A magnetic resistance type dynamic hole cold extrusion device

Abstract

This invention belongs to the field of machining technology and relates to a magnetic reluctance type dynamic hole cold extrusion device. It includes a housing with a magnetic loading assembly, which includes a support guide rail assembly on the housing. A cylindrical shot guide rail is mounted on the support guide rail assembly, and a coil is fitted onto the shot guide rail. A shot is fitted inside the shot guide rail. A mandrel assembly is located inside the housing on one side of the shot guide rail. The mandrel assembly includes a detachably connected boss mandrel and a non-boss mandrel. The end of the boss mandrel is used to connect to a mandrel. A guide buffer assembly includes a first mass block inside the housing. One end of the first mass block is connected to the shot, and the other end of the first mass block is connected to the end of the non-boss mandrel. At least one buffer block is provided on the first mass block, located near the shot. A limiting ring is fitted on the shot guide rail and is used to match the buffer block to achieve limiting. Using this invention, the mandrel is easy to disassemble, the surface quality is high, and the working efficiency is high.

Description

Technical Field

[0001] This invention belongs to the field of machining technology, specifically relating to a magnetic reluctance type dynamic hole cold extrusion device. Background Technology

[0002] Cold extrusion strengthening technology has been developed since the mid-to-late 20th century. In traditional applications, cold extrusion processes are mostly achieved using hydraulic transmission, pneumatic technology, or electric technology. The extrusion speed is slow, resulting in high costs, low overall efficiency, and obvious process defects in the products, such as excessive extrusion resistance, uneven residual stress, and possible stick jamming.

[0003] In subsequent research, the literature "A dynamic cold expansion method to improve fatigue performance of holed structures based on electromagnetic load" classified the traditional hole strengthening process with slow extrusion speed as static and the hole strengthening process with high-speed extrusion as dynamic. It studied the strengthening effect of dynamic cold extrusion. The results showed that the extrusion resistance generated by the dynamic cold extrusion strengthening process is about one-third of that of static cold extrusion. It generates higher and more uniform residual compressive stress and has better fatigue performance. Therefore, high-speed hole cold extrusion can solve the shortcomings of traditional hole cold extrusion.

[0004] Currently, high-speed cold extrusion devices based on electromagnetic force are used to achieve dynamic cold extrusion strengthening of holes. These devices utilize electromagnetic loading to achieve dynamic cold extrusion of holes, offering advantages such as high speed, good controllability, and high repeatability. However, precise control of the working stroke is difficult, leading to potential damage to the product surface. For example, patent application number 201910510340.1 discloses a high-speed cold extrusion device based on electromagnetic force loading, employing a magnetic loading device. The electromagnetic force generated by the loading device drives the mandrel to pass through the hole to be strengthened at high speed, achieving cold extrusion strengthening. However, this technology uses a pressing method for hole cold extrusion strengthening. Due to the inability to precisely control the working stroke, it can impact the surface of the specimen, causing damage. Furthermore, the mandrel is difficult to disassemble after use, resulting in low work efficiency. Summary of the Invention

[0005] In view of this, the present invention provides a magnetoresistive dynamic hole cold extrusion device. By implementing a mandrel pulling method with controllable stroke, dynamic cold extrusion of holes is achieved. The device is simple to operate, safe, and avoids impact on the specimen surface causing damage. It achieves the beneficial effects of simultaneously improving cold extrusion strengthening quality and efficiency. Furthermore, compared to magnetic induction loading devices, the magnetoresistive loading device can generate higher electromagnetic force under the same voltage, thus completing the high-speed loading required for dynamic cold extrusion of holes. After use, the mandrel is easy to disassemble, resulting in high surface quality and high working efficiency.

