A metal parts strengthening device and method based on high-frequency pulse current

Abstract

The present invention provides a device and method for strengthening metal parts based on high-frequency pulse current. The device includes an axial tension and compression assembly, a detection and cooling assembly, a torque application assembly, a pulse power supply, a controller, and a frame. The structure is simple and reliable, and a servo motor is used in conjunction with a reducer to make the applied torque more precise and stable. At the same time, in conjunction with the pulse power supply, the current magnitude and frequency can be adjusted, and the axial tension and pressure are provided in conjunction with the lead screw, making the strengthening process of the parts more diverse and the strengthening effect better. The device refines the application method of axial tension and pressure through two sets of upper and lower linear modules, and can perform high-frequency pulse current strengthening on parts and specimens of different types, sizes, and shapes. The present invention also provides a new idea and method for material performance testing. During the strengthening process, torque and axial force can be applied to the parts to be strengthened to refine the internal grains, improve the lattice arrangement structure, and better improve the material performance.

Description

Technical Field

[0001] The present invention relates to the field of metal material strengthening, and in particular to a metal component strengthening device and method based on high-frequency pulse current. Background Art

[0002] With the advancement of metal material preparation and processing technology, the application of high-strength metals is becoming increasingly widespread. Some components are prone to fatigue damage after prolonged operation, ultimately reducing safety and service life. Consequently, a variety of metal strengthening technologies have been applied to these components. Pulse current strengthening, as a new strengthening technology, leverages its electroplastic effect to improve the plastic deformation capacity of components while also alleviating stress concentration, refining grains, and eliminating cracks. Currently, most metal component strengthening devices and methods rely on current-pass tests on small specimens. There is no dedicated current strengthening equipment, and the strengthening methods are relatively traditional. Furthermore, component shapes vary, from small specimens to large components. Existing devices use displacement devices to adjust the distance and perform tension and compression operations for components of varying sizes, resulting in inaccurate control of tension and compression forces. Therefore, it is necessary to develop an independent device that can not only adjust the frequency and magnitude of the current during the current strengthening process, but also apply torque and axial force to various specimens or large components. This allows for strengthening and testing the performance of metal components, providing more options for metal strengthening. Summary of the Invention

[0003] In order to solve the above technical problems, the present invention provides a metal component strengthening device based on high-frequency pulse current, comprising an axial tension and compression component, a detection and cooling component, a torque application component, a pulse power supply, a controller, and a frame; the axial tension and compression component, the detection and cooling component, and the torque application component are sequentially arranged on the same surface of the frame; the pulse power supply and the controller are arranged on the frame;

[0004] The axial tension and compression assembly includes a first linear module, a first support frame, a second linear module and a fixture disk. The first linear module is fixed to the frame, the first support frame is mounted on the slide of the first linear module, and the second linear module is mounted on the first support frame. The second linear module is connected to the fixture disk.

[0005] The detection and cooling component is arranged between the axial tension and compression component and the torque application component, and the detection and cooling component includes one or more of a visual camera, a temperature sensor and a cooling device;

[0006] The torque applying assembly includes a torque motor, a reducer, a second support frame and a torque chuck; the torque motor and the reducer are arranged on the second support frame, and the second support frame is fixed to the frame body; the output shaft of the torque motor is connected to the input shaft of the reducer; the output shaft of the reducer is coaxially connected to the torque chuck through a coupling;

[0007] The fixture disk of the axial tension and compression assembly is provided with several fixtures, each of which is provided with an electrode threaded connection hole, an insulating ring is provided on the inner ring of the electrode threaded connection hole, and a contact surface is reserved at the bottom; the pulse electrode is threadedly connected to the electrode threaded connection hole, and the bottom of the pulse electrode contacts the bottom of the electrode threaded connection hole; the torque chuck of the torque application assembly is provided with a corresponding pulse electrode; the pulse electrode is connected to the pulse power supply through a wire; the fixture and torque chuck are both made of good conductor materials;

[0008] The first linear module, the second linear module, the detection and cooling component, the torque motor and the pulse power supply are respectively connected to the controller.

[0009] Furthermore, the first linear module includes a module base plate, a first linear guide, a first ball screw, a first screw motor and a slide, and the first linear guide is fixed on the module base plate; both ends of the first ball screw are pivotally connected to the bearing seat provided on the module base plate, and the first ball screw is arranged parallel to the first linear guide; the first screw motor is provided on the module base plate, and the output shaft of the first screw motor is connected to one end of the first ball screw; the slide is provided on the first linear guide, and the slide is slidably connected to the first linear guide, and the first ball screw is threadedly connected to the threaded hole provided on the slide.

[0010] Furthermore, the sides of the module base plate are provided with limiting guide rails, and the sides of the slide are slidably connected to the limiting guide rails.

