Machining machine

Abstract

The invention relates to a machine tool for machining a piece, comprising a machine frame (1) and a tool spindle (2) designed to carry a tool (2a). The machine tool also comprises a main workpiece holder (3) designed to hold a workpiece (4), movable translationally with respect to the tool spindle along three axes X, Y and Z that are not parallel to each other and rotationally along an axis B, the main workpiece holder (3) being mounted on a carriage (5b) integral with a hollow shaft (5a) rotationally movable about the axis B. The machine tool also comprises an auxiliary workpiece support (6) that can be actuated by a control device between an engaged position in contact with the workpiece (4) and a disengaged position not in contact with the workpiece. Notably, the machine tool also comprises a finishing unit (10) housed at least partially in the hollow shaft (5a) and extending through an opening (5c) in the carriage (5b), said finishing unit (10) comprising a sliding rod (11) movable translationally along the axis B between a retracted position and an extended position, the auxiliary workpiece support (6) being kinematically connected to the sliding rod (11).

Description

Technical Field

[0001] This invention relates to a machine tool. More specifically, this invention relates to a machine tool comprising a finishing unit for performing machining of a workpiece on the same machining spindle. Existing technology Machining a workpiece in a machine tool requires rigidly holding the workpiece in a workpiece holder during material removal operations. The portion of the workpiece held in place is inaccessible for machining. To perform finishing work on the workpiece without having to transfer it to another machining station, a re-machining device must be incorporated into the machine tool itself to modify the workpiece clamping and make the final surface accessible.

[0002] Application EP1175278 discloses a machine tool suitable for machining parts, which includes a first workpiece holder and a movable device equipped with a fixture for clamping the machined part and performing additional machining operations. However, such a device occupies a lot of space and is not easy to adapt, especially in miniature machine tools with limited machining area.

[0003] Application EP4461458 discloses a five-axis micromachining machine tool including an auxiliary workpiece holder equipped with a clamp designed to hold the workpiece to be machined at the end of a bar. The auxiliary workpiece holder is fixed to a Y-axis slider and has no specific kinematic characteristics. This configuration utilizes the existing rotation of the main workpiece holder to a 90° transfer position, where the workpiece can be held by the clamp of the auxiliary workpiece holder. The bar can then be cut and the final face finished. Although achievable within the working volume of a micromachining machine, this solution has several limitations. The auxiliary workpiece holder is permanently held in the working volume and restricts the rotation of the workpiece carriage about the B-axis. Machining is performed when the workpiece and tool are between the open jaws of the auxiliary workpiece holder's clamp, which requires a large clamp opening, restricts tool movement around the workpiece, and increases the risk of collision. The permanent presence of the chuck near the workpiece also limits accessibility for loading and unloading, maintenance, or visual inspection of the workpiece. Once the part has been transferred to the auxiliary workpiece holder, the final stage of the machining operation is performed only on the three translation axes, with the final face in an unfavorable position parallel to the machining spindle, which greatly limits the possibility of producing complex geometries.

[0004] Applications US2015367468 and EP4299242 describe a five-axis machining center in which a rotary support is designed to hold the workpiece on the support while allowing it a certain degree of rotational freedom. This allows for workpiece contouring. The rotary support is mounted on the machine tool carriage, which has the disadvantage of increasing its inertia and occupying space in the work area.

[0005] The purpose of this invention is to overcome the various shortcomings of the prior art in order to improve the integration of auxiliary workpiece supports in multi-axis machining centers, especially micro-machining machines with reduced workspace. Summary of the Invention

[0006] The objective of this invention is achieved by a machining tool comprising: frame, Tool spindle, which is designed to carry the tool. A main workpiece retainer, designed to hold the workpiece, is capable of translational movement relative to the tool spindle along three non-parallel axes X, Y, and Z, and rotational movement along axis B. The main workpiece retainer is mounted on a bracket integral with a hollow shaft, which is capable of rotational movement about axis B. An auxiliary workpiece support is provided, which can be actuated by a control device between an engaged position in contact with the workpiece and a disengaged position not in contact with the workpiece. The machine tool according to the invention also includes a finishing unit at least partially housed in a hollow shaft and extending through an opening in a bracket, the finishing unit including a sliding rod capable of translating along axis B between a retracted position and an extended position, the auxiliary workpiece support being kinematically connected to the sliding rod.

