Adaptive rotary or linear friction welding system

Abstract

One aspect of the invention relates to an adaptive rotary or linear friction welding system, comprising: a rotary friction welding device comprising a rotating member; and a removable adaptive module comprising a motion transformation mechanism for transforming a rotary motion into an alternating translational motion, the motion transformation mechanism comprising a fixing mechanism for being connected to the rotating member of the rotary friction welding device, the adaptive module further comprising a translationally movable head fixed at the output of the motion transformation mechanism, so as to perform an alternating translational motion when the rotating member of the rotary friction welding device is rotated. Figure to be published with the abstract: Figure 2b.

Description

Title of the invention: Adaptive rotary or linear friction welding system TECHNICAL FIELD OF THE INVENTION

[0001] The technical field of the invention is that of friction welding, in particular linear or rotary friction welding. TECHNOLOGICAL BACKGROUND OF THE INVENTION

[0002] To assemble metallurgical parts, it is known to use friction welding processes. In a friction welding process, the mechanical parts to be assembled are rubbed and pressed against each other. The friction between the parts to be assembled creates heat at the friction interface and the two mechanical parts become plastic at the interface. The movement is then stopped, the mechanical parts are pressed against each other and weld together by atomic diffusion.

[0003] We classically distinguish three modes of friction: rotary friction, linear friction and orbital friction.

[0004] In rotary friction welding (also called rotational friction welding), one of the parts is rotated and the other part (which is not rotated) is brought closer to the first part (docking phase). The two parts are thus brought into contact with each other, which generates heat at the contact interface. This phase is called the heating phase. The generated heat increases the temperature at the contact interface and the parts plasticize locally. The rotation is stopped, the parts are pressed against each other. The two parts are kept under pressure while they cool.

[0005] The docking phase and the heating phase constitute a phase called the “friction phase”, which is followed by the forging phase.

[0006] There are two types of rotary friction welding: controlled friction welding and inertial friction welding (or free friction welding). In controlled friction welding, the machine is directly driven, meaning that the motor directly provides the friction torque during the warm-up phase. In inertial friction welding, the part is rotated using a flywheel that rotates at high speed, is allowed to rotate freely, and will stop naturally due to the friction between the two mechanical parts. In other words, during the warm-up phase, the motor no longer drives the flywheel (and therefore the rotating mechanical part).

[0007] Rotary friction welding parameters are fixed and may depend on the type of friction among piloted friction (PF) and inertial friction (FI). These parameters are classically one or more parameters among: • the mass and / or a dimension (for example the radius) of the flywheel: FI; • friction speed: FP and FI; • the friction duration: FP; • the friction force: FP and FI; • the forging duration: FP; • the forging effort: FP and FI.

[0008] The first four parameters relate to the friction phase and the last two relate to the forging phase. The friction speed corresponds to the rotation speed of the motor in the case of controlled friction, and to the initial rotation speed of the flywheel in the case of inertial friction. The friction duration is defined for controlled friction as the duration during which the two parts are in contact while the first part is rotating (it therefore corresponds to the duration of the heating phase). The friction force corresponds to the pressure exerted by the two mechanical parts on each other during the heating phase. The forging time corresponds to the duration during which the parts are pressed against each other during the forging phase. The forging force corresponds to the pressure exerted by the two mechanical parts on each other during the forging phase.

[0009] These parameters are typically determined upstream of the welding process according to the dimensions of the parts to be welded (for example their diameters) and the material(s) which compose them.

[0010] A rotary friction welding process is illustrated in [Fig.1a]. The first mechanical part 1 is rotated and the second mechanical part 2 is brought into contact with the first mechanical part 1. In this example, the first mechanical part 1 performs a rotational movement around the x axis, and the second mechanical part 2 is approached to the first mechanical part 1 in the x direction. At the end of the process, an assembly 3 is obtained which comprises a welding bead 4 (which can then be removed by machining).

[0011] The rotary friction welding process is conventionally used to join parts having rotational symmetry, for example pipes and bars with a cylindrical or polygonal (for example hexagonal or octagonal) section.

[0012] In linear friction welding, one of the parts is driven in translation to perform a reciprocating motion (also called "reciprocating rectilinear translational motion" or "reciprocating motion" or "reciprocating linear motion" or "reciprocating translational motion"), and the other mechanical part (which does not perform a translational motion) is brought closer to the first part. The two mechanical parts are thus brought into contact with each other, in a manner similar to rotary friction welding. The translational motion of the first part is then stopped, and the two parts are pressed together while they cool.

[0013] The linear friction welding process can be conventionally used to assemble parts having rectangular or generally rectangular sections. Such a process is for example used in the manufacture of turbine blades, in particular aircraft engine turbines.

[0014] The parameters of a linear friction welding process are conventionally one or more parameters among: • the friction amplitude; • the friction frequency; • the duration of friction; • the friction force; • the forging time; and • the forging effort.

[0015] The first four parameters relate to the friction phase and the last two relate to the forging phase. The friction amplitude corresponds to the amplitude of the alternating translational movement (for example the amplitude of the movement of the head of a linear friction welding machine to which one of the mechanical parts to be welded is fixed). The friction frequency corresponds to the frequency of the alternating translational movement (for example the number of back-and-forth movements of the head of the welding machine per second). The friction duration corresponds to the duration during which the two parts are in contact while the first part is in alternating translational movement (it therefore corresponds to the duration of the heating phase). The friction force corresponds to the pressure exerted by the two mechanical parts on each other during the heating phase.The forging time corresponds to the duration during which the parts are pressed against each other during the forging phase. The forging force corresponds to the pressure exerted by the two mechanical parts on each other during the forging phase.

[0016] These parameters are typically determined upstream of the welding process according to the dimensions of the parts to be welded (for example their diameters) and the material(s) which compose them.