[0011] Furthermore, the second linear module includes a module sleeve, a threaded sleeve, a second ball screw and a second screw motor. The module sleeve is arranged on the first support frame, and the inner wall of the module sleeve is provided with an axial raised slide rail; one end of the threaded sleeve is provided with a flange, the inner wall of the threaded sleeve is provided with a thread, and the outer wall is provided with a slideway that cooperates with the raised slide rail. The threaded sleeve is inserted into the module sleeve and is slidably connected to the module sleeve; the threaded sleeve is connected to the clamp plate through the flange; one end of the second ball screw is connected to the output shaft of the second screw motor, and the other end extends into the threaded sleeve and is threadedly connected to the threaded sleeve; the second screw motor is arranged on the first support frame.

[0012] Furthermore, the second linear module also includes an axial force sensor, which is arranged between the output shaft of the second screw motor and the second ball screw; the axial force sensor is connected to the controller.

[0013] Furthermore, the clamp disk is provided with several clamp bases extending outward from the central axis, each clamp base is provided with a clamp guide rail extending outward from the central axis of the clamp disk, and each clamp guide rail is provided with a clamp; the clamp is slidably connected to the clamp guide rail through a clamp slide; the clamp slide is provided with a guide rail clamp; the clamp slide is eccentrically set, and when each clamp slides to the clamp guide rail close to the center position of the clamp disk, the clamp and the torque chuck of the torque application assembly are horizontally axially aligned; the clamp includes a three-jaw chuck, a four-jaw chuck, a vise or an extension tray; the clamp slide is made of insulating material.

[0014] Furthermore, the torque application assembly also includes a torque sensor, which is arranged on the second support frame. The input end of the torque sensor is connected to the output shaft of the reducer through a coupling, and the output end of the torque sensor is connected to the transmission shaft of the torque chuck through a coupling; the torque sensor is connected to the controller; a transmission shaft bracket is provided on the second support frame, and the transmission shaft of the torque chuck passes through the transmission shaft bracket and is pivotally connected to the transmission shaft bracket through a bearing.

[0015] Furthermore, the frame includes a profile frame, an upper table, an insulating plate, a lower table and a foot. The upper table is arranged on the upper part of the profile frame, and an insulating plate is provided between the upper table and the profile frame; the lower table is arranged on the lower part of the profile frame; the foot is arranged at the bottom of the profile frame; the axial tension and compression component, the detection and cooling component, and the torque application component are arranged on the upper table in sequence; the pulse power supply and the controller are arranged on the lower table.

[0016] Furthermore, a drainage trough is provided on the upper table, and a waste liquid collection container is provided at the end of the drainage trough; a drainage hole is opened on the module bottom plate of the first linear module, and the drainage hole is connected to the drainage trough of the upper table.

[0017] Using the above-mentioned metal component strengthening device based on high-frequency pulse current, the present invention also provides a metal component strengthening method based on high-frequency pulse current, comprising the following steps:

[0018] (1) Clamping the parts to be strengthened:

[0019] Select the appropriate fixture on the fixture plate in the axial tension and compression assembly according to the shape of the component;

[0020] For parts distributed axially along the central axis, the fixture is first pushed to the center of the fixture disk, horizontally axially aligned with the torque chuck of the torque application assembly, and the fixture slide is locked by the guide rail clamp to prevent eccentric pressure; then the controller controls the operation of the first screw motor of the first linear module in the axial tension and compression assembly, driving the axial tension and compression assembly to approach the torque application assembly until the fixture of the axial tension and compression assembly and the torque chuck of the torque application assembly jointly clamp the part;

[0021] For special-shaped parts with non-axial distribution, first fix one end of the part on the torque chuck of the torque application assembly, and push the clamp to the corresponding position on the clamp guide rail according to the position of the part's other end that is suitable for clamping, so that the clamp of the clamp disk is directly opposite to the part's other end that is suitable for clamping; then control the first screw motor of the first linear module in the axial tension and compression assembly through the controller to drive the axial tension and compression assembly to approach the torque application assembly until the clamp of the axial tension and compression assembly and the torque chuck of the torque application assembly jointly clamp the part; lock the clamp slide through the guide rail clamp.

[0022] (2) Connect the pulse power supply:

[0023] Connect a pulse electrode to the electrode threaded connection hole on the fixture of the axial tension and compression assembly, ensuring that the bottom of the pulse electrode is in full contact with the bottom of the electrode threaded connection hole; connect the two wires of the pulse power supply to the pulse electrode on the fixture and the pulse electrode on the torque chuck respectively;

[0024] (3) Pulse current enhancement:

[0025] Adjust the current size and frequency according to the strengthening needs, control the output of the pulse power supply through the controller, and provide high-frequency pulse current to the parts through the fixture of the axial tension and compression assembly and the torque chuck of the torque application assembly to start the pulse current strengthening operation on the parts; the pulse current frequency is 50-3000Hz, and the pulse current voltage is 5-25V;

[0026] (4) Apply axial tension:

[0027] The controller controls the operation of the second screw motor of the second linear module in the axial tension and compression assembly, converting the rotational motion into the linear motion of the threaded sleeve through the second ball screw. The threaded sleeve moves linearly back and forth within the module sleeve, and the axial tension and pressure are transmitted to the component through the fixture plate connected by the flange plate.

