A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills

Abstract

This invention discloses a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills. It relates to a bearing field belonging to the technical field of green manufacturing and precision rolling equipment, and includes a thick-walled outer ring, an inner ring, double-row cylindrical rollers, and a center flange. The outer raceway of the thick-walled outer ring has an asymmetric unloading micro-zone along its axial direction away from the center flange. The center flange has inwardly recessed chamfered pressure-relieving grooves at the junction of its two guide surfaces and the bottom surface of the inner ring, creating an axially elastic suspended structure for the center flange. The inner end face of the cylindrical rollers near the center flange is a slightly convex spherical surface, and the two guide surfaces of the center flange are inclined conical surfaces radiating outwards, with tangential contact between them. This invention compensates for the bending of the outer ring under load through the asymmetric unloading micro-zone, eliminating edge stress concentration; and absorbs axial compressive force through the suspended center flange and the combination of spherical and conical surfaces, achieving adaptive load distribution and flexible pressure relief, significantly improving the bearing's service life under extreme off-center load conditions.

Description

Technical Field

[0001] This invention relates to a bearing, and more particularly to a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills, belonging to the field of green manufacturing and precision rolling equipment technology. Background Technology

[0002] Multi-roll cold rolling mills are the core equipment for rolling ultra-thin metal foil strips and are key equipment for achieving precision machining and green manufacturing of metal materials. Among them, the backing bearing is a core support component, and its performance directly affects rolling efficiency, product quality and green production level. Unlike conventional industrial bearings that are installed inside the bearing housing, the thick-walled outer ring of the backing bearing directly contacts the intermediate roll as a support roll. Under extremely high rolling force conditions, the thick-walled outer ring is in a state of stress with both ends suspended, and needs to withstand the ultimate radial load of hundreds of tons.

[0003] Existing backed bearings typically employ a thick-walled outer ring with a double-row cylindrical roller structure, and a rigid, integral solid flange in the center of the inner ring to separate the two rows of rollers. To alleviate stress concentration under heavy loads, current technologies generally use symmetrical logarithmic curves to modify the convexity of the cylindrical rollers, hoping to improve the stress distribution on the contact surface through the micro-curvature of the rollers themselves.

[0004] However, even though the outer ring of existing backed bearings has been thickened as much as possible, under extreme off-center loads, the outer ring will still undergo micron-level saddle-shaped elastic deflection, causing the two ends of the raceway inside the outer ring to tilt and shrink inward. At this time, the originally perfectly symmetrical modified rollers not only fail to play a load-equalizing role, but are also severely squeezed by the tilted raceway ends, forming an asymmetrical edge stress concentration similar to scissor closure, which in turn damages the lubricating oil film and causes premature fatigue spalling at the outer ends of the rollers.

[0005] Secondly, due to the increased stress on the outer side caused by the bending of the outer ring, the double-row cylindrical rollers generate a huge axial force towards the bearing center during dynamic operation, forcing the two rows of rollers to continuously squeeze inward. The solid flanges in the existing technology have extremely high rigidity and are completely unable to absorb or deflect this axial squeezing force; when the flat end face of the roller is subjected to high-frequency hard squeezing with the rigid flange, the contact surface will generate severe sliding friction and rapid heat generation, which can easily cause the bearing to burn and seize; under extreme loads, this huge inward squeezing force can even directly cut off the center flange from the root, causing the entire bearing to fail instantly.

[0006] In summary, existing multi-roll mill backing bearings cannot effectively address the asymmetric edge stress concentration caused by dynamic bending of the outer ring under extreme off-center load conditions. Furthermore, they cannot mitigate the risk of edge friction burns and fractures caused by internal load transfer. Therefore, there is an urgent need in this field for a high-rigidity bearing structure capable of adaptive load sharing and flexible pressure relief under microscopic deformation, in order to overcome the service life bottleneck of existing backing bearings. Summary of the Invention

[0007] This invention overcomes the shortcomings of the prior art and provides a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is: a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills, comprising:

[0009] A thick-walled outer ring, an inner ring, and a first row of cylindrical rollers and a second row of cylindrical rollers disposed between the thick-walled outer ring and the inner ring;

[0010] The middle baffle, integrally formed in the middle of the outer wall of the inner ring, is used to separate the first row of cylindrical rollers and the second row of cylindrical rollers;

[0011] The inner side of the thick-walled outer ring is provided with a first outer raceway and a second outer raceway, and the outer regions of the first outer raceway and the second outer raceway along the axial direction away from the middle stop edge are provided with asymmetric unloading micro-regions.

[0012] The outer wall of the inner ring is provided with a first inner raceway and a second inner raceway;

[0013] The two guide surfaces of the middle baffle and the bottom surface of the inner ring are respectively provided with inwardly recessed chamfered pressure relief grooves. The deepest part of the chamfered pressure relief groove is radially lower than the surface of the first inner raceway and the second inner raceway, so that the middle baffle forms a suspended structure with axial elasticity.

[0014] The inner end faces of the first and second rows of cylindrical rollers near the middle baffle are slightly convex spherical surfaces, and the two guide surfaces of the middle baffle are inclined conical surfaces that radiate radially from the inside to the outside. The slightly convex spherical surfaces and the inclined conical surfaces are in tangential contact.

