Machine tool

Abstract

The present invention relates to a machine tool (M) comprising a frame (100) and at least one positioning module (P) for positioning a rotary working spindle (200), the positioning module (P) moving the rotary working spindle (200) relative to the stationary frame (100) via a plurality of links. The machine tool is characterized in that the pivot links on the plurality of axes are each mounted by two bearings. The axes of the different links and the elements mounting the links are arranged in a specially designed manner, and the masses of the different components are substantially defined and distributed in such a way that the reduction gears of the motors of the first and second pivot links are preloaded by the resulting overhang. Each axis of the pivot links is provided with two measurement systems, and position measurement feedback from a closed-loop servo is provided by a position encoder arranged behind the reduction gear.

Description

Technical Field

[0001] The present invention relates to the field of machine tools, particularly to the field of machining tools, and more specifically to the adaptation of the kinematic structure of machine tools used for operations requiring high rigidity.

Background Art

[0002] Among the articulated structures that can be used to move a spindle carrying a machining tool, there is an articulated structure called an articulated arm well-known in the field of robotics.

[0003] These structures offer many advantages, but they also lack the rigidity and precision required for certain machining operations. Thus, for example, Chinese Patent No. 110802465 in the literature proposes an automatic deburring device having seven motion axes, but its rigidity and precision performance make it impossible to assume machining operations of these workpieces within the tolerances and quality ranges required for prismatic workpieces.

[0004] To solve these problems, the applicant has devised the structure proposed in European Patent No. 3487667 in the literature. This literature describes a machining machine tool having a kinematic structure for moving an electric spindle in a plane perpendicular to the axis of the electric spindle. Also, the kinematic structure is an articulated structure comprising two arms articulated to a plate along a rotation axis parallel to the axis of the electric spindle, and it is noteworthy that the second end of the second arm houses the electric spindle and the translation of the workpiece towards the electric spindle tool in a linear motion parallel to the axis of the electric spindle is ensured by a workpiece support module or by a plate support module.

[0005] The architecture of this machine tool is particularly advantageous in that it provides a multi-joint structure of two arms in order to perform the movement of the electric spindle in a plane perpendicular to the rotation axis of the electric spindle. The multi-joint structure consisting of two pivoting arms is simpler than the conventional stacked structure and has a lower mounting cost.

[0006] The only movement along the linear axis is the relative translation between the workpiece and the tool parallel to the axis of the electric spindle, which corresponds to the plunge movement.

[0007] This plunge movement is carried out either by a movement module associated with a workpiece support module in which the plate is fixed to the translational movement, or by a movement module associated with a plate in which the workpiece is fixed to the translational movement during machining.

[0008] Therefore, the present invention is not only the result of reducing the number of moving axes of the robot-type multi-axis multi-joint structure, but also the result of the selection and distribution between the positioning axis implemented by the multi-joint structure and the working axis implemented by the translational movement. Therefore, the proposed kinematic structure does not include redundant movements.

[0009] Reducing the number of moving axes saves the associated means for movement and reduces the uncertainty of positioning.

[0010] It is not the multi-joint structure but the axis under the workpiece or the plate that executes the axial machining force (drilling, tapping, etc.).

[0011] The use of the multi-joint structure has also made it possible to expand the window in which machining can be performed. In addition, the multi-joint structure can move outside the window, and tool change, maintenance, machining in different zones, It becomes easy to perform a plurality of operations such as the retraction of a machining unit for loading or unloading bulging parts, etc.

[0012] This machine tool configuration is open and has a larger access area, Positioning of the tool magazine, Integration of the tool magazine, Positioning of the tool change point, Selection of the method for exchanging tools, Positioning of the plate, Juxtaposition of a plurality of machine tools conforming to the present invention, Options for accommodating a robotic carriage that can operate within or near the machining area, and the carrying of tools for performing different functions, provide high flexibility.

[0013] Such a configuration makes it possible to define a new zone, but the electric spindle of a conventional machine tool customarily moves within the range of its machining zone. The articulated structure of the machine tool of the present invention enables the electric spindle to cross or exit outside the machining zone.

[0014] Nevertheless, this selection of articulated movement and stroke limits the use of such machine tools and thus restricts commercial utilization.

[0015] European Patent No. 3310528 of another document describes a machine tool for machining a workpiece, which includes a spindle arm having a spindle for receiving a tool or a workpiece, and is movably attached to a spindle arm receiving section disposed on a machine frame. The spindle arm is hinged to the spindle arm receiving section, designed as a longitudinal element, and pivotable about a first axis of rotation with respect to the spindle arm receiving section, including a first spindle arm section; and a second spindle arm section hinged to the first spindle arm section, designed as a longitudinal element, and pivotable about a second axis of rotation with respect to the first spindle arm section. The spindle arm receiving section includes a first sub-section and a second sub-section disposed on the machine frame at a distance from each other for receiving the spindle arm. The first sub-section of the spindle arm receiving section has a first braced drive for transmitting a first torque to the first spindle arm section. The first spindle arm section includes a first sub-section and a second sub-section disposed on the spindle arm receiving section at a distance from each other for receiving the second spindle arm section. The first sub-section of the first spindle arm section has a second braced drive for transmitting a second torque to the second spindle arm section.