[0028] Considering the second ball screw and the second screw motor output shaft as rigid bodies, a transformation model between the second screw motor torque and axial force is established. Ignoring the deformation during the transmission process, we have:

[0029] x l =r g θ

[0030] Where: x l is the axial displacement of the threaded sleeve, r g is the second ball screw transmission ratio, θ is the angular displacement of the component to be strengthened;

[0031] The dynamic equation of the axial loading of the second linear module is expressed as:

[0032]

[0033] Where: J is the equivalent moment of inertia of the second ball screw, B is the equivalent viscous damping coefficient of the second linear module, T m is the output torque of the second screw motor, T d is the equivalent interference torque;

[0034] Performing Laplace transformation on the above equation yields the relationship between the output torque of the second screw motor and the linear displacement of the flange:

[0035]

[0036] Where: s is the Laplace operator, G(s) is the system transfer function;

[0037] The spatial state equation of the rigid body model is:

[0038]

[0039] y rigid =[1 0]x rigid

[0040] Where: x rigid is the state variable of the second linear module, y rigid Output of the second linear module, K a is the current amplifier gain, K t is the motor torque constant;

[0041] (5) Applied torque:

[0042] The controller controls the operation of the torque motor in the torque application assembly, which applies torque to the components through the reducer, coupling, torque sensor, torque chuck and other structures in sequence;

[0043] The torque output satisfies the following relationship:

[0044] The torque equation of the torque motor is abstracted as:

[0045] T e =N p (ψ d i q -ψ q i d )

[0046] Where: N p is the number of torque winding pole pairs, T e is the electromagnetic torque, ψ d , ψ q are the direct axis and quadrature axis magnetic flux components in the dq axis coordinate system, i q 、i dare the direct axis and quadrature axis current components in the dq axis coordinate system respectively;

[0047] After transformation:

[0048] T e =N e [ψ f i q +(L d -L q )i d i q ]

[0049] Where: f is the magnetic flux of the rotor permanent magnet, L d , L q is the direct-axis inductance and quadrature-axis inductance;

[0050] The electromagnetic torque equation is:

[0051]

[0052] Where: L md i f is the equivalent magnetic flux, β is the load angle, i s is the current vector;

[0053] Taking into account the motor salient pole effect, the electromagnetic torque equation is finally optimized as follows:

[0054] T e =N p L md i f i q

[0055] When the torque motor is in motion, the motion equation conforms to:

[0056]

[0057] Among them, T l is the load torque, J is the total moment of inertia, P is the differential operator, and B is the viscous friction coefficient. r is the motor speed;

[0058] (6) Monitoring cooling:

[0059] During the power-on strengthening process, the axial force applied is detected by the axial force sensor, and the torque applied is detected by the torque sensor;

[0060] The cooling component uses a visual camera to scan and photograph the surface of the reinforced component; the temperature of the component surface is measured and monitored by a temperature sensor; when the temperature exceeds the threshold, the component is cooled by a cooling device;

[0061] The data collected by the axial force sensor, torque sensor, and detection and cooling component are transmitted to the controller.

[0062] Beneficial effects of the present invention:

[0063] The present invention has built a set of independent pulse power supply strengthening devices with a simple and reliable structure. The use of a servo motor with a reducer makes the applied torque more accurate and stable. At the same time, in conjunction with an argon arc welding power supply, the current size and frequency can be adjusted, and the screw is used to provide axial pulling pressure, making the strengthening process of parts more diverse and the strengthening effect better. The device refines the application method of axial pulling pressure through two sets of upper and lower linear modules, and can perform high-frequency pulse current strengthening on parts and samples of different types, sizes, and shapes. At the same time, during the strengthening process, torque and axial force can be applied to the parts to be strengthened to refine the internal grains, improve the lattice arrangement mechanism, and better improve the material properties. The present invention also provides a new idea and method for material performance testing, which can achieve different degrees and different effects of strengthening of parts by changing the current frequency, current, torque, and axial force. The device and method of the present invention are suitable for research and testing of new materials and mechanical property testing of processed parts after strengthening. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0065] Figure 2 This is a schematic diagram of the structure of the axial tension and compression assembly of the present invention;

[0066] Figure 3 This is a schematic structural diagram of the first linear module of the present invention;

[0067] Figure 4 This is a schematic diagram of the structure of the second linear module of the present invention;

[0068] Figure 5 This is a schematic diagram of the structure of the clamping plate of the present invention;

[0069] Figure 6 This is a schematic diagram of the structure of the cooling component for detecting the present invention;

[0070] Figure 7 This is a schematic structural diagram of the torque applying assembly of the present invention;

[0071] Figure 8 This is a schematic diagram of the frame structure of the present invention;

[0072] 1. Axial tension and compression components;

[0073] 101, first linear module 102, first support frame 103, second linear module 104, fixture plate 105, pulse electrode 106, module base plate 107, first linear guide rail 108, first ball screw 109, first screw motor 110, slide 111, bearing seat 112, limit guide rail 113, module sleeve 114, threaded sleeve 115, second ball screw 116, second screw motor 117, raised slide rail 118, flange 119, axial force sensor 120, fixture base 121, fixture guide rail 122, three-jaw chuck 123, vise 124, extension tray 125, fixture slide;