[0006] The technical solution of this invention is:

[0007] A reluctance-type dynamic hole cold extrusion device includes a housing, one end of which is fitted with a conical top cover. The top cover has a through hole forming a channel for mandrel drawing motion. The device is characterized by having a reluctance-type magnetic loading assembly inside the housing. The magnetic loading assembly includes a support rail assembly mounted on the housing, a cylindrical shot guide rail mounted on the support rail assembly, a coil mounted on the shot guide rail, and a shot mounted inside the shot guide rail. The coil generates a driving force to move the shot away from the top cover. The housing also includes a mandrel assembly located on one side of the shot guide rail. The mandrel assembly includes a detachably connected boss mandrel and a bossless mandrel. The end of the boss mandrel is used to connect to the mandrel. The device further includes:

[0008] A guide buffer assembly includes a first mass block disposed within the housing, located between the projectile guide rail and the top cover. One end of the first mass block is connected to the projectile, and the other end of the first mass block is connected to the end of the bossless mandrel. At least one buffer block is disposed on the first mass block, and the buffer block is located on the side close to the projectile.

[0009] The limiting ring is fitted onto the projectile guide rail and is used to match the buffer block to achieve limiting.

[0010] Preferably, the first mass block includes a cylinder, one side of which is coaxially provided with a mounting hole, which is threadedly connected to the bossless mandrel, and the other side of which is coaxially provided with a threaded shaft, one end of which is fixedly connected to the cylinder, and the other end of which is threadedly connected to a shot.

[0011] Preferably, the projectile guide rail includes a cylindrical body, the projectile is fitted inside the cylindrical body, a flange is coaxially fixed at one end of the cylindrical body, and a ballistic stop block is fitted inside the other end of the cylindrical body. The ballistic stop block is located on the side close to the first mass block to prevent the projectile from slipping out of the cylindrical body. A threaded section is provided on the outer wall of the cylindrical body. An elastic baffle and a washer are fitted and fixed on the cylindrical body. The elastic baffle and the washer are located on both sides of the coil, and the elastic baffle is located on the side close to the limiting ring.

[0012] Preferably, the flange has multiple grooves on the side away from the coil, and one end of the damper, the first buffer spring and the second buffer spring are respectively fixed in the multiple grooves, and the other end of the damper, the first buffer spring and the second buffer spring are respectively fixed to the housing.

[0013] Preferably, a second mass block and a third mass block are disposed between the top cover and the first mass block. The second mass block and the third mass block are fitted and fixed inside the housing. The second mass block is located on the side close to the first mass block. The boss mandrel and the non-boob mandrel pass through the second mass block and the third mass block.

[0014] Preferably, a buffer structure is provided between the first mass block and the second mass block. The buffer structure includes a plurality of buffer blocks 2 symmetrically arranged on the second mass block. The plurality of buffer blocks 2 are located on the side close to the first mass block. The second mass block is also provided with a plurality of buffer elastic members. The two ends of the elastic members are respectively connected to the first mass block and the second mass block.

[0015] Preferably, the limiting ring includes a ring body, the inner wall of the ring body is provided with an internal thread, the internal thread is threadedly connected to the threaded section on the cylinder body, and the outer wall of the ring body is provided with a plurality of limiting holes, the center line of the limiting holes is perpendicular to the center line of the ring body, and the limiting holes are used to insert connecting parts to fix the position of the ring body.

[0016] Preferably, a safety stop is coaxially arranged on the side of the third mass block away from the second mass block, and the boss mandrel passes through the safety stop. The end of the boss mandrel used to connect with the mandrel is provided with an annular boss. The safety stop and the boss work together to stop and buffer.

[0017] Preferably, a linear bearing is provided between the third mass block and the boss mandrel, or between the third mass block and the non-boob mandrel.

[0018] Preferably, the supporting guide rail assembly includes a first guide rail and a second guide rail that are fixed to the housing in sequence. The first guide rail and the second guide rail are arranged at intervals, and the second guide rail is located on the side closer to the first mass block. The second guide rail is in contact with the outer wall of the ring body, and the first guide rail is in contact with the elastic baffle and the washer.

