Linear friction welding wheel disc clamping tool and closed-loop control method thereof

Abstract

The application provides a linear friction welding to-be-welded disc clamping tool and a closed-loop control method thereof, and belongs to the technical field of linear friction welding equipment. The linear friction welding to-be-welded disc clamping tool comprises a base arranged on a workbench, a dividing device arranged on the base, wherein the dividing device comprises a dividing disc, a mandrel, a first expansion hydraulic sleeve and a pressing device. The lower end of the mandrel is connected to the center of the dividing device, and the upper end of the mandrel is used for penetrating into the center hole of the to-be-welded disc. The first expansion hydraulic sleeve is sleeved outside the mandrel and is used for radial expansion to clamp the inner wall of the center hole of the to-be-welded disc. The pressing device is connected to the upper end of the mandrel and is used for axially pressing the to-be-welded disc. A pressure sensor is arranged between the pressing device and the to-be-welded disc or the first expansion hydraulic sleeve and is used for monitoring the axial clamping force in real time. The application adopts a composite clamping mode of "center hole positioning + radial expansion + axial pressing", combines the uniform force exertion characteristics of expansion, and improves the clamping stiffness and anti-vibration ability.

Description

Technical Field

[0001] This invention relates to the field of linear friction welding forming technology for integral bladed disks, specifically to a clamping fixture for linear friction welding of a wheel disk to be welded and its closed-loop control method. Background Technology

[0002] The performance requirements of the new generation of aero engines—high thrust-to-weight ratio, low energy consumption, and long range—have driven engine components to exhibit characteristics of "integration and lightweighting." Replacing the traditional integrated bladed disk components that use tenons and mortises to connect the blades and the disk with integral bladed disk components can effectively improve connection reliability and structural compactness, which is beneficial for improving the engine's thrust-to-weight ratio and aerodynamic efficiency, while reducing component weight, fuel consumption, and exhaust volume.

[0003] Linear friction welding (LFD) is a novel manufacturing process for integral bladed disks (IBDs), effectively addressing the limitations of traditional IBD manufacturing methods, such as significant material waste, high costs, and long production cycles. In the LFD process, the design of the clamping fixture for the disk to be welded is crucial for achieving high-quality welding. The main challenges lie in high-rigidity constraints, precise positioning, and adaptability to complex loads. Firstly, the LFD process involves high-frequency reciprocating vibration and significant axial upsetting forces. The fixture must possess sufficient overall rigidity and fatigue resistance to prevent deformation or loosening during vibration, which would affect the stability of the weld interface and the weld quality. Secondly, disk-type parts typically have complex structures, large dimensions, and extremely high requirements for coaxiality and positional accuracy. This places stringent demands on the positioning and clamping accuracy of the fixture. The fixture must not only ensure the spatial stability of the disk during welding but also achieve high-precision alignment to ensure uniform contact at the weld interface; otherwise, problems such as incomplete fusion or uneven microstructure may occur. Finally, the tooling also needs to balance versatility and operability. Under the premise of ensuring high rigidity and high precision, it is a practical challenge to achieve quick clamping, reliable force transmission, and adaptability to different specifications of wheel discs.

[0004] In the prior art, for example, Chinese patent application CN202411149879.6 discloses a multi-stage integral bladed disk milling fixture, which uses a central positioning mandrel, an internal cavity support mechanism (mechanical support bar), and an exhaust-side clamping mechanism to clamp the bladed disk. However, this fixture is mainly used for milling, and its mechanical support bar structure has shortcomings in terms of clamping force uniformity and controllability, and lacks real-time monitoring of clamping force, making it difficult to adapt to the complex load conditions of high-frequency vibration and large upsetting force in linear friction welding. In addition, the prior art lacks indexing function integration for the multi-station welding requirements of linear friction welding. Summary of the Invention

[0005] To address the aforementioned issues, this invention proposes a linear friction welding wheel clamping fixture and its closed-loop control method based on the composite clamping principle of "center hole positioning + radial expansion + axial compression," combined with an indexing device, multi-sensor monitoring, and a closed-loop control strategy.