[0074] 2. Detect cooling components;

[0075] 201, visual camera 202, infrared temperature sensor 203, universal joint nozzle;

[0076] 3. Torque application assembly;

[0077] 301, torque motor 302, reducer 303, second support frame 304, torque chuck 305, torque sensor 306, coupling 307, transmission shaft bracket;

[0078] 4. Pulse power supply;

[0079] 5. Controller;

[0080] 6. Frame;

[0081] 601, profile frame 602, upper table 603, insulation board 604, lower table 605, footing 606, drainage trough 607, waste liquid collection container. DETAILED DESCRIPTION

[0082] See Figure 1-8 As shown:

[0083] This embodiment provides a metal component strengthening device based on high-frequency pulse current, comprising an axial tension and compression assembly 1, a detection and cooling assembly 2, a torque application assembly 3, a pulse power supply 4, a controller 5, and a frame 6; the axial tension and compression assembly 1, the detection and cooling assembly 2, and the torque application assembly 3 are sequentially arranged on the same surface of the frame 6; the pulse power supply 4 and the controller 5 are arranged on the frame 6;

[0084] The axial tension and compression assembly 1 includes a first linear module 101, a first support frame 102, a second linear module 103 and a fixture disk 104. The first linear module 101 is fixed to the frame 6. The first support frame 102 is arranged on the slide 110 of the first linear module 101. An insulating plate or insulating gasket is provided between the first support frame 102 and the slide 110. The second linear module 103 is arranged on the first support frame 102. The second linear module 103 is connected to the fixture disk 104.

[0085] The detection and cooling component 2 is arranged between the axial tension and compression component 1 and the torque application component 3. The detection and cooling component 2 includes a visual camera 201, an infrared temperature sensor 202 and a universal joint nozzle 203. The universal joint nozzle 203 is connected to the spray pump and the liquid storage tank; the liquid storage tank stores cooling liquid, and the universal joint nozzle 203 sprays cooling liquid for cooling metal parts to avoid excessive temperature affecting the strengthening quality.

[0086] The torque application assembly 3 includes a torque motor 301, a reducer 302, a second support frame 303, a torque chuck 304 and a torque sensor 305; the torque motor 301 and the reducer 302 are arranged side by side on the second support frame 303, and the second support frame 303 is fixed on the frame body 6; the output shaft of the torque motor 301 is connected to the input shaft of the reducer 302; the output shaft of the reducer 302 is connected to the input end of the torque sensor 305 through a coupling 306, and the output end of the torque sensor 305 is connected to the transmission shaft of the torque chuck 304 through a coupling 306; the torque sensor 305 is arranged on the second support frame 303, and the torque sensor 305 is connected to the controller 5; a transmission shaft bracket 307 is provided on the second support frame 303, and the transmission shaft of the torque chuck 304 passes through the transmission shaft bracket 307 and is pivotally connected to the transmission shaft bracket 307 through a bearing.

[0087] The clamp disk 104 of the axial tension and compression component 1 is provided with several clamps, and the clamps are provided with electrode threaded connection holes, the inner ring of the electrode threaded connection holes is provided with an insulating ring, and a contact surface is reserved at the bottom; the pulse electrode 105 is threadedly connected to the electrode threaded connection hole, and the bottom of the pulse electrode 105 contacts the bottom of the electrode threaded connection hole. The threaded pulse electrode makes it more convenient to disassemble and assemble the electrode, and discharge is less likely to occur during the strengthening process; the torque chuck 304 of the torque applying component 3 is provided with a corresponding pulse electrode 105; the pulse electrode 105 is connected to the pulse power supply 4 through a wire; the clamp and the torque chuck 304 are both made of good conductor materials to achieve circuit closure and apply pulse current to metal parts.

[0088] The first linear module 101, the second linear module 103, the detection and cooling assembly 2, the torque motor 301, and the pulse power supply 4 are each connected to a controller 5. The pulse power supply 4 primarily provides high-frequency current for the pulse current metal strengthening device. The controller 5 adjusts the output frequency and value of the current. An alarm interface displays undervoltage and overvoltage conditions to ensure safe operation of the device. The controller 5 collects data signals collected by the detection and cooling assembly 2 and controls the operation of the first linear module 101, the second linear module 103, the detection and cooling assembly 2, the torque motor 301, and the pulse power supply 4.

[0089] Furthermore, the first linear module 101 includes a module base plate 106, a first linear guide rail 107, a first ball screw 108, a first screw motor 109 and a slide 110. The two first linear guide rails 107 are fixed in parallel on the module base plate 106; the two ends of the first ball screw 108 are pivotally connected to the bearing seat 111 provided on the module base plate 106, and the first ball screw 108 is arranged in parallel with the first linear guide rail 107. between; the first screw motor 109 is arranged at one end of the module base plate 106, and the output shaft of the first screw motor 109 is connected to one end of the first ball screw 108; the slide 110 is arranged on the first linear guide 107, the slide 110 is slidingly connected to the first linear guide 107, and the first ball screw 108 is threadedly connected to the threaded hole set at the bottom of the slide 110 to form a ball screw pair, which converts the rotational motion output by the first screw motor 109 into linear motion of the slide 110.