[0019] Compared with existing technologies, the present invention provides a magnetoresistive dynamic hole cold extrusion device that achieves dynamic cold extrusion of holes by realizing a mandrel pull-out method with controllable stroke. This solves the problems of existing devices impacting the specimen surface, inability to control stroke, and difficulty in disassembling the mandrel. When using the present invention, the mandrel has already passed through the opening of the specimen before extrusion, thus achieving high positioning accuracy and avoiding radial deviation. The limiting ring can select the required stroke and is fixed at a designated position. During operation, the limiting ring and the guide buffer assembly restrict the travel distance of the projectile, achieving limiting. The damper, the first buffer spring, and the second buffer spring connected to the flange of the projectile guide rail are connected to the shell, which can withstand and reduce the high-speed impact during the high-speed cold extrusion of the hole. Multiple buffer elastic elements and the buffer block on the second mass block absorb the redundant energy during rebound. In addition, after extrusion, the mandrel is completely separated from the specimen, avoiding damage to the surface of the open-hole specimen caused by pulling the mandrel. At the same time, it is easy to disassemble the mandrel, simple to operate, and safe. It achieves the beneficial effect of simultaneously balancing the quality and efficiency of cold extrusion strengthening. Meanwhile, compared with magnetic induction loading devices, magnetoresistive loading devices can generate higher electromagnetic force under the same voltage, thereby completing the high-speed loading required for dynamic cold extrusion of holes. They have high energy conversion efficiency, strong practicality, and are worth promoting. Attached Figure Description

[0020] Figure 1 This describes the working principle and driving circuit of the present invention.

[0021] Figure 2 This is a schematic diagram of the structure of the present invention.

[0022] Figure 3 This is a schematic diagram of the structure of the first safety component used in the implementation of the present invention.

[0023] Figure 4 This is a schematic diagram of the structure of the second safety component used in the implementation of the present invention.

[0024] Figure 5 This is a schematic diagram illustrating the structure of the limiting ring used in the implementation of the present invention.

[0025] Figure 6 This is a schematic diagram of the working state of the present invention.

[0026] Figure label:

[0027] 1-Mandrel, 2-Top cover, 3-Shell, 4-Third mass block, 5-Second mass block, 6-First mass block, 7-Ballistic stop, 8-Projectile, 9-Limiting ring, 10-Set screw, 11-Baffle, 12-Coil, 13-Washer, 14-Projectile guide rail, 15-Damper, 16-Guide rail one, 17-Guide rail two, 18-Buffer block, 19-Mandrel without boss, 20-Linear bearing, 21-Safety stop, 22-Mandrel with boss, 23-First buffer spring, 24-Second buffer spring, 25-Third buffer spring, 26-Fourth buffer spring, 27-Fifth buffer spring, 28-Opening test piece. Detailed Implementation

[0028] This invention provides a magnetic reluctance type dynamic hole cold extrusion device, which is described below in conjunction with... Figures 1 to 6 The present invention is illustrated by the structural diagram shown below.

[0029] Example 1

[0030] like Figure 6 The cold extrusion apparatus shown utilizes a projectile 8 to drive the movement of a mandrel 1, allowing the excessively large-diameter mandrel 1 to pass through the hole in the perforated specimen 28, thereby achieving the purpose of strengthening. The schematic diagram of the principle driving the projectile 8 is shown below. Figure 1 As shown, C is the energy storage capacitor, S is the discharge trigger switch, R is the drive system resistor, and the projectile 8 is made of iron alloy. First, the energy storage capacitor is charged using a charger. When the set voltage value is reached, charging stops, and a trigger signal is sent to the trigger switch, causing the coil 12 circuit to conduct. The energy storage capacitor C discharges instantaneously, generating a large pulse current in the coil 12 and exciting a pulse magnetic field. This generates a magnetizing current on the projectile 8, producing a rightward attractive force. Furthermore, the magnetic reluctance in the magnetic circuit changes after the coil 12 is energized. According to the principles of magnetic flux conservation and energy conservation, the projectile 8 is continuously subjected to a rightward electromagnetic force before reaching the center of the coil, causing it to accelerate continuously.

