CNC Spindle Head for Reciprocating Wire Electrical Discharge Machining Machine

Abstract

A numerical control spindle head for a reciprocating wire electrical discharge machining tool, characterized in that: the numerical control spindle head has a Z-axis movement mechanism and a W-axis movement mechanism. The Z-axis movement mechanism includes a Z-axis carriage base, a Z-axis carriage, a Z-axis guide rail pair, an upper wire guiding and liquid guiding assembly, and a Z-axis servo drive mechanism. The W-axis movement mechanism includes a W-axis guide rail, a first W-axis slider, a second W-axis slider, a first W-axis carriage, a second W-axis carriage, a tension detector, a moving wire guide pulley, a fixed wire guide pulley, a moving wire guide pulley seat, a fixed wire guide pulley seat, and a W-axis servo drive mechanism. In this solution, the electrode wire segment that descends along the Z direction bypassing the moving wire guide pulley is the cutting working segment of the electrode wire. The W-axis movement mechanism directly acts on the cutting working segment of the electrode wire for tension detection and control of the electrode wire, and the tension control of the electrode wire in the cutting working segment is more direct and accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of wire electrical discharge machining, and particularly to a numerical control spindle head for a reciprocating wire electrical discharge machining machine tool. Background Art

[0002] Numerical control reciprocating wire electrical discharge machining machine tools (referred to as: wire electrical discharge machining machine tools) are widely used as metal cutting processing equipment in the processing of precision and complex-shaped parts in manufacturing industries such as molds, aerospace, automobiles, energy, precision instruments, medical devices, and electronic products, and play an important role in industrial production. Wire electrical discharge machining uses a continuously moving thin metal wire (referred to as the electrode wire) as the electrode to perform pulsed spark discharge on the workpiece to erode the metal and cut it into shape.

[0003] The mechanical system of a wire electrical discharge machining machine tool consists of a machine tool bed, a coordinate worktable, a wire feeding mechanism, a wire frame mechanism, a taper mechanism, a lubrication system, etc. Among them, the wire feeding mechanism refers to the mechanism used to drive the electrode wire to reciprocate, and the wire frame mechanism refers to the mechanism used to support the electrode wire. The wire frame mechanism is divided into a single-column cantilever type and a double-column gantry type. The single-column cantilever type is further divided into an upper wire arm and a lower wire arm. Generally, the lower wire arm is fixed, and the upper wire arm can move up and down (Z-axis movement). The "spindle head" in the numerical control spindle head of this application is the upper wire arm that can move up and down (Z-axis movement), and "numerical control" means that the up and down movement (Z-axis movement) of the upper wire arm can be digitally controlled through a servo motor. From a functional perspective, the numerical control spindle head of a wire electrical discharge machining machine tool is an upper wire arm mechanism used to install an upper wire guide nozzle, an upper working fluid nozzle, and an upper guide wheel. This mechanism usually has a Z-axis movement mechanism that can drive the upper wire guide nozzle, the upper working fluid nozzle, and the upper guide wheel to perform numerical control up and down movement along the Z-axis.

[0004] During the wire cutting process, on the one hand, the electrode wire is supported on the wire frame mechanism through each guide wheel, and on the other hand, it is driven by the wire feeding mechanism to perform a reciprocating cutting movement. The tension control of the cutting section of the electrode wire is very important, which not only directly affects the cutting accuracy and quality but also directly affects the cutting efficiency and the service life of the electrode wire. In the prior art, various technical solutions for constant tension control of the electrode wire are given (not exemplified here one by one). However, generally speaking, there are more or less some problems, such as inaccurate tension control, the existence of links such as guide wheels and power feeding blocks between the tension control section and the cutting working section of the electrode wire, resulting in indirect tension control and additional deviations.

[0005] In view of this, how to design a more direct and accurate tension control for the electrode wire in the cutting working section is the research topic of the present invention. Summary of the Invention

[0006] The present invention provides a numerical control spindle head for a reciprocating wire electrical discharge machining tool, aiming to solve the problems of indirect and inaccurate control of the tension of the electrode wire in the cutting working section in the prior art.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a numerical control spindle head for a reciprocating wire electrical discharge machining tool, and its innovation lies in: the numerical control spindle head has a Z-axis movement mechanism and a W-axis movement mechanism. Define the up-down direction of the machine tool in the working state as the Z direction, the left-right direction as the X direction, and the front-back direction as the Y direction. Among them, the axes of the Z-axis and the W-axis are both arranged parallel in the Z direction.