[0017] A linear friction welding process is illustrated in [Fig.lb]. In this example, the first mechanical part 1 performs a reciprocating movement in a direction y, and the second mechanical part 2 is approached to the first mechanical part 1 in the direction x, the axes x and y being orthogonal. As for rotary friction welding, the assembly 3 obtained comprises a welding bead 4.

[0018] Finally, in orbital friction welding, one of the parts performs a movement that combines rotation and translation (orbital motion), and the other part is brought closer to the first part. When the movement stops, the two parts are pressed together to form the weld.

[0019] The choice of friction mode typically depends on the geometry of the mechanical parts to be assembled and / or the functional requirements at the welds.

[0020] There are specialized machines that are very efficient and very expensive for making friction welding assemblies, each machine being dedicated to a single friction mode among rotary friction, linear friction and orbital friction. Each machine therefore has its own capabilities exclusive to a friction mode as well as its own calibration. Consequently, depending on the type of parts to be assembled, it is advisable to choose the appropriate friction mode and average machine and to begin a machine calibration phase through a test plan, in order to be able to make welds that comply with norms and standards.

[0021] A manufacturer using or offering mechanical parts assembled by rotary friction and mechanical parts assembled by linear friction must therefore have machines dedicated to each of these categories of friction, which represents a considerable investment in terms of cost and calibration of the machines.

[0022] The invention improves the situation. Summary of the invention

[0023] The invention provides a solution to the problems mentioned above, by making it possible to adapt a rotary (resp. linear) friction welding machine to linear (resp. rotary) friction welding. A module is thus proposed that can be adapted to conventional rotary (resp. linear) friction welding machines to perform linear (resp. rotary) friction. The module makes it possible to transform the rotary (resp. alternating translational) movement of the rotary (resp. linear) friction welding machine into an alternating translational (resp. rotational) movement to perform linear (resp. rotary) friction. The invention thus makes it possible to use machines dedicated to one friction mode to perform another friction mode. It is thus no longer necessary to have two types of machines, which represents a considerable saving in terms of cost and human investment (to learn how to use the machines and perform calibrations).

[0024] One aspect of the invention thus relates to an adaptive rotary or linear friction welding system, comprising: • a rotary friction welding device comprising a rotary member for rotating a mechanical part to be welded fixed to said rotary member when the device is used for friction welding rotary; and a removable adaptive module comprising a motion transformation mechanism for transforming a rotary motion into an alternating translational motion, the motion transformation mechanism comprising a fixing mechanism for being connected to the rotary member of the rotary friction welding device, the adaptive module further comprising a translationally movable head fixed at the output of the motion transformation mechanism, so as to perform an alternating translational motion when the rotary member of the rotary friction welding device is rotated.

[0025] By "adaptive rotary or linear friction welding system" is meant a system allowing either rotary friction or linear friction to be carried out. The adaptive system of the invention in fact comprises a rotary friction welding device, as well as an adaptive module which can be removably mounted on the rotary friction welding device, and which allows the rotary friction welding device to be adapted into a linear friction welding device.

[0026] By rotary (resp. linear) friction device or system is meant a device or system comprising means for rotating (resp. alternating translational movement) a part to be welded in order to weld this part by rotary (resp. linear) friction to another part.

[0027] By "adaptive module" is meant a device capable of being mounted on the rotating member of the rotary friction welding device. This adaptive module is removable, and can be mounted and dismounted depending on whether rotary or linear friction is desired.

[0028] The rotary member of the rotary friction welding device is a rotary member intended to be connected (directly or indirectly) to a mechanical part to be welded when the welding device is used in a conventional manner, to perform rotary friction. When the system is used to perform linear friction, the adaptive module is connected to the rotary member. When the rotary member is in rotational movement, the movable head is driven in reciprocating translational movement.

[0029] For example, the rotating member of the rotary friction welding device may include a fastening system for fastening a mechanical part to be welded to the rotating member when the welding device is used to perform rotary friction. When the system is used to perform linear friction, the fastening mechanism of the motion transformation mechanism cooperates with the fastening system of the rotating member.

[0030] In one embodiment, the translationally movable head is provided with an element for fixing a first mechanical part to be welded to drive said first mechanical part to be welded in an alternating translational movement when the rotating member of the rotary friction welding device is rotated.

[0031] Another aspect of the invention relates to an adaptive linear or rotary friction welding system, comprising: • a linear friction welding device comprising a translationally movable head for setting into reciprocating translational movement a mechanical part to be welded fixed to said translationally movable head when the welding device is used to carry out linear friction welding; and • a removable adaptive module comprising a movement transformation mechanism for transforming an alternating translational movement into a rotary movement, the movement transformation mechanism comprising a fixing mechanism for being connected to the translationally movable head of the linear friction welding device, the adaptive module further comprising a rotary member fixed at the output of the movement transformation mechanism so as to be rotated when the translationally movable head of the linear friction welding device is put into alternating translational movement.

[0032] Such a system comprises a linear friction welding device, as well as an adaptive module which can be removably mounted on the linear friction welding device, and which allows the linear friction welding device to be adapted into a rotary friction welding device.

[0033] In one embodiment, the rotary member is provided with an element for fixing a first mechanical part to be welded to drive said first mechanical part to be welded in a rotational movement when the translationally movable head of the linear friction welding device is put into reciprocating translational movement.

[0034] In one embodiment of either of the above systems, the system further comprises a translationally movable member, the translationally movable member being provided with means for fixing a second mechanical part to bring said second mechanical part closer to the first mechanical part in order to weld them together.

[0035] In one embodiment of either of the above systems, the rotary member is configured to rotate about a first predetermined axis, and wherein the translationally movable head is configured to perform an alternating translational movement along a second predetermined axis, the first axis and the second axis being orthogonal.

