BE1025131B1 - DOUBLE-CURVED TRANSMISSION SHAFT FOR TURBOMACHINE - Google Patents

Abstract

The invention relates to a one-piece element (30) of an axial turbomachine transmission shaft, generally hollow axisymmetric in shape and extending along its axis of symmetry (14) of a length greater than its mean diameter comprising a first spline set (40) for cooperating with a first axial junction (70) and a second set of splines (50) for cooperating with a second axial junction (72), the first and second sets of splines (40, 50). ) overlapping axially, at least partially. The invention also relates to a transmission shaft provided with such an element and a turbomachine equipped with such a shaft.

Description

(30) Priority data:

(73) Holder (s):

SAFRAN AERO BOOSTERS S.A.

4041, HERSTAL (MILMORT)

Belgium (72) Inventor (s):

PEETERS Maxime 4500 BEN-AHIN Belgium (54) DOUBLE-GROOVED TRANSMISSION SHAFT FOR TURBOMACHINE (57) The invention relates to a monobloc element (30) of an axial turbomachine transmission shaft, of generally hollow axisymmetric shape and s' extending along its axis of symmetry (14) of a length greater than its average diameter comprising a first set of grooves (40) intended to cooperate with a first axial junction (70) and a second set of grooves (50) intended to cooperate with a second axial junction (72), the first and second sets of grooves (40, 50) overlapping axially, at least partially. The invention also relates to a transmission shaft provided with such an element and a turbomachine equipped with such a shaft.

i

40.50

BELGIAN INVENTION PATENT

FPS Economy, SMEs, Middle Classes & Energy Publication number: 1025131 Deposit number: BE2017 / 5255 Intellectual Property Office International Classification: F01D 5/02 F16D 1/06 Date of issue: 11/14/2018

The Minister of the Economy,

Having regard to the Paris Convention of March 20, 1883 for the Protection of Industrial Property;

Considering the law of March 28, 1984 on patents for invention, article 22, for patent applications introduced before September 22, 2014;

Given Title 1 “Patents for invention” of Book XI of the Code of Economic Law, article XI.24, for patent applications introduced from September 22, 2014;

Having regard to the Royal Decree of 2 December 1986 relating to the request, the issue and the maintenance in force of invention patents, article 28;

Given the patent application received by the Intellectual Property Office on April 11, 2017.

Whereas for patent applications falling within the scope of Title 1, Book XI of the Code of Economic Law (hereinafter CDE), in accordance with article XI. 19, §4, paragraph 2, of the CDE, if the patent application has been the subject of a search report mentioning a lack of unity of invention within the meaning of the §ler of article XI.19 cited above and in the event that the applicant does not limit or file a divisional application in accordance with the results of the search report, the granted patent will be limited to the claims for which the search report has been drawn up.

Stopped :

First article. - It is issued to

SAFRAN AERO BOOSTERS S.A., Route de Liers 121, 4041 HERSTAL (MILMORT) Belgium;

represented by

LECOMTE Didier, P.O. Box 1623, 1016, LUXEMBOURG;

a Belgian invention patent with a duration of 20 years, subject to payment of the annual fees referred to in article XI.48, §1 of the Code of Economic Law, for: DOUBLE-GROOVED TRANSMISSION SHAFT FOR TURBOMACHINE.

INVENTOR (S):

PEETERS Maxime, Rue des Chevaux-Haleurs 7/32, 4500, BEN-AHIN;

PRIORITY (S):

DIVISION:

divided from the basic request:

filing date of the basic application:

Article 2. - This patent is granted without prior examination of the patentability of the invention, without guarantee of the merit of the invention or of the accuracy of the description thereof and at the risk and peril of the applicant (s) ( s).

Brussels, 11/14/2018,

By special delegation:

2017/5255

BE2017 / 5255

Description

DOUBLE-GROOVED TRANSMISSION SHAFT FOR TURBOMACHINE

Technical area

The invention relates to turbomachinery. The invention relates more particularly to an element constituting the transmission shaft and having splines for the transmission of the torque between the turbine and the compressor of a turbomachine. The invention also relates to the shaft provided with such an element and to an axial turbomachine, in particular an aircraft turbojet engine or an aircraft turboprop engine, provided with such a shaft.

Prior art

Document US2013 / 0323077 A1 discloses a compressor bell with external splines (54) and internal splines (52).

