Three-axis numerical control spindle head for automatic wire threading CNC wire cutting machine

Abstract

A three-axis numerical control spindle head for an automatic wire threading CNC wire electrical discharge machining machine, characterized in that: it has Z-axis, W1-axis and W2-axis motion mechanisms. The Z-axis motion mechanism includes a Z-axis carriage base, a Z-axis carriage, a Z-axis guide rail pair, a wire guide tube positioning mechanism and a Z-axis servo drive mechanism; the W1-axis motion mechanism includes a W1-axis carriage, a W1-axis guide rail pair, a wire guide tube, a wire electrode feeding mechanism and a W1-axis servo drive mechanism; the W2-axis motion mechanism includes a W2-axis guide rail, a first W2-axis slider, a second W2-axis slider, a first W2-axis carriage, a second W2-axis carriage, a tension detector, a moving wire guide pulley, a fixed wire guide pulley and a W2-axis servo drive mechanism. The wire electrode segment that descends along the Z direction bypassing the moving wire guide pulley in this solution is the cutting working segment of the wire electrode. The W2-axis motion mechanism directly controls the tension of the wire electrode on the cutting working segment of the wire electrode, and the tension control of the wire electrode in the cutting working segment is more direct and more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of wire electrical discharge machining, and particularly relates to a three-axis numerical control spindle head for an automatic wire threading numerically controlled reciprocating wire electrical discharge machining machine tool. Background Art

[0002] Numerical control reciprocating wire electrical discharge machining machine tools (hereinafter 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 an electrode wire) as an electrode to perform pulsed spark discharge on the workpiece to erode metal and cut 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 perform reciprocating motion, 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 be lifted and moved (Z-axis movement). The "spindle head" in the numerical control spindle head of this application is the upper wire arm that can be lifted and moved (Z-axis movement), and "numerical control" means that the lifting and 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 wire guide pulley. This mechanism usually has a Z-axis movement mechanism, which can drive the upper wire guide nozzle, the upper working fluid nozzle, and the upper wire guide pulley to perform numerically controlled lifting and movement along the Z-axis.

[0004] Wire threading is required both before and during wire electrical discharge machining. Currently, the vast majority of wire electrical discharge machining machine tools can only use manual wire threading. Manual wire threading is highly specialized, requires professional personnel to operate, and has a complex process, high requirements, a large workload, and low efficiency. For this reason, in recent years, technicians in this field have been working hard to research and develop fully automatic wire threading devices and methods applicable to wire electrical discharge machining machine tools. Fully automatic wire threading is a complex and delicate system project in the technical field of wire electrical discharge machining, with high process requirements, many difficulties, and great technical challenges. It has long been a technical problem in this field. Among them, how the spindle head of a wire electrical discharge machining machine tool meets the control requirements of the relevant automatic wire threading mechanism for movement in the Z-axis direction during automatic wire threading is one of the technical difficulties that need to be overcome.

[0005] The existing reciprocating wire EDM machine tool is only equipped with a Z-axis, which can drive the upper wire guiding mechanism to move in the Z-axis direction during the wire threading process, but it cannot meet the control requirements of the machine tool's automatic wire threading for the relevant automatic wire threading mechanism's movement in the Z-axis direction. To solve this technical problem, the present invention designs a three-axis numerically controlled spindle head for an automatic wire threading reciprocating wire EDM machine tool. Summary of the Invention

[0006] The present invention provides a three-axis numerically controlled spindle head for an automatic wire threading CNC EDM machine tool, aiming to solve the problem that the existing spindle head movement mechanism cannot meet the control requirements of the machine tool's automatic wire threading for the relevant automatic wire threading mechanism's movement in the Z-axis direction.

[0007] To achieve the above object, the technical solution adopted by the present invention is: a three-axis numerically controlled spindle head for an automatic wire threading CNC EDM machine tool, which is innovative in that: the three-axis numerically controlled spindle head has a Z-axis movement mechanism, a W1-axis movement mechanism, and a W2-axis movement mechanism. The up and down direction of the machine tool in the working state is defined as the Z direction. Among them, the axes of the Z-axis, W1-axis, and W2-axis are all parallelly arranged 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, a wire guide tube positioning mechanism, 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 wire guide tube positioning mechanism is positioned and installed on the Z-axis carriage.

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

[0012] The W1-axis movement mechanism includes a W1-axis carriage, a W1-axis guide rail pair, a wire guide tube, an electrode wire feeding mechanism, and a W1-axis servo drive mechanism, where:

[0013] The W1-axis carriage is connected to the Z-axis carriage through the W1-axis guide rail pair, and the W1-axis guide rail pair guides the W1-axis carriage to make precise movement in the W1-axis direction.

[0014] The electrode wire feeding mechanism is positioned and installed on the W1-axis carriage, the wire guide tube is fixedly installed on the electrode wire feeding mechanism, the axis of the wire guide tube is parallel to the Z direction in the assembled state, the electrode wire feeding mechanism is used to digitally feed or withdraw the electrode wire into or out of the wire guide tube, and the wire guide tube positioning mechanism is used to position the lower part of the wire guide tube.

[0015] The W1-axis servo drive mechanism is positioned and installed on the Z-axis carriage. The W1-axis servo drive mechanism is drivingly connected to the W1-axis carriage and can drive the W1-axis carriage to make a digital linear motion in the Z direction between the designed strokes on the Z-axis carriage.

