Machine tool

Abstract

The invention relates to a machine tool (M), comprising a machine frame (100) and at least one positioning module (P) for positioning a rotating working spindle (200), which positioning module (P) moves the rotating working spindle (200) relative to the fixed machine frame (100) by means of a plurality of connections. The machine tool is characterized in that the pivoting connections on the plurality of shafts are each implemented by two bearings. The shafts of the different connections and the elements implementing said connections are arranged in a specially designed manner, the masses of the different components being substantially defined and distributed in such a way that the reduction gears of the motors of the first and second pivot connections are preloaded due to the resulting overhang. Each shaft of the pivot connection includes two measurement systems, wherein position measurement feedback from the closed loop servo is provided by a position encoder disposed behind the reduction gear.

Description

Technical Field

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

[0002] Among the articulated structures available for triggering the movement of the spindle carrying the machining tool, there are articulated structures called articulated arms, which are well known in the field of robotics.

[0003] Although these structures offer many advantages, they also lack the rigidity and precision required for certain machining operations. Thus, for example, document CN110802465 proposes an automatic deburring device with seven axes of movement, the rigidity and precision of which make it impossible to conceive of machining operations on prismatic workpieces within the tolerances and qualities required for these workpieces.

[0004] To solve these problems, the applicant has designed the structure proposed in document EP3487667, which describes a machining machine tool comprising a kinematic structure for triggering the movement of an electric spindle in a plane perpendicular to the axis of the electric spindle, and the machining machine tool is remarkable in that the kinematic structure is an articulated structure comprising two arms articulated with respect to a plate about a rotation axis parallel to the axis of the electric spindle, the second end of the second arm receiving the electric spindle, and the translation of the workpiece towards the electric spindle tool in a linear movement parallel to the axis of the electric spindle being ensured by a workpiece support module or a plate support module.

[0005] This machine tool architecture is particularly advantageous because it provides a two-arm articulated structure for implementing the movement of the electric spindle in a plane perpendicular to the axis of rotation of the electric spindle. The articulated structure composed of two pivoting arms is simpler and less costly to implement than a conventional stacked structure.

[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 transverse feed movement.

[0007] This transverse feed movement is implemented either by a movement module associated with the workpiece support module (in which case the plate is translationally fixed) or by a movement module associated with the plate (in which case the workpiece is translationally fixed during machining).

[0008] Therefore, the present invention is not only the result of reducing the number of axes of movement of a multi-axis articulated structure of the robot type, but also the result of the choice and distribution between the positioning axes implemented by the articulated structure and the working axes implemented by translational movements. Thus, the proposed kinematic structure has no redundant movements.

[0009] Reduces the number of axes of motion saved on the device related to triggering the motion and reduces the positioning uncertainty.

[0010] It is not the articulated structure that implements the axial machining forces (drilling, tapping, etc.), but the axis under the workpiece or the plate.

[0011] The use of the articulated structure also makes it possible to expand the window in which machining can be performed. In addition, the articulated structure can perform motions outside the said window and makes it easier for the machine tool to perform multiple operations, such as:

[0012] Tool change,

[0013] Maintenance,

[0014] Machining in different zones,

[0015] Retracting the machining unit to load or unload large-volume components,

[0016] etc.

[0017] This machine tool construction is open and has a large access area, providing great flexibility in the following aspects:

[0018] Positioning the tool magazine,

[0019] Integrating the tool magazine,

[0020] Positioning the tool change point,

[0021] The choice of how to change the tool,

[0022] Positioning of the plate,

[0023] Juxtaposition of multiple machine tools according to the present invention,

[0024] Options for accommodating an automated carriage that can operate in or near the machining area and carrying tools to perform different functions.

[0025] This construction makes it possible to define new zones, while the motor spindles of conventional machine tools usually move within their machining zones. The articulated structure of the machine tool according to the present invention allows the motor spindle to extend beyond or out of the machining zone.

[0026] However, this choice of articulated connection and stroke limits the use of this machine tool, thus limiting the commercial development of this machine tool.

[0027] Another document EP3310528 describes a machine tool for machining workpieces, which includes a spindle arm having a spindle for receiving a tool or a workpiece, and the spindle arm is movably attached to a spindle arm receiving section arranged on a machine frame. The spindle arm includes: a first spindle arm section, which is hinged to the spindle arm receiving section and is designed as a longitudinal element and can pivot relative to the spindle arm receiving section about a first rotation axis; a second spindle arm section, which is hinged to the first spindle arm section and is designed as a longitudinal element and can pivot relative to the first spindle arm section about a second rotation axis; the spindle arm receiving section includes: a first sub-section and a second sub-section, which are arranged on the machine frame at intervals from each other to receive the spindle arm, and the first sub-section of the spindle arm receiving section has a first supported drive device 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, which are arranged on the spindle arm receiving section at intervals from each other to receive the second spindle arm section, and the first sub-section of the first spindle arm section has a second supported drive device for transmitting a second torque to the second spindle arm section.

[0028] This document does not describe how the rigidity and precision required for high-quality machining can be achieved. As with the previous documents, it is known that using double supports for each pivot connection contributes to this purpose. However, the need to transmit the above torques may prevent obtaining the stiffness required to achieve the desired precision.

