Numerically-controlled machine tool comprising multi-spindle turret and tool clamping device

Abstract

The utility model relates to a numerical control machine tool comprising a multi-spindle turret and a tool clamping device. The utility model relates to a numerical control machine tool which comprises a multi-spindle turret, the turret is provided with a main body extending along an axis A-A between a first end and a second end, the main body is fastened to a frame of the machine tool through the first end, and the main body comprises a rotatable head at the second end. The head comprises at least two tool-holding spindles each intended to receive a cutting tool in an engaged manner, the spindles occupying, depending on the head angular position, a working position in which they are intended to perform a machining operation on the workpiece held in position in the fixture, or a standby position in which they are withdrawn from the workpiece, each spindle is configured to be controlled independently of the other spindles to fixedly or rotatably drive its carried tools regardless of its occupied position, the machine tool further comprising a tool holding device configured to take out the tools carried by the spindles in a standby position for its storage and to insert replacement tools into the spindles.

Description

Field of the Invention

[0001] The present invention relates to the field of numerical control machines for machining workpieces, preferably micromachined workpieces, and to the field of equipment for such machines.

[0002] More particularly, the present invention relates to a numerical control machine including a multi-spindle turret and a tool holding device. Background Art

[0003] Numerical control machines are designed to produce mass-produced parts following the instructions of a computer program, particularly by machining. These machines include tools held in tool holding spindles, and are generally equipped with a tool changing device to change the tool held by the tool holding spindle so as to adapt it to the machining operation to be performed on a workpiece held in place in a fixture.

[0004] During tool change, the machine tool is no longer producing, which means that the machining operation is interrupted. Thus, the aim is to minimize the time required to change the tool. To this end, tool changing devices have been developed to work as much as possible simultaneously with the machining operation and to minimize the machine tool downtime in order to increase its productivity.

[0005] For example, it is known that a multi-spindle turret includes a head on which a plurality of tool holding spindles are arranged, one of which is in operation and the others are stationary. In particular, the operating tool holding spindle engages with a drive mechanism by means of a coupling system. Thus, between two machining operations, the tool can be changed by uncoupling the operating tool holding spindle, i.e., the spindle carrying the tool to be changed, rotating the head so as to present the next tool holding spindle, and coupling this tool holding spindle to the drive mechanism.

[0006] However, this solution is not entirely satisfactory because, although the tool change time is reduced, it is not performed entirely simultaneously with the machining operation. More particularly, between each tool change, for this type of multi-spindle turret, it is necessary to brake the tool to be changed before performing the tool change and to accelerate the next tool once it is coupled to the drive mechanism until it reaches its rotational machining speed. These multi-spindle turrets also require a certain amount of time to uncouple the tool to be changed, pivot the head and index the next tool so as to align it with the coupling system, and then perform the coupling. Due to this coupling system, this solution is also particularly complex and expensive.

[0007] The multi-spindle turret solves the problem of accelerating and braking the tool-holding spindles, where the tools are all rotatably and synchronously driven. Thus, when changing a tool, the next tool is already driven at its rotational machining speed and can start machining the workpiece. However, these multi-spindle turrets require a large amount of energy to rotate all the tools simultaneously. Moreover, due to the motion transmission kinematic chain, the maximum rotational speed of the tools they carry is relatively limited.

[0008] Overall, whether they rotate the tools they carry individually or simultaneously, the multi-spindle turrets of the prior art are bulky, which generates a large moment of inertia and increases the risk of collision between the fixture and the tools carried by the turret.

[0009] In addition to the disadvantages mentioned above, it is to be understood that these solutions are also not suitable for machining micromechanical workpieces. Summary of the Utility Model

[0010] The present utility model overcomes the foregoing disadvantages by providing a solution that allows the tools to be completely replaced and substituted simultaneously with the machining operation, in particular by performing the tool acceleration and deceleration phases simultaneously with the machining operation, and by engaging the multi-spindle turret with the tool clamping device simultaneously with the machining operation.

