Spiral-edge crushing cutter and preparation process thereof

Abstract

The invention relates to the technical field of machining tools, and discloses a spiral blade crushing cutter which comprises a spiral blade formed by splicing at least two hollow spiral cutter sleeve modules in the axial direction, and an inner hole of each spiral cutter sleeve module is a prismatic table-shaped matching hole; the combined cutter shaft penetrates through the spiral blade and comprises a prismatic table core shaft matched with the prismatic table-shaped matching hole, and rotating shafts are arranged at the two ends of the prismatic table core shaft; wherein a shaft shoulder used for axial positioning is arranged at one end of the prismatic table core shaft, and a locking mechanism used for applying axial pre-tightening force is arranged at the other end of the prismatic table core shaft. The whole long spiral cutter shaft is divided into a plurality of standard spiral cutter sleeve modules, the size of a single module is small, high-precision machining and heat treatment are easy to carry out, the rate of finished products is high, when a local cutting edge is damaged, only the damaged module needs to be replaced, overall scrapping is avoided, low-cost and rapid field maintenance is achieved, and the service life of the long spiral cutter shaft is prolonged. And the maintenance cost and time are greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of machining tool technology, specifically to a spiral-bladed crusher and its manufacturing process. Background Technology

[0002] In industrial fields such as solid waste treatment and biomass crushing, cutter shafts equipped with multiple disc-shaped blades or short blades are widely used for material crushing. Traditional crushing cutter shafts usually adopt a split structure, which consists of a separate shaft and multiple independent cutter discs assembled through connecting parts such as keyways and flanges.

[0003] This traditional split structure has several inherent drawbacks: First, the clearance between the cutter head and the shaft is prone to fretting wear and loosening under high-speed and high-load impact conditions, resulting in loss of transmission accuracy, abnormal noise, and even keyway wear or key shearing failure. Secondly, the assembly gap between adjacent cutter heads provides space for long strips of materials such as fibers and ropes to become entangled, which can easily lead to the phenomenon of "entanglement shaft", increasing the operating load, making cleaning difficult, and seriously affecting the continuous operation efficiency of the equipment. Furthermore, since it is assembled from multiple independent parts, the coaxiality and dynamic balance accuracy of the entire cutter shaft assembly are difficult to guarantee. It generates a lot of vibration and noise when running at high speed, which affects the stability and service life of the whole machine.

[0004] To address the aforementioned issues, existing technologies have developed integral spiral cutting edge cutter shafts, which involve machining continuous spiral ridges on the outer surface of a single shaft using CNC milling or other methods to create the cutting edge. However, this integral solution also has significant drawbacks: the integral milling of large, long shafts results in substantial material waste, low machining efficiency, and high tool wear. If severe chipping or wear occurs in a localized area of ​​the spiral cutting edge, the entire expensive cutter shaft will need to be replaced, leading to extremely high maintenance costs. Furthermore, when performing heat treatments such as quenching on such a large integral part to obtain a high-hardness cutting edge, bending deformation is highly likely to occur, and correction is extremely difficult.

[0005] Therefore, there is an urgent need in this field for a new type of crushing blade structure and its manufacturing method that can avoid the connection and entanglement problems of split structures and overcome the difficulties in processing, high cost and inconvenience of maintenance of integral structures. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a spiral blade crusher and its manufacturing process. The blade adopts a modular assembly and keyless connection design, which aims to achieve a continuous spiral cutting edge, high connection reliability, anti-winding and convenient maintenance. Its manufacturing process aims to solve problems such as gradient material preparation of modular cutter shaft, heat treatment deformation control and high-precision reliable assembly.