[0029] In addition, as with the previous documents, the number of joint axes and movement axes is limited.

[0030] Another document EP3290163 describes a machine tool for machining workpieces and a spindle support assembly for such a machine tool. The machine tool includes a machine frame, a clamping section arranged on the machine frame for clamping a workpiece to the machine tool, a slewing arm receiving section arranged on the machine frame, a first slewing arm pivotally mounted on the receiving section so as to be able to slewing about a first rotation axis, a second slewing arm pivotally mounted about a second rotation axis, a spindle support arm mounted on the second pivot arm so as to be able to rotate about a third rotation axis, a milling head mounted on the spindle support arm so as to be able to rotate about a fourth rotation axis, and a working spindle held on the milling head for receiving a tool, and the third rotation axis is oriented perpendicular or transverse to the fourth rotation axis.

[0031] Although there are fewer restrictions on the movement range of this machine tool, it seems that the layout of the various sub-assemblies of this machine tool and their dimensional design will result in an unbalanced structure, and the stiffness and precision of this unbalanced structure are lower than those of the achievable structure, so it is economically unfeasible for certain machining operations. Summary of the Invention

[0032] The Applicant has carried out research aimed at proposing a machine tool with optimized characteristics, in particular a machine tool for machining with an articulated arm.

[0033] The machine tool according to the invention comprises a frame and at least one positioning module for positioning a rotating working spindle, the positioning module ensuring the movement of the rotating working spindle relative to the fixed frame by implementing the following connecting elements:

[0034] - A sliding connecting element for horizontal translational movement along a first axis of a carriage relative to the frame,

[0035] - A first pivoting connecting element for the rotation of a first arm relative to the carriage along a second axis parallel to the first axis,

[0036] - A second pivoting connecting element for the rotation of a second arm relative to the first arm along a third axis parallel to the first two axes,

[0037] - A third pivoting connecting element for rotation along a fourth axis lying in a plane perpendicular to the first three axes,

[0038] - A fourth pivoting connecting element for the rotation of a rotating working spindle support along a fifth axis perpendicular to the fourth axis,

[0039] The specific implementation of the pivoting connecting elements along the fourth and fifth axes is carried out by a sub-assembly called a toggle joint,

[0040] A rotating working spindle that triggers the rotation of a tool along a sixth axis perpendicular to the fifth axis.

[0041] The machine tool is characterized in that the pivoting connecting elements on the second, third and fifth axes are each implemented by two supports: a main support and a secondary load-absorbing support spaced apart from each other,

[0042] The fourth axis of the third pivoting connecting element is positioned in the median plane defined between two supports that guide the rotation of the pivoting connecting element along the third axis,

[0043] Each of these pivoting connecting elements is driven by a gear motor consisting of a motor and a reduction gear,

[0044] 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 pivoting connecting elements are pre-loaded due to the resulting overhangs,

[0045] The machine tool is controlled by a control unit which, for each axis of the pivot joint, is associated with a variable-speed drive for processing a closed-loop servo circuit.

[0046] Each axis of the pivot joint includes two measuring systems, where the position measurement result feedback from the closed-loop servo mechanism is provided by a position encoder arranged after the reduction gear, thereby providing a position measurement result for the closed-loop of the position servo mechanism.

[0047] The position measurement result feedback from the encoder located after the reduction gear takes place at the variable-speed drive.

[0048] The sixth rotary axis of the tool moves in the plane of movement of the fourth axis through the third pivot joint.

[0049] These features are implemented in combination with the dimensional design of the various sub-assemblies to ensure high rigidity. For this purpose, the dimensions of the various sub-assemblies are designed to achieve a static stiffness (static support stiffness between the rotary working spindle and the machine frame) greater than 10 N / μm. As reference information, the static stiffness of a robot with articulated serial kinematics is less than 1 N / μm.

[0050] Therefore,

[0051] This mechanical dimensional design,

[0052] Load-absorbing supports on the second, third, and fifth rotary axes,

[0053] Two measuring systems for each axis,

[0054] The combination of a linear axis and two articulated arms carrying two rotary axes forming a toggle joint,

[0055] Enables:

[0056] A reduction in the arm length,

[0057] Due to the preload provided by the weight of the equipment overhanging into the working area, the gear motor has maximum stiffness,

[0058] The dynamic transmission between the motor and the moving parts on the second and third axes enables position control to be ensured with position feedback measured directly and only on the moving parts after the reduction gear by the second encoder, thereby providing a stability margin that allows a high enough position gain to achieve optimal trajectory tracking.

[0059] This design enables the rotary working spindle to achieve:

[0060] A static stiffness in the accessible working area between the tool and the machine frame greater than 10 N / μm,

[0061] Improved working quality,

[0062] Improved positioning accuracy,

[0063] Improved aluminum drilling and milling capabilities.

[0064] This machine tool design also achieves a high level of jerk (the derivative of the acceleration vector with respect to time, i.e., the third derivative of the position vector with respect to time) on the positioning path, namely 100 m / s 3 .

[0065] The integration of the second encoder in the positioning loop, combined with the high level of jerk, is made possible by the high stiffness obtained from this structure, which is a fundamental feature for achieving high quality and high precision in the operations to be performed.