[0015] In a preferred embodiment of the present invention, the sinking depth of the asymmetric unloading micro-region increases outward along the axial direction;

[0016] The maximum sinking depth of the asymmetric unloading micro-region is H. max The diameter of the first column of cylindrical rollers and the second column of cylindrical rollers is D. w The maximum sinking depth H max The relation is satisfied: 0.002D w ≤Hmax ≤0.005D w .

[0017] In a preferred embodiment of the present invention, the effective contact length between the first row of cylindrical rollers and the second row of cylindrical rollers is L. we ;

[0018] The axial starting point of the asymmetric unloading micro-region is located at the effective contact length L. we At 60% to 75% of the distance; within the interval from the center of the outer raceway to the axial starting point, the first and second outer raceways are flat cylindrical surfaces without any shaping.

[0019] In a preferred embodiment of the present invention, the axial cross-sectional profile of the chamfered pressure relief groove is an asymmetrical elliptical arc, wherein the major axis of the elliptical arc is parallel to the side wall guide surface of the middle baffle, and the minor axis is parallel to the radial direction of the inner ring.

[0020] The radial depth of the chamfered pressure relief groove is H. g The effective height of the middle retaining edge is H. r The relation 0.15H is satisfied. r ≤H g ≤0.25H r .

[0021] In a preferred embodiment of the present invention, the radius of curvature of the microconvex spherical surface is R, and the inclination angle of the inclined conical surface relative to the radial plane is . The two satisfy a geometric relationship: ;

[0022] Among them, H c Let H be the radial height from the theoretical contact point between the micro-convex spherical surface and the inclined conical surface to the inner raceway surface, satisfying: H r / 3≤H c ≤2H r / 3, so that the theoretical contact point is located within the middle one-third interval of the effective height of the middle retaining edge.

[0023] In a preferred embodiment of the present invention, the outer cylindrical surfaces of the first row of cylindrical rollers and the second row of cylindrical rollers are provided with logarithmic curve convexity modification areas;

[0024] The logarithmic curve convexity shaping area has a smaller shaping drop on the side closer to the middle baffle than on the side farther from the middle baffle, forming an asymmetric roller convexity that matches the asymmetric unloading micro-area.

[0025] In a preferred embodiment of the present invention, a plurality of lubricating oil holes are provided radially through the inner ring, and the external outlet of the lubricating oil holes is directly connected to the bottom of the chamfered pressure relief groove;

[0026] When the middle retaining edge is subjected to load and undergoes axial elastic deformation, the volume of the chamfered pressure relief groove changes periodically, creating a pumping effect on the lubricating oil in the lubricating oil hole.

[0027] In a preferred embodiment of the present invention, an inwardly recessed oil storage micro-pit is provided at the center of the micro-convex spherical surface of the first row of cylindrical rollers and the second row of cylindrical rollers;

[0028] The edge of the oil storage micro-pit smoothly transitions to the micro-convex spherical surface, providing lubricant reserve when the micro-convex spherical surface contacts the inclined conical surface.

[0029] In a preferred embodiment of the present invention, the axial base width of the middle retaining edge is W. b The diameter of the first column of cylindrical rollers and the second column of cylindrical rollers is D. w ;

[0030] The axial base width W b The relation is satisfied: 0.08D w ≤W b ≤0.12D w .

[0031] In a preferred embodiment of the present invention, the thick-walled outer ring is made of high-carbon chromium bearing steel and has undergone carbonitriding treatment;

[0032] The effective hardened layer depth from the outer surface of the thick-walled outer ring to the center is D. out The effective hardened layer depth from the surface of the first and second outer raceways to the core is D. in The two satisfy the following relationship: D out ≥1.5D in .

[0033] This invention addresses the shortcomings of the prior art and has the following beneficial effects:

[0034] This invention incorporates asymmetric unloading micro-zones along the outer regions of the first and second outer raceways of the thick-walled outer ring, away from the center flange. This precisely compensates for the saddle-shaped microelastic deflection of the thick-walled outer ring under ultimate rolling force. When the outer ring bends under load, the previously sunken micro-zones are flattened, eliminating the scissor-like compression of the outer ends of the cylindrical rollers caused by the bending raceways, resulting in uniform stress distribution along the entire length of the rollers. Conventional symmetrical roller shaping in existing technologies is completely inadequate to handle this dynamic asymmetric deformation, easily leading to severe edge stress concentration. This invention, through this adaptive geometric compensation, completely eliminates the risk of early fatigue spalling at the outer edges, significantly improving the overall dynamic rigidity and service life of the bearing under ultimate off-center loads.

[0035] The inner ring's center flange features inwardly recessed, chamfered pressure-relieving grooves at the junction of the guide surfaces and bottom surface, with a radial depth lower than the inner raceway surface. This creates an axially elastic suspension structure for the center flange. When the outer ring bends, causing the load to shift towards the bearing center and forcing the double-row rollers to compress inward, this suspension structure absorbs the enormous axial compressive force through the micro-elastic tilt generated by the root pressure-relieving grooves. This transforms the destructive hard compression into elastic potential energy, achieving adaptive load sharing between the two rows of rollers. In contrast, existing rigid solid flanges often suffer severe hard-on-hard collisions, jamming, or even root fracture when facing this internal load transfer. This mechanism not only effectively avoids the fatal failure of flange fracture but also provides a significant buffer space for dynamic force balance within the bearing.