[0007] This invention proposes a spiral blade shredder, comprising: a spiral blade, formed by axially splicing at least two hollow spiral blade sleeve modules, wherein the inner hole of the spiral blade sleeve module is a frustum-shaped mating hole; a combined blade shaft, penetrating the spiral blade, comprising a frustum-shaped mandrel adapted to the frustum-shaped mating hole, wherein the frustum-shaped mandrel has rotating shafts at both ends; wherein, one end of the frustum-shaped mandrel has a shoulder for axial positioning, and the other end has a locking mechanism for applying axial preload; the spiral blade sleeve module achieves circumferential limiting through the frustum-shaped mating hole and the conical surface of the frustum-shaped mandrel, and the axial preload applied by the locking mechanism ensures that the two are tightly fitted, transmitting torque through friction; Addressing the issues of traditional pulverizer blades—such as "split-type blades prone to loosening and tangling, and integral-type blades with high maintenance costs"—this tool achieves a breakthrough through "modular splicing + keyless friction transmission." The spiral blade is composed of multiple spiral blade sleeve modules. If a single module is damaged, only replacement is required, eliminating the need for complete scrapping and significantly reducing maintenance costs. The frustum-shaped mating hole mates with the conical surface of the frustum-shaped mandrel. Combined with the axial preload applied by the locking mechanism, sufficient friction is generated at the contact surface to transmit torque, replacing the traditional key connection. This eliminates mating gaps and fretting wear, making it suitable for high-speed, heavy-duty pulverizing conditions (such as solid waste treatment and biomass pulverization). The spliced ​​spiral blade forms a continuous surface without assembly gaps, fundamentally solving the problem of long materials tangling around the shaft and ensuring continuous operation of the equipment. At the same time, the modular design reduces processing difficulty, improves yield, and balances reliability and economy.

[0008] As a further optimization of the present invention, the locking mechanism includes an end cap and a hydraulic nut sequentially fitted onto the rotating shaft. The end cap presses against the end face of the spiral cutter sleeve module, and the hydraulic nut is used to apply axial tension to the frustum mandrel. The locking mechanism works in tandem with the end cap and hydraulic nut. The end cap presses against the end face of the spiral blade sleeve module to ensure that the axial pressure is evenly transmitted to all modules, avoiding module misalignment caused by uneven local force. The hydraulic nut can precisely apply axial tension, making the frustum mandrel and the frustum-shaped mating hole fit tightly together, generating stable friction. The tension can be adjusted as needed to adapt to different torque requirements. Compared with traditional mechanical nuts, hydraulic nuts have a larger and more uniform preload, which can effectively resist the impact load during crushing and prevent loosening of the connection. At the same time, they are easy to disassemble and assemble, facilitating module replacement and maintenance.

[0009] As a further optimization of the present invention, the mating end faces of two adjacent spiral blade sleeve modules are provided with mutually meshing end face meshing teeth. After axial pre-tightening, the end face meshing teeth mesh with each other. On the one hand, they accurately position the circumferential phase of adjacent modules, ensuring that the spiral protrusions after splicing are connected end to end, forming a continuous spiral cutting edge, avoiding the cutting edge breakage caused by circumferential misalignment. On the other hand, they participate in torque transmission, assisting friction to jointly bear the working torque, further improving the connection reliability. They are especially suitable for high-impact crushing scenarios (such as hard material crushing). The meshing structure can also reduce the wear of the module docking end face, extend the module service life, and improve the coaxiality after assembly, reducing vibration and noise during high-speed operation.

[0010] As a further optimization of the present invention, the cross-section of the frustum-shaped mating hole and the frustum-shaped mandrel is a regular polygonal frustum structure. Regular polygonal frustum structures (such as regular hexagonal frustums and regular octagonal frustums) make the contact surfaces between the frustum mandrel and the mating hole multiple evenly distributed planes. Compared with circular conical surfaces, they can transmit pressure and torque more evenly, avoid local stress concentration, and the planar fit facilitates machining and precision control, ensuring the compatibility of the module and the mandrel, reducing assembly gaps. The regular polygonal structure can also restrict circumferential rotation, assisting in achieving reliable torque transmission, adapting to the design requirements of keyless connections, and taking into account both structural stability and machining feasibility.

[0011] As a further optimization of the present invention, the regular polygonal frustum structure is a regular octagonal frustum structure. Compared with other regular polygons, the regular octagonal frustum structure has more contact surfaces, which can more evenly distribute pressure and torque, reduce the load on a single contact surface, and reduce wear. At the same time, the fitting accuracy of the eight facets is easy to control. During processing, multi-face grinding can be used to ensure the facets are flat and improve the tightness of the fit. In addition, the cone angle of the regular octagonal frustum is more suitable for the friction force transmission requirements. Under the same axial preload, it can generate a larger contact normal pressure, further enhancing the torque transmission capability and adapting to medium and high torque crushing conditions.