[0006] The technical solution adopted in this invention is: A clamping fixture for a wheel disc to be welded in linear friction welding includes: The base is set on the workbench; The indexing device includes an indexing plate, a second expansion hydraulic sleeve, and an angle encoder. The indexing plate is radially expanded and connected to the base through the second expansion hydraulic sleeve, and the angle encoder is used to detect the indexing angle in real time. The mandrel has its lower end fixedly connected to the center of the indexing device, and its upper end is used to pass through the center hole of the wheel to be welded. The first expansion hydraulic sleeve is sleeved on the outer side of the upper end of the mandrel and is used to radially expand and tighten the inner wall of the center hole of the wheel to be welded, so that the wheel to be welded is fixed to the mandrel. A clamping device, connected to the upper end of the mandrel, is used to axially clamp the wheel disc to be welded; A pressure sensor, disposed between the clamping device and the wheel disc to be welded or the first expansion hydraulic sleeve, is used to monitor the axial clamping force and hydraulic expansion pressure in real time; and The control unit is connected to the indexing device, the first tightening hydraulic sleeve, the second tightening hydraulic sleeve, the clamping device, and the pressure sensor, respectively, and is used to receive real-time data and perform closed-loop control.

[0007] Furthermore, in the clamping fixture, the upper part of the base has an inclined surface, and a cylindrical shaft is arranged perpendicular to the inclined surface; the second expansion hydraulic sleeve is sleeved outside the cylindrical shaft, used to radially expand and tighten the blind hole provided at the bottom of the indexing plate, and the indexing device fixing nut and the bolt lock the indexing plate to the base.

[0008] Furthermore, in the clamping fixture, the mandrel is a stepped shaft, including a lower large-diameter section and an upper small-diameter section, and the wheel to be welded is fixed to the upper small-diameter section; the lower large-diameter section is provided with multiple screw holes for fixed connection with the indexing device by mandrel bolts.

[0009] Furthermore, the clamping fixture also includes a temperature sensor and / or a vibration sensor; the temperature sensor is disposed on the mandrel, the first expansion hydraulic sleeve, or the clamping device, and is used to monitor the temperature of the fixture; the vibration sensor is disposed on the base or the indexing device, and is used to monitor high-frequency vibration signals during the welding process; both the temperature sensor and the vibration sensor are signal-connected to the control unit.

[0010] Furthermore, in the clamping fixture, a metal rubber damping pad or a composite damping pad is provided between the base and the worktable and / or between the indexing plate and the wheel to be welded.

[0011] Furthermore, in the clamping fixture, the clamping device is a clamping nut, which is threadedly connected to the upper end of the mandrel, and the lower surface of the wheel to be welded contacts the upper surface of the mandrel.

[0012] Furthermore, in the clamping fixture, the clamping device is a hydraulic pressure head, which is located at the upper end of the mandrel and is used to provide an adjustable axial clamping force.

[0013] Furthermore, in the aforementioned clamping fixture, the hydraulic pressure head has a round cap-shaped structure with a threaded hole in the middle that mates with the mandrel. The hydraulic pressure head is also equipped with a pressure adjustment structure and a pressure indicator.