[0011] To this end, the present utility model relates to a numerically controlled machine tool that includes a multi-spindle turret having a body extending along axis A-A between a first end and a second end. Through the first end, the body is fastened to the frame of the machine tool. At the second end, the body includes a rotatable head. The head includes at least two tool-holding spindles, each of which is adapted to receive a cutting tool in an engaging manner. Depending on the angular position of the head, the spindles occupy a working position or a standby position. In the working position, they are adapted to perform a machining operation on a workpiece held in place in a fixture. In the standby position, they are withdrawn from the workpiece. Each spindle is configured to be controlled independently of the other spindles so as to fixedly or rotatably drive the tool it carries, regardless of the position occupied by the spindle. The machine tool also includes a tool clamping device configured to interact with the spindles in the standby position so as to remove the tools carried by the spindles for storage and to insert replacement tools into the spindles.

[0012] Since the spindles are controlled independently, they can be accelerated and decelerated simultaneously with the machining operation. Thus, the present utility model allows the non-productive time for changing tools to be reduced to only the duration of the head rotation until the next tool contacts the workpiece, while enabling the replacement of tools on the spindles in the standby position simultaneously with the machining operation.

[0013] In a particular embodiment, the present utility model may also include one or more of the following features, which must be considered individually or in any technically possible combination.

[0014] In a particular embodiment, the gripping device comprises a toolholder which is held in a cantilever position by a support structure fastened to the body of the turret. The toolholder comprises a storage magazine having a degree of rotational freedom about axis C-C.

[0015] In a particular embodiment, the toolholder is configured such that axis C-C is parallel to the longitudinal axis B'-B' or B”-B” of the main spindle with which it interacts, and the storage magazine and the main spindle are translatable relative to each other along axis C-C.

[0016] In a particular embodiment, the toolholder has at least one degree of translational or rotational freedom, thereby allowing it to move between the following positions:

[0017] - an active position, in which the toolholder is adjacent to the main spindle which it is configured to interact with, and

[0018] - a disengaged position, in which the toolholder is further away from axis A-A than when it is in the active position.

[0019] In a particular embodiment, the support structure comprises a connecting member which is fastened to the body of the turret and is connected to the toolholder by an arm which is configured to move the toolholder between its active and disengaged positions.

[0020] In a particular embodiment, the arm has a distal portion fastened to the toolholder, and the distal portion is connected to a proximal portion fastened to the connecting member by a slide or a pivot.

[0021] In a particular embodiment, the machine tool comprises at least two main spindles occupying standby positions, and the connecting member is fastened to the body of the turret so as to be rotatable about axis A-A in order to drive the toolholder from one main spindle occupying a standby position to another.

[0022] In a particular embodiment, the toolholder has a certain degree of translational mobility relative to the connecting member along an axis parallel to axis A-A so as to move the toolholder further away from the turret head when the toolholder occupies the disengaged position.

[0023] In a particular embodiment, the connecting member is fastened to the body of the turret such that it can slide along axis A-A so as to move the toolholder further away from the head of the turret when the toolholder occupies the disengaged position.

[0024] In a particular embodiment, the tool holder includes a protective housing provided with a notch, the notch including an axial portion and a radial portion, thereby allowing both the spindle and the tool to be stored to be inserted into the tool holder and allowing the tool holder to be disengaged when the tool has been replaced.

[0025] In a particular embodiment, the radial portion of the notch is shaped to match the shape of the spindle when the tool is replaced. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] With reference to the accompanying drawings, other features and advantages of the present invention will become apparent from the following detailed description given by way of example and not by way of limitation, in which:

[0027] - Figure 1 A perspective view of a multi-spindle turret according to a preferred exemplary embodiment of the present invention is shown, in which a tool holding device is capable of replacing a tool carried by one or more main spindles of the turret;

[0028] - Figure 2 A view of the turret shown in Figure 1 oriented along the longitudinal axis of the body of the turret;

[0029] - Figure 3 A perspective view of the turret in Figure 1 including a smaller tool holding device is shown, the drawing revealing a certain degree of possible mobility of the tool holding device.

