Crossed roller bearing, bearing outer ring controllable fracture method and bearing outer ring assembly method

Abstract

The invention relates to the technical field of precision mechanical transmission, in particular to a crossed roller bearing and a controllable fracture method and an assembly method of a bearing outer ring. Comprising a bearing outer ring, a bearing inner ring and cylindrical rollers, the bearing outer ring is of a discontinuous closed circle structure, one or more fractures are formed in the bearing outer ring, and the bearing outer ring is formed by splicing multiple sections of outer rings; the outer ring is made of nodular cast iron or amorphous alloy, and one or more stress grooves are machined before controllable fracture; the invention further comprises an assembling method of the bearing and a controllable fracture method of the bearing outer ring. The bearing outer ring is designed to be of a discontinuous closed circle structure, controllable fracture is achieved, bearing assembly is facilitated, and the production efficiency and the product quality are effectively improved.

Description

Technical Field

[0001] The present application relates to the field of precision mechanical transmission technology, and in particular to a cross roller bearing and a controllable fracture method and assembly method of a bearing outer ring. Background Art

[0002] In the field of mechanical transmission, bearings are core components, and their performance and manufacturing process play a key role in the operation of the entire mechanical system. With the continuous development of industrial technology, the requirements for the precision, stability, and reliability of mechanical equipment are becoming increasingly higher. Performance indicators such as bearing rotation accuracy and rigidity have also become important factors in improving the overall performance of the equipment. As a bearing with a special structure, crossed roller bearings are widely used in various high-end fields such as precision machinery, robotics, aerospace, etc. due to their unique design that can achieve high load capacity and high-precision rotation within a limited space. Their performance improvement is of great significance to promoting the development of these industries.

[0003] In the past, for bearings with a crossed cylindrical roller structure, in order to improve the rotational accuracy and rigidity of the bearings, a design of thin-walled crossed roller bearings with inner and outer rings was usually adopted. Specifically, an assembly hole is opened in the middle of the outer diameter surface of the outer ring, and this assembly hole is used to install the roller. In order to ensure the stability of the assembly, an assembly plug is tightly fitted in the roller assembly hole. In order to position the assembly plug, a through hole is set in the horizontal direction of the assembly plug, and a positioning pin is inserted into the through hole. This method was a conventional means to solve the roller assembly and positioning problems of crossed roller bearings at the time, and to a certain extent met the needs of some application scenarios.

[0004] However, this existing technology has obvious defects. In order to ensure the high positioning accuracy of the assembly plug, the processing accuracy of the assembly plug needs to be greatly improved, which undoubtedly increases the equipment and manufacturing costs. At the same time, although the assembly plug is molded together with the raceway, when assembling the roller, the assembly plug must be removed first, and then the assembly plug must be put back in place after the roller is loaded. At this time, the axial error and radial error between the V-groove under the assembly plug and the V-raceway are difficult to accurately locate, causing the roller to run unevenly in the groove, affecting product performance and product life. In addition, because the assembly hole for assembling the roller is too small, and the two adjacent rollers in the cross-roller bearing must be arranged in a cross shape, automated assembly cannot be achieved, and manual loading must be used, resulting in low assembly efficiency and high cost. Summary of the Invention

[0005] The first purpose of this application is to provide a cross roller bearing.

[0006] The above technical purpose of the present application is achieved by the following technical solution: a cross-roller bearing, comprising a bearing outer ring, a bearing inner ring and cylindrical rollers; the inner circumferential surface of the bearing outer ring and the outer circumferential surface of the bearing inner ring are both machined with a plurality of roller grooves adapted to the cylindrical rollers, the bearing inner ring is assembled in a concentric manner on the radially inner side of the bearing outer ring, and the cylindrical rollers are arranged in a cross shape in the roller grooves between the bearing inner ring and the bearing outer ring; the bearing outer ring is a non-continuous closed circle, and one or more fracture openings are arranged on the bearing outer ring.

[0007] By adopting the above technical solution, the bearing outer ring is designed as a non-continuous closed circle structure (segmented by one or more fracture openings) and a multi-segment structure is formed by controllable fracture, effectively solving the problem of automatic assembly caused by the small assembly hole of the existing whole outer ring cross-roller bearing, and further improving the assembly flexibility compared with the fixed two-flap structure - the number of fracture openings can be flexibly set according to the bearing size and load demand (such as one fracture opening forming a C-shaped opening structure, or multiple fracture openings forming a multi-segment splicing structure), adapting to more scenarios; with the aid of the adsorption positioning of the cylindrical rollers by the magnetic tool seat and the fixation of the spliced outer ring by the elastic auxiliary tool, efficient and accurate loading of the rollers and stable splicing of the outer ring are realized, greatly improving the assembly efficiency and reducing the labor cost; at the same time, by taking advantage of the characteristics of the fracture of the multi-segment outer ring after splicing being dense and the plastic deformation being negligible, the axial and radial errors generated during the traditional assembly of the plug are avoided, the size accuracy of the roller groove is ensured, the roller running resistance is reduced, and the rotation accuracy, structural rigidity and service life of the bearing are significantly improved; in addition, the bearing outer ring adopts material properties and stress groove design that adapt to controllable fracture, ensuring the controllability of the fracture process and the stability of the structure after splicing, providing reliable technical support for the large-scale application of cross-roller bearings in high-precision transmission scenarios. By machining a plurality of roller grooves on the inner circumferential surface of the bearing outer ring and the outer circumferential surface of the bearing inner ring, the number and distribution of the rollers can be flexibly designed according to the bearing load demand, the radial force, axial force and overturning moment are dispersed by the coordinated bearing of multiple grooves, and the overall bearing capacity and anti-deformation ability of the bearing are significantly improved; at the same time, the independent setting of the plurality of grooves can realize the orderly separation and accurate positioning of the cylindrical rollers, avoid friction and wear or motion interference between the rollers during high-speed operation, reduce the running noise and energy loss; in addition, the structural design of multiple grooves enables the bearing to maintain basic transmission performance through the normal work of other grooves when there is slight wear on the local rollers or grooves, prolonging the service life of the bearing, and providing a modular design basis for cross-roller bearings of different precision levels and different load demands, enhancing the adaptability and application flexibility of the product.