Document US 2007/084190 A1 describes a turbomachine transmission shaft. The shaft includes an assembly of several axisymmetric parts connected by grooves (Figure 3 of this document) to form a kinematic assembly driving the two series of counter-rotating blades of the fan. This kinematic assembly is bulky and complex to assemble / disassemble.

Documents US 2017/0116061 A1 and US 8,864,406 B2 describe coupling sleeves which have a double groove.

Summary of the invention

Technical problem

The object of the invention is to propose a transmission shaft element optimizing the compactness, the mass and the mechanical resistance.

The invention also aims to provide a simple, economical, reliable, easy to produce, convenient maintenance, easy inspection, and improving the performance of the turbomachine.

Technical solution

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The invention relates to a one-piece element of an axial turbomachine transmission shaft, of generally hollow axisymmetric shape and extending along its axis of symmetry of a length greater than its average diameter comprising a first set of grooves intended to cooperate with a first axial junction and a second set of splines intended to cooperate with a second axial junction characterized in that the first and the second set of splines overlap axially, at least partially.

By "axial overlap" is meant that each set of grooves comprises grooves which extend in the axial direction and the projection on the axis of the length of the grooves of the first set has at least two points in common with the projection on the axis of the length of the grooves of the second set. Another way of defining the axial overlap is to consider that there are at least two points on the axis which "see" radially the two sets of grooves. (When only one point of the axis sees the two sets of grooves, these do not overlap but are adjacent / contiguous. Other ways of expressing this overlap can be the expressions "axial superposition", since if we projects the two sets of grooves on the axis, the projections are at least partially superimposed, or speak of "radial superposition", since a given radius starting from the axis meets the two sets of grooves.

By “axial junction” is meant a substantially axisymmetric part able to be positioned along the same axis as the longitudinal axis of the monobloc element and in cooperation with one of its groove sets.

The axial length of the one-piece element can preferably be greater than 3, 5 or 10 times its average diameter.

The invention can also be defined as a one-piece axial section of an axial turbomachine transmission shaft, in particular a one-piece transmission shaft element, possibly of a turbojet engine, the section comprising a longitudinal axis, a first series of splines distributed around the axis

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BE2017 / 5255 longitudinal and a second series of grooves distributed around the longitudinal axis and overlapping the grooves of the first set of grooves.

According to a preferred embodiment of the invention, the one-piece element comprises an annular partition or tubular wall separating and / or radially connecting the first set of splines from the second set of splines. The partition is advantageously of constant radial thickness along the overlap of the grooves, and possibly all along the grooves.

According to an advantageous embodiment, the grooves of the first set are external, that is to say that they extend radially outward from the tubular wall and the grooves of the second set are internal, that is to say that is, they extend radially inward from the tubular wall. The external splines are capable of rotating a part with a diameter greater than the diameter of the tubular wall at the location of the splines. The internal splines are capable of rotating a part with a diameter less than the diameter of the tubular wall at the location of the splines.

According to an advantageous embodiment, the internal splines are larger radially and / or axially than the external splines. Thus a higher torque can be transmitted via the internal splines.

According to particular embodiments, the element can include one or more of the following characteristics, taken individually or according to all possible technical combinations:

- at least one or each set of grooves comprises at least: six, or ten, or sixteen, or twenty grooves;

- At least one or each set of grooves has grooves of radial height between: 1 mm and 20 mm, or between 3 mm and 10 mm;

- At least one or each set of grooves has grooves of axial length between: 10mm and 150mm, or between 20mm and 100mm;

- the grooves of the first set extending axially over at least 10%, or over the majority of the length of the grooves of the second set;

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- the grooves of one of the two sets of grooves extend axially in length beyond the other of the sets of grooves by at least 10%, preferably at least 20%, 30% or 50%;

- The axial length of a set of splines is between 50 and 100% of the length of the other set, preferably between 80 and 100%;

- the grooves are angularly offset, that is to say that the grooves of one of the groove sets are not radially aligned with the grooves of the other set;

- at least one of the sets includes irregular grooves to allow only a defined number of angular mounting position (polarizing) with the corresponding axial junction;

- the games are circular and / or continuous games.

Advantageously, the monobloc element comprises a connection end, the first set of splines and the second set of splines being formed on said connection end.

Advantageously, the monobloc element comprises a central axial section with a first mean diameter, and a second mean diameter where the grooves of the first set and of the second set overlap, the second mean diameter being greater than the first mean diameter, possibly d '' at least 30%.

Advantageously, the monobloc element comprises a third set of splines overlapping at least partially axially the first or the second set of splines.

