Workpiece processing system including a machine tool and corresponding processing method - Patents.com

Abstract

The present invention relates to a system and method for processing a workpiece (P1), which uses a machine tool (M1) including a drive shaft (400) with a tool holder (600) to which a tool (900) can be coupled, a drive motor (2) for rotating at least a portion of the drive shaft (400) engaged with the tool holder (600), and a feed motor (3) for axially moving the drive shaft (400). The apparatus measures a distance representing the distance between the workpiece (P1) and a machine tool frame (100). A control unit (8) is configured to perform processing operations on the workpiece by controlling the drive motor and / or the feed motor and to identify changes in the axial distance between the machine tool frame and the workpiece caused by the relative axial movement between the workpiece and the frame. A second motor is controlled to axially move the drive shaft to offset the relative axial movement between the workpiece and the frame.

Description

[Technical Field]

[0001] The present invention relates generally to workpiece processing systems including machine tools. [Background technology]

[0002] Machine tools are known in the art for performing, for example, milling, trimming, drilling, threading or nut-driving operations.

[0003] From DE 10 2004 014 14 A1 a drilling system is known which includes a clamp for holding a workpiece to be treated and a drilling machine which is configured to simultaneously impart linear and rotational movements to the drilling tool.

[0004] The drilling machine includes a first motor and a second motor, the first motor including a rotor coupled to a ball screw engaged with a helical ring on a drive shaft, converting rotational motion of the rotor into linear motion imparted to the drive shaft.

[0005] The second motor includes a rotor coupled to ball splines that engage splines on the drive shaft, transmitting the rotational motion of the rotor directly to the drive shaft while allowing the drive shaft to move linearly along its axis.

[0006] However, during this processing, the workpiece may move even while being held, and it may be desirable for the operator to avoid such movement. The workpiece may move backward during processing, for example, due to the tool pressing against the workpiece, which may reduce the quality of the processing performed on the workpiece. In particular, the dimensions obtained for the area of ​​the workpiece processed in this way may not correspond to the desired dimensions.

[0007] Patent Document 2 discloses a robot carrying a machine tool including a drilling tool. The drilling tool includes a shaft drill.

[0008] Patent Document 3 discloses a drilling / milling unit adapted to be supported by an industrial robot. The drilling / milling unit includes a spindle that rotates about an axis. An electric servo motor drives a hollow shaft axially via a belt. The electric servo motor drives the spindle via a connected belt. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] U.S. Patent No. 5,649,451 [Patent Document 2] GB Patent Application Publication No. 2593501 [Patent Document 3] US Patent Application Publication No. 2012 / 020756 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to provide a new machine tool and a corresponding processing method that can solve all or part of the above problems. [Means for solving the problem]

[0011] To this end, it is an object of the present invention to provide a workpiece processing system, the system including a machine tool, the machine tool comprising: The frame and a drive shaft having a longitudinal axis and provided with a tool holder to which a tool such as a drilling spindle can be coupled; a first motor, referred to as a rotary drive motor, configured to rotate at least a portion of a drive shaft coupled to the tool holder; a second motor, called a feed motor, configured to move the drive shaft axially, and preferably a linear motor; and The system further comprises: a distance measuring device configured to measure a distance representative of a distance between the workpiece and a frame of the machine tool; Control unit and Including, The control unit performing a processing operation on the workpiece by controlling the rotation drive motor to rotate the tool holder and / or by controlling the feed motor to move the tool holder axially; Using a distance measuring device, determine a change in the axial distance between the machine tool frame and the workpiece caused by relative axial movement between the workpiece to be processed and the machine tool frame; and controlling the second motor to move the drive shaft in the axial direction in response to a change in the determined distance between the frame of the machine tool and the workpiece to be processed to offset the relative axial movement between the workpiece and the frame of the machine tool; Furthermore, the rotary drive motor and the feed motor are characterized in that they are configured so that the axial movement of at least a portion of the drive shaft coupled to the tool holding portion can be controlled independently of the rotation of at least a portion of the drive shaft coupled to the tool holding portion.

[0012] The ability to control the axial movement of at least a portion of the drive shaft engaged with the tool holder independently of the rotation of at least a portion of the drive shaft engaged with the tool holder means that the rotation of at least a portion of the drive shaft does not affect the axial movement of the drive shaft, and vice versa, allowing the drive shaft to be precisely and reliably moved back and forth to move the drive shaft to a new axial reference position in response to movements of the workpiece being processed that must be compensated for.

[0013] The ability to control the axial movement of the drive shaft to which the tool holder is fixed during operation of the machine tool allows the position of the tool connected to the tool holder to be corrected, thereby maintaining the position of the tool holder relative to the workpiece being processed, and therefore the position of the tool relative to the workpiece being processed, even when there is relative axial movement between the workpiece being processed and the frame of the machine tool.

[0014] The relative axial movement between the tool and the workpiece being processed can be due to movement of the entire workpiece (e.g., movement of the workpiece backwards) or due to deformation of the workpiece being processed while it is being processed.

[0015] By taking into account variations in the relative position between the machine tool and the workpiece being processed, it is possible to ensure that the workpiece can be processed precisely and reliably.

[0016] Counteracting the relative axial movement between the machine tool and the workpiece being processed allows for, among other things, effective fragmentation of swarf resulting from the workpiece being processed by the tool. If the relative axial movement is not counteracted, this fragmentation may be poorly fragmented or may not even occur. Furthermore, counteracting the relative axial movement ensures that the milling depth is as desired.

[0017] In the conventional example of Patent Document 2, the drill is simply moved back and forth using its freedom of movement, but Patent Document 2 does not adjust the axial position of the drill relative to the machine tool frame to obtain a new reference position for the drill relative to the machine tool frame in order to offset the measured offset between the machine tool frame and the workpiece being processed.In Patent Document 2, the robot arm itself moves to offset the offset between the workpiece and the drilling machine tool carried by the robot arm.

[0018] Patent document 2 does not adjust the axial position of the drill relative to the frame of the machine tool to offset the measured deviation due to axial movement of the drill-carrying shaft relative to the frame, which can be controlled independently of the rotation of the drill-carrying shaft.