[0031] This invention provides a magnetic reluctance type dynamic hole cold extrusion device, such as... Figure 2 As shown, it includes a core rod 1, a top cover 2, a housing 3, a third mass block 4, a second mass block 5, a first mass block 6, a ballistic stop block 7, a projectile 8, a limiting ring 9, a set screw 10, an elastic baffle 11, a coil 12, a washer 13, a projectile guide rail 14, a damper 15, a guide rail one 16, a guide rail two 17, a buffer block 18, a bossless mandrel 19, a linear bearing 20, a safety stop block 21, a bossed mandrel 22, a first buffer spring 23, a second buffer spring 24, a third buffer spring 25, a fourth buffer spring 26, a fifth buffer spring 27, and an open-hole specimen 28.

[0032] The housing 3 is a cylindrical structure, closed at one end and with internal threads at the other end. The top cover 2 is conical, with a through hole at one end forming a channel for the pulling motion of the mandrel 1. The other end of the top cover 2 is threaded externally, and the top cover 2 is threadedly connected to the internal threads on the housing 3. A magnetic loading assembly is installed inside the housing 3, and the magnetic loading assembly is a magnetoresistive structure.

[0033] The reluctance-type loading device consists of a solenoid coil 12 and a ferromagnetic projectile 8. A large pulsed current is generated in the coil 12, exciting a pulsed magnetic field. This results in a magnetizing current on the projectile 8, generating an attractive force. Simultaneously, the continuous change in the reluctance of the ferromagnetic circuit of the coil 12 generates an electromagnetic force that accelerates the projectile. The induction-type loading device requires the interaction of a primary and secondary coil to generate an electromagnetic force. A rapidly changing pulsed current is generated in the primary coil, establishing a strong magnetic field around it. Due to the magnetic field, a current is also generated in the secondary coil, thus creating a Lorentz force between the primary and secondary coils. The reluctance-type loading device does not require a large change in current, nor does it require an excessively large current. In contrast, the induction-type loading device relies on a large change in current, and the decreasing current has a reverse effect on the working process. Therefore, the reluctance-type loading device has higher energy conversion efficiency and can generate a higher force at the same voltage.

[0034] Specifically, the magnetic loading component includes a support rail assembly disposed within the housing 3. A cylindrical projectile rail 14 is disposed on the support rail assembly. A coil 12 is mounted on the projectile rail 14. The coil 12 is wrapped with insulating glue to prevent arcing and breakdown during discharge. The coil 12 is used to generate a driving force that causes the projectile 8 to move away from the top cover 2.

[0035] The housing 3 also contains a spindle assembly located on one side of the projectile guide rail 14. The spindle assembly includes a boss spindle 22 and a bossless spindle 19, which are detachably connected by threads. The end of the boss spindle 22 is used to connect with the mandrel 1.

[0036] The guide buffer assembly includes a first mass block 6, which is disposed inside the housing 3 and located between the projectile guide rail 14 and the top cover 2. One end of the first mass block 6 is connected to the projectile 8, and the other end of the first mass block 6 is connected to the end of the non-protruding spindle 19. At least one buffer block 18 is provided on the first mass block 6, and the buffer block 18 is located on the side close to the projectile 8.

[0037] The limiting ring 9 is set on the projectile guide rail 14 and is used to match the buffer block 18 to limit the travel distance of the projectile 8, thereby achieving the limiting.

[0038] Specifically, the structure of the first mass block 6 includes a cylinder. One side of the cylinder is coaxially provided with a mounting hole 1, which is threadedly connected to the bossless spindle 19. The other side of the cylinder is coaxially provided with a threaded shaft. One end of the threaded shaft is fixedly connected to the cylinder, and the other end of the threaded shaft is threadedly connected to the projectile 8, which facilitates its installation and assembly.

[0039] Specifically, multiple buffer blocks 18 for buffering force are located on the side of the cylinder of the first mass block 6 away from the second mass block 5. There can be 3-6 buffer blocks 18, which are evenly distributed on the second mass block 5. In the working state, the buffer blocks 18 on the first mass block 6 collide with the limiting ring 9, which can realize the buffering and stopping function.

[0040] Specifically, the material of buffer block 18 is ACF Artificial Cartilage Foam, which can absorb more than 90% of the impact force and instantly convert the impact energy into insignificant heat energy.