[0090] The side of the module bottom plate 106 is further provided with a limiting guide rail 112, and the side of the slide 110 is slidably connected to the limiting guide rail 112 to play a limiting role.

[0091] Furthermore, the second linear module 103 includes a module sleeve 113, a threaded sleeve 114, a second ball screw 115 and a second screw motor 116. The module sleeve 113 is arranged on the upper part of the first support frame 102, and the inner wall of the module sleeve 113 is provided with an axial raised slide rail 117; one end of the threaded sleeve 114 is provided with a flange 118, the inner wall of the threaded sleeve 114 is provided with a thread, and the outer wall is provided with a slideway that cooperates with the raised slide rail 117. The threaded sleeve 114 is inserted into the module sleeve 113 and is slidably connected to the module sleeve 113; the threaded sleeve 114 is connected to the clamp plate 104 through the flange 118; one end of the second ball screw 115 is connected to the output shaft of the second screw motor 116, and the other end extends into the threaded sleeve 114 and is threadedly connected to the threaded sleeve 114; the second screw motor 116 is arranged at one end of the first support frame 102.

[0092] The second linear module 103 further includes an axial force sensor 119 , which is disposed between the output shaft of the second screw motor 116 and the second ball screw 115 ; the axial force sensor 119 is connected to the controller 5 .

[0093] The fixture disk 104 is provided with three fixture bases 120 extending outward from the central axis, and each fixture base 120 is provided with a fixture guide rail 121 extending outward from the central axis of the fixture disk 104, and each fixture guide rail 121 is provided with a fixture; the fixture base 120 can be made of insulating material; the fixture includes a three-jaw chuck 122 or a four-jaw chuck, a vise 123 and an extension tray 124; the three-jaw chuck 122 is used to clamp columnar parts and hollow tubular parts, the vise 123 is used to clamp sheet and block parts, and the extension tray 124 is used to install other specific types of fixtures, expand the application range of fixture types and devices, and realize the clamping and quick replacement of various types of parts. Current enhancement is no longer limited to columnar parts, which greatly improves the versatility and convenience of equipment fixtures during current enhancement. The clamps are slidably connected to the clamp guide rail 121 via a clamp slide 125. A rail clamp is provided on the clamp slide 125. Because the clamp slide 125 cannot reach the center of the clamp plate 104, the clamps on the clamp slide 125 are eccentrically positioned, offset toward the center of the clamp plate 104. When each clamp slides to the end of the clamp guide rail 121 near the center of the clamp plate 104, the center of the clamp is horizontally aligned with the center of the torque chuck 304 of the torque application assembly 3. The clamp slide 125 is made of insulating material. The torque chuck 304 is a four-jaw chuck to ensure uniform force during torque application.

[0094] The frame 6 includes a profile frame 601, an upper table 602, an insulating plate 603, a lower table 604 and a foot 605. The upper table 602 is arranged on the upper part of the profile frame 601, and an insulating plate 603 is provided between the upper table 602 and the profile frame 601; the lower table 604 is arranged at the lower part of the profile frame 601; the foot 605 is arranged at the bottom of the profile frame 601; the axial tension and compression component 1, the detection and cooling component 2, and the torque application component 3 are arranged in sequence on the upper table 602; the pulse power supply 4 and the controller 5 are arranged on the lower table 604.

[0095] The upper table 602 is provided with a drainage trough 606, and a waste liquid collection container 607 is provided at the end of the drainage trough 606; a drainage hole is opened on the module base plate 106 of the first linear module 101, and the drainage hole is connected to the drainage trough 606 of the upper table 602. The cooling liquid flows through the drainage hole on the module base plate 106, through the drainage trough 606 of the upper table 602, and is collected in the waste liquid collection container 607.

[0096] The device in this embodiment measures 1500mm (L x W x H) x 700mm (H x W) x 600mm, making it compact and reliable. It can clamp components ranging in length from 0 to 800mm. The torque applied range is 0 to 1500N·m, and the axial load applied range is 0 to 2500N. The metal component to be strengthened is initially a solid metal sample or a pre-processed large metal component.

[0097] Using the above-mentioned metal component strengthening device based on high-frequency pulse current, this embodiment also provides a metal component strengthening method based on high-frequency pulse current, comprising the following steps:

[0098] (1) Clamping the parts to be strengthened:

[0099] Select the appropriate fixture on the fixture disk 104 in the axial tension and compression assembly 1 according to the shape of the component;

[0100] For components distributed axially along the central axis, the fixture is first pushed to the center of the fixture disk 104, horizontally axially aligned with the torque chuck 304 of the torque applying assembly 3, and the fixture slide 125 is locked by the guide rail clamp to prevent eccentric pressure; then the controller 5 controls the first screw motor 109 of the first linear module 101 in the axial tension and compression assembly 1 to operate, driving the axial tension and compression assembly 1 to approach the torque applying assembly 3, until the fixture of the axial tension and compression assembly 1 and the torque chuck 304 of the torque applying assembly 3 jointly clamp and fix the component;