[0016] The W2-axis motion mechanism includes a W2-axis guide rail, a first W2-axis slider, a second W2-axis slider, a first W2-axis carriage, a second W2-axis carriage, a tension detector, a moving guide wheel, a fixed guide wheel, a moving guide wheel seat, a fixed guide wheel seat, and a W2-axis servo drive mechanism, where:

[0017] The W2-axis guide rail is fixedly installed on the Z-axis carriage seat. Both the first W2-axis slider and the second W2-axis slider are installed on the W2-axis guide rail, and both the first W2-axis slider and the second W2-axis slider can make precise movements in the W2-axis direction along the W2-axis guide rail. The first W2-axis slider is located above the second W2-axis slider.

[0018] The first W2-axis carriage is fixedly connected to the first W2-axis slider, and the second W2-axis carriage is fixedly connected to the second W2-axis slider.

[0019] The tension detector has an upper acting end and a lower acting end. The upper acting end is fixedly connected to the first W2-axis carriage, and the lower acting end is fixedly connected to the second W2-axis carriage. The line connecting the upper acting end and the lower acting end is parallel to the Z direction, so that the force application direction of the tension detector is the Z direction.

[0020] 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 W2-axis carriage through the moving guide wheel seat. The axis of the moving guide wheel is perpendicular to the Z direction. The axis of the electrode wire descending along the Z direction around the moving guide wheel is coaxial with the wire guiding hole axis of the wire guiding tube and 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 relative to the fixed guide wheel seat. The axis of the fixed guide wheel is parallel to the axis of the moving guide wheel.

[0021] The W2-axis servo drive mechanism is positioned and installed on the Z-axis carriage seat. The W2-axis servo drive mechanism is drivingly connected to the first W2-axis carriage and can drive the first W2-axis carriage and drive the second W2-axis carriage to make a digital linear motion in the Z direction through the tension detector. The motion range of the first W2-axis carriage is between the highest position of the Z-direction motion of the W1-axis carriage and the upper limit position of the first W2-axis carriage.

[0022] In the working state, the electrode wire segment that descends along the Z direction around the moving guide wheel, passes through the wire guiding hole of the wire guiding tube, and reaches the wire guiding nozzle on the lower wire arm of the machine tool is the cutting working segment of the electrode wire.

[0023] In the working state, the gravity of the second slider of the W2 axis, the second carriage of the W2 axis, the moving guide wheel seat, and the moving guide wheel, as well as the wire electrode tension acting on the moving guide wheel, act vertically downward in the Z direction on the lower acting end of the tension detector. The W2 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 W2 axis. The machine tool control system can achieve constant tension control of the wire electrode through servo control of the W2 axis drive to drive the first carriage of the W2 axis and the moving guide wheel according to the wire electrode tension data measured by the tension detector, and the control of the wire electrode tension directly acts on the cutting working section of the wire electrode.

[0024] The relevant content in the above technical solution is explained as follows:

[0025] 1. In the above solution, the wire guide tube is a slender tubular structure, with an axially penetrating wire guide hole provided in the middle. The wire guide hole is used to guide automatic wire threading, and the axis of the wire guide hole is parallel to the Z direction. The statement that the wire guide tube is a slender tubular structure means that the wire guide tube is a tubular structure with a small diameter and a large length, with its diameter in the range of Φ1 - Φ20 mm, its length in the range of 100 - 1000 mm, and the length-diameter ratio in the range of 5:1 - 500:1. Preferably, the diameter is in the range of Φ2 - Φ8 mm, the length is in the range of 100 - 1000 mm, and the length-diameter ratio is in the range of 10:1 - 300:1.

[0026] The wire electrode feeding mechanism is located above the wire guide tube and is arranged directly opposite the wire threading inlet of the wire guide tube.

[0027] The wire guide tube positioning mechanism is a positioning and clamping structure for the lower part of the wire guide tube. The positioning and clamping structure is provided with a positioning hole, which is used to position the outer cylindrical surface of the lower part of the wire guide tube. The positioning central axis of the positioning hole for the outer cylindrical surface of the lower part of the wire guide tube is coaxial with the axis of the wire guide hole of the wire guide tube. The positioning and clamping structure can automatically lock or release the lower part of the wire guide tube in the positioning hole under the control of the machine tool control system. In the released state, the W1 axis servo drive mechanism can drive the wire guide tube to move up and down along the axis direction in the positioning hole through the W1 axis carriage.

[0028] 2. In the above solution, the Z-axis guide 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 make precise movement in the Z-axis direction.

[0029] 3. In the above solution, 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 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 in moving cooperation.

[0030] 4. In the above scheme, the Z-axis servo drive mechanism is composed of a synchronous pulley pair, a Z-axis screw nut pair and a Z-axis servo motor, wherein the synchronous pulley pair is composed of a small pulley, a large pulley and a synchronous belt, and the Z-axis screw nut pair is composed of a Z-axis screw and a Z-axis nut.