[0066] The high kinematic stiffness makes it possible to position the encoder of the position servo loop on the moving part after the reduction gear. The orientation of the arm in the working area is designed to generate a preload on the reduction gear associated with the first pivot connection, thereby increasing the rigidity of the arm, the greater the inertia relative to the axis. This maintains a constant, high stiffness-to-inertia ratio, thus ensuring optimal position servo performance throughout the working area. Due to this rigidity, a sufficiently high natural frequency is obtained on the first pivot connection, enabling position control on the second encoder and achieving a more dynamic behavior. This is because the position information from the second encoder is returned directly to the variable speed drive (rather than to the digital controller) for control purposes in the position servo loop.

[0067] Furthermore, these performances make it possible to approach as closely as possible the theoretical model or transformation, which 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 of the geometry of the individual axes.

[0068] In a preferred embodiment, the first encoder only measures speed.

[0069] According to another particularly advantageous feature of the present invention, the machine tool includes cables and hoses for supplying the necessary energy to the rotating work spindle, and the second arm and the knuckle are provided with hollow cores to accommodate these cables and hoses.

[0070] This feature protects the cables and hoses from contamination by chips or cutting fluid and limits the risk of interference with the workpiece - support assembly and / or the workpiece.

[0071] According to another particularly advantageous feature of the present invention, the machine tool includes means for winding the cables and hoses on the fourth and fifth rotating axes, which are used to prevent these cables and hoses from twisting during movement, such that they only work when bent, thereby improving their durability.

[0072] According to another particularly advantageous feature of the invention, a subassembly called the toggle forms a component with a rotating working main shaft. A component including a motor and a reduction gear associated with a fourth axis, a fifth axis, and a sixth axis is inserted and fixed into the second arm by means of an interface flange, such that the component can be easily assembled, disassembled, and removed from the rest of the machine, thereby reducing the duration of maintenance operations.

[0073] This toggle function further includes cables and hoses for supplying energy to the cable carrier chain of the carriage that moves translationally along the first axis.

[0074] The second arm has a sufficient cross-section to accommodate a cable winding system and allows for changing the diameter of the cable winding.

[0075] 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 a winding volume for a single-sheath grouped cable and hoses. The curvature radii of these cables and hoses in this winding volume vary according to the rotation angle of the toggle along the fourth axis.

[0076] According to another particularly advantageous feature of the invention, the toggle subassembly is equipped with two supports for implementing a pivot connection along the fifth axis, and the rotating working main shaft rotates between these two supports. The first support houses a gear motor, and a rotary joint axially passes through the gear motor to supply hydraulic and pneumatic energy to the rotating working main shaft.

[0077] Since the machine tool of the invention is a machining machine tool, the hydraulic cables used are high-pressure cables.

[0078] According to another particularly advantageous feature of the invention, the second support of the toggle subassembly rotatably guides a rotating member that is integral with the rotating working main shaft and is equipped with winding devices for the cables and hoses required for power supply and lubrication, such that the curvature radii of the cables and hoses vary according to the angular position of the rotating working main shaft along the fifth axis.

[0079] According to another particularly advantageous feature of the invention, the first arm includes a concave volume between the second axis and the third rotating axis, which allows for increasing the angular stroke of the second arm. The second arm can be housed in this recess in the retracted position. This design makes the positioning module very compact when retracted, creates space for the loading / unloading / transfer components, and optimizes the footprint of the machine (reduced floor area).

[0080] According to another particularly advantageous feature of the invention, the first arm includes two ends, namely a first end traversed by a second rotation axis and a second end traversed by a third rotation axis, the concave volume starting from the lower end and being defined such that in the retracted position, this concave volume prevents the rear part of the rotating working spindle from abutting against the first arm.

[0081] The rotating spindle can project rearward relative to the fifth rotation axis without impeding rotation along this axis in the retracted position.

[0082] Another particularly advantageous feature of the invention is that the supports for the second and third axes are symmetrical. This design allows the gear motors for these axes to be mounted on the right or left side. This design offers the advantage of reducing the footprint on one of the sides of the positioning module. This means that you can choose the version of the positioning module (with reduced footprint on either side) to suit the layout constraints of your machine. This advantage is particularly notable in a machine tool configuration with two working units sharing the same slideway.

[0083] Due to the "external" position of the gear motors, this design allows for a minimum distance between the two units on the first axis.

[0084] This symmetrical design can also be used to integrate an additional drive or balancing system opposite the spindle motor, with the aim of improving machining capabilities, reducing energy consumption or extending the service life of components such as reduction gears.

[0085] According to another particularly advantageous feature of the invention, the second arm is preformed such that the fourth rotation axis intersects the fifth rotation axis perpendicularly without intersecting the third rotation axis. By moving the fourth axis outward away from the third axis, the space occupied by the positioning module in the retracted position is optimized. By moving the fourth axis further, the rigidity of the two arms is increased by avoiding excessive recesses in the first arm, while maintaining a large second arm to integrate the cable winding system.

