WO2008031974A1

WO2008031974A1 - Machine tool, in particular for drilling/riveting, and methods of operating it

Info

Publication number: WO2008031974A1
Application number: PCT/FR2007/051895
Authority: WO
Inventors: Michel Valiere; Didier Frangeard
Original assignee: Spie Sud-Ouest
Priority date: 2006-09-12
Filing date: 2007-09-10
Publication date: 2008-03-20
Also published as: FR2905620B1; FR2905620A1

Abstract

The invention relates to a machine tool (M) of the type combining a plurality of operational subassemblies required to perform operations such as drilling and/or riveting and assuming a plunging movement towards the workpiece (P) and being installed at the end of a movement-imparting station (R), the machine tool being noteworthy for the fact that it consists of an elongate support (100) which, on a first face, longitudinally accommodates at least one secondary linear motor unit (210) which cooperates with primary units (220) associated with at least one of the operational subassemblies (300, 400) equipping the machine tool (M). The invention also relates to methods of operating this machine tool. Applications: machining, drilling/riveting.

Description

MACHINE TOOL, IN PARTICULAR DRILLING-RIVETING AND ITS

WORKING METHODS

FIELD OF APPLICATION OF THE INVENTION

The present invention relates to the field of machine tools carrying out the conventional operations in aeronautical assembly such drilling operations, milling, riveting, etc .. and including adaptations to perform these operations in the best conditions. DESCRIPTION OF THE PRIOR ART

There exists in the prior art, the system described by the document EP 0 917 920 which proposes a platform moving on rails fixed to the workpiece and accommodating various functional subassemblies performing one or more of the operations herein. above recalled. These subassemblies are able to move transversely relative to the direction of the rails to allow a dive movement to the surface of the workpiece and to succeed on the same axis of work several functional subassemblies.

An almost equivalent device is described in document US Pat. No. 4,662,556, in which an aircraft cell is placed inside a logical structure substantially reshaping its shape and on which at least one platform accommodating a plurality of functional subassemblies capable of performing drilling, countersinking, riveting, etc. As for the device described above, the functional subassemblies are associated and arranged on a platform which is capable of moving in such a way as to allow the different functional subassemblies to work on the same axis with respect to the aircraft cell. This mobility is made possible thanks to the presence of the logical structure which consists in particular of a transverse pair of curved rails taking up the radius of the cell section and by a longitudinal pair rectilinear rail forming gantry moving on the curved rails and on which said platform moves.

The two outer modules described above can be associated with a subsequent interior module thanks to an internal logic structure, the movements of the outer module to participate in certain operations such as riveting.

This type of device has the advantage of grouping together on the same platform, the functional subsets necessary for a succession of repetitive operations. Nevertheless, the proposed implementation of such a platform requires an installation that can only rarely be implemented.

The alternative implementation of such operations by means of a robotic arm independent of the workpiece and offering expanded possibilities of movement, defines dimensions of space, stiffness and mass that do not meet the devices of the prior art. Indeed, the end of a robotic arm offers possibilities of movement and angular positioning that do not offer the devices of the prior art which allows in particular the use of such an arm on other parts than the only sections of aircraft cells. However, a robotic arm is limited as to the load that can move in its end. This load must not be cumbersome to avoid any limitation of setting in motion. In addition, this load must be rigid so that the operations performed by the functional sub-assemblies transported respect the required accuracy. However, if it includes several features such as drilling and riveting, the machine tool disposed at the end of a movement architecture must itself propose a frame to a plurality of tools and a plurality of means of Put into motion for these tools.

When the machine tool is disposed at the end of a setting station such as a robotic arm, this machine tool is conventionally referred to as effector. DESCRIPTION OF THE INVENTION

On the basis of this state of affairs, the applicant has carried out research aimed at proposing a machine tool or an effector capable of carrying out conventional aeronautical assembly operations such as drilling, countersinking, riveting, etc., by grouping the sub-assemblies together. functional assemblies making it possible to implement them while respecting the constraints of space, rigidity and mass necessary for setting in motion by a robotic arm.

Another criterion that has been endeavored to improve the applicant concerns the speeds and accelerations of realization of the various operations.

This research has led to the design of an effector or machine tool of the type that includes several functional subassemblies required for performing operations such as drilling and / or riveting and assuming a dive to the workpiece of manufacture and installing at the end of a setting station. According to the invention, this machine tool is remarkable in that it consists of an elongated support which accommodates longitudinally on a first face at least one linear motor secondary block cooperating with one or more primary blocks associated with at least one of functional subassemblies equipping the machine tool.

