Cavity inlet structure and continuous extruder

Abstract

The application discloses a cavity material inlet structure and a continuous extruding machine, and relates to the technical field of continuous extruding forming equipment. The cavity material inlet structure comprises a cavity and an inlay body arranged at a material inlet of the cavity. The inlay body comprises at least two layers of inlay blocks which are sequentially sleeved from inside to outside. The innermost inlay block is provided with a material inlet channel which is communicated with the cavity. The thickness of each layer of the inlay blocks from inside to outside along the radial direction of the material inlet channel is sequentially increased, and the inlay blocks of adjacent two layers are in interference fit. The interlayer interface of the multilayer inlay blocks is crack stopping. When the crack is generated on the working surface of the innermost layer and expands to the interlayer interface, the crack deflects, branches, is passivated or even stops due to the assembly gap and thickness difference of the inlay blocks of adjacent two layers, and cannot penetrate the next layer.

Description

Technical Field

[0001] This invention relates to the field of continuous extrusion molding equipment technology, specifically to a cavity feed port structure and a continuous extruder. Background Technology

[0002] Continuous extrusion presses are the core equipment for forming metal profiles, pipes and other products. The cavity is a key component that bears the extrusion load and restricts the flow of metal. In particular, medium and large continuous extrusion presses have large cavity dimensions and extremely high working loads. During operation, they are accompanied by intense thermo-mechanical coupling cycles and are subjected to erosion and wear of metal materials as well as alternating shear stress. This makes the cavity inlet the most vulnerable area, which in turn affects the normal operation, service life and production efficiency of the entire machine.

[0003] Currently, the wear-resistant structures of the feed inlet of existing continuous extrusion press cavities are mainly divided into two types: one is an integral structure, in which the entire cavity is machined from hot-work die steel such as H13 steel. Although this structure is easy to process, the wear resistance and crack resistance of the feed inlet area are insufficient, making it prone to rapid wear and cracking, leading to the scrapping of the entire cavity and extremely high maintenance costs; the other is a single-piece structure, in which a high-strength wear-resistant material is inlaid around the feed inlet to improve the wear resistance and crack resistance of the feed inlet. However, this structure still has the following prominent defects: 1. Severe thermal stress concentration: The thermal expansion coefficients of the single high-strength wear-resistant material and the H13 steel substrate are very different. During operation, the temperature difference between the inside and outside of the insert is large and the peak value of the interface thermal stress is high, which can easily lead to problems such as the insert debonding from the substrate and the insert cracking itself. 2. Severe failure mode: The single insert is made of homogeneous material. Once a crack appears on the working surface, the crack will rapidly destabilize and propagate within the material, causing the entire insert to collapse. This is a sudden and catastrophic failure. Not only will the insert need to be replaced, but it may also damage the cavity matrix, causing unplanned downtime and huge economic losses. 4. Short fatigue life: The thermal fatigue limit of a single piece of brittle high-strength material is low. Under alternating loads and temperature cycles, thermal cracking is likely to occur, further shortening the service life of the insert. 5. Lack of effective pre-tightening protection: The existing structure does not use interference fit calculation to design pre-tightening force. During operation, the cavity inlet is subjected to compressive load and thermal stress, which will generate outward tensile force, which can easily cause the insert and the base to loosen, aggravate wear and cracking, and further shorten the service life.

[0004] Therefore, it is necessary to develop and design the cavity feed port structure and continuous extruder to avoid overall collapse, which is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides a cavity feed port structure and a continuous extruder, which achieves stress dispersion and interface crack prevention, enabling the inserts to fail in a progressive, layer-by-layer manner and avoiding overall collapse.

[0006] To achieve the above objectives, the present invention provides the following solution: A cavity inlet structure includes a cavity and a soil body disposed at the inlet of the cavity. The soil body includes at least two layers of inserts arranged sequentially from the inside to the outside. The innermost insert is provided with an inlet channel communicating with the cavity. The thickness of each layer of inserts increases sequentially along the radial direction of the inlet channel from the inside to the outside, and the inserts of adjacent layers are interference-fitted.

[0007] In one embodiment, the inserts in each layer are made of the same material or different materials.