[0086] According to another particularly advantageous feature of the invention, the first arm includes two ends, namely a first end traversed by a second rotation axis and a second end traversed by a third rotation axis, the second end being provided with two supports for rotatably guiding the second arm along the third axis,

[0087] The second arm includes two ends, namely a first end traversed by the third rotation axis and a second end accommodating the toggle subassembly,

[0088] The first end of this second arm is preformed to be received between the two supports assembled to the second end of the first arm.

[0089] According to another particularly advantageous feature of the invention, the first arm includes two ends, namely a first end traversed by a second rotation axis and a second end traversed by a third rotation axis,

[0090] The second arm includes two ends, namely a first end traversed by a third rotation axis and a second end that houses the toggle sub-assembly.

[0091] The first end of the second arm is provided with two supports for rotatably guiding the second arm along the third axis, the two supports being spaced apart so as to abut on either side of the second end of the first arm.

[0092] This last configuration makes it easier to conceive the following features, namely that the second end of the first arm through which the third rotation axis passes is provided with two supports for guiding the second arm to rotate along the third axis, and the gear motor is arranged between the two supports at the second end of the first arm.

[0093] The relative arrangement of the supports of the gear motor makes the machine tool more compact because it does not protrude beyond the volume of the articulated structure. The gear motor is also better protected.

[0094] According to another particularly advantageous feature of the invention, one of the following techniques is used to motorize the translation along the first axis:

[0095] - By means of a linear motor,

[0096] - By means of a ball screw motor,

[0097] - By means of a rack.

[0098] Preferred combination of a gear motor for the rotation axis and a linear motor for the translation axis:

[0099] - Allows a very large modular stroke on the first axis;

[0100] - Allows working on long parts;

[0101] - Makes it possible to integrate multiple working modules to work on the same long part and / or at multiple separate workstations.

[0102] According to another particularly advantageous feature of the invention, the frame is preformed to house two horizontal guide rails arranged parallel to the first translation movement axis and offset in height, and the carriage is preformed to cooperate with the guide rails.

[0103] According to another particularly advantageous feature of the invention, the translation along the first axis is motorized by means of a linear motor, and the frame includes a vertical flat surface having a longitudinal axis parallel to the guide rails and designed to house an auxiliary part of the linear motor, the flat surface being arranged above the guide rails and laterally offset,

[0104] The carriage is preformed to house the main part of the linear motor.

[0105] According to another particularly advantageous feature of the invention, the machine frame accommodates guide elements and drive elements along a first axis and is designed as a long unit that can be removed and juxtaposed in order to

[0106] - facilitate transportation,

[0107] - reduce transportation costs,

[0108] - be adaptable to customer requirements or parts waiting for processing.

[0109] The position of the workpiece support relative to the machine frame is adjustable.

[0110] Furthermore, the geometry of the machine frame guides chips / effluents to the front, thus facilitating their discharge.

[0111] For the first axis, the positioning of the guide rail, the motor and the scale eliminates the need for the common housings of kinematics, slides and linear measurement systems.

[0112] The environmental impact of the machine tool according to the invention is reduced due to:

[0113] its compactness,

[0114] the overall mass is reduced, especially the moving mass,

[0115] the need for cleaning the machine frame is eliminated by optimizing chip evacuation.

[0116] Although chip removal machining is the preferred main application envisaged for the machine tool according to the invention, it can also be used for other operations, such as:

[0117] - friction welding,

[0118] - grinding machining,

[0119] etc.

[0120] Similarly, based on the same architecture but without using a rotating spindle, other applications can be envisaged, such as:

[0121] - additive manufacturing or 3D printing,

[0122] - water jet machining,

[0123] - electro-erosion,

[0124] - laser beam machining or cutting,

[0125] etc.

[0126] By reading the non-limiting examples of the embodiments of the machine tool according to the invention, the basic concepts, other details and features of the invention, which have just been explained in their most basic form above, will become clearer. BRIEF DESCRIPTION OF THE DRAWINGS

[0127] Figure 1 is a schematic view of an overall perspective view of a machine tool according to an embodiment of the present invention;

[0128] Figure 2 is a kinematic diagram of the machine tool of the present invention;

[0129] Figure 3 is a schematic perspective view of the positioning module in the deployed position;

[0130] Figure 4 is a schematic perspective side view of the positioning module in the retracted position;

[0131] Figure 4a is a schematic perspective bottom view of the positioning module in the retracted position;

[0132] Figure 5 is a schematic cross-sectional view of a cross-section along the second and third axes passing through the first arm;

[0133] Figure 6 is an explanatory diagram of the operation of the position servo mechanism implemented by the machine tool of the present invention;

[0134] Figure 7 is a schematic top cross-sectional view of the second arm;

[0135] Figure 8 is a schematic perspective view of the toggle joint and the rotary work spindle assembly;

[0136] Figure 9 is a schematic view of a detailed cross-sectional view of a cross-section along the fifth and sixth axes passing through the free end of the positioning module;

[0137] Figure 10 is a schematic perspective view of a variant of the second arm;

[0138] Figure 11 is a schematic perspective view of a variant drive device of the first arm;

[0139] Figure 12 is a schematic perspective view of a machine tool structure including multiple positioning modules on a single frame. DETAILED DESCRIPTION OF THE INVENTION

[0140] As Figure 1 shown, the machine tool M generally includes a frame 100 and a positioning module P for rotating a work spindle, in this case, the rotating work spindle is an electric spindle 200 carrying a tool 210.