[0030] It should be noted that, for clarity, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION

[0031] The present invention relates to a numerically controlled machine tool 10, as Figure 1 shown in

[0032] including a multi-spindle turret 20 for machining preferably micro-mechanical workpieces and a tool holding device 30.

[0033] The head 23 includes at least two tool - holding spindles 24, 24' or 24”, each of which is intended to engage a tool 25, 25' or 25”. Depending on the angular position of the head 23, each spindle 24, 24' and 24” occupies a working position in which the spindle is intended to perform a machining operation on a workpiece held in place in a fixture, or a standby position in which the spindle is withdrawn from the workpiece. In Figures 1 to 3 the turret 20 includes three spindles 24, 24' and 24”, one of which is in the working position and two of which are in the standby position. It is to be understood here that rotation of the head 23 causes tool change, the tool 25 occupying the working position is moved to the standby position, and one of the tools 25' or 25” in the standby position is moved to the working position.

[0034] It should be noted that the turret 20 can be driven translatably. For example, in the case where the base 22 is fastened to a carriage (not shown in the figure) of the machine tool 10, the carriage can move relative to the XYZ trihedron with at least one translational degree of freedom, preferably with three translational degrees of freedom.

[0035] Alternatively, the turret 20 can be stationary, for example, in the case where the base 22 is directly fastened to the frame 11 of the machine tool 10. Thus, the fixture is provided with the aforementioned degrees of freedom, for example, three translational degrees of freedom respectively along the directions X, Y and Z, and optionally one or two rotational degrees of freedom about X and / or Y.

[0036] The spindles 24, 24' and 24” are advantageously configured such that they can be controlled independently of each other to rotate or hold stationary the tools 25, 25' or 25” carried by them. This feature is particularly advantageous when changing tools. Preferably, the spindles 24, 24' and 24” are motor spindles, also known as “electric spindles”, and each includes its own motor for rotating or holding stationary the tools 25, 25' or 25” carried by it.

[0037] In particular, in order to replace a first tool 25 performing a first machining stage with a second tool 25' or 25” intended to perform a second machining stage, before the end of the first machining stage, the latter is driven rotatably until it reaches the rotational speed specific to the second machining stage.

[0038] The first tool 25 is engaged in the spindle 24 in the working position, and the second tool 25' or 25” is engaged in one of the spindles 24' or 24” in the standby position.

[0039] Once the first machining stage is completed, the head 23 is pivoted so as to drive the spindle 24 in the working position to the standby position and the spindle 24' or 24'' in the standby position to the working position. Then, due to the fact that the second tool 25' or 25'' reaches its rotational machining speed when the spindle 24' or 24'' with which it engages is in the standby position, the second machining stage immediately begins. With the spindle 24 carrying the first tool 25 now in the standby position, its rotational movement stops.

[0040] Thus, when the second tool 25' or 25'' rotates and the first tool 25 stops rotating simultaneously with the machining operation, the non-productive time for tool change is reduced only to the duration of the rotation of the head 23 along the axis A - A.

[0041] Each of the spindles 24, 24' and 24'' extends along a longitudinal axis, which are referred to as the "axis B - B", "axis B' - B'" and "axis B'' - B''", and the above axes also constitute their rotational axes, as Figure 1 shown. As can be seen in Figure 1 and Figure 3 In the working position, the spindle 24 is preferably oriented such that its axis B - B is parallel to the vertical axis.

[0042] Advantageously, the present utility model enables the tool 25' or 25'' to be stored to be replaced during the execution of the machining operation, which is carried by one of the spindles 24' or 24'' in the standby position and not rotating. More specifically, the machine tool 10 includes a tool clamping device 30, which is capable of removing the tool 25' or 25'' to be stored from the spindle 24' or 24'', and inserting a new tool, referred to as the "replacement tool" 25''', into the spindle 24' or 24'', as described below.

