Numerical control machine tools for machining minute machine parts from semi-finished products in the form of rods or strips.

Abstract

To provide a numerically controlled machine tool for machining micromechanical parts from a blank in the form of a bar or strip.SOLUTION: A numerically controlled machine tool (10) is provided for machining micromechanical parts from a blank (100) in the form of a bar or strip, the numerically controlled machine tool (10) including a frame (12), a part carrier unit (11) intended to hold the part (100) in position and a tool carrier unit (13) intended to carry a cutting tool (130), the part carrier unit (11) being kinematically connected to the frame (12) so as to have, with respect to the frame (12), only one rotational degree of freedom and one translational degree of freedom in a direction Z, in a reference system XYZ, and the tool carrier unit (13) being kinematically connected to the frame (12) so as to have, with respect to the frame (12), only one translational degree of freedom in a direction X, and one rotational and translational degree of freedom in a direction Y.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention lies within the field of numerically controlled machine tools, and more particularly relates to numerically controlled machine tools for machining micro mechanical parts from semi-finished products in the form of bars or strips.

[0002] In the present text, the term "bar" means any solid or hollow wire, profile or tube, regardless of its cross-sectional shape.

Background Art

[0003] In the field of micromechanics, reducing the dimensions of numerically controlled machine tools, particularly reducing the size of the machine tool relative to the machined volume, brings several advantages, including an increase in cutting speed and cutting tool movement speed due to a reduction in the inertia of the moving mass, a reduction in the floor space required for storing the machine tool, and a reduction in the energy consumption of such a machine tool.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, reducing the dimensions of a machine tool may involve a loss of static rigidity of the machine tool. That is, the components forming the machine tool become more prone to deformation, which is not favorable for high-precision machining required in microtechnology applications such as watch manufacturing.

[0005] The concept of "rigidity of a machine tool" in the field of mechanics characterizes the dimensional stability of the components forming the machine tool under the influence of thermal gradients or mechanical stresses, particularly the dimensional stability of the components forming the kinematic path, i.e., the force loop, between the part to be machined and the cutting tool passing through the components forming the machine tool.

Means for Solving the Problems

[0006] The present invention overcomes the aforementioned drawbacks and, for this purpose, relates to a numerically controlled machine tool for machining minute machine parts from semi-finished products in the form of rods or strips, wherein the numerically controlled machine tool comprises a frame, a part support unit intended to hold the part in place, and a tool support unit intended to support a cutting tool.

[0007] In this text, the term "cutting tool" refers to any tool used to remove material from a part, whether it is a fixed tool such as a turning tool or a rotating tool such as a milling tool.

[0008] The component support unit is kinematically connected to the frame such that it has a rotational-translational degree of freedom of 1 degree in direction Z in the coordinate system XYZ. The tool support unit is kinematically connected to the frame such that it has a translational degree of freedom of 1 degree in direction X and a rotational-translational degree of freedom of 1 degree in direction Y.

[0009] In this text, the term "direction" refers to an axis extending in a given direction. For example, direction X refers to axis X or an axis parallel to axis X.

[0010] Advantageously, the present invention enables the optimization of the ratio between the size of the machine tool and the size of the semi-finished product, and more specifically, enables the minimization of the dimensions of the machine tool and / or the maximization of the dimensions of the semi-finished product.

[0011] For example, a machine tool may be designed such that its volume is substantially five times larger than the volume of its machining area, and the volume of the workpiece before machining may be at least five times larger than the volume of the machining area. Therefore, the ratio of the machine tool's volume to the workpiece's volume may be equal to 1.

[0012] In certain embodiments, the present invention may further include one or more of the following features, taken individually or in any technically possible combination:

[0013] In certain embodiments, the component support unit includes a component support carriage connected to the frame by at least one sliding body fixed directly to the frame, the component support carriage includes a component support module, the component support module is adaptable to a fastened state in which the component support module holds a component in place, or a released state in which the component support module allows movement of the component.

[0014] In certain embodiments, the part support carriage has a through-opening extending in direction Z, opening at one end of the part support module, the opening intended to receive a part for supply to the machining area of ​​a machine tool.