[0014] A closed-loop control method for a linear friction welding wheel clamping fixture with a central hole, employing the clamping fixture as described in any of the above-mentioned methods, includes the following steps: S1 Parameter Preset: Based on the material, diameter, thickness, center hole size, and linear friction welding process parameters of the wheel to be welded, preset the pressure of the first tightening hydraulic sleeve, the pressure of the second tightening hydraulic sleeve, the allowable range of axial clamping force, the tooling temperature alarm threshold, the allowable error of the indexing angle, and the vibration alarm threshold, and input the above parameters into the control unit; S2 Clamping and Positioning: Install the wheel to be welded onto the mandrel, and insert the mandrel into the center hole of the wheel to be welded; activate the first expansion hydraulic sleeve to radially expand and position the center hole of the wheel to be welded, and at the same time, use the clamping device to axially clamp the end face of the wheel to be welded, thus completing the initial clamping; S3 Indexing Locking: The indexing device drives the welding wheel to rotate to the predetermined welding angle, and the angle encoder detects the current indexing angle in real time; when the deviation between the detected angle and the target angle is less than the preset allowable error, the indexing device locks; when the angle deviation exceeds the limit, the control unit issues a correction command to make the indexing device readjust its positioning. S4 Multi-source data acquisition: The pressure sensor acquires the axial clamping force and hydraulic expansion pressure in real time; the temperature sensor acquires the temperature near the mandrel, expansion hydraulic sleeve or clamping device in real time; the angle encoder acquires the indexing angle in real time; and the vibration sensor acquires the high-frequency vibration signal during the welding process and transmits the acquired data synchronously to the control unit. S5 Data Judgment and Threshold Comparison: The control unit compares the real-time collected pressure, temperature, angle and vibration data with preset thresholds to determine whether the pressure of the first tightening hydraulic sleeve, the pressure of the second tightening hydraulic sleeve, the axial clamping force, the tooling temperature, the indexing angle deviation and the vibration amplitude are within the allowable range. S6 Online Adjustment and Compensation: When the pressure is lower than the preset value, the control unit controls the hydraulic station to replenish the pressure; when the pressure is higher than the upper limit of allowable pressure, the control unit controls the hydraulic station to release pressure or stop pressurizing; when the temperature exceeds the set threshold, the circulating cooling system is started or the cooling flow is increased; when the indexing angle deviation exceeds the limit, the control unit controls the indexing device to make fine-tuning of the angle; when the vibration amplitude exceeds the set threshold, an alarm is issued and the welding program is paused. S7 Welding Process Closed-Loop Monitoring: During the linear friction welding process, the control unit continuously receives feedback signals from pressure sensors, temperature sensors, angle encoders and vibration sensors, and dynamically adjusts hydraulic pressure, cooling flow and indexing locking state according to real-time deviations to achieve stable clamping force, thermal deformation control and position accuracy maintenance during the welding process. S8 Post-weld release and data recording: After welding is completed, the control unit stops the welding interlock signal and releases the axial clamping, center hole expansion and indexing locking states in sequence; at the same time, the pressure, temperature, angle and vibration data during this welding process are recorded for subsequent quality traceability, process parameter optimization and batch welding consistency control.

[0015] Furthermore, in the closed-loop control method, in step S6, when the angle detection value exceeds the preset allowable error, the control unit issues an alarm signal and prohibits the welding equipment from entering the welding program.

[0016] The beneficial effects of the above technical solution are as follows: (1) This invention provides a clamping fixture for a linear friction welding wheel, which adopts a composite clamping method of "center hole positioning + radial expansion + axial compression". Combined with the uniform force application characteristics of expansion, the clamping stiffness and vibration resistance are improved. The constraints on the wheel in the radial, axial and circumferential directions are more defined, which can ensure the relative position accuracy of the interface to be welded. The interface contact state is more uniform during linear friction welding, and the distribution of frictional heat input and plastic flow is more stable, which is conducive to forming a continuous, dense and consistent welded joint, and reducing complex load adaptation problems such as incomplete welding, interface tilting and uneven structure caused by clamping eccentricity, local loosening or uneven force.

[0017] (2) Linear friction welding involves not only significant axial upsetting force but also high-frequency reciprocating loads. If only a single clamping method is used, the wheel disk to be welded, especially the thin web area, is prone to local deflection or vibration amplification. The clamping fixture provided by this invention employs a composite clamping method that can more evenly transfer the load to the high-rigidity area, shorten the force transmission path, reduce local stress concentration, and effectively reduce elastic deformation during welding and geometric deviations after welding. This is particularly important for integral bladed disks, which have high requirements for blade position accuracy, installation angle accuracy, and overall dynamic balance.

[0018] (3) The clamping fixture provided by the present invention is equipped with a pressure sensor, which realizes real-time monitoring and control of axial clamping force, avoids welding defects caused by insufficient or excessive clamping force, and improves the stability and consistency of the welding process.

[0019] (4) The clamping fixture provided by the present invention adopts an indexing device (indexing plate) design, which has the adaptability to multi-station welding. The position sensor set on the indexing plate can further verify the rotation angle of the disk to be welded, so that the blades of the whole bladed disk can be repeatedly indexed and quickly changed when welding blades one by one. It is easier to restore the same spatial position relationship after each rotation, improve the consistency of each blade welding station, reduce the time for repeated alignment and manual calibration, and improve production efficiency and clamping repeatability.

[0020] (5) The clamping fixture provided by the present invention has a hydraulic device of a clamping nut or a hydraulic pressure head. The hydraulic pressure head can further realize the precise adjustment and automated control of the clamping force, thereby improving the versatility and operability of the fixture. The fixture material and structural design take into account wear resistance and long-term service reliability, and meet the needs of mass production.

