High toughness slewing ring by synergic multi-stage gradient heat treatment process and composition optimization

Abstract

This invention relates to the field of ball or roller bearing components, and discloses a high-toughness slewing bearing with synergistic multi-stage gradient heat treatment process and composition optimization. The bearing includes an outer ring, on the outer surface of which an external toothed ring is fixedly fitted. An mounting ring groove is formed on the upper side of the outer ring, and eight roller grooves are formed on the bottom wall of the mounting ring groove. Rollers are installed inside each of the eight roller grooves. A first inner ring and a second inner ring are installed on the inner side of the outer ring. Roller ring grooves are formed on the outer surfaces of both the first and second inner rings, and the two roller ring grooves are interconnected. The outer ring, the first inner ring, and the second inner ring are equipped with disassembly and assembly mechanisms, and sealing mechanisms are also provided on the outer ring, the first inner ring, and the second inner ring. These mechanisms form two sets of sealing surfaces, effectively preventing dust and debris from intruding into the bearing from the upper and lower sides. This avoids roller wear and raceway damage caused by seal failure in traditional single-seal structures, ensuring long-term stable operation.

Description

Technical Field

[0001] This invention relates to the field of ball or roller bearing parts technology, specifically to a high-toughness slewing bearing with synergistic multi-stage gradient heat treatment process and composition optimization. Background Technology

[0002] Synergistic multi-stage gradient heat treatment is an innovative metal heat treatment technology. By precisely controlling the heating and cooling processes at multiple temperature stages, a performance gradient distribution from the surface to the core is formed inside the material, giving the material both surface hardness and internal toughness. Composition-optimized high-toughness slewing bearings are high-end bearings manufactured using specific alloy ratios and advanced heat treatment processes. They can simultaneously withstand axial force, radial force, and overturning moment, and are widely used in engineering machinery, wind power equipment, and other fields, and are known as the joints of machines. As a core rotating component of large equipment such as engineering machinery, mining equipment, and port machinery, slewing bearings generally operate in environments with a large amount of dust, sand, debris, and other impurities. These impurities can easily penetrate through the sealing gaps and enter the interior of the slewing bearing, directly entering the mating area between the rollers and raceways, causing abrasive wear. The impurities scrape and squeeze between the rolling elements and raceways, not only damaging the surface precision of the raceways and rollers and increasing frictional resistance, but also causing faults such as raceway pitting and roller deformation. This leads to a decrease in the slewing accuracy of the slewing bearing, an increase in operating noise, and in severe cases, even jamming failure, significantly shortening the service life of the slewing bearing. Summary of the Invention