[0008] In one embodiment, the cavity has an inlet for receiving the insert, and the outlet of the soil abuts against the bottom of the inlet.

[0009] In one embodiment, the hardness of the insert gradually decreases from the inner layer to the outer layer.

[0010] In one embodiment, the soil body includes three layers of inserts: an outer insert, a middle insert, and an inner insert. The inner insert is made of cemented carbide, the middle insert is made of tungsten carbide-cobalt cemented carbide transition alloy, and the outer insert is made of H13 modified steel.

[0011] In one embodiment, the middle insert has a limiting protrusion at its outlet end, and the outlet end of the inner insert abuts against the limiting protrusion.

[0012] The present invention also discloses a continuous extruder, including a feeding mechanism and the above-described cavity inlet structure. The feeding mechanism is used to convey rod material to the inlet of the cavity of the cavity inlet structure and to allow the rod material to pass through the feed channel of the cavity inlet structure.

[0013] In one embodiment, the feeding mechanism includes a frame for supporting the cavity, a mandrel disposed on the frame, an extrusion wheel disposed on the mandrel, a compaction wheel disposed on one side of the extrusion wheel and extruding the rod material together with the extrusion wheel, and a baffle block disposed on the frame for guiding the rod material into the cavity.

[0014] In one embodiment, the machine also includes a shoe holder, which is disposed on the frame and the cavity is disposed on the shoe holder. A clamping cylinder is also disposed on the frame, the output end of which is connected to the shoe holder. The clamping cylinder is used to adjust the distance between the cavity and the extrusion roller.

[0015] In one embodiment, the extrusion roller has a groove for accommodating the rod material, one end of the stop block extends into the groove, and the other end of the stop block is connected to the shoe seat.

[0016] In one embodiment, a guide plate for guiding the rod material is further provided between the shoe seat and the extrusion wheel.

[0017] In one embodiment, the frame is provided with a scraper for scraping material from the outer wall of the extrusion roller.

[0018] In one embodiment, the insert is adapted to the extrusion surface of the extrusion wheel.

[0019] The present invention achieves the following technical effects compared to the prior art: By incorporating multiple layers of inserts with increasing thickness from the inside out and an interference fit at the feed inlet, the gradient thickness design significantly enhances the overall structural strength and impact resistance, effectively resisting the severe compression and wear during rod feeding. Furthermore, when the inner and outer layers of the interference fit inserts experience fatigue or wear under long-term high-temperature and high-pressure conditions, only a single worn layer can be quickly replaced without scrapping the entire cavity, greatly reducing maintenance costs and downtime. Simultaneously, the tight interference fit between each layer ensures positioning accuracy and eliminates material leakage, thereby guaranteeing the long-term stability of the rod guiding and forming process. The product boasts high precision, and the interlayer interfaces of the multi-layer inserts all serve to prevent cracking. After a crack initiates on the innermost working surface, when it extends to the interlayer interface, due to differences in assembly gaps, thickness (when the materials are the same), or material properties (when the materials are different), the crack may deflect, bifurcate, become blunt, or even stop cracking, preventing it from penetrating to the next layer. Only when the innermost insert is completely worn and fails to bear the load can the second insert begin to bear the main load, and so on. This completely changes the failure mode of sudden overall collapse of a single insert, achieving layer-by-layer failure without total damage. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Appendix Figure 1 This is a schematic diagram of the overall structure of the continuous extruder disclosed in one or more embodiments of the present invention; Appendix Figure 2 This is a schematic diagram of the overall structure of the cavity inlet structure disclosed in one or more embodiments of the present invention; Appendix Figure 3 This is a three-dimensional structural diagram of the cavity inlet structure disclosed in one or more embodiments of the present invention. The components are as follows: 1. Scraper; 2. Rod; 3. Frame; 4. Extrusion Roller; 5. Mandrel; 6. Drive Pin; 7. Compactor Roller; 8. Guide Plate; 9. Guide Plate; 10. Shoe Seat; 11. Clamping Cylinder; 12. Cavity; 13. Mold; 14. Product; 15. Cavity Cover; 121. Cavity Body; 122. Stop Block; 124. Outer Insert; 125. Middle Insert; 126. Inner Insert. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The purpose of this invention is to provide a cavity feed port structure and a continuous extruder to achieve stress dispersion and interface crack prevention, so that the insert exhibits progressive failure layer by layer, avoiding overall collapse.