[0008] Optionally, the bearing outer ring is made of nodular cast iron or amorphous alloy.

[0009] By adopting the technical scheme, when the bearing outer ring is made of nodular cast iron material, the advantages of high hardness and brittle fracture characteristics after heat treatment are fully utilized: the structural strength and wear resistance required by the bearing outer ring roller channel are ensured to meet the requirements of precise transmission scenarios on carrying capacity; and the outer ring can be accurately fractured along the stress groove in the controllable fracture process, the plastic deformation at the fracture is extremely small, the initial size can be restored after splicing, and the fracture is tightly matched without gaps, which effectively maintains the size accuracy of the roller channel. At the same time, the nodular cast iron material has wide sources and low processing cost, which is beneficial to reduce the bearing manufacturing cost, and the mature and stable heat treatment process (such as quenching and tempering) can optimize the material uniformity, provide a reliable foundation for subsequent processes, and improve the production stability and economy. When the amorphous alloy is selected, the unique structure of the atom disordered arrangement has the characteristics of high strength, high hardness and low plasticity, the plastic deformation is highly controllable during fracture, the fracture is neat and the gap is extremely small after fracture along the preset stress groove; the characteristics of no grain boundary also give the roller channel better surface integrity, which can reduce the friction loss of the channel, and is suitable for high-frequency, high-speed and high-precision transmission scenarios; and the amorphous alloy forming process is flexible, combined with injection / molding and graphene assisted technology, the forming accuracy of the outer ring split structure can be accurately controlled, the subsequent grinding processing allowance is reduced, the production efficiency and product performance consistency are further improved, and the application potential of the bearing in high-end equipment field is expanded. The two materials adapt to different application scenarios and cost requirements, providing multiple reliable choices for bearing design and manufacturing.

[0010] Optionally, the bearing outer ring is a continuous closed circle before controllable fracture, and one or more stress grooves are machined on the outer circumferential surface and / or two axial end surfaces in the circumferential direction; the one or more fracture openings are formed by controllable fracture along the stress groove, and the bearing outer ring is a non-continuous closed circle after fracture.

[0011] By adopting the technical scheme, stress grooves are machined at one or more preset positions on the outer circumferential surface and / or axial end surface before controllable fracture of the bearing outer ring, which can accurately guide the fracture position, make the bearing outer ring realize controllable fracture along the preset path, avoid irregular cracks or excessive plastic deformation during the fracture process, ensure that the fracture shapes of each section of the outer ring after fracture are regular and have high matching degree; at the same time, the setting of the stress groove reduces the tension required for fracture, reduces the load requirement of the expansion fracture tool, improves the stability and controllability of the fracture process, and cooperates with the brittle fracture characteristics of the material to make the fracture almost without plastic deformation, so that the initial size accuracy can be restored after splicing, which guarantees the continuity and consistency of the roller channel, lays a foundation for the smooth operation of the roller during subsequent assembly, and at the same time, the standardized fracture path also facilitates the process uniformity in batch production, improves the efficiency and reliability of the processing of the non-continuous closed circle structure outer ring.

[0012] The second object of the present application is to provide a controllable fracture method of a bearing outer ring.

[0013] The above technical objectives of the present application are achieved through the following technical solutions: A method for controllable fracture of a bearing outer ring, comprising the following steps: S201: Locating the stress groove on the bearing outer ring, wherein the stress groove is located at one or more positions along the circumferential direction on the outer cylindrical surface and / or two axial end surfaces of the bearing outer ring, and concentrically sleeve the bearing outer ring on the expansion and breaking fixture seat; S202: applying tension from the inner side of the bearing outer ring at the position corresponding to the stress groove through the expansion and breaking fixture, so that the bearing outer ring can be controllably fractured along the stress groove to form one or more fracture openings, forming a discontinuous closed circle.

[0014] By adopting the above technical solution, a stress groove is preset on the outer ring of the bearing and a directional tension is applied in combination with an expansion and breaking fixture, thereby achieving precise and controllable fracture of the outer ring of the bearing along the stress groove. The stress concentration effect is used to ensure the stability of the fracture path, avoiding irregular cracks or excessive plastic deformation that may occur when there is no preset groove. The fracture surfaces of each section of the outer ring formed after the fracture have a high degree of fit and minimal loss of dimensional accuracy, and the initial structural integrity can be restored after splicing. At the same time, the flexible design of one or more stress grooves ensures the rationality of the discontinuous closed circle structure after fracture, laying the foundation for precise splicing during subsequent assembly. The concentric positioning of the expansion and breaking fixture further ensures the stability and consistency of the fracture process. This method is simple to operate and has strong controllability. It not only reduces the excessive dependence on equipment accuracy, but also achieves uniformity of the fracture quality of the bearing outer ring in mass production, providing key process support for the large-scale manufacturing of discontinuous closed circle structure outer ring cross roller bearings.