[0141] The workpiece fixture sub - assembly B is positioned in front of the frame 100 and is associated with the chip collection and removal sub - assembly C. The operator O can interact with the workpiece fixture sub - assembly.

[0142] Figure 2 The kinematic connectors implemented by the machine tool M are shown. Figure 3 and Figure 4 The positioning module P is shown separately.

[0143] As shown, the positioning module P is an articulated structure that triggers the movement of the tool 210 relative to the fixed frame 100 by implementing a plurality of connectors on only six axes numbered A1 to A6.

[0144] To this end, the positioning module P includes a carriage 300 that supports the articulated arm 400 and the articulated arm 500, and at the end of the carriage runs a knuckle sub - assembly 600 that houses the electric spindle 200.

[0145] More specifically, the positioning module P implements the connectors described below.

[0146] The carriage 300 is slidably connected to the frame 100 for horizontal translational movement along the first axis A1. The movement is motorized by means of a linear motor 110.

[0147] The frame 100 is pre - formed to house two horizontal guide rails 120 and 130 that are arranged parallel to the first axis A1 of the translational movement and are offset in height. The carriage 300 is pre - formed and is equipped with guide blocks 310 that cooperate with the guide rails 120 and the guide rails 130 in order to implement a sliding connector along the axis A1. The frame 100 includes a vertical flat surface 140 that has a longitudinal axis parallel to the guide rails 120 and the guide rails 130 and is designed to house an auxiliary part 112 of the linear motor 110. The flat surface 140 is arranged above the guide rails 120 and the guide rails 130 and is laterally offset.

[0148] The carriage 300 is pre - formed to house the main part 111 of the linear motor 110 (see Figure 4a ).

[0149] The advantage of this staggered, raised arrangement is that the motor 110 is closer to the center of gravity of the positioning module P.

[0150] The carriage 300 is pre - formed to rotatably guide the first arm 400 along an axis A2 parallel to the axis A1. To this end, the carriage includes two symmetric supports 320 and 330, and the first end 410 of the first arm 400 rotates between these two supports.

[0151] The first arm 400 is preformed at its second end 420 with two symmetrical supports 430 and 440 for rotatably guiding the second arm 500 along an axis A3 parallel to axes A1 and A2. The first end 510 of the second arm 500 is inserted between the two supports 430 and 440. The first arm 400 includes a concave volume 450 between axis A2 and axis A3, which allows an increase in the angular travel of the second arm 500, and the second arm can be accommodated in this recess in the retracted position shown in Figure 4 .

[0152] Furthermore, the concave volume 450 starts from the lower end 410 and is defined such that in the retracted position, the concave volume prevents the rear part of the electric spindle 200 from abutting against the first arm 400 when, in this retracted position, the electric spindle 200 is oriented such that its axis A6 intersects the longitudinal axis of the arm 400, as shown in Figure 4a .

[0153] The second arm 500 has a hollow tubular body and houses at its second end 520 a toggle subassembly 600 that implements:

[0154] - A third motorized pivot connection for rotational movement along an axis A4 perpendicular to axes A1, A2, and A3, and

[0155] - A fourth motorized pivot connection for rotational movement of the electric spindle 200 along an axis A5 perpendicular to the fourth axis.

[0156] The electric spindle 200 rotates a cutting tool 210 along an axis A6 perpendicular to axis A5. The rotational axis A6 of the cutting tool 210 moves in the plane of movement of the axis A4 passing through the third pivot connection.

[0157] The axis A4 of the third pivot connection coincides with the axis of the tubular body forming the second arm 500 and is positioned in the median plane defined between the two supports 430 and 440 that guide the rotation of the pivot connection along axis A3, and is positioned in a plane that coincides with the first one defined between the two supports 320 and 330 provided by the carriage 300. The second arm 500 is preformed such that axis A4 intersects axis A5 perpendicularly without intersecting axis A3, due to an offset resulting from the geometry of end 510, which offsets axis A4 corresponding to the axis of the tubular body of the second arm 500.

[0158] These pivot connections are driven by gear motors composed of a motor and a reduction gear.

[0159] As shown in Figure 5 and Figure 9 , the pivot connections on axes A2, A3, and A5 are each implemented by two supports: a main support and a secondary support.

[0160] More precisely, as Figure 5 shown, the pivot connection implemented between the end 410 of the arm 400 and the bracket 300 along the axis A2 is guided by two supports 320 and 330. The rotational drive is implemented by means of a motor 321 associated with a reduction gear 322. The motor 321 is also associated with a first encoder 323 used only for speed measurement.

[0161] The rotational drive part of the reduction gear 322 is attached to one side of the end 410 of the first arm 400 to transmit the rotational movement. The support 320 providing the guidance on this side is called the main support because it is closest to the motor 321.

[0162] The second side of the end 410 is provided with an axial extension 331 which is rotatably guided by the second or secondary support 330 and is associated with a second encoder 332 for position measurement.

[0163] This also applies to the pivot connections for the axes A3 and A5.