[0036] The inner end faces of the first and second rows of cylindrical rollers near the center flange are designed as slightly convex spherical surfaces, which tangentially contact the inclined conical surface of the center flange, which radiates radially from the inside out. This ensures a precise point-to-line transition contact between the roller end faces and the flange, and naturally forms wedge-shaped openings around the contact area for lubricating oil entrainment. This transforms traditional sliding friction into a low-friction state of mixed rolling and micro-sliding, preventing stress concentration at the contact edges even when the center flange elastically tilts. Compared to existing technologies where the surface contact between the flat end face and the flat flange is prone to scratching the oil film and causing high-temperature burns under load and skew, the contact structure of this invention maintains the stability of hydrodynamic lubrication throughout dynamic deformation, significantly reducing frictional heat generation under high-speed, heavy-load conditions.

[0037] The lubricating oil hole, radially penetrating the inner ring, has its external outlet directly connected to the bottom of the chamfered pressure relief groove. When the bearing operates at high speed and the middle flange undergoes high-frequency microscopic axial elastic deformation due to alternating pressure from the rollers, the internal volume of the chamfered pressure relief groove periodically contracts and expands, creating a micro-pumping effect within the groove. This forces the lubricating oil from the lubricating oil hole out and precisely sprays it onto the contact area between the roller end face and the flange. Existing technologies typically rely on passive splash lubrication, making it extremely difficult for lubricating oil to penetrate the tightly compressed friction area of ​​the flange. This invention, by achieving active fluid pumping, fundamentally solves the problem of insufficient lubrication in the middle flange area.

[0038] The cylindrical roller's micro-convex spherical surface is further reinforced with an inwardly recessed, smoothly transitioning oil-retaining micro-pit at its center. This micro-pit continuously stores and releases trace amounts of lubricating oil during operation, providing a highly reliable local lubricating oil reserve for high-frequency dynamic contact points and preventing instantaneous oil shortage. Compared to the existing technology where smooth spherical end faces easily expel lubricating oil from the contact surface under extreme compression, leading to dry friction, the oil-retaining micro-pit of this invention, combined with the aforementioned pumping effect, forms a self-lubricating circulation system, endowing the bearing contact end faces with extremely high wear resistance and burn resistance.

[0039] The thick-walled outer ring is made of high-carbon chromium bearing steel and undergoes carbonitriding treatment. The effective hardened layer depth from its outer surface to the core is strictly controlled to be greater than or equal to 1.5 times the hardened layer depth of the inner raceway surface. This allows the outer ring to have extremely high wear resistance on the outer surface that directly contacts the roll, while its core and inner side retain excellent impact toughness, giving the thick-walled outer ring a perfect physical basis for adapting to saddle-shaped elastic bending. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the overall structure of a high-rigidity double-row cylindrical roller backing bearing for a multi-roll mill according to the present invention.

[0042] Figure 2 This is a schematic diagram of the internal structure of the present invention after half-section.

[0043] Figure 3 This is an enlarged view of the structure of the thick-walled outer ring and inner ring after half-section of the present invention;

[0044] Figure 4 This is a schematic diagram of the structure of the oil storage micro-pit of the present invention;

[0045] Figure 5 This is a partially enlarged cross-sectional view of the outer raceway and cylindrical rollers of the present invention;

[0046] Figure 6 This is a front view of the cylindrical roller used in this invention to demonstrate the effective contact length;

[0047] Figure 7 This is the present invention. Figure 3 Enlarged view of point A in the middle;

[0048] In the diagram: 1. Thick-walled outer ring; 2. Inner ring; 3. First row of cylindrical rollers; 4. Second row of cylindrical rollers; 5. Middle flange; 6. First outer raceway; 7. Second outer raceway; 8. Asymmetric unloading micro-zone; 9. First inner raceway; 10. Second inner raceway; 11. Chamfered pressure relief groove; 12. Lubricating oil hole; 13. Oil reservoir pit; 14. Axial starting point. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein. Therefore, the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0051] In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application 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, and therefore should not be construed as limiting the scope of protection of this application. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0052] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art will understand the specific meaning of the above terms in this application based on the specific circumstances.

[0053] The specific implementation and working process of the present invention will be described in detail below with reference to the accompanying drawings and several embodiments. It should be noted in advance that, in order to clearly illustrate the microscopic shaping features of the rollers, the micro-area sinking features of the outer raceway, and the minute gaps and angles between the components in the present invention, the accompanying drawings exaggerate the microscopic dimensional differences, sinking depths, and tilting angles. In actual industrial manufacturing and assembly, the aforementioned shaping differences, sinking depths, and elastic tilting amounts are all at the micrometer level, and their specific dimensions are strictly constrained by the mathematical relationships defined in the claims of the present invention. Therefore, the exaggerated proportions in the accompanying drawings should not be construed as limitations on the actual physical dimensions and scope of protection of the present invention.

[0054] like Figures 1 to 4 As shown, a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills includes:

[0055] Thick-walled outer ring 1, inner ring 2, and a first row of cylindrical rollers 3 and a second row of cylindrical rollers 4 disposed between the thick-walled outer ring 1 and inner ring 2;

[0056] The middle baffle 5 is integrally formed in the middle of the outer wall of the inner ring 2, and is used to separate the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4.

[0057] The inner side of the thick-walled outer ring 1 is provided with a first outer raceway 6 and a second outer raceway 7. The first outer raceway 6 and the second outer raceway 7 are provided with an asymmetric unloading micro-region 8 in the outer region away from the middle baffle 5 along the axial direction.

