FR3092617A1 - SET INCLUDING AN ACCESSORY BOX FOR A TURBOMACHINE - Google Patents

Abstract

Assembly (1) for a turbomachine (2) comprising: - an accessory housing (3) comprising a first shaft (4) rotating about a first axis (A) and a second shaft (5) rotating about a second axis (B); - a first equipment (6) comprising a first rotor (7) rotating about said first axis (A) and coupled in rotation with said first shaft (4); - a second equipment (8) comprising a second rotor (9) coupled in rotation with said second shaft (5); characterized in that said first and second rotors (7, 9) are respectively rotatably coupled with said first and second shafts (4, 5) via a gearbox (10), said second rotor (9) is rotatable about a third axis (C) offset from said second axis (B), said second rotor (9) being rotatably coupled with said second shaft (5) via a gear train (11) of said gearbox (10) . Figure for the abstract: Figure 1

Description

SET COMPRISING AN ACCESSORY BOX FOR A TURBOMACHINE

Technical field of the invention

The present invention relates to an assembly comprising an accessory box for a turbomachine, this assembly further comprising equipment attached to the box.

Technical background

An accessory box for a turbomachine is known by the English acronym AGB for "Accessory GearBox".

An accessory box is intended to transmit mechanical power taken from the engine (or gas generator) of the turbomachine to equipment such as a pump, an alternator-starter, an air/oil separator, etc. Each piece of equipment is attached directly to an interface of the casing and comprises a rotor coupled in rotation with a drive shaft of the casing.

In order to limit the number of references, engine manufacturers try to standardize the different modules of a turbomachine, and in other words to use one and the same module for different turbomachines. An accessory box can be standardized, i.e. used for different turbomachines.

The equipment attached to an accessory box may vary from one turbomachine to another or have different dimensional or geometric characteristics.

Thus, on the basis of the same accessory box and for different turbomachines, engine manufacturers may be confronted either with mutual encroachment between two neighboring pieces of equipment, which prevents their assembly, or with non-optimal operation of one or more equipment due, for example, to an unsuitable rotation speed.

The objective of the present invention is thus to propose an assembly comprising an accessory box allowing, for different turbomachines, the assembly of all the equipment and optimal operation of the latter.

The invention proposes for this purpose an assembly for a turbomachine comprising:
- An accessory box comprising a first shaft rotating around a first axis A and a second shaft rotating around a second axis B parallel to said first axis A;
- A first piece of equipment attached to said housing, said first piece of equipment comprising a first rotor rotating around said first axis A and coupled in rotation with said first shaft;
- A second piece of equipment attached to said housing, said second piece of equipment comprising a second rotor coupled in rotation with said second shaft;
characterized in that said first and second rotors are respectively coupled in rotation with said first and second shafts via a gearbox, said second rotor is rotatable around a third axis C offset with respect to said second axis B and parallel to said first and second axes A, B, said second rotor being coupled in rotation with said second shaft via a gear train of said transmission box.

The transmission box, and more particularly the gear train, makes it possible to offset the axis of rotation C of the rotor of the second equipment with respect to the axis of rotation B of the second shaft, so as to avoid interference, it that is to say mutual encroachments between the first and second equipment, and/or to modify the operating parameters of the second equipment (rotation speed, torque, etc.), so that the second equipment operates on the range desired speed.

More generally, such a transmission box makes it possible to standardize the accessory box for different turbomachines which use different equipment. Indeed, the rotor of each piece of equipment can be coupled in rotation with the corresponding shaft of the housing either directly (without a gear train) or indirectly (with a gear train), depending on the space allocated and the the range of operating speeds desired for each piece of equipment.