Advantageously, the element comprises a third set of splines axially distant from the first and second sets. The first and second set of grooves are at one axial end of the element and the third set of grooves is located at the other axial end of the element.

According to an advantageous embodiment of the invention, the one-piece element has two generally cylindrical sections of different diameters, connected by a generally conical section.

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According to an advantageous embodiment of the invention, the three sets of grooves are carried by the same section, cylindrical or conical.

According to an advantageous embodiment of the invention, the one-piece element comprises a third cylindrical section at least partially concentric with the first section and the third set of splines is located on this third section.

According to an advantageous embodiment of the invention, the first and second sets of splines are located on one of the cylindrical sections, and the third set of splines is located on the other of the cylindrical sections or on the conical section.

According to an advantageous embodiment of the invention, the grooves of at least one of the sets are curved so that the circumferential curvilinear thickness of the groove between two successive grooves varies along the axis of the element. In other words, the grooves of at least one set include arcuate axial flanks. Thus, the grooves of at least one set have circumferential width reductions towards their axial ends.

According to an advantageous embodiment of the invention, at least one set of grooves has an annular envelope in the form of an ellipsoid or hyperboloid of revolution.

According to an advantageous embodiment of the invention, the element consists of maraging steel (martensitic aging steel).

According to an advantageous embodiment of the invention, the element is heat treated at least at the level of its grooves.

The invention can also be defined as a single-piece element of a turbomachine transmission shaft, the element comprising an annular row of internal axial grooves and an annular row of external axial grooves extending axially along the external axial grooves. The characteristics specific to the grooves can be transposed to the grooves.

The invention also relates to an axial turbomachine transmission shaft comprising at least one monobloc element as described above.

2017/5255 g BE2017 / 5255 and two one-piece axial junctions each engaging in one of the groove sets respectively.

Finally, the invention relates to a turbomachine, in particular an aircraft turbojet or turboprop engine comprising a blower, a low pressure turbine and a low pressure compressor, the turbomachine comprising a transmission shaft according to the invention, where one of the two axial junctions cooperate directly or indirectly with the blower; and / or one of the two axial junctions cooperates directly or indirectly with the low pressure turbine; and / or one of the two axial junctions cooperates directly or indirectly with the low pressure compressor.

According to an advantageous embodiment of the invention, the one-piece transmission shaft element is mounted in the casing of the turbomachine by means of at least one bearing and at least one of the two axial junctions which interacts with the element is mounted floating, that is to say that it is not carried directly by a bearing in the casing. It meshes on the one hand with splines of the monobloc element and on the other hand with splines or any other similar coupling of the turbine, compressor or blower, the latter being themselves supported by bearings in the casing.

According to an advantageous embodiment of the invention, the two axial junctions are fitted axially one inside the other.

According to an advantageous embodiment of the invention, one of the axial junctions overlaps the majority of the axial extent of the other junction.

According to an advantageous embodiment of the invention, the splines of the first set extend radially outwards, the turbomachine comprising a compressor coupled to the splines of the first set through the first axial junction.

According to an advantageous embodiment of the invention, the grooves of the second set extend radially inwards, the turbomachine comprising a fan coupled to the grooves of the second set by means of the second axial junction.

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According to an advantageous embodiment of the invention, a reduction gear is coupled to the grooves of the second set via the second axial junction, the blower being coupled to the splines of the second set via the reduction gear.

According to an advantageous embodiment of the invention, one of the first and second sets of grooves is provided to drive a first stage of blades of the fan and the other set of grooves causes a second stage of blades of the blower, possibly rotating in the opposite direction to the first stage by means of a reducer.

Brief description of the drawings

FIG. 1 illustrates an axial turbomachine in axial section

FIG. 2 illustrates a section of a part of the compressor with a drive shaft element according to the invention

Figure 3 shows a first embodiment of the drive shaft element according to the invention

FIG. 4 represents a second embodiment of the drive shaft element according to the invention

Figure 5 illustrates axially curved splines

Figure 6 illustrates radially and axially curved splines

Description of the embodiments

In the following description, the terms "internal" and "external" refer to a positioning relative to the axis of rotation of an axial turbomachine. The axial direction corresponds to the direction along the axis of rotation of the turbomachine. The radial direction is perpendicular to the axis of rotation. Upstream and downstream are in reference to the main flow direction of the flow in the turbomachine.