[0016] This document does not describe how to achieve the rigidity and accuracy required for high-quality machining. Similar to the previous document, it is known that using double bearings for each pivot link contributes to this purpose. However, the need to transmit torque, as described above, can prevent the achievement of the rigidity required to achieve the desired accuracy.

[0017] In addition, similar to the previous document, the multi-joint movement and the number of axes of movement are limited.

[0018] European Patent No. 3290163 of another document describes a machine tool for machining a workpiece and a spindle carrier assembly for use on such a machine tool. This machine tool includes a machine frame, a clamping section disposed on the machine frame for clamping the workpiece to the machine tool, a rotary arm receiving section disposed on the machine frame, a first rotary arm pivotally mounted to the receiving section so as to be capable of pivoting about a first axis of rotation, a second rotary arm pivotally mounted about a second axis of rotation, a spindle support arm mounted to the second pivoting arm so as to be capable of rotating about a third axis of rotation, a milling head mounted to the spindle support arm so as to be capable of rotating about a fourth axis of rotation, and a working spindle held by the milling head for receiving a tool, and the third axis of rotation is oriented perpendicular or transverse to the fourth axis of rotation.

[0019] Although the limitation of its movement range is less, the layout of various sub-assemblies of this machine tool and their dimensional settings lead to an unbalanced structure with lower achievable rigidity and accuracy, and thus it seems economically infeasible for specific machining operations.

Summary of the Invention

[0020] The applicant of the present application conducted an investigation with the aim of proposing a machine tool having optimized characteristics, particularly for machining with multi-joint arms.

[0021] The machine tool of the present invention includes a frame and at least one positioning module for positioning a rotary working spindle, and the positioning module includes the following links to ensure the movement of the rotary working spindle relative to the fixed frame: - A sliding link for horizontal translational movement of the carriage relative to the frame along a first axis of the carriage, - A first pivoting link for rotational movement of a first arm relative to the carriage along a second axis parallel to the first axis, - A second pivot link for rotational movement along a third axis parallel to the first two of the second arm with respect to the first arm, - A third pivot link for rotational movement along a fourth axis located in a plane perpendicular to the first three axes, - A fourth pivot link for rotational movement of a rotary working spindle support along a fifth axis perpendicular to the fourth axis, is implemented, The implementation forms of the pivot links along the fourth and fifth axes are executed by a sub-assembly known as a list, The rotary working spindle rotates the tool along a sixth axis perpendicular to the fifth axis.

[0022] In this machine tool, the pivot links on the second axis, the third axis, and the fifth axis are each implemented by two bearings, and the main bearing and the secondary load-absorbing bearing are spaced apart from each other, The fourth axis of the third pivot link is positioned within the median plane defined between two bearings that guide the rotation of the pivot link along the third axis, Each of these pivot links is driven by a gear motor consisting of a motor and a reduction gear, The masses of the various components are defined and distributed in such a way that the reduction gears of the motors of the first and second pivot links are preloaded by the resulting overhang, The machine tool is controlled by a control unit associated with a variable-speed drive for processing a closed-loop servo loop for each axis of the pivot link, Each axis of the pivot link is equipped with two measurement systems, and position measurement feedback from the closed-loop servo is provided by a position encoder arranged behind the reduction gear, providing position measurement for the closed loop of the position servo, Position measurement feedback from the encoder located behind the reduction gear is carried out in the variable-speed drive, It is noteworthy that the sixth rotational axis of the tool moves within the plane of movement passing through the fourth axis of the third pivot link.

[0023] These features are implemented in combination with the dimensional settings of the various subassemblies to ensure high rigidity. To achieve this purpose, the various subassemblies are dimensioned to achieve a static rigidity (static support rigidity between the rotating work spindle and the frame) exceeding 10 N / μm. Specifically, the static rigidity of a robot with articulated continuous kinematics is less than 1 N / μm.

[0024] Therefore, this mechanical dimensional setting, the load-bearing bearings of the second, third, and fifth rotational axes, two measurement systems per axis, the combination of bearings of the linear axes, and the two articulated arms support two rotational axes that form a list, which is a reduced arm length, the maximum rigidity of the gear motor due to the preload provided by the weight of the equipment overhanging into the working area, enable position control to be ensured directly and individually for the moving parts behind the reduction gear by the dynamic transmission between the motor and the moving parts on the second and third axes, by the position feedback measured by the second encoder, and provide a stability limit that enables a sufficiently high position gain for optimal trajectory tracking.

[0025] This design enables the rotating work spindle to achieve a static rigidity exceeding 10 N / μm in the accessible working area between the tool and the frame, improve the working quality, improve the positioning accuracy.

[0026] Improve the drilling and milling capabilities in aluminum.

[0027] Such a machine tool design also achieves a high jerk with respect to the positioning path (the derivative of the acceleration vector with respect to time - i.e., the third derivative of the position vector with respect to time), i.e., 100 m / s 3 as well.