[0019] In Patent Document 2, in order to correct misalignment during drilling, the robot arm unit carrying the machine tool itself is moved, and moving the entire heavy robot arm unit is less precise than moving the drill relative to the frame with a feed motor, so there are problems with precision and reliability.

[0020] Furthermore, this movement of the robot arm part results in the movement of several axes of the robot, and the movement of the machine tool is not sufficiently collinear with the axis of the drilling being performed on the workpiece, thus adversely affecting the quality of the tool's processing.

[0021] The design of the system according to the present invention allows the position of a processing tool such as a drill to be corrected in real time, in a simple and reliable manner, while maintaining the drilling direction in the case of a drilling tool.

[0022] In Patent Document 3, a rotary motor rotates a spindle, and a speed difference between the rotary motor and another motor causes translation of the spindle. Therefore, the two operations of rotation and feed are not completely separated. For example, a slight change in the rotation speed of the rotary motor causes a slight translation of the spindle. Furthermore, in Patent Document 3, the feed operation is also dependent on a helical nut, and mechanical parts that can loosen may lead to axial alignment errors of the spindle, especially during the compensation operation.

[0023] The system design according to the invention allows the position of a tool coupled to a tool holder carried by a drive shaft to be corrected by movement of a single motor, i.e., a feed motor, thus maintaining and thus accurately and reliably correcting in real time the position of the tool holder relative to the workpiece, and hence the position of the tool relative to the workpiece, even when there is relative axial movement between the workpiece and the machine tool frame.

[0024] The system may also have one or several features taking into account any technically possible combination:

[0025] According to one embodiment of the present invention, the distance measuring device is carried by a movable part of the compression device called the blank holding part tip, the movable part of the blank holding part tip being mounted so as to be movable relative to a part fixed relative to the frame, the movable part being configured to compress the workpiece backward, and the distance measuring device being arranged to measure the distance between the movable part and the fixed part of the blank holding part tip.

[0026] According to one embodiment of the present invention, the drive shaft includes a first segment and a second segment connected to each other by a connecting device, one segment engaging with the feed motor and the other segment engaging with the rotary drive motor.

[0027] According to one embodiment of the present invention, the drive shaft includes a first segment and a second segment connected to one another by a connecting device configured to couple the first segment and the second segment together for axial movement while maintaining the first segment free to rotate relative to the second segment.

[0028] According to one embodiment of the present invention, the first segment, to which the tool holder is fixed, can be rotated by a rotary drive motor, and the second segment can be moved axially by a feed motor.

[0029] According to one embodiment of the present invention, the feed motor is a linear motor having a main section fixedly mounted relative to the frame of the machine tool and a secondary section mounted for movement parallel to the axis of the drive shaft, the secondary section being fixed to or formed integrally with a segment of the drive shaft.

[0030] According to one embodiment of the present invention, a system includes a support system, such as an articulated robot, carrying a machine tool, which is hingedly mounted to the support system to position the machine tool at a desired location and orientation relative to a workpiece to be processed.

[0031] According to one embodiment, the support system comprises a main base (or framework) and an arm section, the machine tool being hingedly mounted to the arm section, the arm section comprising one or several sections joined together by hinges, preferably the arm section being hingedly mounted to the main base.

[0032] According to one embodiment of the present invention, the control unit is configured to move the drive shaft to move the tool axially at a variable speed to fragment shavings resulting from the tool processing the workpiece.

[0033] The present invention further relates to a method for processing a workpiece using a processing system according to any of the embodiments described above, wherein a machine tool of the processing system includes a tool holder with a processing tool, the method comprising: positioning the machine tool relative to the workpiece with a view to processing the workpiece with the processing tool, the distance between the workpiece and the frame of the machine tool being equal to a value referred to as an initial value, and the drive shaft having an axial reference position relative to the frame of the machine tool; performing a processing operation on the workpiece by controlling the rotary drive motor to rotate the processing tool and / or by controlling the feed motor to axially move the processing tool, the axial movement of the processing tool being controlled as a function of an axial reference position of the drive shaft; determining a change in the distance between the workpiece and the machine tool frame during processing of the workpiece and causing the distance between the workpiece and the machine tool frame to equal the new value; offsetting the movement of the workpiece due to the axial movement of the drive shaft of the tool holder by a distance corresponding to the difference between the new value and the initial value, referred to as an offset distance, to define a new axial reference position of the drive shaft; continuing the processing operation on the workpiece as a function of the new reference position of the shaft; A workpiece processing method including the steps of:

[0034] According to certain aspects, to compensate for workpiece movement, the frame of the machine tool carrying the motor is kept stationary in the Earth reference frame while the drive shaft moves axially, so that the drive shaft moves, preferably along and within the frame of the machine tool, rather than the frame moving, which may be moved in the Earth reference frame.

[0035] According to one embodiment of the present invention, the rotary drive motor includes a stator mounted fixedly relative to the frame of the machine and a rotor directly engaged with the drive shaft.

[0036] Preferably, the stator includes a winding system and the rotor includes a magnet system to apply power to the winding system to generate a magnetic field that interacts with the magnet system. Thus, the rotary motor generates a radial electromotive force (electromagnetic torque) that rotates at least a portion of the drive shaft engaged by the rotor. The electromotive force generated by the feed motor is axial, while the electromotive force generated by the rotary motor is radial.

[0037] Advantageously, the sub-portion of the feed motor directly engages the drive shaft.

[0038] Preferably, the main part of the feed motor includes a winding system carried by the frame, and the secondary part of the feed motor includes a magnet system integrated with or directly incorporated into the drive shaft, powering the winding system generates a magnetic field that interacts with the magnet system.

[0039] The feed motor generates an axial electromotive force that translates the drive shaft to which the feed motor subsection is engaged. The electromotive force generated by the rotary motor is radial, whereas the electromotive force generated by the feed motor is axial.

[0040] By having the drive shaft carry the magnet system and the frame carry the winding system, which is heavier than the magnet system, not only does it facilitate the wiring that supplies power to the corresponding motor, but it also limits the mass to be moved, i.e., the mass of the drive shaft, thereby improving the precision and reliability of drive shaft movement, particularly axial movement.