[0008] The Z-axis movement mechanism includes a Z-axis carriage base, a Z-axis carriage, a Z-axis guide rail pair, an upper wire guiding and liquid guiding assembly, and a Z-axis servo drive mechanism, where:

[0009] The Z-axis carriage base is fixed relative to the machine tool column, the Z-axis carriage is connected to the Z-axis carriage base through the Z-axis guide rail pair, and the Z-axis guide rail pair guides the Z-axis carriage to make precise movement in the Z-axis direction.

[0010] The upper wire guiding and liquid guiding assembly is positioned and installed on the Z-axis carriage.

[0011] The Z-axis servo drive mechanism is drivingly connected to the Z-axis carriage and can drive the Z-axis carriage to make a digital linear movement in the Z direction.

[0012] The W-axis movement mechanism includes a W-axis guide rail, a first W-axis slider, a second W-axis slider, a first W-axis carriage, a second W-axis carriage, a tension detector, a moving guide pulley, a fixed guide pulley, a moving guide pulley seat, a fixed guide pulley seat, and a W-axis servo drive mechanism, where:

[0013] The W-axis guide rail is fixedly installed on the Z-axis carriage base, the first W-axis slider and the second W-axis slider are both installed on the W-axis guide rail, and both the first W-axis slider and the second W-axis slider can make precise movement in the W-axis direction along the W-axis guide rail. The first W-axis slider is located above the second W-axis slider.

[0014] The first W-axis carriage is fixedly connected to the first W-axis slider, and the second W-axis carriage is fixedly connected to the second W-axis slider.

[0015] The tension detector has an upper acting end and a lower acting end. The upper acting end is fixedly connected to the first W-axis carriage, and the lower acting end is fixedly connected to the second W-axis carriage. The connection line between the upper acting end and the lower acting end is parallel to the Z direction, so that the force direction of the tension detector is the Z direction.

[0016] The moving guide wheel is rotatably connected to the moving guide wheel seat, and the moving guide wheel is positioned and connected to the second carriage of the W axis through the moving guide wheel seat. The axis of the moving guide wheel is perpendicular to the YZ plane, and the axis of the electrode wire descending along the Z direction around the moving guide wheel is parallel to the Z direction. The fixed guide wheel is rotatably connected to the fixed guide wheel seat, and the fixed guide wheel is fixedly connected to the Z-axis carriage seat through the fixed guide wheel seat. The axis of the fixed guide wheel is parallel to the axis of the moving guide wheel.

[0017] The W-axis servo drive mechanism is drivingly connected to the first carriage of the W axis and can drive the first carriage of the W axis and drive the second carriage of the W axis to perform digital linear motion in the Z direction through the tension detector.

[0018] In the working state, the electrode wire segment that descends along the Z direction around the moving guide wheel to the lower wire guide nozzle on the lower wire arm of the machine tool is the cutting working segment of the electrode wire.

[0019] In the working state, the gravity of the second slider of the W axis, the second carriage of the W axis, the moving guide wheel seat, the moving guide wheel and the tension of the electrode wire acting on the moving guide wheel act vertically downward in the Z direction on the lower acting end of the tension detector. The W-axis servo drive mechanism acts vertically upward in the Z direction on the upper acting end of the tension detector through the pulling force of the first carriage of the W axis. The machine tool control system can realize the constant tension control of the electrode wire through the servo control of driving the first carriage of the W axis and the moving guide wheel by the W-axis drive according to the electrode wire tension data measured by the tension detector, and the control of the electrode wire tension directly acts on the cutting working segment of the electrode wire.

[0020] The explanations of the relevant content in the above technical solutions are as follows:

[0021] 1. In the above solution, the upper wire guide nozzle and the working fluid nozzle in the upper wire guide and liquid injection assembly are both positioned and installed on the Z-axis carriage. Among them, the working fluid nozzle is arranged below the upper wire guide nozzle. In the present invention, the upper wire guide and liquid injection assembly is a general term for structures such as wire guiding, liquid spraying, and power feeding. Some are composed of an upper main guide wheel, a wire guide nozzle, a nozzle, and a power feeding block, some are composed of a wire guide nozzle, a nozzle, and a power feeding block, and some are composed of an upper main guide wheel, a nozzle, and a power feeding block. Only the upper wire guide nozzle and the working fluid spray are shown in the attached drawings of the embodiments of the present invention.