[0031] The Z-axis servo motor is fixedly mounted on the Z-axis carriage seat, and the Z-axis servo motor is connected to the small pulley in a transmission manner, and the axis of the Z-axis servo motor is coaxial with the axis of the small pulley and parallel to the Z direction. The small pulley is connected to the large pulley in a transmission manner through a synchronous belt, and the axis of the small pulley is parallel to the axis of the large pulley. The large pulley is connected to the Z-axis lead screw in a transmission manner, and the Z-axis lead screw cooperates with the Z-axis nut, and the axis of the large 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.

[0032] 5. In the above scheme, the W1 axis guide pair is composed of a double cylindrical guide rod and a linear guide sleeve combination, wherein the double cylindrical guide rod and linear guide sleeve combination is composed of two cylindrical guide rods and four linear bearings.

[0033] Two bearing seats are set for the four linear bearings, two linear bearings are fixedly installed in parallel on one bearing seat, and the other two linear bearings are fixedly installed in parallel on the other bearing seat. The two bearing seats are arranged at a distance up and down in the Z direction and fixedly installed on the Z-axis slide. The axes of the four linear bearings on the two bearing seats are coaxial in pairs in the up and down directions, and are parallel in pairs in the left and right directions and parallel to the Z direction, thereby forming two groups of coaxial linear bearings.

[0034] A positioning connection block is set for the two cylindrical guide rods, and the two cylindrical guide rods are correspondingly inserted into the inner holes of the two sets of coaxial linear bearings. The upper ends of the two cylindrical guide rods are fixedly connected by the positioning connection block, and the center distance between the two cylindrical guide rods is maintained. The lower ends of the two cylindrical guide rods are positioned and fixedly connected to the W1-axis slide plate.

[0035] 5. In the above scheme, the W1-axis servo drive mechanism is composed of a W1-axis lead screw nut pair and a W1-axis servo motor, the W1-axis lead screw nut pair is composed of a W1-axis lead screw and a W1-axis nut, the W1-axis servo motor is fixedly mounted on the Z-axis carriage through a W1-axis motor seat, the motor shaft of the W1-axis servo motor is coaxially fixedly connected with the W1-axis lead screw, the motor shaft axis of the W1-axis servo motor is parallel to the Z direction, the W1-axis nut cooperates with the W1-axis lead screw, and the W1-axis nut is fixedly connected relative to the W1-axis carriage. In order to simplify the structure and reduce costs, the W1-axis lead screw nut pair and the W1-axis servo motor can use a servo motor with a lead screw nut pair.

[0036] 6. In the above solution, the W2-axis servo drive mechanism is composed of a W2-axis lead screw nut pair and a W2-axis servo motor connected. The W2-axis lead screw nut pair consists of a W2-axis lead screw and a W2-axis nut. The motor shaft of the W2-axis servo motor is coaxially and fixedly connected to the W2-axis lead screw. The axis of the motor shaft of the W2-axis servo motor is parallel to the Z direction. The W2-axis nut is engaged with the W2-axis lead screw, and the W2-axis nut is fixedly connected to the W2-axis first carriage.

[0037] Due to the application of the above solution, the present invention has the following substantial features and effects compared with the prior art:

[0038] 1. The present invention ingeniously designs a W1-axis motion mechanism and a W2-axis motion mechanism on the Z-axis carriage and the Z-axis carriage seat. Its structure is compact, scientific and reasonable, meeting the functional requirements of the automatic wire threading of the machine tool.

[0039] 2. An electrode wire feeding mechanism (wire feeding mechanism) and a wire guide tube of the automatic wire threading system of the machine tool can be installed on the W1-axis carriage of the present invention. Driven by the W1-axis servo motor, the electrode wire feeding mechanism and the wire guide tube can be driven to perform a digital linear motion in the Z direction, meeting the motion control requirements of the electrode wire feeding mechanism and the wire guide tube in the Z direction during automatic wire threading.

[0040] 3. Through the design of the connection structure of the tension detector, the W2-axis motion mechanism of the present invention realizes the online detection of the tension change of the electrode wire of the machine tool by the tension detector. According to the measured electrode wire tension data, the machine tool control system can realize the constant tension control of the electrode wire through the servo control of the W2-axis servo motor. In particular, the W2-axis motion mechanism directly acts on the cutting working section of the electrode wire for the tension control 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 power 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 design of the present invention for the tension control of the electrode wire in the cutting working section is more direct and accurate.

[0041] 4. The W2-axis motion mechanism of the present invention can not only better control 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 to control the tension of the electrode wire, and can cooperate with the wire storage cylinder and the wire feeding mechanism of the machine tool to complete the automatic wire winding task of the electrode wire.

[0042] 5. The Z-axis carriage of the present invention can drive the wire guide tube positioning mechanism installed at its lower end to perform a digital linear motion in the Z direction, and can also drive the W1-axis to move synchronously in the Z direction, meeting both the normal cutting requirements of the machine tool and the automatic wire threading requirements of the machine tool. Description of the Drawings

[0043] Appendix Figure 1This is the front view of the three-axis CNC spindle head according to the embodiment of the present invention.

[0044] Appendix Figure 2 is Figure 1 a partial enlarged view.

[0045] Appendix Figure 3 This is the top view of the three-axis CNC spindle head according to the embodiment of the present invention.

[0046] Appendix Figure 4 This is the right view of the three-axis CNC spindle head according to the embodiment of the present invention.

[0047] Appendix Figure 5 is Figure 4 a partial enlarged view.

[0048] Appendix Figure 6 is Figure 4 the A-A sectional view of.