[0058] The outer wall of the inner ring 2 is provided with a first inner raceway 9 and a second inner raceway 10;

[0059] The two guide surfaces of the middle baffle 5 and the bottom surface of the inner ring 2 are respectively provided with inwardly recessed chamfered pressure relief grooves 11. The deepest part of the chamfered pressure relief grooves 11 is radially lower than the surfaces of the first inner raceway 9 and the second inner raceway 10, so that the middle baffle 5 forms a suspended structure with axial elasticity.

[0060] The inner end faces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 near the middle baffle 5 are slightly convex spherical surfaces. The two guide surfaces on both sides of the middle baffle 5 are inclined conical surfaces that radiate radially from the inside to the outside. The slightly convex spherical surfaces and the inclined conical surfaces are in tangential contact.

[0061] The core innovation of this invention lies in breaking away from the traditional design thinking of pursuing absolute rigidity support in high-rigidity bearings. It integrates the asymmetric unloading micro-zone 8, the suspended middle flange 5, and the contact structure of the micro-convex spherical surface and the inclined conical surface into a dynamic response system. Its basic principle is to actively utilize the micro-elastic deformation of the thick-walled outer ring 1 under extreme off-center load. Through the preset geometric compensation space and flexible relief structure, the destructive hard compression is transformed into elastic potential energy, thereby achieving adaptive load equalization and flexible pressure relief in dynamic operation, and completely solving the bearing failure problem caused by edge stress concentration and internal load transfer.

[0062] The technical solution of the present invention will be analyzed in depth below from three dimensions: mechanical synergy, lubrication synergy, and material synergy, in conjunction with specific embodiments.

[0063] Example 1: In the working environment of a multi-roll cold rolling mill, the thick-walled outer ring 1 of the backing bearing directly contacts the intermediate roll as a support roll. When the existing backing bearing is subjected to a maximum radial load of hundreds of tons, its thick-walled outer ring 1 will inevitably undergo micron-level saddle-shaped elastic deflection, which causes the two ends of the first outer raceway 6 and the second outer raceway 7 inside the thick-walled outer ring 1 to tilt and shrink towards the bearing center. At this time, the cylindrical roller, which was originally in an ideal line contact state, will be severely squeezed by the tilted raceway at its outer end, forming an asymmetric edge stress concentration similar to scissor closure, which will destroy the lubricating oil film at the roller end, resulting in direct metal-to-metal friction and causing early fatigue spalling at the outer end of the roller.

[0064] Meanwhile, the saddle-shaped bending of the thick-walled outer ring 1 also changes the direction of the internal force vector; the dramatic increase in external force causes the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 to generate a huge axial component force pointing towards the bearing center during dynamic operation, forcing the two rows of cylindrical rollers to continuously squeeze the middle flange 5 inward. In the prior art, the middle flange 5 is usually a solid rigid structure, which is completely unable to absorb or deflect this axial extrusion force. When the end face of the cylindrical rollers is subjected to high-frequency hard extrusion with the rigid middle flange 5, the contact surface will generate severe sliding friction and rapid heat generation, which can easily cause the bearing to burn and seize, leading to the instantaneous failure of the entire bearing.

[0065] To fundamentally solve the aforementioned problems of edge stress concentration and internal load transfer, this embodiment involves the coordinated modification of the raceway morphology of the thick-walled outer ring 1 and the root structure of the flange 5 in the inner ring 2.

[0066] Preferably, on the inner side of the thick-walled outer ring 1, the first outer raceway 6 and the second outer raceway 7 are not conventional flat cylindrical surfaces.

[0067] Preferably, an asymmetric unloading micro-region 8 is provided in the outer region away from the middle baffle 5 along the axial direction, that is, in the region near the two ends of the thick-walled outer ring 1. The sinking depth of the asymmetric unloading micro-region 8 has a smooth increasing trend along the axial direction to the outside. This is mainly manifested in that the first outer raceway 6 and the second outer raceway 7 remain straight in the inner region near the middle baffle 5, while in the outer region away from the middle baffle 5, they exhibit a gradually expanding micro-flare shape.

[0068] Under static or light load conditions, there is a micron-level gap between the outer ends of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 and the asymmetric unloading micro-region 8. The first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 mainly rely on the middle and inner sections to bear the load.

[0069] When the bearing enters the extreme off-center load condition, the thick-walled outer ring 1 undergoes saddle-shaped bending, and its two ends inevitably tilt and sink inward; at this time, the pre-set asymmetric unloading micro-zone 8 just compensates for the sinking of the outer ring end.

[0070] At the moment of dynamic stress, the originally outward expanding micro-area is bent and deformed flattened, forming a perfect parallel line contact with the outer cylindrical surface of the cylindrical roller; by utilizing the elastic deformation of the material, the present invention transforms the geometric gap under static conditions into a uniform bearing surface under dynamic conditions, eliminating the scissor-like compression of the outer end of the cylindrical roller by the curved raceway, and realizing adaptive load equalization of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 along the entire length.

[0071] To ensure that the asymmetric unloading micro-region 8 can effectively eliminate edge stress without causing a decrease in the overall rigidity of the bearing, this embodiment imposes strict parameter limitations on its sinking depth and starting position.

[0072] Preferably, the maximum sinking depth of the asymmetric unloading micro-region 8 is set to H. max The diameter of the first column of cylindrical rollers 3 and the second column of cylindrical rollers 4 is set to D. w The two satisfy the mathematical relationship: 0.002D w ≤H max ≤0.005D w .