[0041] According to a particular embodiment, a majority of the drive shaft extends inside the frame of the machine tool.

[0042] When the speed of movement of the driving element is the same as the speed of movement of the driven element, the driving and driven elements are considered to be in direct engagement. There is no relative sliding between the elements. There may be intermediate portions, but there is no relative movement between the driving and driven parts.

[0043] Other features and advantages of the present invention are provided in the following detailed description, which is given by way of example only and is not limiting, and which should be read in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0044] [Figure 1] FIG. 1 is a schematic diagram illustrating a machine tool carried by a movable support system, such as a robot, for processing a workpiece according to one embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a machine tool with the tool in contact with a workpiece to be processed according to one embodiment of the present invention; [Figure 2A] 3 is a cross-sectional view of the machine tool of FIG. 2, in which a workpiece to be processed moves axially relative to the machine tool, resulting in axial movement of the workpiece to be processed relative to the tool. [Figure 2B]2B is an axial cross-sectional view of the machine tool of FIG. 2A, in which axial movement of the drive shaft provides axial movement of the tool to offset axial movement of the workpiece being processed relative to the tool. [Figure 3] 3 is a schematic axial cross-sectional view of a machine tool according to another embodiment; [Figure 4] 3 is a schematic axial cross-sectional view of a machine tool according to another embodiment; [Figure 5] 1 is a flowchart of a processing method using a processing system according to one embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0045] The inventive concepts will now be more fully described with reference to the accompanying drawings, which illustrate embodiments of the inventive concepts. In the drawings, the sizes and relative sizes of the elements may be exaggerated for clarity. Like numbers refer to like elements throughout the drawings. However, the inventive concepts may be embodied in many different forms and should not be construed as limited to the disclosed embodiments. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will convey the scope of the inventive concepts to those skilled in the art.

[0046] Throughout this specification, the reference to "one embodiment" means that a particular functionality, structure, or feature described in connection with an embodiment is included in at least one embodiment of the invention. Thus, the appearances of "one embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular functionality, structures, or features may be combined in any suitable manner in one or more embodiments.

[0047] Referring to the drawing, there is shown a system for processing a workpiece P1, the system including a frame 100, a machine tool M1 carried by the frame 100, a processing assembly including motorized systems 2, 3, and a drive shaft 400.

[0048] The drive shaft 400 is provided at one end with a tool holder 600 capable of receiving a tool 900 for performing processing on the workpiece P1. In the embodiment shown in Figures 2, 2A and 2B, only one end of the drive shaft 400 is provided with a tool holder, and therefore a tool. According to another embodiment, as shown in Figure 3, each end of the drive shaft 400 may be provided with a tool holder 600, and therefore a tool 900. As will be described below, the drive shaft 400 may itself be driven by systems 2 and 3, which include motors that can be controlled by a controller.

[0049] The motorized systems 2, 3 are configured not only to rotate at least the portion 4001 of the drive shaft 400 to which the tool holder 600 is fixed so as to rotate the tool 900 removably fixed to the tool holder 600, but also to move the portion 4001 of the drive shaft 400 axially (preferably by axial movement of another portion 4002 of the drive shaft, as described below) so that the tool holder 600, and therefore the tool 900 connected to the tool holder, can move axially.

[0050] Having a thrust axis (direction) corresponding to the axis of travel of the drive shaft (also called the feed axis) collinear with the axis of the tool allows for precise and reliable processing of the workpiece.

[0051] As will be described in detail below, the machine tool allows for reliable and precise real-time compensation of the axial position of the tool holder drive shaft, and therefore the tool, relative to the workpiece P1 when there is a relative axial movement of the position of the workpiece being processed relative to the machine tool frame.

[0052] The reliability of this cancellation arises from the isolation of rotation of the portion of the drive shaft to which the tool holder 600 is fixed from translation applied (directly or indirectly) to that portion of the drive shaft to which the tool holder is fixed.

[0053] According to one embodiment, as shown in the drawings, drive shaft 400 includes a first segment 4001 and a second segment 4002 that are coupled together for axial movement.

[0054] The first segment 4001, to which the tool holder 600 is fixed, can be rotated by a first motor 2, as described below. Independently of the rotation of the second segment 4002, the second segment 4002 can be moved axially by a second motor 3, as described below, and can be aligned with the first segment 4001 to move the first segment 4001 axially. The two drive shaft segments are collinear.

[0055] In other words, axial movement of the second segment, which causes axial movement of the first segment 4001, does not affect the rotation of the first segment 4001 to which the tool holder 600 is fixed. Conversely, rotation of the first segment 4001 does not affect the axial positioning of the second segment 4002. This ensures good control of process parameters by controlling the rotation and translation of the segments of the tool holder drive shaft independently of each other, while ensuring tool axis thrust that allows reliable and precise attainment of the desired final geometry of the workpiece being processed during processing operations such as drilling and countersinking.

[0056] As shown in Figure 1, the machine tool may be carried by a support system R1, such as an articulated robot, which may also be a numerically controlled machine or a specific tooling device.

[0057] The support system R1 may itself be mounted on a carrier system configured to move in several directions relative to the workpiece P1 to be processed, allowing the machine tool, and thus the tool, to be positioned in a desired position and orientation relative to the workpiece P1.

[0058] In the example shown in Figure 1, the support system R1 comprises a main base (or framework) BT1 and an arm section BRS1. The machine tool M1 is mounted to the arm section BRS1 by means of a hinge. This arm section BRS1 may comprise one or several sections joined together by means of hinges. Preferably, the arm section BRS1 is itself mounted to the base section BT1 by means of a hinge.

[0059] Advantageously, the processing system includes a device for positioning the machine M1 relative to the workpiece P1 to be manufactured, making it possible to precisely know the position and / or orientation of the machine tool relative to the workpiece P1, particularly before processing on the workpiece begins.

[0060] 1, support system R1 may be moved independently of workpiece P1, for example, support system R1 may be positioned to have a position and orientation as indicated by the short dashed line in the figure.

[0061] The tool 900 is, for example, a drilling spindle. The tool 900 has a longitudinal axis A900 that is coaxial with the axis A400 of the drive shaft 400. The tool holder 600 also has an axis A600 that is coaxial with the axis A400 of the drive shaft 400.