[0101] For special-shaped parts with non-axial distribution, first fix one end of the part on the torque chuck 304 of the torque applying assembly 3, and push the clamp to the corresponding position on the clamp guide rail 121 according to the position of the part suitable for clamping at the other end, so that the clamp of the clamp disk 104 is directly opposite to the part suitable for clamping at the other end of the part; then control the first screw motor 109 of the first linear module 101 in the axial tension and compression assembly 1 to operate through the controller 5, driving the axial tension and compression assembly 1 to approach the torque applying assembly 3 until the clamp of the axial tension and compression assembly 1 and the torque chuck 304 of the torque applying assembly 3 jointly clamp the part; and lock the clamp slide 125 through the guide rail clamp.

[0102] (2) Connect the pulse power supply:

[0103] Connect a pulse electrode 105 to the electrode threaded connection hole on the fixture of the axial tension and compression assembly 1, ensuring that the bottom of the pulse electrode 105 is in full contact with the bottom of the electrode threaded connection hole; connect the two wires of the pulse power supply 4 to the pulse electrode 105 on the fixture and the pulse electrode 105 on the torque chuck 304 respectively;

[0104] (3) Pulse current enhancement:

[0105] The current magnitude and frequency are adjusted according to the strengthening needs. The output of the pulse power supply 4 is controlled by the controller 5. The high-frequency pulse current is provided to the component through the clamp of the axial tension and compression assembly 1 and the torque chuck 304 of the torque application assembly 3. The pulse current strengthening operation of the component begins. The pulse current frequency is 50-3000Hz, and the pulse current voltage is 5-25V.

[0106] (4) Apply axial tension:

[0107] The controller 5 controls the operation of the second screw motor 116 of the second linear module 103 in the axial tension and compression assembly 1. The second ball screw 115 converts the rotational motion into the linear motion of the threaded sleeve 114. The threaded sleeve 114 moves linearly back and forth within the module sleeve 113, and the clamping plate 104 connected by the flange 118 transmits the axial tension and compression to the component.

[0108] The second ball screw 115 and the output shaft of the second screw motor 116 are considered as rigid bodies, so as to establish a conversion model between the torque and the axial force of the second screw motor 116 and ignore the deformation during the transmission process. Then, we have:

[0109] x l =r g θ

[0110] Where: x l is the axial displacement of the threaded sleeve 114, r g is the transmission ratio of the second ball screw 115, and θ is the angular displacement of the component to be strengthened;

[0111] The dynamic equation of the axial loading of the second linear module 103 is expressed as:

[0112]

[0113] Where: J is the equivalent moment of inertia of the second ball screw 115, B is the equivalent viscous damping coefficient of the second linear module 103, T m The second screw motor 116 outputs torque, T d is the equivalent interference torque;

[0114] Performing Laplace transformation on the above equation yields the relationship between the output torque of the second screw motor 116 and the linear displacement of the flange 118:

[0115]

[0116] Where:

[0117] The spatial state equation of the rigid body model is:

[0118]

[0119] yrigid =[1 0]x rigid

[0120] Where: x rigid is the state variable of the second linear module 103, y rigid The output of the second linear module 103,

[0121] In this embodiment, the axial loading transmission ratio of the second linear module 103 is r g 3.183 m·rad -1 , K a K t 2.242Nm·V -1 , which can achieve fast and stable application of axial force.

[0122] (5) Applied torque:

[0123] The controller 5 controls the operation of the torque motor 301 in the torque applying assembly 3, and applies torque to the component through the reducer 302, coupling 306, torque sensor 305 and torque chuck 304 in sequence;

[0124] The torque output satisfies the following relationship:

[0125] The torque equation of the torque motor 301 is abstracted as:

[0126] T e =N p (ψ d i q -ψ q i d )

[0127] Where: N p is the number of torque winding pole pairs,

[0128] After transformation:

[0129] T e =N e [ψ f i q +(L d -L q )i d i q ]

[0130] Where:

[0131] The electromagnetic torque equation is:

[0132]

[0133] Where: L md i f is the equivalent magnetic flux,

[0134] Taking into account the motor salient pole effect, the electromagnetic torque equation is finally optimized as follows:

[0135] T e =N p L md i f i q

[0136] During the motion of the torque motor 301, the motion equation conforms to:

[0137]

[0138] Among them, T l is the load torque, J is the total moment of inertia, P is the differential operator, and B is the viscous friction coefficient.

[0139] (6) Monitoring cooling:

[0140] During the power-on strengthening process, the axial force applied is detected by the axial force sensor 119, and the torque applied is detected by the torque sensor 305;

[0141] The detection and cooling component 2 scans and photographs the surface of the reinforced component through the visual camera 201; measures and monitors the surface temperature of the component through the infrared temperature sensor 202; and cools the component through the universal joint nozzle 203 when the temperature exceeds the threshold;

[0142] The data collected by the axial force sensor 119 , the torque sensor 305 , and the detection and cooling component 2 are transmitted to the controller 5 .