[0012] A manufacturing process for the aforementioned spiral blade crushing tool includes a spiral blade sleeve module manufacturing step, wherein the spiral blade sleeve module manufacturing step includes: S1: using powder metallurgy technology, through gradient filling and integral sintering, to prepare a spiral blade sleeve module green blank with a composite material structure of a cutting edge region and a matrix region; S2: simultaneously quenching the sintered spiral blade sleeve module with dual media to make the cutting edge region and the matrix region obtain different hardness and toughness. The manufacturing process addresses the contradiction between "hard cutting edge and tough substrate" in cutting tools by using "powder metallurgy gradient materials + differentiated quenching". The gradient loading uses high-hardness wear-resistant materials (such as cemented carbide powder) in the cutting edge area and high-toughness alloy powder in the substrate area. Integrated sintering achieves interfacial metallurgical bonding, avoiding the problem of easy peeling of traditional weld overlay coatings. Simultaneous dual-medium quenching uses different cooling methods for different areas, enabling the cutting edge to achieve high hardness (meeting wear resistance requirements) and the substrate to maintain high toughness (resisting impact fracture). This eliminates the need for multiple subsequent heat treatments, simplifies the process, controls deformation, improves module precision, and lays the foundation for subsequent precise assembly.

[0013] As a further optimized solution of the present invention, in step S1, the gradient filling specifically involves: first filling the mold with high-hardness wear-resistant material powder to form the cutting edge area, and then filling with high-toughness alloy steel powder to form the matrix and inner hole area. Gradient filling involves dividing the powder into zones according to functional requirements. The high-hardness material in the cutting edge area ensures wear resistance during crushing and extends the cutting edge life. The high-toughness material in the matrix and inner hole areas enhances the overall impact resistance of the module and prevents the module from breaking when crushing hard materials. The use of tough material in the inner hole area can also reduce wear when mating with the truncated pyramid mandrel and ensure mating accuracy. The zoned powder filling uses a mold to precisely control the material distribution, ensuring clear boundaries and uniform transitions in each area. After integral sintering, a continuous gradient material structure is formed with no obvious interface defects, balancing functionality and structural stability.

[0014] As a further optimized solution of the present invention, in step S2, the synchronous dual-medium quenching specifically involves: gas quenching the cutting edge area of ​​the hot spiral tool sleeve module, while oil quenching the base and inner hole areas. Simultaneous dual-medium quenching selects the cooling medium according to the characteristics of different areas: gas quenching has a fast cooling rate, which allows the cutting edge area to quickly form a martensitic structure and obtain high hardness; oil quenching has a moderate cooling rate, which allows the matrix and inner hole areas to form a structure with better toughness and avoid cracking. This process can complete the heat treatment of different areas in one go, without the need for multiple treatments, reducing module deformation (such as bending and cracking), while ensuring a balance between cutting edge hardness and matrix toughness. It meets the dual requirements of "cutting edge wear resistance and matrix impact resistance" during crushing, and improves the overall performance of the tool.

[0015] As a further optimization of the present invention, after the preparation step of the spiral cutter sleeve module, an assembly step is also included. The assembly step includes: Step 1: Deep rolling and shot peening composite strengthening treatment of the frustum mandrel; Step 2: Using the temperature difference method, the spiral cutter sleeve module is fitted onto the frustum mandrel; Step 3: Using a hydraulic nut to pre-tighten the assembly with torque-displacement dual control. The assembly process ensures connection reliability through "strengthening, temperature difference assembly, and precise pre-tightening." Step one, the composite strengthening treatment, forms a residual compressive stress layer on the surface of the frustum mandrel, improving its fatigue resistance and wear resistance, and extending the mandrel's lifespan. Step two, the temperature difference method, utilizes the principle of thermal expansion and contraction to reduce assembly difficulty, ensuring a tight fit between the module and the mandrel while reducing assembly stress. Step three, the torque-displacement dual-control pre-tightening, uses the mandrel's elastic elongation as the judgment standard to precisely control the pre-tightening force, avoiding pre-tightening deviations caused by relying solely on torque or pressure. This ensures consistency among different assemblies, adapts to mass production needs, and guarantees connection rigidity to resist crushing impacts.