[0015] Optionally, the method further includes: S301: When using the brittle fracture process, a directional tension is applied along the preset stress groove position to the bearing outer ring made of zirconium-based or gallium-based amorphous alloy. The brittle fracture characteristics of the material are utilized to cause the bearing outer ring to undergo brittle fracture along the stress groove, forming a rough, irregular and unique fracture surface. S302: After breaking, the integrity of the fracture is checked to prevent defects and ensure the uniqueness of the joint surface of each outer ring segment and the integrity of the entire ring after splicing; S303: When using injection molding or die casting, a single or multi-layer graphene sheet is placed at one or more locations along the circumference of the mold cavity, and the cavity is divided into multiple segments. After injecting the zirconium-based or gallium-based amorphous alloy material, the material is separated along the graphene sheet by a brittle fracture effect, utilizing the high-temperature resistance and ultra-thinness of graphene, forming nano-scale gaps between the segments. S304: After the material is pressure-formed, it is taken out and the segments are spliced ​​into a whole circle, which is then ground for assembly. Alternatively, a graphene sheet is placed in the mold to form a single-opening structure. During assembly, external force is applied along the opening to open it, and the external force is released to reset it after the roller is installed.

[0016] By adopting the above-mentioned technical solutions, a brittle fracture process and graphene-assisted forming process designed for the outer rings of zirconium- or gallium-based amorphous alloy bearings leverage the inherent brittle fracture properties of the material and the nanoscale separation effect of graphene to achieve precise segmentation (forming one or more fractures) of the bearing outer ring. This ensures a high degree of conformity at the fracture or separation surface. The brittle fracture process uses directional tension to achieve low fracture roughness and minimal flatness error, while the graphene-assisted forming process utilizes nanoscale gaps to achieve a nearly seamless splicing. The complementary nature of the two processes allows for adaptability to different production scenarios. Furthermore, the single-opening structure design, combined with the elastic properties of the material, simplifies the roller assembly process and avoids damage to the bearing structural integrity caused by traditional assembly holes. Subsequent inspection and grinding further ensure the dimensional accuracy of the spliced ​​outer ring and the continuity of the roller groove, effectively improving the rotational accuracy and service life of the bearing. Both processes are easily automated, significantly enhancing production efficiency and product quality stability, providing reliable technical support for the large-scale manufacturing of bearing outer rings with discontinuous closed-circle structures.

[0017] The third purpose of this application is to provide an assembly method for a cross roller bearing.

[0018] The above technical objectives of the present application are achieved through the following technical solutions: A method for assembling a cross roller bearing, comprising the following steps: S101: Concentrically sleeve the inner ring of the bearing on a magnetic fixture seat; S102: Use manual or automated equipment to place cylindrical rollers in a cross pattern in the roller grooves outside the bearing inner ring. Use the magnetic fixture to attract the cylindrical rollers to prevent them from falling. S103: Each segment of the bearing outer ring of the discontinuous closed circle structure is spliced ​​and combined according to the unique corresponding splicing marks, and is sleeved on the outer circle side of the bearing inner ring and the cylindrical roller; S104: Use an elastic auxiliary tool to cover the outer side of the bearing outer ring after splicing to maintain the splicing state of the bearing outer ring; S105: The assembled bearing outer ring, bearing inner ring and cylindrical roller are placed in a demagnetization device for demagnetization.

[0019] By adopting the technical scheme, the precise positioning of the bearing inner ring by the magnetic tool seat and the adsorption and fixation of the cylindrical rollers are utilized, the problem of difficult roller filling caused by the narrow assembly hole of the traditional integral outer ring bearing is solved, the artificial or automatic equipment can efficiently complete the cross arrangement of the cylindrical rollers, and the assembly efficiency is greatly improved; through the unique corresponding splicing mark and the elastic auxiliary tool, the precise splicing and stable fixation of the non-continuous closed circular structure outer ring are ensured, the channel deviation caused by splicing misplacement is avoided, and the smoothness of the roller operation is ensured; the demagnetization treatment eliminates the residual magnetic field of the magnetic tool seat, prevents the adsorption of iron filings and other impurities from affecting the service life of the bearing, and at the same time, the whole process is realized from the inner ring positioning, the roller filling to the outer ring splicing, which is controllable, simplifies the assembly operation, improves the assembly precision, and provides a reliable technical path for the large-scale and automatic production of the cross roller bearing.

[0020] In summary, the present application at least contains the following one beneficial effect: 1. The bearing outer ring is designed as a non-continuous closed circular structure (segmented by one or more fracture openings) and forms a multi-segment structure through controllable fracture, effectively solving the problem of automatic assembly caused by the small assembly hole of the existing whole outer ring cross roller bearing, and further improving the assembly flexibility compared to the fixed two-petal structure - the number of fracture openings can be flexibly set according to the bearing size and load demand (such as one fracture opening forming a C-shaped opening structure, or multiple fracture openings forming a multi-segment splicing structure), which is suitable for more scenarios; With the help of magnetic tool holder for adsorbing and positioning cylindrical rollers and elastic auxiliary tool for fixing spliced outer ring, efficient and accurate roller filling and stable splicing of outer ring are realized, which greatly improves the assembly efficiency and reduces the labor cost; At the same time, by utilizing the characteristics of tight fracture and negligible plastic deformation after splicing of multi-segment outer ring, the axial and radial errors generated during the traditional assembly of the plug are avoided, the size accuracy of the roller groove is ensured, the roller running resistance is reduced, and the rotation accuracy, structural rigidity and service life of the bearing are significantly improved; In addition, the bearing outer ring adopts material characteristics and stress groove design suitable for controllable fracture, ensuring the controllability of the fracture process and the stability of the spliced structure, providing reliable technical support for the large-scale application of cross roller bearings in high-precision transmission scenarios. By machining several roller grooves on the inner circumferential surface of the bearing outer ring and the outer circumferential surface of the bearing inner ring, the number and distribution of rollers can be flexibly designed according to the bearing load demand, and the radial force, axial force and overturning moment can be dispersed through the coordinated bearing of multiple grooves, significantly improving the overall bearing capacity and anti-deformation ability of the bearing; At the same time, the independent setting of several grooves can realize the orderly separation and accurate positioning of cylindrical rollers, avoid friction and wear or motion interference between rollers during high-speed operation, reduce operating noise and energy loss; In addition, the structure design of multiple grooves enables the bearing to maintain basic transmission performance through the normal work of other grooves when there is slight wear on local rollers or grooves, prolonging the service life of the bearing, and providing a modular design basis for cross roller bearings of different precision levels and different load demands, enhancing the adaptability and application flexibility of the product.