Figure 1 shows in a simplified manner an axial turbomachine. In this specific case, it is a double-flow turbojet engine. The turbojet engine 2 comprises a first level of compression, called a low-pressure compressor 4, a

2017/5255 g BE2017 / 5255 second compression level, called high-pressure compressor 6, a combustion chamber 8 and one or more turbine levels 10. In operation, the mechanical power of the turbine 10 transmitted via the central shaft 80 until the rotor 12 sets in motion the two compressors 4 and 6. The latter comprise several rows of rotor blades associated with rows of stator blades. The rotation of the rotor around its axis of rotation 14 thus makes it possible to generate an air flow and to compress it progressively until the inlet of the combustion chamber 8.

An inlet fan commonly designated as a fan, or blower, 16 is coupled to the rotor 12 and generates an air flow which is divided into a primary flow 18 passing through the various above-mentioned levels of the turbomachine, and a secondary flow 20 passing through a annular duct generating a thrust useful for propelling an aircraft.

The central drive shaft is made up of several elements including the one-piece element according to invention 30. This is located in the upstream part of the reactor.

FIG. 2 is a sectional view of a low pressure compressor of an axial turbomachine such as that of FIG. 1.

The rotor comprises several rows of rotor vanes 24. The low pressure compressor 4 comprises several rectifiers which each contain a row of stator vanes (26), in the sense that they are linked to the stator. The rectifiers are associated with fan 16 or a row of rotor blades to straighten their air flows, so as to convert the speed of the flow into static pressure. Each blade, rotor as stator, has a leading edge, a trailing edge, a lower surface and an upper surface; said surfaces connecting the leading edge to the trailing edge; just like the strings of dawn.

The transmission shaft which transmits the torque from the turbine 10 to the compressor 4 and the blower 16 is noted 80 in FIG. 1. In FIG. 2, only part of the shaft 80 is shown. A tube 74 which is connected to the

2017/5255 g BE2017 / 5255 turbine (connection not shown) transmits the torque upstream of the reactor. The tube 74 turns on itself around the axis 14.

A shaft element 30 according to the invention is fixed to the tube 74 so that the tube 74 drives the element 30 in rotation. This element drives the rotor vanes 24 of the low pressure compressor in rotation. The element 30 is mounted in the reactor casing by means of the bearings 84 and 86. An inner sleeve 72 is mounted in series to connect the element 30 to the blower, optionally by means of a reducer (not shown). An outer bell-shaped sleeve 70 is mounted in series on the element 30 to connect the element 30 to the rotor vanes 24 via the drum 25.

The couplings of parts 70, 72 and 74 to element 30 are made by sets of grooves 40, 50 and 60 respectively.

The general shape of the element 30 is axisymmetric. It comprises two cylindrical portions 32 and 36 connected by a conical portion 34. It has several sets of grooves 40, 50, 60 for coupling with neighboring parts.

The grooves of the first set of grooves are arranged on the cylinder 32. They engage in grooves of the bell 70, linked to the drum 25 which carries the rotor vanes 24. The second grooves 50 are also arranged on the cylinder 32. They engage in grooves of the sleeve 72. According to the invention, the first 40 and second 50 grooves overlap at least partially. In other words, there is at least one point on the axis 14 which "sees" radially the two sets of grooves 40 and 50.

In the example illustrated, the element 30 has a third set of grooves 60 for interacting with grooves in the tube 74 which is driven by the turbine.

In this example, the grooves 40 are external, in that they are located on the exterior surface of the element 30. The grooves 50 and 60 are internal in that they extend towards the interior of the element. 30. Other internal / external configurations are possible.

Thus, Figure 3 highlights the part 30 alone, with external grooves for engaging the tube (noted 74 in Figure 2). Other grooves

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BE2017 / 5255 additional may be provided. For example, a fourth set of splines can cause rotor blades downstream of those which are driven by the first set of splines. The third and fourth sets of grooves in Figure 3 are distant from the first and second sets. In particular, two sets are placed near one of the axial ends of the monobloc element while two others of the four sets are placed at the opposite axial end.

Figure 4 shows an alternative to the monobloc element described in Figure 3. Here, the grooves 40 which engage the rotor drum (25 in Figure 2) are internal and the grooves 50 which engage the sleeve driving the blower (72 on Figure 2) are external grooves. FIG. 4 also describes an example of two by two superposition of the first 40, second 50 and third 60 sets of splines.

Figures 5 and 6 show the male part of grooves 40 which are alternatives to straight grooves. In FIG. 5, the splines 40 are curved axially, that is to say that the interval between two successive splines or the thickness of the splines varies axially. In Figure 6 the grooves are both curved axially and radially.