[0016] As a further optimization of the present invention, step three specifically includes: first, applying an initial preload through a hydraulic system, and then using the elastic elongation of the frustum mandrel reaching a predetermined value as the criterion for terminating the preload. Precise pre-tightening is achieved through "initial pre-tightening + displacement control": the initial pre-tightening force eliminates the macroscopic gap between the module and the mandrel, allowing the component to enter the elastic deformation zone. The elastic elongation of the mandrel is used as the termination standard, bypassing the indirect conversion of "pressure-friction-pre-tightening force". It directly uses the physical deformation as the basis and automatically compensates for errors caused by factors such as thread friction and hydraulic efficiency, ensuring that the pre-tightening force is precise and consistent. This method avoids the uncertainty of traditional pre-tightening methods, stabilizes the connection strength of different assemblies, reduces early failures caused by pre-tightening deviations, simplifies the operation process, improves assembly efficiency, and is suitable for industrial mass production.

[0017] The spiral blade pulverizer and its manufacturing process proposed in this invention have the following beneficial effects: (i) The entire long spiral cutter shaft is decomposed into multiple standard spiral cutter sleeve modules. Each module is small in size, easy to perform high-precision machining and heat treatment, and has a high yield. When a local cutting edge is damaged, only the damaged module needs to be replaced, avoiding the scrapping of the whole unit. This achieves low-cost and fast on-site repair, and greatly reduces maintenance costs and time. (ii) Through the huge axial preload applied by the frustum-conical surface and the hydraulic nut, the frictional force at the contact surface is generated to transmit the torque, which is far greater than the working torque. This eliminates the gap, fretting wear and stress concentration problems of traditional key connections, and significantly improves the rigidity and reliability of the connection. It is especially suitable for high-speed, heavy-load and high-impact crushing conditions. (iii) After precision assembly, the spiral protrusions on the outside of the multiple spiral blade modules are connected end to end to form a continuous and seamless spiral cutting edge on a macroscopic scale. This continuous surface effectively eliminates the gaps that can be used for fibrous materials to wrap around, fundamentally solving the problem of "winding shaft" and ensuring the continuous and stable operation of the equipment. (iv) The modular structure allows for the precision machining and screening of individual spiral cutter sleeve modules, and the precise end face meshing teeth ensure circumferential phase, so that the assembled cutter shaft has excellent coaxiality and dynamic balance performance, thereby reducing vibration and noise during high-speed operation and extending the life of bearings and equipment. (v) The supporting preparation process adopts advanced methods such as powder metallurgy gradient composite material technology, synchronous dual-medium quenching, and magnetic field-assisted precision grinding, which realizes the combination of high hardness of the cutting edge and high toughness of the matrix from the material source, and effectively controls heat treatment deformation, thereby improving the wear resistance and fatigue strength of key components.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is a schematic diagram of the overall cross-sectional structure of the present invention; Figure 3 This is a schematic cross-sectional view of the spiral blade of the present invention; Figure 4 This is a three-dimensional structural schematic diagram of the spiral blade sleeve module of the present invention; Figure 5 This is a schematic diagram of the end face structure of the spiral blade sleeve module of the present invention.

[0020] Figure descriptions: 1. Spiral cutter sleeve module; 11. Frustum-shaped mating hole; 2. Combined cutter shaft; 21. Frustum-shaped mandrel; 22. Rotating shaft; 3. Shoulder; 4. End cap; 5. Hydraulic nut; 6. End face meshing teeth. Detailed Implementation