[0041] Specifically, the projectile guide rail 14 includes a cylindrical body, in which the projectile 8 is fitted. A flange is coaxially fixed at one end of the cylindrical body, and a ballistic stop block 7 is fitted and fixed inside the other end of the cylindrical body. The ballistic stop block 7 is located near the first mass block 6 to prevent the projectile 8 from slipping out of the cylindrical body. A threaded section is provided on the outer wall of the cylindrical body. An elastic baffle 11 and a washer 13 are fitted and fixed on the cylindrical body. The elastic baffle 11 is located near the limiting ring 9. Figure 2 As shown, the elastic baffle 11 is on the left side of the coil 12, and the washer 13 is on the right side of the coil 12. Together, they protect the coil.

[0042] Specifically, washer 13 is made of rubber material, and elastic baffle 11 is made of fiberglass material with internal threads to prevent damage to the coil.

[0043] To buffer the force, such as Figure 3 As shown, multiple grooves are provided on the side of the flange away from the coil 12. One end of the damper 15, the first buffer spring 23, and the second buffer spring 24 are respectively fixed in the multiple grooves, and the other ends of the damper 15, the first buffer spring 23, and the second buffer spring 24 are respectively fixed to the housing 3. The damper 15 is located in the middle position. The damper 15, the first buffer spring 23, and the second buffer spring 24 constitute the first safety component, which buffers the high speed during loading. In use, the damper 15, the first buffer spring 23, and the second buffer spring 24 buffer the high speed during loading, preventing damage to the gun body and making the operator more comfortable.

[0044] Furthermore, a second mass block 5 and a third mass block 4 are provided between the top cover 2 and the first mass block 6. A working channel is opened in the middle of the second mass block 5 and the third mass block 4. The mandrel 1 passes through the working channel. The second mass block 5 and the third mass block 4 are fitted and fixed in the housing 3. The third mass block 4 and the second mass block 5 are arranged adjacent to each other and can be fixed together with pins. The second mass block 5 is located on the side closer to the first mass block 6. The boss mandrel 22 and the bossless mandrel 19 are inserted in the second mass block 5 and the third mass block 4. The second mass block 5 and the third mass block 4 increase the mass of the loading device gun head and prevent the device from displacing significantly backward during loading.

[0045] To act as a buffer, such as Figure 4 As shown, a buffer structure 1 is provided between the first mass block 6 and the second mass block 5. The buffer structure 1 includes a plurality of buffer blocks 2 symmetrically arranged on the second mass block 5. The plurality of buffer blocks 2 are located on the side close to the first mass block 6. A plurality of buffer elastic members are also provided on the second mass block 5. The two ends of the elastic members are respectively connected to the first mass block 6 and the second mass block 5.

[0046] Specifically, such as Figure 4 As shown, the elastic element includes a third buffer spring 25, a fourth buffer spring 26, and a fifth buffer spring 27. Grooves are provided on the left side of the first mass block 6 and the right side of the second mass block 5. One end of each of the third buffer spring 25, fourth buffer spring 26, and fifth buffer spring 27 is fixed in the groove on the right side of the second mass block 5, and the groove on the left side of the first mass block 6 is close to the other end of each of the third buffer spring 25, fourth buffer spring 26, and fifth buffer spring 27. The third buffer spring 25, fourth buffer spring 26, and fifth buffer spring 27 constitute a second safety component, which is used to absorb redundant energy generated during rebound.

[0047] After the mandrel assembly moves to the right at high speed, the magnetic loading assembly will rebound to a certain extent due to the stopping effect of the buffer block 18 and the limiting ring 9. At this time, the third buffer spring 25, the fourth buffer spring 26, the fifth buffer spring 27 and multiple buffer blocks 2 on the second mass block 5 can absorb the redundant energy during the rebound.

[0048] Specifically, the material of buffer block two is preferably ACF artificial cartilage foam, which can absorb more than 90% of the impact force and convert the impact energy into insignificant heat energy in an instant.

[0049] Specifically, the limiting ring 9 includes a ring body with an internal thread on the inner wall of the ring body. The ring body is fixed to the target position on the cylinder body by adhesive bonding, so that the positions of the two are relatively fixed.