[0022] 2. In the above solution, the Z-axis guide rail pair is composed of a Z-axis guide rail and a Z-axis slider. Among the Z-axis guide rail and the Z-axis slider, one is fixedly installed on the Z-axis carriage seat, and the other is fixedly installed on the Z-axis carriage. The Z-axis guide rail is arranged along the Z axis, and the Z-axis slider is installed on the Z-axis guide rail and can perform precise movement in the Z-axis direction.

[0023] 3. In the above solution, the Z-axis guide rail pair is composed of a Z-axis fixed rail and a Z-axis moving rail. The Z-axis fixed rail is fixedly connected to the Z-axis carriage seat, the Z-axis moving rail is fixedly connected to the Z-axis carriage, and the Z-axis fixed rail and the Z-axis moving rail are movably matched.

[0024] 4. In the above solution, the Z-axis servo drive mechanism is composed of a synchronous pulley pair, a Z-axis lead screw nut pair, and a Z-axis servo motor. Among them, the synchronous pulley pair consists of a first pulley, a second pulley, and a synchronous belt, and the Z-axis lead screw nut pair consists of a Z-axis lead screw and a Z-axis nut.

[0025] The Z-axis servo motor is fixedly installed on the Z-axis carriage seat. The Z-axis servo motor is drivingly connected to the first pulley. The axis of the Z-axis servo motor is coaxial with the axis of the first pulley and parallel to the Z direction. The first pulley is drivingly connected to the second pulley through the synchronous belt. The axis of the first pulley is parallel to the axis of the second pulley. The second pulley is drivingly connected to the Z-axis lead screw. The Z-axis lead screw cooperates with the Z-axis nut. The axis of the second pulley, the axis of the Z-axis lead screw, and the axis of the Z-axis nut are coaxial and parallel to the Z direction. The Z-axis nut is fixedly connected to the Z-axis carriage.

[0026] 5. In the above solution, the W-axis servo drive mechanism is composed of a W-axis lead screw nut pair and a W-axis servo motor. The W-axis lead screw nut pair consists of a W-axis lead screw and a W-axis nut. The motor shaft of the W-axis servo motor is coaxially and fixedly connected to the W-axis lead screw. The W-axis servo motor is fixedly installed on the Z-axis carriage seat. The axis of the motor shaft of the W-axis servo motor is parallel to the Z direction. The W-axis nut cooperates with the W-axis lead screw. The W-axis nut is fixedly connected to the first W-axis carriage.

[0027] Due to the application of the above solution, the present invention has the following substantial features and effects compared with the prior art:

[0028] 1. The present invention ingeniously designs a W-axis motion mechanism on the Z-axis carriage and the Z-axis carriage seat, which has a compact structure, is scientific and reasonable, and meets the functional requirements of automatic wire threading of the machine tool;

[0029] 2. Through the connection structure design of the tension detector of the W-axis motion mechanism of the present invention, the online detection of the tension change of the electrode wire of the machine tool by the tension detector is realized. According to the measured electrode wire tension data, the machine tool control system can achieve constant tension control of the electrode wire through servo control of the W-axis servo motor. In particular, the tension control of the electrode wire by the W-axis motion mechanism directly acts on the cutting working section of the electrode wire, avoiding the problems that the existing tension control mechanism does not directly act on the cutting working section of the electrode wire, and there are links such as guide wheels and feeding blocks between the tension control section and the cutting working section of the electrode wire, resulting in indirect tension control and additional deviation. Therefore, the tension control of the electrode wire in the cutting working section designed by the present invention is more direct and accurate.

[0030] 3. The W-axis motion mechanism of the present invention not only better controls the tension of the electrode wire during the cutting process of the machine tool, but also can set different tension values according to the requirements of automatic wire threading during the automatic wire threading process, control the tension of the electrode wire, and can cooperate with the wire storage cylinder and wire feeding mechanism of the machine tool to complete the automatic wire winding task of the electrode wire. Brief Description of the Drawings

[0031] Attached Figure 1 is the front view of the numerical control spindle head of the embodiment of the present invention.

