Heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system

Abstract

The present invention belongs to the technical field of the development of automated equipment for the assembly and welding of large tanks for launch vehicles, and specifically relates to a heavy-load constant-pressure, constant-displacement controlled, high-torque output friction stir welding spindle system. The system comprises an X-axis motion device, a Y-axis motion device, an A-axis adjustment and locking device, and a high-torque output, heavy-load friction stir welding spindle. The X-axis motion device is provided with a Y-axis motion device, the Y-axis motion device is provided with an A-axis adjustment and locking device, and the A-axis adjustment and locking device is provided with a high-torque output, heavy-load friction stir welding spindle. The beneficial effect of the present invention is that it uses an integrated motor servo-driven heavy-load constant-pressure, constant-displacement friction stir welding spindle system to solve the technical problem of continuous and constant heavy-load, high-torque output during the friction stir welding forming process of thick-plate high-strength aerospace aluminum alloys, thereby achieving high-quality, efficient, and reliable automated welding of fuel tanks for a new generation of manned launch vehicles.

Description

Technical Field

[0001] The present invention belongs to the technical field of development of automated equipment for assembly and welding of large tanks of launch vehicles, and in particular relates to a heavy-load constant-pressure constant-displacement control high-torque output friction stir welding spindle system. Background Art

[0002] With the development of my country's space industry, higher demands are being placed on the carrying capacity of launch vehicles. Consequently, the scale of these structures is showing a significant trend of increasing. The weld zone thickness of the core stage tank of my country's new generation of manned launch vehicles reaches over 22 mm, and the total length reaches 40 meters. Using traditional fusion welding processes and methods presents significant development risks. Currently, welding is a key technology in the aerospace industry for rocket structure manufacturing. The application of welding processes and structures using various new advanced high-strength aluminum alloys (such as 2219 aluminum alloy and 2195 aluminum-lithium alloy) not only effectively improves the efficiency and reliability of launch vehicles, but also significantly promotes the overall development of the aerospace industry and enhances our ability to explore space. To effectively develop and utilize space resources, the development of various large-scale launch vehicles has become a critical foundation for the current aerospace industry. The application of advanced, efficient, and energy-saving friction stir welding (FSW) as a green manufacturing technology to replace traditional fusion welding, which consumes a lot of energy and produces high levels of pollution, has become a key trend in the development of large-scale launch vehicles. This is the key to achieving efficient and lightweight aerospace structures.

[0003] Friction stir welding is a novel metal welding process that utilizes the high temperatures generated by the rotation and extrusion of a stirrer to induce plastic flow of the metal material near the stirrer, forming a dense microstructure at the junction of the two workpieces, thereby achieving the welding of metal parts. Compared to traditional welding processes, friction stir welding offers advantages such as high joint quality, fewer defects, less deformation, reduced labor intensity, and a green and pollution-free welding process. Because the stirrer spindle in friction stir welding must continuously and stably output heavy shoulder pressure and high torque power to maintain the welding process, the spindle unit must have very high load-bearing rigidity and torque power output, which is its most significant feature that distinguishes it from other machining processes. Summary of the Invention

[0004] The purpose of the present invention is to provide a heavy-load constant pressure, constant displacement control, large torque output stir friction welding spindle system, which can solve the stir friction welding forming problem of the core stage tank of the new generation of manned carrier rockets. It adopts a synchronous large torque output mechanical transmission device to achieve stable output of heavy-load stir welding spindle power and torque. The stable output of the spindle top forging force is achieved by using a servo motor + reducer + ball screw nut drive. It is equipped with a high-precision grating scale and a pressure sensor to achieve full closed-loop control of constant pressure and constant displacement of the shoulder pressing feed movement. The position signal is collected at a high frequency and the signal is quickly transmitted to the control terminal numerical control system to realize the function of real-time adjustment of the spindle axial displacement adjustment, solve the technical problem of continuous and constant heavy load and large torque output in the stir friction welding forming process of thick plate high-strength aerospace aluminum alloy, and achieve high-quality, efficient and reliable automated welding forming of the fuel tank of the new generation of manned carrier rockets.