[0050] Among them, such as Figure 2 As shown, in order to adjust the stroke of the projectile 8, the position of the limiting ring 9 on the projectile guide rail 14 can also be set to adjustable.

[0051] Specifically, the limiting ring 9 includes a ring body with an internal thread on its inner wall, which is threaded to a threaded section on the cylinder. Multiple limiting holes are formed on the outer wall of the ring body, with the center line of each hole perpendicular to the center line of the ring body. These holes are used to insert connecting parts that fix the position of the ring body. The limiting ring 9 is connected to a target position on the cylinder via the connecting parts, achieving both stopping and stroke control functions. In use, the connecting parts can be loosened first, and then the ring body can be screwed down to change its position relative to the cylinder, thus adjusting the target position of the ring body and changing the required stroke.

[0052] Specifically, the connector can be a set screw 10 or a set bolt.

[0053] Specifically, such as Figure 5 As shown, a threaded through hole can be opened at 120° intervals on the limiting ring 9. The limiting ring 9 can be fixed to the cylinder by the set screw 10. When the projectile 8 moves to the right to reach the specified stroke, the limiting ring 9 will not move when the buffer block 18 on the first mass block 6 hits the limiting ring 9, which is safer.

[0054] For easy adjustment, an adjustment window structure can be provided on the housing 3 above the corresponding position of the limiting ring 9, allowing a hand to easily reach in and adjust the position of the limiting ring 9. To improve adjustment efficiency, the outer wall of the ring can be knurled to increase surface roughness, improve the reliability of force application, and prevent slippage. The adjustment window structure can also be equipped with a cover structure, which can be opened for operation when in use and closed when not in use.

[0055] To enhance energy dissipation, provide a stopping and buffering effect, and improve safety, a safety stop 21 is installed on the side of the third mass block 4 away from the second mass block 5. The safety stop 21 is bolted to the third mass block 4. A boss spindle 22 passes through the safety stop 21, with a stop channel in the middle of the safety stop 21 through which the spindle 1 can pass. The safety stop 21 is bolted to the end of the second mass block 5 near the top cover 2. The end of the boss spindle 22 that connects to the core rod 1 has an annular boss. The safety stop 21 and the boss work together to stop and buffer. When the projectile 8 travels too far, the right end of the boss spindle 22 collides with the safety stop 21, thus stopping and buffering the boss spindle 22.

[0056] The boss mandrel 22 is provided with an annular boss end with a threaded hole, which can be used to connect mandrels 1 of different diameters. The other end of the boss mandrel 22 is also provided with an internal thread to connect to the end of the bossless mandrel 19. The threaded connection makes disassembly and assembly more convenient.

[0057] Specifically, the structure of the supporting guide rail assembly includes guide rail 16 and guide rail 17, which are sequentially fixed to the housing 3. Guide rail 16 and guide rail 17 are arranged at intervals, with guide rail 17 located on the side closer to the first mass block 6. Guide rail 17 contacts the outer wall of the ring body, while guide rail 16 contacts the elastic baffle 11 and the washer 13. Guide rail 16 and guide rail 17 provide indirect support for the projectile guide rail 14, resulting in higher guiding accuracy of the projectile 8 and reducing the likelihood of radial errors.

[0058] In use, a pulsed magnetic field is generated by controlling coil 12, which causes a magnetizing current to be generated on projectile 8. The interaction between the magnetizing current and the pulsed magnetic field generates a driving force that causes projectile 8 to move to the right. Projectile 8 moves inside the cylinder of projectile guide rail 14. During this process, projectile 8 drives the first mass block 6 and the mandrel assembly to move to the right synchronously, which gives the mandrel 1 an axial tensile force, thereby pulling the mandrel 1 through the hole on the perforated specimen 28 and completing a cold extrusion strengthening process.

[0059] Furthermore, a linear bearing 20 is installed between the third mass block 4 and the boss spindle 22, or between the third mass block 4 and the bossless spindle 19. The linear bearing 20 can support and guide the linear movement of the spindle assembly, making its movement smoother.