[0062] Systems with motors As mentioned above, the machine tool M1 includes a system with motors including a first motor 2, referred to as a rotary drive motor, configured to rotate at least a portion 4001 of the drive shaft 400.

[0063] The motorized system also includes a second motor 3, called the feed motor, which allows the drive shaft 400 to move axially, and is preferably directly engaged with the segment 4002, independent of the rotation of the segment 4001 which carries the tool 900 through the tool holder 600. In other words, the feed motor 3 allows the translation of the drive shaft along the longitudinal axis A 400 to be controlled without affecting the rotation of the shaft.

[0064] The rotary drive motor 2 is mounted to rotate integrally with the segment 4001 of the drive shaft 400 having the tool holding portion 600 for rotary drive while being in sliding connection with the segment 4001, allowing axial movement of the segment 4001 controlled by the feed motor 3.

[0065] The rotary drive motor 2 and the feed motor 3 are controllable independently of each other. As already mentioned, each motor is under the control of the controller 8 and can act on the drive shaft 400 independently of the other motor's action on the drive shaft 400, with one motor controlling only the rotation of the shaft and the other motor controlling only the axial movement. As will be described below, the two motors each act on two collinear segments of the drive shaft, making it possible to rotate the latter without generating geometric defects at the tip of the tool 900 fixed in the tool holder.

[0066] Preferably, the rotation shaft of the rotary drive motor 2 is coaxial with the shaft of the feed motor 3 .

[0067] drive shaft As already described, in the embodiment shown in Figures 1 and 2, the drive shaft 400 comprises a first segment 4001 which can be rotated by the motor 2 and to which the tool holder 600 is fixed at one end, and a second segment 4002 which can be moved axially by the feed motor 3, making it possible to push or pull the first segment 4001 axially and to move the tool 900 connected to the first segment 4001 by the tool holder axially.

[0068] The connection 4003 between the first segment 4001 and the second segment 4002 is configured so that the first segment 4001 and the second segment 4002 move axially integrally with each other while maintaining the second segment 4002 to rotate freely relative to the first segment 4001.

[0069] The connection 4003 may therefore be formed in the form of a pivot connection having a pivot axis coaxial with the axis A400 of the drive shaft 400. Optionally, the connection 4003 may be formed in the form of a ball joint.

[0070] The design of such machines allows the operation of a motor on a drive shaft to be independent of the operation of other motors on the drive shaft.

[0071] Thus, the rotation of the tool 900 and its axial position relative to the machine frame can be controlled independently of each other and therefore reliably and precisely.

[0072] The connection device 4003 between the two segments 4001 , 4002 has no axial clearance, leaving the second segment 4002 free to rotate relative to the first segment 4001 .

[0073] Such a compact structure makes it possible to apply thrust to the tool 900 in the direction of the axis of the drive shaft (spindle axis) and to separate the control of the two motors.

[0074] Such a design makes it easier to achieve control monitoring of loops such as drilling cycles, and the discontinuous cutting allows for fragmentation of shavings, thereby making it easier to remove them during operation.

[0075] In the variant shown in Figure 3 (or Figure 4), the segment 4002' mated with the tool holder engages with the feed motor 3, and the other segment 4001' engages with the rotary drive motor 2. Thus, the segment 4002', whose axial movement can be controlled by the feed motor 3, extends between the tool 900 and the segment 4001', whose rotation can be controlled by the motor 2. In this case, the connection part 4003 is a fixed connection, and the segments 4001', 4002' are integrated in axial movement and rotation.

[0076] The segment of the drive shaft 400 engaged with the feed motor 3 is different from the segment of the drive shaft 400 engaged with the rotary drive motor 2 .

[0077] According to one embodiment, two segments of the shaft of the machine tool M1 are drilled, preferably axially at their centres, to allow the passage of a coolant for the drilling operation.

[0078] Rotary motor The rotary motor 2 corresponds to a spindle motor that rotates the first segment 4001 of the drive shaft 400 that carries the tool 900. The rotary motor 2 includes a stator 200 that is fixed relative to the frame 100 of the machine M1, and a rotor 210, the rotational speed of which is controllable by the control module 810 of the control unit 8, as described below.

[0079] According to one embodiment, the first segment 4001 of the drive shaft 400 is a splined segment rotatably connected to the rotor 210 of the motor 2 by a meshing system integrated with the rotor 210 cooperating with the splined segment.

[0080] Preferably, the meshing system includes axially spaced primary and secondary meshing members 220, 230 to distribute the drive torque, increase the stiffness of the assembly, and improve the rotational precision of the first segment 4001 by providing a longer lead for the first segment.

[0081] Preferably, the stator of the rotary motor includes a winding system and the rotor includes a magnet system, and power in the winding system generates a magnetic field that interacts with the magnet system, thus generating a radial electromotive force (electromagnetic torque) that rotates at least a portion of the drive shaft engaged with the rotor.

[0082] Feed motor Preferably, the feed motor 3 is a linear motor configured to control the axial movement of the second segment 4002. Using a linear motor allows the second segment 4002 to be moved axially, and therefore the axially linked first segment 4001 does not rotate or impart a rotational movement to the second segment.

[0083] As shown in the drawing, the feed motor 3 includes a main section 300 and a secondary section 310 .

[0084] The main section 300 is fixed relative to the frame 100 of the machine M1, and the secondary section is fixed to or mounted on the drive shaft 400 and is free to translate relative to the main section 300 in a direction parallel to the axis of the drive shaft 400. According to certain embodiments, the main section 300 and secondary section 310 of the feed module may each include several main sections and several secondary sections. The feed motor generates an axial electromotive force (with an axis parallel to the axis of the drive shaft) that translates the drive shaft to which the secondary section of the feed motor is engaged.

[0085] According to one embodiment of the present invention, the main section of the feed motor includes a winding system carried and powered by the frame, and the secondary section 310 includes a magnet system. The secondary section of the feed motor includes a magnet system carried by a part integral with the drive shaft or built directly into the drive shaft. Powering the winding system generates a magnetic field that interacts with the magnet system.