[0073] The maximum sinking depth is less than 0.002 times the roller diameter. Under the ultimate rolling force, the compensation amount of the micro-area will not be enough to offset the bending amount of the thick-walled outer ring 1, and stress concentration will still occur at the edge of the roller.

[0074] If the maximum subsidence depth is greater than 0.005 times the roller diameter, the outer end of the roller will be suspended for a long time under normal operation or medium load. This will not only weaken the overall support rigidity of the bearing, but also cause the load to be excessively concentrated in the middle section of the roller, leading to new fatigue damage.

[0075] Preferably, the effective contact length of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 is set to L. we ,like Figure 6 As shown, the effective contact length L we The axial starting point 14 of the asymmetric unloading micro-region 8 is precisely controlled at the effective contact length L after removing the straight cylindrical section after the end trimming or chamfering of the cylindrical roller. we 60% to 75% of the area.

[0076] Combination Figure 5 and Figure 6 As shown, the aforementioned 60% to 75% ratio is calculated from the inner end of the cylindrical roller near the center flange 5 (i.e., the 0% position) and extended to the outer end away from the center flange 5 (i.e., the 100% position). Within the interval from the center of the first outer raceway 6 and the second outer raceway 7 to the axial starting point 14, the raceway remains an unmodified, flat cylindrical surface; while the area extending outward from the axial starting point 14 is the downwardly concave, asymmetric unloading micro-region 8.

[0077] Preferably, within the section from the end of the first outer raceway 6 and the second outer raceway 7 near the center flange 5 to the axial starting point 14, the raceways remain as unmodified, flat cylindrical surfaces. This segmented raceway design ensures that when the bearing is subjected to radial loads, at least 60% of the roller area is in perfect flat direct contact, guaranteeing the load-bearing capacity of the foundation; only in the area of ​​25% to 40% on the outer side of the rollers, i.e., the dangerous area where saddle-shaped bending causes a sharp increase in stress, does the asymmetric unloading micro-region 8 begin to play its flexible avoidance and compensation role.

[0078] Preferably, at the junction of the guide surfaces on both sides of the middle baffle 5 and the bottom surface of the inner ring 2, inwardly recessed chamfered pressure relief grooves 11 are respectively processed, the deepest point of which is significantly lower than the surface of the first inner raceway 9 and the second inner raceway 10 in the radial direction; by hollowing out the material at the root, the middle baffle 5 forms a suspension structure with microscopic axial elasticity.

[0079] Specifically, when the thick-walled outer ring 1 bends, it forces the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 to generate huge axial force and squeeze the middle flange 5 inward. Under the action of huge axial extrusion force, the chamfered pressure relief groove 11 at the root of the middle flange 5 allows the middle flange 5 to undergo micron-level elastic tilting and yielding. This micro-elastic tilting is like a high-strength spring sheet, absorbing and buffering the destructive extrusion force transmitted by the rollers, and converting the hard destructive force into elastic potential energy.

[0080] When the extrusion pressure of the rollers decreases due to load fluctuations, the middle baffle 5 can return to its original position by relying on the elasticity of the material. This not only completely avoids the fatal failure of root fracture caused by stress concentration in the middle baffle 5, but also provides a great buffer space for the dynamic force balance between the two rows of cylindrical rollers.

[0081] Preferably, such as Figure 7 As shown, the axial cross-sectional profile of the chamfered pressure relief groove 11 is designed as an asymmetrical elliptical arc. The major axis of this elliptical arc is parallel to the side wall guide surface of the middle baffle 5, and the minor axis is parallel to the radial direction of the inner ring 2. Compared with the conventional semi-circular groove, the asymmetrical elliptical arc design can more smoothly guide the stress flow to the thick substrate at the bottom of the inner ring 2, avoiding the generation of new stress concentration points at the bottom of the groove.

[0082] Furthermore, the radial depth of the chamfered pressure relief groove 11 is set to H. g The effective height of the middle retaining edge 5 is set to H. r ,like Figure 7 As shown, the radial depth H g The effective height H is the vertical distance from the flat surface of the first inner raceway 9 or the second inner raceway 10 down to the deepest point of the chamfered pressure relief groove 11; r The vertical distance from the aforementioned flat surface upwards to the top of the guide surface of the middle retaining edge 5, as a reference, satisfies the following relationship: 0.15H r ≤H g ≤0.25H r .

[0083] Specifically, when the depth of the pressure relief groove is less than 15% of the effective height, too much material is retained at the five roots of the middle baffle, resulting in insufficient suspension elasticity and an inability to generate effective tilting and yielding during roller extrusion, thus the problem of hard extrusion still exists.

[0084] When the depth of the pressure relief groove is greater than 25% of the effective height, although the elasticity is excellent, the cross-sectional area of ​​the five roots of the middle baffle is too small, and fatigue fracture is likely to occur when subjected to extreme alternating loads.

[0085] During the micro-elastic tilting and yielding process of the aforementioned suspended middle flange 5, if the flat-end roller commonly used in the prior art is used in conjunction with the flat flange, when the middle flange 5 is tilted under force, the flat contact surface will be instantly destroyed, and the end edge of the roller will be stuck on the tilted flange surface like a blade. This will not only lead to local stress concentration, but also scratch the lubricating oil film on the contact surface, causing severe dry friction and high-temperature burns.