[0164] Thus, again as shown, the pivot connection implemented between the upper end 420 of the arm 400 and the second arm 500 along the axis A3 is guided by two supports 430 and 440. The rotational drive is implemented by means of a motor 431 associated with a reduction gear 432. This motor 431 is also associated with a first encoder 433 used only for speed measurement.

[0165] The rotational drive part of the reduction gear 432 is attached to one side of the end 510 of the second arm 500 to transmit the rotational movement. The support 430 providing the guidance on this side is called the main support because it is closest to the motor 431.

[0166] The second side of the end 510 is provided with an axial extension 441 which is rotatably guided by the second or secondary support 440 and is associated with a second encoder 442 for position measurement.

[0167] Finally, as Figure 9 shown, the pivot connection implemented in the toggle 600 along the axis A5 to guide the electric spindle 200 to rotate in a plane perpendicular to the axis A5 is guided by two supports 610 and 620.

[0168] The rotational drive is implemented by means of a gear motor 611.

[0169] This gear motor 611 is equipped with a first encoder used only for speed measurement.

[0170] The rotary drive part of the gear motor 61 is attached to one side of the sleeve 220 that houses the electric spindle 200 to transmit rotational motion along the axis A5. The guiding support 610 provided on this side is called the main support because it is closest to the gear motor 611.

[0171] The part of the sheath 220 that is away from the part that mates with the gear motor 611 is preformed to be rotationally guided by the second or secondary support 620 and is associated with the second encoder 622 for position measurement.

[0172] There are two encoders on these pivot joints, one directly connected to the motor and the other arranged in the drive chain after the reduction gear kinematics mechanism, which enables the implementation of Figure 6 the servo control shown.

[0173] As Figure 6 shown, the machine tool is controlled by the CNC control unit 700, which processes the servo loop for each axis using the set values for the above two support pivot joints (and also the single support pivot joint for the axis A4). The set values are:

[0174] position 710,

[0175] speed 720, and

[0176] torque 730.

[0177] Each loop is equipped with a PID (Proportional-Integral-Derivative) controller. Each PID is associated with a data input module, including parameter set values and loop feedback data. The PIDs associated with their corresponding inputs form a subassembly called the variable speed drive unit.

[0178] As shown, the pivot joint includes a motor M associated with the reduction gear kinematic mechanism G 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 above-mentioned encoders 332, 442, and 622. The second encoder is located after the kinematic mechanism G of the reduction gear and can accurately feedback the measured position for the closed-loop operation of the servo mechanism.

[0179] As shown, the position information from the second encoder downstream of the reduction gear is fed back via the loop 710 to the digital control unit 700 upstream of the PID that processes the position set value. Therefore, the speed of the motor is directly controlled to obtain the desired position without having to go through the digital control unit.

[0180] As described above, it is the rigidity of various components that makes this type of position control possible.

[0181] To achieve this rigidity and precision, the masses of the various components are defined and distributed in such a way that, due to the overhangs formed, the reduction gears of the drive means of the first pivot connection and the second pivot connection on the shafts A2 and A3 respectively are preloaded. In a preferred embodiment, these reduction gears are zero-clearance cycloidal gears.

[0182] In a preferred embodiment, the reduction gears of the third motor drive means and the fourth motor drive means on the shafts A4 and A5 respectively are harmonic drives.

[0183] These features prevent play in the reduction gears.

[0184] The machine tool M includes a plurality of cables and conduits for supplying energy and transmitting the commands and information required for the operating shafts and the electric spindle 200. These cables and hoses are arranged in a coiled form such that, during the rotational movement, they are subjected to bending stresses rather than torsional stresses.

[0185] As Figure 7 shown, the tubular body forming the second arm 500 is provided with a hollow core 530 to accommodate such a winding 540 taking into account the rotation along the shaft A4 (see Figure 8 ).

[0186] More precisely, the hollow core 530 of the second arm 500 houses a winding shaft 550 and a concentric sleeve 560 which defines the winding volume for a single sheath grouping of cables and conduits, the radius of curvature of these cables and conduits in this winding volume varying according to the rotation angle of the toggle 600 along the fourth axis A4. The sleeve 560 limits the expansion of the winding in said volume.

[0187] The winding shaft 550 itself has a hollow core 551 in which a rotary joint 552 opens to supply the hydraulic power for clamping and unclamping the tool 210.

[0188] As Figure 9 shown, the pivot connection along the shaft A5 also houses a slightly different winding device 630 since each hose or cable has a dedicated winding roller.

[0189] In this way, the second support 620 of the toggle subassembly 600 rotatably guides a rotating part integral with the sleeve 220 housing the electric spindle 200. This rotating part is equipped with a winding device 630 for the cables and hoses required for power supply and lubrication such that the radius of curvature of said cables and hoses varies according to the angular position of the electric spindle along the shaft A5.

[0190] Similarly, the rotary joint 614 (a seven-way rotary joint based on the shown embodiment) axially passes through the gear motor 611 to supply hydraulic and pneumatic energy to the electric spindle 200.