[0003] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a high-toughness slewing bearing with a synergistic multi-stage gradient heat treatment process and composition optimization. It can form two sets of sealing surfaces, effectively preventing dust and debris from entering the interior from the upper and lower sides of the bearing. This avoids roller wear and raceway damage caused by seal failure in traditional single-seal structures, ensuring long-term stable operation. (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a high-toughness slewing bearing with synergistic multi-stage gradient heat treatment process and composition optimization, including an outer ring, an outer toothed ring fixedly sleeved on the outer surface of the outer ring, an mounting ring groove opened on the upper side of the outer ring, and eight roller grooves opened on the bottom wall of the mounting ring groove, the eight roller grooves being arranged in a ring array. Rollers are installed inside each of the eight roller grooves, and a first inner ring and a second inner ring are installed on the inner side of the outer ring. The first inner ring and the second inner ring are arranged symmetrically from top to bottom. Roller ring grooves are formed on the outer surfaces of both the first inner ring and the second inner ring, and the interiors of the two roller ring grooves are connected. Eight rollers extend toward a portion of the first inner ring and the second inner ring into the inside of the roller annular groove. The outer ring, the first inner ring and the second inner ring are provided with a disassembly and assembly mechanism, which allows the first inner ring and the second inner ring to be quickly disassembled from the inside of the outer ring or installed on it. The disassembly and assembly mechanism includes six first countersunk holes, six nut grooves, six first countersunk bolts, six nuts, a mounting ring, four second countersunk holes, and four second countersunk bolts; Sealing mechanisms are provided on the outer ring, the first inner ring, and the second inner ring. These sealing mechanisms can block dust and other debris from entering the interior of the support. The sealing mechanism includes a first sealing ring groove, a second sealing ring groove, two connecting ring grooves, four connecting rings, four fixing rings, and four sealing rings. Preferably, all six first countersunk holes are formed on the upper side of the first inner ring, and the six first countersunk holes are arranged in a ring array; All six nut grooves are located on the lower side of the second inner ring, and the six nut grooves are arranged in a circular array. All six nut slots are hexagonal, and the six first countersunk bolts are respectively installed inside the six first countersunk holes. Preferably, the threaded portions of the six first countersunk bolts all extend into the interior of the nut grooves, the six nuts are respectively installed inside the six nut grooves, and the six first countersunk bolts are threadedly connected to the six nuts respectively. Preferably, the mounting ring is installed inside the mounting ring groove, and the four second countersunk holes are all opened on the upper side of the mounting ring, and the four second countersunk holes are arranged in a ring array. The four second countersunk bolts are respectively installed inside the four second countersunk holes, and the threaded portion of the four second countersunk bolts extends into the inner part of the outer ring. Preferably, the first sealing ring groove is formed on the upper side of the mounting ring, and the second sealing ring groove is formed on the lower side of the outer ring; Two connecting ring grooves are respectively formed on the outer surfaces of the first inner ring and the second inner ring, and the two connecting ring grooves are arranged symmetrically from top to bottom. Preferably, the four connecting rings are respectively installed inside two connecting ring slots, and two connecting rings are installed inside each connecting ring slot; The two connecting rings inside each connecting ring groove combine to form a complete circular ring, and the four fixing rings are fixedly connected to the four connecting rings on the sides that are far apart from each other. Preferably, the four fixing rings are respectively disposed in the gap between the outer ring and the first inner ring and the second inner ring, and the four sealing rings are respectively fixedly connected to the outer surface of the four fixing rings; Four sealing rings extend into the interior of the first sealing ring groove and the second sealing ring groove, respectively, and two sealing rings are installed inside the first sealing ring groove and the second sealing ring groove. The synergistic multi-stage gradient heat treatment process includes the following steps: S1: First, slowly preheat the slewing bearing substrate to 400-600℃ to eliminate initial stress, and then gradually increase the temperature to 850-950℃ through 2-4 temperature gradients to complete austenitization, avoiding microstructural defects caused by sudden temperature changes. S2: The quenching stage adopts a graded cooling strategy of first water cooling, then oil cooling, and finally air cooling to form a high-hardness hardened layer on the support surface with a Rockwell hardness value of 58-62 HRC, while retaining the tough core structure with a Rockwell hardness value of 38-45 HRC. S3: Finally, the slewing bearing undergoes multi-stage gradient tempering at 180℃, 250℃, and 350℃ to eliminate residual quenching stress, promote the formation of a composite microstructure of ultrafine grains, bainite, and retained austenite, and combine the composition optimization design of Ti and Nb microalloying in the substrate and rare earth element purification of grain boundaries to achieve a balance between surface hardness and internal toughness, significantly improving impact toughness and fatigue life. (III) Beneficial Effects Compared with the prior art, the present invention provides a high-toughness slewing bearing with synergistic multi-stage gradient heat treatment process and composition optimization, which has the following beneficial effects: (1) The high-toughness rotary bearing with multi-stage gradient heat treatment process and composition optimization forms two sets of sealing surfaces through the multi-coordinated sealing structure of connecting ring groove, connecting ring, fixed ring, sealing ring, first sealing ring groove and second sealing ring groove, which effectively blocks dust and debris from entering the interior from the upper and lower sides of the bearing, avoids the roller wear and raceway damage caused by the failure of the traditional single sealing structure, and ensures long-term stable operation. (2) The high-toughness slewing bearing with multi-stage gradient heat treatment process and composition optimization can quickly separate and assemble the inner ring assembly from the outer ring through the axial fastening system of the first countersunk bolt and nut and the auxiliary fixation of the second countersunk bolt and mounting ring. When disassembling, only the bolt needs to be unscrewed to separate the inner ring and the mounting ring, which solves the pain points of cumbersome disassembly and assembly and long maintenance time of traditional slewing bearings and greatly improves maintenance efficiency. (3) The high-toughness slewing bearing with synergistic multi-stage gradient heat treatment process and composition optimization forms a 58-62HRC high-hardness hardened layer on the surface and retains a 38-45HRC tough structure in the core through synergistic multi-stage gradient heat treatment process and composition optimization, achieving a composite performance of surface hardness and internal toughness. The synergistic effect of ultrafine grain, bainite and retained austenite structure significantly improves impact toughness and fatigue life, and solves the problem of uneven performance and easy cracking caused by the rough heat treatment process of traditional slewing bearings. (4) The high-toughness slewing bearing with multi-stage gradient heat treatment process and composition optimization, after heat treatment and composition optimization of the outer ring, the first inner ring and the second inner ring, the overall bearing base components have high toughness characteristics that can stably withstand axial force, radial force and overturning moment, avoiding early failure caused by stress concentration in traditional single inner ring structure. (5) The high-toughness slewing bearing with multi-stage gradient heat treatment process and composition optimization achieves convenient roller loading and unloading through the design of mounting ring groove and mounting ring. The roller groove on the bottom wall of the mounting ring groove provides a precise mounting reference for the roller. After the mounting ring is embedded, it is fixed by the second countersunk bolt to form a closed cavity. When disassembling, only the bolt needs to be unscrewed to remove the mounting ring, which exposes the opening of the roller groove. The roller can be directly taken out or installed along the axial direction without disassembling the outer ring or inner ring assembly, which greatly shortens the maintenance time and improves maintainability. Attached Figure Description