[0086] Having the magnet system carried by the drive shaft and the winding system, which is heavier than the magnet system, carried by the frame not only facilitates the wiring that supplies power to the corresponding motor, but also limits the mass to be moved, i.e., the mass of the drive shaft, making it possible to improve the precision and reliability of the drive shaft's movement, especially in the axial direction. The distribution of the winding system and the magnet system could be reversed, but this would have fewer advantages.

[0087] The winding system of the feed motor may be powered to move the generated magnetic field along the axis of the drive shaft at a predetermined speed, and preferably the controller is adapted to control the speed of movement of the generated magnetic field according to a desired speed of movement, thereby enabling the axial speed of movement of the drive shaft to be controlled.

[0088] As will be described in detail below, moving the drive shaft relative to the frame of the machine tool to obtain a new reference position P4ref for the drive shaft to compensate for the movement of the workpiece being processed is achieved by controlling a single motor, the feed motor.

[0089] 1 and 2, the secondary unit 310 is mounted for translational movement together with the segment 4002 in a direction parallel to the axis of the segment 4002 (which also corresponds to the axis of the segment 4001 of the drive shaft 400). The axial movement of the secondary unit 310 is controllable by the control module 820 of the control unit 8.

[0090] Axial movement of the secondary section 310 of the motor 3 causes axial movement of the drive shaft second segment 4002. The secondary section 310 and the second segment 4002 of the motor 3 may be formed as one and the same piece.

[0091] As will be described below, the feed motor 3 moves the drive shaft 400 to allow for offsetting relative axial movement of the frame 100 of the machine M1 and the workpiece P1 (FIGS. 2, 2A, 2B).

[0092] Simply moving the drive shaft 400 axially relative to the machine frame 100 by moving the sub-portion 310 of the feed motor 3 coupled to the segment 4002 of the drive shaft 400 to offset the relative axial movement of the workpiece P1 to the machine frame 100 compared to the full movement of the machine M1 makes it possible to limit the size of the feed motor 3 and therefore the size (overall dimensions and mass) of the machine M1. Limiting the moving mass allows for an increase in the mechanical bandwidth of the system.

[0093] In other words, if a relative axial movement between the workpiece P1 and the machine frame 100 is detected during the processing operation of the workpiece P1, the tool 900 is made axially movable by moving the feed motor secondary part 310 axially relative to the feed motor main part 30, and therefore relative to the machine frame 100, thereby making it possible to axially correct the relative axial movement between the workpiece and the machine frame during the processing operation of the workpiece without moving the entire machine tool.

[0094] Naturally, when the machine tool is arranged on a moving system such as the support system R1, and is preferably itself carried by a carrying system, the entire machine can remain movable in its previous position relative to the workpiece and / or the tool 900 can be oriented as a function of the processing to be performed on the workpiece.

[0095] The motor 3 manages the feed of the second segment 4002 of the drive shaft by direct translation drive, ie the axial movement of the second segment 4002 and therefore of the tool 900 .

[0096] The direct transmission of movement between the feed motor 3 and the second segment 4002 of the drive shaft without a reduction gear such as a helical nut allows, on the one hand, high efficiency and, on the other hand, the ability to have direct and therefore noise-free force feedback information.

[0097] Such a machine design therefore allows the rotation of the tool 900 using the rotation motor 2 to be controlled independently of the axial movement of the tool, which can be controlled using the feed motor 3 .

[0098] The independence of the rotation of the first segment 4001 from the axial movement allows for control monitoring of loops such as the drilling cycle, and the discontinuous cutting allows for fragmentation of shavings, thereby making it easier to remove them during operation.

[0099] To compensate for the movement of the workpiece, the frame of the machine tool carrying the motor is kept stationary in the Earth reference frame while the drive shaft moves axially, so it is the drive shaft that moves, preferably internally along the frame of the machine tool, rather than the frame being moved in the Earth reference frame.

[0100] According to a particular embodiment, a majority of the drive shaft extends within the frame of the machine tool.

[0101] Advantageously, the sub-portion of the feed motor is in direct engagement with the drive shaft. If the speed of movement of the drive element is the same as the speed of movement of the driven element, the drive element and the driven element are considered to be in direct engagement. There is no relative sliding between the elements. There may be intermediate portions, but there is no relative movement between the drive and driven elements.

[0102] Distance Identification System The machine tool includes a distance measuring device 521 configured to measure a distance representative of the distance between the workpiece and the machine frame 100, particularly during processing of the workpiece P1 by the tool 900.

[0103] The distance measuring device 521 is connected to a control unit 8 which is configured to determine, by means of a distance change determination module 830, changes in the axial distance between the machine tool frame 100 and the workpiece to be processed P1.

[0104] As will be described below, if module 830 determines that the distance D1 between the machine tool frame 100 and the workpiece P1 to be processed has changed to a distance D1', e.g., if the difference in distances D1-D1' is greater than a threshold, then module 840 controls the axial movement of the drive shaft 400 relative to the change in the axial reference position P4ref of the shaft 400 to compensate for this change in the relative distance between the workpiece P1 and the machine tool frame 100. The axial reference position of the drive shaft is stored by the control unit 8 to enable processing instructions for the workpiece to be executed, the instructions including commands for the axial (and rotational) movement of the shaft 400, and therefore of the tool 400, as a function of the axial reference position of the drive shaft.

[0105] Control unit As already mentioned, the control unit 8 includes a rotation control module 810 that allows for control of the rotation speed of the rotary drive motor 2. Preferably, the rotation control module 810 is configured to allow for a constant rotation speed of the motor 2, and therefore the tool to be held, while allowing for the tool speed to be varied as required.

[0106] The control unit 8 also includes a feed control module 820 that controls the feed motor 3 to enable control of the axial movement of the second segment 4002 and therefore the first segment 4001 coupled to the tool holder 600.

[0107] The machine tool includes a sensor for the position of the segment 4002 engaged with the feed motor 3. Such a position sensor is connected to the control 8, allowing the control to know precisely the position of the segment and to vary the amplitude of the feed movement waveform in real time.

[0108] Advantageously, the feed control module 820 is configured to enable the axial movement of the second segment 4002 to be controlled at a constant speed.