[0049] Appendix Figure 7 is Figure 6 a partial enlarged view.

[0050] Appendix Figure 8 This is the schematic diagram of the W2-axis movement mechanism of the present invention.

[0051] In the above figures: 1. Z-axis carriage base; 2. Z-axis carriage; 3. Z-axis servo motor; 4. W1-axis carriage; 5. W1-axis servo motor; 6. W2-axis guide rail; 7. First slider of W2-axis; 8. Second slider of W2-axis; 9. First carriage of W2-axis; 10. Second carriage of W2-axis; 11. Tension detector; 12. Movable guide pulley; 13. Fixed guide pulley; 14. Movable guide pulley seat; 15. Fixed guide pulley seat; 16. W2-axis servo motor; 17. Upper acting end; 18. Lower acting end; 19. Wire guide tube; 20. Electrode wire feeding mechanism; 21. Electrode wire; 22. Z-axis guide rail; 23. Z-axis slider; 24. Small pulley; 25. Large pulley; 26. Synchronous belt; 27. Z-axis lead screw; 28. Z-axis nut; 29. Cylindrical guide rod; 30. Linear bearing; 31. Bearing seat; 32. Positioning connection block; 33. W1-axis lead screw; 34. W1-axis nut; 35. W1-axis motor seat; 36. W2-axis lead screw; 37. W2-axis nut; 38. Wire guide tube positioning mechanism. Detailed implementation manners

[0052] The present invention will be further described below in conjunction with the drawings and embodiments:

[0053] Embodiment: A three-axis CNC spindle head for an automatic wire threading CNC wire cut electrical discharge machine.

[0054] As Figures 1-8As shown in the figure, the three-axis numerical control spindle head has a Z-axis movement mechanism, a W1-axis movement mechanism, and a W2-axis movement mechanism. It is defined that the up and down direction of the machine tool in the working state is the Z direction. Among them, the axes of the Z-axis, W1-axis, and W2-axis are all parallelly arranged in the Z direction.

[0055] The Z-axis movement mechanism includes a Z-axis carriage base 1 (see Figure 2 and Figure 7 ), a Z-axis carriage 2 (see Figure 5 and Figure 7 ), a Z-axis guide pair, a wire guide tube positioning mechanism 38 (see Figure 2 , Figure 5 and Figure 7 ), and a Z-axis servo drive mechanism, where:

[0056] 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 a Z-axis guide pair. The Z-axis guide pair guides the Z-axis carriage 2 to make precise movements in the Z 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 7 ). 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 7 ). The present invention is not limited to this, and it is also possible to exchange and fixedly install the Z-axis slider 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 slider 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 7 ), and two Z-axis sliders 23 are installed on the Z-axis guide rail 22 (see Figure 7 ), and can make precise movements in the Z 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.

[0057] 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 small pulley 24, a large pulley 25, and a synchronous belt 26 (see Figure 2 and Figure 3 ), 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 7 ).

[0058] The Z-axis servo motor 3 is fixedly installed on the Z-axis carriage base 1 (seeFigure 2 ), the Z-axis servo motor 3 is drivingly connected to the small pulley 24, and the axis of the Z-axis servo motor 3 is coaxial with the axis of the small pulley 24 and parallel to the Z direction (see Figure 2 ). The small pulley 24 is drivingly connected to the large pulley 25 through a synchronous belt 26 (see Figure 3 ), and the axis of the small pulley 24 is parallel to the axis of the large pulley 25 (see Figure 2 ). The large pulley 25 is drivingly connected to the Z-axis lead screw 27 (see Figure 7 ), and the Z-axis lead screw 27 is engaged with the Z-axis nut 28 (see Figure 7 ). The axis of the large 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 (see Figure 7 ). The Z-axis nut 28 is fixedly connected to the Z-axis carriage 2 (see Figure 7 ).

[0059] The W1-axis moving mechanism includes a W1-axis carriage 4 (see Figure 5 ), a W1-axis guide pair, a wire guide tube 19 (see Figure 1 and Figure 2 ), a wire electrode feeding mechanism 20 (see Figure 2 , Figure 3 and Figure 5 ), and a W1-axis servo drive mechanism, wherein:

[0060] The W1-axis carriage 4 is connected to the Z-axis carriage 2 through a W1-axis guide pair, and the W1-axis guide pair guides the W1-axis carriage 4 to make precise movements in the W1-axis direction. In this embodiment, the W1-axis guide pair is composed of a combination of double cylindrical guide rods and linear guide sleeves. Among them, the combination of double cylindrical guide rods and linear guide sleeves is composed of two cylindrical guide rods 29 and four linear bearings 30 (see Figure 5 ).

[0061] Two bearing seats 31 are provided for the four linear bearings 30 (see Figure 5 ). Two linear bearings 30 are fixedly installed side by side on one bearing seat 31 (see Figure 5 ), and the other two linear bearings 30 are fixedly installed side by side on another bearing seat 31 (see Figure 5 ). The two bearing seats 31 are arranged at a certain distance from each other in the up and down directions in the Z direction and are fixedly installed on the Z-axis carriage 2 (see Figure 5 ). The axes of the four linear bearings 30 on the two bearing seats 31 are coaxial in pairs in the up and down directions, and are side by side in pairs and parallel to the Z direction in the left and right directions, thereby forming two sets of coaxial linear bearings 30 (see Figure 5 ).

