EP2042248B1 - Device for circular forming of a revolution piece, in particular a turbomachine exhaust case - Google Patents

Description

The invention relates to a device and a method for circular conformation of a part of revolution, in particular an exhaust casing of a turbomachine.

Turbomachine exhaust casings, particularly turbojet engines, are large-diameter parts made of nickel-based alloy by mechanical welding. The operations of welding the casing generate multiple deformations. This is why it is necessary to put the casing back to the round, that is to say, to restore a circular shape before continuing construction.

Currently, these rounding operations are performed in manual boiler making using a hammer. This tedious technique requires a skilled workforce, requires many hours of work, generates noise and causes musculoskeletal trauma that cause work stoppages.

We also know ( JP 07 178459 ) a method of circular conformation of a piece of revolution in which a rim is mounted on a numerically controlled lathe and the deflection of the surface of the rim is measured by a sensor provided on the lathe.

We also know ( US-A-5,634,361 ) a device for circular conformation of a piece of revolution comprising a unit provided with two conformation rollers movable along an axis and a shaping roll mounted movably along another axis. However, this device is not efficient and safe enough.

• une unité inférieure comportant deux galets de conformation montés mobiles suivant un axe X1 et un galet de conformation monté mobile suivant un axe Y1 ;
• une unité supérieure comportant deux galets de conformation montés mobiles suivant un axe X2 et un galet de conformation monté mobile suivant un axe Y2 ;
• un plateau tournant disposé entre l'unité inférieure et l'unité supérieure ;
• des moyens de blocage de la pièce de révolution sur le plateau tournant.

The subject of the invention is precisely a device and a method which remedy these drawbacks. These objects are achieved, according to the invention, by the fact that the shaping device comprises:

• a lower unit comprising two conformation rollers mounted movable along an axis X1 and a shaping roll mounted movably along an axis Y1;
• an upper unit comprising two conformation rollers movable along an axis X2 and a shaping roll mounted movably along an axis Y2;
• a turntable disposed between the lower unit and the upper unit;
• means for locking the piece of revolution on the turntable.

Advantageously, the axes X1 and Y1 on the one hand, X2 and Y2 on the other hand are coaxial.

The rollers are mounted on force actuators (or cylinder) and they exert a stress on the housing. Cylinders of the same unit exert efforts in opposite directions.

Thanks to these features the shaping device of a revolution piece of the invention makes it possible to put the piece to the round quickly avoiding the hours of work required according to the prior art.

Advantageously, the lower unit and the upper unit further comprise means for measuring the circularity and the diameter of the part of revolution.

These means consist, for example, of a probe and a resistive linear displacement sensor.

Preferably, the sensor is connected to an analog acquisition card of a digital control.

In a particular embodiment, the rollers of the upper unit are mounted on a beam pivotally mounted relative to a frame of the device between a first position in which the rollers are disengaged from the part of revolution and a second position in which the rollers are engaged on the piece of revolution.

Advantageously, the locking means of the part of revolution on the plate consist of three quarter-turn flanges and three locking jacks.

• un opérateur dispose la pièce à conformer sur un plateau tournant ;
• l'opérateur enclenche le cycle de travail
• une commande numérique bride la pièce sur le plateau tournant ;
• la commande numérique met la rotation le plateau tournant ;
• la commande numérique mesure le diamètre moyen de la pièce ainsi que les écarts de circularité maximum et minimum ;
• la commande numérique détermine la position des galets de conformation en fonction du diamètre moyen de la pièce ;
• la commande numérique place les galets à la position déterminée tout en poursuivant la rotation du plateau tournant.

The invention also relates to a method of circular conformation of a part of revolution, in particular of an exhaust fan of an airplane turbojet engine. According to this method:

• an operator arranges the part to be conformed on a turntable;
• the operator starts the work cycle
• a numerical control clamps the workpiece on the turntable;
• the numerical control turns the turntable;
• the numerical control measures the average diameter of the piece as well as the maximum and minimum circularity deviations;
• the numerical control determines the position of the conformation rollers as a function of the average diameter of the workpiece;
• the numerical control places the rollers at the determined position while continuing the rotation of the turntable.

A control cycle of the part is carried out after its rounding.

A touch-up cycle is performed if the inspection cycle revealed that the part was out of tolerance.

• la figure 1 est une vue d'ensemble en perspective d'un dispositif de conformation conforme à la présente invention ;
• la figure 2 est une vue en perspective du plateau tournant et des moyens de bridage ;
• la figure 3 est une vue en perspective de l'unité inférieure du dispositif de conformation représenté sur la figure 1 ;
• la figure 4 est une vue en perspective de l'unité supérieure du dispositif de conformation circulaire de l'invention représentée sur la figure 1 ;
• la figure 5 est une vue en perspective d'une unité de mesure faisant partie de l'unité inférieure ;
• la figure 6 est une vue en perspective d'une unité de mesure faisant partie de l'unité supérieure représentée sur la figure 7.
• la figure 7 est une vue schématique en coupe à travers un carter d'échappement d'une turbomachine ;
• la figure 8 est une vue schématique montrant la position des galets extérieurs et du galet intérieur.