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 refer to Figures 2-3The cavity inlet structure disclosed in this embodiment of the invention includes at least a cavity 12. An insert is provided at the inlet of the cavity 12. The insert includes at least two layers of inserts, which are nested sequentially from the inside out. The innermost insert has an inlet channel with a diameter smaller than the preset diameter of the rod 2, so as to compress the rod 2 passing through it to the preset diameter, thereby compressing the rod 2 passing through the inlet channel into a blank with the same diameter as the preset diameter. The thickness of each layer of inserts increases sequentially from the inside out along the radial direction of the inlet channel. Adjacent inserts are interference-fitted. By providing multiple layers of inserts with increasing thickness from the inside out and interference fit at the inlet, the overall structural strength and impact resistance are significantly enhanced by the gradient thickness design, effectively resisting the severe compression and wear during the introduction of the rod 2. Moreover, when the interference-fitted inner and outer inserts 124 experience fatigue or wear under long-term high temperature and high pressure conditions... After damage, a single worn layer can be quickly replaced without scrapping the entire cavity 12, significantly reducing maintenance costs and downtime. At the same time, the tight interference fit between each layer ensures positioning accuracy and eliminates material leakage, thereby ensuring the long-term stability and product accuracy of the rod material 2 guiding and forming. Moreover, the interlayer interfaces of the multi-layer inserts can all play a crack-stopping role. After the crack initiates on the innermost working surface, when it extends to the interlayer interface, due to the assembly gap, thickness difference (when the materials are the same) or material performance difference (when the materials are different) between adjacent inserts, the crack will deflect, bifurcate, become blunt, or even stop cracking, and cannot penetrate to the next layer. Only when the innermost insert 126 is completely worn and fails to bear the load will the second insert begin to bear the main load, and so on. This completely changes the failure mode of sudden overall collapse of a single insert, achieving layer-by-layer failure without total damage.

[0026] In addition, the cavity 12 includes a cavity mother body 121 and a through-cavity formed on the cavity mother body 121. The cavity mother body 121 is used to fit around the outer periphery of the insert, so that the insert is accommodated in the cavity. The multi-layer insert adopts a nested interference fit design and is not integrally formed with the cavity mother body 121. Regardless of whether the same or different materials are used, due to the crack-stopping effect of the interlayer interface, cracks will not penetrate to the outer insert 124 and the cavity mother body 121. Therefore, if the first layer is damaged, it can be replaced in time without replacing other layers of inserts or the cavity mother body 121, and there is no need to disassemble the core components of the whole machine. At the same time, it completely solves the fatal defect of the existing single insert structure, which causes the cavity mother body 121 to be damaged and the mother body to be scrapped after cracking. It effectively protects the cavity mother body 121 and significantly reduces maintenance costs and equipment wear and tear.

[0027] refer to Figures 1-3 In one embodiment, a cavity cover 15 is provided at the end of the cavity 12 away from the feed inlet to limit the cavity body 121.

[0028] It should be noted that the thickness of adjacent inserts is calculated and designed based on the standard Lamé formula for the axisymmetric problem of thick-walled cylinders. The interference between each layer of inserts is calculated and optimized based on the classical solution of interference fit of thick-walled cylinders and Lamé formula. Through the interference calculated by this optimization, the multi-layer inserts at the feed inlet of cavity 12 generate a pre-tightening force after being assembled with cavity 12. The pre-tightening force is used to counteract the outward tensile force generated by the inlet of cavity 12 due to the extrusion load and thermal stress during the operation of the equipment, so as to avoid loosening between layers and deformation of the inlet of cavity 12. The classic solution for interference fit of thick-walled cylinders is as follows: For an inner cylinder with inner and outer radii of r1 and r2 respectively, and an outer cylinder with inner and outer radii of r2 and r3 (i.e., the inner and outer radii when the insert is cylindrical), the interference is δ (i.e., the difference between the outer diameter of the inner cylinder and the inner diameter of the outer cylinder). The radial pressure p on the contact surface can be obtained by the following formula: Summarized as follows: To match the diameter , , , The elastic modulus and Poisson's ratio of the inner cylinder material , The elastic modulus and Poisson's ratio of the outer cylinder material Lamé's formula: Indicates radial stress. Indicates circumferential stress This indicates the pressure exerted on the inner surface. Indicates the pressure on the outer surface Indicates the inner radius of the cylinder. denoted by r, where r represents the outer radius of the cylinder and r represents the current radius of the stress point to be determined.