Claims

1. A method for strengthening metal parts based on high-frequency pulse current, characterized in that: A metal parts strengthening device based on high-frequency pulse current is used, which includes an axial tension and compression component, a detection and cooling component, a torque application component, a pulse power supply, a controller, and a frame; the axial tension and compression component, the detection and cooling component, and the torque application component are sequentially arranged on the same surface of the frame; the pulse power supply and the controller are arranged on the frame; The axial tension and compression assembly includes a first linear module, a first support frame, a second linear module and a fixture disk. The first linear module is fixed to the frame, the first support frame is mounted on the slide of the first linear module, and the second linear module is mounted on the first support frame. The second linear module is connected to the fixture disk. The first linear module includes a module base plate, a first linear guide, a first ball screw, a first screw motor and a slide, wherein the first linear guide is fixed to the module base plate; both ends of the first ball screw are pivotally connected to the bearing seat provided on the module base plate, and the first ball screw is arranged in parallel with the first linear guide; the first screw motor is provided on the module base plate, and the output shaft of the first screw motor is connected to one end of the first ball screw; the slide is provided on the first linear guide, the slide is slidably connected to the first linear guide, and the first ball screw is threadedly connected to the threaded hole provided on the slide; The second linear module includes a module sleeve, a threaded sleeve, a second ball screw and a second screw motor. The module sleeve is arranged on the first support frame, and the inner wall of the module sleeve is provided with an axial raised slide rail; one end of the threaded sleeve is provided with a flange, the inner wall of the threaded sleeve is provided with a thread, and the outer wall is provided with a slideway that cooperates with the raised slide rail. The threaded sleeve is inserted into the module sleeve and is slidably connected to the module sleeve; the threaded sleeve is connected to the fixture plate through the flange; one end of the second ball screw is connected to the output shaft of the second screw motor, and the other end extends into the threaded sleeve and is threadedly connected to the threaded sleeve; The second screw motor is arranged on the first support frame; The detection and cooling component is arranged between the axial tension and compression component and the torque application component, and the detection and cooling component includes one or more of a visual camera, a temperature sensor and a cooling device; The torque applying assembly includes a torque motor, a reducer, a second support frame and a torque chuck; the torque motor and the reducer are arranged on the second support frame, and the second support frame is fixed to the frame body; the output shaft of the torque motor is connected to the input shaft of the reducer; the output shaft of the reducer is coaxially connected to the torque chuck through a coupling; The fixture disk of the axial tension and compression assembly is provided with several fixtures, each of which is provided with an electrode threaded connection hole, an insulating ring is provided in the inner ring of the electrode threaded connection hole, and a contact surface is reserved at the bottom; the pulse electrode is threadedly connected to the electrode threaded connection hole, and the bottom of the pulse electrode contacts the bottom of the electrode threaded connection hole; the torque chuck of the torque application assembly is provided with a corresponding pulse electrode; The pulse electrode is connected to the pulse power supply through a wire; the clamp and torque chuck are made of good conductor materials; The first linear module, the second linear module, the detection and cooling component, the torque motor and the pulse power supply are respectively connected to the controller; The method comprises the following steps: (1) Clamping the parts to be strengthened: Select the appropriate fixture on the fixture plate in the axial tension and compression assembly according to the shape of the component; For parts distributed axially along the central axis, the fixture is first pushed to the center of the fixture disk, horizontally axially aligned with the torque chuck of the torque application assembly, and the fixture slide is locked by the guide rail clamp to prevent eccentric pressure; then the controller controls the operation of the first screw motor of the first linear module in the axial tension and compression assembly, driving the axial tension and compression assembly to approach the torque application assembly until the fixture of the axial tension and compression assembly and the torque chuck of the torque application assembly jointly clamp the part; For special-shaped parts with non-axial distribution, first fix one end of the part on the torque chuck of the torque applying assembly, and push the clamp to the corresponding position on the clamp guide rail according to the position of the part's other end that is suitable for clamping, so that the clamp of the clamp disk is aligned with the part's other end that is suitable for clamping; then, the controller controls the operation of the first screw motor of the first linear module in the axial tension and compression assembly, driving the axial tension and compression assembly to approach the torque applying assembly, until the clamp of the axial tension and compression assembly and the torque chuck of the torque applying assembly jointly clamp and fix the part; and lock the clamp slide by the guide rail clamp; (2) Connect the pulse power supply: Connect a pulse electrode to the electrode threaded connection hole on the fixture of the axial tension and compression assembly, ensuring that the bottom of the pulse electrode is in full contact with the bottom of the electrode threaded connection hole; connect the two wires of the pulse power supply to the pulse electrode on the fixture and the pulse electrode on the torque chuck respectively; (3) Pulse current enhancement: Adjust the current size and frequency according to the strengthening needs, control the output of the pulse power supply through the controller, and provide high-frequency pulse current to the parts through the fixture of the axial tension and compression assembly and the torque chuck of the torque application assembly to start the pulse current strengthening operation on the parts; the pulse current frequency is 50-3000Hz, and the pulse current voltage is 5-25V; (4) Apply axial tension: The controller controls the operation of the second screw motor of the second linear module in the axial tension and compression assembly, converting the rotational motion into the linear motion of the threaded sleeve through the second ball screw. The threaded sleeve moves linearly back and forth within the module sleeve, and the axial tension and pressure are transmitted to the component through the fixture plate connected by the flange plate. Considering the second ball screw and the second screw motor output shaft as rigid bodies, a transformation model between the second screw motor torque and axial force is established. Ignoring the deformation during the transmission process, we have: ， Where: is the axial displacement of the threaded sleeve, is the second ball screw transmission ratio, is the displacement of the corner of the component to be strengthened; The dynamic equation of the axial loading of the second linear module is expressed as: ， Where: is the equivalent moment of inertia of the second ball screw, is the equivalent viscous damping coefficient of the second linear module, Output torque for the second screw motor, is the equivalent interference torque; Performing Laplace transformation on the above equation yields the relationship between the output torque of the second screw motor and the linear displacement of the flange: ， Where: is the Laplace operator, is the system transfer function; The spatial state equation of the rigid body model is: ， Where: is the state variable of the second linear module, Output of the second linear module, ; is the current amplifier gain, is the motor torque constant; (5) Apply torque: The controller controls the operation of the torque motor in the torque application assembly, and applies torque to the component through the reducer, coupling, torque sensor and torque chuck structure in sequence; The torque output satisfies the following relationship: The torque equation of the torque motor is abstracted as: ， Where: is the number of torque winding pole pairs, is the electromagnetic torque, 、 They are The direct and quadrature axis flux components in the axis coordinate system, 、 They are Direct axis and quadrature axis current components in the axis coordinate system; After transformation: ， Where: is the magnetic flux of the rotor permanent magnet, 、 is the direct-axis inductance and quadrature-axis inductance; The electromagnetic torque equation is: ， Where: is the equivalent magnetic flux, is the load angle, is the current vector; Taking into account the motor salient pole effect, the electromagnetic torque equation is finally optimized as follows: ， When the torque motor is in motion, the motion equation conforms to: ， in, is the load torque, is the total moment of inertia, is the differential operator, is the viscous friction coefficient; is the motor speed; (6) Monitoring cooling: During the power-on strengthening process, the axial force applied is detected by the axial force sensor, and the torque applied is detected by the torque sensor; The cooling component uses a visual camera to scan and photograph the surface of the reinforced component; the temperature of the component surface is measured and monitored by a temperature sensor; when the temperature exceeds the threshold, the component is cooled by a cooling device; The data collected by the axial force sensor, torque sensor, and detection and cooling component are transmitted to the controller.