[0021] 2. The use of magnetic fixtures to accurately position the inner ring of the bearing and adsorb and fix the cylindrical rollers solves the problem of difficulty in roller loading in traditional integral outer ring bearings due to the narrow assembly hole, enabling manual or automated equipment to efficiently complete the cross-arrangement of cylindrical rollers, greatly improving assembly efficiency; through unique corresponding splicing marks and elastic auxiliary tools, the precise splicing and stable fixation of the outer ring of the non-continuous closed circle structure are ensured, avoiding channel deviation caused by splicing misalignment and ensuring the smooth operation of the rollers; demagnetization treatment eliminates the residual magnetic field of the magnetic fixture to prevent the adsorption of impurities such as iron filings that affect the bearing life. At the same time, the overall process realizes full process control from inner ring positioning, roller loading to outer ring splicing, which not only simplifies assembly operations but also improves assembly accuracy, providing a reliable technical path for the large-scale and automated production of crossed roller bearings.

[0022] 3. One or more stress grooves are preset on the outer ring of the bearing and directional tension is applied in combination with the expansion and breaking fixture, so that the outer ring of the bearing can be precisely and controllably fractured along the stress groove. The stress concentration effect is used to ensure the stability of the fracture path, avoiding irregular cracks or excessive plastic deformation that may occur when there is no preset groove. The fracture surfaces of each section of the outer ring formed after the fracture have a high degree of fit and minimal loss of dimensional accuracy, and the initial structural integrity can be restored after splicing. At the same time, the flexible distribution of the stress grooves ensures the symmetry and rationality of the discontinuous closed circle structure after fracture, laying the foundation for precise splicing during subsequent assembly. The concentric positioning of the expansion and breaking fixture further ensures the stability and consistency of the fracture process. This method is easy to operate and has strong controllability. It not only reduces the excessive dependence on equipment accuracy, but also achieves uniform fracture quality of the bearing outer ring in mass production, providing key process support for the large-scale manufacturing of discontinuous closed circle structure outer ring cross roller bearings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural diagram of a crossed roller bearing; Figure 2 It is a schematic diagram of the assembly of a crossed roller bearing; Figure 3 It is a flow chart of the steps of a method for assembling a crossed roller bearing; Figure 4 It is a schematic diagram of controlled fracture of the outer ring of a bearing; Figure 5 The present invention is a flowchart of the steps of a method for controlled fracture of a bearing outer ring.

[0024] Reference numerals 1. Bearing outer ring; 2. Bearing inner ring; 3. Cylindrical roller; 4. Roller groove; 5. Stress groove; 6. Magnetic fixture seat; 7. Expansion fixture seat. DETAILED DESCRIPTION

[0025] The present application is further described in detail below with reference to the accompanying drawings.

[0026] Example 1 In this embodiment, referring to Figures 1-5 , a crossed roller bearing, comprising an outer ring 1, an inner ring 2, cylindrical rollers 3 and a sealing ring, wherein the inner circumferential surface of the outer ring 1 and the outer circumferential surface of the inner ring 2 are both processed with a plurality of roller grooves 4 adapted to the cylindrical rollers 3. The roller grooves 4 can be designed as a single row or multiple row structure according to the rigidity requirements of the bearing. When used in a light load and high precision scenario, a single row of roller grooves 4 can be set, and the single row of cylindrical rollers 3 adapted to be arranged in a cross pattern; when used in a heavy load and high rigidity scenario, multiple rows (2 rows or more) of roller grooves 4 are preferably set; the inner ring 2 of the bearing is assembled on the radial inner side of the outer ring 1 of the bearing in a concentric manner, and the cylindrical rollers 3 are arranged in a cross pattern in the roller grooves 4 between the inner ring 2 and the outer ring 1 of the bearing, and the sealing ring is arranged at the axial end between the outer ring 1 and the inner ring 2 of the bearing. Such a structural design enables the bearing to operate stably and realizes high-precision rotation and load-bearing functions. This is because the cross-arrangement of the rollers in the groove can effectively disperse the load and improve the rigidity and rotation accuracy of the bearing, while the sealing ring can prevent dust and debris from entering the bearing and ensure the service life of the bearing.

[0027] Specifically, the bearing outer ring 1 is a discontinuous closed circular structure with one or more fractures, constructed from multiple joined outer ring segments. The bearing outer ring 1 is made of ductile iron or an amorphous alloy. Ductile iron, after heat treatment, exhibits high hardness and brittle fracture properties, making it suitable for manufacturing bearing outer rings that require fracture and subsequent assembly. The special properties of ductile iron minimize plastic deformation during fracture, ensuring that the fractured section returns to its original dimensions after assembly, thus guaranteeing the dimensional accuracy of the outer ring raceway. In addition to ductile iron, metals with a tensile strength ≥800 MPa and an elongation of no more than 3% (such as zirconium-based alloys and gallium-based alloys), ceramics, or composite materials can also be used. Amorphous alloys, due to their unique structure of disordered atoms, also exhibit controllable plastic deformation during fracture, making them suitable for processing this discontinuous closed circular structure. This broadens the material selection and meets the diverse performance requirements of bearing outer rings under different operating conditions.