[0029] Thickness calculation for each layer of inserts: The thickness and assembly tightness (interference allowance) are repeatedly adjusted and optimized. The general process is as follows: First, determine the fixed conditions: feed inlet size, cavity mounting hole size (total wall thickness is fixed), working pressure, working temperature, and materials selected for each layer.

[0030] Estimate the initial thickness: Based on the rule that the inner layer is the thinnest, the middle layer is in the middle, and the outer layer is the thickest, give a set of initial dimensions (the thickness ratio of a 3-layer structure is usually between 1:1:1.5 and 1:1.2:2).

[0031] Calculate the preload after assembly: Based on the classical solution of interference fit of thick-walled cylinder, calculate the preload generated inside each layer after compression assembly.

[0032] Calculate the total stress during operation: Based on Lamé's formula, the pre-compression stress, working extrusion pressure, and thermal stress generated by thermal expansion and contraction are superimposed to check whether the maximum stress of each layer exceeds the material's bearing limit.

[0033] Repeated iterative optimization: Adjust the thickness and assembly tightness, repeat the above calculations until the following conditions are met simultaneously: each layer does not exceed the material's bearing limit, the inner layer fails first, the interlayer stress is stable, the preload can offset the external support tension, and the processing and usage requirements are met.

[0034] 1. Different material options Inner insert 126: Made of the hardest, most wear-resistant, and most extrusion-resistant material, it is therefore the thinnest. The thin inner layer allows the preload to be transmitted to the working surface more efficiently, and better counteracts the tension of the external support; at the same time, the thickness only needs to meet the wear life requirements, without wasting high-performance materials by making it too thick.

[0035] Intermediate insert 125: Made of a material with moderate toughness and performance between the inner and outer layers, with a moderate thickness. Its core function is to buffer stress and bridge the gap between thermal expansion and contraction, preventing excessive differences in the performance of the inner and outer layers, which could lead to stress concentration at the joint and easy separation.

[0036] Outer insert 124: Made of a material with slightly lower strength but similar thermal expansion properties to cavity 12, hence the thickest. Because the material has slightly weaker load-bearing capacity, a thicker layer is necessary to ensure structural strength; at the same time, the thicker outer layer adheres more stably to the substrate, can evenly transmit preload, and is less prone to loosening.

[0037] 2. Same material scheme When using the same material throughout, the principle of thinner inner layers and thicker outer layers still applies: the inner layer is thinner, has a higher stress level, and bears wear and load first, thus failing first; the outer layer is thicker, has a lower stress level, bears load later, and fails later. By dispersing stress through thickness differences and combining this with interlayer interface crack arrest, the same effect of progressive failure can be achieved, and the process is simpler and less costly.

[0038] After the theoretical calculations are completed, these engineering requirements must also be met: The wear resistance life requirement for the inner layer insert 126 is as follows: the radial thickness of the inner layer must be greater than the total wear within the expected life, with an additional safety margin of 3mm to 5mm, to avoid the stress calculation being qualified but the insert being worn through quickly in actual use.

[0039] Minimum wall thickness requirement: The absolute thickness of a single layer shall not be less than 3mm to 5mm, and shall not be less than 1 / 20 to 1 / 15 of the fitting diameter, in order to prevent deformation and cracking during hot assembly.

[0040] Thermal stress matching requirements: The greater the difference in the thermal expansion coefficients of two adjacent layers, the greater the thickness of the intermediate transition layer needs to be to alleviate the peak thermal stress at the operating temperature and avoid interlayer debonding.

[0041] Interference fit matching requirements: The greater the interference fit of the assembly (the tighter it is assembled), the greater the supporting force on the outer layer, and the corresponding outer layer wall thickness should be increased accordingly to prevent the outer layer from cracking directly during assembly.

