Bolt hole cold extrusion device

Abstract

The present invention discloses a bolt hole cold extrusion device, which belongs to the field of cold extrusion equipment for holes; it comprises an electric cylinder, a first extrusion device, and a second extrusion device; the first extrusion device comprises a working shaft, which comprises a shaft section, a working section, and a mounting section; the working section comprises a sleeve, and an extrusion ring is provided on the outer periphery of the sleeve; the mounting section comprises a connecting shaft integrally formed and provided at the end of the shaft section; the other end of the shaft section is provided with an internal threaded hole; the output end of the electric cylinder is provided with a threaded connector, which is threadedly connected to the internal threaded hole. Beneficial effect: the second extrusion device designs an expansion structure based on the idea of ​​converting rotational motion into radial movement, designs an arc-shaped slot on the slot through the rotation of the groove wheel, and deflects the slot by an angle along the radial direction so that the rotational sliding of the slider in the arc-shaped slot can be converted into linear motion along the radial direction, thereby realizing the conversion of rotational motion into linear motion; and further provides a stable cold pressing force for the threaded hole.

Description

Technical Field

[0001] The invention relates to a bolt hole cold extrusion device, belonging to the field of hole cold extrusion equipment. Background Art

[0002] Bolt holes play many important roles in mechanical design. They secure parts, facilitate disassembly, provide support, adjust position, prevent loosening, provide overload protection, reduce weight, and facilitate installation. Bolt holes not only serve basic connection functions but also have other important auxiliary functions, including but not limited to reducing weight, simplifying installation, and monitoring the tightening force of bolts. Given the importance of bolt holes, it is particularly important to prevent them from failing and cracking. Causes of cracks in bolt holes include excessive brittleness of the material. Studies have shown that the bolt holes on air-cooled cylinder liner fins are too brittle due to the large amount of supercooled graphite and free cementite in the material used. Repeated disassembly causing the bolt holes to reach their fatigue limit and improper sealing causing corrosive wear on the bolt holes can also cause cracks in the bolt holes, leading to connection failure.

[0003] At present, domestic and foreign scholars have conducted extensive research on hole strengthening. Many scholars have adopted various methods for hole strengthening, but cold extrusion has always been the main method for hole strengthening. Among them, the hole strengthening technology using slotted bushings is relatively mature. Its principle is to generate a certain range of compressive stress areas around the hole by extrusion, thereby forming a residual stress distribution that is conducive to improving strength. Under the action of external loads, the stress amplitude and average stress can be reduced, thereby improving the stress concentration phenomenon around the hole, thereby increasing the fatigue life of the fatigue zone of the key part of the body structure.

[0004] Meanwhile, in the prior art, cold extrusion is basically achieved by inserting a cold pressing device into a threaded hole through radial force. The applicant believes that this will damage the inner wall of the threaded hole, so a new cold extrusion structure is provided. Summary of the Invention

[0005] The object of the present invention is to provide a bolt hole cold extrusion device that can effectively solve the above-mentioned problems.

[0006] In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

[0007] It includes an electric cylinder and a first extrusion device connected to the electric cylinder, wherein a second extrusion device is provided at one end of the first extrusion device; the first extrusion device includes a working shaft, and the working shaft includes a shaft section and a working section and a mounting section provided at one end of the shaft section;

[0008] The working section includes a sleeve arranged at the end of the shaft section, and an extrusion ring is arranged on the outer periphery of the sleeve;

[0009] The mounting section includes a connecting shaft integrally formed and arranged at the end of the shaft section;

[0010] The other end of the shaft segment is provided with an internal threaded hole;

[0011] The output end of the electric cylinder is provided with a threaded connector, and the threaded connector is threadedly connected to the internal threaded hole.

[0012] Further: the second extrusion device includes an electric motor and a groove wheel arranged at the output end of the electric motor, the end face of the groove wheel is evenly distributed with arc-shaped slots, a slider is provided in the arc-shaped slot, and an expansion blade is provided on the slider, and the overall shape of the expansion blade is arc-shaped.