[0007] This arrangement allows for the combination of an auxiliary workpiece holder to perform remapping operations on the same machining spindle. Because the auxiliary workpiece holder retracts and the finishing unit is integrated into the rotary axis without taking up workspace, the impact on machining capacity and accessibility of the machining area is limited when the auxiliary workpiece holder is not in use.

[0008] On one advantage, the auxiliary workpiece support is mounted on the sliding rod.

[0009] This arrangement allows the auxiliary workpiece support to be positioned close to the workpiece held in the main workpiece holder, and also allows the auxiliary workpiece support to retract so as not to interfere with the initial machining operation.

[0010] On one advantage, the auxiliary workpiece support is mounted on the bracket.

[0011] In this configuration, the sliding rod constitutes a control device that allows the auxiliary workpiece support to engage with and disengage from the workpiece.

[0012] From one advantageous perspective, the X-axis, Y-axis, and Z-axis are perpendicular, with the Z-axis being vertical.

[0013] On one hand, the B-axis is parallel to the Y-axis.

[0014] According to an advantageous aspect, the tool spindle is mounted on a first slider that is movable relative to a second slider along the Z-axis, the second slider being movable relative to the frame along the X-axis, and wherein the hollow shaft is mounted such that it is rotatable on a third slider that is translatably movable relative to the frame along the Y-axis.

[0015] According to one advantageous aspect, the main workpiece retainer is fixed to the workpiece spindle, which is mounted on a bracket and is capable of rotating about an axis C perpendicular to axis B.

[0016] According to one advantageous aspect, the auxiliary workpiece support is an auxiliary workpiece holder that includes a clamping device capable of clamping the workpiece held in the main workpiece holder when the sliding rod is in the extended position and the bracket is in the transfer position.

[0017] This arrangement allows the workpiece to be transferred to an auxiliary workpiece holder for finishing.

[0018] According to a particularly advantageous aspect, the finishing unit includes a pivoting device that enables the sliding rod to pivot rotatably about axis B between a transfer orientation and a machining orientation at predetermined values ​​spaced between 0° and 180°.

[0019] This arrangement allows the workpiece to be completely flipped so that the final face to be machined is in optimal orientation relative to the tool spindle.

[0020] According to an advantageous aspect of the invention, when the sliding rod is in its extended position, the sliding rod is in a transfer orientation, and when the sliding rod is in its retracted position, the sliding rod is in a processing orientation.

[0021] According to an advantageous aspect of the invention, the pivoting device defining the angular position of the sliding rod relative to the bracket consists of a cam and a cam follower, one of which is integral with the sliding rod and the other with the bracket.

[0022] According to an advantageous aspect of the invention, the auxiliary workpiece support is a blank holder designed to be supported on the workpiece.

[0023] According to another advantageous aspect of the invention, the auxiliary workpiece support is a rotating support designed to support a workpiece for turning.

[0024] This arrangement allows for finishing operations to be performed on the workpiece. Attached Figure Description

[0025] Further details of the invention will become clearer upon reading the following description with reference to the accompanying drawings, in which: Figure 1 A view of the main components of the machine tool according to the present invention is shown. Figure 2 An exploded view of the elements of the present invention is shown. Figures 3 to 5 A first embodiment of the invention in three consecutive states is shown. Figures 6 to 8 The finishing unit of the first embodiment is shown in the folded position, the intermediate position, and the extended position, respectively. Figure 9 and Figure 10 The second embodiment of the invention is shown in both the folded and extended positions. Figures 11 to 12 The third embodiment of the invention is shown in both the folded and extended positions. Detailed Implementation

[0026] The present invention relates to a machine tool comprising at least four machining axes, namely three translational axes and at least one rotary axis. Figure 1 A view of the main components of this type of machine tool is shown. The structure is designed to be housed in a protective housing and to operate in conjunction with various feeding and control devices.