[0042] By accurately calculating the interference amount using the Lamé formula and the classical solution of interference fit for thick-walled cylinders, a stable pre-tightening force (pre-shrinkage force) is generated at the inlet of cavity 12. This force can precisely counteract the outward tensile force generated at the inlet of cavity 12 due to extrusion load and thermal stress during operation, preventing interlayer loosening, debonding, and deformation of the inlet of cavity 12, thereby further improving structural stability and extending the service life of the insert and the whole machine.

[0043] In one embodiment, each layer of inserts is made of different or the same material. Each layer of inserts can be flexibly made of the same or different materials according to the working conditions. Homogeneous materials can be used to simplify spare parts management and achieve balanced wear, or materials can be selected separately for different needs such as high temperature friction of the inner layer and pressure support of the outer layer, so as to achieve a precise match between performance and cost.

[0044] The following table shows the specific parameters of the three-layer inlay: Table 1 Parameters of 800 Three-Layer Composite Patch

[0045] In the table above, the inner layer insert 126 has an outer diameter of 80mm and an interference fit with the middle layer of 0.35-0.4mm; the middle layer insert 125 has an outer diameter of 106mm and an interference fit with the outer layer insert 124 of 0.4-0.45mm; the inner layer insert 126 (the feed port is equivalent to a circular hole with a radius of 28mm) is made of GH4169.

[0046] refer to Figures 2-3In one embodiment, the inlet of the cavity 12 is provided with a receiving groove for accommodating the insert. The outlet end of the insert in the inner layer abuts against the bottom of the receiving groove. The receiving groove provides a precise radial and axial positioning reference for each layer of inserts. When a local insert is worn, it can be quickly disassembled and replaced based on the positioning reference of the receiving groove without damaging the cavity 12, which greatly reduces the difficulty and cost of maintenance. At the same time, the flexible adaptability of this structure to different materials makes it possible to combine the inner wear-resistant material with the outer high-strength material, further optimizing the overall performance throughout the entire life cycle.

[0047] As one implementation method, the hardness of the insert gradually decreases from the inside to the outside. By designing the inlet insert as a three-layer gradient composite system and selecting different materials for each layer under different working conditions, a synergistic optimization of performance and cost is achieved. As a preferred embodiment, the insert is configured in three layers: an outer insert 124, a middle insert 125, and an inner insert 126.

[0048] The inner insert 126 is made of cemented carbide, the middle insert 125 is made of WC-Co (tungsten carbide-cobalt cemented carbide) transition alloy, and the outer insert 124 is made of H13 modified steel. The high-frequency impact and severe abrasive wear of the inner cemented carbide straight rod 2 during introduction, its extremely high hardness and compressive strength provide a precise and durable wear-resistant working surface for guiding and forming, effectively extending the service life of the core area; the middle WC-Co transition alloy, as a gradient buffer layer, has a coefficient of thermal expansion and elastic modulus between cemented carbide and mold 13 steel, which can effectively alleviate the thermal mismatch stress caused by the difference in physical properties between the inner and outer layers under high temperature conditions, and at the same time, it absorbs the impact vibration energy with its good toughness, preventing the brittle inner layer from cracking under heavy load; the outer H13 modified steel, as the structural load-bearing matrix, provides reliable support and clamping force for the entire insert assembly with its excellent high-temperature red hardness and fatigue resistance, and ensures a precise fit with the cavity receiving groove with its good machinability.

[0049] In one implementation, the discharge end of the intermediate insert is provided with a limiting protrusion, and the discharge end of the inner insert abuts against the fiber protrusion. That is, the intermediate insert 125 is set in an L-shape, and the inner insert 126 abuts against the intermediate insert 125. The abutting design at the end of the inner insert 126 effectively constrains the huge axial impact force generated during the extrusion of the rod material 2, preventing the insert from shifting or falling off in the feeding direction, and fundamentally ensuring the centering and dimensional accuracy of the guiding molding.

[0050] Example 2 refer to Figures 1-3This embodiment also discloses a continuous extrusion press, including a feeding mechanism and the cavity inlet structure in Embodiment 1. The feeding mechanism is used to transport and pass the rod material 2 through the inlet channel of the cavity inlet structure.