[0021] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0022] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] Please see Figures 1-5 A spiral blade crusher includes a spiral blade and a combined blade shaft 2 that penetrates the inner hole of the spiral blade. The spiral blade has a through frustum-shaped mating hole 11 along its axial direction. The combined blade shaft 2 includes a frustum-shaped spindle 21. Both ends of the frustum-shaped spindle 21 are equipped with rotating shafts 22. The spiral blade is fitted onto the frustum-shaped spindle 21 through the frustum-shaped mating hole 11 to restrict the relative rotation between the spiral blade sleeve module 1 and the frustum-shaped spindle 21. The frustum mandrel 21 has a shoulder 3 on one end face. The diameter of the shoulder 3 is larger than the diameter of the large-diameter end of the frustum-shaped mating hole 11. It serves as a reference surface for the axial assembly of the spiral cutter sleeve module 1 and is used to abut the end of the spiral cutter sleeve module 1. On the other side of the frustum mandrel 21, there is an end cap 4 and a hydraulic nut 5 fitted onto the rotating shaft 22. The end cap 4 presses against the outer side of the small-diameter end of the spiral cutter sleeve module 1. A huge axial tensile force is applied to the mandrel through the hydraulic nut 5. This axial tensile force attempts to pull the frustum mandrel 21 into the frustum-shaped mating hole 11. According to the principles of mechanics, this axial force will decompose on the contact surface between the frustum mandrel 21 and the spiral cutter sleeve module 1, generating a huge normal pressure N, N = F. axial / (sin(a / 2)*μ), where a is the cone angle of the polygonal surface and μ is the coefficient of friction. The normal pressure N immediately generates a huge static friction force F1 on the contact surface. The sum of multiple static friction forces is much greater than the tangential force calculated from the maximum torque Tmax that the cutter shaft needs to transmit when it is working. The torque will be transmitted entirely through the friction between the contact surfaces without relying on additional components such as keys and pins.

[0024] In one embodiment, the spiral blade includes multiple hollow spiral blade sleeve modules 1 arranged along its length. Each spiral blade sleeve module 1 is shaped as a multi-headed spiral body with a frustum-shaped inner hole. Multiple spiral blade sleeve modules 1 are spliced ​​together so that multiple frustum-shaped holes are seamlessly spliced ​​to form a frustum-shaped mating hole 11. When multiple spiral blade sleeve modules 1 are sequentially fitted onto the frustum mandrel 21, they can be rotated to a specific circumferential angle to ensure that the spiral protrusions of adjacent spiral blade sleeve modules 1 can be connected end to end, thereby forming multiple continuous and uninterrupted spiral lines. A huge axial force is applied from one end of the frustum mandrel 21 by the hydraulic nut 5, pulling the frustum mandrel 21 into the helical blade. The axial force generates a huge contact pressure between the frustum mandrel 21 and the frustum-shaped mating hole 11. The resulting friction is much greater than the maximum torque during operation, realizing keyless torque transmission. At the same time, the huge axial compressive stress makes all the helical cutter sleeve modules 1 press tightly together, generating friction on the contact end face, preventing circumferential misalignment, thus forming a seamless and continuous integral helical cutter shaft on a macroscopic level.

[0025] Specifically, each frustum-shaped hole that makes up the frustum-shaped fitting hole 11 is surrounded by multiple tapered planes, such as 6, 8 or 12, etc., and these planes have a consistent slight taper along the axial direction for seamless splicing; Furthermore, the frustum-shaped mating hole 11 is a regular octagonal frustum-shaped hole, and the frustum-shaped mandrel 21 is a regular octagonal frustum-shaped mandrel that is adapted to the frustum-shaped mating hole 11.

[0026] Specifically, such as Figure 5 As shown, end face meshing teeth 6 are machined on the mating end faces of two adjacent spiral cutter sleeve modules 1. After axial clamping, the two adjacent end face meshing teeth 6 mesh with each other, which can more accurately ensure the circumferential phase between the two adjacent spiral cutter sleeve modules 1 and participate in the transmission of extremely large torque, further ensuring circumferential positioning and torque transmission.

[0027] In summary, this invention decomposes large and complex components into multiple small, standard modules, which greatly reduces the difficulty and cost of blank preparation, machining, and heat treatment. It has a high yield rate. When a local cutting edge is damaged, it is only necessary to loosen the hydraulic nut 5 and replace the damaged single or several spiral tool sleeve modules 1, realizing low-cost and rapid on-site repair and avoiding overall scrapping. Multiple spiral tool sleeve modules 1 are precisely connected by end face meshing teeth 6, which are seamless on a macroscopic scale. Like the integral structure, it can effectively prevent entanglement. The rigidity and reliability of the conical self-locking connection far exceed that of the traditional key connection, and there is no loosening problem.