[0062] One positioning connection block 32 is provided for the two cylindrical guide rods 29 (see Figure 5 ), and the two cylindrical guide rods 29 are correspondingly inserted into the inner holes of the two sets of coaxial linear bearings 30 (seeFigure 5 ), the upper ends of the two cylindrical guide rods 29 are fixedly connected through a positioning connection block 32, and the center distance between the two cylindrical guide rods 29 is maintained (see Figure 5 ), and the lower ends of the two cylindrical guide rods 29 are fixedly and positioningly connected to the W1-axis carriage 4.

[0063] The W1-axis servo drive mechanism is positioned and installed on the Z-axis carriage 2. The W1-axis servo drive mechanism is drivingly connected to the W1-axis carriage 4 and can drive the W1-axis carriage 4 to perform a digital linear motion in the Z direction between the designed strokes on the Z-axis carriage 2. In this embodiment, the W1-axis servo drive mechanism is composed of a W1-axis lead screw nut pair and a W1-axis servo motor 5 connected. The W1-axis lead screw nut pair is composed of a W1-axis lead screw 33 and a W1-axis nut 34 (see Figure 2 , Figure 5 and Figure 7 ), the W1-axis servo motor 5 is fixedly installed on the Z-axis carriage 2 through a W1-axis motor base 35 (see Figure 5 ), the motor shaft of the W1-axis servo motor 5 is coaxially and fixedly connected to the W1-axis lead screw 33 (see Figure 5 and Figure 7 ), the axis of the motor shaft of the W1-axis servo motor 5 is parallel to the Z direction (see Figure 7 ), the W1-axis nut 34 is engaged with the W1-axis lead screw 33 (see Figure 5 and Figure 7 ), and the W1-axis nut 34 is fixedly connected relative to the W1-axis carriage 4. That is, it can be directly seen from Figure 5 that the W1-axis nut 34 is fixedly connected to the positioning connection block 32, the positioning connection block 32 is fixedly connected to the upper ends of the two cylindrical guide rods 29, and the lower ends of the two cylindrical guide rods 29 are fixedly connected to the W1-axis carriage 4. In this embodiment, the W1-axis lead screw nut pair and the W1-axis servo motor 5 adopt a servo motor with a built-in lead screw nut pair, which has a simpler structure and lower cost.

[0064] In the present invention, the wire guide tube 19 is a slender tubular structure (see Figure 1 and Figure 4 ), and an axially penetrating wire guide hole is provided in the middle thereof. The wire guide hole is used to guide automatic wire threading, and the axis of the wire guide hole is parallel to the Z direction. The fact that the wire guide tube is a slender tubular structure means that the wire guide tube is a tubular structure with a small diameter and a large length, and its diameter ranges from Φ1 - Φ20 mm, the length ranges from 100 - 1000 mm, and the length-to-diameter ratio ranges from 5:1 - 500:1. Preferably: the diameter ranges from Φ2 - Φ8 mm, the length ranges from 100 - 1000 mm, and the length-to-diameter ratio ranges from 10:1 - 300:1.

[0065] The wire electrode feeding mechanism 20 is positioned and installed on the W1-axis carriage 4 (see Figure 5), the guide wire tube 19 is fixedly installed on the electrode wire feeding mechanism 20 (see Figure 5 ), the electrode wire feeding mechanism 20 is located above the guide wire tube 19 and is arranged opposite to the wire threading inlet of the guide wire tube 19 (see Figure 5 ), in the assembled state, the axis of the guide wire tube 19 is parallel to the Z direction (see Figure 5 ), and the electrode wire feeding mechanism 20 is used to digitally feed or withdraw the electrode wire 21 into or out of the guide wire tube 19. In the present invention, the specific structure of the electrode wire feeding mechanism 20 (also known as the "wire feeding mechanism") can adopt the prior art, such as a roller wire feeding mechanism, etc.

[0066] The guide wire tube positioning mechanism 38 is fixedly installed on the Z-axis carriage 2 (see Figure 7 ). The guide wire tube positioning mechanism 38 is used to position the lower part of the guide wire tube 19 (see Figure 5 ), the guide wire tube positioning mechanism 38 is a positioning and clamping structure for the lower part of the guide wire tube 19, and a positioning hole (not shown in the figure) is provided on the positioning and clamping structure. The positioning hole is used to position the outer cylindrical surface of the lower part of the guide wire tube 19. The positioning central axis of the positioning hole for the outer cylindrical surface of the lower part of the guide wire tube 19 is coaxial with the axis of the wire guiding hole of the guide wire tube 19. The positioning and clamping structure can automatically lock or release the lower part of the guide wire tube 19 in the positioning hole under the control of the machine tool control system. In the released state, the W1-axis servo drive mechanism can drive the guide wire tube 19 to move up and down along the axis direction in the positioning hole (see Figure 5 ).