[0013] Further: a connecting structure is provided between the second extrusion device and the first extrusion device, the connecting structure includes an external thread provided at the end of the connecting shaft and a flange connecting piece provided in the second extrusion device, the flange connecting piece is formed by a combination of a front flange and a rear flange, one end of the front flange is provided with an internal thread matching the external thread, and the front flange and the rear flange form an installation space, the motor is fixed in the installation space, the output end of the motor is provided with a reducer, the reducer is also provided in the installation space, the output end of the reducer is connected to a coupling, the coupling is connected to a sheave shaft, and the sheave shaft cooperates with the sheave through a spline.

[0014] Furthermore: a sheave cover is also provided on the sheave, and limiting grooves are evenly distributed on the circumference of the end surface of the sheave cover, and the sliding block is slidably provided in the limiting grooves.

[0015] Furthermore: a sliding rod is provided between the arc-shaped slot and the slider, the sliding rod is inserted into the arc-shaped slot, and the slider is fixedly connected to the upper half of the sliding rod.

[0016] Furthermore: the second extrusion device also includes a protective shell, and a limiting ring is provided at one end of the protective shell.

[0017] Furthermore: a cross reinforcement rib is provided on the inner side of the expansion blade, and a mounting block with a cross groove is provided between the slider and the cross reinforcement rib for fixed connection.

[0018] The beneficial effects are:

[0019] The first extrusion device and the second extrusion device of the device can work independently, and can work in coordination by connecting the first extrusion device and the second extrusion device together through a connecting structure;

[0020] The first extrusion device, with its unique working section design, can not only be smoothly inserted into the threaded hole to be completed, but also provide stable punching force to the threaded hole;

[0021] This second extrusion device designs the expansion structure based on the idea of ​​converting rotational motion into radial movement. By rotating the groove wheel, the arc-shaped groove hole on the groove wheel is designed, and the groove is deflected at an angle along the radial direction so that the rotational sliding of the slider in the arc-shaped groove hole can be converted into linear motion along the radial direction, thereby realizing the conversion of rotational motion into linear motion; further stabilizing the cold pressing force on the threaded hole to be completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For ease of explanation, the present invention is described in detail with reference to the following specific implementations and accompanying drawings.

[0023] Figure 1 It is a structural schematic diagram of the present invention;

[0024] Figure 2 is a cross-sectional view of the present invention;

[0025] Figure 3 is a cross-sectional view of the first extrusion device of the present invention;

[0026] Figure 4 is a cross-sectional view of a second extrusion device of the present invention;

[0027] Figure 5 The motor and reducer parts diagram of the present invention;

[0028] Figure 6 It is the parts diagram of the coupling and the sheave shaft of the present invention;

[0029] Figure 7 It is a parts diagram of the sheave cover of the present invention;

[0030] Figure 8 It is the parts diagram of the sheave and expansion blade of the present invention;

[0031] Figure 9 This is a working state diagram of the first extrusion device of the present invention;

[0032] Figure 10 This is a working state diagram of the second extrusion device of the present invention;

[0033] Figure 11 This is a working state diagram of the first extrusion device combined with the second extrusion device of the present invention.

[0034] Description of reference numerals:

[0035] 1. First extrusion device; 2. Second extrusion device; 21. Motor; 22. Grooved wheel; 23. Arc-shaped slotted hole; 24. Slider; 25. Expansion blade; 26. Reducer; 27. Coupling; 28. Grooved wheel shaft; 29. ​​Sliding rod; 3. Working shaft; 31. Shaft section; 32. Working section; 321. Sleeve; 322. Extrusion ring; 323. Inclined surface; 33. Mounting section; 34. Internal threaded hole; 4. Connecting structure; 41. External thread; 42. Flange connector; 421. Front flange; 422. Rear flange; 5. Protective shell; 6. Limiting ring; 7. Cross reinforcement rib; 8. Mounting block; 10. Grooved wheel cover; 11. Limiting groove. DETAILED DESCRIPTION

[0036] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0037] It should be noted that, in the description of the present invention, unless otherwise specified, “multiple” means two or more; the terms “upper”, “lower”, “left”, “right”, “inside”, “outside”, “front end”, “rear end”, “head”, “tail”, etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] Furthermore, the terms "first," "second," "third," etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0039] Furthermore, in the description of the present invention, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; and direct connections or indirect connections through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0040] See Figure 1-11 This is an embodiment of a bolt hole cold extrusion device of the present invention.