[0015] In certain embodiments, the tool support unit includes a first carriage connected to a frame by at least one sliding body, the at least one sliding body being directly fixed to the frame and extending in direction X. The tool support unit includes a second carriage, the second carriage being connected to the first carriage and comprising a tool support, the tool support being capable of rotational and translational movement in direction Y.

[0016] In certain embodiments, the second carriage is mounted on at least one sliding body, the at least one sliding body is fixed to the first carriage extending in direction Y, and the tool support is rotatable relative to the second carriage.

[0017] In certain embodiments, the machine tool includes a further unit, which is kinematically connected to the frame such that it has only one rotational-translational degree of freedom in the Z direction. The further unit is configured such that a cutting tool is interposed between the part support unit and the further unit, and the further unit includes a further carriage, which is positioned opposite the part support unit and receives a pair of part support modules, the pair of part support modules receiving a second tool support intended to fix or release a part or to support a cutting tool.

[0018] In certain embodiments, a further carriage has a through-opening extending in the Z direction, opening into one end of the pair of component support modules, the through-opening being intended to receive components for removal from the machining area of the machine tool.

[0019] In certain embodiments, the further carriage is assembled on at least one slider fixed to the frame, and the slider on which the component support carriage and the further carriage are connected is formed by the same slider.

[0020] In certain embodiments, the component support module and the pair of component support modules may include positioning devices intended for guiding the components when the components move or for holding the components in a predetermined position.

[0021] In certain embodiments, the machine tool includes a second tool support unit similar to the tool support unit, the second tool support unit being arranged symmetrically to the tool support unit with respect to the symmetry plane YZ, and the tool support units are each on either side of either the component support unit or the further unit.

[0022] Other features and advantages of the present invention will become apparent from the following detailed description, presented as a non-limiting example while referring to the drawings.

Brief Description of the Drawings

[0023] [Figure 1] FIG. 1 is a perspective view of a variant of a machine tool according to a preferred embodiment of the present invention, the semi-finished product to be machined being in the form of a bar. [Figure 2] FIG. 2 is a perspective view of another variant of the machine tool of FIG. 1, the semi-finished product to be machined being in the form of a strip. [Figure 3] FIG. 3 is a front view of the machine tool of FIG. 1. [Figure 4] FIG. 4 is a sectional view of the machine tool of FIG. 3 along the detail axis A-A.

Embodiments for Carrying out the Invention

[0024] It should be noted that the drawings are not necessarily drawn to scale for clarity.

[0025] The numerically controlled machine tool 10 according to the present invention is adapted to machine micro mechanical parts from semi-finished products to be machined, and the semi-finished products are in the form of a bar as shown in FIG. 1 or in the form of a strip as shown in FIG. 2. In a manner known to those skilled in the art, the machine tool 10 includes a monitoring and control unit such as a microcontroller, and the monitoring and control unit is intended to receive instructions in the form of a computer program and control the components of the machine tool 10 according to these instructions. Since the driving of various components of the machine tool 10 is within the scope of those skilled in the art and is thus not the subject matter of the present invention, these aspects will not be described in too much detail in this text.

[0026] In a preferred application of the present invention, the machine tool 10 is adapted to obtain parts specific to the field of watch manufacturing. The parts are, in particular, push pieces, screws, mandrels, pins, etc. when the semi-finished product is in the form of a bar, and receivers, plates, rockers, intermediate plates, templets, band connectors, etc. when the semi-finished product is in the form of a strip. The semi-finished product is moved so as to be sent to the machining area of the machine tool 10 in order to successively machine the parts from the semi-finished product. For the sake of simplicity in reading this text, the semi-finished products and parts to be machined, or the semi-finished products and parts for which machining has been completed, are referred to by the same term "parts" 100.