[0032] Attached Figure 2 is the top view of the numerical control spindle head of the embodiment of the present invention.

[0033] Attached Figure 3 is the right view of the numerical control spindle head of the embodiment of the present invention.

[0034] Attached Figure 4 is Figure 3 the A-A cross-sectional view of

[0035] Attached Figure 5 is the schematic diagram of the W-axis motion mechanism of the present invention.

[0036] In the above drawings: 1. Z-axis carriage base; 2. Z-axis carriage; 3. Z-axis servo motor; 4. upper wire guide nozzle; 5. working fluid nozzle; 6. W-axis guide rail; 7. first W-axis slider; 8. second W-axis slider; 9. first W-axis carriage; 10. second W-axis carriage; 11. tension detector; 12. moving guide pulley; 13. fixed guide pulley; 14. moving guide pulley seat; 15. fixed guide pulley seat; 16. W-axis servo motor; 17. upper acting end; 18. lower acting end; 21. electrode wire; 22. Z-axis guide rail; 23. Z-axis slider; 24. first pulley; 25. second pulley; 26. synchronous belt; 27. Z-axis lead screw; 28. Z-axis nut; 29. W-axis lead screw; 30. W-axis nut. Detailed Embodiment

[0037] The present invention will be further described below in conjunction with the drawings and embodiments:

[0038] Embodiment: A numerical control spindle head for a reciprocating wire electrical discharge machining machine tool.

[0039] As Figures 1 - 5 shown, the numerical control spindle head has a Z-axis motion mechanism and a W-axis motion mechanism. It is defined that the up-down direction of the machine tool in the working state is the Z direction, the left-right direction is the X direction, and the front-back direction is the Y direction. Among them, the axes of the Z-axis and the W-axis are both arranged parallel in the Z direction.

[0040] The Z-axis motion mechanism includes a Z-axis carriage base 1 (see Figure 1 , Figure 3 and Figure 4 ), a Z-axis carriage 2 (seeFigure 2 , Figure 3 and Figure 4 ), the Z-axis guide pair, the upper wire guide nozzle 4, and the Z-axis servo drive mechanism, where:

[0041] The Z-axis carriage base 1 is fixed relative to the machine tool column. The Z-axis carriage 2 is connected to the Z-axis carriage base 1 through the Z-axis guide pair. The Z-axis guide pair guides the Z-axis carriage 2 to make precise movement in the Z-axis direction. In this embodiment, the Z-axis guide pair is composed of a Z-axis guide rail 22 and a Z-axis slider 23 (see Figure 4 ). The Z-axis guide rail 22 is fixedly installed on the Z-axis carriage base 1, and two Z-axis sliders 23 are fixedly installed on the Z-axis carriage 2 (see Figure 4 ). The present invention is not limited to this. It is also possible to exchange and fixedly install the two Z-axis sliders 23 on the Z-axis carriage base 1, while the Z-axis guide rail 22 is fixedly installed on the Z-axis carriage 2. That is, among the Z-axis guide rail 22 and the Z-axis sliders 23, one is fixedly installed on the Z-axis carriage base 1, and the other is fixedly installed on the Z-axis carriage 2. The Z-axis guide rail 22 is arranged along the Z-axis (see Figure 4 ), and the two Z-axis sliders 23 are installed on the Z-axis guide rail 22 (see Figure 4 ), and can make precise movement in the Z-axis direction. In short, the best solution is: the Z-axis guide pair is composed of a Z-axis fixed rail and a Z-axis moving rail. The Z-axis fixed rail is fixedly connected to the Z-axis carriage base 1, the Z-axis moving rail is fixedly connected to the Z-axis carriage 2, and the Z-axis fixed rail and the Z-axis moving rail are movably matched.

[0042] The upper wire guide nozzle 4 is positioned and installed on the Z-axis carriage 2 (see Figure 1 , Figure 3 and Figure 4 ). The Z-axis motion mechanism includes a working fluid nozzle 5. The working fluid nozzle 5 is positioned and installed on the Z-axis carriage 2 and is arranged below the upper wire guide nozzle 4 (see Figure 1 , Figure 3 and Figure 4 ).