[0021] (6) The closed-loop control method provided by this invention covers the entire process from parameter preset, clamping and positioning, indexing and locking, multi-source data acquisition, threshold comparison, online adjustment, closed-loop monitoring of the welding process to post-weld release and data recording, realizing intelligent management of the clamping status during the welding process. The recorded data can be used for subsequent quality traceability and process parameter optimization, and is especially suitable for batch manufacturing scenarios. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the clamping fixture provided in Embodiment 1 of the present invention; Figure 2 for Figure 1 Partial sectional view; Figure 3 This is a schematic diagram of the mandrel structure of the clamping fixture provided in Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the base of the clamping fixture provided in Embodiment 1 of the present invention; Figure 5 This is a schematic diagram of the structure of the wheel to be welded; Figure 6 This is a schematic diagram of the clamping fixture provided in Embodiment 2 of the present invention; Figure 7 This is a flowchart of the closed-loop control method of the present invention.

[0023] Explanation of reference numerals in the attached drawings: 1. Clamping device; 11. Pressure sensor; 12. First tightening hydraulic sleeve; 13. Clamping nut; 14. Hydraulic pressure head; 2. Wheel to be welded; 21. Center hole; 3. Mandrel; 31. Mandrel bolt; 32. Screw hole; 4. Indexing device; 41. Indexing plate; 42. Second tightening hydraulic sleeve; 43. Indexing device fixing nut; 44. Bolt; 5. Base; 51. Base bolt; 52. Cylindrical shaft; 6. Worktable. Detailed Implementation

[0024] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of the present invention by way of example, but should not be used to limit the scope of the present invention. That is, the present invention is not limited to the described preferred embodiments, and the scope of the present invention is defined by the claims.

[0025] In the description of this invention, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance; those skilled in the art can understand the specific meaning of the above terms in this invention as appropriate.

[0026] The prior art terms involved in this invention are: Linear friction welding: a solid-state welding technology that generates heat through high-frequency linear reciprocating friction between workpieces to be welded, bringing the interface material to a thermoplastic state, and then applying upsetting force to achieve connection.

[0027] Expansion hydraulic sleeve: A clamping element that uses hydraulic pressure to radially expand an elastic sleeve, used to achieve uniform radial clamping of hole-type parts.

[0028] Indexing plate: A mechanism used to position workpieces at certain angular intervals in the circumferential direction, enabling multi-station processing.

[0029] Example 1 like Figure 1 and Figure 2 As shown, this embodiment provides a clamping fixture for linear friction welding discs, which includes a clamping device 1, a mandrel 3, an indexing device 4, a base 5, and a worktable 6. The base 5 is mounted on the worktable 6. Figure 4As shown, the base 5 has fixing holes at its bottom and is fixedly connected to the worktable 6 by base bolts 51. The upper part of the base 5 has an inclined surface, and a cylindrical shaft 52 is arranged perpendicular to this inclined surface for positioning in conjunction with the indexing device 4. Specifically, the base can adopt an integral high-rigidity structure, and metal-rubber damping pads or composite damping pads are provided on the bottom surface in contact with the worktable 6 or the support surface of the indexing plate to absorb high-frequency vibrations transmitted to the base from the equipment and wheel during the welding process.

[0030] The indexing device 4 includes an indexing plate 41, a second tightening hydraulic sleeve 42, an indexing device fixing nut 43, bolts 44, and an angle encoder (not shown in the figure). The bottom of the indexing plate 41 has a blind hole that engages with the cylindrical shaft 52 for positioning. The second tightening hydraulic sleeve 42 is placed between the two for tightening connection, thus achieving the tightening and fixing of the indexing plate 41 and the base 5. The indexing device fixing nut 43 and bolts 44 are used to lock the relative position of the indexing plate 41 and the base 5. The indexing device 4 is used to drive the welding disc 2 to perform indexing and positioning in the circumferential direction to adapt to multi-station welding requirements. A position sensor is installed on the indexing plate to further verify the rotation angle of the welding disc, enabling repeated indexing and rapid repositioning when welding blades one by one on the overall bladed disk. Furthermore, the indexing device 4 is equipped with an angle encoder. The single rotation angle of the indexing device is set to 360° / N according to the number of blades N of the welding disc. When the angle detection value exceeds the preset allowable error, the control unit issues an alarm signal and prohibits the welding equipment from entering the welding program.