[0028] The integration of the second encoder of the positioning loop combined with a high jerk enables the high rigidity obtained by the structure, an essential feature for achieving high quality, and the accuracy of the operations performed.

[0029] The high kinematic rigidity enables the positioning of the encoder of the position servo loop on the moving parts after the reduction gear. The orientation of the arm in the working area generates a preload on the reduction gear associated with the first pivoting link, and thus is designed to increase its rigidity as the inertia with respect to the axis increases. This keeps the ratio of rigidity to inertia constant and high, ensuring optimal position servo performance throughout the working area. Thanks to this rigidity, a sufficiently high natural frequency is obtained on the first pivoting link, enabling position control and more dynamic behavior on the second encoder. This is because the position information from the second encoder is returned directly to the variable speed drive (not to the numerical controller) for the purpose of control in the position servo loop.

[0030] In addition, these performances make it possible to approximate as closely as possible a theoretical model or transformation that can be calculated by mathematical tools or software integrated into the control unit of the machine tool. The use of this numerical control transformation simplifies / eliminates the mechanical adjustment for the geometric shapes of the various axes.

[0031] In a preferred embodiment, the first encoder measures only the speed.

[0032] According to another particularly advantageous feature of the present invention, the machine tool is provided with cables and hoses for supplying the energy required for the rotating working spindle, and the second arm and the wrist are provided with hollow cores for accommodating them.

[0033] This feature protects the cables and hoses from contamination by chips or cutting fluid and limits the risk of interference with the workpiece carrier assembly and / or the workpiece.

[0034] According to another particularly advantageous feature of the invention, the machine tool is provided with means for winding up cables and hoses on the fourth and fifth rotating axes so as to prevent the cables and hoses from being twisted during movement, thereby functioning only when the cables and hoses are bent, and thus improving their durability.

[0035] According to another particularly advantageous feature of the invention, a subassembly known as a turret forms an assembly with the rotary working spindle, the assembly comprising a motor and reduction gears associated with the fourth, fifth, and sixth axes, and being inserted and fixed into the second arm by means of an interface flange, thereby enabling the assembly to be easily assembled, disassembled, withdrawn from the rest of the machine, and reducing the time required for maintenance work.

[0036] This turret function also includes cables and hoses for supplying energy from the cable-carrying chain of the carriage that moves translationally along the first axis.

[0037] This second arm includes a cable winding system and has a sufficient cross-sectional area to enable the change of the cable winding diameter.

[0038] According to another particularly advantageous feature of the invention, the hollow core of the second arm houses a winding shaft and a concentric sleeve that defines the winding volume of a single sheath that bundles the cables and hoses, and the radius of curvature of the cables and hoses within the winding volume varies according to the rotation angle of the turret along the fourth axis.

[0039] According to another particularly advantageous feature of the invention, the turret subassembly is equipped with two bearings for mounting a pivot link along the fifth axis, the rotary working spindle rotating between these bearings, and the first bearing housing a gear motor through which a rotary joint axially passes for supplying hydraulic energy and pneumatic energy to the rotary working spindle.

[0040] Since the machine tool of the present invention is a machining machine tool, the hydraulic cable used is a high-pressure cable.

[0041] According to another particularly advantageous feature of the present invention, the second bearing of the turret subassembly is integral with the rotary working spindle and is equipped with a winding device for the cables and hoses required for power supply and lubrication, and rotatably guides the rotating parts, whereby the radius of curvature of the cables and hoses varies as a function of the angular position of the rotary working spindle along the fifth axis.

[0042] According to another particularly advantageous feature of the present invention, the first arm includes a concave volume between the second and third rotation axes that allows an increase in the angular stroke of the second arm that can be accommodated in this concave portion in the retracted position. This design makes the positioning module extremely compact when retracted, frees up space for loading / unloading / transfer of parts, and optimizes the installation area of the machine (reduces the floor area).

[0043] According to another particularly advantageous feature of the present invention, the first arm has two ends, the first end is traversed by the second rotation axis, the second end is traversed by the third rotation axis, and the concave volume starts from the lower end and is defined in the retracted position so that the rear part of the rotary working spindle does not abut against the first arm.

[0044] The rotary spindle can project rearward with respect to the fifth rotation axis without hindering rotation along this axis in the retracted position.

[0045] Another particularly advantageous feature of the present invention is that the bearings supporting the second and third axes are symmetrical. This design enables the gear motors of these axes to be installed either on the right or left side. This provides the advantage that the installation area on one of the sides of the positioning module is reduced. This means that it is possible to select a variant of the positioning module (reduction of the installation area on both sides) to suit the layout constraints of the machine. This advantage is particularly interesting in a machine tool configuration having two working units sharing the same sliding surface.

[0046] This enables the minimum distance on the first axis between the two units, thanks to the gear motor being located "externally".

[0047] This symmetrical design can also be used to integrate additional drive devices or balance systems on the opposite side of the main spindle motor, for the purpose of increasing machining capacity, reducing energy consumption, or extending the service life of components (such as reduction gears).