[0043] The Z-axis servo drive mechanism is positioned and installed on the Z-axis carriage base 1. The Z-axis servo drive mechanism is drivingly connected to the Z-axis carriage 2 and can drive the Z-axis carriage 2 to make a digital linear motion in the Z direction. In this embodiment, the Z-axis servo drive mechanism is composed of a synchronous pulley pair, a Z-axis lead screw nut pair, and a Z-axis servo motor 3. Among them, the synchronous pulley pair is composed of a first pulley 24, a second pulley 25, and a synchronous belt 26 (see Figure 1 and Figure 2 ), and the Z-axis lead screw nut pair is composed of a Z-axis lead screw 27 and a Z-axis nut 28 (see Figure 4 ).

[0044] The Z-axis servo motor 3 is fixedly installed on the Z-axis carriage base 1 (see Figure 1), the Z-axis servo motor 3 is drivingly connected to the first pulley 24, and the axis of the Z-axis servo motor 3 is coaxial with the axis of the first pulley 24 and parallel to the Z direction (see Figure 1 ). The first pulley 24 is drivingly connected to the second pulley 25 through a timing belt 26 (see Figure 2 ), and the axis of the first pulley 24 is parallel to the axis of the second pulley 25 (see Figure 1 ). The second pulley 25 is drivingly connected to the Z-axis lead screw 27 (see Figure 4 ), and the Z-axis lead screw 27 is engaged with the Z-axis nut 28 (see Figure 4 ). The axes of the second pulley 25, the Z-axis lead screw 27, and the Z-axis nut 28 are coaxial and parallel to the Z direction (see Figure 4 ). The Z-axis nut 28 is fixedly connected to the Z-axis carriage 2 (see Figure 4 ).

[0045] The W-axis moving mechanism includes a W-axis guide rail 6, a first W-axis slider 7, a second W-axis slider 8, a first W-axis carriage 9, a second W-axis carriage 10, a tension detector 11, a moving guide pulley 12, a fixed guide pulley 13, a moving guide pulley seat 14, a fixed guide pulley seat 15, and a W-axis servo drive mechanism (see Figure 5 ), where:

[0046] The W-axis guide rail 6 is fixedly installed on the Z-axis carriage seat 1 (see Figure 1 ), and both the first W-axis slider 7 and the second W-axis slider 8 are installed on the W-axis guide rail 6 (see Figure 5 ), and both the first W-axis slider 7 and the second W-axis slider 8 can make precise movements along the W-axis guide rail 6 in the W-axis direction (see Figure 5 ), and the first W-axis slider 7 is located above the second W-axis slider 8 (see Figure 5 ).

[0047] The first W-axis carriage 9 is fixedly connected to the first W-axis slider 7 (see Figure 5 , in Figure 1 because the first W-axis slider 7 is behind the first W-axis carriage 9 and is blocked), and the second W-axis carriage 10 is fixedly connected to the second W-axis slider 8 (see Figure 5 , in Figure 1 because the second W-axis slider 8 is behind the second W-axis carriage 10 and is blocked).

[0048] The tension detector 11 has an upper acting end 17 and a lower acting end 18 (see Figure 5 and Figure 3 ), the upper acting end 17 is fixedly connected to the first W-axis carriage 9 (see Figure 5 ), the lower acting end 18 is fixedly connected to the second W-axis carriage 10 (see Figure 5 ), and the connection line between the upper acting end 17 and the lower acting end 18 is parallel to the Z direction, so that the force direction of the tension detector 11 is the Z direction (seeFigure 5 ).

[0049] The moving guide wheel 12 is rotatably connected to the moving guide wheel seat 14, and the moving guide wheel 12 is positioned and connected to the second carriage 10 of the W-axis through the moving guide wheel seat 14 (see Figure 1 ). The axis of the moving guide wheel 12 is perpendicular to the YZ plane, and the axis of the electrode wire 21 that descends along the Z direction around the moving guide wheel 12 is parallel to the Z direction (see Figure 1 and Figure 5 ). The fixed guide wheel 13 is rotatably connected to the fixed guide wheel seat 15, and the fixed guide wheel 13 is fixedly connected to the Z-axis carriage seat 1 through the fixed guide wheel seat 15 (see Figure 1 and Figure 5 ). The axis of the fixed guide wheel 13 is parallel to the axis of the moving guide wheel 12.