[0027] As shown in the drawings, the machine tool 10 includes, in particular, a part support unit 11 intended to hold the part 100 in a predetermined position during machining. The part support unit 11 is kinematically connected to the frame 12 so as to have only one degree of rotational freedom and one degree of translational freedom in the direction Z in the normal orthogonal coordinate system XYZ. As shown in FIGS. 1 to 3, the part support unit 11 is configured to hold the part 100 in a predetermined position, and for this purpose, the part support unit 11 extends longitudinally in the direction Z. This feature enables the limitation of the inertia of the moving elements when the part support unit 11 moves.

[0028] The rotational degrees of freedom of the part support unit 11 are advantageous in that they allow the part support unit 11 to be driven to perform turning operations on the part 100 or to perform milling operations at various angular positions of the part 100. For example, the part support unit 11 may be configured to drive the part 100 to speeds exceeding 8000 rpm, for example, up to 20000 rpm, during turning operations. It goes without saying that turning operations are only suitable for part 100 in the form of a rod.

[0029] In this invention, the frame 12 is formed from rigid structural elements of the machine tool 10. Thanks to the features of this invention, the frame 12 can be made relatively small, as shown in the figure.

[0030] The machine tool 10 also includes a tool support unit 13, which supports a cutting tool 130 and is intended to be kinematically connected to the frame 12 such that it has only one translational degree of freedom in direction X, one rotational degree of freedom in direction Y, and one translational degree of freedom.

[0031] Therefore, the machine tool 10 includes five degrees of mobility, three of which are specific to the tool support unit 13 and two are specific to the part 100. Thus, the majority of the movement is performed by the assembly with the least mass, i.e., the tool support unit 13. Furthermore, as will be explained in more detail below, from a kinematic standpoint, we attempted to limit the number of translational degrees of freedom of the tool support unit 13 to 2 degrees in order to limit the total mass of the moving elements, and thus minimize the stresses associated with inertia, and to enable the use of relatively small connecting elements.

[0032] Overall, these configurations also minimize the number of connecting elements interposed between the tool support unit 13 and the component support unit 11 and the frame 12, which has the advantage of enabling a rigid machine tool 10 while minimizing the volume and mass of the machine tool 10.

[0033] In particular, the component support unit 11 includes a component support carriage 110 assembled on at least one sliding body 120 which is directly fixed to the frame 12. The component support carriage 110 includes a component support module 112 formed by, for example, a chuck as shown in Figures 1 and 3, or a placement device as shown in Figure 2. In a known form, the component support module 112 is adapted to a fastened state in which the component support module 112 holds the component 100 in place, or to a released state in which the component support module 112 allows the component 100 to move. The component support carriage 110 has a through-opening extending in direction Z, which is intended to guide the component 100 through the through-opening and feed it to the machining area of ​​the machine tool 10. Here, it should be understood that the opening is located at one end of the component support module 112.

[0034] Furthermore, the tool support unit 13 includes a first carriage 131 mounted on at least one sliding body 120, the at least one sliding body 120 being directly fixed to the frame 12 and extending in direction X. The tool support unit 13 also includes a second carriage 133 mounted on at least one sliding body 120, the at least one sliding body 120 being fixed to the first carriage 131 and extending in direction Y. The second carriage 133 includes a tool support 135 that can rotate around direction Y, such as a tool support spindle, as shown in Figures 1 to 4.

[0035] As shown in Figures 1 and 2, direction X is perpendicular, i.e., directed in the direction of gravity. Therefore, the first carriage 131 may be subjected to a greater force than the second carriage 133, insofar as the force is related to the mass of the elements supported by the first carriage 131 and the second carriage 133, respectively. The first carriage 131 is also configured to move further than the second carriage 133, in particular to remove the cutting tool 130 from the machining area.

[0036] Since the first carriage 131 is directly connected to the frame 12, the additional forces that the first carriage 131 experiences and the longer travel of the first carriage 131 are less likely to affect the rigidity of the machine tool 10 compared to the second carriage 133.

[0037] Here, it should be understood that the configuration of the degrees of freedom of the first carriage 131 and the second carriage 133 of the component support carriage 110 and the tool support unit 13 is particularly advantageous. This is because, on the one hand, this configuration allows for minimization of the mass of the moving elements, and therefore minimization of the stresses on the machine tool 10, and on the other hand, it allows these stresses to be transmitted to the frame 12 as directly as possible. Thanks to these features, the machine tool 10, in particular the tool support unit 13 and the component support unit 11, benefit from excellent dynamic behavior, suppression of the inertia of the moving elements, and increased rigidity of the machine tool 10.