[0005] The technical solution of the present invention is as follows: a heavy-load constant pressure and constant displacement controlled large torque output stir friction welding spindle system includes an X-axis motion device, a Y-axis motion device, an A-axis adjustment locking device and a large torque output heavy-load stir friction welding spindle, the X-axis motion device is provided with a Y-axis motion device, the Y-axis motion device is provided with an A-axis adjustment locking device, and the A-axis adjustment locking device is provided with a large torque output heavy-load stir friction welding spindle.

[0006] The X-axis motion device includes an outer support slide box, an X-axis inner slide box, a screw elevator, a heavy-loaded roller linear guide, a reducer, an X-axis servo motor and a transmission shaft. The outer support slide box is made of carbon steel after welding and processing, and the various parts are screwed together. The X-axis inner slide box is made of carbon steel after welding into a whole and then processed as a whole. The slider of the heavy-loaded roller linear guide is screwed in the support slider limit groove of the outer slide box, and the guide rail of the heavy-loaded roller linear guide is screwed in the guide rail limit groove of the X-axis inner slide box. The outer support slide box and the X-axis inner slide box are formed into a sliding body through the slider and guide rail of the heavy-loaded roller linear guide. The base of the screw elevator is installed on the system support platform, the jacking nut is screwed on the X-axis inner slide box, the reducer is installed in conjunction with the X-axis servo motor, and is connected to the double-sided screw elevator through the transmission shaft.

[0007] The Y-axis motion device includes a Y-axis outer slide box, a Y-axis inner slide box, a heavy-loaded linear guide, a Y-axis servo motor, a low backlash reducer, a motor seat, a bearing fixing seat, a screw, a bearing support seat and a nut. The Y-axis outer slide box is screwed on the outer support slide box, the slider of the heavy-loaded linear guide is installed in the slider mounting groove on the inner wall of the Y-axis outer slide box, and the guide rail of the heavy-loaded linear guide is installed in the guide rail mounting groove on the outer wall of the Y-axis inner slide box. The connection between the Y-axis outer slide box and the Y-axis inner slide box is realized through the cooperation of the slider and the guide rail. The motor seat, the bearing fixing seat and the bearing support seat are respectively screwed on the outer support slide box. The low backlash reducer is driven by the Y-axis servo motor to transmit torque to the screw, driving the nut to move. The nut is screwed on the bottom of the Y-axis inner slide box.

[0008] The A-axis adjustment locking device includes a side set screw, an adjustment indicator dial, a spherical gasket, a locking flange tightening bolt, a locking flange top screw, a spindle locking flange, a spindle housing, a rotating shaft clamping flange, a rotating shaft, an aluminum-bronze bushing, a rotating shaft connector and a top locking bolt. The rotating shaft connector connects the spindle housing and the rotating shaft into a whole through a connecting bolt and is assembled in the Y-axis inner slide box. The aluminum-bronze bushing is installed on the Y-axis inner slide box, and the spindle locking flange is installed at the front end of the Y-axis inner slide box. The adjustment indicator dial is installed on the top of the rotating shaft, and the pointer rotates with the rotating shaft.

[0009] The A-axis adjustment locking device includes three locking steps.

[0010] The first locking device is located on the end face of the spindle locking flange. The spindle outlet of the spindle locking flange is elliptical, which is convenient for space avoidance after the spindle inclination angle is adjusted. The inclination angle is adjusted by adjusting the top screw on the flange. The spherical gasket and the locking flange tensioning bolt are passed through the strip holes on the spindle locking flange and locked with the corresponding screw holes on the spindle housing to achieve the first end face locking.

[0011] The second locking device refers to the side set screws on the inner side of the Y-axis inner slide box. After the inclination angle is adjusted to the right position, the side set screws are used to lock the inclination angle in the second process.

[0012] The third locking refers to the circumferential strip holes set on the outside of the rotating shaft clamping flange of the Y-axis inner slide box. After the inclination angle is adjusted to the right position, the top locking bolt is passed through the circumferential strip holes and locked with the corresponding screw holes on the spindle housing to perform the third locking.