[0048] According to another particularly advantageous feature of the present invention, the second arm is pre-formed such that the fourth axis of rotation intersects the fifth axis of rotation perpendicularly but does not intersect the third axis of rotation. By moving the fourth axis outwardly away from the third axis, the space occupied by the positioning module in the retracted position is optimized. By moving the fourth axis even further away, the stiffness of both arms is improved by avoiding the recess in the first arm from becoming too large while holding the large second arm for integrating the cable winding system.

[0049] According to another particularly advantageous feature of the present invention, the first arm has two ends, the first end being traversed by the second axis of rotation and the second end being traversed by the third axis of rotation, and the second end is equipped with two bearings for rotatably guiding the second arm along the third axis. When the second arm has two ends, the first end is traversed by a third axis of rotation, and the second end houses a list sub-assembly, The first end of the second arm is pre-formed to be received between two bearings fitted to the second end of the first arm.

[0050] According to another particularly advantageous feature of the invention, the first arm has two ends, the first end being traversed by a second axis of rotation and the second end being traversed by a third axis of rotation, When the second arm has two ends, the first end is traversed by a third axis of rotation, and the second end houses a list sub-assembly, The first end of the second arm is equipped with two bearings for rotatably guiding the second arm along the third axis, and the two bearings are spaced apart so as to be placed on both sides of the second end of the first arm.

[0051] This last configuration readily suggests the following features, namely that the second end of the first arm through which the third axis of rotation passes is equipped with two bearings for guiding the rotation of the second arm along the third axis, and that the gear motor is arranged between the two bearings at the second end of the first arm.

[0052] The relative arrangement of the bearings of the gear motor makes it more compact since it does not project beyond the volume of the articulated structure. The gear motor is also better protected.

[0053] According to another particularly advantageous feature of the invention, the translational movement along the first axis is effected using one of the following techniques - by a linear motor, - by a ball screw motor, - by a rack, is electrified.

[0054] A preferred combination of a gear motor for the axis of rotation and a linear motor for the translational axis - enables a very large modular stroke on the first axis, - Enable operations on long parts - Enable integration of multiple working modules for working on the same long part and / or multiple separate workstations.

[0055] According to another particularly advantageous feature of the present invention, the frame is pre-formed to accommodate two horizontal rails arranged parallel to the first axis of the translational movement and having an offset height, and the carriage is pre-formed to fit with the rails.

[0056] According to another particularly advantageous feature of the present invention, the translational movement along the first axis is electrified by a linear motor, and the frame has a vertical flat surface parallel to the rails and having a longitudinal axis designed to accommodate the secondary parts of the linear motor, and the flat surface is arranged higher than the rails and is laterally offset. The carriage is pre-formed to accommodate the primary parts of the linear motor.

[0057] According to another particularly advantageous feature of the present invention, the frame accommodates guide and drive elements along the first axis to - Facilitate transportation - Reduce transportation costs - Designed as a removable and juxtaposed long unit so as to be adaptable to customer requirements or the parts to be processed.

[0058] The position of the workpiece support relative to the frame is changeable.

[0059] In addition, the geometry of the frame guides the chips / waste liquid forward and facilitates their discharge.

[0060] With respect to the first axis, the positioning of the rails, motors, and rollers eliminates the need for a normal housing for kinematics, sliding surfaces, and linear measurement systems.

[0061] The machine tool of the present invention in terms of its compactness, generally the reduction of mass, particularly the moving mass, and the elimination of the need for frame cleaning by optimizing chip discharge, reduces the impact on the environment.

[0062] Although chip removal machining is the preferred main application envisaged for the machine tool of the present invention, - friction welding, - abrasive machining, it can also be used for other operations such as these.

[0063] Similarly, based on the same architecture but without using a rotating spindle, - additive manufacturing or 3D printing, - water jet machining, - electrical erosion, - laser beam machining or cutting, other applications such as these are envisaged.

[0064] The basic concepts of the present invention, as well as other details and features, described above in their most basic form, will become more clearly apparent by reading non-limiting examples of embodiments of the machine tool according to the present invention.

Brief Description of the Drawings

[0065]

Figure 1

Figure 2

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Figure 4

Figure 4a

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Figure 6

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Figure 9

Figure 10

Figure 11

Figure 12

Mode for Carrying Out the Invention

[0066] As shown in FIG. 1, the machine tool M generally includes a frame 100, a rotary work spindle, and in this case, a positioning module P for an electric spindle 200 that carries a tool 210.

[0067] The workpiece holder sub-assembly B is positioned in front of the frame 100 and is accompanied by a chip collection and removal sub-assembly C. The operator O can interact with the workpiece holder sub-assembly.

[0068] FIG. 2 shows the kinematic links implemented by the machine tool M. FIGS. 3 and 4 show the positioning module P alone.

[0069] As shown, the positioning module P is an articulated structure that moves the tool 210 relative to the fixed frame 100 by implementing a plurality of links only on six axes numbered A1 to A6.

[0070] For this purpose, the positioning module P comprises a carriage 300 that supports the articulated arms 400 and 500, at the end of which a turret subassembly 600 that houses the electric spindle 200 moves.