This feature is particularly advantageous in that it optimizes the speed of operations whose setting in motion is carried out by linear motor. In addition, the linear motor is a direct drive motor and does not require any means of motion transmission which makes the machine tool more compact and optimizes its rigidity.

Another advantage concerning the use of the linear motor is the perfect control of the movement in translation thanks to the control of the power and the position thanks to the measurement rules associated with it.

To optimize its rigidity, its bulk and its mass, the machine tool of the invention is furthermore remarkable in that the secondary block of the machine tool is shared by several functional subassemblies supported by the machine tool and associated or not to independent primary blocks.

According to the invention, the machine tool comprises a plurality of functional subassemblies which are not equipped with all the means of movement necessary for their function and which come for these movements to bind to a subset functional equipped with said moving means. In the context of the invention where several functional subassemblies carried by the support require a translational movement while diving towards the workpiece, only one subassembly equipped with a moving means is then necessary.

Thus, according to a particularly advantageous characteristic, the machine tool of the invention comprises a functional machining subassembly equipped with an electro-spindle associated with a linear motor primary block cooperating for the dive movement towards the workpiece, with the secondary block installed on said support, and

- At least one riveting functional subassembly equipped with a riveting nose and which binds punctually to the machining functional subassembly to be driven in translation by the latter.

Thus, thanks to the same secondary block several functional subassemblies are likely to be put moving. This characteristic defines not only the sharing of the secondary block but also that of the primary block. Indeed, by proposing the point association with the mobile subset constituted by the machining subassembly for its movements according to or parallel to the dive axis, the riveting module does not require means for independent movement. . Only the guide means are then necessary. The sharing of the means for setting in motion or part of the means of setting in motion makes it possible to reduce the volume and the cost of the machine tool, while optimizing the precision and the speed of the movements.

According to the invention, the point association between the subassemblies equipped with a moving means and those that are not equipped with it is implemented by actuator buffers which, together with non-equipped subassemblies, rely on the equipped subassembly (s) when moving is necessary. In addition, said riveting nose passes from a position where it is coaxial with the dive axis to a position where it is offset from the dive axis so as not to be an obstacle to the movement of the dive. dive of the machining subset.

According to another particularly advantageous characteristic, the machine tool comprises a press-plate module movably mounted relative to the support which is itself associated with a contact detection means made with the workpiece. In addition to the advantages of the simple presence of a sheet metal press for a drilling and / or riveting machine tool, this contact detection has the advantage of giving a basis for the calculation of the depth of the bores or milling made by the machine tool. According to a first implementation, the sheet metal press unit is associated with a linear motor primary block capable of moving on said secondary block - -

hosted by the support module. This possibility of displacement is exploited to detect the contact of the sheet metal press with the part, a contact which defines a constraint for the linear motor, a constraint translated into electrical current which can be detected by a digital control capable of triggering a measurement and therefore a reference coast for future rib chains of machining and / or assembly to be carried out. According to a second implementation, the sheet-metal press unit mounted movably relative to the support is associated with a means of detecting its movement that can trigger a measurement and therefore a reference coast for the future rib chains of the machining and / or assembly to be performed. According to another embodiment, the means for detecting the contact between the sheet metal press and the part also measure the force of said sheet metal press on the part, which effort in certain applications must be calibrated. This measurement of effort is ensured by strain gages.

In order to bring a plurality of additional functionalities to the machine tool, in particular in the display and marking of bores or other operations already performed on the surface of the workpiece, said support accommodates a means of shooting capable of ensuring probing or optical registration. This means of shooting managing the registration on two axes is advantageously associated with a laser managing a third axis.

In order to contribute to the rigidity without weighing down the machine tool, said support comprises on its face opposite to that accommodating said secondary block, a connecting structure with a fixing means on said setting station, said connecting structure being composed an assembly of perforated sections.

Still to offer more features, the machine tool is, according to another characteristic of the invention, associated with a tool change device cooperating with the electro-spindle. Thus, for example, the boring tool can be replaced by a milling tool and vice versa.

According to another particularly advantageous characteristic, the machine tool comprises a cowling protecting the subassemblies present on the support by being fixed to the latter.

According to a particularly advantageous characteristic, the setting station is constituted by a robotic arm which is able to make the best use of the optimized characteristics of mass, stiffness, bulk, precision and speed of execution offered by the machine tool described above.

The characteristics described above make it possible to envisage original work processes, other objects of the invention and to participate in a better realization of the operations conventionally performed on aeronautical parts.