[0013] The high-torque output heavy-load friction stir welding spindle is the terminal output module of the friction stir welding main machine, located in the spindle housing, and includes a stirring head clamping mechanism, a spindle front bearing group, a high-frequency pressure sensor, a spindle motor, a spindle rear bearing group and a retraction device. The two ends of the stirring head clamping mechanism are respectively mounted in the spindle front bearing group and the spindle rear bearing group, the middle part of the stirring head clamping mechanism is mounted in the spindle motor rotor, the spindle motor is mounted in the spindle housing, and the rear end of the stirring head clamping mechanism is connected to the retraction device.

[0014] The Y-axis inner sliding box is provided with a grating ruler probe, and the grating ruler is correspondingly installed on the inner wall of the Y-axis outer sliding box.

[0015] The beneficial effects of the present invention are: 1. The present invention adopts an integrated motor servo-driven heavy-load constant-pressure constant-displacement stir friction welding spindle system to solve the technical problem of continuous and constant heavy-load and large-torque output during the stir friction welding forming process of thick plate high-strength aerospace aluminum alloy, and realize high-quality, efficient and reliable automated welding forming of the new generation of manned carrier rocket fuel tanks.

[0016] 2. The present invention's spindle axial lift, or X-axis motion adjustment module, enables alignment of the spindle relative to the weld seam and repair welding. Synchronous servo control drives two self-locking spiral elevators. Displacement sensors and high-precision, high-rigidity, heavy-duty roller-type linear guides are installed between the base and the lift seat, enabling high-precision axial movement control of the spindle and ensuring rigidity and stability during transmission.

[0017] 3. The Y-axis motion feed of the friction stir welding spindle is realized by a servo motor + low backlash reducer + ball screw nut drive, and is equipped with a high-precision grating scale and pressure sensor to realize the constant pressure and constant displacement full closed-loop control of the shoulder pressing feed motion. The heavy-load friction stir welding spindle can realize two control modes: constant pressure control and constant displacement control. It solves the problem that the shoulder pressing pressure or displacement under heavy-load constant pressure conditions during the friction stir welding of medium and thick aluminum alloy wall panels must be strictly output in accordance with the control system requirements. At the same time, the forging force or pressing position of the shaft stirring head during welding can be collected and fed back to the control system in real time, which is convenient for the operator to control the welding process in real time, with fast response and high control accuracy, and realize high-quality, efficient and reliable automated welding of aerospace high-strength aluminum alloy components.

[0018] 4. The new A-axis process inclination adjustment device (welding inclination adjustment locking device) can realize the process inclination setting, micro-adjustment and reliable locking functions of the main shaft along the welding direction (i.e. circumferential tangent) of ±5° when welding the tank circumferential seam.

[0019] 5. The heavy-load constant pressure and constant displacement control high torque output friction stir welding spindle solves the friction stir welding forming of the core stage tank of the new generation of manned carrier rockets. It adopts a synchronous high torque output mechanical transmission device, a high-rigidity friction stir welding spindle bearing suitable for heavy-load stir welding conditions, a spindle motor synchronous rotation and speed detection control device, and an internal circulation water cooling system to achieve stable output of power and torque of the heavy-load stir welding spindle.

[0020] 6. The spindle constant pressure and constant displacement control principle is particularly suitable for stir friction welding process. It can be promoted and applied to high, medium and low thickness stirring host units, and can also provide technical support for other heavy-load non-standard equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the heavy-load constant pressure constant displacement control and high torque output friction stir welding spindle system;

[0022] Figure 2 This is a motion diagram of a heavy-load constant pressure constant displacement control high torque output friction stir welding spindle system;

[0023] Figure 3Schematic diagram of the heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system provided by the present invention;

[0024] Figure 4 This is the first schematic diagram of the X-axis motion device;

[0025] Figure 5 is a second schematic diagram of the X-axis motion device;

[0026] Figure 6 This is the first schematic diagram of the Y-axis motion device;

[0027] Figure 7 is a second schematic diagram of the Y-axis motion device;

[0028] Figure 8 is the third schematic diagram of the Y-axis motion device;

[0029] Figure 9 This is the first schematic diagram of the A-axis adjustment locking device;

[0030] Figure 10 This is the second schematic diagram of the A-axis adjustment locking device;

[0031] Figure 11 This is a schematic diagram of a high-torque output heavy-load friction stir welding spindle;

[0032] Figure 12 The first configuration diagram of the spindle bearing assembly for high torque output and heavy load friction stir welding;

[0033] Figure 13 The second configuration diagram of the spindle bearing assembly for high torque output and heavy load friction stir welding;

[0034] Figure 14 Schematic diagram of the cooling cycle for the friction stir welding spindle bearing;

[0035] Figure 15 Schematic diagram of the feed motion grating ruler of the friction stir welding actuator;

[0036] Figure 16 Schematic diagram of the pressure sensor for the feed motion of the friction stir welding actuator.