[0028] A manufacturing process for a spiral blade crusher is disclosed. This process aims to solve the problems of large deformation during heat treatment of the integral blade shaft, easy peeling of the hard coating, and insufficient reliability of modular blade shaft connections in existing technologies. The process includes three main stages: preparation of the spiral blade sleeve module, preparation and pretreatment of the frustum mandrel, and stress-coordinated assembly and activation. The details are as follows: Phase 1: Preparation of the spiral cutter sleeve module Step S1: Near-net-shape forming and sintering of powder metallurgy The blank of the tool holder module with an internal composite material structure is directly manufactured using metal injection molding (MIM) or spark plasma sintering (SPS) technology. Specific operations: 1.1- Two powders were prepared: Powder A was a high-hardness, high-wear-resistant tungsten carbide-cobalt (WC-Co) cemented carbide, and Powder B was a high-toughness alloy steel powder (such as M2 high-speed steel powder). 1.2 Gradient filling: In the mold, first fill with powder A to form the cutting edge area of ​​the spiral blade module (about 3-5mm deep from the top of the spiral ridge to below), and then fill with powder B to form the blade base and inner hole area; 1.3-Integrated sintering: In MIM or SPS equipment, by precisely controlling the temperature and pressure fields, two powders diffuse and bond at the interface to achieve a gradient material structure of metallurgical fusion, which replaces traditional casting, forging and surface welding. Step S2: Simultaneous dual-medium quenching The sintered gradient material tool holder is subjected to directional selective quenching; Specific operations: The hot spiral tool sleeve module is rapidly cooled (gas quenching) by immersing its cutting edge area in a high-pressure nitrogen cooling chamber to prevent cracking. At the same time, its base and inner hole areas are quenched through a controllable oil cooling system. This process enables different areas of a single workpiece to achieve optimal heat treatment results in a single operation: the cutting edge reaches an extremely high hardness of HRC65 or higher, the matrix maintains a toughness of HRC45-50, and the deformation of the inner hole area is minimal. Step S3: Magnetic field assisted precision grinding A strong magnetic field is introduced into the grinding process to control the flow of grinding fluid and the discharge of grinding chips; Specific operations: 1.1- When precision grinding the inner hole of a multi-faceted pyramid, the workpiece is placed in a strong constant magnetic field and a special grinding fluid mixed with magnetic nanoparticles (such as iron oxide) is used. The magnetic field will guide the grinding fluid to accurately cover the contact area between the grinding wheel and the workpiece and quickly "pull" the grinding debris away from the processing area. This method can significantly reduce grinding heat, reduce surface burns, and improve the surface quality and dimensional accuracy of the inner hole facets; Phase Two: Preparation and Pretreatment of the Frustum Mandrel Step T1: Deep rolling and shot peening combined strengthening Composite surface strengthening is applied to the precision-machined multi-faceted pyramidal surface of the mandrel; Specific operations: 1.1 - First, a rolling head made of ultra-hard material is used to deeply roll each facet of the mandrel, introducing a huge residual compressive stress layer about 0.5 mm below the surface; 1.2 - Using microparticle shot peening technology to treat the same surface further optimizes the surface stress distribution and reduces roughness; This composite process doubles the fatigue strength and wear resistance of the mandrel surface, greatly enhancing its resistance to fretting wear. Phase 3: Stress-Coordinated Assembly and Activation Step A1: Temperature Difference Assembly and Prestress Generation By utilizing the differences in the coefficients of linear expansion of different materials, beneficial prestress is actively generated during the assembly process; Specific operations: 1.1-Cool the frustum mandrel in a liquid nitrogen environment to -80°C to -100°C to allow it to fully shrink; 1.2 - Heat the spiral blade sleeve module evenly in a heating furnace to 150°C-200°C to allow it to fully expand; 1.3- In an adiabatic environment, the cooled mandrel is quickly installed into the heated spiral tool holder module. After both return to room temperature, since the linear expansion coefficient of the mandrel is usually slightly greater than that of the tool holder base, the "rebound expansion" of the mandrel will be slightly greater than that of the tool holder, thus automatically generating some additional radial compressive stress on the contact surface. This stress is superimposed with the subsequent mechanical preload. Step A2: Torque-Displacement Dual Control Preload The preload process of the hydraulic nut is controlled by both torque and displacement standards to ensure the accuracy and consistency of the preload force. The hydraulic nut mainly consists of the following components: Hydraulic nut body: a high-strength annular component fitted onto the threaded end of the mandrel, which integrates one or more hydraulic piston chambers inside; High-strength tie rod: It is fitted onto the outside of the frustum mandrel, with one end fixed to the shoulder of the large end of the mandrel and the other end connected to the hydraulic nut; Hydraulic pump station: Connected to the hydraulic nut body via a high-pressure hose, it can accurately output and control hydraulic pressure; High-precision displacement sensor: Employs non-contact (such as an eddy current sensor) or contact (such as a dial indicator) sensor to accurately align and measure the axial displacement of the small end of the mandrel relative to a fixed reference point (such as the end face of the last tool sleeve module). Specific operations: 1.1 Place the cutter shaft assembly that has been assembled with temperature difference on the assembly platform, and firmly fix one end of the high-strength tie rod to the large end of the spindle; 1.2- Screw the hydraulic nut body into the thread of the small end of the mandrel and connect it to the other end of the pull rod, ensuring that the hydraulic nut is parallel and in contact with the end face of the mandrel; 1.3 Connect the hydraulic lines, install the displacement sensor, and align its probe with the center of the small end of the spindle or a dedicated measuring plane, and zero the sensor reading; 1.4 - Start the hydraulic pump station and slowly and evenly apply pressure to the hydraulic nut body. Monitor the pressure value of the hydraulic system in real time. This pressure value is converted into axial preload through the piston area of ​​the hydraulic nut. When the pressure value reaches 70% of the pressure value corresponding to the calculated target preload, stop pressurizing and hold the pressure for 30 seconds to allow the system stress to stabilize initially. Through mature hydraulic technology, a large base preload is applied quickly and accurately, eliminating most of the macroscopic gaps and allowing the components to enter the elastic deformation zone.