[0031] The mandrel 3 is mounted on the indexing device 4. One end of the mandrel 3 is connected to the center of the indexing device 4 to position the workpiece and ensure the tilt angle and position of the welding disc 2. The other end of the mandrel 3 is inserted into the center hole 21 of the welding disc 2, and the lower surface of the welding disc 2 contacts the upper surface of the mandrel 3. Specifically, as shown... Figure 3 As shown, the mandrel 3 is a stepped shaft, divided into a lower large-diameter section and an upper small-diameter section. Both the lower large-diameter section and the upper small-diameter section are cylindrical and are integrally formed. The large-diameter section has six screw holes 32, which are fixedly connected to the indexing device 4 (indexing plate 41) by mandrel bolts 31; one end of the small-diameter section is connected to the clamping device 1 and the wheel to be welded 2.

[0032] The first tightening hydraulic sleeve 12 is fitted onto the outer side of the upper small-diameter section of the mandrel 3, and is used to radially tighten the inner wall of the center hole of the wheel 2 to be welded, thereby fixing the wheel 2 to be welded onto the mandrel 3. The first tightening hydraulic sleeve 12 has an annular hollow structure with a hydraulic chamber inside and an oil inlet on the side wall. When hydraulic oil is injected, the first tightening hydraulic sleeve 12 expands radially, pressing against the inner wall of the center hole of the wheel 2 to be welded, thereby fixing the wheel 2 to be welded onto the mandrel 3. A sealing ring is provided between the inner hole of the first tightening hydraulic sleeve 12 and the mandrel 3.

[0033] In this embodiment, the clamping device 1 is a clamping nut 13, threadedly connected to the upper end of the mandrel 3. When the clamping nut 13 is tightened, its lower surface is pressed against the upper end face of the first expansion hydraulic sleeve 12 through the pressure sensor 11, thereby transmitting the axial force to the wheel 2 to be welded, achieving axial clamping of the end face. Specifically, the clamping nut 13 is positioned above the first expansion hydraulic sleeve 12 and the wheel 2 to be welded, and is threadedly connected to the upper end of the small-diameter section of the mandrel 3. The pressure sensor 11 is fixed to the lower surface of the clamping nut 13 and is in close contact with the upper surface of the first expansion hydraulic sleeve 12 or directly in close contact with the upper surface of the wheel 2 to be welded. When the clamping nut 13 is tightened, the pressure sensor 11 detects the axial clamping force in real time to ensure that the clamping force is within the preset range, avoiding wheel deformation due to excessive clamping force or unstable clamping due to insufficient clamping force.

[0034] The pressure sensor 11 is fixedly mounted on the lower surface of the clamping nut 13 to monitor the axial clamping force in real time. Its signal line is led out to the control unit through the wiring hole inside the spindle 3.

[0035] The control unit (e.g., a PLC or industrial computer) is connected to the indexing device 4 (including the hydraulic valve of the angle encoder and the second tightening hydraulic sleeve 42), the hydraulic valve of the first tightening hydraulic sleeve 12, the clamping nut 13 (not directly controlled, but can prompt the operator through torque or pressure signals), and the pressure sensor 11. In this embodiment, the control unit mainly performs data monitoring and alarm functions. The tightening of the clamping nut 13 is completed manually with the help of a torque wrench, but the value of the pressure sensor 11 can be displayed in real time to help the operator control the preload.

[0036] In addition, this embodiment also includes a temperature sensor and a vibration sensor. The temperature sensor is located near the mandrel 3 or the first tightening hydraulic sleeve 12, and the vibration sensor is located on the base 5. Both are connected to the control unit via signal.

[0037] The clamping device 1 clamps the wheel disc 2 to be welded through the cooperation of the clamping nut 13 and the first expansion hydraulic sleeve 12, thereby achieving a composite clamping of "center hole positioning + radial expansion + axial end face clamping". The mandrel 3 is inserted into the through hole of the first expansion hydraulic sleeve 12, and the clamping nut 13 is placed above the first expansion hydraulic sleeve 12, with its bottom surface in contact with the first expansion hydraulic sleeve 12 and the wheel disc 2 to be welded.