[0037] In the figure: 1X-axis motion device, 2Y-axis motion device, 3A-axis adjustment locking device, 4High torque output heavy-duty friction stir welding spindle, 5External support slide box, 6X-axis inner slide box, 7Screw elevator, 8Heavy-duty roller linear guide, 9Reducer, 10X-axis servo motor, 11Transmission shaft, 12Y-axis outer slide box, 13Y-axis inner slide box, 14Heavy-duty linear guide, 15Y-axis servo motor, 16Low backlash reducer, 17Motor seat, 18Bearing fixed seat, 19Lead screw, 20Bearing support seat, 21 nut, 22 side set screw, 23 adjustment indicator dial, 24 spherical gasket, 25 locking flange tightening bolt, 26 locking flange top screw, 27 spindle locking flange, 28 spindle housing, 29 rotating shaft clamping flange, 30 rotating shaft, 31 aluminum bronze bushing, 32 rotating shaft connector, 33 top locking bolt, 34 stirring head clamping mechanism, 35 spindle front bearing group, 36 high-frequency pressure sensor, 37 spindle motor, 38 spindle rear bearing group, 39 retraction device, 40 grating ruler, 41 probe. DETAILED DESCRIPTION

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] The annular seam of the common bottom tank of the new generation of manned carrier rocket adopts a vertical assembly welding process. The tank structure material is 4-30mm2219 and 2195 and other high-strength aluminum alloys commonly used in aerospace. The present invention provides a heavy-load constant pressure constant displacement control large torque output stir friction welding spindle system suitable for the tank vertical assembly welding mode. Since the annular seam of the tank adopts a vertical stir friction welding process, the tank is fixed during the welding process, and the heavy-load constant pressure constant displacement control large torque output stir friction welding spindle system rotates around the tank to complete the annular seam welding. The welding spindle system is installed on the basic rotary platform of the welding equipment and rotates 360 degrees with the rotary platform to complete the annular seam welding of the tank body. Figure 1 The heavy-duty constant-pressure, constant-displacement control and high-torque output friction stir welding spindle system withstands significant upsetting and forward resistance during welding, providing sufficient rigidity. The welding actuator utilizes a stable and reliable heavy-duty guide structure. While meeting operational requirements, the stir force point height and reach are designed to ensure uniform force distribution during welding, avoiding bending moments on local components and ensuring a smooth and stable welding process. This system also meets the requirements for retractable friction stir welding of materials with a thickness of at least 30 mm.

[0040] The motion form created by the present invention is as follows Figure 2 As shown:

[0041] (1) X-axis - The friction stir welding spindle of the welding actuator moves up and down along the base guide rail (moves along the axial direction of the box product).

[0042] (2) Y-axis - the friction stir welding spindle of the welding actuator moves back and forth along the radial guide rail of the actuator slide box (feeding and moving along the radial direction of the tank product, and the stirring head shoulder presses in).

[0043] (3) A-axis - welding inclination adjustment movement of welding main machine components (mechanical adjustment and locking).

[0044] (4) SP axis - welding main spindle rotation motion, N × 360° continuous rotation.

[0045] (5) W axis - welding spindle retraction movement.

[0046] like Figure 3 As shown, the heavy-load constant pressure and constant displacement controlled large torque output friction stir welding spindle system includes an X-axis motion device 1, a Y-axis motion device 2, an A-axis adjustment locking device 3 and a large torque output heavy-load friction stir welding spindle 4. The Y-axis motion device 2 is installed on the X-axis motion device 1, the A-axis adjustment locking device 3 is installed in the Y-axis motion device 2, and the large torque output heavy-load friction stir welding spindle 4 is installed on the A-axis adjustment locking device 3.