[0109] Preferably, the feed control module 820 is also configured to control the axial movement of the second segment 4002 with vibration superimposed thereon.

[0110] The control unit controls the rotary drive motor 2 and the feed motor 3 simultaneously and independently.

[0111] The control unit 8 includes a control module 840 configured to control the feed motor 3 in accordance with the change in distance between the frame 100 of the machine tool M1 and the workpiece P1 to be processed determined by the module 830 to move the drive shaft axially a distance equal to the determined change in distance. The drive shaft then has a new axial reference position P4ref at which the processing command for the workpiece P1 can be continued, which position allows the relative axial movement of the workpiece P1 with respect to the frame of the machine tool M1 to be compensated for.

[0112] Thus, if there is a relative axial movement of a predetermined value between the frame 100 of the machine tool M1 and the workpiece P1 to be manufactured, the machine allows the axial position of the shaft 400, and therefore the tool 900, to be offset in real time by the same value.

[0113] The machine tool may include an interface that allows selection of one or several vibration parameters (frequency and / or amplitude) and / or signal shape (sine, triangular, trapezoidal, etc.).

[0114] These parameters may be selected according to predetermined criteria, such as material hardness, and may be further modified in real time to enhance swarf fragmentation. Furthermore, the vibration parameters may be automatically defined or modified according to the results of a process test phase for the material being processed.

[0115] According to one embodiment, the control unit 8 is configured to vary the settings for each control module 810, 820 in real time as a function of data relating to the current consumed by the feed motor 3 and data provided by the system for identifying variations in the distance between the machine M1 and the workpiece P1.

[0116] According to one embodiment, the variation between the machine tool M1 and the workpiece P1 to be produced can be measured using a distance sensor 521 configured to measure the distance between a pressing device, referred to as the blank holder tip, and the workpiece P1 to be produced, the pressing device including a part 520 mounted beyond the machine tip on a part of the machine, i.e. at the end of the machine where the tool is located, intended to press against the workpiece P1 to be processed, and a part 510 of the machine frame, relative to which part 520 is movable in a direction parallel to the axis of the drive shaft. Furthermore, a value of the variation in distance can be provided by the distance measurement sensor 521 mounted on part 510.

[0117] Part 520 has a through hole for the passage of a processing tool. Part 520 is mounted for axial movement relative to the frame, for example by a return spring, so that it can compress the workpiece to be processed, and relative axial movement between the workpiece to be processed and the machine frame in the direction away from workpiece P1 causes axial spacing of part 520 of the blank holder system relative to part 510 connected to the machine frame.

[0118] Alternatively, the blank holder system may be mounted on a support external to the machine tool and fixed relative to the machine tool, and uses at least one distance sensor to maintain the fixed portion 510 and the movable portion 520 in contact with the workpiece P1 to be manufactured, and to measure the relative axial movement between the two portions 520, 510.

[0119] Preferably, the processing system includes a device for measuring the orthogonality of the tool of the machine M1 (or the axis of the drive shaft 400) with the workpiece P1.

[0120] In FIG. 2, the tip of the blank holder first presses the workpiece P1 so that the distance between the portion 520 of the tip of the blank holder and the portion 510 fixed to the frame 100 is equal to D1.

[0121] 2A shows the case where, during processing of workpiece P1, workpiece P1 moves backward relative to the machine frame, and movable portion 520 at the tip of the blank holder that presses against the workpiece presses the workpiece backward and then moves a distance D1' away from frame 100. In particular, FIGS. 2, 2A, and also 2B show the relative movement between machine tool M1 and workpiece P1 being processed, and the associated compensation in the machine axes to keep tool 900 held in the same position relative to workpiece P1 in real time.

[0122] Therefore, the distance change determining system determines that the workpiece P1 has moved axially a distance D1-D1'.

[0123] The compensation module 840 of the control unit 8 controls the axial movement of the drive shaft, here feeding it by a distance equal to D1-D1' to compensate for the backward movement of the workpiece relative to the frame, so that, for example, the reference position P4ref (original position) of the shaft 400 defined as the position of the free end of the segment 4002 relative to the frame 100 is changed to the position P4ref' with the distance between the reference positions P4ref' and P4ref equal to the distance D1-D1'.

[0124] Thus, as shown in FIG. 2B, the position of the drive shaft 400 (machine axis) relative to the workpiece P1 is offset for the value of the relative axial movement between the workpiece P1 and the machine frame, i.e., the value D1′-D1, and the position of the drive shaft is fed a distance D1-D1′ relative to the frame (in the direction of the workpiece P1).

[0125] According to one embodiment, the control module 830 is configured to analyze data from the two control modules 810, 820 in real time to estimate the relative position between the tool 900 and the workpiece P1 before the tool is inside this workpiece.

[0126] Furthermore, the module 830 of the control unit 8 is configured to analyze in real time the data from the two control modules 810, 820 in order to estimate the relative position of the cutting tool 900 relative to the changes in the material of the workpiece P1 to be processed and to adapt in real time the cutting parameters of the material to be processed according to the adopted strategy.

[0127] Additionally, the control module 830 analyzes data from the two control modules 810, 820 in real time to determine the wear rate of the tool 900.

[0128] method The system described so far makes it possible to carry out a workpiece processing method using a machine tool M1 having a tool holder 600 equipped with the above-described tool 900. Next, an example of the method will be described with reference to FIG.

[0129] The method includes the following steps: In step 1010, the machine tool M1 is positioned relative to the workpiece P1 so that the workpiece P1 can be processed with the tool 900 (by rotation and / or axial movement of the tool 900 relative to the workpiece P1).

[0130] The distance between the workpiece P1 and the frame 100 of the machine tool M1 is equal to a value D1, referred to as the initial value. The drive shaft 400 has an axial reference position P4ref relative to the frame 100 of the machine tool. In Figure 2, the axial reference position is represented as the position of the end of the drive shaft 400 opposite the tool, but this axial reference position may be represented relative to other portions of the drive shaft 400.

[0131] The control unit 8 stores this axial reference position P4ref.