[0036] For the purposes of the present invention, “orthogonal” means that the two axes form an angle between 80° and 100°.

[0037] Of course, other embodiments are conceivable. For example, the first axis and the second axis may be parallel (or form an angle between 0 and 10°).

[0038] The motion transformation mechanism may be a connecting rod-crank mechanism, i.e. a mechanical assembly comprising a connecting rod and a crank, in which a rotational movement of the crank drives one end of the connecting rod in an alternating linear translational movement, and vice versa.

[0039] The adaptive module can thus comprise a rotating part on which a pin is fixed, the pin being eccentric relative to a surface of the rotating part, in which the pin is connected by at least one mechanical connection to the translationally movable head so as to drive the translationally movable head in an alternating translation movement when the rotating part is rotated.

[0040] The rotating part can be for example a cylindrical part, but other geometries are possible.

[0041] By "off-center with respect to a surface of the rotating part", it is understood that the pin is connected by a mechanical connection to a point on the surface of the rotating part, said point being a non-zero distance from the center of the surface. For example, the pin may be fixed on a surface of the rotating part, at a non-zero predetermined distance from the center of said surface. The predetermined distance is advantageously variable. This makes it possible to vary and adapt the vibration or rotation frequency at the output of the mechanism.

[0042] For example, the rotating part may include a fastening element cooperating with the fastening system of the rotating member of the rotary friction welding device, such that the rotating part is rotated when the rotating member is rotated.

[0043] In embodiments, the system further comprises a computing module configured to: • receive a target material consumption value; • determine a set of welding device input parameters from the target material consumption value.

[0044] Material consumption is a parameter commonly used in the field of welding to characterize the quality of the welding. It represents the quantity of material “consumed” during welding, i.e. the quantity of material from the part to be welded which goes into the welding bead. The computer module thus makes it possible to determine, from a desired material consumption value, the input parameters of the welding device (by rotary friction according to the first aspect of the invention, by linear friction according to the second aspect of the invention).

[0045] For example, determining the set of input parameters of the device welding can be performed via a function translating a link between rotary friction welding parameters and linear friction welding parameters.

[0046] The function translates in particular the link between the parameters of the rotary (resp. linear) friction welding device and the parameters of the linear (resp. rotary) friction welding system.

[0047] When the system includes a rotary friction welding device adapted to perform linear friction, the set of input parameters of the welding device may include at least one of: a mass of the rotary member, a dimension of the rotary member, and a rotational speed of the rotary member.

[0048] When the system comprises a linear friction welding device adapted to perform rotary friction, the set of input parameters of the welding device may comprise at least one of: an amplitude of reciprocating translational movement of the translationally movable head and a frequency of reciprocating translational movement of the translationally movable head.

[0049] In embodiments where the motion transformation mechanism comprises a pin attached to a rotating part, the set of input parameters of the welding device may further comprise an eccentricity value of the pin relative to the surface of the rotating part.

[0050] The eccentricity value is for example the distance of the pin from the surface of the rotating part.

[0051] In embodiments, the computer module is further configured to receive a value of a geometric parameter and / or a value of a mechanical parameter of a mechanical part to be welded, wherein the set of input parameters of the welding device is further determined from the value of the geometric parameter and / or the value of the mechanical parameter of the mechanical part to be welded.

[0052] The geometric parameter is for example a dimension of the mechanical part to be welded and the mechanical parameter is for example at least one material constituting the mechanical part to be welded.

[0053] The invention and its various applications will be better understood upon reading the following description and examining the accompanying figures. BRIEF DESCRIPTION OF THE FIGURES

[0054] Other characteristics and advantages of the invention will appear on reading the description, which can be read in conjunction with the figures. These figures are presented for information purposes only and in no way limit the invention.

[0055] [Fig. la] [Fig. la] represents a rotary friction welding method according to the prior art.

[0056] [Fig.lb] [Fig.lb] represents a linear friction welding process according to the prior art.

[0057] [Fig.2a] [Fig.2a] represents a rotary friction welding machine according to the prior art.

[0058] [Fig.2b] [Fig.2b] represents a linear friction welding system according to one embodiment of the invention.

[0059] [Fig.3] [Fig.3] represents a kinematic diagram of an adaptive module according to an embodiment of the invention.

[0060] [Fig.4] [Fig.4] shows an example of a motion transformation mechanism configured to be connected to a rotary friction welding machine according to one embodiment of the invention.

[0061] [Fig.5a] [Fig.5a] represents a linear friction welding machine according to the prior art.

[0062] [Fig.5b] [Fig.5b] represents a rotary friction welding system according to one embodiment of the invention. DETAILED DESCRIPTION

[0063] [Fig.2a] represents a rotary friction welding machine according to the art prior.

[0064] The rotary friction welding machine 100 shown in [Fig.2a] comprises a rotary member 6 configured to be rotated about an axis 11 (called the welding axis) parallel to an axis x. The rotary member 6 is connected (for example via a rotation shaft) to a rotation element 5 comprising means (such as a motor) for rotating the rotary member 6. The rotation element 5 may for example comprise a body fixed to a base 10, the body and the base 10 being fixed elements of the frame of the machine 100. Alternatively, the rotation element 5 may be configured to move in translation parallel to the axis x (thus allowing the first mechanical part 1 to be brought closer to the second mechanical part 2). In this alternative, the rotating element 5 can for example be placed on a rail arranged on at least part of the surface of the base 10, parallel to the x axis.

[0065] The rotating member 6 comprises or is connected to a fixing means 7, for example a clamp or a pliers, for temporarily fixing a first mechanical part 1 to the rotating member 6. When the rotating member 6 is rotated, the first mechanical part 1 is thus also rotated about the axis 11.