[0047] like Figure 4 and 5 As shown, the X-axis motion device includes an outer support slide 5, an X-axis inner slide 6, a screw elevator 7, a heavy-duty roller linear guide 8, a reducer 9, an X-axis servo motor 10 and a transmission shaft 11. The outer support slide 5 is made of carbon steel after welding and processing, and the various parts are screwed together. Adjustment gaskets are used between the various parts to ensure the installation accuracy of the X-guide rail slider. The X-axis inner slide 6 is made of carbon steel after welding and processing as a whole. The slider of the heavy-duty roller linear guide 8 is screwed into the support slider limit groove of the outer support slide 5, and the guide rail of the heavy-duty roller linear guide 8 is screwed into the guide rail limit groove of the X-axis inner slide 6. The slider and guide rail of the heavy-duty roller linear guide 8 cooperate to form a sliding body between the outer support slide 5 and the X-axis inner slide 6. The base of the screw elevator 7 is installed on the system support platform, and the lifting nut is screwed to the X-axis inner slide 6. The speed reducer 9 is installed in conjunction with the X-axis servo motor 10 and is connected to the double-sided screw elevator 7 through the transmission shaft 11 to establish a power transmission relationship.

[0048] The X-axis motion device enables the spindle to move vertically, with a spindle lifting stroke of 100mm. The main function of this motion axis is to achieve the requirements of weld height alignment and repair welding. The lifting drive uses a servo motor 10 to control and drive two screw elevators 7 to lift and lower synchronously. The screw elevator lead screw is Tr80X12, and the rated dynamic load of a single unit is up to 200kN. Six high-precision, high-rigidity, heavy-duty roller-type linear guides 8 are used for precise guidance and bearing of the spindle along the X-axis, ensuring the rigidity and stability of the above components during the transmission process. The elevator has a self-locking function, and a displacement sensor is installed between the base and the lifting seat, so that the spindle can achieve high-precision vertical movement.

[0049] like Figure 6-8 As shown, the Y-axis motion device includes a Y-axis outer slide box 12, a Y-axis inner slide box 13, a heavy-loaded linear guide 14, a Y-axis servo motor 15, a low backlash reducer 16, a motor seat 17, a bearing fixing seat 18, a lead screw 19, a bearing support seat 20 and a nut 21. The Y-axis outer slide box 12 is screwed onto the outer support slide box 5, and the slider of the heavy-loaded linear guide 14 is installed in the slider mounting groove on the inner wall of the Y-axis outer slide box 12. The guide rail of the heavy-loaded linear guide 14 is installed in the guide rail mounting groove on the outer wall of the Y-axis inner slide box 13. The connection between the Y-axis outer slide box 12 and the Y-axis inner slide box 13 is realized through the cooperation of the slider and the guide rail. The motor seat 17, the bearing fixing seat 18, and the bearing support seat 20 are respectively screwed on the outer support slide box 5, forming the driving part of the Y-axis motion device. The low backlash reducer 16 is driven by the Y-axis servo motor 15 to transmit torque to the screw 19, driving the nut 21 to move. The nut 21 is screwed on the bottom of the Y-axis inner slide box 13, thereby realizing the Y-direction movement of the Y-axis inner slide box 13 and the main shaft.

[0050] The Y-axis (shoulder press-in) motion mechanism achieves a 485mm Y-axis spindle feed travel. Equipped with a high-precision linear scale and pressure sensor, it implements fully closed-loop control of the shoulder press-in feed motion with constant pressure and displacement. Position and pressure signals are acquired at high frequency and rapidly transmitted to the terminal CNC system, enabling real-time adjustment of the spindle's axial displacement and pressure output. This ensures high-quality, efficient, reliable, and fully automated welding performance for the friction stir welding head. The Y-axis (shoulder press-in) drive mechanism meets the continuous welding requirements of a spindle rated forging force ≥150kN and a rated forward force ≥75kN for products with thicknesses from 4mm to 30mm.