The assembly according to the invention may comprise one or more of the following characteristics, taken separately from each other or in combination with each other:
- said second shaft is placed between said first and second rotors;
- said gear train comprises at least a first toothed wheel rotatable around said second axis B and a second toothed wheel rotatable around said third axis C;
- said gear train comprises a third toothed wheel meshed with said first and second toothed wheels;
- said gear train has a transmission ratio greater than 1;
- each of the equipment is attached to said transmission box, said first and second equipment being respectively mounted on first and second interfaces of said transmission box;
- Said transmission box comprises third and fourth interfaces respectively mounted on first and second interfaces of said accessory box;
- said first and second interfaces of said gearbox are respectively centered on said first and third axes A, C, said third and fourth interfaces of said gearbox being respectively centered on said first and second axes A, B, said first and second interfaces of said box being axially opposed to said third and fourth interfaces of said box;
- The first equipment is an alternator-starter and the second equipment is a hydraulic pump.

The present invention also relates to a turbine engine comprising an assembly as described previously.

Brief description of figures

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

FIG. 1 is a schematic front view of an assembly comprising in particular an accessory box and two pieces of equipment attached to the box;

Figure 2 is a schematic perspective view of the assembly shown in Figure 1;

Figure 3 is a schematic sectional view of the assembly along the plane P of Figure 2.

Detailed description of the invention

In Figures 1 to 3 is shown an assembly 1 for a turbomachine 2, such as a turbojet, a turboprop or an aircraft turbine engine.

The assembly 1 comprises on the one hand an accessory box 3 comprising a first shaft 4 rotatable around an axis A (first axis) and a second shaft 5 rotatable around an axis B (second axis) parallel to the axis A. The assembly 1 further comprises a first equipment 6 attached to the housing 3. The first equipment 6 comprises a first rotor 7 rotatable around the axis A and coupled in rotation with the first shaft 4. The assembly 1 also comprises a second equipment 8 attached to the housing 3. The second equipment 8 comprises a second rotor 9 coupled in rotation with the second shaft 5. The first and second rotors 7, 9 are respectively coupled in rotation with the first and second shafts 4, 5 via a transmission box 10. The second rotor 9 is rotatable around an axis C (third axis) offset with respect to the axis B and parallel to the axes A and B. The second rotor 9 is coupled in rotation with the second shaft 5 via a gear train 11 of the gearbox 10.

The accessory box 3 is intended to transmit mechanical power, taken from a motor (or gas generator) of the turbomachine 2, to the equipment 6, 8 via in particular the rotary shafts 4, 5.

The transmission box, and more particularly the gear train, makes it possible to shift the axis of rotation of the rotor of a piece of equipment relative to the axis of rotation of the corresponding drive shaft and/or to modify the equipment operating parameters (rotation speed, torque, etc.).

A gear train has a gear ratio set to operate the equipment within the desired operating range.

More precisely, with regard to the speed of rotation, in the case where it is desired to lower the speed of rotation of a shaft of the housing 3, the gear train 11 must be a reducer and thus have a transmission ratio of less than 1 On the contrary, in the case where it is desired to increase the speed of rotation of a shaft of the housing 3, the gear train 11 must be a multiplier and thus present a transmission ratio greater than 1. In the case where it is desired maintain the rotational speed of a shaft of the housing 3, the gear train 11 must have a transmission ratio equal to 1.

In the embodiment illustrated in the figures, the objective is not only to offset the second equipment 8 with respect to the first equipment 6, so as to position the first and second equipment 6, 8 one beside the other without interference, but also to modify the operating parameters of the second equipment 8.

According to the embodiment illustrated in the figures, the first equipment 6 is an alternator-starter and the second equipment 8 is a hydraulic pump.

The example illustrated in the figures is in no way limiting, the equipment could be different. Set 1 could further include more gear, with each gear paired with a rotating shaft of the accessory box. More precisely, the rotor of each piece of equipment is coupled in rotation with the corresponding drive shaft either directly (without a gear train, via for example an intermediate shaft) or indirectly (with a gear train) depending on the allocated footprint and the desired operating speed range for the equipment.

The gear train 11 comprises at least a first toothed wheel 12 rotatable around the axis B and a second toothed wheel 13 rotatable around the axis C.