[0004] Figure 1 This is a schematic diagram of the high-toughness slewing bearing structure of the present invention, which combines multi-stage gradient heat treatment process with composition optimization; Figure 2 This is a schematic diagram of the connection structure at the outer ring of the present invention; Figure 3 This is a schematic diagram of the connection structure of the mounting ring of the present invention; Figure 4 This is a schematic diagram of the connection structure on the lower side of the outer ring of the present invention; Figure 5 This is a schematic diagram of the cross-sectional connection structure of the first inner ring and the second inner ring of the present invention; Figure 6 for Figure 5 Enlarged view of point A; Figure 7 This is a schematic diagram of the connection structure at the connecting ring of the present invention. In the diagram: 1. Outer ring; 2. External toothed ring; 3. Mounting ring groove; 4. Roller groove; 5. Roller; 6. First inner ring; 7. Second inner ring; 8. Roller ring groove; 9. First countersunk hole; 10. Nut groove; 11. First countersunk bolt; 12. Nut; 13. Mounting ring; 14. Second countersunk hole; 15. Second countersunk bolt; 16. First sealing ring groove; 17. Second sealing ring groove; 18. Connecting ring groove; 19. Connecting ring; 20. Retaining ring; 21. Sealing ring. Detailed Implementation

[0005] This section will describe in detail specific embodiments of the present invention. Preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the drawings is to supplement the textual description with graphics, so that people can intuitively and vividly understand each technical feature and overall technical solution of the present invention, but they should not be construed as limiting the scope of protection of the present invention. In the description of this invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention. In the description of this invention, terms such as greater than, less than, and exceeding are understood to exclude the stated number, while terms such as above, below, and within are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features. In the description of this invention, unless otherwise explicitly defined, terms such as "set up," "install," and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution. Please see Figures 1 to 7 This invention provides a novel technical solution: a high-toughness slewing bearing with synergistic multi-stage gradient heat treatment and composition optimization, comprising an outer ring 1, an external toothed ring 2 fixedly sleeved on the outer surface of the outer ring 1, a mounting ring groove 3 formed on the upper side of the outer ring 1, eight roller grooves 4 formed on the bottom wall of the mounting ring groove 3, the eight roller grooves 4 arranged in a circular array, and rollers 5 installed inside each of the eight roller grooves 4, a first inner ring 6 and a second inner ring 7 installed on the inner side of the outer ring 1, the first inner ring 6 and the second inner ring 7 arranged symmetrically, roller ring grooves 8 formed on the outer surfaces of the first inner ring 6 and the second inner ring 7, the interiors of the two roller ring grooves 8 being interconnected, and the eight rollers 5 extending towards a portion of the first inner ring 6 and the second inner ring 7 into the interior of the roller ring grooves 8, the outer ring... 1. The first inner ring 6 and the second inner ring 7 are provided with a disassembly and assembly mechanism, which can quickly remove or install the first inner ring 6 and the second inner ring 7 from the inside of the outer ring 1. The disassembly and assembly mechanism includes six first countersunk holes 9, six nut grooves 10, six first countersunk bolts 11, six nuts 12, mounting rings 13, four second countersunk holes 14 and four second countersunk bolts 15. The outer ring 1, the first inner ring 6 and the second inner ring 7 are provided with a sealing mechanism, which can block dust and other debris from the outside and prevent debris from entering the interior of the support. The sealing mechanism includes a first sealing ring groove 16, a second sealing ring groove 17, two connecting ring grooves 18, four connecting rings 19, four fixing rings 20 and four sealing rings 21. All six first countersunk holes 9 are located on the upper side of the first inner ring 6 and are arranged in a circular array. All six nut grooves 10 are located on the lower side of the second inner ring 7 and are arranged in a circular array. All six nut grooves 10 are hexagonal grooves. All six first countersunk bolts 11 are installed inside the six first countersunk holes 9, and the threaded portion of all six first countersunk bolts 11 extends into the nut groove 10. All six nuts 12 are installed inside the six nut grooves 10, and the six first countersunk bolts 11 are threadedly connected to the six nuts 12. The mounting ring 13 is installed inside the mounting ring groove 3. All four second countersunk holes 14 are located on the upper side of the mounting ring 13 and are arranged in a circular array. All four second countersunk bolts 15 are installed inside the four second countersunk holes 14, and the threaded portion of all four second countersunk bolts 15 extends into the outer ring 1. The first sealing ring groove 16 is formed on the upper side of the mounting ring 13, the second sealing ring groove 17 is formed on the lower side of the outer ring 1, and two connecting ring grooves 18 are respectively