[0066] By “includes or is connected to”, it is understood that the fixing means 7 may be a part of the rotating member 6 (in which case the rotating member 6 and the fixing means 7 form a single mechanical part), or may be mounted on the rotating member 6, e.g. example in a removable manner. Thus, it is possible to change the fixing means 7 depending on the first mechanical part 1 to be assembled, or when the fixing means becomes too worn. In the case where the fixing means 7 is not a part of the rotating member 6 but is connected to the rotating member 6, it is always considered, within the meaning of the present invention, that the machine 100 without the fixing means 7 is a rotary friction welding machine.

[0067] The machine 100 also comprises a guide member 8 capable of being moved in translation parallel to the x axis, so as to bring the second part 2 closer to the first mechanical part 1 to assemble the two mechanical parts 1, 2 by rotary friction. The guide member 8 may for example be placed on a rail arranged on at least part of the surface of the base 10, parallel to the x axis.

[0068] The guide member 8 comprises or is connected to a fixing means 9, for example a clamp or a pliers, for temporarily fixing a second mechanical part 2 to the guide member 8. When the guide member 8 is set in translational movement along the x axis, the second mechanical part 2 is thus also set in translational movement along the x axis and can be brought closer to the first mechanical part 1.

[0069] It is noted that in certain embodiments, the guide member 8 can be provided with a rotation shaft and be connected to an intermediate rotating part on which the fixing means 9 is mounted. In these embodiments, the second mechanical part 2 can therefore also be rotated for welding.

[0070] To determine the input parameters of the rotary friction welding machine 100, it is known to use a function, here called a pass function or pass matrix, which associates with a set of welding parameters a value of the material consumption by the welding process according to said set of parameters.

[0071] It is recalled that the material consumption represents the loss of material (or equivalently the loss of length) during the friction welding process. This material consumption thus corresponds to the material which constitutes the welding bead. It conventionally includes the material consumption in the friction phase (i.e. the loss of material during the friction phase) and the material consumption in the forging phase (i.e. the loss of material during the forging phase). It can be defined for both assembled parts or for one of these parts only.

[0072] As mentioned previously, the welding parameters for rotary friction include one or more of: mass and / or a dimension of the flywheel, friction speed, friction time, friction force, forging time and forging force.

[0073] The passage function is therefore a function f such that f ( er j, er2, ..., er / i ) — CM, °where fl is a non-zero natural integer, erj, ? = L • • •, n is a welding parameter and CM is the material consumption during the welding process. The transition function f is typically defined for a set of parameters characteristic of the parts to be joined, for example their materials, shapes and dimensions. The subscript} here indicates that the transition function corresponds to a rotary friction welding process.

[0074] Conversely, the pass function can be used to determine, from a target material consumption (and the parameters of the parts to be assembled), a set of welding parameters: ( (JM ) = { er b , er^} ■

[0075] The passage function (and its inverse) are generally determined from experiments on real parts (descriptive part) and from simulations (predictive part). Its determination generally requires a large number of experiments, and therefore significant time, financial and computational investments. As the welding parameters are different depending on the friction mode used (rotary or linear), the passage function is also different depending on the friction mode. Thus, if a manufacturer used to performing rotary friction welding wishes to perform linear friction welding using a machine dedicated to linear friction welding, he must determine a new passage function about which he has no a priori knowledge and must therefore again implement a large number of experiments with the linear friction welding machine.

[0076] This switching function is typically implemented on a processor connected to the welding machine 100 or separate from the welding machine 100.

[0077] [Fig.2b] represents a linear friction welding system according to one embodiment of the invention.

[0078] In Figures 2a and 2b, the common elements have the same reference numerals. The system 100 of [Fig. 2b] comprises a rotary friction welding machine such as that of [Fig. 2a], as well as an adaptive module 12. The adaptive module 12 is attached to the rotary member 6 of the rotary friction welding machine 100 of [Fig. 2a].

[0079] For example, the adaptive module 12 may be connected to the rotating member 6 via the attachment means 7 of [Fig.2a]. Alternatively, when the attachment means 7 of [Fig.2a] is removably connected to the rotating member 6, the attachment means may be removed and the adaptive module 12 may be connected directly to the rotating member 6.

[0080] The adaptive module 12 comprises a mechanism 13 for transforming a rotary movement into an alternating translational movement, for example a connecting rod-crank type mechanism. The adaptive module 12 further comprises a head 14 movable in translation fixed at the output of the mechanism 13. When the rotary member 6 is rotating relative to the axis 11, the movable head 14 is thus set in alternating translational movement in a direction orthogonal to the axis 11. The movable head 14 then performs a back-and-forth movement in a direction orthogonal to the axis of rotation of the rotary member 6.

[0081] The adaptive module 12 may further comprise or be connected to a fixing means 15, for example a clamp or a pliers, to temporarily fix a first mechanical part 1 to the movable head 14. When the rotary member 6 is rotated, the first mechanical part 1 is therefore set in reciprocating translational movement. The mechanical parts 1 and 2 can then be brought into contact to be assembled by linear friction.

[0082] The adaptive module 12 is therefore a module which can be mounted on a rotary friction welding machine 100, which makes it possible to transform the latter into a linear friction welding system 200. The adaptive module 12 therefore allows a user who has a rotary friction welding machine 100 to carry out linear friction welding without having to invest in a machine dedicated to linear friction.

[0083] In one or more embodiments, the linear friction welding system 200 may further comprise a computing module configured to determine, based on a target material consumption CM, a set of rotary friction welding parameters {er b er2, • • •, &r.n} for the system 200. This computing module implements a reverse pass function CM) = [erJ, er2, ..., • H is noted as the transition function gr( er2, ..., ) is different from the transition function er b er2, _, ), because the function f relates to a rotary friction welding process while the function Sr relates to a linear friction welding process (even if this is implemented by a rotary friction welding machine adapted to linear friction).