According to the embodiment illustrated in the figures, the gear train 11 comprises a third toothed wheel 14 meshed with the first and second toothed wheels 12, 13. The third toothed wheel 12 is rotatable around an axis D (fourth axis ) parallel to the axes A, B and C. The axis D is located between the axis of rotation B of the first toothed wheel 12 and the axis of rotation C of the second toothed wheel 13. The toothed wheels 12-14 are with external contact and parallel axes. The gear train 11 is located in an interior enclosure 15 of the transmission box 10. The transmission box 10 is located axially between the equipment 6, 8 and the accessory box 3.

More precisely, as illustrated in particular in FIG. 3, the gear train 11 is here a multiplier and thus has a transmission ratio greater than 1. The second toothed wheel 13 and the third toothed wheel 14 have the same number of teeth. First gear 12 has more teeth than second and third gears 13, 14. First and third gears 12, 14 rotate clockwise and second gear 13 rotates counterclockwise. The second toothed wheel 13 is commonly called "an inverter" since it makes it possible to reverse the direction of rotation without however modifying the transmission ratio.

Each toothed wheel 12-14 is driven and guided in rotation via a shaft 16, the shaft 16 projecting from either side of the toothed wheel and centered on its axis of rotation. Each toothed wheel 12-14 is integral with the shaft 16. The toothed wheel 12-14 can be made in one piece with the shaft 16, so as to form an assembly more commonly called "a shaft pinion". The toothed wheel 12-14 can be attached to the shaft 16 and coupled in rotation with the shaft 16 via coupling means such as splines, a key, etc. The toothed wheel 12-14 can be attached to the shaft 16 and coupled in rotation with the shaft 16 via a shrink-fit assembly. The shaft 16 (and therefore the associated toothed wheel) is guided in rotation via for example two bearings arranged on either side of the toothed wheel. The gears 12-14 and the bearings are lubricated in the enclosure 15 using a liquid lubricant such as oil.

As a variant, the gear train could for example comprise one or more planetary gear trains.

According to the embodiment illustrated in the figures, the first rotor 7 and the first shaft 4 are coaxial and mobile in rotation around the axis A. The second rotor 9 is mobile in rotation around the axis C which is offset by relative to the axis of rotation B of the second shaft 5, so as to position here the first and second equipment 6, 8 one beside the other without interference. The second shaft 5 is placed between the first and second rotors 7, 9, and in other words the axis of rotation B of the second shaft 5 is placed between the axis of rotation A of the first rotor 7 and the axis of rotation C of the second rotor 9.

More precisely, the first shaft 4 is coupled in rotation with an intermediate shaft 27 via coupling means 17. In the same way, the first rotor 7 is coupled in rotation with the intermediate shaft 27 via coupling means 18 The intermediate shaft 27 is located inside the gearbox 10. The intermediate shaft 27 is centered on the axis A and guided in rotation via for example two bearings spaced apart from each other. The bearings are lubricated in enclosure 15. Intermediate shaft 27 rotates clockwise here (Figure 3). The coupling means 17, 18 can be splines formed in the first shaft 4 and the intermediate shaft 27 (respectively in the first rotor 7 and the intermediate shaft 27), or even a key housed partly in a groove of the first shaft 4 and partly in a groove of the intermediate shaft 27 (respectively in the first rotor 7 and the intermediate shaft 27).

The second shaft 5 is coupled in rotation with the first toothed wheel 12 via coupling means 19. In the same way, the second rotor 9 is coupled in rotation with the second toothed wheel 13 via coupling means 20. The coupling means 19, 20 can be splines made in the second shaft 5 and the first toothed wheel 12 (respectively in the second rotor 9 and the second toothed wheel 13), or even a key housed partly in a groove of the second shaft 5 and partly in a groove of the first toothed wheel 12 (respectively in the second rotor 9 and the second toothed wheel 13).

As illustrated in the figures, each of the items of equipment 6, 8 is attached to the transmission box 10. The first and second items of equipment 6, 8 are respectively placed and held in position on first and second interfaces 21, 22 of the box transmission 10. The first and second interfaces 21, 22 of the gearbox 10 are respectively centered on the axes A and C. The first and second interfaces 21, 22 are for example each in the form of a boss.

