Bearing temperature reduction by bushing modification

Abstract

A novel bushing (300) is disclosed for use in a bearing in a rolling mill, where a feature of length Z is introduced on an inner portion (201) of an outer surface (303) of the bushing (300), where the feature introduced allows the bushing (300) to deflect as the load at a maximum radial deflection of 6 mm increases. Introduced features cope with elevated temperatures on the interior side of the bushing (300) by allowing the bushing to deflect as the load increases.

Description

Technical Field

[0001] The present invention generally relates to the field of rolling mill support bearings, in particular oil film support bearings. More specifically, the present invention relates to the improvement of the temperature profile within the bearing during operation. Background Art

[0002] Figure 1A - Figure 1B A known oil film bearing assembly as described in US Patent 4,772,137 is depicted. The standard in the industry is a cylindrical bushing (sometimes called a bearing) and a cylindrical OD / tapered ID sleeve (sometimes called a journal). The bushing has a cylindrical OD with a tight fit within the bearing seat (bearing housing), and the sleeve has an internal taper angle that precisely matches the roll.

[0003] Patent '137 describes the following typical rolling mill oil film bearing. Roll 10 has a neck section 12. Neck section 12 can be conical, as shown in Figure 1 (A), or it can be cylindrical in some alternative configurations. Sleeve 14 is received on neck section 12 and fixed relative to neck section 12. The exterior of the sleeve defines a journal surface 16 of the roll neck. Bushing 18 has an inner bearing surface 20 surrounding the journal surface 16 and rotatably supporting the journal surface 16. The bushing is contained by a bearing seat 22 and fixed within the bearing seat 22. The bearing seat is closed at the outer end by an end plate 24 and a cover 26. A seal assembly 28 is provided between the roll and the inner end of the bearing seat 22.

[0004] During normal operation of the machine, when the rolls rotate at an appropriate speed for full hydrodynamic operation, a continuous flow of oil is fed through one of the groups of passages 29 in the bearing seat, feed openings 30 in the bushing and rebored holes 32 in the bearing surface 20. From here, the oil enters between the bearing surface 20 and the rotating journal surface 16 so as to pass through the bearing load area "Z" and the hydrodynamic length "L H "A slightly wedge-shaped oil film 34 is formed which is maintained by fluid dynamics, the length of the bushing interacting with the sleeve and supporting the oil film. In Figure 1(A), the load is applied by the roll at "SF". The load is resisted by the force "F" on the bearing seat. The load area is on the same side as the resisting force "F". The pressure curve at the load area is schematically depicted at "P" in Figure 1(A).

[0005] When the rolls are either not rotating or are rotating at a speed slower than required to create and maintain the hydrodynamic oil film 34, conventional hydrodynamic methods are employed to create the necessary oil film between the journal and bearing surfaces.

[0006] Oil is continuously drained from between the journal surface 16 and the bearing surface 20 at both the outer and inner ends of the load zone. Oil draining from the inner port enters an inner sump 36, which is surrounded by the seal assembly 28 and the adjacent surfaces of the bearing seat, bushing and rollers. Oil draining from the outer port enters an outer sump 38, which is surrounded by the end plate 24 and the bearing seat 22. The reservoirs 36, 38 are interconnected by one or more passages 40 drilled through the bearing seat, and the outer sump 38 is connected to a conventional lubrication system (not shown) that filters the oil, cools the oil, and recirculates the oil back to the bearing for reintroduction between the bearing surface 20 and the journal surface 16.

[0007] A conventional bushing used in a bearing in a rolling mill is shown in FIG3(A) at 300. The bushing has an inner end 301 and an outer end 302, and includes: (a) an inner surface 304 formed into a cylindrical shape having a bushing length L B and the inner diameter ID, where the portion of the bushing length that produces the oil film is designated as the hydrodynamic length L H , (b) an outer surface 303 formed into a cylindrical shape, which includes an outer diameter OD.

[0008] Embodiments of the present invention are improvements over prior art systems and methods. Summary of the invention