[0051] like Figure 9 and 10As shown, the A-axis adjustment and locking device allows for setting, adjusting, and locking the ±5° process inclination angle in the welding direction (i.e., circumferential tangential direction) during tank circumferential seam welding. It includes a side set screw 22, an adjustment indicator dial 23, a spherical washer 24, a locking flange tensioning bolt 25, a locking flange top screw 26, a spindle locking flange 27, a spindle housing 28, a rotating shaft pressure flange 29, a rotating shaft 30, an aluminum-bronze bushing 31, a rotating shaft connector 32, and a top locking bolt 33. The rotating shaft connector 32 connects the spindle housing 28 and the rotating shaft 30 via connecting bolts, forming a single unit assembled within the Y-axis inner slide case 13. To ensure smooth rotation, the aluminum-bronze bushing 31 is installed on the Y-axis inner slide case 13, and the rotating shaft pressure flange 29 is bolted on to lock the shaft axially. Furthermore, a spindle locking flange 27 is installed at the front end of the Y-axis inner slide case 13 to lock the spindle after angle adjustment. The A-axis process inclination adjustment device is provided with an adjustment indicator dial 23 installed on the top of the rotating shaft 30. The pointer rotates with the rotating shaft 30 with an adjustment accuracy of 0.1°, which is convenient for the operator to determine the inclination reading and return to zero adjustment. After the spindle angle is adjusted, three locking steps are required: the first locking device is located on the end face of the spindle locking flange 27. The spindle outlet of the spindle locking flange 27 is designed to be elliptical, which is convenient for inclination adjustment without interference. After the inclination is adjusted to the right position, the spherical gasket 24 and the locking flange 25 are used to tighten the bolts through the strip holes on the locking flange of the spindle 27 and the corresponding screw holes on the spindle housing 28 to achieve the first end face locking; the second locking device refers to the side tightening screws 22 on the inner side of the Y-axis inner slide box 13. After the inclination is adjusted to the right position, the side tightening screws 22 perform the second process inclination locking; the third locking refers to the circumferential strip holes set on the outer side of the rotating shaft pressing flange of the Y-axis inner slide box 13. After the inclination is adjusted to the right position, the top locking bolts 33 are passed through the circumferential strip holes and matched with the corresponding screw holes on the spindle housing 28 to lock for the third locking.

[0052] like Figure 11 As shown, the high-torque output heavy-load stir friction welding spindle 4 is the terminal output module of the stir friction welding main machine, which is located in the spindle housing 28 and includes a stirring head clamping mechanism 34, a spindle front bearing group 35, a high-frequency pressure sensor 36, a spindle motor 37, a spindle rear bearing group 38 and a retraction device 39. The two ends of the stirring head clamping mechanism 34 are respectively mounted in the spindle front bearing group 35 and the spindle rear bearing group 38. The middle part of the stirring head clamping mechanism 34 is rotated with the spindle motor 37. The spindle motor 37 is mounted in the spindle housing 28. The end of the retraction device 39 of the stirring head clamping mechanism 34 is connected to the retraction device 39.

[0053] The friction stir welding spindle torque output is provided by a spindle motor 37 mounted inside the spindle housing 28. This motor utilizes a direct-drive, internally synchronous hollow spindle motor, with a hollow core for the retraction mechanism. This motor features a compact design, high torque output, smooth rotation, and low noise. The spindle also incorporates an external encoder for precise spindle speed measurement, achieving a stable output torque of 820 Nm and a speed of 950 rpm for extended periods, meeting the requirements for conventional, retractable, dual-shoulder welding of aerospace high-strength aluminum alloy products with a thickness of 4-30 mm.

[0054] The bearing rigidity of the main shaft is mainly achieved through the configuration of the stir friction welding main shaft bearing group. The present invention adopts a special stirring main shaft bearing group configuration mode. The main shaft front bearing group 35 is composed of a double-row cylindrical roller and a double-direction thrust angular contact ball bearing, which has high rigidity. The main shaft rear bearing group 38 uses double-row cylindrical roller bearings. The front bearing group mainly bears the stir friction load to ensure rotation accuracy. The main shaft rear bearing group 38 greatly increases the main shaft rigidity and accommodates the main shaft length error caused by environmental changes such as temperature. It can ensure that the end face runout of the welding main shaft is ≤0.04mm and the radial runout of the welding main shaft is ≤0.04mm.