[0043] The clamping device 30 is fastened to the body 21 of the turret 20, as Figures 1 to 3 shown, for example, in the case where the base 22 is fastened to a carriage movable relative to the frame 11.

[0044] As can be seen from Figures 1 to 3 The clamping device 30 includes a tool magazine 34 held in a cantilever manner by a support structure 31. The tool magazine 34 includes a tool storage barrel 340, which includes a plurality of recesses 341, and these recesses 341 are intended to receive the replacement tool 25''' or the tool to be replaced. In particular, each of the recesses 341 may include a radially open opening through which they can releasably receive the replacement tool 25''' or the tool to be replaced.

[0045] In this example, the storage barrel 340 may be in the form of a disk having recesses 341 uniformly distributed around its periphery.

[0046] Each recess 341 may include a clamping member formed by a clamp 342, as illustrated in the detailed view in Figure 2 . Each clamp 342 has elastic deformation characteristics such that it can engage and receive a cutting tool and hold it in place in the recess 341 by friction. In particular, the cutting tool may include an annular groove 250 in which the clamp 342 is designed to engage. It should be noted that such elastic clamps are known to those skilled in the art and their design is within their capabilities.

[0047] In Figures 1 to 3 the exemplary embodiment of the present utility model shown, the storage barrel 340 has a rotational degree of freedom about an axis C-C, which is parallel to the axis B'-B' or axis B”-B” of one of the spindles 24' or 24” in the standby position, and in particular the spindle 24' with which it interacts, so as to be able to orient each recess 341 included therein towards the spindle 24'. This degree of freedom is indicated by the arrow 40 in Figure 3 .

[0048] The storage barrel 340 and the spindle 24' with which it interacts may also be translatable relative to each other along an axis parallel to the axis B'-B' of the spindle 24'. This relative mobility is preferably ensured by the translational degree of freedom of the storage barrel 340 along the axis C-C, as indicated by the arrow 41 in Figure 3 . Alternatively, this relative mobility may be ensured by the translational degree of freedom of the spindle 24' in the standby position along the axis B'-B'.

[0049] More specifically, in order to replace the cutting tool 25' engaged in the spindle 24' in the standby position with a replacement cutting tool 25”' provided in the storage barrel 340, the latter is pivoted so that the empty recess 341 faces the cutting tool 25' to be stored, and then the storage barrel 340 is translatably moved towards the spindle 24' so as to insert the cutting tool 25' to be stored into the recess 341. During the insertion of the cutting tool 25' to be stored into the recess 341, its clamp 342 deforms until it engages in the annular groove 250 of the cutting tool 25' to be stored. Then, the translation of the storage barrel 340 in a direction opposite to that of the spindle 24' allows the cutting tool 25' to be removed for storage. In order to insert the replacement cutting tool 25”' into the spindle 24', the storage barrel 340 is pivoted until the replacement cutting tool 25”' is aligned with the spindle 24', and then it is translated towards the spindle 24' so as to engage the replacement cutting tool 25”' in the spindle 24'. The translational movement in a direction perpendicular to the axis B'-B' allows the replacement cutting tool 25”' to be removed from the recess 341 in which it is located, and the replacement cutting tool 25”' is now fastened in the spindle 24'.

[0050] It should be noted that if the recess 341 is arranged such that its opening is tangentially or orthoradially open with respect to the storage barrel 340, by rotating the storage barrel 340 about the axis C-C in two opposite directions accordingly, the tool 25' to be stored is engaged in the recess 341 and the replacement tool 25''' is removed from the recess 341.

[0051] In a manner known per se to those skilled in the art, during these operations, the spindle 24' is controlled such that when the storage barrel 340 is translatably moved in a direction opposite to that of the spindle 24', the tool 25' to be stored is released, and is configured to lock the replacement tool 25''' when the replacement tool 25''' is inserted therein.