[0067] The W2-axis movement mechanism includes a W2-axis guide rail 6, a first W2-axis slider 7, a second W2-axis slider 8, a first W2-axis carriage 9, a second W2-axis carriage 10, a tension detector 11, a moving guide wheel 12, a fixed guide wheel 13, a moving guide wheel seat 14, a fixed guide wheel seat 15, and a W2-axis servo drive mechanism (see Figure 8 ), where:

[0068] The W2-axis guide rail 6 is fixedly installed on the Z-axis carriage seat 1 (see Figure 2 ), the first W2-axis slider 7 and the second W2-axis slider 8 are both installed on the W2-axis guide rail 6 (see Figure 8 ), and both the first W2-axis slider 7 and the second W2-axis slider 8 can make precise movements along the W2-axis guide rail 6 in the W2-axis direction (see Figure 8 ), and the first W2-axis slider 7 is located above the second W2-axis slider 8 (see Figure 8 ).

[0069] The first W2-axis carriage 9 is fixedly connected to the first W2-axis slider 7 (see Figure 8 , in Figure 2 because the first W2-axis slider 7 is behind the first W2-axis carriage 9 and is blocked), the second W2-axis carriage 10 is fixedly connected to the second W2-axis slider 8 (seeFigure 8 , in Figure 2 (because the second slider 8 of the W2 axis is behind the second carriage 10 of the W2 axis and is blocked).

[0070] The tension detector 11 has an upper acting end 17 and a lower acting end 18 (see Figure 8 and Figure 5 ), the upper acting end 17 is fixedly connected to the first carriage 9 of the W2 axis (see Figure 5 ), the lower acting end 18 is fixedly connected to the second carriage 10 of the W2 axis (see Figure 8 ), 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 application direction of the tension detector 11 is the Z direction (see Figure 8 ).

[0071] The movable guide pulley 12 is rotatably connected to the movable guide pulley seat 14, and the movable guide pulley 12 is positioned and connected to the second carriage 10 of the W2 axis through the movable guide pulley seat 14 (see Figure 2 ), the axis of the movable guide pulley 12 is perpendicular to the Z direction, the axis of the electrode wire 21 descending along the Z direction bypassing the movable guide pulley 12 is coaxial with the wire guiding hole axis of the wire guiding tube 19, and is parallel to the Z direction (see Figure 2 and Figure 8 ). The fixed guide pulley 13 is rotatably connected to the fixed guide pulley seat 15, and the fixed guide pulley 13 is fixedly connected to the Z-axis carriage seat 1 relative to the Z-axis (see Figure 2 and Figure 8 ), the axis of the fixed guide pulley 13 is parallel to the axis of the movable guide pulley 12.

[0072] The W2-axis servo drive mechanism is positioned and installed on the Z-axis carriage seat 1, the W2-axis servo drive mechanism is drivingly connected to the first carriage 9 of the W2 axis, and can drive the first carriage 9 of the W2 axis and drive the second carriage 10 of the W2 axis to perform digital linear motion in the Z direction through the tension detector 11. The motion range of the first carriage 9 of the W2 axis is between the highest position of the motion of the carriage 4 of the W1 axis in the Z direction and the upper limit position of the first carriage 9 of the W2 axis. In this embodiment, the W2-axis servo drive mechanism is composed of a W2-axis lead screw nut pair and a W2-axis servo motor 16 connected. The W2-axis lead screw nut pair is composed of a W2-axis lead screw 36 and a W2-axis nut 37 (see Figure 2 ), the motor shaft of the W2-axis servo motor 16 is coaxially and fixedly connected to the W2-axis lead screw 36 (see Figure 2 ), the axis of the motor shaft of the W2-axis servo motor 16 is parallel to the Z direction, the W2-axis nut 37 is matched with the W2-axis lead screw 36, and the W2-axis nut 37 is fixedly connected to the first carriage 9 of the W2 axis (see Figure 8 , Figure 8The W2-axis nut 37 is fixedly connected to the first W2-axis carriage 9 through a cross bar and a longitudinal bar. However, the present invention is not limited thereto. Its essence is that the W2-axis nut 37 and the first W2-axis carriage 9 are fixedly connected.

[0073] In the working state, the electrode wire segment that bypasses the moving guide wheel 12 and descends along the Z direction and passes through the wire guide hole of the wire guide tube 19 to the wire nozzle on the lower wire arm of the machine tool is the cutting working segment of the electrode wire 21 (see Figure 2 and Figure 8 ).