[0038] The first and second expansion hydraulic sleeves 12 and 42 can be made by adopting an annular hollow structure with an annular hydraulic cavity inside, which is filled with hydraulic oil and driven by a hydraulic system to expand radially.

[0039] Example 2 like Figure 6 As shown, the difference from Embodiment 1 is as follows: Replace the clamping nut 13 in the clamping device 1 with a hydraulic pressure head 14. The hydraulic pressure head 14 has a round cap-shaped structure with a threaded hole in the middle that mates with the mandrel 3. The hydraulic pressure head 14 is also equipped with a pressure adjustment structure and a pressure indicator. The clamping and loosening are controlled by the pressure adjustment structure, and the pressure indicator is used to display the current pressure status.

[0040] By using the first tightening hydraulic sleeve 12 and the hydraulic pressure head 14 together, the axial clamping force can be precisely adjusted and automatically controlled, which further improves the clamping accuracy and safety, and is especially suitable for welding process scenarios with higher requirements for clamping force control.

[0041] The various components of the clamping fixture of the present invention, especially the key load-bearing components such as the mandrel 3, the first tightening hydraulic sleeve 12, the clamping nut 13 or the hydraulic pressure head 14, are preferably made of high-strength alloy steel and undergo appropriate heat treatment to improve their fatigue resistance and wear resistance, so as to meet the service requirements of high-frequency vibration and large upsetting force during linear friction welding. At the same time, the structural design of the fixture takes into account the deformation coordination under the thermo-mechanical coupling effect, ensuring that a stable clamping state can be maintained during the welding thermal cycle.

[0042] A complete operational example of the closed-loop control method of the present invention, in conjunction with the above-described clamping fixture, is as follows: S1 Parameter Preset: Based on the material of the wheel 2 to be welded (e.g., titanium alloy TC4), diameter (Φ500mm), thickness (80mm), center hole diameter (Φ80mm), and linear friction welding process parameters (vibration frequency 120Hz, upsetting force 30kN), the operator presets the following parameters on the human-machine interface of the control unit: first tightening hydraulic sleeve pressure preset value P1=12MPa, second tightening hydraulic sleeve pressure preset value P2=8MPa, axial clamping force allowable range Fmin=15kN, Fmax=20kN, tooling temperature alarm threshold Tmax=80℃, indexing angle allowable error Δθ=±0.02°, vibration alarm threshold Amax=5g. After input confirmation, the control unit stores these parameters.

[0043] S2 Clamping and Positioning: The operator inserts the center hole of the wheel 2 to be welded into the upper small-diameter section of the mandrel 3, ensuring that the lower surface is in contact with the upper surface of the mandrel 3. The control unit issues a command to activate the hydraulic valve of the first tightening hydraulic sleeve 12, causing the first tightening hydraulic sleeve 12 to radially tighten until the pressure reaches P1=12MPa, then maintains the pressure. Then, the clamping nut 13 is manually or automatically tightened (or the hydraulic pressure head 14 is activated). The pressure sensor 11 displays the axial clamping force in real time, stopping when it reaches the range of 15-20kN.

[0044] S3 Indexing and Locking: Based on the number of blades to be welded, N=24, the control unit calculates a single rotation angle of 360° / 24=15°. It issues a command to the indexing device 4 to rotate the welding disc 2 to the 15° position. The angle encoder reads the angle value in real time. If the deviation is +0.015° (less than ±0.02°), the control unit allows the indexing device to lock; if the deviation is +0.03°, the control unit issues a correction command, driving the indexing device 4 to make a reverse fine adjustment of 0.03°. After passing the second inspection, it locks.

[0045] S4 Multi-source data acquisition: During the welding process, pressure sensor 11, temperature sensor, angle encoder, and vibration sensor synchronously acquire data at a sampling frequency of 100Hz and transmit it to the control unit.

[0046] S5 Data Judgment and Threshold Comparison: Real-time comparison by the control unit: The current value of the first tightening hydraulic sleeve pressure is 11.8MPa (normal), the axial clamping force is 16.5kN (normal), the temperature near the mandrel is 65℃ (<80℃), the indexing angle deviation is 0.01° (<0.02°), and the vibration amplitude is 3.2g (<5g). All are within the allowable range, and the control unit allows the welding program to continue.