[0060] To facilitate handheld operation, a grip is also provided on the housing 3. The grip is located in the middle of the loading device, making the operator's hand position more comfortable.

[0061] To improve the safety of the device, a heat dissipation hole is opened at the right end of the housing 3 to prevent the coil from overheating, making the loading device safer.

[0062] like Figure 2 and Figure 6 As shown, before use, the mandrel can be passed through the hole in the perforated specimen, and one end is connected to the boss mandrel 22. A pulsed magnetic field is generated by the control coil 12, causing a magnetizing current to be generated on the projectile 8. The interaction between the magnetizing current and the pulsed magnetic field generates a driving force that propels the projectile 8 to the right. The projectile 8 moves within the cylinder of the projectile guide rail 14. During this process, the projectile 8 drives the first mass block 6 and the mandrel assembly to move synchronously to the right, thus providing an axial tension to the mandrel 1, pulling it through the hole in the perforated specimen 28, completing one cold extrusion strengthening process. After the mandrel assembly moves to the right at high speed, the buffer block 18 and the limiting ring 9 stop it, achieving the functions of stopping and controlling the stroke, making the stroke of the mandrel 1 controllable.

[0063] This invention provides a magnetoresistive dynamic hole cold extrusion device that achieves dynamic cold extrusion of holes by implementing a mandrel pulling method with controllable stroke. This solves the problems of existing devices impacting the specimen surface, inability to control stroke, and difficulty in disassembling the mandrel. When using this invention, the mandrel passes through the hole in the specimen before extrusion, thus ensuring high positioning accuracy and avoiding radial deviation. A limiting ring can be selected for the required stroke and fixed at a designated position. During operation, the limiting ring and guide buffer assembly restrict the projectile's travel distance, achieving limiting. The rubber pad on the third mass block, along with the first and second buffer springs and damper, are connected to the housing, which can withstand and mitigate the high-speed impact during the high-speed cold extrusion process. Multiple buffer springs and buffer blocks on the second mass block absorb redundant energy during rebound. Furthermore, after extrusion, the mandrel is completely separated from the specimen, preventing damage to the specimen from the mandrel or drive head. It also facilitates the disassembly of the mandrel, making operation simple and safe, achieving the beneficial effects of simultaneously improving cold extrusion strengthening quality and efficiency. Meanwhile, compared to magnetic induction loading devices, magnetoresistive loading devices can generate higher electromagnetic forces under the same voltage, thus achieving the high-speed loading required for dynamic cold extrusion of holes, with high energy conversion efficiency. Using this invention, the mandrel is easy to disassemble, the surface quality of the perforated specimen is high, and the working efficiency is high, making it highly practical and worthy of promotion.

[0064] The above-disclosed embodiments are merely preferred embodiments of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. A magnetic reluctance type dynamic hole cold extrusion device, comprising a housing (3), one end of which is fitted with a conical top cover (2), the top cover (2) having a through hole forming a channel for the drawing motion of a mandrel (1), characterized in that, The housing (3) is provided with a magnetoresistive magnetic loading assembly, which includes a support rail assembly on the housing (3). The support rail assembly is provided with a cylindrical projectile rail (14). A coil (12) is fitted on the projectile rail (14). A projectile (8) is fitted inside the projectile rail (14). The coil (12) is used to generate a driving force to move the projectile (8) away from the top cover (2). The housing (3) is also provided with a mandrel assembly located on one side of the projectile rail (14). The mandrel assembly includes a detachably connected boss mandrel (22) and a bossless mandrel (19). The end of the boss mandrel (22) is used to connect with the mandrel (1). The assembly also includes: The guide buffer assembly includes a first mass block (6), which is disposed inside the housing (3) and located between the projectile guide rail (14) and the top cover (2). One end of the first mass block (6) is connected to the projectile (8), and the other end of the first mass block (6) is connected to the end of the bossless spindle (19). At least one buffer block (18) is disposed on the first mass block (6), and the buffer block (18) is located on the side close to the projectile (8). The limiting ring (9) is fitted on the projectile guide rail (14) and is used to match the buffer block (18) to achieve limiting.