[0041] like Figure 1 、 Figure 2The first extrusion device 1 includes an electric cylinder and a first extrusion device connected to the electric cylinder. The first extrusion device 1 includes a working shaft 3, which includes a shaft section 31, a working section 32 provided at one end of the shaft section 31, and a mounting section 33. The other end of the shaft section 31 is provided with an internal threaded hole 34. The mounting section 33 includes an integrally formed connecting shaft provided at the end of the shaft section 31.

[0042] During assembly, the electric cylinder needs to be used as a reference to start installation, and the working shaft 3 is connected to the push rod of the electric cylinder through threads; the output end of the electric cylinder is provided with a threaded connector, which is threadedly connected to the internal threaded hole 34 provided on the shaft section 31;

[0043] When the first extrusion device 1 is used, the electric cylinder is driven to push the first extrusion device 1, and the working shaft 3 is pushed toward the threaded hole to be processed; when the working section 32 is in contact, it works;

[0044] See Figure 3 The working section 32 includes a sleeve 321 arranged at the end of the shaft section 31, an extrusion ring 322 is arranged on the outer circumference of the sleeve 321, and an inclined surface 323 is arranged on the end face of the extrusion ring 322. The inclined surface 323 is pressed on the inner wall of the threaded hole at this time. Since the outer diameter of the entire extrusion ring 322 is slightly larger than the inner diameter of the threaded hole, the electric cylinder needs to exert a very strong thrust to push the extrusion ring 322 into the threaded hole. At this time, due to the setting of the sleeve 321, the entire sleeve 321 will be slightly deformed; the internal stress of the sleeve 321 provides a force for the threaded hole, thereby completing the cold extrusion of the threaded hole.

[0045] like Figure 4 , for the second extrusion device 2:

[0046] Then, the front and rear flanges are connected to the working shaft 3 through threads, and the internal motor and reducer are connected to the sheave shaft 28 through a coupling. The sheave 22 and the sheave shaft 28 are connected by interference fit. The sheave 22 is then fixed by a ring groove nut. Then, the sheave 22 is connected to the slider 24 in the sheave cover 10 with a connecting shaft, and then the expansion blades are installed. Finally, the protective shell 5 is fixed to the front and rear flanges and the sheave cover 10.

[0047] A second extrusion device 2 is provided at one end of the first extrusion device 1; the second extrusion device 2 is also a structure for cold pressing the threaded hole to be processed;

[0048] The second extrusion device 2 includes a motor 21 and a groove wheel 22 arranged at the output end of the motor 21. The end surface of the groove wheel 22 is uniformly distributed with arc-shaped slots 23. A slider 24 is provided in the arc-shaped slots 23. The slider 24 is provided with an expansion blade 25. The overall shape of the expansion blade 25 is arc-shaped.

[0049] See Figure 4-8 , Figure 10When the second extrusion device 2 is in use, the motor 21 drives the groove wheel 22 to rotate. At this time, the position of the arc slot 23 on the groove wheel 22 changes, so that the slider 24 slides under the influence of the arc slot 23. Then the slider 24 drives the expansion blade 25 to move, and the expansion blade 25 presses on the inner wall of the threaded hole to complete the cold extrusion work of the threaded hole.

[0050] The second extrusion device 2 is designed with the idea of ​​converting rotational motion into radial movement to design the expansion structure. Through the rotation of the groove wheel 22, the arc-shaped slot hole 23 on the groove wheel 22 is designed, and the slot is deflected at an angle along the radial direction so that the rotational sliding of the slider 24 in the arc-shaped slot hole 23 can be converted into a linear motion along the radial direction, thereby realizing the conversion of rotational motion into linear motion.