formed on the outer surfaces of the first inner ring 6 and the second inner ring 7. The two connecting ring grooves 18 are arranged symmetrically from top to bottom. Four connecting rings 19 are respectively installed inside the two connecting ring grooves 18. Two connecting rings 19 are installed inside each connecting ring groove 18. The two connecting rings 19 inside each connecting ring groove 18 are combined to form a complete ring. Four fixing rings 20 are respectively fixedly connected to the sides of the four connecting rings 19 that are far apart from each other. The four fixing rings 20 are respectively set in the gaps between the outer ring 1 and the first inner ring 6 and the second inner ring 7. Four sealing rings 21 are respectively fixedly connected to the outer surfaces of the four fixing rings 20. The four sealing rings 21 extend into the interior of the first sealing ring groove 16 and the second sealing ring groove 17. Two sealing rings 21 are installed inside the first sealing ring groove 16 and the second sealing ring groove 17. Furthermore, the outer ring 1 is the overall load-bearing base component, and the outer toothed ring 2 is fixedly sleeved on the outer surface of the outer ring 1 to transmit power to drive the overall rotation of the support. The mounting ring groove 3 of the outer ring 1 provides the mounting reference for the mounting ring 13. The eight annularly arrayed roller grooves 4 opened on the bottom wall of the mounting ring groove 3, together with the axially connected roller ring grooves 8 opened on the outer surfaces of the first inner ring 6 and the second inner ring 7, constitute the rolling channel of the rollers 5. The eight rollers 5 are respectively installed in the eight roller grooves 4, and partially extend into the interior of the roller ring grooves 8. When the outer ring 1 rotates relative to the first inner ring 6 and the second inner ring 7, the rollers 5 roll between the roller grooves 4 and the roller ring grooves 8, converting sliding friction into rolling friction and reducing motion resistance. At the same time, relying on the high toughness characteristics formed by the coordinated multi-stage gradient heat treatment and composition optimization of the outer ring 1, the first inner ring 6, and the second inner ring 7, they can stably withstand axial force, radial force, and overturning moment. The disassembly and assembly mechanism achieves rapid separation and assembly of the inner ring assembly and the outer ring 1 through bolt connection and positioning. During installation, the first inner ring 6 and the second inner ring 7 are symmetrically arranged on the inner side of the outer ring 1, so that the roller 5 is accurately embedded between the roller groove 4 and the roller ring groove 8. Then, six first countersunk bolts 11 are respectively inserted into the six annular array of first countersunk holes 9 opened on the upper side of the first inner ring 6, so that the threaded part of the first countersunk bolt 11 extends into the six annular array of hexagonal nut grooves 10 opened on the lower side of the second inner ring 7. Then, six nuts 12 are respectively installed into the six nut grooves 10, and the threads of the first countersunk bolts 11 and nuts 12 are connected. The first inner ring 6 and the second inner ring 7 are connected to achieve axial fastening. Finally, the mounting ring 13 is installed into the mounting ring groove 3 of the outer ring 1. The four second countersunk bolts 15 are respectively inserted into the four annular array of second countersunk holes 14 opened on the upper side of the mounting ring 13, so that the threaded part of the second countersunk bolt 15 extends into the interior of the outer ring 1, completing the fixation of the mounting ring 13 and the outer ring 1, thereby realizing the overall assembly of the inner ring assembly and the outer ring 1. When disassembling, the second countersunk bolts 15 and the first countersunk bolts 11 are unscrewed in reverse order, so that the first inner ring 6, the second inner ring 7 and the mounting ring 13 can be quickly separated from the outer ring 1, greatly improving the disassembly and assembly efficiency. The sealing mechanism uses multiple structural elements to prevent external dust and other debris from entering the support. Two symmetrically arranged connecting ring grooves 18 are respectively opened on the outer surfaces of the first inner ring 6 and the second inner ring 7. The four connecting rings 19 are divided into two groups, with two rings in each group spliced ​​together to form a complete ring, which is then installed in the two connecting ring grooves 18 to provide a mounting carrier for the fixing rings 20. The four fixing rings 20 are respectively fixedly connected to the sides of the four connecting rings 19 that are far apart from each other, and are correspondingly set in the gaps between the outer ring 1 and the first inner ring 6 and the second inner ring 7. The four sealing rings 21 are respectively fixedly connected to the outer surfaces of the four fixing rings 20. Two of the sealing rings 21 extend into the first sealing ring groove 16 opened on the upper side of the mounting ring 13, and the other two sealing rings 21 extend into the second sealing ring groove 17 opened on the lower side of the outer ring 1. This forms a multi-layer sealing structure consisting of connecting rings 19, fixing rings 20, sealing rings 21, first sealing ring groove 16, and second sealing ring groove 