[0038] Thanks to the design of the machine tool 10 according to the present invention, the sliding body 120 can be manufactured in a relatively small size.

[0039] These features also allow for the easy integration of protective walls (not shown) into the machine tool 10 to protect it from chips and machining lubricants released from the material. These protective walls are configured to form a machining chamber that is substantially sealed from the external environment. Furthermore, the machining chamber can be designed to be relatively compact by sealing and fixing the walls to the frame 12 on one side and to each carriage on the other, for example, with wipers 121 or bellows 122.

[0040] In particular, the bellows 122 is schematically shown in Figure 1 as transparent, especially to show the sliding body 120. Figures 3 and 4 show an example of the bellows 122 having two opposite deformable walls, one of which expands and the other retracts according to the position occupied by the carriage. Figure 4 also shows a wiper 121 attached around the tool support 135, in particular to the cylindrical portion of the tool support 135 extending in direction Y.

[0041] It should be noted that when the machine tool 10 is intended to perform a milling operation, the tool support 135 is configured to rotate the cutting tool 130, i.e., the milling cutter, around its longitudinal axis. This configuration can be implemented by commercially available solutions for those skilled in the art. For example, when performing a milling operation, the tool support 135 may be configured to rotate the cutting tool 130 around its longitudinal axis at a speed greater than 60,000 rpm, for example, 70,000 rpm.

[0042] The machine tool 10 may include an additional unit 14 that is kinematically connected to the frame 12 so as to have only one translational degree of freedom and one rotational degree of freedom in direction Z. Similar to the part support unit 11, as shown in Figures 1 and 2, this additional unit 14 includes an additional carriage 140 assembled on at least one sliding body 120, the at least one sliding body 120 being directly fixed to the frame 12. The additional unit 14 is arranged to be located on either side of the tool support unit 13 together with the part support unit 11. In other words, the cutting tool 130 is interposed between the part support unit 11 and the additional unit 14.

[0043] Advantageously, the sliding body 120 to which the component support carriage 110 and the further carriage 140 are connected can be formed from the same sliding body. Advantageously, this feature ensures alignment between the component support carriage 110 and the further carriage 140.

[0044] The additional carriage 140 is adapted to receive a pair of part support modules 141 or a second tool support (not shown) positioned opposite the part support unit 11. The additional carriage 140 is intended to hold the part 100 in place if the additional carriage 140 includes a pair of part support modules 141, and to machine the part 100 held by the part support module 112 by milling or drilling if the additional carriage 140 includes a second tool support.

[0045] In particular, the pair of component support modules 141 can be formed in the same manner as described above, for example, by clamps or mandrels shown in Figure 1, or by a mating device shown in Figure 2.

[0046] Similar to the part support carriage 110, the further carriage 140 has a through-opening 142 which extends in direction Z and opens to one end of a pair of part support modules 141. The part 100 is intended to be guided through the through-opening 142 to be removed from the machining area of ​​the machine tool 10.

[0047] Advantageously, in the example shown in Figure 1, the pair of part support modules 141 can be controlled to grip the part 100 held by the part support carriage 110, particularly part support module 112, so that after the part is released by the part support module 112, it is fixed in place only by the pair of part support modules 141, allowing a new machining step to be performed. During this new machining step, the cutting tool 130 can then access areas of the part 100 that were inaccessible when the part 100 was held in place by the part support module 112, and thus the machining can be completed.

[0048] Furthermore, in the example shown in Figure 2, the component 100, which is in this case a strip, may be advantageously held simultaneously by the component support module 112 and the pair of component support modules 141. Such a placement device is also intended, for example, to guide the component 100 as it moves, in combination with a component support placement device. For this purpose, the placement device includes a guide path that cooperates with the component 100 and fastening means that are suitable for fixing or releasing the component 100.