[0051] This device is used to strengthen bolt holes with diameters of 80mm-100mm, limiting the maximum expansion diameter based on this size. Therefore, two extreme positions were determined, with a minimum of 80mm and a maximum of 100mm. After modifying some data during modeling, the maximum diameter of the expansion device was ultimately determined to be 98mm. Based on the working shaft's small outer diameter of 86mm, the minimum diameter of the expansion device was designed to be 86mm, meeting the design requirements of the mechanism.

[0052] See Figure 8 A cross reinforcement rib 7 is provided on the inner side of the expansion blade 25, and a mounting block 8 with a cross groove is provided between the slider 24 and the cross reinforcement rib 7 for fixed connection.

[0053] According to the working shaft's minimum outer diameter of 86mm, the expansion blade's outer diameter is determined to be 86mm and its inner diameter is 80mm.

[0054] The blade thickness is 3 mm. Since the blade is designed to be relatively thin, in order to effectively improve the overall strength and rigidity of the blade, a cross reinforcement rib 7 is added inside the expansion blade 25. This can effectively improve the seismic resistance of the structure, increase the ductility and energy absorption capacity of the structure, thereby reducing the deformation and damage of the structure. The cross reinforcement rib 7 can effectively control the expansion of cracks in the structure.

[0055] When subjected to external loads or stress concentration caused by structural deformation, the cross reinforcement ribs 7 can limit the expansion of cracks and maintain the integrity and stability of the structure; the cross reinforcement ribs 7 can improve the durability of the structure and extend the service life of the structure.

[0056] The cross-grooved mounting block 8 reduces stress concentration and fatigue damage, lowers maintenance costs, and improves long-term stability. The cross-reinforcement ribs 7 improve the structure's deformation performance, reducing its deformation under load. A bevel is designed on one side of the expansion blade 25 for transition purposes. To allow for expansion, the blade is 1 / 6 of a circular ring, with a 60° angle between the bevels on both sides. The ribs on the blade are 4.35 mm high.

[0057] Since the expansion blade 25 plays the role of squeezing the hole wall, the material of the bolt hole is aluminum alloy, and the stress on the bolt hole wall is greater than its yield strength, it is necessary to select a metal with a yield strength greater than that of aluminum alloy. Selecting 45 steel and performing a modulation process can meet the requirements.

[0058] In this device, a sliding rod 29 is provided between the arc-shaped slot 23 and the slider 24 . The sliding rod 29 is inserted into the arc-shaped slot 23 , and the slider 24 is fixedly connected to the upper half of the sliding rod 29 .

[0059] See Figure 8 , the sheave 22 in this application document needs to have six arc-shaped slots 23 for mounting the sliding rod 29, so that the axial rotational motion is converted into radial linear motion through the rotation of the sheave 22. Therefore, in order to make the radial displacement of the sliding rod 29 in the slot reach 6 mm, so that the minimum and maximum diameters of the expansion device are 86 mm and 98 mm respectively, the shape and position distribution of the slots on the sheave 22 are designed according to this size, and the six arc-shaped slots 23 are evenly distributed with the center of the sheave 22 as the axis;

[0060] Since the sheave 22 needs to rotate, in order to minimize its mass and thus reduce its moment of inertia, a smaller diameter is selected as much as possible, and the outer diameter of the sheave 22 is finally designed to be 50 mm; for the inner diameter of the sheave 22, a larger size should be selected as much as possible, and the inner diameter of the sheave 22 is finally designed to be 15 mm.