17, which effectively prevents external debris from entering the support, avoids wear on the rollers 5 and raceways due to debris intrusion, and ensures long-term stable operation of the support. The synergistic multi-stage gradient heat treatment process includes the following steps: With stepped temperature control, segmented cooling and gradient tempering as the core, the slewing bearing substrate is first slowly preheated to 400-600℃ to eliminate initial stress, and then gradually heated to 850-950℃ through 2-4 temperature gradients to complete austenitization, avoiding microstructural defects caused by sudden temperature changes. The quenching stage employs a graded cooling strategy of first water cooling, then oil cooling, and finally air cooling, which forms a high-hardness hardened layer on the support surface with a Rockwell hardness value of 58-62 HRC, while retaining the tough core structure with a Rockwell hardness value of 38-45 HRC. Finally, the slewing bearing undergoes multi-stage gradient tempering at 180℃, 250℃, and 350℃ to eliminate residual quenching stress and promote the formation of a composite microstructure of ultrafine grains, bainite, and retained austenite. Combined with the composition optimization design of Ti and Nb microalloying in the substrate and rare earth element purification of grain boundaries, the bearing achieves a balance between surface hardness and internal toughness, significantly improving impact toughness and fatigue life. Structural Description: Outer Ring 1: The outer ring 1 is the integral load-bearing base component of the slewing bearing. The outer ring 1 provides a fixed mounting surface for the outer gear ring 2. The outer surface of the outer ring 1 is used to fit and fix the outer gear ring 2. The upper side of the outer ring 1 is provided with a mounting ring groove 3, which provides a carrier for the mounting ring groove 3. The inner side of the outer ring 1 is used to install the first inner ring 6 and the second inner ring 7. The outer ring 1, the first inner ring 6, and the second inner ring 7 cooperate to form a load-bearing space. The outer ring 1 has undergone coordinated multi-stage gradient heat treatment and composition optimization, and has high toughness characteristics. The outer ring 1 can stably withstand axial force, radial force, and overturning moment. External gear ring 2: External gear ring 2 is a power transmission component. External gear ring 2 is fixedly sleeved on the outer surface of outer ring 1. External gear ring 2 transmits power to drive the slewing bearing as a whole to achieve slewing motion by meshing with an external drive structure. Mounting groove 3: Mounting groove 3 is the mounting reference structure. Mounting groove 3 is opened on the upper side of outer ring 1. Mounting groove 3 provides precise mounting space and positioning reference for mounting ring 13. The bottom wall of mounting groove 3 is used to open roller groove 4. Mounting groove 3 provides a carrier for opening roller groove 4. Roller groove 4: The roller groove 4 is the mounting and rolling channel structure of the roller 5. There are eight roller grooves 4 in total. The eight roller grooves 4 are arranged in a ring array on the bottom wall of the mounting ring groove 3. The eight roller grooves 4 are used to install eight rollers 5 respectively. The roller grooves 4 cooperate with the roller ring grooves 8 of the first inner ring 6 and the second inner ring 7. The roller grooves 4 and the roller ring grooves 8 together form the rolling channel of the roller 5. Roller 5: Roller 5 is a friction conversion and load-bearing component. There are eight rollers 5 in total, which are installed in eight roller grooves 4 respectively. Part of the structure of the eight rollers 5 extends into the roller ring groove 8. When the outer ring 1 rotates relative to the first inner ring 6 and the second inner ring 7, the rollers 5 roll between the roller groove 4 and the roller ring groove 8. The rollers 5 convert the sliding friction between the outer ring 1 and the inner ring assembly into rolling friction. The rollers 5 reduce the resistance of the rotational motion. The rollers 5 directly bear the load between the outer ring 1 and the inner ring assembly. The rollers 5 assist the slewing bearing in stabilizing the force transmission. First inner ring 6: The first inner ring 6 is the core load-bearing component of the inner ring assembly. The first inner ring 6 has a ring structure. The first inner ring 6 and the second inner ring 7 are symmetrically installed on the inner side of the outer ring 1. The outer surface of the first inner ring 6 is provided with a roller ring groove 8. The first inner ring 6 provides a carrier for the roller ring groove 8. The first inner ring 6 is axially fastened to the second inner ring 7 by the first countersunk bolt 11. The first inner ring 6 and the second inner ring 7 together constitute the inner ring assembly. The first inner ring 6 has undergone coordinated multi-stage gradient heat treatment and composition optimization, and has high toughness characteristics. The first inner ring 6, together with the outer ring 1 and the second inner ring 7, can withstand multi-directional loads. Second inner ring 7: The second inner ring 7 is the core load-bearing component of the inner ring assembly. The second inner ring 7 has a ring structure and is symmetrically installed on the inner side of the outer ring 1 with the first inner ring 6. The outer surface of the second inner ring 7 has a