[0027] The machine tool includes a frame 1, the high rigidity of which contributes to machining accuracy and repeatability. The frame 1 is mounted on a support 1a. The machine tool also includes a tool spindle 2 designed to carry a tool 2a via a tool holder 2b, and a main workpiece holder 3 designed to hold a workpiece 4. The main workpiece holder 3 is movable relative to the tool spindle 2 according to at least four degrees of freedom: three translational degrees of freedom along three non-parallel axes X, Y, and Z, and at least one rotational degree of freedom along axis B. For this purpose, the main workpiece holder 3 is mounted on a bracket 5b integral with a hollow shaft 5a, which is rotatably movable about axis B. Figure 2 As can be seen in the text.

[0028] In the example shown, the X-axis, Y-axis, and Z-axis are perpendicular to each other, with the Z-axis being vertical, and therefore the X-axis and Y-axis are horizontal. The B-axis is parallel to the Y-axis. According to the specific configuration shown, the tool spindle 2 is mounted such that it can translate relative to the frame 1 along the X-axis and Z-axis. The tool spindle 2 is mounted on a first slider 7a, which is movable relative to a second slider 7b along the Z-axis, and the second slider is movable relative to the frame 1 along the X-axis. The main workpiece holder 3 is mounted on a bracket 5b integral with the hollow shaft 5a, which is itself mounted to be rotatably movable relative to a third slider 7c, which is movable relative to the frame 1 along a horizontal Y-axis perpendicular to the X-axis. In the example shown, the B-axis is parallel to the Y-axis, with the hollow shaft 5a mounted such that it pivots in the third slider 7c, allowing the main workpiece holder to rotate and translate relative to the frame along the B-axis. Of course, the invention is not limited to this specific machine tool architecture; the three sliding elements providing three translational movements can, for example, be mounted in series between the frame and the tool spindle.

[0029] In the illustrated embodiment, the machine tool also has a fifth machining axis. In this case, the main workpiece holder 3 is not integrated with the bracket 5b, but is attached to the workpiece spindle 8, which is mounted on the bracket 5b and is capable of rotating about an axis C perpendicular to axis B.

[0030] In order to complete the machining of workpiece 4 without having to transfer it to another station, the machine tool also includes an auxiliary workpiece support 6. The auxiliary workpiece support 6 can be actuated by a control device between an engaged position in contact with workpiece 4 and a released position not in contact with workpiece 4. Depending on the type of machining to be performed to finish the workpiece, the auxiliary workpiece support 6 can take several forms.

[0031] The machine tool also includes a finishing unit 10, at least partially housed in a hollow shaft 5a and extending through an opening 5c ​​in a bracket. The finishing unit 10 includes a sliding rod 11, which is translatably movable along axis B between a retracted position and an extended position. In a first embodiment, an auxiliary workpiece support 6 is mounted on the sliding rod 11. When the sliding rod 11 is in the retracted position, as... Figure 1 , Figure 3 , Figure 9 and Figure 11 As can be seen, the auxiliary workpiece support 6 is positioned rearward and does not interfere with the relative movement of the tool and workpiece during the first machining stage. This auxiliary workpiece support also does not restrict the angular amplitude of the bracket's rotation about axis B or the accessibility of the machining area. Furthermore, the finishing unit extending along axis B has only a slight effect on the moment of inertia of the assembly rotating about axis B.

[0032] exist Figures 3 to 8 In the first embodiment shown, the auxiliary workpiece support 6 is an auxiliary workpiece holder 6a, which includes a clamping device, typically a clamp that can be actuated by a control device to control its opening and closing. Once the sliding rod 11 is in the extended position and the main workpiece holder 3 is in a predetermined transfer position, the auxiliary workpiece holder 6a is able to grip the workpiece held in the main workpiece holder 3. In the example shown, the transfer position corresponds to a 90° tilt of the bracket 5b, such as... Figure 3 and Figure 4 The structure is shown. Therefore, a suitable tool can be used to cut the workpiece held in both workpiece holders, with the final workpiece retained in the auxiliary workpiece holder 6a. The portion retained in the main workpiece holder 3 can be removed, or, in the case of a bar, moved through the main workpiece holder 3 to begin a new workpiece. When the slider 11 returns to... Figure 5 When it is in the retracted position as shown, the auxiliary workpiece holder 6a is able to hold the workpiece 4 so that the final surface can be machined and the fully finished workpiece can be removed.