[0061] Since the groove wheel 22 needs to rotate, torque needs to be transmitted. First, the design is to mill a keyway on the inner diameter of the groove wheel 22 and connect it with an ordinary flat key. However, the contact area between the flat key and the hole slot is limited. When subjected to external loads, stress concentration may occur on the surface of the flat key and the hole slot, increasing the stress and possible fatigue damage of the material. In addition, the locking of the flat key connection depends on the tight fit between the key and the hole slot. If the fit is poor or loose, it will lead to unreliability and failure risk of the connection. High-precision processing and installation processes are required in the manufacture and installation of flat key connections, especially for large or complex-shaped flat keys, the processing and installation process may be more difficult and time-consuming. Ordinary flat key connections require a certain amount of space to accommodate the flat key itself and the hole slot, which may cause an increase in the gap between the connecting parts, thereby affecting the compactness and performance of the overall structure. Ordinary flat key connections may cause vibration and noise problems due to poor locking or loosening, especially when running at high speeds or subjected to impact loads.

[0062] To avoid this, the fixed connection portion of the sheave 22 has been appropriately improved. The keyway required for the flat key has been removed, and three protrusions have been directly fixed to the sheave 22. The keyway on the sheave 22 shaft that cooperates with it achieves an interference fit with these three protrusions. The interference fit prevents circumferential movement during transmission and also allows torque to be transmitted. In addition, considering that the interference fit connection requires a wrench for installation and removal, the connection space between the sheave 22 and the sheave 22 shaft is large, so there is no need to reserve a hole for the wrench. The groove depth of the sheave 22 is designed to be 5mm. Since the bottom of the sheave 22 is not subjected to much force, the size of the bottom does not need to be designed too large. Therefore, the overall thickness of the sheave 22 is 7.5mm.

[0063] The device requires the sliding rod 29 to slide in the arc-shaped slot hole 23 of the sheave 22. Therefore, the sheave 22 alone cannot fix it in the sliding plane, and a sheave cover 10 needs to be designed to limit the movement of the slider 24. When designing the sheave cover 10, its outer diameter is determined according to the inner diameter of the expansion blade 25 minus the height of the cross reinforcement rib 7. The radius of the inner diameter of the expansion blade 25 has been designed to be 40 mm, and the height of the cross reinforcement rib 7 of the expansion blade 25 is 4.35 mm. Therefore, the diameter of the sheave cover 10 is designed to be 70 mm, and no interference will occur when the expansion blade 25 is closed. In order to realize the movement of the expansion device, 6 limiting grooves 11 need to be designed on the sheave cover 10, and the sheave cover 10 needs to be fixed, so that the movement in the limiting grooves 11 on the sheave cover 10 transmitted through the rotational movement of the sheave 22 becomes a linear motion. Therefore, evenly distributed threaded holes are provided between the limiting grooves 11 of the sheave cover 10 for fixed connection of the sheave cover 10. The sheave cover 10 is made of 45# steel.

[0064] The thickness of the sliding rod 29 in this application is determined by the depth of the arcuate slot 23 of the sheave 22. The arcuate slot 23 is designed to be 5mm deep, so the thickness of the sliding rod 29 is also 5mm. The thickness of the slider 24 is 10mm, and its material is 45# steel and is modulated. The difference between the sliding rod 29 in the sheave 22 and the sliding rod 29 is that the sliding rod 29 in the sheave 22 is designed to be arc-shaped on both sides because it performs circular motion, while the slider 24 in the sheave cover 10 performs linear motion within the fixed sheave cover 10, so its two sides are flat. Its length is designed so that the bottom of the expansion blade 25 does not interfere with each other when it is closed, and sufficient distance is left between the head and the cross reinforcement rib 7 of the expansion blade 25 to design the mounting block 8 with a cross groove.

[0065] A connecting structure 4 is provided between the second extrusion device 2 and the first extrusion device 1. The connecting structure 4 includes an external thread 41 provided at the end of the connecting shaft and a flange connection 42 provided in the second extrusion device 2. The flange connection 42 is formed by a front flange 421 and a rear flange 422. An internal thread matching the external thread 41 is provided at one end of the front flange 421, and the front flange 421 and the rear flange 422 form an installation space. The motor 21 is fixed in the installation space. A reducer 26 is provided at the output end of the motor 21, and the reducer 26 is also provided in the installation space.