roller ring groove 8, which provides a carrier for the roller ring groove 8. The lower side of the second inner ring 7 has a nut groove 10, which provides a carrier for the nut groove 10. The second inner ring 7 is axially fastened to the first inner ring 6 by the first countersunk bolt 11. The second inner ring 7 and the first inner ring 6 together constitute the inner ring assembly. The second inner ring 7 has undergone coordinated multi-stage gradient heat treatment and composition optimization, and has high toughness characteristics. The second inner ring 7, together with the outer ring 1 and the first inner ring 6, can withstand multi-directional loads. Roller annular groove 8: The roller annular groove 8 is the rolling channel structure of the roller 5. There are two roller annular grooves 8, which are respectively opened on the outer surface of the first inner ring 6 and the second inner ring 7. The two roller annular grooves 8 are connected along the axial direction. The roller annular groove 8 and the roller groove 4 of the outer ring 1 cooperate with each other. The roller annular groove 8 and the roller groove 4 together form the rolling channel of the roller 5. The roller annular groove 8 provides guidance and limit for the rolling of the roller 5. First countersunk hole 9: The first countersunk hole 9 is the installation channel structure for the first countersunk bolt 11. There are six first countersunk holes 9 in total. The six first countersunk holes 9 are arranged in a ring array on the upper side of the first inner ring 6. The first countersunk holes 9 are used to accommodate the head of the first countersunk bolt 11. The first countersunk holes 9 provide a passage for the first countersunk bolt 11 to pass through. The first countersunk holes 9 ensure the flatness of the first countersunk bolt 11 after installation. Nut groove 10: Nut groove 10 is the mounting and positioning structure of nut 12. There are six nut grooves in total. The six nut grooves 10 are arranged in a ring array on the lower side of the second inner ring 7. All six nut grooves 10 are hexagonal grooves. Nut grooves 10 are used to accommodate nut 12. Nut grooves 10 restrict the circumferential rotation of nut 12 through hexagonal structure. Nut grooves 10 provide positioning reference for the threaded connection between the first countersunk bolt 11 and nut 12. First countersunk bolt 11: The first countersunk bolt 11 is a fastening component of the inner ring assembly. There are six first countersunk bolts 11 in total. The six first countersunk bolts 11 are respectively installed in the six first countersunk holes 9. The threaded part of the first countersunk bolt 11 extends into the nut groove 10. The first countersunk bolt 11 is threadedly connected to the nut 12. The first countersunk bolt 11 achieves axial fastening between the first inner ring 6 and the second inner ring 7 through the thread force. The first countersunk bolt 11 ensures the structural integrity of the inner ring assembly. Nut 12: Nut 12 is a fastening component of the inner ring assembly. There are six nuts 12 in total. The six nuts 12 are installed in the six nut slots 10 respectively. The nuts 12 are threadedly connected to the first countersunk bolt 11. The nuts 12 work together with the first countersunk bolt 11 through the thread force to achieve axial fastening between the first inner ring 6 and the second inner ring 7. Nut 12 enhances the connection stability of the inner ring assembly. Mounting ring 13: Mounting ring 13 is an auxiliary fixing component between the inner ring assembly and the outer ring 1. Mounting ring 13 is installed inside the mounting ring groove 3 of the outer ring 1. A second countersunk hole 14 is provided on the upper side of mounting ring 13. Mounting ring 13 provides a carrier for opening the second countersunk hole 14. Mounting ring 13 is fixed to the outer ring 1 by a second countersunk bolt 15. Mounting ring 13 helps limit the axial position of the first inner ring 6. Mounting ring 13 ensures the assembly stability of the inner ring assembly and the outer ring 1. Second countersunk hole 14: The second countersunk hole 14 is the installation channel structure for the second countersunk bolt 15. There are four second countersunk holes 14 in total. The four second countersunk holes 14 are arranged in a ring array on the upper side of the mounting ring 13. The second countersunk holes 14 are used to accommodate the head of the second countersunk bolt 15. The second countersunk holes 14 provide a passage for the second countersunk bolt 15 to pass through. The second countersunk holes 14 ensure the flatness of the second countersunk bolt 15 after installation. Second countersunk bolt 15: The second countersunk bolt 15 is a fastening component between the mounting ring 13 and the outer ring 1. There are four second countersunk bolts 15 in total. The four second countersunk bolts 15 are respectively installed in the four second countersunk holes 14. The threaded part of the second countersunk bolt 15 extends into the interior of the outer ring 1. The second countersunk bolt 15 achieves the fixation of the mounting ring 13 and the outer ring 1 through threaded connection. The second countersunk bolt 15 indirectly ensures the assembly stability of the inner ring assembly and the outer ring 1. First sealing ring groove 16: The first sealing ring groove 16 is the mounting and sealing structure of the sealing ring 21. The first sealing ring groove 16 is opened on the upper side of