[0047] S6 Online Adjustment and Compensation: If the axial clamping force drops to 14.5kN (below Fmin) during subsequent welding, the control unit immediately issues a command to activate the hydraulic station to replenish the pressure of the hydraulic head 14, restoring the pressure to 16kN. If the temperature rises to 85℃, the control unit activates the circulating cooling system to increase the cooling water flow. If the vibration amplitude exceeds 5g, the control unit issues an audible and visual alarm and suspends the welding procedure, awaiting operator inspection.

[0048] S7 Welding Process Closed-Loop Monitoring: Throughout the entire linear friction welding process (approximately 15 seconds), the control unit continuously performs the above monitoring and adjustment to ensure that the clamping force, temperature, and position remain within the set range. The control output is updated every 10 milliseconds.

[0049] S8 Post-weld release and data recording: After welding is completed, the control unit stops the welding interlock signal and sequentially releases the axial clamping (pressure relief), the first expansion hydraulic sleeve pressure relief (releasing radial expansion), and the indexing lock (loosening). At the same time, all pressure, temperature, angle, and vibration data during this welding process are packaged and stored, and a QR code is generated and attached to the workpiece record sheet for subsequent quality traceability and process optimization.

[0050] The clamping fixture and closed-loop control method proposed in this invention can be widely applied in the linear friction welding manufacturing of integral bladed disks for aero-engines, and is especially suitable for mass production applications requiring high welding quality and efficiency. This fixture can also be appropriately adjusted for friction welding and friction stir welding of other disc-shaped and cylindrical parts.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A clamping fixture for a wheel disc to be welded in linear friction welding, characterized in that, include: The base (5) is set on the workbench (6); The indexing device (4) includes an indexing plate (41), a second expansion hydraulic sleeve (42), and an angle encoder. The indexing plate (41) is radially expanded and connected to the base (5) through the second expansion hydraulic sleeve (42). The angle encoder is used to detect the indexing angle in real time. The mandrel (3) has its lower end fixedly connected to the center of the indexing device (4), and its upper end is used to pass through the center hole of the wheel disc (2) to be welded. The first expansion hydraulic sleeve (12) is sleeved on the outer side of the upper end of the mandrel (3) and is used to radially expand and tighten the inner wall of the center hole of the wheel disk (2) to be welded, so that the wheel disk (2) to be welded is fixed to the mandrel (3); A clamping device (1) is connected to the upper end of the mandrel (3) and is used to axially clamp the wheel disc (2) to be welded; A pressure sensor (11) is disposed between the clamping device (1) and the wheel disc to be welded (2) or the first expansion hydraulic sleeve (12) for real-time monitoring of axial clamping force and hydraulic expansion pressure; and The control unit is connected to the indexing device (4), the first tightening hydraulic sleeve (12), the second tightening hydraulic sleeve (42), the pressing device (1) and the pressure sensor (11) respectively, and is used to receive real-time data and perform closed-loop control.

2. The clamping fixture according to claim 1, characterized in that, The base (5) has an inclined surface on its upper part, and a cylindrical shaft (52) is arranged perpendicular to the inclined surface; the second expansion hydraulic sleeve (42) is sleeved on the outside of the cylindrical shaft (52) and is used to radially expand the blind hole provided at the bottom of the indexing plate (41), and the indexing plate (41) is locked to the base (5) by fixing the nut (43) and bolt (44) of the indexing device.

3. The clamping fixture according to claim 1, characterized in that, The mandrel (3) is a stepped shaft, including a large diameter section at the lower end and a small diameter section at the upper end. The wheel to be welded (2) is fixed to the small diameter section at the upper end. The large diameter section at the lower end is provided with multiple screw holes (32) for fixed connection with the indexing device (4) by mandrel bolts (31).

4. The clamping fixture according to claim 1, characterized in that, It also includes a temperature sensor and / or a vibration sensor; the temperature sensor is disposed on the mandrel (3), the first tightening hydraulic sleeve (12) or the clamping device (1) for monitoring the tooling temperature; the vibration sensor is disposed on the base (5) or the indexing device (4) for monitoring high-frequency vibration signals during the welding process; both the temperature sensor and the vibration sensor are signal connected to the control unit.