[0033] Figures 6 to 8 The finishing unit 10 is shown at different positions of the sliding rod 11. The finishing unit 10 is attached to the bracket 5b by means of a cover 10c, such that the finishing unit 10 is at least partially housed in the hollow shaft 5a and extends through the opening 5c ​​of the bracket in the direction of axis B. The cover 10c is integral with the cylindrical body 10b, at the end of which an actuator 10a, typically a motor or cylinder, is attached. The actuator 10a is arranged to move the sliding rod 11 within the cylindrical body 10b by means of a rod 11b, such that the sliding rod 11 can move along axis B. Figure 6 and Figure 8 The retracted and extended positions shown in the figure are translated between each other, where Figure 7 The middle position is shown.

[0034] Openings 11c and 11d are provided in the sliding rod 11 for the passage of a flexible element, which supplies a control device to actuate the auxiliary workpiece holder 6a to clamp, hold, or release the workpiece 4.

[0035] A stop 10e is provided to limit the travel of the sliding rod, and the auxiliary component support is precisely and repeatably positioned in the translation and rotation directions in the folded and unfolded positions of the sliding rod 11.

[0036] In the first embodiment, the sliding rod 11 is also rotatable about axis B, thereby forming a sliding pivot connection with the cylindrical body 10b. Furthermore, the finishing unit includes a pivoting device that enables the sliding rod 11 to pivot rotatably about axis B between a predetermined transfer orientation and a processing orientation spaced between 0° and 180°.

[0037] In the example shown, when the slider 11 is in its extended position and its transfer orientation, the slider is in its transfer position, and when the slider is in its retracted position and its machining orientation, the slider is in its machining position.

[0038] The pivoting mechanism can take several forms. A rotary cylinder mounted in series on a linear actuator, or a combination of rotary electromagnetic linear actuators, can be provided. The sliding and pivoting connection of the sliding rod 11 relative to the cylindrical body 10b can also be connected to form, for example, a helical connection.

[0039] In the example shown, the translational and rotational degrees of freedom of the sliding rod 11 relative to the cylindrical body 10b, and therefore relative to the bracket 5b integral with the cylindrical body, are linked by a cam system. The pivoting mechanism defining the angular position of the sliding rod 11 relative to the bracket 5b consists of a cam 11a and a cam follower 10d, one integral with the sliding rod and the other with the bracket. In the specific embodiment shown, the cam 11a is a groove formed on the sliding rod 11, in which the end of the pin 10d, fixed to the cylindrical body 10b, is received. A groove can also be easily formed in the inner wall of the cylindrical body 10b, and the pin is fixed to the sliding rod 11. By moving the sliding rod along axis B from an extended position to a retracted position, the pin 10d follows the cam path formed by the groove 11a, which forces the sliding rod 11 to pivot about axis B by a predetermined amount defined by the shape of the cam. In the example shown, the cam is arranged such that the sliding member is spaced 90° apart about axis B in its extended and retracted positions.

[0040] The rotation of the sliding rod 11, combined with its translation along axis B, explains the function of the auxiliary workpiece holder 6a. Figure 4 The extension position of the sliding rod shown and Figure 3 and Figure 5 The orientation change between its retracted positions is shown. Adding the rotation of bracket 5b to the transfer position and the rotation of the sliding rod when it returns to its folded position, the orientation change of workpiece 4 relative to its folded position is obtained. Figure 1 The total rotation of 180° from its original position is shown. The complete reversal of the workpiece allows the final face to be machined to be presented in an optimal orientation orthogonal to the machining spindle 2, and therefore when the sliding rod 11 is in... Figure 5 When folded as shown, it is possible to perform full machining along the four axes X, Y, Z and B.