[0028] Before the controllable fracture of the bearing outer ring 1, stress grooves 5 are machined on the outer circumferential surface and / or the two axial end surfaces at one or more positions in the circumferential direction. Each section of the outer ring is formed by controllable fracture along the stress grooves 5. There are various ways to machine the stress grooves 5, such as wire cutting, laser cutting, etc. Wire cutting is a high-precision machining method that can ensure the size and shape accuracy of the stress grooves 5; laser cutting has the advantage of fast processing speed. By machining stress grooves 5 at these positions, the bearing outer ring 1 can accurately fracture into multiple sections along the positions of the stress grooves 5 when subjected to tension. In addition, another stress groove machining and assembly method can also be used, that is, only one stress groove 5 is machined at a point in the circumferential direction before the controllable fracture of the bearing outer ring 1. After machining, the outer ring is subjected to an expansion fracture operation, and after expansion fracture, the overall outer ring forms a C-shaped structure. Subsequently, an external force is applied along the single opening to expand it, and the opening is opened to a size that can accommodate the rollers by utilizing the elastic deformation capability of the outer ring material, and then the rollers are assembled. After assembly, the outer ring can stably constrain the rollers by its own elastic recovery characteristics. This method has advantages in some scenarios with specific requirements for assembly convenience, and through actual assembly testing, the bearings assembled in this way meet the design requirements in terms of roller smoothness and overall stability under subsequent simulated working conditions.

[0029] Each section of the bearing outer ring 1 formed by fracture is provided with a unique splicing mark for precise splicing of each section. These marks can be notches, numbers, letters, etc., which can ensure accurate correspondence of each section of the outer ring when splicing. For example, "A1" can be engraved on one section of the outer ring, and "A2" on the corresponding section. When splicing, align "A1" and "A2" to achieve precise splicing.

[0030] The surface of the roller groove 4 of the bearing outer ring 1 is subjected to high-frequency quenching treatment or surface coating treatment. High-frequency quenching treatment can improve the hardness and wear resistance of the surface of the roller groove 4, and surface coating treatment can further improve the performance of the groove surface, such as reducing the friction coefficient. For example, the surface coating can use titanium nitride coating, which has good hardness and wear resistance, and can effectively improve the service life of the bearing.

[0031] Specifically, the bearing inner ring 2 is concentrically arranged on the inner side of the bearing outer ring 1, and the outer circumferential surface is machined with roller grooves 4 adapted to the cylindrical rollers 3. The bearing inner ring 2 can be made of conventional bearing steel material, which has high strength and toughness to meet the use requirements of the bearing. The machining process of the bearing inner ring 2 can use conventional processes such as forging, turning, and grinding to ensure its size accuracy and surface quality.

[0032] Cylindrical rollers 3 are arranged in a cross shape in roller grooves 4 between bearing inner ring 2 and bearing outer ring 1. The material of cylindrical rollers 3 is usually bearing steel, and the surface thereof is precisely processed, having high dimensional accuracy and surface finish. The size and shape of cylindrical rollers 3 need to be adapted to roller grooves 4 to ensure smooth rolling in the grooves.

[0033] Sealing rings are arranged at the axial ends between bearing outer ring 1 and bearing inner ring 2. The sealing rings can be made of elastic materials such as rubber and silica gel, and are usually annular in shape. The sealing rings prevent dust, debris and the like from entering the bearing interior, and also prevent lubricating oil from leaking, ensuring normal operation of the bearing.

[0034] The implementation principle of the present embodiment is that the cross roller bearing of the present embodiment adopts the design of a bearing outer ring 1 of a non-continuous closed circle structure and a whole bearing inner ring 2, utilizes the special properties of nodular cast iron, forms one or more fracture openings in the bearing outer ring 1 by processing stress grooves 5 and controllable fracture, and solves the problems of difficult assembly plug positioning accuracy and low roller assembly efficiency in the prior art. The arrangement of the splicing marks ensures the accuracy of the outer ring splicing, the high-frequency quenching or surface coating treatment improves the performance of the roller grooves 4, and the addition of the sealing rings enhances the protection performance of the bearing. These improvements make the assembly of the bearing more convenient, enable automatic mass production, improve the production efficiency and reduce the production cost, while ensuring the accuracy and service life of the bearing, and have made significant progress compared with the prior art.

[0035] Embodiment 2 With reference to Figures 2-3 The assembly method of the cross roller bearing provided by the present embodiment includes the following steps: S101: concentrically set bearing inner ring 2 on magnetic tool seat 6 with magnetism. Magnetic tool seat 6 can adopt an electromagnetic chuck or a permanent magnet to realize the magnetic adsorption function. In operation, bearing inner ring 2 is carefully placed on magnetic tool seat 6 to ensure its concentricity, and bearing inner ring 2 is fixed by the magnetism of magnetic tool seat 6 to prevent it from moving in subsequent operations.

[0036] S102: arrange cylindrical rollers 3 in a cross shape in roller grooves 4 outside bearing inner ring 2 in sequence by manual or automatic equipment, and adsorb cylindrical rollers 3 by the magnetism of magnetic tool seat 6 to prevent cylindrical rollers 3 from falling. If manual placement is adopted, the operator needs to place cylindrical rollers 3 into roller grooves 4 one by one according to the cross-shaped arrangement. If automatic equipment is adopted, a mechanical hand or the like can be used to accurately place cylindrical rollers 3 at the specified position by programming the action of the mechanical hand. Due to the magnetism of magnetic tool seat 6, cylindrical rollers 3 are adsorbed in roller grooves 4 and will not fall.