[0055] The mixing spindle generates a significant amount of heat under high speed and heavy load. The continuous accumulation of this heat can significantly impact its performance. The mixing spindle's internal motor and spindle bearings are the two primary heat sources. To ensure full spindle power output, the motor's inherent heat generation must be kept within a controllable temperature range through additional cooling measures. Siemens' internal synchronous permanent magnet motors typically use a water-cooling circuit to dissipate this heat, and a water-cooling circuit is added to the spindle's exterior.

[0056] The spindle front end bearing group bears the main load of stir friction welding. The spindle bearing temperature will also rise during operation, affecting the spindle bearing load and life. Therefore, water cooling circulation should also be added to ensure that the temperature rise does not exceed the maximum allowable bearing temperature. The water cooling circulation is as follows: Figure 14 As shown, the front bearing group and the spindle motor can be cooled.

[0057] The friction stir welding spindle is equipped with a high-frequency pressure sensor 36, which enables real-time detection and feedback of the forging force and forward resistance, enabling constant pressure and displacement control of the spindle during stir welding. The heavy-duty friction stir welding spindle can implement both constant pressure and constant displacement control. This ensures that the shoulder pressure or displacement output is strictly consistent with the control system's requirements during heavy-duty constant-pressure conditions during friction stir welding of medium-thick aluminum alloy panels. Furthermore, the forging force or position of the stir head during welding is collected and fed back to the control system in real time, facilitating real-time control of the welding process by the operator, achieving high-quality, efficient, and reliable automated welding of aluminum alloy components.

[0058] The Y-axis (shoulder pressing) motion feed of the stir friction welding spindle is realized by a servo motor + low backlash reducer + ball screw nut drive, and is equipped with a high-precision grating scale and pressure sensor to realize constant pressure and constant displacement full closed-loop control of the shoulder pressing feed motion. The position / pressure signal is collected at high frequency, and the signal is quickly transmitted to the control terminal CNC system to realize the real-time adjustment of the spindle axial displacement / pressure output adjustment function, so that the stir friction welding head has high quality, high efficiency, reliability and fully automated welding performance.

[0059] (1) Constant displacement control: Relative movement occurs between the Y-axis outer slide box 12 and the Y-axis inner slide box 13 to achieve shoulder pressing. A grating scale probe 41 is installed at a suitable position on the Y-axis inner slide box 13, and a grating scale 40 is installed on the inner wall of the Y-axis outer slide box 12. The grating scale is used to realize constant displacement full closed-loop control transmission. After closed-loop control is realized, the positioning accuracy reaches 0.03mm and the repeat positioning accuracy reaches 0.02mm.

[0060] (2) Constant pressure control: A set of high-frequency pressure sensors 36 are installed at the connection between the stir friction welding spindle and the spindle housing to achieve real-time detection and feedback of the upsetting force and forward resistance. By real-time acquisition of the axial force signal measured by the force sensor, the theoretical calculation set by the program is performed to obtain the axial upsetting force data. The obtained upsetting force data is connected to the CNC system through the pressure sensor signal adapter. While the CNC system displays the upsetting force data in real time, it compares the collected real-time upsetting force with the upsetting force data value set by the system, and controls the pressing amount of the mechanism in real time, thereby achieving constant pressure control of stir friction welding. The pressure sensor and signal acquisition system use internationally renowned high-frequency data acquisition feedback pressure sensors, and the measurement range meets the measurement requirements of the spindle's ultimate upsetting force of 180kN.