[0029] 1.5 - After holding the pressure at 70% of the corresponding pressure value, record the reading D1 of the displacement sensor at this time. Continue to slowly increase the hydraulic pressure. At this time, shift your attention completely from the pressure gauge to the reading of the displacement sensor. Record the displacement change ΔD for each small increment of pressure. As the pressure increases, the displacement D1 should increase linearly. Continue to pressurize until the cumulative displacement reaches the theoretical elastic elongation D2 calculated based on the elastic modulus, cross-sectional area and effective length of the mandrel material. Once D1≥D2, immediately stop pressurizing and tighten the mechanical locking component of the hydraulic nut. This stage directly controls the essential parameters: the ultimate goal of axial preload is to make the mandrel produce a specific elastic elongation, thereby obtaining a definite clamping force. This process bypasses the indirect and uncertain conversion chain of "pressure-friction-preload", and directly uses the essential physical quantity of elastic elongation as the criterion for termination judgment. It automatically compensates for errors caused by factors such as fluctuations in thread friction coefficient and changes in hydraulic system efficiency, ensuring the consistency of preload between different tool shaft products. This is something that the simple torque method or pressure method cannot achieve. 1.6 - After reaching the target displacement and mechanically locking, slowly release the hydraulic pressure to zero, remove the hydraulic line and displacement sensor. At this point, theoretically, the preload generated by the hydraulic system has been completely converted into the residual preload in the mechanical structure. You can apply pressure again slightly and check whether the displacement remains basically unchanged before the pressure starts to rise, to confirm that the mechanical locking is effective and the preload has not loosened significantly. Step A3: Pre-service micro-impact "acclimatization" After dynamic balancing verification, the assembled cutter shaft undergoes a special "taming" process. Specific operations: The cutter shaft is mounted on a test bench, and a series of low-energy, high-frequency random mechanical impacts are applied to its spiral blades at speeds far below normal operating speeds via a pneumatic device. This process aims to simulate slight impacts in actual working conditions, allowing the contact interface between modules to undergo initial micron-level wear and stress redistribution under controlled conditions, forming a more stable interface. This is equivalent to bringing the cutter shaft into its "optimal state" before it is officially put into service, improving the stability and lifespan of initial operation.