[0086] In order to maintain an ideal contact state during dynamic deformation, this embodiment has carried out special geometric shape design on the inner end faces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4, as well as the two guide faces on both sides of the middle flange 5.

[0087] Specifically, the inner end faces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 near the center flange 5 are machined into slightly convex spherical surfaces, while the guide surfaces on both sides of the center flange 5 are not planes perpendicular to the axis, but are designed as inclined conical surfaces radiating radially from the inside out. In the assembled and operating state, the slightly convex spherical surfaces of the cylindrical rollers and the inclined conical surfaces of the center flange 5 are in tangential contact.

[0088] When the suspended middle baffle 5 tilts elastically under the action of huge axial compressive force, since the end face of the roller is spherical, the spherical surface and the tilted plane always maintain a precise "point-line" transition contact; no matter how small the tilt angle of the middle baffle 5 changes, the contact point only slips slightly on the spherical surface, and there will never be edge jamming or stress concentration.

[0089] Even more ingeniously, this spherical and conical contact structure naturally forms a V-shaped wedge opening around the theoretical contact point. When the bearing operates at high speed, this wedge opening can draw surrounding lubricating oil into the contact area, thereby transforming the traditional pure sliding friction into a mixed low-friction state of rolling and micro-sliding. This maintains the stability of hydrodynamic lubrication throughout the dynamic deformation process and significantly reduces frictional heat generation under high-speed and heavy-load conditions.

[0090] To ensure the reliability of this dynamic contact mechanism, this embodiment imposes extremely strict mathematical constraints on the geometric parameters of the microconvex spherical surface and the inclined conical surface.

[0091] Let the radius of curvature of the slightly convex sphere be R, and the angle of inclination of the inclined cone relative to the radial plane be . Both must satisfy the geometric relationship: .

[0092] The theoretical contact point height between the roller and the center flange 5 is determined using the above formula. According to spatial geometry principles, a sphere with radius R rests against a surface with an angle of inclination of... On the inclined plane, the only point of tangency between the two is vertically distancing from the bottom of the inclined plane. .

[0093] In this invention, H c This represents the radial height from the theoretical contact point to the inner raceway surface.

[0094] Using the above formula, the present invention precisely anchors the contact point between the roller and the middle flange 5 at a height of H. c The location.

[0095] Furthermore, this embodiment defines the radial height H. c The following relation must be satisfied: H r / 3≤H c ≤2Hr / 3, where H r This is the effective height of the middle retaining edge 5.

[0096] The above formula ensures that the theoretical contact point is strictly controlled within the middle 1 / 3 of the effective height of the middle baffle 5.

[0097] If the contact point is too high, that is, the roller is pressed at the top of the middle flange 5, the lever arm is too long, and the huge axial component force can easily use the leverage effect to pry the middle flange 5 directly from the root.

[0098] Conversely, if the contact point is too low, i.e. the roller is pressed at the root of the middle retaining edge 5, the lever arm is too short and the pressing force of the roller cannot push the middle retaining edge 5 to tilt effectively. The flexible yielding mechanism provided by the aforementioned chamfered pressure relief groove 11 will completely fail.

[0099] Only when the contact point is precisely locked in the middle 1 / 3 section can the suspended middle baffle 5 perfectly exert its elastic buffering function, so that it will not be pried off and can effectively absorb axial compressive force.

[0100] As a further synergy and double insurance for the asymmetric unloading micro-region 8 of the thick-walled outer ring 1, this embodiment also performs logarithmic curve convexity modification on the outer cylindrical surfaces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4.

[0101] Specifically, the convexity modification zone of the logarithmic curve has a significantly smaller modification drop on the side closer to the middle baffle 5 than on the side farther from the middle baffle 5, thereby enabling the convexity of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 to form a matching relationship with the asymmetric unloading micro-region 8 of the thick-walled outer ring 1.

[0102] Under extreme off-center load, the outer side of the thick-walled outer ring 1 has the largest bending and sinking. Therefore, the outer sides of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 are made to avoid the load by using a larger shaping difference.

[0103] Unlike the modified height difference on the outer sides of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4, the inner sides of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 employ a smaller modified height difference to ensure sufficient contact area and support rigidity. This dual geometric compensation, which involves hollowing out the outer ring and asymmetrically modifying the rollers, effectively solves the stress concentration problem at the outer edge.

[0104] Example 2: This example further optimizes the lubrication system inside the bearing, based on Example 1.

[0105] When the bearing is under high-speed, heavy-load conditions, the middle flange 5 is subjected to extremely high-frequency alternating compression from the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4. Under this high-frequency micro-oscillation state, the contact area between the middle flange 5 and the end faces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 is subjected to extremely tight pressure. Existing backed bearings typically rely on passive splash lubrication, i.e., the rotation of the rollers carries the lubricating oil. However, under enormous centrifugal force and tight contact pressure, the splashed lubricating oil has great difficulty actively penetrating into the friction area between the middle flange 5 and the roller end faces. This still poses a risk of micro-wear even under momentary oil shortage conditions.

[0106] To address the problem of insufficient lubrication in the middle flange area 5, this embodiment utilizes the dynamic deformation of the mechanical structure in Embodiment 1 to construct an active self-lubricating microcirculation system.

[0107] Preferably, a plurality of lubricating oil holes 12 are machined radially through the inner ring 2.

