovable manner. Rotor or rotor element according to claim 2, characterized in that the two consecutive rings (20,21,22) are fixed to each other by an assembly of bolts and nuts (13,13 ') passing through flanges (115,115 ';116,116') integral with the crowns (20,21,22). Rotor or rotor element according to any one of claims 1 to 3, characterized in that the groove (10,10 '), when reconstituted, has a dovetail shape, circular, polygonal or planar, in which feet (80,81,82, ...; 80 ', 81', 82 ', ...) of complementary shape to the series of movable blades (70,71,72, ...; 70' , 71 ', 72', ...) are nested or engaged. Turbocharger comprising a rotor and a stator, characterized in that the rotor conforms to any one of claims 1 to 4. Turbocharger according to claim 5, characterized in that it is a turbofan. Turbocharger according to claim 6, characterized in that it is a turbojet.

Images