The positioning of equipment 6, 8 vis-à-vis the corresponding interface 21, 22 is for example carried out via a support-plan connection and short centering. The equipment 6, 8 is for example held in position via a plurality of screws, each screw simultaneously passing through a through hole made in the stator of the equipment and a tapped hole made in the interface.

Sealing means can be arranged between the equipment and the corresponding interface.

As illustrated in the figures, the transmission box 10 comprises third and fourth interfaces 23, 24 respectively placed and held in position on the first and second interfaces 25, 26 of the accessory box 3. The third and fourth interfaces 23 , 24 of the transmission box 10 are respectively centered on the axes A and B. The third and fourth interfaces 23, 24 are axially opposite the first and second interfaces 21, 22 of the box 10. The third and fourth interfaces 23, 24 of the box 10 as well as the first and second interfaces 25, 26 of the box 3 are each, for example, in the form of a boss comprising a peripheral collar at its free end.

The positioning of an interface 23, 24 of the box 10 vis-à-vis a corresponding interface 25, 26 of the box 3 is for example carried out via a support-plan connection and a short centering. The interfaces 23-26 of the box 10 and of the box 3 are for example held in position via a clamping collar enclosing two contiguous collars, namely a collar of an interface 23, 24 of the box 10 and a collar of a interface 25, 26 of box 3.

Sealing means can be arranged between an interface of the box and a corresponding interface of the housing.

Such an assembly of the transmission box 10 makes it possible to evenly distribute the mass of the equipment 6, 8 and of the box 10 on the interfaces 25, 26 of the box 3.

Claims (10)

Assembly (1) for a turbomachine (2) comprising:
- an accessory box (3) comprising a first shaft (4) rotatable around a first axis (A) and a second shaft (5) rotatable around a second axis (B) parallel to said first axis (A) ;
- a first piece of equipment (6) attached to said housing (3), said first piece of equipment (6) comprising a first rotor (7) rotatable around said first axis (A) and coupled in rotation with said first shaft (4);
- a second equipment (8) attached to said housing (3), said second equipment (8) comprising a second rotor (9) coupled in rotation with said second shaft (5);
characterized in that said first and second rotors (7, 9) are respectively rotationally coupled with said first and second shafts (4, 5) via a gearbox (10), said second rotor (9) is rotatable around a third axis (C) offset with respect to said second axis (B) and parallel to said first and second axes (A, B), said second rotor (9) being coupled in rotation with said second shaft (5) via a gears (11) of said gearbox (10). Assembly (1) according to claim 1, characterized in that said second shaft (5) is placed between said first and second rotors (7, 9). Assembly (1) according to one of the preceding claims, characterized in that said gear train (11) comprises at least a first toothed wheel (12) rotatable around said second axis (B) and a second toothed wheel (13) rotatable about said third axis (C). Assembly (1) according to claim 3, characterized in that said gear train (11) comprises a third toothed wheel (14) meshed with said first and second toothed wheels (12, 13). Assembly (1) according to one of the preceding claims, characterized in that the said gear train (11) has a transmission ratio greater than 1. Assembly (1) according to one of the preceding claims, characterized in that each of the equipment items (6, 8) is attached to the said transmission box (10), the said first and second equipment items (6, 8) being respectively mounted on first and second interfaces (21, 22) of said transmission box (10). Assembly (1) according to one of the preceding claims, characterized in that said transmission box (10) comprises third and fourth interfaces (23, 24) respectively mounted on first and second interfaces (25, 26) of said transmission box. accessories (3). Assembly (1) according to Claim 7 dependent on Claim 6, characterized in that the said first and second interfaces (21, 22) of the said transmission box (10) are respectively centered on the said first and third axes (A, C ), said third and fourth interfaces (23, 24) of said gearbox (10) being respectively centered on said first and second axes (A, B), said first and second interfaces (21, 22) of said gearbox (10 ) being axially opposite said third and fourth interfaces (23, 24) of said box (10). Assembly (1) according to one of the preceding claims, characterized in that the first equipment (6) is an alternator-starter and the second equipment (8) is a hydraulic pump. Turbomachine (2) comprising an assembly (1) according to one of the preceding claims.