Claims

1. Heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system, characterized by: It includes an X-axis motion device, a Y-axis motion device, an A-axis adjustment locking device and a large torque output heavy-load stir friction welding spindle. The X-axis motion device is provided with a Y-axis motion device, the Y-axis motion device is provided with an A-axis adjustment locking device, and the A-axis adjustment locking device is provided with a large torque output heavy-load stir friction welding spindle. The X-axis motion device includes an outer support slide box, an X-axis inner slide box, a screw elevator, a heavy-loaded roller linear guide, a reducer, an X-axis servo motor and a transmission shaft. The outer support slide box is made of carbon steel after welding and processing, and the various parts are screwed together. The X-axis inner slide box is made of carbon steel welded into a whole and then processed as a whole. The slider of the heavy-loaded roller linear guide is screwed into the support slider limit groove of the outer slide box, and the guide rail of the heavy-loaded roller linear guide is screwed into the guide rail limit groove of the X-axis inner slide box. The outer support slide box and the X-axis inner slide box are formed into a sliding body through the slider and guide rail of the heavy-loaded roller linear guide. The base of the screw elevator is installed on the system support platform, the jacking nut is screwed on the X-axis inner slide box, the reducer is installed in conjunction with the X-axis servo motor, and is connected to the double-sided screw elevator through the transmission shaft. The Y-axis motion device includes a Y-axis outer slide box, a Y-axis inner slide box, a heavy-loaded linear guide, a Y-axis servo motor, a low backlash reducer, a motor seat, a bearing fixing seat, a lead screw, a bearing support seat and a nut. The Y-axis outer slide box is screwed on the outer support slide box, the slider of the heavy-loaded linear guide is installed in the slider mounting groove on the inner wall of the Y-axis outer slide box, and the guide rail of the heavy-loaded linear guide is installed in the guide rail mounting groove on the outer wall of the Y-axis inner slide box. The connection between the Y-axis outer slide box and the Y-axis inner slide box is realized through the cooperation of the slider and the guide rail. The motor seat, the bearing fixing seat and the bearing support seat are respectively screwed on the outer support slide box. The low backlash reducer is driven by the Y-axis servo motor to transmit torque to the lead screw, driving the nut to move, and the nut is screwed on the bottom of the Y-axis inner slide box; The A-axis adjustment locking device includes a side set screw, an adjustment indicator dial, a spherical gasket, a locking flange tightening bolt, a locking flange top screw, a spindle locking flange, a spindle housing, a rotating shaft clamping flange, a rotating shaft, an aluminum-bronze bushing, a rotating shaft connector and a top locking bolt. The rotating shaft connector connects the spindle housing and the rotating shaft into a whole through a connecting bolt and is assembled in the Y-axis inner slide box. The aluminum-bronze bushing is installed on the Y-axis inner slide box, and the spindle locking flange is installed at the front end of the Y-axis inner slide box. The adjustment indicator dial is installed on the top of the rotating shaft, and the pointer rotates with the rotating shaft.

2. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 1, characterized in that: The A-axis adjustment locking device includes three locking stages, and the three locking stages include a first locking device, a second locking device and a third locking device.

3. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 2, characterized in that: The first locking device is located on the end face of the main shaft locking flange. The main shaft outlet of the main shaft locking flange is elliptical. The spherical gasket and the locking flange tightening bolt are passed through the strip holes on the main shaft locking flange and locked with the corresponding screw holes on the main shaft housing to achieve the first end face locking.

4. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 2, characterized in that: The second locking device refers to the side set screw on the inner side of the Y-axis inner slide box. After the inclination angle is adjusted to the right position, the side set screw performs the second process inclination locking.

5. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 2, characterized in that: The third locking refers to the circumferential strip holes set on the outside of the rotating shaft clamping flange of the Y-axis inner slide box. After the inclination angle is adjusted to the right position, the top locking bolt is passed through the circumferential strip holes and locked with the corresponding screw holes on the spindle housing to perform the third locking.

6. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 1, characterized in that: The high-torque output heavy-load friction stir welding spindle is the terminal output module of the friction stir welding main machine, located in the spindle housing, and includes a stirring head clamping mechanism, a spindle front bearing group, a high-frequency pressure sensor, a spindle motor, a spindle rear bearing group and a retraction device. The two ends of the stirring head clamping mechanism are respectively mounted in the spindle front bearing group and the spindle rear bearing group, the middle part of the stirring head clamping mechanism is mounted in the spindle motor rotor, the spindle motor is mounted in the spindle housing, and the rear end of the stirring head clamping mechanism is connected to the retraction device.

7. The heavy-load constant pressure constant displacement control large torque output friction stir welding spindle system according to claim 1, characterized in that: The Y-axis inner sliding box is provided with a grating ruler probe, and the grating ruler is correspondingly installed on the inner wall of the Y-axis outer sliding box.

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