[0066] Since the device is used to achieve cold extrusion strengthening of bolt holes with thicker and thinner walls, it is not enough to design only a drawing working shaft 3. Considering that the electric cylinder cannot achieve both drawing and expansion movements, it is necessary to connect an electric motor 21 and a reducer 26 to provide a larger torque, and convert the torque into radial pressure through a specific device. Therefore, it is necessary to design a space at the other end of the working shaft 3 connected to the electric cylinder to install the motor 21. After selecting the motor 21 and the reducer 26, a front flange 421 of a section of the working shaft 3 is designed. The installation space between the front flange 421 and the rear flange 422 is used to fix the motor 21 and the reducer 26.

[0067] The size of the spaces inside the front flange 421 and the rear flange 422 is determined according to the size of the fixing flange of the motor 21 , so that the space inside the front flange 421 allows for an interference fit after the motor 21 is installed.

[0068] After designing the front flange 421, the motor 21 and the reducer 26 need to be fixed in the hollow part in the middle of the front flange. Therefore, a rear flange 422 needs to be designed to match the front flange 421, and the flange on the reducer 26 needs to be fixed on the rear flange 422 to prevent the vibration generated by the motor 21 and the reducer 26 during operation from loosening the fixed parts. Therefore, after measuring the length of the motor 21 and the reducer 26 after matching, the size of the rear flange 422 is determined, and the threaded holes on the rear flange 422 are designed according to the threaded holes on the fixed flange on the reducer 26; the length of the motor 21 and the reducer 26 after matching is 45.07mm, and the length of the hollow part inside the front flange 421 for installing the motor 21 is 12mm, so the length of the rear flange 422 is 33.07mm.

[0069] The output end of the reducer 26 is connected to a coupling 27 , and the coupling 27 is connected to a sheave shaft 28 . The sheave shaft 28 is engaged with the sheave 22 via a flat key.

[0070] The coupling 27 in this device is selected according to the diameter of the output shaft of the reducer 26. Since the diameter of the output shaft of the selected reducer 26 is 6.25 mm, the inner diameter of the coupling 27 is also selected to be 6.25 mm, and the ML2 coupling is finally selected.

[0071] The sheave shaft 28 is interference-fitted with the protrusion of the sheave 22 to prevent vibration of the sheave 22 on the sheave shaft 28. The interference fit also allows for torque transmission. Therefore, the diameter of the shaft section that mates with the sheave 22 is 15 mm, and the diameter of the shoulder that axially secures the sheave 22 is 20 mm to limit axial displacement of the sheave 22. The other side of the sheave 22 is externally threaded and axially secured with a ring nut. The ring nut is made of 45 steel and has been quenched and tempered.

[0072] The second extrusion device 2 further includes a protective shell 5 , and a limiting ring 6 is provided at one end of the protective shell 5 .

[0073] The design of the protective shell 5 in this device is that the bolt hole cold extrusion strengthening device needs to fix the sheave cover 10 to realize the expansion and extrusion function. Therefore, it is necessary to design a connecting device to connect the assembly of the stationary front flange 421 and the rear flange 422 to the sheave cover 10, and at the same time, the motor 21, the reducer 26, the coupling 27, the sheave shaft 28, the sheave 22 and other parts can be sealed; the protective shell 5 can effectively protect the internal components or elements of the system from the influence of the external environment, such as dust, moisture, corrosive substances, etc., which helps to extend the service life and reliability of the mechanical equipment; sealing the internal parts can improve the safety of the system; it can improve the adaptability of the mechanical equipment in harsh environments. For example, in high temperature, low temperature, high humidity or corrosive environment, the sealing mechanism can effectively protect the internal components and ensure the normal operation of the equipment.