[0108] Specifically, the internal inlets of these lubricating oil holes 12 are connected to the oil supply circuit of the bearing, while their external outlets are directly connected to the bottom of the chamfered pressure relief groove 11 at the bottom of the inner ring 2.

[0109] Preferably, an inwardly recessed oil storage pit 13 is further processed at the center of the micro-convex spherical surface of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4; the edge of the oil storage pit 13 and the micro-convex spherical surface are designed with a smooth transition to avoid sharp-angle scratches.

[0110] During the high-speed operation of the bearing, when the thick-walled outer ring 1 is bent under load and forces the rollers to squeeze inward, the middle baffle 5 is subjected to axial elastic tilting. At this time, the chamfered pressure relief groove 11 located at the root of the middle baffle 5 is compressed, and its internal volume decreases instantaneously. When the rollers pass through the bearing area and the squeezing force disappears, the middle baffle 5 returns to its original position by elasticity, and the chamfered pressure relief groove 11 expands accordingly, and its internal volume increases instantaneously.

[0111] When the pressure relief groove expands, it draws in lubricating oil from the lubricating oil hole 12; when the pressure relief groove contracts under pressure, it generates a strong micro-pumping effect, forcibly squeezing out the lubricating oil in the groove. The lubricating oil that is forcibly pumped out rises along the side wall of the middle baffle 5 and is precisely sprayed onto the contact area between the roller end face and the middle baffle 5.

[0112] The lubricating oil, forcibly pumped out by the chamfered pressure relief groove 11, is precisely sprayed and converged into the oil storage micro-pits 13 on the end faces of the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 under the combined action of centrifugal force and capillary effect. Under extreme heavy-load and off-center loading conditions, the contact stress between the roller end face and the inclined conical surface of the middle flange 5 is extremely high. Ordinary lubricating oil film is easily ruptured instantly, leading to brief boundary friction or even dry friction. However, due to the presence of the oil storage micro-pits 13, even at the moment when the contact surface is under the tightest pressure, a small amount of lubricating oil is still safely sealed inside the micro-pits.

[0113] As the cylindrical rollers rotate at high speed, the lubricating oil inside the oil storage pit 13 will overflow outward along the smooth transition edge of the pit under the drive of centrifugal force, and be directly carried into the wedge-shaped opening formed by the roller's micro-convex spherical surface and the inclined conical surface of the middle baffle 5, thereby ensuring that the core area of ​​the contact surface between the first row of cylindrical rollers 3 and the second row of cylindrical rollers 4 and the middle baffle 5 can be continuously replenished with lubricating oil.

[0114] Example 3: Preferably, the thick-walled outer ring 1 is made of high-carbon chromium bearing steel and undergoes a carbonitriding process.

[0115] More importantly, the effective hardened layer depth from the outer surface of the thick-walled outer ring 1 to the core is D. out The effective hardened layer depth from the surface of the first outer raceway 6 and the second outer raceway 7 to the core is set to D. in The two satisfy the mathematical relationship: D out ≥1.5D in .

[0116] By requiring the effective hardened layer depth D of the outer surface out It is at least 1.5 times the effective hardened layer depth Din of the inner raceway, thus creating an asymmetric hardness gradient distribution inside the thick-walled outer ring 1.

[0117] The extremely deep hardened layer on the outer surface effectively resists the enormous contact fatigue caused by the external rolls and prevents deep spalling caused by subsurface shear stress; while the shallower hardened layer on the inner raceway surface, after meeting the wear resistance required for the rolling contact of the cylindrical rollers, quickly transitions to the matrix, thereby preserving the extensive tough core area inside the thick-walled outer ring 1 to the greatest extent.

[0118] Through carbonitriding, nitrogen is incorporated into the surface layer of the thick-walled outer ring 1, thereby refining the surface martensite structure and retaining an appropriate amount of retained austenite. This retained austenite, combined with the unhardened tough core of the thick-walled outer ring 1, improves the overall impact toughness and microscopic plastic deformation capacity of the thick-walled outer ring 1.

[0119] Based on the aforementioned asymmetric material structure with a deep outer surface hardened layer, a shallow inner raceway hardened layer, and high-toughness core, the thick-walled outer ring 1 possesses the mechanical basis to adapt to saddle-shaped microelastic flexure. This allows the thick-walled outer ring 1 to effectively cooperate with the asymmetric unloading micro-region 8 to achieve load sharing when subjected to extreme eccentric loads and undergoing micron-level bending deformation. Furthermore, it can return to its original shape after the load is removed, thereby reducing the risk of brittle fracture and fatigue failure of the thick-walled outer ring 1.

[0120] In summary, this invention provides a high-rigidity double-row cylindrical roller backing bearing for multi-roll mills. Through the synergy of the asymmetric unloading micro-zone 8 of the thick-walled outer ring 1 and the suspended center flange 5 of the inner ring 2, the destructive hard extrusion under extreme off-center load is converted into elastic potential energy, achieving adaptive load equalization and flexible pressure relief. Furthermore, the contact fit between the micro-convex spherical surface and the inclined conical surface avoids edge stress concentration during dynamic deformation. The high-frequency micro-elastic tilt of the center flange 5 drives the chamfered pressure relief groove 11 to generate a micro-pumping effect, which, combined with the oil reservoir micro-pit 13, achieves active hydrodynamic lubrication in the contact area. Finally, the carbonitriding treatment of high-carbon chromium bearing steel and the gradient design of the asymmetric hardening layer provide a physical basis for the aforementioned micro-elastic flexural deformation, exhibiting both high wear resistance and high impact toughness. The interdependent and synergistic effects of these technical features effectively solve the technical problems of edge spalling, flange fracture, and friction burns that easily occur in existing backing bearings under extreme off-center load conditions, significantly improving the overall service life and operational reliability of the bearing under extreme conditions.