[0037] S103: The segments of the bearing outer ring 1 with a non-continuous closed circular structure are spliced ​​and combined according to the unique corresponding splicing marks, and then mounted on the outer circumference of the bearing inner ring 2 and cylindrical roller 3. During the splicing, the operator needs to carefully observe the splicing marks, accurately align the segments of the outer ring, and then slowly mount them on the outer circumference of the bearing inner ring 2 and cylindrical roller 3.

[0038] S104: Use an elastic auxiliary tool to cover the outside of the assembled bearing outer ring 1 to maintain the assembled bearing outer ring 1. The auxiliary tool can be a rubber band, a plastic ring, etc. The auxiliary tool is placed on the outside of the assembled bearing outer ring 1, and its elastic contraction force is used to tightly connect the outer ring segments together to prevent them from falling apart.

[0039] S105: Place the assembled bearing outer ring 1, bearing inner ring 2, and cylindrical roller 3 in a demagnetization device for demagnetization. The demagnetization device can be a common AC demagnetizer. Place the assembled bearing in the demagnetization device and perform demagnetization according to the device's operating instructions to remove the magnetism from the bearing and ensure normal operation of the bearing.

[0040] The working principle of this embodiment is as follows: The assembly method utilizes a magnetic fixture 6 to secure the bearing inner ring 2 and attract the cylindrical roller 3, making placement of the cylindrical roller 3 more convenient and stable, and preventing the roller from falling during manual operation. The outer rings of the non-continuous closed circular structure are spliced ​​according to markings and maintained in the spliced ​​state using elastic auxiliary tools, ensuring the accuracy and stability of the outer ring splicing. Finally, demagnetization is performed to remove the magnetism from the bearing and prevent its impact on bearing performance. The entire assembly process is simple to operate, enabling automated mass production and improving production efficiency, significantly improving over the existing manual assembly methods.

[0041] Example 3 Reference Figures 4-5 The controllable fracture method of the bearing outer ring provided in the embodiment of the present application includes the following steps: S201: Locate the stress groove 5 on the outer ring 1 of the thin-walled cross bearing. The stress groove 5 is located at one or more locations along the circumferential direction on the outer cylindrical surface and / or two axial end surfaces of the bearing outer ring 1. The bearing outer ring 1 is concentrically mounted on the expansion fixture 7. When locating the stress groove 5, precise measurements can be made using tools such as measuring tools to ensure the accurate positioning of the stress groove 5. The design of the expansion fixture 7 must ensure that the bearing outer ring 1 can be accurately fixed in the center position and that tension can be applied to the stress groove 5 from the inside.

[0042] S202: Apply tension to the bearing outer ring 1 from the inside of the stress groove 5 position through the expansion and breaking tool seat 7, so that the bearing outer ring 1 can be controlled to break along the stress groove 5 to form one or more broken openings, becoming a non-continuous closed circle. The expansion and breaking tool seat 7 can use hydraulic devices, mechanical transmission devices, etc. to apply tension. When applying tension, the tension needs to be slowly increased, so that the bearing outer ring 1 gradually breaks along the position of the stress groove 5, avoiding the situation that the breaking position is not accurate or over broken.

[0043] The implementation principle of the embodiment is: the controlled breaking method of the embodiment can accurately break the bearing outer ring 1 along the preset path to form one or more broken openings by precisely processing the stress groove 5 and applying tension using the expansion and breaking tool seat 7, and the plastic deformation at the broken position is minimal, ensuring the size accuracy after re-splicing. This method solves the problem of difficult control of breaking position and accuracy in the prior art, providing an effective solution for the manufacture of cross-roller bearings, making the production of bearings more efficient and accurate, and having obvious advantages over traditional machining methods.

[0044] Embodiment 4 In this embodiment, the cross-roller bearing further includes a retainer for separating and positioning the cylindrical rollers 3, and the structure of the retainer is adapted to the non-continuous closed circle design of the bearing outer ring 1, realizing complete annular or segmented assembly, and realizing the retainer assembly process that the traditional integral outer ring bearing cannot complete. Specifically, the retainer can be selected from the following three structure forms according to the bearing accuracy requirement and assembly scene: Integrated circular retainer: The whole is annular structure, a plurality of pockets matched with the cylindrical rollers 3 are uniformly arranged along the circumferential direction, and the pocket spacing is matched with the cross arrangement spacing of the roller channel 4. Since the bearing outer ring 1 is a non-continuous closed circle structure, the integrated circular retainer can be directly sleeved on the outer side of the roller after the cylindrical roller 3 is placed in the inner ring channel, without the need to install through the narrow assembly hole, solving the problem that the traditional integral outer ring cannot assemble the integrated circular retainer, ensuring that the roller does not move during high-speed operation, and significantly reducing the operating noise.

[0045] Integrated retainer with a cutout: a cutout is provided on the outer circumferential surface of the integrated circular retainer along the axial direction, and an elastic reset lap joint structure is arranged at the cutout. During assembly, the retainer can be sleeved on the outer side of the roller by opening the cutout, and the cutout is automatically closed by using the material elasticity, which is suitable for manual or semi-automatic assembly scene, and not only retains the stability of the integrated structure, but also simplifies the assembly operation.

[0046] Split type retainer: composed of several independent partition blocks, each partition block corresponds to the gap position of the adjacent two rollers. When assembling, the partition block needs to be embedded while the cylindrical roller 3 is put into the inner ring groove one by one. Although the installation difficulty of a single partition block is slightly higher than that of the integral retainer, with the help of the non-continuous closed circle design of the bearing outer ring 1, the position of the partition block can be adjusted through visual operation before splicing the outer ring, avoiding the misplacement of the retainer caused by limited assembly space under the traditional integral outer ring.