[0050] The W-axis servo drive mechanism is drivingly connected to the first carriage 9 of the W-axis, and can drive the first carriage 9 of the W-axis and drive the second carriage 10 of the W-axis to perform digital linear motion in the Z direction through the tension detector 11. In this embodiment, the W-axis servo drive mechanism is composed of a W-axis lead screw nut pair and a W-axis servo motor 16 connected (see Figure 5 and Figure 3 ). The W-axis lead screw nut pair is composed of a W-axis lead screw 29 and a W-axis nut 30 (see Figure 5 ). The motor shaft of the W-axis servo motor 16 is coaxially and fixedly connected to the W-axis lead screw 29 (see Figure 5 ). The W-axis servo motor 16 is fixedly installed on the Z-axis carriage seat 1, and the axis of the motor shaft of the W-axis servo motor 16 is parallel to the Z direction (see Figure 1 ). The W-axis nut 30 is matched with the W-axis lead screw 29, and the W-axis nut 30 is fixedly connected to the first carriage 9 of the W-axis (see Figure 5 , Figure 5 In the W-axis nut 30 in, a fixed connection relationship is formed with the first carriage 9 of the W-axis through a cross bar and a longitudinal bar, but the present invention is not limited thereto, and its essence is that the W-axis nut 30 and the first carriage 9 of the W-axis are fixedly connected).

[0051] In the working state, the electrode wire segment of the electrode wire 21 that descends along the Z direction around the moving guide wheel 12 to the lower wire guide nozzle on the lower wire arm of the machine tool is the cutting working segment of the electrode wire 21 (see Figure 1 and Figure 5 ).

[0052] In the working state, the gravity of the W-axis second slider 8, the W-axis second carriage 10, the moving guide wheel seat 14, the moving guide wheel 12 and the tension of the electrode wire 21 acting on the moving guide wheel 12 act vertically downward in the Z direction on the lower acting end 18 of the tension detector 11 (see Figure 5 ). The W-axis servo drive mechanism acts vertically upward in the Z direction on the upper acting end 17 of the tension detector 11 through the pulling force of the first carriage 9 of the W-axis (seeFigure 5 ), the machine tool control system can achieve constant tension control of the electrode wire 21 by servo - controlling the W - axis drive to drive the first W - axis carriage 9 and the moving guide pulley 12 according to the tension data of the electrode wire 21 measured by the tension detector 11, and the tension control of the electrode wire 21 directly acts on the cutting working section of the electrode wire 21 (see Figure 5 ). The specific process of constant tension control of the electrode wire 21 is as follows: Refer to Figure 5 As shown, the range of the constant tension control value of the electrode wire 21 should be set in the machine tool control system in advance. During operation, the machine tool control system detects the currently measured tension value through the tension detector 11, then subtracts the gravity of the second W - axis slider 8, the second W - axis carriage 10, the moving guide pulley seat 14, and the moving guide pulley 12 from the measured tension value, and divides the result by 2 to obtain the tension of the electrode wire 21 on the cutting working section. Then, the calculated tension of the electrode wire 21 is compared with the set range of the constant tension control value. When the tension of the electrode wire 21 falls within the range of the constant tension control value, it remains unchanged; when the tension of the electrode wire 21 is greater than the upper limit value of the constant tension control, the machine tool control system starts the reverse rotation of the W - axis servo motor 16, and the W - axis nut 30 drives the first W - axis carriage 9 and the first W - axis slider 7 to descend. Due to the gravity of the second W - axis slider 8, the second W - axis carriage 10, the moving guide pulley seat 14, and the moving guide pulley 12, the second W - axis slider 8, the second W - axis carriage 10, the moving guide pulley seat 14, and the moving guide pulley 12 as a whole descend, and the tension of the electrode wire 21 decreases. Then, it is detected, calculated, and compared again until the tension of the electrode wire 21 falls within the range of the constant tension control value and stops; when the tension of the electrode wire 21 is less than the lower limit value of the constant tension control, the machine tool control system starts the forward rotation of the W - axis servo motor 16, and the W - axis nut 30 drives the first W - axis carriage 9 and the first W - axis slider 7 to rise, and drives the second W - axis slider 8, the second W - axis carriage 10, the moving guide pulley seat 14, and the moving guide pulley 12 as a whole to rise through the upper acting end 17, the tension detector 11, and the lower acting end 18. The tension of the electrode wire 21 increases, and it is detected, calculated, and compared again until the tension of the electrode wire 21 falls within the range of the constant tension control value and stops. Thus, it can be seen that by using the W - axis motion mechanism of the present invention, the machine tool control system can not only achieve constant tension control of the electrode wire 21 by servo - controlling the W - axis drive to drive the first W - axis carriage 9 and the moving guide pulley 12 according to the tension data of the electrode wire 21 measured by the tension detector 11, but also the tension control of the electrode wire 21 directly acts on the cutting working section of the electrode wire 21. Therefore, the tension control of the electrode wire on the cutting working section is more direct and more accurate.