[0071] More specifically, the positioning module P implements the links described below.

[0072] The carriage 300 is slidably connected to the frame 100 for horizontal translational movement along the first axis A1. The movement is electrified by a linear motor 110.

[0073] The frame 100 is preformed to accommodate two horizontal rails 120 and 130 that are arranged parallel to the first axis A1 of the translational movement and have an offset height. The carriage 300 is preformed to fit with the rails 120 and 130 to implement a sliding link along the axis A1 and is equipped with guide shoes 310. The frame 100 has a longitudinal axis parallel to the rails 120 and 130 and comprises a vertical flat surface 140 that is designed to accommodate the secondary part 112 of the linear motor 110. The flat surface 140 is arranged higher than the rails 120 and 130 and is laterally offset.

[0074] The carriage 300 is preformed to accommodate the primary part 111 of the linear motor 110 (see Fig. 4a).

[0075] The advantage of this staggered rising arrangement is that the motor 110 is closer to the center of gravity of the positioning module P.

[0076] The carriage 300 is preformed to rotatably guide the first arm 400 along an axis A2 parallel to the axis A1. For this purpose, the carriage comprises two symmetrical bearings 320 and 330, between which the first end 410 of the first arm 400 rotates.

[0077] The first arm 400 is pre - formed at its second end 420 with two symmetrical bearings 430 and 440 in order to rotatably guide the second arm 500 along an axis A3 parallel to the axes A1 and A2. The first end 510 of the second arm 500 is interposed between the two bearings 430 and 440. This first arm 400 has a concave volume 450 between the axis A2 and the axis A3, enabling an increase in the angular stroke of the second arm 500 that can be accommodated within this concave surface in the retracted position shown in FIG. 4.

[0078] In addition, the concave volume 450 starts from the lower end 410 and is defined such that, as shown in FIG. 4a, in the retracted position, when the electric spindle 200 is oriented with its axis A6 intersecting the longitudinal axis of the arm 400, this concave volume prevents the rear part of the electric spindle 200 from abutting against the first arm 400 in the retracted position.

[0079] The second arm 500 employs a hollow tubular body and houses a list sub - assembly 600 at its second end 520, and the list sub - assembly implements a third electric pivoting link for rotational movement along an axis A4 perpendicular to the axes A1, A2, and A3, and - a fourth electric pivoting link for rotational movement of the electric spindle 200 along an axis A5 perpendicular to the fourth axis.

[0080] The electric spindle 200 rotates the tool 210 along an axis A6 perpendicular to the axis A5. The axis A6 of rotation of the tool 210 moves within a moving plane passing through the axis A4 of the third pivoting link.

[0081] The axis A4 of the third pivotal link coincides with the axis of the tubular body forming the second arm 500 and is positioned within the median plane defined between two bearings 430 and 440 that guide the rotation of the pivotal link along axis A3, within a plane that coincides with the first defined between two bearings 320 and 330 provided by the carriage 300. Thanks to the offset caused by the geometry of the end portion 510 that offsets the axis A4 corresponding to the axis of the tubular body of the second arm 500, the second arm 500 is pre-formed such that axis A4 intersects axis A5 perpendicularly and does not intersect axis A3.

[0082] These pivotal links are driven by a gear motor consisting of a motor and reduction gears.

[0083] As shown in FIGS. 5 and 9, the pivotal links on axes A2, A3, and A5 are each implemented by two bearings: a main bearing and a secondary bearing.

[0084] More precisely, as shown in FIG. 5, the pivotal link implemented between the lower end portion 410 of the arm 400 and the carriage 300 along axis A2 is guided by two bearings 320 and 330. The rotational drive device is implemented by a motor 321 associated with a reduction gear 322. This motor 321 is also associated with a first encoder 323 for speed measurement only.

[0085] The rotation driven part of the reduction gear 322 is attached to one side of the end portion 410 of the first arm 400 to transmit rotational motion. The bearing 320 that provides guidance on this side is closest to the motor 321 and is thus referred to as the main bearing.

[0086] The second side of the end portion 410 is equipped with an axial extension 331, which is rotatably guided by a second or secondary bearing 330 and is associated with a second encoder 332 for position measurement.

[0087] This also applies to the pivotal links of axes A3 and A5.

[0088] Thus, as also shown in the figure, the pivot link mounted between the upper end portion 420 of the arm 400 and the second arm 500 along the axis A3 is guided by two bearings 430 and 440. The rotary drive device is implemented by a motor 431 associated with a reduction gear 432. This motor 431 is also associated with a first encoder 433 for speed measurement only.

[0089] The rotation driven part of the reduction gear 432 is attached to one side of the end portion 510 of the second arm 500 so as to transmit the rotational movement. The bearing 430 providing guidance on this side is closest to the motor 431 and is thus called the main bearing.

[0090] The second surface of the end portion 510 is equipped with an axial extension 441, which is rotatably guided by a second or secondary bearing 440 and is associated with a second encoder 442 for position measurement.