[0132] In step 1020, a processing operation on the workpiece P1 is performed by controlling the rotary drive motor 2 to rotate the tool 900 and / or by controlling the feed motor 3 to move the tool 900 axially relative to the workpiece P1.

[0133] For processing of the workpiece to be processed, the axial movement of the tool 900 is controlled as a function of the axial reference position P4ref of the drive shaft.

[0134] In step 1030, during processing of workpiece P1, the controller determines whether the distance between workpiece P1 and the machine frame has changed.

[0135] If there is no change, the processing operation on workpiece P1 continues to be performed without further intervention on the drive shaft (step 1020).

[0136] If there is a change, that is, if it is determined that the distance D' between the workpiece P1 and the machine frame 100 has changed, the distance D1 between the workpiece P1 and the frame 100 of the machine tool M1 becomes equal to the new value D1'.

[0137] Next, in step 1040, the control module 840 controls the movement of the workpiece P1, the axial movement of the drive shaft of the tool holder 600 relative to the frame of the machine tool, to be offset by a distance corresponding to the difference between the new value D1' and the initial value D1, referred to as the offset distance. The axial reference position of the drive shaft 400 is then changed to the new axial reference position P4ref' stored by the control module 8. This new axial reference position P4ref' corresponds to the previous axial reference position P4ref plus the offset distance.

[0138] In step 1050, the processing operations on the workpiece P1 continue and are performed as a function of the new reference position P4ref' of the shaft.

[0139] The ability to control the axial movement of the drive shaft during operation of the machine tool allows for correction of the tool position, thereby maintaining the relative position of the tool relative to the workpiece being processed, even when there is relative axial movement between the workpiece being processed and the machine tool.

[0140] The control unit 8 may for example be in the form of a processing unit and a data memory in which computer instructions executable by the processing unit are stored, and may also be in the form of a microcontroller.

[0141] In other words, the described functions and steps can be implemented in the form of a computer program or via hardware elements (e.g., a programmable gate network). In particular, the functions and steps performed by the controller, in particular controlling the motors, can be performed by a set of instructions or computer modules executed by the processor or controller, or by dedicated electronic elements or components of the Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (or ASIC) type. It is also possible to combine computer and electronic components.

[0142] Thus, the control unit is an electronic and / or computer unit. When this unit is specified as being configured to perform a certain operation, it means that the unit includes computer instructions and corresponding execution means that enable the operation to be performed and / or that the unit includes corresponding electronic elements.

[0143] The machine tool therefore makes it possible to identify possible relative axial movements between the frame 100 of the machine tool M1 and the workpiece P1 to be manufactured, and to compensate for this relative axial movement in real time during processing operations on the workpiece.

[0144] Having the two motors separated, in particular the rotation of the first segment controlled by the rotation motor 2 being independent of the axial movement of the second segment controllable by the second motor 3, makes it possible to avoid generating geometric defects at the tip of the tool 900 during rotation.

[0145] Indeed, separating the motors from each other allows the orientation of the interconnection plane between the tool holder 600 and the segment of the shaft 4000 carrying the tool holder to be maintained, this interconnection plane being a reference plane perpendicular to the machine axis that prevents the generation of geometric defects at the tip of the tool 900 during rotation.

[0146] This compensation allows precise processing of the workpiece, especially for countersinking operations, since countersinks generally must be positioned very precisely relative to the surface of the workpiece P1.

[0147] Advantageously, the system may include optical devices that make it possible to measure the quality of the processing carried out on the workpiece P1.

[0148] Usage example The machine tool can be a machine adapted to perform different operations such as milling, trimming, drilling, threading, and nut driving operations, etc. The tools coupled to the machine are then adapted to perform such operations.

[0149] As previously mentioned, the machine tool may be embedded in a numerically controlled machine, robot, or tooling system.

[0150] According to one embodiment, the machine tool includes a system for measuring the current consumed by the feed motor, and the control is configured to accommodate processes such as selecting automatic changes in cutting parameters when drilling an assembly of multiple materials, taking into account the type of material being drilled and the second material being drilled.

[0151] According to one embodiment, the machine tool includes a blank holder tip coupling interconnection, preferably automatically configured to change the blank holder tip depending on the workpiece being processed. This interconnection includes centering and flat pressure to ensure repeatable positioning. Preferably, this interconnection also includes, for example, pneumatic and electrical connections for the blank holder function and for measuring the distance and orthogonality of the machine M1 relative to the workpiece P1 being processed.

[0152] The tip can be a blank retainer tip (or blank retainer) as shown in FIG. 2, a concentric collar type tip, or a quarter turn type tip.

[0153] The blank holder tip can be used in automated applications involving machine tool placement means such as a robot or numerically controlled machine. The machine tool M1 can also be used in portable applications. Of course, the machine can also be used without the tip in certain applications.

[0154] According to a particular embodiment, when using a tip, an inner guidance part of the tool holder is provided inside the tip, in particular to limit the possibility of vibration modes.

[0155] Thus, according to one embodiment, the tip includes an inner element that guides the tool holder and a blocking element 530, called a blocker, that blocks rotation of the tool holder and allows the tool holder to be screwed or unscrewed onto the first segment 4001 of the shaft.

[0156] The tool holder is secured to the first segment of the drive shaft by screwing the tool holder onto the first segment of the drive shaft. A blocker is used to mount or dismount the tool holder relative to the drive shaft, and the tool holder can be screwed onto or unscrewed from the drive shaft by blocking the tool holder on the blocker through cooperation of male and female features.

[0157] According to one embodiment, the machine includes electrical connections 710 and pneumatic connections 720 to allow the machine tip to be automatically connected and disconnected from the machine.

[0158] The present invention is not limited to the embodiments shown in the drawings, and therefore, where reference signs are used following features in the appended claims, it should be understood that these signs are used merely to facilitate reading of the claims and are in no way intended to limit the scope of the claims.