[0052] Advantageously, the tool holder 34 may have one or more translational or rotational degrees of freedom, thereby allowing it to move between an operating position and a disengaged position. In this operating position, the tool holder 34 is adjacent to the spindle 24' or 24'' in the standby position, in particular the spindle 24', and the tool holder 34 is intended to interact with this spindle 24' in order to remove the tool 25' to be stored, which it carries, or to insert the replacement tool 25''' into the said spindle 24', as described above. In this disengaged position, the tool holder 34 is further away from the axis A-A and thus further away from the head 23 than when it is in the operating position. Such an arrangement prevents any risk of the tool holder 34 colliding during the machining operation or when the head 23 rotates to change the tool.

[0053] To this end, the support structure 31 is configured to move the tool holder 34 between its operating position and its disengaged position.

[0054] In particular, as Figures 1 to 3 shown, the support structure 31 may include a coupling member 32, which is fastened to the body 21 of the turret 20 and is connected to the tool holder 34 by an arm 33. The arm 33 is configured to move the tool holder 34 between its operating position and its disengaged position. In particular, the arm 33 may be configured to translatably move the tool holder 34 along an axis that is substantially orthogonal to the axis B'-B' of the spindle 24' in the standby position, with which the tool holder 34 interacts, as Figure 3 shown by the arrow 42 in

[0055] In this exemplary embodiment, the degree of translatability of the tool holder 34 along an axis that is substantially orthogonal to the axis B'-B' of the spindle 24' is provided by the distal portion 330 of the arm 33, which is fastened to the tool holder 34 and is connected by a slider to the proximal portion 331 fastened to the coupling member 32.

[0056] Alternatively, in an exemplary embodiment not shown in the drawings, in order to move it between one and the other of its operating position and disengaged position, the tool holder 34 can pivot relative to the arm 33 about a rotation axis parallel to the axis B'-B' of the main spindle 24' intended to interact with it, and the distal part 330 is thus pivotally connected to the proximal part 331. It is to be understood here that the tool holder rotates in such a way that the storage barrel 340 is eccentrically driven so as to move it away from or towards the main spindle 24' intended to interact with it.

[0057] Preferably, the coupling member 32 is formed by a fastening ring arranged around and fastened to the body 21 so as to be rotatable about the axis A-A, as Figure 3 shown by the arrow 44 in. The shape of this fastening ring allows the forces involved to be advantageously distributed. This mobility makes it possible to move the tool holder 34 so as to successively interact with all the main spindles 24' and 24'' occupying the standby positions, and thus to be able to replace the tools 25' and 25'' of these main spindles without rotating the head 23 of the turret 20.

[0058] Advantageously, by means of the arm 33, the tool holder 34 can have a certain degree of translational mobility relative to the coupling member 32 along an axis parallel to the axis A-A so as to move the tool holder 34 further away from the head 23 when the tool holder 34 is in the disengaged position. In particular, as Figure 3 illustrated by the arrow 43 in, the proximal part 331 of the arm 33 can be fastened to the coupling member 32 so as to be translatable along an axis parallel to the axis A-A.

[0059] Alternatively, the coupling member 32 can be fastened to the body 21 of the turret 20 such that it can slide along the axis A-A.

[0060] In an exemplary embodiment of the present invention in which the turret is immobile relative to the frame 11, the fixing device has a degree of translational and rotational mobility suitable for performing machining programs.

[0061] Advantageously, as can be seen in Figures 1 to 3 the tool holder 34 includes a protective housing 35 which, in these drawings, is shown in the form of a rigid wall having an axisymmetric shape. Due to the kinematics described above, the protective housing 35 includes a notch 350 through which the tools 25', 25'' or 25''' can pass when the tool holder 34 moves.

[0062] In particular, the notch 350 includes an axial portion and a radial portion, thereby allowing both the spindle 24' and the tool 25' to be stored to be inserted into the tool holder 34, and allowing the tool holder 34 to be disengaged when the tool 25' or 25” has been replaced. Advantageously, the radial portion of the notch 350 is shaped to match the shape of the spindle 24' when the tool 25' or 25” is replaced.

[0063] More generally, it should be noted that the embodiments and examples considered above are described by way of non-limiting examples and that other alternatives are therefore possible.