[0051] The feeding mechanism includes a frame 3 for supporting the cavity 12. A mandrel 5 is mounted on the frame 3. The mandrel 5 is driven to rotate by a motor and a reducer. An extrusion roller 4 is connected to the mandrel 5. The extrusion roller 4 is driven to rotate by the mandrel 5. A compaction roller 7 is mounted on one side of the extrusion roller 4. The extrusion roller 4 and the compaction roller 7 together extrude the rod material 2. A stop block 122 is mounted on the frame 3 to guide the rod material 2 into the cavity 12. The multi-layer interference fit and end abutment limiting structure ensure the axial and radial positioning reliability of the insert under the alternating load generated by the continuous rotation of the extrusion roller 4, preventing it from moving and falling off. It also allows for quick layer replacement after local wear of the insert, without having to replace the entire cavity 12 or the frame 3, significantly reducing maintenance costs and downtime.

[0052] In one implementation, the insert is adapted to the extrusion surface of the extrusion wheel 4, that is, the contact surface between the insert and the extrusion surface is consistent with the curvature of the extrusion surface. A multi-layer insert system is set at the feed port, which is precisely adapted to the extrusion surface of the extrusion wheel 4 to ensure the guiding accuracy of the rod material 2.

[0053] It should be noted that the mandrel 5 and the extrusion wheel 4 are connected by the transmission pin 6.

[0054] refer to Figures 1-3 As one embodiment of this invention, it also includes a shoe holder 10, which is mounted on the frame 3, and the cavity 12 is mounted on the shoe holder 10. The frame 3 is also equipped with a clamping cylinder 11, the output end of which is connected to the shoe holder 10. The clamping cylinder 11 is used to adjust the distance between the cavity 12 and the extrusion wheel 4. The shoe holder 10 firmly supports the cavity 12 on the frame 3, and the output end of the clamping cylinder 11 is directly connected to the shoe holder 10. It can actively adjust the mating distance between the cavity 12 and the extrusion wheel 4 according to process requirements. It can not only achieve precise alignment and gap adjustment during initial installation to ensure that the extrusion surface of the multi-layer insert and the working surface of the extrusion wheel 4 reach the best fit and improve the guiding and forming accuracy, but also provide online dynamic compensation for gap changes caused by insert wear or thermal expansion during long-term continuous operation, maintain constant extrusion pressure and sealing effect, and effectively prevent material leakage or extrusion pressure fluctuation.

[0055] refer to Figure 1As one implementation method, the extrusion roller 4 is provided with a groove for accommodating the rod material 2. One end of the baffle block 122 extends into the groove, and the other end of the baffle block 122 is connected to the shoe seat 10. The groove on the extrusion roller 4 provides a circumferential constraint channel for the rod material 2. One end of the baffle block 122 extends precisely into the groove, and the other end is fixedly connected to the shoe seat 10, thus constructing a closed-loop positioning system from the frame 3 to the shoe seat 10 to the baffle block 122 and then to the groove of the extrusion roller 4. This not only ensures that the rod material 2 is accurately guided into the cavity 12 along a predetermined trajectory under the drive of the rotating extrusion roller 4, avoiding the rod material 2 from falling out or deviating, but also utilizes the cooperation between the baffle block 122 and the groove to form a scraping effect, effectively preventing the residual material adhering to the surface of the extrusion roller 4 from entering the non-working area with the rotation, thus ensuring the continuity and purity of the feeding.

[0056] refer to Figure 1 As one implementation method, a guide plate 9 for guiding the rod material 2 is also provided between the shoe seat 10 and the extrusion wheel 4. The guide plate 9 is fixed on the shoe seat 10 by the guide plate pressure plate 8. The guide plate 9 added between the shoe seat 10 and the extrusion wheel 4 further assists in constraining and smoothly guiding the transition section of the rod material 2 into the groove at the front end of the baffle block 122, effectively eliminating the blind zone of guidance at the groove entrance of the baffle block 122 and the extrusion wheel 4, and preventing the rod material 2 from shifting, warping or getting stuck due to centrifugal force or vibration under high-speed rotation.