[0047] In this embodiment, the addition of the retainer further optimizes the motion trajectory of the cylindrical roller 3, reduces the direct friction between the rollers through the contact guidance of the pockets and the rollers, reduces the friction coefficient when the bearing is running, and prevents the rollers from tilting or deviating when bearing the overturning moment, thereby improving the rotation stability of the bearing. The three retainer structures are all based on the non-continuous closed circle characteristics of the bearing outer ring 1 to realize the assembly feasibility, providing flexible selection schemes for different application scenarios.

[0048] The implementation principle of this embodiment is: by designing three kinds of cross-roller retainer structures that are adapted to the non-continuous closed circle structure outer ring, the selection limitation of the retainer caused by the limited assembly space of the traditional integral outer ring bearing is broken. The integral circular retainer realizes the assembly of the complete annular structure with the help of the non-continuous characteristics of the outer ring, the notched retainer balances the structural stability and assembly convenience, and the split type retainer reduces the installation difficulty through visual operation before splicing the outer ring. The three schemes all improve the running accuracy and service life of the bearing through the precise matching of the retainer and the roller, further expanding the application scenarios of cross-roller bearings in the precision transmission field.

[0049] Embodiment 5 The method further comprises: S301: When adopting the brittle fracture process, a bearing outer ring 1 made of zirconium-based or gallium-based amorphous alloy is subjected to directional tension at the position of a preset stress groove 5, the brittle fracture characteristics of the material are utilized to make the bearing outer ring 1 brittle fracture along the stress groove 5, and a rough, irregular and unique fracture is formed; S302: After fracture, the integrity of the fracture is detected to prevent defects and ensure the uniqueness of the splicing surface of each section of the outer ring and the integrity of the complete ring after splicing; S303: When adopting the injection molding or die casting method, one or more single-layer or multi-layer graphene sheets are placed in the mold cavity in the circumferential direction, the cavity is divided into multiple sections, and after injecting the zirconium-based or gallium-based amorphous alloy material, the graphene is utilized for its high-temperature resistance and ultra-thin characteristics to form a separation similar to brittle fracture at the position of the graphene sheet, and a nanoscale gap is formed between each section. S304: After the material is pressure formed, it is taken out, spliced into a whole circle, and used for assembly after grinding processing; or a piece of graphene sheet is placed in the mold to form a single opening structure, and an external force is applied along the opening during assembly to make it open, and the roller is loaded and then the external force is released to reset.

[0050] In this embodiment, the non-continuous closed circle structure of the bearing outer ring 1 can be precisely segmented by two innovative processes, further improving the splicing accuracy and production efficiency. The first process is to add zirconium-based amorphous alloy or gallium-based amorphous alloy as an alternative material based on nodular cast iron, with a tensile strength ≥ 1500 MPa and an elongation ≤ 1%, combining high hardness and controllable brittle fracture characteristics. A V-shaped stress groove 5 with a depth of 0.3-0.5 mm and a width of 0.1-0.2 mm is processed on the outer surface of the bearing outer ring 1 using laser etching process. The etching track can be symmetrical or distributed as needed according to the required number of fracture openings, ensuring that the stress concentration coefficient reaches 3.5 or more. The hydraulic expansion fracture tool holder 7 is used, and the expansion fracture force loading rate is accurately controlled by PLC (0.5-1 kN / s), so that the material undergoes brittle fracture along the stress groove 5, with a fracture roughness Ra ≤ 1.6 μm and a plastic deformation layer thickness ≤ 50 μm. The segmented outer rings after fracture are detected by a three-coordinate measuring instrument, with a planeness error of the splicing surface ≤ 0.005 mm and an angle deviation ≤ 0.01°, achieving micron-level precision docking.

[0051] The second process is to select zirconium-based amorphous alloy or gallium-based amorphous alloy with a glass transition temperature Tg ≤ 400 ℃ and a crystallization temperature Tx ≥ 500 ℃, and to use single-layer or multi-layer graphene prepared by chemical vapor deposition, with a thickness of 0.34-3 nm and an area ≥ 100 mm², and a thermal stability ≥ 1000 ℃. One or more graphene sheets are installed at one or more positions along the circumference of the mold cavity of the bearing outer ring 1, or a graphene sheet is installed along the diameter direction, and the graphene sheet is fixed to the inner wall of the mold cavity by high-temperature resistant resin (such as polyimide). The amorphous alloy is heated to the undercooled liquid phase region (Tg + 50 ℃), and injected into the mold cavity at a pressure of 100-200 MPa. The graphene sheet separates the material into multiple segments or a ring structure with a single opening, and the gap width is equal to the thickness of the graphene sheet (nanometer level). After forming, cool to room temperature and demold, and precisely splice the segmented outer rings by vacuum suction tooling. The nanometer-level gap is seamlessly combined under intermolecular forces, and the roundness error of the spliced outer ring is ≤ 0.003 mm. The spliced outer ring is precisely ground to remove the graphene residual layer (thickness ≤ 3 nm), so that the surface roughness Ra of the roller groove 4 is ≤ 0.05 μm, and the size tolerance is controlled within ± 0.002 mm.

[0052] When a single-opening outer ring is formed from a single sheet of graphene, a specialized fixture applies radial force along the opening during assembly, expanding the gap to 1.2-1.5 times the roller diameter. After quickly inserting the cylindrical roller 3, the force is released, allowing the material to self-close due to its elastic recovery. The residual gap at the opening is ≤0.01mm, ensuring smooth roller operation. This process, which combines the nanometer-scale thickness of graphene with the superplastic forming capabilities of amorphous alloys, surpasses the precision limits of traditional mechanical split-half processes, achieving submicron-level splicing accuracy. Furthermore, the single-opening design provides a new approach to roller assembly, avoiding the damage to the bearing's structural integrity caused by traditional assembly holes. This process is suitable for applications such as robotic joints and optical instruments, where bearing precision and stability are extremely demanding. While maintaining bearing rotational accuracy (≤0.001mm), it also improves production efficiency by 30%-50%.