The grooves of the female part remain straight.

These types of grooves are advantageous especially during assembly. They are also advantageous for giving the splines different properties when cold or hot, that is to say in transient state (on ignition) or in steady state (in operation) of the reactor. Also, the grooves stiffen each other. Indeed, the grooves of one set form radial ribs which increase the bending stiffness of the drive shaft where they axially overlap the ribs of the other set; and vice versa. In this way, the mass of the tree can be optimized.

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Claims (20)

Claims 1. One-piece element (30) of an axial turbomachine transmission shaft, of generally hollow axisymmetric shape and extending along its axis of symmetry (14) of a length greater than its average diameter comprising a first set of grooves (40 ) intended to cooperate with a first axial junction (70) and a second set of splines (50) intended to cooperate with a second axial junction (72) characterized in that the first and second sets of splines (40, 50) are overlap axially, at least partially. 2. One-piece element according to claim 1 comprising an annular partition (32) separating and / or radially connecting the first set of splines (40) of the second set of splines (50). 3. One-piece element according to one of claims 1 or 2, the splines of the first set (40) being external, and the splines of the second set (50) being internal. 4. One-piece element according to claim 3, the internal splines (40) being larger radially and / or axially than the external splines (50). 5. One-piece element according to one of claims 1 to 4, the grooves of the first set (40) extending axially over at least 10%, or over the majority of the length of the grooves (50) of the second set. 6. One-piece element according to one of claims 1 to 5, comprising a connection end, the first set of splines (40) and the second set of splines (50) being formed on or near said connection end. 7. One-piece element according to one of claims 1 to 6, characterized in that it comprises a central axial section with a first mean diameter, and a second mean diameter where the grooves of the first set and the second set overlap, the second mean diameter 2017/5255 12 BE2017 / 5255 being greater than the first average diameter, possibly at least 30%. 8. One-piece element according to one of claims 1 to 7, comprising a third set of grooves (60) overlapping at least partially axially the first and / or the second set of grooves (40, 50). 9. One-piece element according to one of the preceding claims, the grooves of at least one of the sets being curved so that the circumferential curvilinear thickness of the groove between two successive grooves varies along the axis of the element. . 10. One-piece element according to one of the preceding claims, at least one set of grooves has an annular envelope generally in the form of an ellipsoid or hyperboloid of revolution. 11. One-piece element according to one of the preceding claims, the element being made of maraging steel (martensitic aging steel). 12. One-piece element according to one of the preceding claims, the element being heat treated at least at its grooves. 13. Transmission shaft (80) of an axial turbomachine characterized in that it comprises at least one monobloc element (30) according to one of the preceding claims and two axial monobloc junctions (70, 72) each engaging respectively in a groove sets (40, 50). 14. Turbomachine (2), in particular an aircraft turbojet or turboprop comprising a blower (16), a low pressure turbine (10) and a low pressure compressor (4), the turbomachine being characterized in that it comprises a drive shaft (80) according to the preceding claim, wherein one of the two axial junctions (70) cooperates directly or indirectly with the low pressure turbine (10); and / or one of the two axial junctions (72) cooperates directly or indirectly with the blower (16); and / or one of the two axial junctions (74) cooperates directly or indirectly with the low pressure compressor (4). 2017/5255 13 BE2017 / 5255 15. A turbomachine according to the preceding claim, wherein the one-piece element (30) of the transmission shaft is mounted in the casing of the turbomachine by means of at least one bearing (84, 86) and at least one of the two axial junctions (70, 72, 74) which interact with the element are mounted floating. 16. Turbomachine according to one of claims 14 or 15, characterized in that the two axial junctions (70, 72) are fitted axially one inside the other. 17. Turbomachine according to the preceding claim, characterized in that one of the axial junctions (70) straddles the majority of the axial extent of the other junction (72). 18. Turbomachine according to one of claims 14 to 17, characterized in that the splines of the first set (40) extend radially outwards, the turbomachine comprising a compressor (4) coupled to the splines of the first set by the bias of the first axial junction (70). 19. Turbomachine according to one of claims 14 to 18, characterized in that the splines of the second set (50) extend radially inwards, the turbomachine comprising a fan (16) coupled to the splines of the second set (50 ) through the second axial junction (72). 20. Turbomachine according to the preceding claim, characterized in that it comprises a reduction gear coupled to the splines of the second set (50) by means of the second axial junction (72), the fan (16) being coupled to the splines of the second set (50) via the reducer. BE2017 / 5255