A working method of such a machine tool is to define the exact position of the surface to be machined by detecting the contact of the sheet metal press with the workpiece.

Another working method based on a sheet metal press module associated with a linear motor primary block consists of defining the exact position of the surface to be machined by measuring the electric current passing through the motor during the contact.

Another method of work is to determine the volume in the space of the workpiece or the surface to be machined by the realization of a plurality of contacts between the workpiece and the sheet metal press. This method makes it possible to define a "normal" reference surface or surface that will serve as a reference for the following operations.

In addition, another working method for the - -

performing machining at predetermined intervals of a machine tool according to the invention equipped with a means of shooting is remarkable in that it consists in locating by video camera the first machining and to be added for the race of the machine tool from the raised position, the pre-established intervals for performing the following machining.

The basic concepts of the invention having been described above in their most elementary form, other details and characteristics will emerge more clearly on reading the description which follows and with reference to the appended drawings, giving non-limiting example, an embodiment of a machine tool or effector according to one invention. BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing of a workshop comprising a workpiece on which an embodiment of a machine tool according to the invention comes to work,

FIG. 2 is a schematic drawing of a perspective view of an embodiment of a machine tool according to the invention without its cowling,

FIG. 3 is a schematic drawing of another perspective view of the embodiment illustrated in FIG. 2 with its cowling,

FIG. 4 is a schematic drawing of a top view of the embodiment of FIG. 2,

Figure 5 is a schematic drawing of a detail view in perspective of a riveting subassembly. DESCRIPTION OF THE PREFERRED EMBODIMENTS

As illustrated in the drawing of Figure 1, the workshop hosts a manufacturing part P here constituted by an aircraft cell section positioned on a frame B provided for this purpose.

The machine tool referenced M represented schematically is the type of that grouping several functional subassemblies necessary for the realization of more or less conventional operations in aeronautical assembly such drilling operations, milling, riveting, etc .. and assuming a dive movement to the workpiece P.

As illustrated, the machine tool M is installed at the end of a setting station constituted here by a robotic arm R mounted on a longitudinal displacement carriage relative to the workpiece P. Thus, in accordance with the applications envisaged for the machine tool of the invention, the movement device is independent of the workpiece and its guide elements are not fixed to the piece P. A position that can take said machine tool M is illustrated in phantom interrupted short. The various possibilities of movement proposed by a robotic arm R such as that illustrated, define a progress in flexibility over the prior art which proposed a machine tool whose setting station was attached to the room or depended on a machine. logical structure taking the form of the piece. Nevertheless, such possibilities require a machine tool or an effector whose weight, rigidity and compactness have been optimized.

To meet these criteria, the applicant has devised a machine tool M such as that illustrated in more detail in Figures 2, 3, 4 and 5, constituted by a flat and elongate support 100 which accommodates longitudinally on a first face 110 at least a secondary block 210 of linear motor cooperating with primary blocks 220 associated with at least one of the functional subassemblies equipping the machine tool M.

According to the illustrated embodiment and according to the invention, several functional subassemblies are able to plunge towards the part P along the axis Z, ie the axis according to which said secondary block 210 is oriented to move in translation.

A first subassembly is the machining subassembly 300 consisting of an electro-pin 310 at the end of which can be rotated along the Z axis a tool 0 such as a drilling tool and / or milling, etc. This electro-pin 310 is integral with a carriage 320 associated with a primary block (not shown) cooperating with said secondary block 210 in order to set in translation movement the electro-pin 310 according to the double-arrow Fl along the axis Z. The setting station R sets the machine tool M in position and then it is the functional subassemblies that constitute it that ensure the work movements as the dive movement along the axis Z of the electro-spindle and the tool that it rotates to the piece P. Apart from the conventional operations of drilling and milling, this electro-spindle can set in motion clipping tools, shaving for sharpen the head of the rivet, surfacing to plan the piece and the rivet in position on the part, etc. Indeed, according to a particularly advantageous feature of the invention, the machine tool is associated with a non-illustrated tool change device cooperating with one electro-spindle .

A second subset movable in translation along the Z axis is a riveting subassembly 400 which, according to a non-limiting technological choice of the applicant, uses blind rivets. This riveting functional subassembly 400 is equipped with a delivery nose 410 providing rivet setting and rivet setting movements. To do this, the pose nose adopts two angular positions

••

a first angular position illustrated in FIG. 2 where it is coaxial with the rivet delivery pliers 500 (for the sake of clarity the rivets and the rivet feed means are not illustrated with the exception of their point of arrival on the machine tool namely said clamp 500),

- A second angular position illustrated in Figure 4 where the laying nose 410 is coaxial with the dive axis Z used by the electro-spindle 310.