5. The clamping fixture according to claim 1, characterized in that, Metal rubber damping pads or composite damping pads are provided between the base (5) and the worktable (6) or / and between the indexing plate (41) and the wheel disc to be welded (2).

6. The clamping fixture according to claim 1, characterized in that, The clamping device (1) is a clamping nut (13), which is threaded to the upper end of the mandrel (3), and the lower surface of the wheel to be welded (2) is in contact with the upper surface of the mandrel (3).

7. The clamping fixture according to claim 1, characterized in that, The clamping device (1) is a hydraulic pressure head (14), which is located at the upper end of the mandrel (3) and is used to provide an adjustable axial clamping force.

8. The clamping fixture according to claim 7, characterized in that, The hydraulic head (14) has a round cap-shaped structure with a threaded hole in the middle that mates with the spindle (3). The hydraulic head (14) is also equipped with a pressure adjustment structure and a pressure indicator.

9. A closed-loop control method for a linear friction welding wheel clamping fixture with a central hole, characterized in that, The clamping fixture as described in any one of claims 1 to 8 comprises the following steps: S1 Parameter Preset: Based on the material, diameter, thickness, center hole size, and linear friction welding process parameters of the wheel to be welded, preset the pressure values ​​of the first and second tightening hydraulic sleeves, the allowable range of axial clamping force, the tooling temperature alarm threshold, the allowable error of the indexing angle, and the vibration alarm threshold, and input them into the control unit. S2 Clamping and Positioning: Install the wheel to be welded onto the mandrel, and insert the mandrel into the center hole of the wheel to be welded; activate the first expansion hydraulic sleeve to radially expand and position the center hole of the wheel to be welded, and at the same time, use the clamping device to axially clamp the end face of the wheel to be welded, thus completing the initial clamping; S3 Indexing Locking: The indexing device drives the welding wheel to rotate to the predetermined welding angle, and the angle encoder detects the current indexing angle in real time; when the deviation between the detected angle and the target angle is less than the preset allowable error, the indexing device locks; when the angle deviation exceeds the limit, the control unit issues a correction command to make the indexing device readjust its positioning. S4 Multi-source data acquisition: The pressure sensor acquires the axial clamping force and hydraulic expansion pressure in real time; the temperature sensor acquires the temperature near the mandrel, expansion hydraulic sleeve or clamping device in real time; the angle encoder acquires the indexing angle in real time; and the vibration sensor acquires the high-frequency vibration signal during the welding process and transmits the acquired data synchronously to the control unit. S5 Data Judgment and Threshold Comparison: The control unit compares the real-time collected pressure, temperature, angle and vibration data with preset thresholds to determine whether the pressure of the first tightening hydraulic sleeve, the pressure of the second tightening hydraulic sleeve, the axial clamping force, the tooling temperature, the indexing angle deviation and the vibration amplitude are within the allowable range. S6 Online Adjustment and Compensation: When the pressure is lower than the preset value, the control unit controls the hydraulic station to replenish the pressure; when the pressure is higher than the upper limit of allowable pressure, the control unit controls the hydraulic station to release pressure or stop pressurizing; when the temperature exceeds the set threshold, the circulating cooling system is started or the cooling flow is increased; when the indexing angle deviation exceeds the limit, the control unit controls the indexing device to make fine-tuning of the angle; when the vibration amplitude exceeds the set threshold, an alarm is issued and the welding program is paused. S7 Welding Process Closed-Loop Monitoring: During the linear friction welding process, the control unit continuously receives feedback signals from pressure sensors, temperature sensors, angle encoders and vibration sensors, and dynamically adjusts hydraulic pressure, cooling flow and indexing locking state according to real-time deviations to achieve stable clamping force, thermal deformation control and position accuracy maintenance during the welding process. S8 Post-weld release and data recording: After welding is completed, the control unit stops the welding interlock signal and releases the axial clamping, center hole expansion and indexing locking states in sequence; at the same time, the pressure, temperature, angle and vibration data during this welding process are recorded for subsequent quality traceability, process parameter optimization and batch welding consistency control.

10. The closed-loop control method according to claim 9, characterized in that, In step S6, when the angle detection value exceeds the preset allowable error, the control unit issues an alarm signal and prohibits the welding equipment from entering the welding program.

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