[0091] Finally, as shown in FIG. 9, in order to guide the rotation of the electric spindle 200 in a plane perpendicular to the axis A5, the pivot link mounted along the axis A5 of the list 600 is guided by two bearings 610 and 620.

[0092] The rotary drive device is implemented by a gear motor 611.

[0093] This gear motor 611 is equipped with a first encoder for speed measurement only.

[0094] The rotation driven part of the gear motor 61 is attached to one side of the sleeve 220 that houses the electric spindle 200 in order to transmit the rotational movement along the axis A5. The bearing 610 providing guidance on this side is closest to the gear motor 611 and is thus called the main bearing.

[0095] A portion of the sheath 220 facing the opposite side of the portion mating with the gear motor 611 is pre-formed to be rotatably guided by a second or secondary bearing 620 and is associated with a second encoder 622 for position measurement.

[0096] The presence of the two encoders on these pivot links, one directly connected to the motor and the other placed in the drive chain after the movement of the reduction gear, makes it possible to implement the servo control device shown in FIG. 6.

[0097] As shown in FIG. 6, the machine tool is controlled by a CNC control unit 700, which processes servo loops with set points for each axis of the two-bearing swivel joint (including the single-bearing swivel joint for axis A4) described above. These set points are position 710, speed 720, and torque 730.

[0098] Each loop is equipped with a PID (proportional-integral-derivative) controller. Each PID is associated with a data input module that includes parameter set points and loop feedback data. The PIDs associated with their respective inputs form a sub-assembly called a variable speed drive.

[0099] As shown, the pivot link includes a motor M associated with the movement G of the reduction gear and two encoders E1 and E2. The first encoder E1 is only a speed encoder. The second encoder E2 is a position encoder representing the encoders 332, 442, and 622 described above. It is located after the movement G of the reduction gear and enables accurate feedback of the measured position for the closed-loop operation of the servo.

[0100] As shown, the position information from the second encoder downstream of the reduction gear is fed back via loop 710 to the digital control unit 700 upstream of the PID and processes the position setpoint. Thus, the speed of the motor is directly controlled to obtain the desired position without having to go through the numerical control unit.

[0101] As described above, it is the rigidity of various components that enables this type of position control.

[0102] By contributing to this rigidity and accuracy, the masses of the various components are defined and distributed in such a way that the reduction gears of the drive devices of the first and second pivot links on shafts A2 and A3 are each preloaded due to the formed overhang. In a preferred embodiment, these reduction gears are zero-backlash cycloids.

[0103] In a preferred embodiment, the third motor drive and the fourth reduction gear on shafts A4 and A5 are each driven harmonically.

[0104] These features prevent backlash of the reduction gears.

[0105] The machine tool M comprises a plurality of cables and pipes for supplying the energy required to operate the shafts and the electric spindle 200 and for transmitting commands and information. These cables and hoses are arranged in a coiled form so as to be subjected to bending stress rather than torsional stress during rotational movement.

[0106] As shown in FIG. 7, the tubular body constituting the second arm 500 is provided with a hollow core 530 to accommodate such a winding 540 (see FIG. 8) taking into account the rotation along shaft A4.

[0107] More precisely, the hollow core 530 of the second arm 500 houses a take-up shaft 550 and a concentric sleeve 560 that defines a take-up volume for a single sheath that bundles cables and pipes, and the radii of curvature of the cables and pipes within the take-up volume vary according to the rotation angle of the reel 600 along the fourth axis A4. The sleeve 560 limits the expansion of the take-up within the volume.

[0108] The take-up shaft 550 itself has a hollow core 551 with an opening 552 for a rotary joint that supplies the fluid power to clamp and unclamp the tool 210.

[0109] As shown in FIG. 9, the pivot link along axis A5 also houses a take-up device 630 that is slightly different in that each hose or cable is provided with a dedicated take-up roller.

[0110] In this way, the second bearing 620 of the reel subassembly 600 rotatably guides a rotating part that is integral with the sleeve 220 that houses the electric spindle 200. This rotating part is equipped with a take-up device 630 for the cables and hoses required for power supply and lubrication, whereby the radii of curvature of the cables and hoses vary according to the angular position of the electric spindle along axis A5.

[0111] Similarly, the rotary joint 614 (7 directions, based on the embodiment shown) passes axially through the gear motor 611 to supply hydraulic and pneumatic energy to the electric spindle 200.

[0112] As shown in FIGS. 7 and 8, a sub-assembly known as list 600 forms an independent unit together with the electric spindle 200 and together with the take-up shaft 550 and the take-up 540. This assembly is inserted and attached to the second arm 500 by an interface flange 570 attached to a mounting collar 580 fitted to the end 520 of the second arm 500. In this way, an assembly with various motors and gearboxes for shafts 4, 5, and 6 can be easily assembled, disassembled, and removed from the rest of the machine. It should be noted that the second encoder 571 is also attached (in addition to being fitted to the motor 572) to this pivot link along shaft A4.