[0084] To determine this new passage function Sr, it is possible to exploit the knowledge acquired on rotary friction welding, contained in the passage function f . Indeed, by adding the adaptive module 12, new intermediate parameters are introduced, in particular the frequency and the amplitude of vibration of the moving head 14, which are significantly fewer in number than the welding parameters to be defined for a conventional linear rotation welding machine (such as the machine 300 shown in Figure 5a). Thus, the number of experiments that must be carried out to determine the passage function 8? is significantly reduced compared to the number of experiments that would be necessary to obtain the passage function of a new machine specifically dedicated to linear friction, because the number of “unknown” parameters which influence material consumption is considerably reduced.

[0085] Compared to a new welding machine specifically dedicated to a new friction mode (here, rotary friction), the adaptation of an already mastered welding machine to a new friction mode makes it possible to exploit to the maximum the feedback from the use of the already mastered machine by partially reapplying it to its variation on the new welding mode. To construct the new passage function 8r, it is appropriate to carry out a limited number of linear friction welding tests with predefined values ​​for the input parameters ^2, ■ • • ' er" of the rotary friction welding machine and to use the professional knowledge related to rotary friction.From this test plan, an influence relationship between rotary friction welding parameters and linear friction welding parameters can be quantified, and this relationship is reflected on the input parameters of the rotary friction welding machine, thus allowing it to be recalibrated under constraint to meet the requirements of the new linear friction welding process vis-à-vis the old rotary friction welding process.

[0086] Concretely, tests are carried out with fixed sets of input parameters ' e>v |a rotary friction welding machine, and the corresponding values ​​of the material consumption CM obtained at the end of the linear friction method are measured. The values ​​of the amplitude and the frequency of variation of the moving head 14 are also recorded. The passage function Sr is then calculated by modifying the passage function f from the values ​​of material consumption and amplitude / frequency of variation obtained.

[0087] Once the passage function 8r has been determined, it is its inverse function g~) which is used during a new welding process, because it provides all the parameters ' er'n to be applied to the rotary friction welding machine adapted to obtain a target CM value of material consumption: CM) =

[0088] This computer module may comprise a circuit, which may be for example a processor capable of interpreting instructions in the form of a computer program, an electronic card or even a programmable electronic chip such as an FPGA chip (for "Field-Programmable Gate Array" in English). The computer module may further comprise a memory for storing the Sr passage function. The computer module may further comprise an input interface for receiving data such as the materials, dimensions or characteristic values ​​of the geometry of the parts to be assembled, and an output interface for the provision of the welding parameter set. Finally, the computer module can be connected to a screen and a keyboard to allow easy interaction with a user.

[0089] [Fig. 3] represents a kinematic diagram of an adaptive module according to an embodiment of the invention. The diagram of [Fig. 3] is a conventional kinematic diagram of a connecting rod-crank type mechanism.

[0090] As shown in the kinematic diagram of [Fig. 3], the adaptive module 12 comprises, in one embodiment, a cylindrical part 31 provided with a guide pin 32 eccentric relative to the cylindrical part 31. By “eccentric”, it is understood that the guide pin 32 extends along an axis 34 which is parallel but different from the axis of rotation 33 of the cylindrical part 31. For example, the pin 32 can be connected to the (circular) surface 31a of the cylindrical part 31 at a point located at a non-zero distance from the center 31a of this surface 31a. It is noted that this distance can be advantageously variable, which makes it possible to adjust the vibration frequency of the moving head 14 of the adaptive module 12. The cylindrical part 31 can be attached to the rotating member 6 of the rotary friction welding machine 100 of [Fig.2a] as described previously.When the rotating member 6 of the rotary friction welding machine 100 is rotated, the cylindrical part is also rotated, for example along an axis parallel to the axis of rotation of the rotating member 6 of the rotary friction welding machine 100.

[0091] Of course, the cylindrical part 31 can be replaced by any rotating part, the cylindrical geometry being in no way limiting of the invention, similarly, the pin 32 is not necessarily cylindrical and can be of any geometry, with a head having a circular section (as shown in [Fig.4]).

[0092] The guide pin 32 is connected to a double bearing and ball rail system 35 itself connected to the vibrating head 14. The vibrating head 14 can advantageously be provided with two dampers at its ends. When the cylindrical part 31 is rotated, the vibrating head 14 is set in reciprocating translational motion. The first mechanical part 1 can then be fixed on the vibrating head 14. Thus, when the cylindrical part 31 is rotated (i.e. when the rotary friction welding machine 100 is put into operation), the first mechanical part 1 is set in reciprocating translational motion (in the example of [Fig.3], an reciprocating translational motion along an axis orthogonal to the axis of rotation of the cylindrical part 31).

[0093] The adaptive module 12 thus makes it possible to transform a rotational movement of the rotation member 6 of the rotary friction welding machine 100 - generated by the rotation of a large quantity of mass (inertial flywheels) - into an alternating translational movement. In addition, the vibration frequency of the movement of reciprocating translation of the movable head 14 (i.e. the frequency at which the movable head performs the reciprocating movement) can be advantageously adjusted by varying the rotation frequency of the rotation member 6 of the rotary friction welding machine 100 and / or the distance between one end of the pin 32 and the center 31b of the surface 31a of the cylindrical part 31.

[0094] The adaptive module 12 mounted on a conventional rotary friction means 100 then makes it possible to carry out linear friction, without having a machine specifically dedicated to linear friction.