[0049] In this exemplary embodiment of the present invention, the part support module 112 and the pair of part support modules 141 can control the movement of the part 100 in a feed movement, i.e., the part 100 is translated in only one direction, direction Z. This feed movement of the part 100 is performed, for example, before a machining step and at the end of a machining step, to result in the inflow of the part 100 in the form of a raw part and the outflow of the part 100 in the form of a machined part from the machine tool 10. More specifically, in order to move the part 100 in this feed movement, for example, the part support module 112 or the pair of part support modules 141 is driven to hold the part 100, while the other module is driven to release the part 100, and then the module holding the part translates in direction Z in a given orientation. Then this module is driven to release the part 100, while the other module is driven to hold the part.

[0050] The part support module 112 and the pair of part support modules 141 can also be driven to move the part 100 during the machining process. More specifically, the part support module 112 and the pair of part support modules 141 are both driven in this case by the same translational, possibly rotational, motion, and in particular to tilt the part 100 in direction Z when the part 100 is in the form of a rod.

[0051] When the additional carriage 140 receives the second tool support, the second tool support is adapted to support a cutting tool such as a milling tool or a turning tool, so that the additional unit 14 can perform turning and milling operations on the part fixed by the tool support module 112.

[0052] As shown in Figures 1 and 2, in a preferred embodiment of the present invention, the component support carriage 110, the first carriage 131, the second carriage 133, and the further carriage 140 are supported by two sliding bodies 120.

[0053] Advantageously, the machine tool may include a second tool support unit similar to the tool support unit 13, the second tool support unit being symmetrically positioned relative to the tool support unit with respect to the plane of symmetry YZ, so that each tool support unit is positioned on either the part support unit 11 or the further unit 14. This feature is advantageous in that it allows for simultaneous execution of machining operations on parts held in place by the part support unit 11 and the further unit 14. The second tool support unit is similar to the tool support unit 13 in that it has tool support units intended for supporting cutting tools and kinematically connecting to the frame 12 with the same degrees of freedom as the tool support unit 13.

[0054] More generally, the implementation forms and embodiments considered above are described as non-limiting examples, and it should be noted that other variations are possible.

[0055] In particular, the exemplary embodiments shown in Figures 1 and 2 and described above relate to a machine tool 10 supplied by guiding the parts 100 through a machining area. However, the machine tool 10 according to the present invention can be adapted to machining parts 100 in batches, for example in the form of plots, where the supply of parts 100 is performed continuously, and each part 100 to be machined originates from various semi-finished parts 100.

[0056] Furthermore, this second tool support can support a fixed or rotating tailstock.

[0057] It should be noted that the translational and rotational movements of the component support unit 11, the tool support unit 13, and any further units 14 are ensured by independent electric motors servo-controlled by a monitoring and control unit, in a manner known to those skilled in the art. [Explanation of Symbols]

[0058] 10 Numerically controlled machine tools 11 Component support unit 12 frames 13 Tool support unit 100 Semi-processed products 130 Cutting tools