The passage from one position to another is achieved by means of a pivot connection controlled by a rotary actuator. This passage from one position to another also makes it possible not to hinder the translational movement of the electrospindle 310 during the operations it carries out. As illustrated, the functional riveting sub-assembly 400 comprises a bracket 420 guided in translation along or parallel to the axis Z by means of a guide rule 120. The setting in motion is advantageously achieved by occasionally associating the subassembly rivet functional 400 to the machining functional subassembly 300. According to the proposed configuration, this translational movement corresponds to the rivet setting, rivet clearance, rivet setting and nose clearance phases. This stem 420 accommodates a means for guiding and moving in rotation consisting of a motor 430 driving in rotation along an axis A to an arm 440 connected to the nose 410. As explained above, this rotational movement allows to pass the axis of the laying nose from a coaxial position with the rivet delivery pliers 500 at a position coaxial with the axis of the electro-spindle 310.

In order to respect the objectives of the invention, the stem 420 of the riveting subassembly 400 adopts an inclined shape towards the inside of the machine tool M in order to arrange the kinematic elements and the pose nose that it supports as close to the axis of symmetry of the machine tool. Thus the mechanical assembly provides significant rigidity in the working axis of the machine tool.

According to the embodiment illustrated, the machine- M tool comprises another functional subset 600 having as for the riveting subassembly 400 a bracket supporting another nose 610 for another type of rivet or a module for providing a sealant. The possibility of integrating several riveters makes it possible to envisage several modes of operation.

For example, insofar as the two riveters pose the same rivet, the feeding operation of the rivet can be performed in masked time to reduce the cycle time. In addition, in a configuration where the rivets are of different types, such a machine tool will offer the possibility of installing several types of rivets without disassembling the effector or one of the functional subassemblies.

As illustrated in the drawing of FIGS. 2 and 5, the point association of machining subassembly 300 with those of riveting 400 and 600 for the purposes of moving in parallel with or parallel to the Z axis is achieved by means of at least one actuator pad Ta ensuring the securing and detaching of the mobile subassembly 400 or 600 not equipped with a moving means with the movable subassembly 300 equipped with a moving means. When the riveting subassembly 400 or 600 is disengaged from the machining subassembly, another actuator pad Tb ensures that it is held in position on the guide means 120 with which it is associated. Thus, the first actuator pad Ta moves from a disengaged position where the functional subset to which it is associated is independent, to an engaged position or the functional subset with which it is associated kinematically links along a motion axis to a other functional subset. The second buffer Tb has more a brake function which maintains in position the subset with which it is associated when it is independent. According to the invention, the machine tool M comprises a sheet-metal pressing module 700 which is itself associated with a linear motor primary block 220 able to move on said secondary block 210. The sharing of a same secondary block for several functional subassemblies contribute to the optimization of the space requirement and the gain in rigidity of the machine tool M.

The use of a sheet metal press stiffens and maintains the area of the part P subjected to machining or installation of the tool. The use of a sheet metal press 700 associated with a moving means makes it possible to very precisely adjust the force that can be transmitted to the surface of the part P. In addition, if this sheet metal press 700 is associated to contact sensing means and / or transmitted force as can be proposed a linear motor, the contact of the nose of the sheet metal press 700 can be detected and serve as basis for all machining operations likely to to be realized. This characteristic of real-time control of the position of the sheet metal press is particularly important for the milling operation, which must be able to propose milling at the right edge.

According to a particularly advantageous characteristic of the invention, the sheet metal press 700 is mounted on the machine tool M so as to allow rapid disassembly, especially in the event of a collision. Similarly, this sheet metal press retracts to allow automatic tool change.

To guide the movement of the functional subassemblies towards the part P, the flat support 100 accommodates on its sides at least one guide rule 120 of the movements in translation. Likewise, in order to propose the servocontrols of the positions of the different functional subassemblies, the flat support is also equipped with a measurement rule 130. The second face of the flat support serves as a connection with the setting station R. This second side has also been designed to meet the objectives of the invention. Thus, as illustrated in the drawing of FIG. 3, said flat support 100 comprises on its face opposite to that accommodating said secondary block 210 a connecting structure 800 with a fixing means 810 on said setting station R, said structure link 800 being composed of an assembly of flat profiles 820 openwork. The presence of openings inside the profiles contributes to the desired lightening.