[0041] Those skilled in the art will know how to modify the machine tool settings according to the geometry of the workpiece. To increase the angular amplitude of the carriage when machining the final surface, a specific transfer angle can be provided, the value of which is within the tilt amplitude of the carriage 5b, approximately ±120°. For example, a transfer angle of 60° can be set, and a 120° slider rotation can be set between the transfer orientation and the machining orientation.

[0042] The finishing unit 10, equipped with a retractable auxiliary workpiece support, is installed in the hollow shaft 5a, which allows the workpiece to be finished by utilizing all the degrees of freedom of the machine tool (including rotation about axis B) without significantly affecting the initial machining capability in terms of the range of relative motion between the tool and the part, the accessibility of the machining area, and the inertia of the carriage.

[0043] Figure 9 and Figure 10 A second embodiment of the invention is shown, wherein the auxiliary workpiece support 6 is a blank holder 6b designed to rest on a workpiece 4 mounted on the main workpiece holder 3. The blank holder allows a portion of the workpiece to be supported so as to hold it in place and allow for processing of areas that are still accessible. In the second embodiment, the blank holder 6b is mounted at the end of a sliding rod 11, which is movable parallel to axis B between a retracted position and an extended position. Once the sliding rod is in... Figure 10 The extended position shown is driven by a cylinder 12 actuated by a control device located in the recovery module, which drives the flange 13 on which the blank holder 6b is mounted. In the example shown, the flange 13 is mounted on a deformable parallelogram, such that the contact surfaces of the blank holder and the workpiece 4 remain parallel. Therefore, the blank holder 6b can move in a circular translation with a component orthogonal to the workpiece mounting plane until it contacts the workpiece. Other solutions are possible; the blank holder can simply pivot at the end of the sliding rod, and its rotation is controlled by the cylinder 12. In this case, the blank holder will have a circular trajectory, which also has a component orthogonal to the plane of the workpiece.

[0044] Figure 11 and Figure 12 A third embodiment of the invention is shown, wherein the auxiliary workpiece support is a rotating support 6c designed to support a workpiece for turning. The main workpiece retainer 3 is mounted on the workpiece spindle 8 and is driven to rotate about axis C. The main workpiece retainer 3 holds the workpiece 4 when the auxiliary workpiece support is in such a position as... Figure 11In the retracted position shown, various machining operations can be performed on the workpiece. To obtain a rotating surface around the circumference of the workpiece, the workpiece is cut by rotating it against the chisel tool 2a. During the cutting operation, the workpiece needs to be held in a manner similar to that of the blank holder 6b, using an auxiliary workpiece support that applies pressure perpendicular to the mounting plane. As the part rotates, the rotating support 6c rotates freely about axis C. A short-stroke cylinder 14 is mounted at the end of the sliding rod 11 to move the rotating support 6c orthogonally to the mounting plane until it contacts the part to be machined.

[0045] In the presented example, a specific control device is used to actuate the auxiliary workpiece support. In an alternative solution not shown, the control device is directly a sliding rod 11, and the workpiece support is actuated by the relative movement of the sliding rod relative to the bracket. The workpiece support can, for example, pivot on the sliding rod or be mounted on a similar... Figure 9 and Figure 10 On the flange 13 shown, the flange is kinematically connected to the bracket, such that movement of the sliding rod causes movement of the workpiece support and engagement with the workpiece. In the case of a fixture, the machine tool can be arranged such that movement of the sliding rod toward its extended position causes movement and closure of the fixture. Conversely, the workpiece support can be mounted on the bracket and kinematically connected to the sliding rod. In the case of a blank holder, it can be actuated by the sliding rod so as to engage with the workpiece when the sliding rod moves. Thus, the blank holder can pivot on the sliding rod and be kinematically connected to the bracket, or conversely, pivot on the bracket and be kinematically connected to the sliding rod. In the example shown, the extended position of the sliding rod corresponds to the position where the workpiece support can engage with the workpiece. If the sliding rod is a device for controlling the workpiece support, the extended position of the sliding rod can correspond to the retracted position of the workpiece support, and the retracted position of the sliding rod can correspond to the engaged position of the workpiece support.