[0095] It is noted that the distance between one end of the pin 32 and the center 31b of the surface 31a of the cylindrical part 31 (i.e. the eccentricity parameter of the pin 32) is a parameter that can be varied and which has an influence on the frequency and the speed of vibration of the moving head 14. Thus, this parameter is also an input parameter of the function Sr described above (and of the passage function S; described below).

[0096] In other words, to determine the passage function the tests are carried out with sets of input parameters ' er^ of the welding machine by fixed rotary friction and for a fixed pin eccentricity parameter value, and the corresponding values ​​of material consumption CM obtained after the linear friction process are measured. This means that Sr is a function of the rotary friction welding parameters • • ■ ' and the parameter of eccentricity d. The inverse function g'1 therefore provides the set of parameters er^ er,2? ■■■> er,n cl |a value eccentricity parameter d to be used to obtain a target value CM of material consumption gi CM ) = { er j, er% ern,d}-

[0097] [Fig.4] shows an adaptive module configured to be attached to a rotary friction welding machine according to one embodiment of the invention.

[0098] The adaptive module shown in [Fig.4] comprises a cylindrical part 31 and a guide pin 32 as previously described with reference to [Fig.3]. The guide pin 32 is eccentric relative to the center of a section of the cylindrical part 31. For example, the guide pin 32 can be fixed to the surface 31a of the cylindrical part 31, at a distance d (strictly positive and strictly less than the radius of the circular surface 31a) from the center 31b of the surface 31a. Advantageously, this distance d can be variable, in order to be able to vary the amplitude of the movement of the guide pin 32 when the cylindrical part 31 is rotating. For example, the surface 31a can comprise means for temporarily fixing the guide pin 32 at different distances d from the center 31b of the surface 31a of the cylindrical part 31.Such means may be, for example, a plurality of rods, for example threaded, arranged along a radius of the surface 31a of the cylinder 31. The . guide pin 32 may comprise, at its end, a hole (for example threaded) to be able to be fixed to one of the rods. Other means are conceivable, for example a fixing strip placed on the surface 31a of the cylindrical part 31 or a groove in the surface 31a of the cylindrical part 31, arranged along a radius of the surface 31a of the cylinder 31 and to which the guide pin 32 can be attached.

[0099] The adaptive module 13 may comprise, as shown in [Fig. 4], a frame 41 for holding the system in place when the rotary friction welding machine 100 is put into operation. This frame 41 may for example be placed or fixed (removably) on the base 10 of the rotary friction welding machine 100. The frame 41 is advantageously fixed when the rotary friction welding machine 100 is in operation.

[0100] A frame 42 can be mounted inside the frame 4L. On this frame 42 can be fixed the head 14 movable in translation. The frame 42 is advantageously movable in translation along an axis orthogonal to the axis of rotation of the cylindrical part (in [Fig. 4], the frame 42 is movable in translation along the y axis) and is driven in movement by the guide pin 32. For example, the frame 42 can comprise four panels, including an upper panel 42a, a lower panel 42b and two side panels (in [Fig. 4], only the side panel 42a is visible).

[0101] The guide pin 32 may include a head 32a located at an opposite end from the end connected to the cylindrical part 31, and the upper panel 42a and the lower panel 42b may grip the head 32a of the guide pin 32, so that the frame 42 moves inside the housing 41 when the cylindrical part 31 is rotating.More precisely, when the cylindrical part 31 is rotating, the guide pin 32 performs a circular movement which can be broken down into a vertical component (along the y axis) and a horizontal component (along the z axis) in the plane of the frame 4L. The horizontal component (along the z axis) causes the head 32a of the guide pin 32 to move in an alternating translational movement along the z axis inside the frame 41, and the vertical component (along the y axis) causes the head 32a of the guide pin 32 to move in an alternating translational movement along the y axis, driving the frame 41 - and therefore the head 14 - in the same alternating translational movement along the y axis.

[0102] It is noted that in [Fig.4], the head 32a of the guide pin 32 is cylindrical in shape with a radius greater than that of the body of the guide pin 32. This is of course not obligatory, and the dimension of the head 32a of the guide pin 32 could be equal to or less than that of the body.

[0103] To allow and / or facilitate the translational movements of the head 32a of the guide pin 32, the adaptive module can be provided with one or more guide systems, for example ball guides. Thus, the adaptive module 12 of [Fig.4] can comprises linear ball rails 43 (represented by horizontal plates and a set of circles) mounted on the lower 42b and upper 42a panels of the frame 42 to facilitate the movement of the head 32a of the guide pin 32 inside the frame 42 in the z direction. The head 32a of the guide pin 32 may also be provided with a ball bearing system (represented by circles around the head 32a of the pin 32). This double bearing system (ball bearing at the head 32a of the pin 32 and ball guide 43) makes it possible to limit as much as possible the friction between the different parts, which is preferable for systems like the one studied, the movements of the pin 32 being very rapid and the rotations and vibrations occurring at very high frequencies.

[0104] The adaptive module 12 may also include vertical linear ball rails 44 located between the frame 41 and the vertical panels 42c of the frame 42 to facilitate movement of the frame 42 relative to the frame 41 in the y direction.

[0105] Dampers 45, 46 may also be provided to dampen the movement of the frame 42 relative to the frame and / or the movement of the pin 32 relative to the frame 42. In particular, dampers 45 may be provided to dampen the movements of the ball rails 43 along the horizontal panels 42a, 42b of the frame 42 (in the z direction), and dampers 46 may be provided to dampen the movements of the frame along the frame 41 (in the y direction).

[0106] Of course, Figures 3 and 4 represent particular examples of an adaptive module of the invention, but can be replaced by any module capable of transforming a rotary movement into an alternating translational movement.

[0107] Figures 2, 3 and 4 relate to a first aspect of the invention, which relates to a rotary friction welding system adapted to perform linear friction welding. A second aspect of the invention relates to a linear friction welding system adapted to perform rotary friction welding, described below.