the mounting ring 13. The first sealing ring groove 16 is used to accommodate two sealing rings 21. The first sealing ring groove 16 and the sealing ring 21 cooperate to form a sealing surface. The first sealing ring groove 16 prevents external debris from entering the interior from the upper side of the slewing bearing. Second sealing ring groove 17: The second sealing ring groove 17 is the installation and sealing structure of the sealing ring 21. The second sealing ring groove 17 is opened on the lower side of the outer ring 1. The second sealing ring groove 17 is used to accommodate two sealing rings 21. The second sealing ring groove 17 and the sealing ring 21 cooperate to form a sealing surface. The second sealing ring groove 17 prevents external debris from entering the interior from the lower side of the slewing bearing. Connecting ring groove 18: The connecting ring groove 18 is the mounting and positioning structure of the connecting ring 19. There are two connecting ring grooves 18, which are respectively opened on the outer surface of the first inner ring 6 and the second inner ring 7. The two connecting ring grooves 18 are arranged symmetrically from top to bottom. The connecting ring grooves 18 are used to install the connecting ring 19, provide a positioning reference for the connecting ring 19, and restrict the axial displacement of the connecting ring 19. Connecting ring 19: The connecting ring 19 is the mounting base component of the fixed ring 20. There are four connecting rings 19 in total. The four connecting rings 19 are installed in the two connecting ring grooves 18 respectively. The two connecting rings 19 in each connecting ring groove 18 are combined to form a complete ring. The connecting ring 19 is fixedly connected to the fixed ring 20. The connecting ring 19 provides a mounting carrier for the fixed ring 20. The connecting ring 19 connects the fixed ring 20 with the first inner ring 6 and the second inner ring 7 as a whole. Fixing ring 20: The fixing ring 20 is the mounting and support component of the sealing ring 21. There are four fixing rings 20 in total. The four fixing rings 20 are respectively fixedly connected to the four connecting rings 19 on the opposite sides. The fixing rings 20 are set in the gap between the outer ring 1 and the first inner ring 6 and the second inner ring 7. The fixing rings 20 fill part of the gap space. The fixing rings 20 are fixedly connected to the sealing ring 21. The fixing rings 20 provide installation support for the sealing ring 21 and ensure the installation stability of the sealing ring 21. Sealing ring 21: Sealing ring 21 is the core sealing component of the slewing bearing. There are four sealing rings 21 in total. The four sealing rings 21 are fixedly connected to the outer surface of the four fixed rings 20 respectively. The four sealing rings 21 extend into the interior of the first sealing ring groove 16 and the second sealing ring groove 17 respectively. The two sealing rings 21 in the first sealing ring groove 16 and the two sealing rings 21 in the second sealing ring groove 17 form two sets of seals, one above the other. The sealing rings 21 are tightly fitted with the first sealing ring groove 16 and the second sealing ring groove 17. The sealing rings 21 prevent external dust and other debris from entering the interior of the slewing bearing. The sealing rings 21 prevent the rollers 5 from wearing with the roller grooves 4 and roller ring grooves 8 due to the intrusion of debris. The sealing rings 21 ensure the long-term stable operation of the slewing bearing. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-toughness slewing bearing optimized in composition and synergized in multi-stage gradient heat treatment, comprising an outer ring (1), an outer gear ring (2) fixedly sleeved on the outer surface of the outer ring (1), an installation ring groove (3) formed on the upper side of the outer ring (1), eight roller grooves (4) formed on the bottom wall of the installation ring groove (3) and arranged in a ring array; eight rollers (5) installed in the eight roller grooves (4), a first inner ring (6) and a second inner ring (7) installed on the inner side of the outer ring (1) and arranged in an upper-lower symmetry; roller ring grooves (8) formed on the outer surfaces of the first inner ring (6) and the second inner ring (7) and in communication with each other; Eight rollers (5) extend towards a portion of the first inner ring (6) and the second inner ring (7) to the inside of the roller ring groove (8), characterized in that: a dismounting mechanism arranged on the outer ring (1), the first inner ring (6) and the second inner ring (7) and capable of quickly dismounting or mounting the first inner ring (6) and the second inner ring (7) from or on the inner part of the outer ring (1); the dismounting mechanism comprising six first countersunk holes (9), six nut grooves (10), six first countersunk bolts (11), six nuts (12), an installation ring (13), four second countersunk holes (14) and four second countersunk bolts (15); a sealing mechanism arranged on the outer ring (1), the first inner ring (6) and the second inner ring (7) and capable of blocking dust and other sundries from the outside, preventing the sundries from entering the inner part of the bearing; the sealing mechanism comprising a first sealing ring groove (16), a second sealing ring groove (17), two connecting ring grooves (18), four connecting rings (19), four fixing rings (20) and four sealing rings (21).

2. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 1, wherein: The six first countersunk holes (9) are all formed on the upper side of the first inner ring (6) and arranged in a ring array; the six nut grooves (10) are all formed on the lower side of the second inner ring (7) and arranged in a ring array; the six nut grooves (10) are all hexagonal grooves, and the six first countersunk bolts (11) are respectively installed in the six first countersunk holes (9).

3. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 2, wherein: The shank parts of the six first countersunk bolts (11) all extend into the six nut grooves (10), the six nuts (12) are respectively installed in the six nut grooves (10), and the six first countersunk bolts (11) are respectively in threaded connection with the six nuts (12).

4. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 1, wherein: The installation ring (13) is installed in the installation ring groove (3), the four second countersunk holes (14) are all formed on the upper side of the installation ring (13) and arranged in a ring array; the four second countersunk bolts (15) are respectively installed in the four second countersunk holes (14), and the shank parts of the four second countersunk bolts (15) are all in threaded extension into the inner part of the outer ring (1).

5. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 1, wherein: The first sealing ring groove (16) is formed on the upper side of the installation ring (13), and the second sealing ring groove (17) is formed on the lower side of the outer ring (1); the two connecting ring grooves (18) are respectively formed on the outer surfaces of the first inner ring (6) and the second inner ring (6) and arranged in an upper-lower symmetry.

6. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 1, wherein: The four connecting rings (19) are respectively installed inside the two connecting ring grooves (18), and two connecting rings (19) are installed inside each connecting ring groove (18). The two connecting rings (19) inside each connecting ring groove (18) combine to form a complete ring, and the four fixing rings (20) are respectively fixedly connected to the four connecting rings (19) on the side away from each other.

7. The synergistically multi-stage gradient heat treated compositionally optimized high toughness slewing ring of claim 6, wherein: The four fixing rings (20) are respectively disposed in the gap between the outer ring (1) and the first inner ring (6) and the second inner ring (7), and the four sealing rings (21) are respectively fixedly connected to the outer surface of the four fixing rings (20); Four sealing rings (21) extend into the interior of the first sealing ring groove (16) and the second sealing ring groove (17), respectively. Two sealing rings (21) are installed inside the first sealing ring groove (16) and the second sealing ring groove (17).

8. A synergistic multi-stage gradient heat treatment process characterized by: The steps are as follows: S1: First, slowly preheat the slewing bearing substrate to 400-600℃ to eliminate initial stress, and then gradually increase the temperature to 850-950℃ through 2-4 temperature gradients to complete austenitization, avoiding microstructural defects caused by sudden temperature changes. S2: The quenching stage adopts a graded cooling strategy of first water cooling, then oil cooling, and finally air cooling to form a high-hardness hardened layer on the support surface with a Rockwell hardness value of 58-62 HRC, while retaining the tough core structure with a Rockwell hardness value of 38-45 HRC. S3: Finally, the slewing bearing undergoes multi-stage gradient tempering at 180℃, 250℃, and 350℃ to eliminate residual quenching stress, promote the formation of a composite microstructure of ultrafine grains, bainite, and retained austenite, and combine the composition optimization design of Ti and Nb microalloying in the substrate and rare earth element purification of grain boundaries to achieve a balance between surface hardness and internal toughness, significantly improving impact toughness and fatigue life.

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