[0191] As Figure 7 and Figure 8 shown, a sub - assembly called the toggle 600 forms an independent unit with the electric spindle 200 and with the winding shaft 550 and the winding 540. This assembly is inserted and attached in the second arm 500 by means of an interface flange 570 which is attached to an attachment collar 580 fitted to the end 520 of the second arm 500. In this way, an assembly including 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 a second encoder 571 (in addition to the encoder fitted to the motor 572) is also fitted to this pivot connection along axis A4.

[0192] According to the construction shown in the previous figures, for the embodiment of the pivot connection along axis A3, the first end 510 of the second arm 500 is pre - formed to be received between two supports 430 and 440 fitted to the second end 420 of the first arm 400.

[0193] Figure 10 Different constructions are shown with respect to the embodiment of the pivot connection on axis A3.

[0194] In this new construction, the said second arm 500' includes two ends, namely a first end 510' crossed by a third rotation axis A3 and a second end 520' which houses the so - called toggle sub - assembly 600'. The difference is that the first end 510' is equipped with two supports 611' and 512' to rotatably guide the second arm 500' along the third axis A3. These two supports 511' and 512' are spaced apart so as to rest on either side of the second end 420' of the first arm 400'.

[0195] The second end 420' of the first arm 400' through which the third rotation axis A3 passes is equipped with two supports 430' and 440' to rotatably guide the second arm 500' along the third axis A3. A gear motor 431' is located between the two supports 430' and 440' of the second end 420' of the first arm 400'.

[0196] The symmetrical design of the carriage 100, the support of axis A2 and the first arm 400 integrating the support of axis A3 means that the gear motors for these axes can be mounted on the right or left side. This design offers the advantage of reducing the footprint on one of the sides of the positioning module. This means that you can choose a version of the positioning module (with reduced footprint on either side) to suit the layout constraints of your machine. This advantage is particularly noticeable in a machine tool construction having two working units sharing the same slide on axis A1. Due to the "external" position of the gear motors, a minimum distance between the two positioning modules on this axis is allowed.

[0197] Figure 12 It shows a configuration in which two positioning modules P and P' can move towards each other without their respective drive devices conflicting. Another feature shown in this figure relates to the machine frame, which is designed here as a long unit 100a and 100b that can be removed and juxtaposed, thereby allowing multiple positioning modules to be accommodated.

[0198] This symmetric design can also be used to integrate an additional drive or a balancing system opposite the main drive device of the shaft, with the aim of improving machining capacity, reducing energy consumption, or extending the service life of components (such as reduction gears), as Figure 11 shown, where the second gear motor M2 is arranged on the symmetric support 330 opposite the first gear motor M1, thereby providing rotational guidance along the axis A2.

[0199] It should be understood that the machining machine tool described and shown above is described for the purpose of disclosure rather than 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), the machine tool comprising a frame (100) and at least one positioning module (P) for positioning a rotating working spindle (200), the positioning module (P) moving the rotating working spindle (200) relative to the fixed frame (100) by implementing the following connecting members: - A sliding connecting member for horizontal translational movement of the carriage (300) relative to the frame (100) along a first axis (A1). - A first pivoting connecting member for rotational movement of a first arm (400) relative to the carriage (300) along a second axis (A2) parallel to the first axis. - A second pivoting connecting member for rotational movement relative to the first arm (400) along a third axis (A3) parallel to the first two axes of a second arm (500). - A third pivoting connecting member for rotational movement along a fourth axis (A4) lying in a plane perpendicular to the first three axes. - A fourth pivoting connecting member for rotational movement of a support of the rotating working spindle (200) along a fifth axis (A5) perpendicular to the fourth axis (A4), the implementation of the pivoting connecting members along the fourth axis (A4) and the fifth axis (A5) being carried out by a sub-assembly called a toggle (600), the rotating working spindle (200) ensuring rotational movement of a tool (210) along a sixth axis (A6) perpendicular to the fifth axis (A5). It is characterized in that Each of the pivot connectors on the second axis (A2), the third axis (A3), and the fifth axis (A5) is implemented by two supports: a main support and a secondary support spaced apart from each other. The fourth axis (A4) of the third pivot connector is positioned in the median plane defined between the two supports that guide the rotation of the pivot connector along the third axis (A3). Each of these pivot connectors is driven by a gear motor, which consists 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 pivot connector and the second pivot connector are preloaded due to the resulting overhangs. The machine tool is controlled by a control unit, and for each axis of the pivot connector, the control unit is associated with a variable speed drive for processing a closed-loop servo loop. Each axis of the pivot connector includes two measurement systems, where the position measurement result feedback from the closed-loop servo mechanism is provided by a position encoder arranged after the reduction gear, thereby providing the position measurement result for the closed-loop of the position servo mechanism. The position measurement result feedback from the encoder located after the reduction gear occurs at the variable speed drive. The sixth rotation axis (A6) of the tool (210) moves in the plane of motion passing through the fourth axis (A4) of the third pivot connector.

2. The machine tool (M) according to claim 1, characterized in that The supports (320, 330 and 430, 440) supporting the second axis (A2) and the third axis (A3) are symmetric.

3. The machine tool (M) according to claim 1 or 2, characterized in that The second arm (500) is preformed such that the fourth rotation axis (A4) intersects the fifth rotation axis (A5) perpendicularly without intersecting the third rotation axis (A3).