[0053] The above - mentioned embodiments are only for explaining the technical concept and characteristics of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and shall not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A CNC spindle head for a reciprocating wire electric spark cutting machine tool, characterized in that: The CNC spindle head has a Z-axis motion mechanism and a W-axis motion mechanism. The up-down direction of the machine tool in the working state is defined as the Z direction, the left-right direction is the X direction, and the front-back direction is the Y direction. The axes of the Z-axis and the W-axis are both arranged parallel in the Z direction. The Z-axis motion mechanism comprises a Z-axis carriage seat (1), a Z-axis carriage (2), a Z-axis guide rail pair, an upper wire guide assembly and a Z-axis servo drive mechanism, wherein: The Z-axis carriage seat (1) is fixed relative to the machine tool column, and the Z-axis carriage (2) is connected to the Z-axis carriage seat (1) via a Z-axis guide pair, and the Z-axis guide pair guides the Z-axis carriage (2) to perform precise movement in the Z-axis direction; The upper wire guide and liquid guide assembly is positioned and mounted on the Z-axis carriage (2); The Z-axis servo drive mechanism is drivingly connected to the Z-axis carriage (2) and is capable of driving the Z-axis carriage (2) to perform digital linear motion in the Z direction; The W-axis motion mechanism comprises a W-axis guide rail (6), a W-axis first slider (7), a W-axis second slider (8), a W-axis first carriage (9), a W-axis second carriage (10), a tension detector (11), a movable guide wheel (12), a fixed guide wheel (13), a movable guide wheel seat (14), a fixed guide wheel seat (15) and a W-axis servo drive mechanism, wherein: The W-axis guide rail (6) is fixedly mounted on the Z-axis carriage seat (1), the W-axis first slider (7) and the W-axis second slider (8) are both mounted on the W-axis guide rail (6), and the W-axis first slider (7) and the W-axis second slider (8) are both capable of making precise movements along the W-axis guide rail (6) in the W-axis direction, and the W-axis first slider (7) is located above the W-axis second slider (8); The W-axis first carriage (9) is fixedly connected to the W-axis first slider (7), and the W-axis second carriage (10) is fixedly connected to the W-axis second slider (8); The tension detector (11) comprises an upper action end (17) and a lower action end (18), the upper action end (17) being fixedly connected to the first carriage (9) of the W axis, and the lower action end (18) being fixedly connected to the second carriage (10) of the W axis, and the line connecting the upper action end (17) and the lower action end (18) being parallel to the Z direction, so that the force direction of the tension detector (11) is the Z direction; The movable guide wheel (12) is rotatably connected to the movable guide wheel seat (14), and the movable guide wheel (12) is positionally connected to the second carriage (10) of the W axis through the movable guide wheel seat (14), the axis of the movable guide wheel (12) is perpendicular to the YZ plane, and the axis of the electrode wire (21) passing around the movable guide wheel (12) and descending in the Z direction is parallel to the Z direction; the fixed guide wheel (13) is rotatably connected to the fixed guide wheel seat (15), and the fixed guide wheel (13) is fixedly connected to the Z axis carriage seat (1) through the fixed guide wheel seat (15), and the axis of the fixed guide wheel (13) is parallel to the axis of the movable guide wheel (12); The W-axis servo drive mechanism is drivingly connected to the W-axis first carriage (9), and is capable of driving the W-axis first carriage (9) and, through the tension detector (11), driving the W-axis second carriage (10) to perform digital linear motion in the Z direction; In the working state, the electrode wire section that passes by the movable guide wheel (12) and descends along the Z direction to the lower wire guide nozzle on the lower wire arm of the machine tool is the cutting working section of the electrode wire (21); In the working state, the gravity of the W-axis second slider (8), the W-axis second carriage (10), the movable guide wheel seat (14), the movable guide wheel (12), and the tension of the electrode wire (21) acting on the movable guide wheel (12) act vertically downward on the lower action end (18) of the tension detector (11) along the Z direction, and the W-axis servo drive mechanism acts vertically upward on the upper action end (17) of the tension detector (11) along the Z direction through the pulling force of the W-axis first carriage (9). The machine tool control system can achieve constant tension control of the electrode wire (21) by servo control of the W-axis drive to drive the W-axis first carriage (9) and the movable guide wheel (12) according to the tension data of the electrode wire (21) measured by the tension detector (11), and the tension control of the electrode wire (21) directly acts on the cutting working section of the electrode wire (21).