[0057] refer to Figure 1 In one embodiment, the frame 3 is provided with a scraper 1 for scraping the outer wall of the extrusion roller 4. The scraper 1 on the frame 3 scrapes the outer wall of the extrusion roller 4 in real time, effectively removing the residual material, oxide scale or impurities that adhere to the outer circumferential surface of the extrusion roller 4 during rotation, and preventing these deposits from being carried into the groove and cavity 12 entrance as the extrusion roller 4 rotates, thereby preventing foreign matter from entering and causing internal defects in the product or abnormal scratches on the working surface of the insert.

[0058] refer to Figure 1 In one implementation, the cavity 12 is provided with a mold 13 for forming the rod 2. The rod 2 enters the mold 13 inside the cavity 12 and is precisely formed to form the product 14. The mold 13 directly determines the final cross-sectional shape and dimensional accuracy of the product. Its close connection with the multi-layer inserts ensures the uniformity of pressure and temperature of the molten or softened rod 2 before entering the mold 13. Furthermore, the inserts buffer and transmit the extrusion pressure, preventing the mold 13 from directly bearing the alternating impact load generated by the rotation of the extrusion roller 4, thereby significantly extending the service life of the mold 13.

[0059] It should be noted that, for those skilled in the art, it is obvious that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A cavity inlet structure, characterized in that, The device includes a cavity (12) and an insert with an inlet in the cavity (12). The insert includes at least two layers of inserts arranged sequentially from the inside to the outside. The innermost insert has an inlet channel communicating with the cavity (12). The thickness of each layer of inserts increases sequentially from the inside to the outside along the radial direction of the inlet channel, and the inserts of adjacent layers are interference-fitted.

2. The cavity inlet structure according to claim 1, characterized in that, The inserts in each layer may be made of the same material or different materials.

3. The cavity inlet structure according to claim 1, characterized in that, The cavity (12) has an inlet for receiving the insert, and the outlet of the insert abuts against the bottom of the inlet.

4. The cavity inlet structure according to any one of claims 1-3, characterized in that, The hardness of the inserts gradually decreases from the inner layer to the outer layer.

5. The cavity inlet structure according to claim 4, characterized in that, The insert comprises three layers of inserts, namely an outer insert (124), a middle insert (125), and an inner insert (126). The inner insert (126) is made of cemented carbide, the middle insert (125) is made of tungsten carbide-cobalt cemented carbide transition alloy, and the outer insert (124) is made of H13 modified steel.

6. The cavity inlet structure according to claim 5, characterized in that, The discharge end of the intermediate insert (125) is provided with a limiting protrusion, and the discharge end of the inner insert (126) abuts against the limiting protrusion.

7. A continuous extrusion press, characterized in that, Includes a feeding mechanism and a cavity inlet structure as described in any one of claims 1-6, wherein the feeding mechanism is used to feed the rod material (2) into the inlet of the cavity (12) of the cavity inlet structure and to allow the rod material (2) to pass through the inlet channel of the insert of the cavity inlet structure.

8. The continuous extrusion press according to claim 7, characterized in that, The feeding mechanism includes a frame (3) for supporting the cavity (12), a mandrel (5) mounted on the frame (3), an extrusion wheel (4) mounted on the mandrel (5), a compaction wheel (7) mounted on one side of the extrusion wheel (4) and extruding the rod material (2) together with the extrusion wheel (4), and a baffle block (122) mounted on the frame (3) for guiding the rod material (2) into the cavity (12).

9. The continuous extrusion press according to claim 8, characterized in that, It also includes a shoe seat (10), which is disposed on the frame (3), and the cavity (12) is disposed on the shoe seat (10). The frame (3) is also provided with a pressing cylinder (11), the output end of which is connected to the shoe seat (10). The pressing cylinder (11) is used to adjust the distance between the cavity (12) and the extrusion wheel (4).

10. The continuous extrusion press according to claim 9, characterized in that, The extrusion wheel (4) has a groove for accommodating the rod material (2), one end of the baffle block (122) extends into the groove, and the other end of the baffle block (122) is connected to the shoe seat (10).

11. The continuous extrusion press according to claim 9, characterized in that, A guide plate (8) for guiding the bar stock (2) is also provided between the boot seat (10) and the extrusion wheel (4).

12. The continuous extrusion press according to claim 8, characterized in that, The insert is adapted to the extrusion surface of the extrusion wheel (4).

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