[0074] In the working state, the gravity of the second W2-axis slider 8, the second W2-axis 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 along the Z direction on the lower acting end 18 of the tension detector 11 (see Figure 8 ). The W2-axis servo drive mechanism acts vertically upward along the Z direction on the upper acting end 17 of the tension detector 11 through the pulling force of the first W2-axis carriage 9 (see Figure 8 ). The machine tool control system can realize the constant tension control of the electrode wire 21 through the servo control of driving the first W2-axis carriage 9 and the moving guide wheel 12 by the W2-axis 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 segment of the electrode wire 21 (see Figure 8 ). The specific process of the constant tension control of the electrode wire 21 is: Refer to Figure 8As shown in the figure, the constant tension control value range 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 slider 8 of the W2 axis, the second carriage 10 of the W2 axis, the moving guide wheel seat 14, and the moving guide wheel 12 from the measured tension value, and divides the result by 2 to obtain the tension of the electrode wire 21 in the cutting working section. Then, the calculated tension of the electrode wire 21 is compared with the set constant tension control value range. When the tension of the electrode wire 21 falls within the constant tension control value range, 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 servo motor 16 of the W2 axis. The nut 37 of the W2 axis drives the first carriage 9 of the W2 axis and the first slider 7 of the W2 axis to descend. Due to the gravity of the second slider 8 of the W2 axis, the second carriage 10 of the W2 axis, the moving guide wheel seat 14, and the moving guide wheel 12, the second slider 8 of the W2 axis, the second carriage 10 of the W2 axis, the moving guide wheel seat 14, and the moving guide wheel 12 as a whole descend, and the tension of the electrode wire 21 decreases. Detection, calculation, and comparison are performed again until the tension of the electrode wire 21 falls within the constant tension control value range and then 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 servo motor 16 of the W2 axis. The nut 37 of the W2 axis drives the first carriage 9 of the W2 axis and the first slider 7 of the W2 axis to ascend, and drives the second slider 8 of the W2 axis, the second carriage 10 of the W2 axis, the moving guide wheel seat 14, and the moving guide wheel 12 as a whole to ascend through the upper acting end 17, the tension detector 11, and the lower acting end 18. The tension of the electrode wire 21 increases. Detection, calculation, and comparison are performed again until the tension of the electrode wire 21 falls within the constant tension control value range and then stops. Thus, it can be seen that by using the W2 axis movement mechanism of the present invention, the machine tool control system can not only achieve the constant tension control of the electrode wire 21 by servo control of driving the first carriage 9 of the W2 axis and the moving guide wheel 12 through the W2 axis according to the tension data of the electrode wire 21 measured by the tension detector 11, but also directly act on the cutting working section of the electrode wire 21 for the tension control of the electrode wire 21. Therefore, the tension control of the electrode wire in the cutting working section is more direct and accurate.

[0075] The above embodiments are only used to illustrate the technical concept and features of the present invention, and their purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A three-axis CNC spindle head for an automatic wire threading CNC electric spark wire cutting machine tool, characterized in that: The three-axis CNC spindle head has a Z-axis motion mechanism, a W1-axis motion mechanism and a W2-axis motion mechanism, and the up and down direction of the machine tool in the working state is defined as the Z direction, wherein the axes of the three axes, the Z-axis, the W1-axis and the W2-axis, are all arranged in 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, a wire guide tube positioning mechanism (38) 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 wire guide tube positioning mechanism (38) is positioned and installed on the Z-axis carriage (2); The Z-axis servo drive mechanism is positioned and mounted on the Z-axis carriage seat (1), 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 W1-axis motion mechanism comprises a W1-axis carriage (4), a W1-axis guide rail pair, a wire guide tube (19), an electrode wire feeding mechanism (20) and a W1-axis servo drive mechanism, wherein: The W1-axis carriage (4) is connected to the Z-axis carriage (2) via a W1-axis guide pair, and the W1-axis guide pair guides the W1-axis carriage (4) to perform precise movement in the W1-axis direction; The electrode wire feeding mechanism (20) is positioned and mounted on the W1-axis carriage (4); the wire guide tube (19) is fixedly mounted on the electrode wire feeding mechanism (20); in the assembled state, the axis of the wire guide tube (19) is parallel to the Z direction; the electrode wire feeding mechanism (20) is used to digitally feed the electrode wire (21) into or out of the wire guide tube (19); and the wire guide tube positioning mechanism (38) is used to position the lower part of the wire guide tube (19); The W1-axis servo drive mechanism is positioned and mounted on the Z-axis carriage (2), the W1-axis servo drive mechanism is drivingly connected to the W1-axis carriage (4), and is capable of driving the W1-axis carriage (4) to perform digital linear motion in the Z direction between designed strokes on the Z-axis carriage (2); The W2-axis motion mechanism comprises a W2-axis guide rail (6), a W2-axis first slider (7), a W2-axis second slider (8), a W2-axis first carriage (9), a W2-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 W2-axis servo drive mechanism, wherein: The W2-axis guide rail (6) is fixedly mounted on the Z-axis carriage seat (1); the W2-axis first slider (7) and the W2-axis second slider (8) are both mounted on the W2-axis guide rail (6); and the W2-axis first slider (7) and the W2-axis second slider (8) are both capable of making precise movements along the W2-axis guide rail (6) in the W2-axis direction; the W2-axis first slider (7) is located above the W2-axis second slider (8); The first carriage (9) of the W2 axis is fixedly connected to the first slider (7) of the W2 axis, and the second carriage (10) of the W2 axis is fixedly connected to the second slider (8) of the W2 axis; 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 W2 axis, and the lower action end (18) being fixedly connected to the second carriage (10) of the W2 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 W2 axis through the movable guide wheel seat (14), the axis of the movable guide wheel (12) is perpendicular to the Z direction, the axis of the electrode wire (21) passing around the movable guide wheel (12) and descending in the Z direction is coaxial with the axis of the wire guide hole of the wire guide tube (19), and 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 W2-axis servo drive mechanism is positioned and mounted on the Z-axis carriage seat (1), the W2-axis servo drive mechanism is drivingly connected to the W2-axis first carriage (9), and is capable of driving the W2-axis first carriage (9) and, through the tension detector (11), driving the W2-axis second carriage (10) to perform digital linear motion in the Z direction, wherein the motion range of the W2-axis first carriage (9) is between the highest position of the W1-axis carriage (4) in the Z direction and the upper limit position of the W2-axis first carriage (9); In the working state, the electrode wire section that passes around the movable guide wheel (12), descends in the Z direction, passes through the wire guide hole of the wire guide tube (19) to the 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 W2-axis second slider (8), the W2-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 W2-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 W2-axis first carriage (9). The machine tool control system can achieve constant tension control of the electrode wire (21) by servo control of the W2-axis driving the W2-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 three-axis CNC spindle head according to claim 1, characterized in that: The wire guide tube (19) is a slender tubular structure, with an axially penetrating wire guide hole arranged in the middle thereof, the wire guide hole being used to guide automatic wire threading, and the axis of the wire guide hole being parallel to the Z direction; The electrode wire feeding mechanism (20) is located above the wire guide tube (19) and is arranged directly opposite to the wire threading entrance of the wire guide tube (19); The wire guide tube positioning mechanism (38) is a positioning clamping structure for the lower part of the wire guide tube (19), and a positioning hole is provided on the positioning clamping structure. The positioning hole is used to position the outer cylindrical surface of the lower part of the wire guide tube (19). The positioning center axis of the positioning hole for the outer cylindrical surface of the lower part of the wire guide tube (19) is coaxial with the axis of the wire guide hole of the wire guide tube (19). The positioning clamping structure can automatically lock or release the lower part of the wire guide tube (19) in the positioning hole under the control of the machine tool control system. In the released state, the W1-axis servo drive mechanism can drive the wire guide tube (19) to move up and down along the axis direction in the positioning hole through the W1-axis drag plate (4).