According to the preferred embodiment illustrated, said connecting structure 800 adopts the flat support 100 on one side of which the upper ends of two connecting sections 820 are joined at the lower ends of which another flat profile 830 is fixed, said flat section accommodating the fastening means 810 embodied by a clamping flange.

According to another particularly advantageous feature of the invention, the machine tool M comprises a cowling 900 protecting the subassemblies present on the support 100 by fixing to the latter. According to a preferred embodiment, the cowling 900 is in two parts: a first portion 910 covering the greater part of the flat support from its end not equipped with the sheet metal press 700, a second part 920 covering a portion of lower volume located near the sheet metal press 700.

According to a feature not illustrated, said second portion 920 is perforated to allow the change of the tools of the electro-spindle 310.

It is understood that the machine tool and its work processes, which have just been described above and represented, have been for the purpose of disclosure rather than limitation. Of course, various arrangements, modifications and improvements may be made to the example above, without departing from the scope of the invention.

For example, this machine tool and its working method are applicable to all types of materials or assemblies of materials.

Claims

- -REVENDICATIONS

1. Machine tool (M) of the type of that comprising several functional subassemblies necessary for carrying out operations such as drilling and / or riveting and assuming a dive movement to the workpiece (P) and s installing at the end of a setting station (R), CHARACTERIZED BY THE FACT THAT it is constituted by an elongated support (100) which accommodates longitudinally on a first face at least one secondary block (210) of linear motor cooperating with primary blocks (220) associated with at least one of the functional subassemblies (300, 400) equipping the machine tool (M).

2. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT the secondary block (210) of the machine tool (M) is shared by several functional subassemblies (300, 400, 700) supported by the machine tool (M) and associated or not with independent primary blocks (220).

3. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it comprises a sheet-metal pressing module (700) which is itself associated with a primary block (220) of linear motor may move on said secondary block (210).

4. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it comprises a press-plate module (700) mounted movable relative to the support (100) and associated with a means for detecting its movement.

5. Machine tool (M) according to claim 1, CHARACTERIZED BY THE fact that said support (100) accommodates a means of shooting.

6. Machine tool (M) according to claim 1, CHARACTERIZED BY THE fact that the support (100) accommodates at least one of its sides a guide rule (120) translational movements.

Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it comprises a plurality of functional subassemblies, part of which (400, 600) is not equipped with all the means of movement necessary for their function and which comes for these movements to bind a functional subassembly (300) equipped with said moving means.

8. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it comprises a functional machining subset (300) equipped with an electro-spindle (310) associated with a primary block (220) linear motor cooperating for the dive movement to the workpiece (P) with the secondary block (210) installed on said support (100) and at least one riveting functional subassembly (400) equipped with a riveting nose ( 410) and which binds punctually to the machining functional subassembly (300) to be driven in translation by the latter.

9. Machine tool (M) according to claim 8, CHARACTERIZED BY THE FACT THAT said riveting nose (410) passes from a position where it is coaxial with the dive axis (Z) to a position where it is is offset from the dive axis (Z) so as not to be an obstacle to the dive movement of the machining subassembly (300).

10. Machine tool (M) according to claim 1, characterized by the fact that said support (100) comprises on its face opposite to that accommodating said secondary block (210) a connecting structure (800) with a fastening means ( 810) on said setting station (R), said connecting structure (800) being composed of an assembly of profiles (820) perforated.

11. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it is associated with a tool change device cooperating with the electrospindle.

12. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT it comprises a cowling (900) - -

protecting the subassemblies present on the support (100) by attaching to the latter.

13. Machine tool (M) according to claim 1, CHARACTERIZED BY THE FACT THAT the setting station (R) is constituted by a robotic arm.

14. A method of working a machine tool (M) according to claims 1, 3 and 4, CHARACTERIZED IN that it consists in defining the exact position of the surface to be machined by detecting the contact of the sheet metal press with the workpiece .

15. A method of working a machine tool (M) according to claim 14, CHARACTERIZED IN that it consists in defining the exact position of the surface to be machined by measuring the electric current flowing through the motor during the contact.

16. A method of working a machine tool (M) according to claims 1, 3 and 4, CHARACTERIZED BY THE FACT that it consists in determining the volume in the space of the workpiece or the surface to be machined by the performing a plurality of contacts between the workpiece (P) and the sheet metal press (700).

17. A method of working a machine tool (M) according to claims 1 and 5 for performing machining arranged at predetermined intervals, CHARACTERIZED BY THE FACT that it consists in identifying by video camera the first machining and to add for the stroke of the machine tool (M) from the raised position, the pre-established intervals for performing the following machining operations.