[0030] In summary, this preparation process employs powder metallurgy gradient composite material technology, which fundamentally resolves the contradiction between hardness and toughness, replacing the traditional homogeneous material + surface coating / welding solution. Simultaneous dual-medium quenching enables customized cooling of different regions of a single workpiece, overcoming the limitations of traditional single-medium quenching and balancing extreme hardness with low deformation. Magnetic field-assisted grinding improves the quality and efficiency of key internal hole machining, representing an innovation in the process. Temperature difference assembly generates prestress, torque-displacement dual-control pre-tightening, and micro-impact conditioning. These three elements together constitute a new and scientific assembly methodology, ensuring the ultimate reliability and consistency of the connection.

[0031] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A spiral blade shredder knife characterized by, The application relates to a spiral blade and a combined tool shaft. The spiral blade is composed of at least two hollow spiral blade sleeve modules (1) which are spliced in the axial direction, and the inner hole of the spiral blade sleeve module (1) is a prismatic matching hole (11). The combined tool shaft (2) penetrates the spiral blade and comprises a prismatic core shaft (21) matched with the prismatic matching hole (11), and the two ends of the prismatic core shaft (21) are provided with rotating shafts (22). One end of the prismatic core shaft (21) is provided with an axial positioning shaft shoulder (3), and the other end is provided with a locking mechanism for applying an axial pre-tightening force. The spiral blade sleeve module (1) is circumferentially limited by the taper surface matching of the prismatic matching hole (11) and the prismatic core shaft (21), and is tightly combined by the axial pre-tightening force applied by the locking mechanism, so as to transfer the torque by friction.

2. A spiral cutting knife according to claim 1, wherein The locking mechanism comprises an end cover (4) and a hydraulic nut (5) which are sequentially sleeved on the rotating shaft (22), the end cover (4) is pressed against the end surface of the spiral blade sleeve module (1), and the hydraulic nut (5) is used for applying an axial tension to the prismatic core shaft (21).

3. A spiral cutting knife according to claim 1, wherein The abutting end surfaces of the two adjacent spiral blade sleeve modules (1) are provided with end surface meshing teeth (6) which are meshed with each other.

4. A spiral cutting knife according to claim 1, wherein The cross section of the prismatic matching hole (11) and the prismatic core shaft (21) is a regular polygonal prism structure.

5. A spiral cutting knife according to claim 4, wherein The regular polygonal prism structure is a regular octagonal prism structure.

6. A manufacturing process for manufacturing a spiral cutting knife according to any one of claims 1-5, characterized in that, The preparation steps of the spiral blade sleeve module comprise the following steps: S1: adopting a powder metallurgy technology, a spiral blade sleeve module green body with a blade edge region and a base region composite material structure is prepared by gradient filling and integral sintering; S2: synchronous double-medium quenching is conducted on the sintered spiral blade sleeve module, so that the blade edge region and the base region obtain different hardness and toughness.

7. The process for manufacturing a spiral cutting knife according to claim 6, characterized in that, In step S1, the gradient filling is specifically that high-hardness wear-resistant material powder is first filled in a mold to form a blade edge region, and then high-toughness alloy steel powder is filled to form a base region and an inner hole region.

8. The process for manufacturing a spiral blade according to claim 6, characterized in that, In step S2, the synchronous double-medium quenching is specifically that the blade edge region of the spiral blade sleeve module is air quenched when the spiral blade sleeve module is hot, and the base region and the inner hole region are oil quenched.

9. The process for manufacturing a spiral cutting knife according to claim 6, characterized in that, After the preparation steps of the spiral blade sleeve module, an assembling step is further included, and the assembling step comprises the following steps: Step one: the prismatic core shaft (21) is subjected to deep rolling and shot blasting composite strengthening treatment; Step two: the spiral blade sleeve module (1) is sleeved on the prismatic core shaft (21) by using a temperature difference method; Step three: a hydraulic nut (5) is used for torque-displacement double-control pre-tightening of the assembled body.

10. The process for manufacturing a spiral cutting knife according to claim 9, characterized in that, Step A3 specifically comprises the following steps: an initial pre-tightening force is first applied through a hydraulic system, and then the elastic elongation of the prismatic core shaft (21) reaches a predetermined value as a judgment standard for terminating pre-tightening.

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