[0108] [Fig.5a] represents a linear friction welding machine according to the prior art.

[0109] The linear friction welding machine 300 shown in [Fig.5a] comprises a head 52 movable in translation (alternative) along a y axis. The head 52 movable in translation may be connected to an element 51 for setting in alternative translation movement comprising means (such as a vibrator) for setting in the head 52 movable in translation in alternative translation movement along the y axis. The movement element 51 may for example comprise a body fixed to a base 57, the body and the base 57 being fixed elements of the frame of the machine 100. Alternatively, the movement element 51 may be configured to move in translation parallel to the x axis (thus making it possible to approach the first mechanical part 1 to the second mechanical part 2). In this alternative, the movement element 51 may be configured to move in translation parallel to the x axis (thus making it possible to approach the first mechanical part 1 to the second mechanical part 2). movement 51 can for example be placed on a rail arranged on at least part of the surface of the base 57, parallel to the x axis.

[0110] The translationally movable head 52 comprises or is connected to a fixing means 53, for example a clamp or a pliers, for temporarily fixing a first mechanical part 1 to the translationally movable head 52. When the movable head 52 is set in reciprocating translational movement along the y axis, the first mechanical part 1 is thus also set in reciprocating translational movement along the y axis.

[0111] By "includes or is connected to", it is understood that the attachment means 53 may be a part of the moving head 52 (in which case the moving head 52 and the attachment means 53 form a single mechanical part), or may be mounted on the moving head 52, for example in a removably manner. In the case where the attachment means 53 is not a part of the moving head 52 but is removably connected to the moving head 52, it is still considered, for the purposes of the present invention, that the machine 300 without the attachment means 53 is a linear friction welding machine.

[0112] The machine 300 also comprises a guide member 54 capable of being moved in translation parallel to the x axis, so as to bring the second part 2 closer to the first mechanical part 1 to assemble the two mechanical parts 1, 2 by linear friction. The guide member 54 may for example be placed on a rail arranged on at least part of the surface of the base 57, parallel to the x axis.

[0113] The guide member 54 comprises or is connected to a fixing means 55, for example a clamp or a pliers, for temporarily fixing a second mechanical part 2 to the guide member 54. When the guide member 54 is set in translational movement along the x axis, the second mechanical part 2 is thus also set in translational movement along the x axis and can be brought closer to the first mechanical part 1.

[0114] It is noted that in certain embodiments, the guide member 54 can be connected to an intermediate part movable in translation along the y axis on which the fixing means 55 is mounted. In these embodiments, the second mechanical part 2 can also be put into reciprocating translational movement.

[0115] Similar to what was described with reference to Figure 2a, a passing function f? such that f(e^, ..., ejm) = CM, where m is a non-zero natural integer, £7 / , î = 1, ..., fîl is a linear friction welding parameter and CM is the material consumption during the welding process, can be defined. The index / here designates the fact that the pass-through function corresponds to a rotary friction welding process. This pass-through function can be implemented on a processor connected to the welding machine 300 or separate from the welding machine 300.

[0116] [Fig.5b] represents a rotary friction welding system according to a mode of realization of the invention.

[0117] In Figures 5a and 5b, the common elements have the same reference numerals. The system 400 of [Fig. 5b] comprises a linear friction welding machine such as that of [Fig. 5a], as well as an adaptive module 56. The adaptive module 56 is attached to the moving head 52 of the linear friction welding machine 300 of [Fig. 5a].

[0118] For example, the adaptive module 56 may be connected to the moving head 52 via the attachment means 53 of [Fig.5a]. Alternatively, when the attachment means 53 of [Fig.5a] is removably connected to the moving head 52, the attachment means 53 may be removed and the adaptive module 56 may be connected directly to the moving head 52.

[0119] The adaptive module 56 comprises a mechanism 57 for transforming an alternating translational movement into a rotary movement, for example a connecting rod-crank type mechanism. The adaptive module 56 further comprises a rotary member 58 fixed at the output of the mechanism 57. When the mobile head 52 is in alternating translational movement along the y axis, the rotary member 58 is thus rotated about an x ​​axis orthogonal to the y axis.

[0120] For example, the mechanism 57 for transforming an alternating translational movement into a rotary movement may be an “inverted” mechanism compared to that shown in Figures 3 and 4. By “inverted” it is understood that the translationally movable head 14 of the module 12 for transforming rotary movement into linear movement - which is therefore the “output” head of the module 12, to which the mechanical part 1 is connected in [Fig. 3] - becomes an “input” head, which makes it possible to mount the mechanism 57 for transforming an alternating translational movement into a rotary movement on the linear friction welding machine 300. Similarly, the cylindrical part 31, which was the “input” rotary member of the module 12 connected to the rotary friction welding machine 100, becomes the “output” rotary member, to which the mechanical part 1 to be welded is connected.

[0121] The adaptive module 56 may further comprise or be connected to a fixing means 59, for example a clamp or a pliers, to temporarily fix the first mechanical part 1 to the rotary member 58. When the movable head 52 is put into reciprocating translational movement (along the y axis in the example of [Fig.5b]), the first mechanical part 1 is therefore put into rotational movement (around the x axis in the example of [Fig.5b]). The mechanical parts 1 and 2 may then be brought into contact to be assembled by rotary friction.

[0122] The adaptive module 56 is therefore a module which can be mounted on a linear friction welding machine 300, which makes it possible to transform the latter into a rotary friction welding system 400. The adaptive module 56 therefore allows a user which has a 300 linear friction welding machine to perform rotary friction welding without having to invest in a dedicated rotary friction machine.