[0046] The various examples presented illustrate, in a non-limiting manner, different solutions for integrating the auxiliary workpiece support 6 into the core of a multi-axis machine tool to perform finishing operations on the workpiece, utilizing all machine tool axes while having minimal impact on machining capabilities and accessibility to the machining area when only the main workpiece holder 3 is used.

Claims

1. A machine tool for machining workpieces, the machine tool comprising: Rack (1), Tool spindle (2), which is designed to carry the tool (2a). A main workpiece holder (3), designed to hold a workpiece (4), is capable of translational movement relative to the tool spindle along three non-parallel axes X, Y, and Z and rotational movement along axis B. The main workpiece holder (3) is mounted on a bracket (5b) integral with a hollow shaft (5a) capable of rotation about axis B. An auxiliary workpiece holder (6) is operable via a control device between an engagement position in contact with the workpiece (4) and a disengagement position not in contact with the workpiece. The machine tool further includes a finishing unit (10) that is at least partially housed in the hollow shaft (5a) and extends through an opening (5c) in the bracket (5b). The finishing unit (10) includes a sliding rod (11) that is translatably movable along axis B between a folded position and an unfolded position. The auxiliary workpiece support (6) is kinematically connected to the sliding rod (11).

2. The machine tool according to claim 1, wherein the auxiliary workpiece holder (6) is mounted on the sliding rod (11).

3. The machine tool according to claim 1, wherein the auxiliary workpiece holder (6) is mounted on the bracket (5b).

4. The machine tool according to claim 1, wherein the X-axis, Y-axis and Z-axis are perpendicular, and the Z-axis is vertical.

5. The machine tool according to claim 1, wherein the B-axis is parallel to the Y-axis.

6. The machine tool according to claim 1, wherein the tool spindle (2) is mounted on a first slider (7a) movable relative to a second slider (7b) along the Z-axis, the second slider movable relative to the frame (1) along the X-axis, and wherein the hollow shaft (5a) is mounted to be rotatable on a third slider (7c) movable relative to the frame (1) along the Y-axis.

7. The machine tool according to claim 1, wherein the main workpiece holder (3) is attached to the workpiece spindle (8), the workpiece spindle being mounted on the bracket (5b) and rotatable about an axis C perpendicular to axis B.

8. The machine tool according to claim 1, wherein the auxiliary workpiece support (6) is an auxiliary workpiece holder (6a), the auxiliary workpiece holder including a clamping device capable of clamping a workpiece held in the main workpiece holder (3) when the sliding rod (11) is in the unfolded position and the bracket (5b) is in the transfer position.

9. The machine tool according to the preceding claim, wherein the finishing unit (10) includes a pivoting device that enables the sliding rod (11) to pivot rotatably about the B axis between a transfer orientation and a machining orientation spaced apart by a given value between 0° and 180°.

10. The machine tool according to the preceding claim, wherein the sliding rod (11) is in the transfer orientation when in its extended position and in the machining orientation when in its folded position.

11. The machine tool according to the preceding claim, wherein the pivoting device defining the angular position of the sliding rod (11) relative to the bracket consists of a cam (11a) and a cam follower (10d), one of the cam and the cam follower being integral with the sliding rod (11) and the other being integral with the bracket (5b).

12. The machine tool according to claim 1, wherein the auxiliary workpiece support (6) is a blank holder (6b) designed to be supported on the workpiece.

13. The machine tool according to claim 7, wherein the auxiliary workpiece support (6) is a rotary support (6c) designed to support a workpiece for turning.

14. The machine tool according to claim 10, wherein actuation of the control device causes displacement of the auxiliary workpiece support (6, 6b, 6c), the displacement having a component orthogonal to the positioning plane of the workpiece.

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