[0121] Based on the preferred embodiments of the present invention described above, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills, characterized in that, include: Thick-walled outer ring (1), inner ring (2), and a first row of cylindrical rollers (3) and a second row of cylindrical rollers (4) disposed between the thick-walled outer ring (1) and the inner ring (2); The middle baffle (5) is integrally formed in the middle of the outer wall of the inner ring (2) and is used to separate the first column of cylindrical rollers (3) and the second column of cylindrical rollers (4); The thick-walled outer ring (1) has a first outer raceway (6) and a second outer raceway (7) on its inner side. The first outer raceway (6) and the second outer raceway (7) have an asymmetric unloading micro-region (8) in the outer region away from the middle stop edge (5) along the axial direction. The outer wall of the inner ring (2) is provided with a first inner raceway (9) and a second inner raceway (10); The two guide surfaces of the middle baffle (5) and the bottom surface of the inner ring (2) are respectively provided with inwardly recessed chamfered pressure relief grooves (11). The deepest part of the chamfered pressure relief groove (11) is radially lower than the surface of the first inner raceway (9) and the second inner raceway (10), so that the middle baffle (5) forms a suspended structure with axial elasticity. The inner end faces of the first row of cylindrical rollers (3) and the second row of cylindrical rollers (4) near the middle baffle (5) are slightly convex spherical surfaces. The two guide surfaces of the middle baffle (5) are inclined conical surfaces that radiate radially from the inside to the outside. The slightly convex spherical surfaces and the inclined conical surfaces are in tangential contact. The sinking depth of the asymmetric unloading micro-region (8) increases outward along the axial direction; The maximum sinking depth of the asymmetric unloading micro-region (8) is H. max The diameter of the first column of cylindrical rollers (3) and the second column of cylindrical rollers (4) is D. w The maximum sinking depth H max The relation is satisfied: 0.002D w ≤H max ≤0.005D w .

2. The high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The effective contact length between the first row of cylindrical rollers (3) and the second row of cylindrical rollers (4) is L. we ; The axial starting point (14) of the asymmetric unloading micro-region (8) is located at the effective contact length L. we At 60% to 75% of the distance; within the interval from the center of the outer raceway to the axial starting point (14), the first outer raceway (6) and the second outer raceway (7) are flat cylindrical surfaces without any shaping.

3. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The axial cross-sectional profile of the chamfered pressure relief groove (11) is an asymmetrical elliptical arc, with the major axis of the elliptical arc parallel to the side wall guide surface of the middle baffle (5) and the minor axis parallel to the radial direction of the inner ring (2). The radial depth of the chamfered pressure relief groove (11) is H. g The effective height of the middle retaining edge (5) is H. r The relation 0.15H is satisfied. r ≤H g ≤0.25H r .

4. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The radius of curvature of the microconvex spherical surface is R, and the angle of inclination of the inclined conical surface relative to the radial plane is . The two satisfy a geometric relationship: ; Among them, H c Let H be the radial height from the theoretical contact point between the micro-convex spherical surface and the inclined conical surface to the inner raceway surface, satisfying: H r / 3≤H c ≤2H r / 3, so that the theoretical contact point is located within the middle third of the effective height of the middle retaining edge (5).

5. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The outer cylindrical surfaces of the first row of cylindrical rollers (3) and the second row of cylindrical rollers (4) are provided with logarithmic curve convexity modification areas; The logarithmic curve convexity shaping area has a smaller shaping drop on the side closer to the middle baffle (5) than on the side farther from the middle baffle (5), forming an asymmetric roller convexity that matches the asymmetric unloading micro-area (8).

6. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The inner ring (2) is provided with a plurality of lubricating oil holes (12) extending radially through it, and the external outlet of the lubricating oil holes (12) is directly connected to the bottom of the chamfered pressure relief groove (11); When the middle baffle (5) is subjected to axial elastic deformation under load, the volume of the chamfered pressure relief groove (11) changes periodically, forming a pumping effect on the lubricating oil in the lubricating oil hole (12).

7. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The first row of cylindrical rollers (3) and the second row of cylindrical rollers (4) have an inwardly recessed oil storage pit (13) at the center of their micro-convex spherical surfaces. The edge of the oil storage micro-pit (13) smoothly transitions to the micro-convex spherical surface, providing a lubricating oil reserve when the micro-convex spherical surface contacts the inclined conical surface.

8. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The axial base width of the middle retaining edge (5) is W b The diameter of the first column of cylindrical rollers (3) and the second column of cylindrical rollers (4) is D. w ; The axial base width W b The relation is satisfied: 0.08D w ≤W b ≤0.12D w .

9. A high-rigidity double-row cylindrical roller backing bearing for multi-roll mills according to claim 1, characterized in that, The thick-walled outer ring (1) is made of high-carbon chromium bearing steel and has undergone carbonitriding treatment; The effective hardened layer depth from the outer surface of the thick-walled outer ring (1) to the core is D. out The effective hardened layer depth from the surface of the first outer raceway (6) and the second outer raceway (7) to the core is D. in The two satisfy the following relationship: D out ≥1.5D in .

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