Other features and advantages of the invention will become apparent upon reading the following description of an exemplary embodiment given by way of illustration with reference to the appended figures. In these figures:

• the figure 1 is an overall perspective view of a shaping device according to the present invention;
• the figure 2 is a perspective view of the turntable and clamping means;
• the figure 3 is a perspective view of the lower unit of the shaping device shown in FIG. figure 1 ;
• the figure 4 is a perspective view of the upper unit of the circular shaping device of the invention shown in FIG. figure 1 ;
• the figure 5 is a perspective view of a unit of measurement forming part of the lower unit;
• the figure 6 is a perspective view of a unit of measurement forming part of the upper unit shown on the figure 7 .
• the figure 7 is a schematic sectional view through an exhaust casing of a turbomachine;
• the figure 8 is a schematic view showing the position of the outer rollers and the inner roller.

On the figure 1 the general reference 2 designates a static frame and fixed to the ground. A lower unit, designated by the general reference 4, is mounted on a lower step 6 of the frame 2. An upper unit, designated by the general reference 8, is mounted on an upper step 10 of the frame 2. A turntable 12 is mounted on an intermediate step 14 of the frame 2. The turntable 12 supports a part of revolution, a turbojet exhaust casing in the example shown. The housing comprises a central hub 18 and arm portions 20 connected to the central hub 18. The central hub and the arms 20 are made in one piece by molding. A ferrule 22 connected to the arm 20 by arm members 24 constitutes a mechanically welded part of the exhaust casing. As a result of the welding operations, the ferrule 22 undergoes multiple deformations. This is why it is necessary to put it back in the round. A numerical control is provided near the frame 2. This numerical control is conventionally presented as a computer connected to the circular conformation device by a series of interfaces, for example by a PLC and power relays. Its function is the display of information and the control of the conformation device according to a program introduced in advance.

We have shown on the figure 2 the means for clamping the exhaust casing on the turntable 12. These means consist on the one hand by three quarter-turn flanges 26 and by three clamping jacks 28 arranged at 120 ° from each other. The quarter-turn flanges 26 are raised pneumatically and then pivoted by a quarter of a turn in order to clamp the exhaust casing 16 on the turntable 12. The quarter-turn flanges and the external clamping cylinders are controlled in position by sensors. mechanical limit switches. The clamping pressure is controlled by two pressure switches ensuring that the pressures are maintained. All position information is communicated to the numerical control.

The turntable is rotated by means of a motor 30 whose maximum speed is for example 600 revolutions / minute. The motor 30 is connected to a 1:10 reducer which is itself connected to a 1:12 reducer. In this way, the maximum speed of rotation of the plate is 5 revolutions per minute.

We have shown on the figure 3 a perspective view of the lower unit 4. Two rollers 32 are mounted on a support 34 which moves in translation along an axis X1. The displacement of the support 34 is controlled by a gear motor 36 which drives a ball screw. In the example, the diameter of the ball screw is 32 millimeters and its pitch is 5 millimeters. On the other hand, an inner roller 38 moves in translation along an axis Y1. The inner roller 38 is mounted on a support 40 whose displacement is controlled by a gear motor group 42. The gear motor 42 causes the carrier 40 to move by means of a ball screw. In the example, the diameter of the ball screw is 32 millimeters and its pitch is 5 millimeters. The assembly makes it possible to adjust the displacement of the rollers with an accuracy of 1 micrometer. Preferably, the axes X1 and Y1 are coaxial.

We have shown on the figure 4 a perspective view of the upper unit 8. It comprises a support 44 on which a beam 46 is pivotally mounted. A jack 47 acts on the beam 46 to rotate it. In the same way as the lower unit, the upper unit 8 has a first axis X2 and a second axis Y2. In the example, these two axes are coaxial. Two outer rollers 48 (partially visible on the figure 4 ) are movable in translation in the direction X2 under the action of a motor driving a ball screw (not visible in the figure). Similarly, an inner roller 50 (partially visible on the figure 4 ) is movable in translation along the axis Y2. It is driven by a gear motor 52 acting on a ball screw. The rollers 48 and 50 are moved via the tilt cylinder 48 between a first position in which they are disengaged from the part of revolution and a second position in which they are engaged on the part of revolution.