Claims

1. A numerically controlled machine tool (10) for machining high-precision minute machine parts from semi-finished products in the form of rods or strips, wherein the numerically controlled machine tool (10) comprises a frame (12), a part support unit (11) intended to hold the semi-finished products and machined parts (100) from the semi-finished products in predetermined positions, and a tool support unit (13) intended to support a cutting tool (130), - The component support unit (11) is connected to the frame (12) to drive the semi-finished product and the component (100) such that the semi-finished product and the component (100) have one rotational degree of freedom and one translational degree of freedom in direction Z in the coordinate system XYZ. - The tool support unit (13) is connected to the frame (12) to drive the cutting tool (130) such that the cutting tool (130) has one translational degree of freedom in direction X and one rotational degree of freedom in direction Y. The component support unit (11) includes a component support carriage (110) connected to the frame (12) by at least one sliding body (120), the component support carriage (110) includes a component support module (112), the component support module (112) is controllable to either be in a fastened state that holds the semi-finished product and the component (100) in a predetermined position, or in a released state that allows the semi-finished product and the component (100) to move. Including a further unit (14) and a further carriage (140), The further unit (14) is connected to the frame (12) to drive the semi-worked product and the part (100) such that the semi-worked product and the part (100) have one rotational degree of freedom and one translational degree of freedom in the direction Z, the further unit (14) is configured such that the cutting tool (130) is interposed between the part support unit (11) and the further unit (14), and the further unit (14) includes the further carriage (140), The further carriage (140) is positioned opposite the part support unit (11) with respect to the tool support unit (13) and receives a pair of part support modules (141), the pair of part support modules (141) receiving a second tool support intended to fix or release the semi-worked workpiece and the part (100), or to support a cutting tool (130), The component support unit (11) includes the component support carriage (110) connected to the frame (12) by at least one sliding body (120), the component support carriage (110) includes the component support module (112), the component support module (112) is controllable to either a fastened state that holds the semi-finished product and the component (100) in a predetermined position, or a released state that allows the semi-finished product and the component (100) to move, the further carriage (140) is assembled on at least one sliding body (120) fixed to the frame (12), the sliding body (120) to which the component support carriage (110) and the further carriage (140) are connected is arranged separately from each other such that the component support carriage (110) and the further carriage (140) are at the same height position, The cutting tool (130) can be inserted into the separated portion of the sliding body (120), Each of the component support carriage (110) and the further carriage (140) is movably sealed and fixed to the frame (12) by a wiper (121) or bellows (122), wherein the wiper (121) or bellows (122) protects the numerically controlled machine tool (10) from chips and machining lubricants released from the semi-finished product, characterized in that the numerically controlled machine tool (10).

2. The numerically controlled machine tool (10) according to claim 1, wherein the component support carriage (110) has a through opening, the through opening extending in the direction Z and opening at one end of the component support module (112), and the opening is intended to receive the semi-finished product and the component (100) for supply to the machining area of ​​the numerically controlled machine tool (10).

3. The numerically controlled machine tool (10) according to claim 1, wherein the tool support unit (13) includes a first carriage (131) connected to the frame (12) by at least one sliding body (120) extending in the direction X, and a second carriage (133) connected to the first carriage (131) and including a tool support (135), the tool support (135) being able to rotate and move in the direction Y.

4. The second carriage (133) is mounted on at least one sliding body (120), the at least one sliding body (120) is fixed to the first carriage (131) and extends in the direction Y, The second carriage (133) is sealed and fixed to the first carriage (131) so as to be movable relative to the frame (12) by the wiper (121) or the bellows (122), The numerically controlled machine tool (10) according to claim 3, wherein the wiper (121) or the bellows (122) protects the numerically controlled machine tool (10) from chips and machining lubricants released from the semi-finished product.

5. The numerically controlled machine tool (10) according to claim 1, wherein the further carriage (140) has a through opening (142) extending in the direction Z and opening to one end of the pair of part support modules (141), and the through opening (142) is intended to receive the semi-finished workpiece and the part (100) in order to remove the semi-finished workpiece and the part (100) from the machining area of ​​the numerically controlled machine tool (10).

6. The numerically controlled machine tool (10) according to claim 1, wherein the part support unit (11) includes the part support carriage (110) connected to the frame (12) by at least one sliding body (120), the part support carriage (110) includes the part support module (112), the part support module (112) is controllable to either fasten the part support module (112) to hold the semi-finished product and the part (100) in a predetermined position, or release the part support module (112) to allow the semi-finished product and the part (100) to move, and the part support module (112) and the pair of part support modules (141) include positioning devices intended to guide the semi-finished product and the part (100) as they move or to hold the semi-finished product and the part (100) in a predetermined position.

7. The numerically controlled machine tool (10) according to claim 1, wherein the second tool support unit has the same function and structure as the tool support unit (13), and is symmetrically arranged with respect to the tool support unit (13) with respect to the plane of symmetry YZ with respect to the predetermined position where the semi-worked product and the part (100) are held, and the tool support unit (13) and the second tool support unit are each located on either side of the part support unit (11) and the further unit (14).

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