[0123] In one or more embodiments, the rotary friction welding system 400 may further comprise a computer module configured to determine, based on a target material consumption CM _ a set of linear friction welding parameters { and h • - - - £ / jn} for the system 400. This computer module implements a transition function g ( eii, 6 / 2, • • •, elm) = CM-

[0124] To determine this transition function 8^ it is possible to exploit the knowledge acquired on linear friction welding, contained in the transition function f}. Indeed, by adding the adaptive module 56, new intermediate parameters are introduced, linked to the rotation of the rotary member 58 (in particular its rotation speed), which are less numerous than all the welding parameters at the input of a conventional rotary friction welding machine (such as the machine 100). Thus, the number of experiments that must be carried out to determine the transition function Sr is significantly reduced compared to the number of experiments that would be necessary to obtain the transition function of a new machine specifically dedicated to rotary friction.

[0125] The passage function 8] is determined in a similar manner to the passage function 8r defined with reference to Figure 2b. Once this passage function Si has been determined, it is its inverse function which is used during a new welding process, because it provides the set of parameters ei'2, * ■ • ' 'A™ to be applied to the linear friction welding machine adapted to obtain a target value CM of material consumption: gj ( CM ) = { 6 / )b 6 / _2, ...,} •

[0126] The computer module may comprise a circuit, which may be for example a processor capable of interpreting instructions in the form of a computer program, an electronic card or even a programmable electronic chip such as an FPGA chip (for "Field-Programmable Gate Array" in English). The computer module may further comprise a memory for storing the passage function St. The computer module may further comprise an input interface for receiving data such as the materials, dimensions or characteristic values ​​of the geometry of the parts to be assembled, and an output interface for providing the set of welding parameters. Finally, the computer module may be connected to a screen and a keyboard to allow easy interaction with a user.

[0127] Of course, the present invention is not limited to the embodiments described above as examples; it extends to other variants. For example, the mechanism of [Fig.4] is provided for illustrative purposes and can be replaced by any mechanism for transforming a rotary movement into an alternating translational movement. According to another example, on the particular mechanism of [Fig.4], it is possible to optimize the profile of the head of the pin to have a better control of the vibration of the mobile head in translation. It is also possible to use a damping system of the mobile head in translation controlled dynamically by a system of electric or hydraulic cylinders.

Claims

Claims

1. An adaptive rotary or linear friction welding system, comprising: - a rotary friction welding device comprising a rotary member for rotating a mechanical part to be welded fixed to said rotary member when the device is used for rotary friction welding; and - a removable adaptive module comprising a motion transformation mechanism for transforming a rotary motion into an alternating translational motion, the motion transformation mechanism comprising a fixing mechanism for being connected to the rotary member of the rotary friction welding device, the adaptive module further comprising a translationally movable head fixed at the output of the motion transformation mechanism, so as to perform an alternating translational motion when the rotary member of the rotary friction welding device is rotated.

2. System according to claim 1, wherein the translationally movable head is provided with an element for fixing a first mechanical part to be welded to drive said first mechanical part to be welded in an alternating translational movement when the rotary member of the rotary friction welding device is rotated.

3. Adaptive linear or rotary friction welding system, comprising: - a linear friction welding device comprising a translationally movable head for putting into reciprocating translational movement a mechanical part to be welded fixed to said translationally movable head when the welding device is used to carry out linear friction welding; and - a removable adaptive module comprising a movement transformation mechanism for transforming an alternating translational movement into a rotary movement, the movement transformation mechanism comprising a fixing mechanism for being connected to the translationally movable head of the linear friction welding device, the adaptive module further comprising a rotary member fixed at the output of the movement transformation mechanism so as to be rotated when the translationally movable head of the linear friction welding device is put into reciprocating translational movement.

4. System according to claim 3, in which the rotary member is provided with an element for fixing a first mechanical part to be welded to drive said first mechanical part to be welded in a rotational movement when the translationally movable head of the linear friction welding device is put into reciprocating translational movement.

5. System according to one of the preceding claims, in which the rotary member is configured to rotate around a first predetermined axis, and in which the translationally movable head is configured to perform an alternating translational movement along a second predetermined axis, the first axis and the second axis being orthogonal.

6. System according to one of the preceding claims, in which the movement transformation mechanism is a connecting rod - crank type mechanism.

7. The system of claim 6, wherein the adaptive module comprises a rotating part to which a pin is fixed, the pin being eccentric relative to a surface of the rotating part, wherein the pin is connected by at least one mechanical connection to the translationally movable head so as to drive the translationally movable head in an alternating translational movement when the rotating part is rotated.

8. System according to one of the preceding claims, further comprising a computer module configured to: - receive a target material consumption value; - determine a set of input parameters of the welding device from the target material consumption value.

9. System according to the preceding claim, in which the determination of the set of input parameters of the welding device is carried out via a function translating a link between rotary friction welding parameters and linear friction welding parameters.

10. A system according to one of claims 8 and 9 in combination with one of claims 1 and 2, wherein the set of input parameters of the welding device comprises at least one of: a mass of the rotating member, a dimension of the rotating member, and a rotational speed of the rotating member.

11. System according to one of claims 8 and 9 in combination with one of claims 3 and 4, in which the set of input parameters of the welding device comprises at least one of: an amplitude of reciprocating translational movement of the translationally movable head and a frequency of reciprocating translational movement of the translationally movable head.

12. System according to one of claims 8 to 11 in combination with claim 7, wherein the set of input parameters of the welding device further comprises an eccentricity value of the pin relative to the surface of the rotating part.

13. System according to one of claims 8 to 12, wherein the computer module is further configured to receive a value of a geometric parameter and / or a value of a mechanical parameter of a mechanical part to be welded, wherein the set of input parameters of the welding device is further determined from the value of the geometric parameter and / or the value of the mechanical parameter of the mechanical part to be welded.

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