[0053] The implementation principle of this embodiment is: through the superplastic forming properties of amorphous alloys, near-net-net forming is achieved in the supercooled liquid phase, while the atomic-level thickness of graphene is used as a physical separation layer to achieve material separation with nanometer-level precision. This method avoids the stress concentration and thermal deformation problems encountered in traditional mechanical processing, allowing the bearing outer ring to maintain extremely high dimensional accuracy and surface quality after segmentation. The single-opening structure cleverly utilizes the elastic modulus characteristics of amorphous alloys to achieve controllable elastic deformation during assembly, ensuring both smooth installation of the rollers and structural integrity through elastic recovery force. Both processes achieve performance optimization of the discontinuous closed circle design of the bearing outer ring by precisely controlling the material microstructure and processing parameters, providing a reliable technical path for the large-scale production of high-precision crossed roller bearings.

[0054] The embodiments of this specific implementation method are all preferred embodiments of the present application and are not intended to limit the scope of protection of the present application. Therefore, all equivalent changes made based on the structure, shape, and principle of the present application, especially those involving the structural design of the bearing outer ring as a non-continuous closed circle, should be covered within the scope of protection of the present application.

Claims

1. A cross roller bearing, characterized in that: The invention comprises a bearing outer ring (1), a bearing inner ring (2) and a cylindrical roller (3); the inner circumferential surface of the bearing outer ring (1) and the outer circumferential surface of the bearing inner ring (2) are both processed with a plurality of roller grooves (4) adapted to the cylindrical rollers (3); the bearing inner ring (2) is assembled on the radial inner side of the bearing outer ring (1) in a concentric manner, and the cylindrical rollers (3) are arranged in a cross shape in the roller grooves (4) between the bearing inner ring (2) and the bearing outer ring (1); the bearing outer ring (1) is a discontinuous closed circle, and one or more fractures are arranged on the bearing outer ring (1).

2. A cross roller bearing according to claim 1, characterized in that: The bearing outer ring (1) is made of ductile iron or amorphous alloy.

3. The cross roller bearing according to claim 1, characterized in that: The bearing outer ring (1) is a continuous closed circle before controlled fracture, and one or more stress grooves (5) are processed along the circumferential direction on the outer cylindrical surface and / or two axial end surfaces; the one or more fracture openings are formed by controlled fracture along the stress grooves (5), and after fracture, the bearing outer ring (1) is a discontinuous closed circle.

4. A method for controlled fracture of a bearing outer ring, characterized in that: The following steps are involved: S201: Positioning the stress groove (5) on the bearing outer ring (1), wherein the stress groove (5) is located at one or more positions along the circumferential direction on the outer cylindrical surface and / or two axial end surfaces of the bearing outer ring (1), and concentrically sleeved on the expansion and breaking fixture seat (7); S202: Applying tension from the inner side of the bearing outer ring (1) corresponding to the stress groove (5) through the expansion and breaking fixture (7), so that the bearing outer ring (1) is controllably fractured along the stress groove (5) to form one or more fracture openings, forming a discontinuous closed circle.

5. The method for controlled fracture of a bearing outer ring according to claim 4, characterized in that: The method further comprises: S301: When a brittle fracture process is used, a directional tension is applied to a bearing outer ring (1) made of a zirconium-based or gallium-based amorphous alloy along a preset stress groove (5), and the brittle fracture characteristics of the material are utilized to cause the bearing outer ring (1) to undergo brittle fracture along the stress groove (5), forming a rough, irregular and unique fracture surface; S302: After breaking, the integrity of the fracture is checked to prevent defects and ensure the uniqueness of the joint surface of each outer ring segment and the integrity of the entire ring after splicing; S303: When using injection molding or die casting, a single or multi-layer graphene sheet is placed at one or more locations along the circumference of the mold cavity, and the cavity is divided into multiple segments. After injecting the zirconium-based or gallium-based amorphous alloy material, the material is separated along the graphene sheet by a brittle fracture effect, utilizing the high-temperature resistance and ultra-thinness of graphene, forming nano-scale gaps between the segments. S304: After the material is pressure-formed, it is taken out and the segments are spliced ​​into a whole circle, which is then ground for assembly. Alternatively, a graphene sheet is placed in the mold to form a single-opening structure. During assembly, external force is applied along the opening to open it, and the external force is released to reset it after the roller is installed.

6. A method for assembling a crossed roller bearing, characterized in that: The following steps are involved: S101: Concentrically sleeve the bearing inner ring (2) onto a magnetic fixture seat (6); S102: using manual or automated equipment to sequentially place cylindrical rollers (3) in a cross-like pattern in the roller grooves (4) outside the bearing inner ring (2), and magnetically adsorbing the cylindrical rollers (3) by a magnetic fixture (6) to prevent the cylindrical rollers (3) from falling; S103: Each segment of the bearing outer ring (1) with a non-continuous closed circular structure is spliced ​​and combined according to the unique corresponding splicing marks, and is sleeved on the outer circle side of the bearing inner ring (2) and the cylindrical roller (3); S104: Using an elastic auxiliary tool to be sleeved on the outer side of the bearing outer ring (1) after splicing, so as to maintain the splicing state of the bearing outer ring (1); S105: The assembled bearing outer ring (1), bearing inner ring (2) and cylindrical roller (3) are placed in a demagnetization device for demagnetization.

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