[0159] Furthermore, the term "comprising" does not exclude other elements or steps. Furthermore, features or steps described with respect to one disclosed embodiment may be used in combination with other features or steps in other disclosed embodiments. [Explanation of symbols]

[0160] 2 First Motor 3 Second Motor 8 Control Unit 100 frames 400 drive shaft 521 Distance measuring device 600 Tool holder M1 Machine Tool

Claims

1. In a system for processing a workpiece (P1) including a machine tool (M1), The machine tool (M1) A frame (100); a drive shaft (400) having a longitudinal axis (A400), the drive shaft (400) being provided with a tool holder (600) to which a tool (900), such as a drilling spindle, can be coupled; a first motor (2), referred to as a rotary drive motor, configured to rotate at least a portion of the drive shaft (400) coupled to the tool holder (600); a second motor (3), called a feed motor, configured to move the drive shaft (400) axially relative to the frame (100) of the machine tool (M1), the second motor (3) being preferably a linear motor; and The system further comprises: a distance measuring device (521) configured to measure a distance representative of the distance between the workpiece (P1) and the frame (100) of the machine tool (M1); A control unit (8) Including, The control unit (8) A processing operation on the workpiece (P1) is performed by controlling the rotation drive motor (2) to rotate the tool holding unit (600) and / or by controlling the feed motor (3) to move the tool holding unit (600) in an axial direction; Using the distance measuring device (521), a change in the axial distance (D1'-D1) between the frame (100) of the machine tool (M1) and the workpiece (P1) caused by a relative axial movement between the workpiece (P1) to be processed and the frame (100) of the machine tool (M1) is determined; and controlling the second motor (3) to move a drive shaft (400) axially relative to the frame (100) of the machine tool (M1) in response to the change in the specified distance between the frame (100) of the machine tool (M1) and the workpiece (P1) to be processed, thereby offsetting the relative axial movement between the workpiece (P1) and the frame (100) of the machine tool (M1); The system is further characterized in that the rotary drive motor (2) and the feed motor (3) are configured to control the axial movement of the at least a portion of the drive shaft (400) coupled to the tool holding portion (600) independently of the rotation of the at least a portion of the drive shaft (400) coupled to the tool holding portion (600).

2. 2. The system of claim 1, wherein the feed motor (3) is a linear motor having a main section (300) fixedly mounted relative to the frame (100) of the machine tool (1) and a secondary section (310) mounted for movement relative to the main section in a direction parallel to the longitudinal axis of the drive shaft (400), the secondary section being fixed to a segment (4002) of the drive shaft (400) or being formed integrally with the segment (4002) of the drive shaft (400).

3. 3. The system of claim 2, wherein the secondary section (310) includes a magnet system and the main section (300) of the feed motor (3) includes a powered winding system that, when powered, generates a magnetic field that interacts with the magnet system to generate an electromotive force on an axis parallel to the longitudinal axis of the drive shaft.

4. 4. The system according to claim 1, wherein the distance measuring device (521) is carried by a movable part (520) of a pressing device, referred to as a blank holding part tip (520), the movable part (520) of the blank holding part tip being mounted so as to be movable relative to a part (510) fixed relative to the frame (100), the movable part (520) being configured to press the workpiece (P1) backward, and the distance measuring device (521) is arranged to measure the distance between the movable part (520) of the blank holding part tip and the fixed part (510).

5. 5. The system of claim 1, wherein the drive shaft (400) includes a first segment (4001) and a second segment (4002) connected to each other by a connecting device (4003), one of the segments engaging with the feed motor (3) and the other segment engaging with the rotary drive motor (2).

6. 6. The system of claim 1, wherein the drive shaft (400) includes a first segment (4001) and a second segment (4002) connected to each other by a connecting device (4003), the connecting device (4003) being configured to move the first segment (4001) and the second segment (4002) together in an axial direction while maintaining the first segment (4001) free to rotate relative to the second segment (4002).

7. 7. The system of claim 5 or claim 6, wherein the first segment (4001) to which the tool holder (600) is fixed is rotatable by the rotary drive motor (2), and the second segment (4002) is axially movable by the feed motor (3).

8. 8. The system according to claim 1, further comprising a support system (R1), such as an articulated robot, carrying a machine tool (M1), the machine tool (M1) being hingedly mounted to the support system (R1) for positioning the machine tool (M1) in a desired position and orientation relative to the workpiece to be processed.

9. 9. A system according to any one of claims 1 to 8, wherein the support system (R1) comprises a main base (BT1) and an arm section (BRS1), the machine tool (M1) being mounted to the arm section (BRS1) by means of a hinge, the arm section (BRS1) comprising one or several sections joined together by means of hinges, preferably the arm section (BRS1) being mounted to the main base (BT1) by means of a hinge.

10. The system of any one of claims 1 to 9, wherein the control unit (8) is configured so that the drive shaft (400) is freely movable in order to move the tool (900) axially at a variable speed to fragment shavings resulting from the tool (900) processing the workpiece (P1) to be processed.

11. A workpiece processing method using the processing system according to any one of claims 1 to 10, The machine tool (M1) of the processing system includes the tool holder (600) with the processing tool (900), and the method comprises: a step (1010) of positioning the machine tool (M1) relative to the workpiece (P1) in terms of processing the workpiece (P1) using the processing tool (900), such that the distance (D1) between the workpiece (P1) and the frame (100) of the machine tool (M1) is equal to a value (D1) called the initial value, and the drive shaft (400) has an axial reference position (P4ref) relative to the frame (100) of the machine tool; a step (1020) of performing a processing operation on a workpiece (P1) by controlling the rotary drive motor (2) to rotate the processing tool (900) and / or by controlling the feed motor (3) to move the processing tool (900) axially, the axial movement of the processing tool (900) being controlled as a function of the axial reference position (P4ref) of the drive shaft; a step (1030) of determining, during processing of the workpiece (P1), a change in the distance (D1') between the workpiece (P1) and the frame (100) of the machine tool, so that the distance (D1) between the workpiece (P1) and the frame (M1) of the machine tool (M1) is equal to the new value (D1'); a step (1040) of offsetting the movement of the workpiece (P1) due to the axial movement of the drive shaft (400) of the tool holder (600) by a distance, called an offset distance, corresponding to the difference between the new value (D1') and the initial value (D1), to define a new axial reference position (P4ref') of the drive shaft; a step (1050) of continuing the processing operation on the workpiece (P1) as a function of the new reference position (P4ref') of the shaft; A workpiece processing method comprising:

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