We have shown on the figure 5 a measurement unit 60 forming part of the lower unit 4. This measurement unit comprises a pneumatic cylinder of positioning 62. This jack ensures the support of a roller 64 integral with the rod of the cylinder 66 on the outer periphery of the piece of revolution. The measurement unit 60 measures the circularity and the diameter of the part. A measurement sensor is connected to the digital control. The sensor consists of a probe and a resistive linear displacement sensor. The latter is connected to an analog acquisition board of the numerical control. A comparator 68 allows manual control and adjustment of the unit.

We have shown on the figure 6 the unit of measurement 70 forming part of the upper unit 8. This unit is identical, in principle, to the measurement unit 60 described with reference to FIG. figure 5 . It comprises a pneumatic cylinder 72 whose rod 74 is secured to a support 76 on which is mounted the measurement sensor 78. The sensor 78 consists of a probe 80 and a resistive displacement sensor. The latter is connected to a digital control acquisition board.

Similarly, the way for the measurement unit 60, a comparator 82 allows manual control and adjustment of the unit.

We explained about Figures 7 and 8 , the way the ferrule 22 is returned to the round. This ferrule 22 has a lower portion 22a and an upper portion 22b that is to return to the round. For this purpose, it establishes in a first step (optional) a map of the deformation of the ends 22a and 22b of the shell 22. During this step, the average diameter of the piece is measured. as the maximum and minimum roundness deviations. The numerical control contains an algorithm that calculates, as a function of the deformation, how much it is necessary to deform the casing to put it in a circular shape, taking into account the elasticity of the metal. The numerical control places the rollers in the desired position thanks to the electric gear motor and the ball screws which allow to move them in translation along the axes X1, Y1, X2 and Y2, as explained above, the rotation of the turntable continuing. As can be seen more particularly on the figure 8 there are two outer rollers 32, respectively 48 between which is interposed an inner roller 38 respectively 50. Diagrammatically by the arrow 84 the direction of rotation of the part.

Before conformation of the part the deformation is 5 millimeters maximum. After conformation it is about five tenths of a millimeter.

Claims (12)

1. A circular-shaping device for a rotating part (16), especially an exhaust housing of a turbo engine, which comprises:

   - a unit (4) comprising two shaping rollers (32) mounted movably along an axis X1 and one shaping roller (38) mounted movably along an axis Y1; and a turntable, characterized in that it further comprises :

   - a second lower or upper unit (8) comprising two shaping rollers (48) mounted movably along an axis X2 and one shaping roller (50) mounted movably along an axis Y2;

   - the turntable being disposed between the lower unit (4) and the upper unit (8),

   - blocking means (26, 28) for the rotating part on the turntable (12).
2. The shaping device as claimed in claim 1, wherein the X1 and Y1 axes on the one hand, and X2 and Y2 axes on the other hand, are coaxial.
3. The shaping device as claimed in claim 2, wherein, since the rollers are mounted on cylinders (36, 42, 52) they exert a stress upon the exhaust housing (16).
4. The shaping device as claimed in claim 3, wherein in that the cylinders of a same unit (36, 42) exert oppositely directed forces.
5. The shaping device as claimed in one of claims 1 to 4, wherein the lower unit (4) and the upper unit (8) additionally comprise measuring means (60, 70) for the circularity of the rotating part.
6. The shaping device as claimed in claim 5, wherein the measuring means for the circularity of the rotating part are constituted by a sensor (64, 80) and by a resistive or other type of linear displacement transducer.
7. The shaping device as claimed in claim 6, wherein the transducer is linked to an analog data acquisition board of a numerical control.
8. The shaping device as claimed in one of claims 1 to 7, wherein the rollers of the upper unit (8) are mounted on a beam (46) mounted such that it can pivot relative to a stand (2) of the device between a first position, in which the rollers are disengaged from the rotating part, and a second position, in which the rollers are engaged on the rotating part.
9. The shaping device as claimed in one of claims 1 to 8, wherein the blocking means for the rotating part on the turntable (12) are constituted by three quarter-turn clamps (26) and by three blocking cylinders (28).
10. A circular-shaping process for a rotating part, especially an exhaust housing (16), for an aircraft turbojet engine, wherein

    - an operator arranges on a turntable the part (16) to be shaped;

    - the operator initiates the work cycle;

    - a numerical control clamps the part (16) to the turntable;

    - the numerical control sets the turntable (12) in rotation; characterized in that the numerical control measures the mean diameter of the part (16), as well as the maximum and minimum circularity variances;

    - the numerical control determines the position of the shaping rollers (32, 38, 48, 50) as a function of the mean diameter of the part; and

    - the numerical control places the rollers in the determined position, while continuing to rotate the turntable.
11. The process as claimed in claim 10, wherein a control cycle for the part is realized after this has been rounded.
12. The process as claimed in claim 11, wherein a retouching cycle is realized if the control cycle as claimed in claim 10 has revealed that the part (16) was out of tolerance.

Images