4. The machine tool (M) according to any one of claims 1 to 3, characterized in that The first arm (400) includes two ends (410, 420), namely a first end (410) traversed by the second rotation axis (A2) and a second end (420) traversed by the third rotation axis (A3). The second end (420) is equipped with two supports (430, 440) to rotatably guide the second arm (500) along the third axis (A3). The second arm (500) includes two ends, namely a first end (510) traversed by the third rotation axis (A3) and a second end (520) accommodating the toggle subassembly (600). The first end (510) of the second arm (500) is preformed to be received between the two supports (430, 440) assembled to the second end (420) of the first arm (400).

5. The machine tool (M) according to any one of claims 1 to 3, characterized in that, The first arm (400') includes two ends, namely a first end traversed by the second rotation axis (A2) and a second end (420') traversed by the third rotation axis (A3). The second arm (500') includes two ends (510', 520'), namely a first end (510') traversed by the third rotation axis (A3) and a second end (520') that houses the toggle subassembly. The first end (510') of the second arm (500') is provided with two supports (511', 512') to rotatably guide the second arm (500') along the third axis (A3). The two supports (511', 512') are spaced apart so as to rest on either side of the second end (420') of the first arm (400').

6. The machine tool (M) according to any one of claims 1 to 5, characterized in that, The first arm (400) includes a concave volume (450) between the second rotation axis (A2) and the third rotation axis (A3). The concave volume allows an increased angular range for the second arm (500), and the second arm can be accommodated in the recess in the retracted position.

7. The machine tool (M) according to any one of claims 1 to 6, characterized in that, The toggle subassembly (600) forms a component with the rotary working spindle (200). The assembly including the motor and the reduction gear associated with the fourth axis, the fifth axis, and the sixth axis is inserted and fixed in the second arm (500) by means of an interface flange (570), such that the assembly can be easily assembled, disassembled, and removed from the rest of the machine (M).

8. The machine tool (M) according to any one of claims 1 to 7, characterized in that, The machine tool includes cables and hoses for supplying necessary energy to the rotary working spindle (200). The second arm (500) and the toggle (600) are provided with hollow cores to house the cables and hoses.

9. The machine tool (M) according to claim 8, characterized in that, The machine tool includes means for winding the cables and hoses on the fourth rotation axis (A4) and the fifth rotation axis (A5). The means prevent the cables and hoses from twisting during movement, such that they only operate when bent.

10. The machine tool (M) according to claim 6, characterized in that, The first arm (400) includes two ends (410, 420), namely a first end (410) traversed by the second rotation axis (A2) and a second end (420) traversed by the third rotation axis (A3). The concave volume (450) starts from the lower end and is defined such that in the retracted position, the concave volume (450) prevents the rear part of the rotary working spindle (200) from abutting against 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') traversed by the third rotation axis (A3) is provided with two supports for rotatably guiding the second arm (500') along the third axis (A3). The gear motor (431') is arranged between the two supports at the second end (420') of the first arm (400').

12. The machine tool (M) according to claim 8 or 9, 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 for a single sheathed grouped cable and conduit, and the radius of curvature of the cable and conduit in the winding volume varies according to the rotation angle of the toggle (600) about the fourth axis (A4).

13. The machine tool (M) according to any one of the preceding claims, characterized in that, The toggle sub-assembly (600) is provided with two supports (610, 620) for implementing the pivot connection along the fifth axis (A5), and the rotary working main shaft (200) rotates between the two supports. A first support houses a gear motor (611), and a rotary joint passes through the gear motor to supply hydraulic and pneumatic power to the rotary working main shaft (200).

14. The machine tool (M) according to claim 13, characterized in that, The second support (620) of the toggle sub-assembly (600) rotatably guides a rotating member that is integral with the rotary working main shaft (200) and is provided with a winding device (630) for the cables and hoses required for power supply and lubrication, such that the radius of curvature of the cables and hoses varies according to the angular position of the rotary working main shaft (200) along the fifth axis (A5).

15. The machine tool (M) according to any one of the preceding claims, characterized in that, The frame (100) is preformed to accommodate two horizontal guide rails (120 and 130) arranged parallel to the first axis of translation (A1) and offset in height, and the carriage (300) is preformed to cooperate with the guide rails.

16. The machine tool (M) according to claim 15, characterized in that, One of the following techniques is used to motorize the translation along the first axis (A1): - By means of a linear motor (110), - By means of a ball screw motor, - By means of a rack.

17. The machine tool (M) according to claim 15, characterized in that, The translation along the first axis (A1) is motorized by means of a linear motor (110), and the frame (100) includes a vertical flat surface (140) having a longitudinal axis parallel to the guide rails and intended to accommodate an auxiliary part (112) of the linear motor (110). The flat surface (140) is arranged above the guide rails (120, 130) and laterally offset, and the carriage (300) is preformed to accommodate a main part (111) of the linear motor (110).

18. The machine tool (M) according to any one of claims 15 to 17, characterized in that, The frame (100) accommodates guiding elements and driving elements along the first axis (A1) and is designed to be a long unit (100a, 100b) that can be removed and juxtaposed.

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