2. The magnetic reluctance type dynamic hole cold extrusion device according to claim 1, characterized in that, The first mass block (6) includes a cylinder. A mounting hole is coaxially provided on one side of the cylinder. The mounting hole is threadedly connected to the bossless mandrel (19). A threaded shaft is coaxially provided on the other side of the cylinder. One end of the threaded shaft is fixedly connected to the cylinder, and the other end of the threaded shaft is threadedly connected to the projectile (8).

3. The magnetic reluctance type dynamic hole cold extrusion device according to claim 2, characterized in that, The projectile guide rail (14) includes a cylindrical body, the projectile (8) is fitted inside the cylindrical body, one end of the cylindrical body is coaxially fixed with a flange, and the other end of the cylindrical body is fitted with a fixed ballistic stop block (7). The ballistic stop block (7) is located on the side close to the first mass block (6) to prevent the projectile (8) from slipping out of the cylindrical body. The outer wall of the cylindrical body is provided with a threaded section. An elastic baffle (11) and a washer (13) are fitted and fixed on the cylindrical body. The elastic baffle (11) and the washer (13) are respectively located on both sides of the coil (12). The elastic baffle (11) is located on the side close to the limiting ring (9).

4. The reluctance type dynamic hole cold extrusion device according to claim 3, characterized in that, The flange has multiple grooves on the side away from the coil (12). One end of the damper (15), the first buffer spring (23), and the second buffer spring (24) are respectively fixed in the multiple grooves. The other end of the damper (15), the first buffer spring (23), and the second buffer spring (24) are respectively fixed to the housing (3).

5. The reluctance type dynamic hole cold extrusion device according to claim 4, characterized in that, A second mass block (5) and a third mass block (4) are provided between the top cover (2) and the first mass block (6). The second mass block (5) and the third mass block (4) are fitted and fixed inside the housing (3). The second mass block (5) is located on the side close to the first mass block (6). The boss spindle (22) and the bossless spindle (19) are inserted inside the second mass block (5) and the third mass block (4).

6. The reluctance-type dynamic hole cold extrusion device according to claim 5, characterized in that, A buffer structure is provided between the first mass block (6) and the second mass block (5). The buffer structure includes a plurality of buffer blocks 2 symmetrically arranged on the second mass block (5). The plurality of buffer blocks 2 are located on one side close to the first mass block (6). A plurality of buffer elastic elements are also provided on the second mass block (5). The two ends of the elastic elements are respectively connected to the first mass block (6) and the second mass block (5).

7. A magnetic reluctance type dynamic hole cold extrusion device according to claim 6, characterized in that, The limiting ring (9) includes a ring body, the inner wall of which is provided with an internal thread, the internal thread being threadedly connected to the threaded section on the cylinder body, and a plurality of limiting holes being provided on the outer wall of the ring body, the center line of the limiting holes being perpendicular to the center line of the ring body, the limiting holes being used to insert connecting parts that fix the position of the ring body.

8. The magnetic reluctance type dynamic hole cold extrusion device according to claim 7, characterized in that, The third mass block (4) is coaxially provided with a safety stop (21) on the side away from the second mass block (5). The boss spindle (22) passes through the safety stop (21). The end of the boss spindle (22) used to connect with the mandrel (1) is provided with an annular boss. The safety stop (21) and the boss work together to stop and buffer.

9. A magnetic reluctance type dynamic hole cold extrusion device according to claim 8, characterized in that, A linear bearing (20) is provided between the third mass block (4) and the boss spindle (22), or between the third mass block (4) and the bossless spindle (19).

10. A magnetic reluctance type dynamic hole cold extrusion device according to claim 8, characterized in that, The supporting guide rail assembly includes a first guide rail (16) and a second guide rail (17) that are fixed to the housing (3) in sequence. The first guide rail (16) and the second guide rail (17) are arranged at intervals, and the second guide rail (17) is located on the side close to the first mass block (6). The second guide rail (17) is in contact with the outer wall of the ring body, and the first guide rail (16) is in contact with the elastic baffle (11) and the washer (13).

Images