[0113] According to the configuration shown in the previous figures, regarding the implementation form of the pivot link along shaft A3, the first end 510 of the second arm 500 was pre-formed to be accommodated between two bearings 430 and 440 fitted to the second end 420 of the first arm 400.

[0114] FIG. 10 shows a different configuration regarding the implementation form of the pivot link on shaft A3.

[0115] In this new configuration, the second arm 500' has two ends, namely, a first end 510' traversed by the third rotation axis A3 and a second end 520' that houses the so-called list sub-assembly 600'. The difference is that the first end 510' is equipped with two bearings 611' and 512' for rotatably guiding the second arm 500' along the third shaft A3. These two bearings 511' and 512' are spaced apart so as to be placed on both sides of the second end 420' of the first arm 400'.

[0116] The second end 420' of the first arm 400' through which the third rotation axis A3 passes is equipped with two bearings 430' and 440' for rotatably guiding the second arm 500' along the third axis A3. The gear motor 431' is located between the two bearings 430' and 440' at the second end 420' of the first arm 400'.

[0117] The symmetrical design of the carriage 100, the bearing of the shaft A2, and the first arm 400 integrating the bearing of the shaft A3 means that the gear motor for these shafts can be installed on either the right or left side. This provides the advantage of reducing the installation area on one of the sides of the positioning module. This means that a variant of the positioning module (reduction of the installation area on both sides) can be selected to suit the layout constraints of the machine. This advantage is particularly interesting in a machine configuration having two working units sharing the same sliding surface on the shaft A1. This enables the minimum distance on this shaft between the two positioning modules thanks to the gear motor being located "externally".

[0118] FIG. 12 shows such a configuration, where the two positioning modules P and P' can move towards each other without their respective drives colliding. Another feature shown by this figure relates to the frame, which is here designed as long removable and juxtaposed units 100a and 100b, enabling the accommodation of a plurality of positioning modules.

[0119] The symmetrical design can also be used to integrate an additional drive or a balance system on the opposite side of the main drive of the shaft for the purpose of increasing machining capacity, reducing energy consumption, or extending the service life of components (such as reduction gears), as shown in FIG. 11, where the second gear motor M2 is arranged on the opposite side of the first motor M1 on the symmetrical bearing 330, providing a rotational guide along the shaft A2.

[0120] It will be understood that the machining machine tool described and shown above has been described for purposes of disclosure and not of limitation. Of course, various arrangements, modifications, and improvements can be made to the above examples without departing from the scope of the present invention.

Claims

1. A machine tool (M) comprising a frame (100) and at least one positioning module (P) for positioning a rotary work spindle (200), wherein the positioning module (P) is linked to the following: - A sliding link for the horizontal translational motion of the carriage (300) along the first axis (A1) relative to the frame (100), - A first pivot link for the rotational motion of the first arm (400) relative to the carriage (300) along a second axis (A2) parallel to the first axis, - A second pivot link for rotational motion along a third axis (A3) parallel to the first two of the second arm (500) relative to the first arm (400), - A third pivot link for rotational motion along a fourth axis (A4) located in a plane perpendicular to the first three axes, - A fourth pivot link for the rotational motion of the rotating work spindle (200) support along a fifth axis (A5) perpendicular to the fourth axis (A4), By implementing this, the rotary work spindle (200) is moved relative to the fixed frame (100), The pivot links along the fourth axis (A4) and the fifth axis (A5) are implemented by a subassembly called a list (600), ensuring that the rotary working spindle (200) rotates the tool (210) along the sixth axis (A6) perpendicular to the fifth axis (A5). The pivot links on the second shaft (A2), the third shaft (A3), and the fifth shaft (A5) are each mounted by two bearings, with the primary bearing and secondary bearing spaced apart from each other. The fourth axis (A4) of the third pivot link is positioned in a median plane defined between the two bearings that guide the rotation of the pivot link along the third axis (A3), Each of these pivot links is driven by a gear motor consisting of a motor and a reduction gear. The masses of the various components are defined and distributed in such a way that the reduction gears of the motors of the first and second pivot links are preloaded by the resulting overhangs. The machine tool is controlled by a control unit associated with a variable-speed drive device for handling a closed-loop servo loop, for each axis of the pivot link. Each axis of the pivot link is equipped with two measuring systems, and position measurement feedback from the closed-loop servo is provided by a position encoder located after the reduction gear, providing the closed-loop position measurement of the position servo. The position measurement feedback from the encoder located after the reduction gear is performed in the variable speed drive device. The sixth rotation axis (A6) of the tool (210) moves in a plane of motion that passes through the fourth axis (A4) of the third pivot link. A machine tool (M) characterized by the fact that...

2. The machine tool (M) according to claim 1, characterized by the fact that the bearings (320, 330, and 430, 440) supporting the second shaft (A2) and the third shaft (A3) are symmetrical.

3. The machine tool (M) according to claim 1, characterized in that the second arm (500) is pre-formed such that the fourth axis of rotation (A4) intersects perpendicularly with the fifth axis of rotation (A5) but does not intersect with the third axis of rotation (A3).