[0074] Therefore, after assembling the internal parts, the size of the protective shell 5 was determined. Through measurement, the size of the protective shell 5 was found to be 99.15mm, so the total length was determined when designing the protective shell 5. Then, the thickness of the flanges on both sides of the protective shell 5 connected to the rear flange and the sheave cover were determined, and the threaded holes that matched them were determined. The flange thicknesses were determined to be 3mm and 6.51mm respectively. Finally, to prevent the protective shell 5 from interfering with the inclined portion of the expansion blade 25, the size of the protective shell 5 was finally determined after data adjustment. The material was selected as 45 steel and then modulated.

[0075] See Figure 11 When the first extrusion device and the second extrusion device are used in combination, the electric cylinder is first controlled to push the second extrusion device into the threaded hole without thread processing, and then the second extrusion device is started to press the expansion blade 25 into the threaded hole to perform the first stage of cold extrusion;

[0076] After the first stage of cold extrusion is completed, the expansion blade 25 is retracted and the electric cylinder is continued to be controlled to push. At this time, the sleeve 321 of the first extrusion device will be pressed into the threaded hole, and the extrusion ring 322 will be pressed against the inner wall of the threaded hole; then the second extrusion device is started to press the expansion blade 25 against the inner wall of the threaded hole; in this way, the entire inner wall of the threaded hole can be cold extruded.

[0077] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A bolt hole cold extrusion device, characterized in that: The invention comprises an electric cylinder and a first extrusion device (1) connected to the electric cylinder, wherein a second extrusion device (2) is provided at one end of the first extrusion device (1); the first extrusion device (1) comprises a working shaft (3), the working shaft (3) comprises a shaft section (31), a working section (32) and a mounting section (33) provided at one end of the shaft section (31); the working section (32) comprises a sleeve (321) provided at the end of the shaft section (31), and an extrusion ring (322) is provided on the outer periphery of the sleeve (321); the mounting section (33) comprises a connecting shaft integrally formed and provided at the end of the shaft section (31); the other end of the shaft section (31) is provided with an internal threaded hole (34); the output end of the electric cylinder is provided with a threaded connector, and the threaded connector is threadedly connected to the internal threaded hole (34); The second extrusion device (2) comprises a motor (21) and a groove wheel (22) arranged at the output end of the motor (21), the end surface of the groove wheel (22) is uniformly distributed with arc-shaped slots (23), a slider (24) is arranged in the arc-shaped slots (23), and an expansion blade (25) is arranged on the slider (24), and the overall shape of the expansion blade (25) is arc-shaped; A connecting structure (4) is provided between the second extrusion device (2) and the first extrusion device (1), the connecting structure (4) comprising an external thread (41) provided at the end of the connecting shaft, and a flange connection member (42) provided in the second extrusion device (2), the flange connection member (42) being formed by a combination of a front flange (421) and a rear flange (422), one end of the front flange (421) being provided with an internal thread matching the external thread (41), and the front flange (421) and the rear flange (422) forming an installation space, the motor (21) being fixed in the installation space, the output end of the motor (21) being provided with a reducer (26), the reducer (26) being also provided in the installation space, the output end of the reducer (26) being connected to a coupling (27), the coupling (27) being connected to a sheave shaft (28), the sheave shaft (28) being matched with the sheave (22) via a spline; A sheave cover (10) is further provided on the sheave (22), and limiting grooves (11) are evenly distributed on the circumference of the end surface of the sheave cover (10), and the slider (24) is slidably provided in the limiting grooves (11).

2. The bolt hole cold extrusion device according to claim 1, characterized in that: A sliding rod (29) is provided between the arc-shaped slot hole (23) and the slider (24), the sliding rod (29) is inserted into the arc-shaped slot hole (23), and the slider (24) is fixedly connected to the upper half of the sliding rod (29).

3. The bolt hole cold extrusion device according to claim 2, characterized in that: The second extrusion device (2) further comprises a protective shell (5), and a limiting ring (6) is provided at one end of the protective shell (5).

4. The bolt hole cold extrusion device according to claim 3, characterized in that: A cross reinforcement rib (7) is provided on the inner side of the expansion blade (25), and a mounting block (8) with a cross groove is provided between the slider (24) and the cross reinforcement rib (7) for fixed connection.

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