2. The CNC spindle head according to claim 1, characterized in that: The upper wire guide nozzle (4) and the working fluid nozzle (5) of the upper wire guide and fluid guide assembly are both positioned and mounted on the Z-axis carriage (2), wherein the working fluid nozzle (5) is arranged below the upper wire guide nozzle (4).

3. The CNC spindle head according to claim 1, characterized in that: The Z-axis guide rail pair is composed of a Z-axis guide rail (22) and a Z-axis slider (23). One of the Z-axis guide rail (22) and the Z-axis slider (23) is fixedly mounted on the Z-axis carriage seat (1), and the other is fixedly mounted on the Z-axis carriage (2). The Z-axis guide rail (22) is arranged along the Z-axis. The Z-axis slider (23) is mounted on the Z-axis guide rail (22) and can be precisely moved in the Z-axis direction.

4. The CNC spindle head according to claim 1, characterized in that: The Z-axis guide rail pair is composed of a Z-axis fixed rail and a Z-axis movable rail. The Z-axis fixed rail is fixedly connected to the Z-axis carriage seat (1), the Z-axis movable rail is fixedly connected to the Z-axis carriage (2), and the Z-axis fixed rail and the Z-axis movable rail are movably matched.

5. The CNC spindle head according to claim 1, characterized in that: The Z-axis servo drive mechanism is composed of a synchronous pulley pair, a Z-axis lead screw nut pair and a Z-axis servo motor (3), wherein the synchronous pulley pair is composed of a first pulley (24), a second pulley (25) and a synchronous belt (26), and the Z-axis lead screw nut pair is composed of a Z-axis lead screw (27) and a Z-axis nut (28); The Z-axis servo motor (3) is fixedly mounted on the Z-axis carriage seat (1); the Z-axis servo motor (3) is connected to the first pulley (24) in a transmission connection; the axis of the Z-axis servo motor (3) is coaxial with the axis of the first pulley (24) and parallel to the Z direction; the first pulley (24) is connected to the second pulley (25) in a transmission connection via a synchronous belt (26); the axis of the first pulley (24) is parallel to the axis of the second pulley (25); the second pulley (25) is connected to the Z-axis lead screw (27); the Z-axis lead screw (27) cooperates with the Z-axis nut (28); the axis of the second pulley (25), the axis of the Z-axis lead screw (27) and the axis of the Z-axis nut (28) are coaxial and parallel to the Z direction; the Z-axis nut (28) is fixedly connected to the Z-axis carriage (2).

6. The CNC spindle head according to claim 1, characterized in that: The W-axis servo drive mechanism is composed of a W-axis lead screw nut pair and a W-axis servo motor (16) connected together; the W-axis lead screw nut pair is composed of a W-axis lead screw (29) and a W-axis nut (30); the motor shaft of the W-axis servo motor (16) is coaxially fixedly connected to the W-axis lead screw (29); the W-axis servo motor (16) is fixedly mounted on the Z-axis carriage seat (1); the motor shaft axis of the W-axis servo motor (16) is parallel to the Z direction; the W-axis nut (30) cooperates with the W-axis lead screw (29); and the W-axis nut (30) is fixedly connected to the W-axis first carriage (9).

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