3. The three-axis 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 three-axis 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 three-axis 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 small pulley (24), a large 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 transmission-connected with the small pulley (24); the axis of the Z-axis servo motor (3) is coaxial with the axis of the small pulley (24) and parallel to the Z direction; the small pulley (24) is transmission-connected with the large pulley (25) through a synchronous belt (26); the axis of the small pulley (24) is parallel to the axis of the large pulley (25); the large pulley (25) is transmission-connected with the Z-axis lead screw (27); the Z-axis lead screw (27) cooperates with the Z-axis nut (28); the axis of the large pulley (25), the axis of the Z-axis lead screw (27) and the axis of the Z-axis nut (28) are coaxial with each other and parallel to the Z direction; the Z-axis nut (28) is fixedly connected with the Z-axis carriage (2).

6. The three-axis CNC spindle head according to claim 1, characterized in that: The W1 axis guide pair is composed of a double cylindrical guide rod and a linear guide sleeve combination, wherein the double cylindrical guide rod and linear guide sleeve combination is composed of two cylindrical guide rods (29) and four linear bearings (30); Two bearing seats (31) are provided for the four linear bearings (30), two linear bearings (30) are fixedly mounted in parallel on one bearing seat (31), and the other two linear bearings (30) are fixedly mounted in parallel on the other bearing seat (31), the two bearing seats (31) are arranged at a distance in the upper and lower directions in the Z direction, and are fixedly mounted on the Z-axis carriage (2), the axes of the four linear bearings (30) on the two bearing seats (31) are coaxial in pairs in the upper and lower directions, and are parallel in pairs in the left and right directions and are parallel to the Z direction, thereby forming two groups of coaxial linear bearings (30); A positioning connection block (32) is provided for the two cylindrical guide rods (29). The two cylindrical guide rods (29) are correspondingly inserted into the inner holes of the two sets of coaxial linear bearings (30). The upper ends of the two cylindrical guide rods (29) are fixedly connected by the positioning connection block (32) and the center distance between the two cylindrical guide rods (29) is maintained. The lower ends of the two cylindrical guide rods (29) are fixedly connected to the W1 axis carriage (4) in a positioning manner.

7. The three-axis CNC spindle head according to claim 1, characterized in that: The W1-axis servo drive mechanism is composed of a W1-axis lead screw nut pair and a W1-axis servo motor (5) connected together; the W1-axis lead screw nut pair is composed of a W1-axis lead screw (33) and a W1-axis nut (34); the W1-axis servo motor (5) is fixedly mounted on the Z-axis carriage (2) via a W1-axis motor seat (35); the motor shaft of the W1-axis servo motor (5) is coaxially fixedly connected to the W1-axis lead screw (33); the motor shaft axis of the W1-axis servo motor (5) is parallel to the Z direction; the W1-axis nut (34) cooperates with the W1-axis lead screw (33); and the W1-axis nut (34) is fixedly connected relative to the W1-axis carriage (4).

8. The three-axis CNC spindle head according to claim 7, characterized in that: The W1-axis lead screw nut pair and the W1-axis servo motor (5) are servo motors with built-in lead screw nut pairs.

9. The three-axis CNC spindle head according to claim 1, characterized in that: The W2-axis servo drive mechanism is composed of a W2-axis lead screw nut pair and a W2-axis servo motor (16) connected together; the W2-axis lead screw nut pair is composed of a W2-axis lead screw (36) and a W2-axis nut (37); the motor shaft of the W2-axis servo motor (16) is coaxially fixedly connected to the W2-axis lead screw (36); the motor shaft axis of the W2-axis servo motor (16) is parallel to the Z direction; the W2-axis nut (37) cooperates with the W2-axis lead screw (36); and the W2-axis nut (37) is fixedly connected to the W2-axis first carriage (9).

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