4. The first arm (400) comprises two ends (410, 420), the first end (410) being traversed by the second axis of rotation (A2), the second end (420) being traversed by the third axis of rotation (A3), and the second end (420) being equipped with two bearings (430, 440) for rotatably guiding the second arm (500) along the third axis (A3), The machine tool (M) according to claim 1, characterized in that the second arm (500) has two ends, the first end (510) being traversed by the third pivot axis (A3), the second end (520) housing the list subassembly (600), and the first end (510) of the second arm (500) is pre-formed to be housed between the two bearings (430, 440) fitted to the second end (420) of the first arm (400).

5. The first arm (400') has two ends, the first end being traversed by the second rotation axis (A2), the second end (420') being traversed by the third rotation axis (A3), and the second arm (500') has two ends (510', 520'), the first end (510') being traversed by the third rotation axis (A3), and the second end (520') housing the list subassembly, and the second The machine tool (M) according to claim 1, characterized by the fact that the first end (510') of the arm (500') is equipped with two bearings (511', 512') for rotatably guiding the second arm (500') along the third axis (A3), and the two bearings (511', 512') are spaced apart so as to be mounted on both sides of the second end (420') of the first arm (400').

6. The machine tool (M) according to claim 1, characterized in that the first arm (400) has a concave volume (450) between the second rotation axis (A2) and the third rotation axis (A3) that allows for an increase in the angular advance of the second arm (500), which can be housed in the concave surface when retracted.

7. The machine tool (M) according to claim 1, characterized in that the list subassembly (600) together with the rotary working spindle (200) forms an assembly comprising the motor and the reduction gear associated with the fourth, fifth, and sixth axes, and is inserted into and secured to the second arm (500) by an interface flange (570), thereby allowing the assembly to be easily assembled, disassembled, and removed from the rest of the machine (M).

8. The machine tool (M) according to claim 1, characterized by the fact that it is provided with cables and hoses for supplying the energy required to the rotary working spindle (200), and the second arm (500) and wrist (600) are provided with hollow cores for housing them.

9. The machine tool (M) according to claim 8, further comprising means for winding up the cables and hoses on the fourth and fifth rotating shafts (A4 and A5) to prevent the cables and hoses from twisting during motion, characterized in that it functions only when the cables and hoses are bent.

10. The machine tool (M) according to claim 6, characterized in that the first arm (400) comprises two ends (410, 420), the first end (410) being traversed by the second rotation axis (A2), the second end (420) being traversed by the third rotation axis (A3), and the concave volume (450) starting from the lower end, and in the retracted position, the concave volume (450) is defined such as to prevent the rear of the rotary work spindle (200) from contacting the first arm (400).

11. The machine tool (M) according to claim 5, characterized in that the second end (420') of the first arm (400') through which the third rotation axis (A3) passes is equipped with two bearings for rotatably guiding the second arm (500') along the third axis (A3), and the gear motor (431') is positioned between the two bearings of the second end (420') of the first arm (400').

12. The machine tool (M) according to claim 8, characterized in that the hollow core of the second arm (500) houses a winding shaft (550) and a concentric sleeve (560) that defines a winding volume of a single sheath for bundling cables and pipes, and the radius of curvature of the cables and pipes within the winding volume changes according to the rotation angle of the list (600) about the fourth axis (A4).

13. The machine tool (M) according to claim 1, characterized in that the list subassembly (600) is equipped with two bearings (610, 620) for mounting a pivot link along the fifth axis (A5), the rotary working spindle (200) rotates between these bearings, and the first bearing houses a gear motor (611) through which a rotary joint passes axially in order to provide hydraulic and pneumatic power to the rotary working spindle (200).

14. The machine tool (M) according to claim 13, wherein the second bearing (620) of the list subassembly (600) is integrated with the rotary work spindle (200) and is equipped with a winding device (630) for the cables and hoses required for power supply and lubrication, rotatably guiding the rotating parts, characterized by the fact that the radius of curvature of the cables and hoses changes as a function of the angular position of the rotary work spindle (200) along the fifth axis (A5).

15. The machine tool (M) according to claim 1, characterized in that the frame (100) is preformed to accommodate two horizontal rails (120 and 130) arranged parallel to the first axis (A1) of translational motion and offset in height, and the carriage (300) is preformed to fit with the rails.

16. Translational movement along the first axis (A1) is performed using one of the following techniques: - By the linear motor (110), - By a ball screw motor, - By rack, The machine tool (M) according to claim 15, characterized by the fact that it is electrified.

17. The machine tool (M) according to claim 15, characterized in that translational movement along the first axis (A1) is motorized by a linear motor (110), the frame (100) has a vertical flat surface (140) having a longitudinal axis parallel to the rail and intended to accommodate a secondary component (112) of the linear motor (110), the flat surface (140) is positioned higher than the rails (120, 130) and offset laterally, and the carriage (300) is pre-formed to accommodate a primary component (111) of the linear motor (110).

18. The machine tool (M) according to any one of claims 15 to 17, characterized by the fact that the frame (100) is designed to house guide and drive elements along the first axis (A1) and to be a removable and juxtaposed long unit (100a, 100b).

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