Claims

1. A numerically controlled machine tool (10), characterized in that: The numerically controlled machine tool (10) comprises a multi-spindle turret (20) provided with a body (21) extending along an axis AA between a first end and a second end, by means of which the body (21) is fastened to a frame (11) of the machine tool (10), and at which the body (21) comprises a rotatable head (23), the head (23) comprising at least two tool holding spindles (24, 24', 24"), each of which is intended to receive in engagement a cutting tool (25, 25', 25"), the spindles (24, 24', 24") occupying, depending on the angular position of the head (23), either a working position in which they are intended to perform a machining operation on a workpiece held in position in a fixture, or a standby position in which they are withdrawn from the workpiece, the spindles (24, 24') being adapted to move the workpiece in the working position. , 24"), each of which is configured to be controlled independently of the other spindles so as to drive the tool (25, 25', 25") carried by it in a fixed or rotatable manner, regardless of the position occupied by the spindles, the machine tool (10) also comprising a tool holding device (30) configured to interact with the spindles (24', 24") in a standby position so as to remove the tool (25', 25") carried by the spindles (24', 24") for storage thereof and to insert a replacement tool (25'") into the spindles (24', 24"), the holding device (30) comprising a tool holder (34) held in a cantilevered position by a support structure (31) fastened to the body (21) of the turret (20), the tool holder (34) comprising a storage bucket (340) having a rotational degree of freedom about an axis CC.

2. The machine tool (10) according to claim 1, characterized in that The tool holder (34) is configured such that the axis CC is parallel to the longitudinal axis B'-B' or B"-B" of the spindle (24', 24") in the standby position interacting with the tool holder (34), and the storage barrel (340) and the spindle (24', 24") are capable of translating relative to each other along the axis CC.

3. The machine tool (10) according to claim 1 or 2, characterized in that: The knife seat (34) has at least one degree of translational or rotational freedom, thereby allowing the knife seat (34) to move between the following positions: an operating position in which the tool holder (34) is in close proximity to the spindle (24', 24") with which it is configured to interact, and a disengaged position in which the blade seat (34) is further away from the axis AA than when it is in the operating position.

4. The machine tool (10) according to claim 3, characterized in that The support structure (31) comprises a coupling member (32) which is fastened to the body (21) of the turret (20) and is connected to the knife seat (34) by an arm (33) which is configured to move the knife seat (34) between its operating position and its disengaged position.

5. The machine tool (10) according to claim 4, characterized in that The arm (33) has a distal portion (330) fastened to the blade seat (34), and the distal portion (330) is connected to a proximal portion (331) fastened to the coupling member (32) by a slide or a pivot.

6. The machine tool (10) according to claim 4 or 5, characterized in that Comprising at least two spindles (24', 24") occupying a standby position, the coupling member (32) is fastened to the body (21) of the turret (20) so as to be rotatable about the axis AA in order to drive the tool holder (34) from one of the spindles (24', 24") occupying the standby position to the other.

7. The machine tool (10) according to claim 4 or 5, characterized in that The tool holder (34) has a certain degree of translational mobility relative to the coupling member (32) along an axis parallel to the axis AA, so as to move the tool holder further away from the turret head when it occupies the disengaged position.

8. The machine tool (10) according to claim 4 or 5, characterized in that The coupling member (32) is fastened to the body (21) of the turret (20) so as to be able to slide along the axis AA in order to move the tool holder further away from the head of the turret when the tool holder occupies the disengaged position.

9. The machine tool (10) according to claim 1 or 2, characterized in that: The tool holder (34) comprises a protective shell (35) provided with a notch (350) comprising an axial portion and a radial portion, thereby allowing both the spindle (24', 24") and the tool (25', 25") to be stored to be inserted into the tool holder (34), and allowing the tool holder (34) to be detached when the tool (25', 25") has been replaced.

10. The machine tool (10) according to claim 9, characterized in that The radial portion of the notch (350) is shaped to match the shape of the spindle (24', 24") when the tool (25', 25") is replaced.

Images