2. The method for strengthening metal parts based on high-frequency pulse current according to claim 1, characterized in that: The sides of the module bottom plate are further provided with limiting guide rails, and the sides of the slide are slidably connected to the limiting guide rails.

3. The method for strengthening metal parts based on high-frequency pulse current according to claim 1, characterized in that: The axial force sensor is arranged between the output shaft of the second screw motor and the second ball screw; the axial force sensor is connected to the controller.

4. The method for strengthening metal parts based on high-frequency pulse current according to claim 1, characterized in that: The clamp disk is provided with several clamp bases extending outward from the central axis, each clamp base is provided with a clamp guide rail extending outward from the central axis of the clamp disk, and each clamp guide rail is provided with a clamp; the clamp is slidably connected to the clamp guide rail through a clamp slide; the clamp slide is provided with a guide rail clamp; the clamp slide is eccentrically set, and when each clamp slides to the position where the clamp guide rail is close to the center of the clamp disk, the clamp and the torque chuck of the torque application assembly are horizontally axially aligned; the clamp includes a three-jaw chuck, a four-jaw chuck, a vise or an extension tray; the clamp slide is made of insulating material.

5. The method for strengthening metal parts based on high-frequency pulse current according to claim 1, characterized in that: The torque sensor is arranged on the second support frame, the input end of the torque sensor is connected to the output shaft of the reducer through a coupling, and the output end of the torque sensor is connected to the transmission shaft of the torque chuck through a coupling; the torque sensor is connected to the controller; a transmission shaft bracket is provided on the second support frame, the transmission shaft of the torque chuck passes through the transmission shaft bracket, and is pivotally connected to the transmission shaft bracket through a bearing.

6. The method for strengthening metal parts based on high-frequency pulse current according to claim 1, characterized in that: The frame includes a profile frame, an upper table, an insulating plate, a lower table and a foot. The upper table is arranged on the upper part of the profile frame, and an insulating plate is provided between the upper table and the profile frame; the lower table is arranged on the lower part of the profile frame; the foot is arranged at the bottom of the profile frame; the axial tension and compression assembly, the detection and cooling assembly, and the torque application assembly are arranged on the upper table in sequence; the pulse power supply and the controller are arranged on the lower table.

7. The method for strengthening metal parts based on high-frequency pulse current according to claim 6, characterized in that: The upper table is provided with a drainage trough, and a waste liquid collection container is provided at the end of the drainage trough; a drainage hole is opened on the module bottom plate of the first linear module, and the drainage hole is connected to the drainage trough of the upper table.

Images