[0009] In one embodiment, FIG. 3(B) Option 1, the present invention provides a bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing (300) comprising: (a) an inner surface (304) formed into a cylindrical shape, having a bushing length L B , hydrodynamic length L H and an inner diameter ID, and (b) an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the second portion includes: (i) an undercut portion (312) having an undercut radius r, the undercut portion being positioned adjacent to an end of the first portion adjacent to the inner end; (ii) a ramp portion (308) positioned adjacent to the undercut portion (312), the ramp portion (308) being provided with a tapered portion from the undercut portion (312) having a radius r to the inner end (301), the tapered portion tapering by an amount δmm, and wherein the ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing rated load {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0010] In another embodiment, option 2 of FIG. 3(B), the present invention provides a bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing comprising: (a) an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID, and (b) an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the second portion includes an undercut portion (312) having an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δmm, and wherein the second portion undercut by a quantitative amount δmm allows the bushing to deflect as the load increases at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0011] In another embodiment, FIG. 3(C) Option 1, the present invention provides a bearing comprising a bushing (300) for use in a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing (300) comprising: (a) an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L Hand an inner diameter ID, and (b) an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the second portion includes a ramp portion (308) positioned adjacent to the first portion, the ramp portion (308) providing a tapered portion from the first portion to the inner end (301), the tapered portion tapering by an amount δmm, and wherein the ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δmm, wherein δmm is defined as (bearing rated load {F in metric tons} / hydrodynamic length {L in mm H})*a, where a is selected in the range of 0.02≤a≤0.04, and the value of l is defined as b*hydrodynamic length {L H}, where b is selected in the range of 20%≤b≤35%. In one embodiment, δ mm is defined as (bearing load rating {F in metric tons} / fluid dynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0012] In another embodiment, option 2 of FIG. 3(C), the present invention provides a bearing comprising a bushing (300) for use in a rolling mill, the bushing having an inner end (301) and an outer end (302), the bushing (300) comprising: (a) an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID, and (b) an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l(310) of length, characterized in that the full length l(310) of the second portion is undercut by a quantitative amount δmm, wherein the second portion allows the bushing to deflect with increasing load at a maximum radial deflection of δmm, wherein δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, where a is selected in the range of 0.02≤a≤0.04, and where the value of l is defined as b*hydrodynamic length {L H}, where b is selected in the range of 20%≤b≤35%. In one embodiment, δ mm is defined as (bearing load rating {F in metric tons} / fluid dynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0013] In another embodiment, FIG. 3(B) Option 1, the present invention provides a method for reducing temperature accumulation on the inner side of a bushing (300), the bushing (300) being used in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the method comprising: (a) providing an inner surface (304) formed into a cylindrical shape having a bushing length L B , inner diameter ID and hydrodynamic length L H ; and (b) providing an outer surface (303) comprising: (1) a first portion of a length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, the second portion comprising: (i) an undercut portion (312) having an undercut radius r, the undercut portion being positioned adjacent to an end of the first portion adjacent to the inner end; (ii) a ramp portion (308) being positioned adjacent to the undercut portion (312), characterized in that the ramp portion (308) is provided with a tapered portion from the undercut portion (312) having a radius r to the inner end (301), the tapered portion tapering by an amount δmm, and wherein the ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0014] In another embodiment, option 2 of FIG. 3(B), the present invention provides a method for reducing temperature accumulation on the inner side of a bushing (300), the bushing (300) being used in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the method comprising: (a) providing an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; and (b) providing an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the second portion includes an undercut portion (312) having an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δmm, and wherein the second portion undercut by a quantitative amount δmm allows the bushing to deflect as the load increases at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0015] In another embodiment, FIG. 3(C) Option 1, the present invention provides a method for reducing temperature accumulation on the inner side of a bushing (300), the bushing (300) being used in a bearing of a rolling mill, the bushing having an inner end (301) and an outer end (302), the method comprising: (a) providing an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; (b) an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B-l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the second portion includes a ramp portion (308) positioned adjacent to the first portion, the ramp portion (308) providing a tapered portion from the first portion to the inner end (301), the tapered portion tapering by an amount δmm, and wherein the ramp portion (308) allows the bushing to deflect as the load increases at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0016] In another embodiment, FIG. 3(C) Option 2, the present invention provides a method for reducing temperature buildup on the inner side of a bushing (300), the bushing (300) being used in a bearing of a rolling mill, the bushing (300) having an inner end and an outer end, the method comprising: (a) providing an inner surface (304) formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and inner diameter ID; (b) providing an outer surface (303) having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l (310) of length, characterized in that the entire length l of the second portion is undercut by a quantitative amount δmm, wherein the second portion allows the bushing to deflect with increasing load at a maximum radial deflection of δmm. In one embodiment, δmm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] According to one or more various examples, the present disclosure is described in detail with reference to the attached drawings. The drawings are provided for the purpose of illustration only and only depict examples of the present disclosure. These drawings are provided to facilitate the reader's understanding of the present disclosure and should not be considered as limitations on the breadth, scope or applicability of the present disclosure. It should be noted that for clarity and convenience of illustration, these drawings are not necessarily to scale.

[0018] Figure 1(A)-Figure 1(B) A known fluid dynamic bearing assembly is depicted.

[0019] Figure 2 (A)- Figure 2 (C) Depicts the temperature distribution on the sleeve and bushing at the specified load / speed combination.

[0020] Figure 3(A)-Figure 3(C) A standard bushing is depicted, and then various embodiments of the present invention are presented depicting features added to the bushing. DETAILED DESCRIPTION

[0021] Although the present invention is shown and described in preferred embodiments, the present invention can be produced in many different configurations. Preferred embodiments of the present invention that are present in the drawings and will be described in detail herein, it should be understood that the present disclosure should be considered as an example of the principles of the present invention and associated functional illustrations for its construction, and is not intended to limit the present invention to the embodiments shown. Those skilled in the art will imagine many other possible variations within the scope of the present invention.

[0022] It should be noted that in this description, reference to "one embodiment" or "an embodiment" means that the features referred to are included in at least one embodiment of the present invention. In addition, separate references to "one embodiment" in this description do not necessarily refer to the same embodiment; however, these embodiments are not mutually exclusive unless otherwise specified and unless it is obvious to a person of ordinary skill in the art. Therefore, the present invention can include any changes in the combination and / or combination of the embodiments described herein.

[0023] Testing of bearings under various load and speed combinations has shown that the oil film thickness is thinner at the inner side of the bearing (the side closest to the roll face) than it is at the outer end. The difference is typically between 0.05 mm and 0.10 mm. Because the oil film is thinner on the inner end, the shear rate in the oil film is higher, and the bushing and sleeve temperatures also increase.

[0024] Figure 2 (A) to Figure 2(C) Graph showing temperature distribution in the sleeve and bushing at specified load / speed combinations, i.e., 50 RPM & 730 tons, 220 RPM & 650 tons, and 290 RPM & 510 tons, respectively. This data was obtained by testing using a full size 30"-75KL Morgoil fluid dynamic bearing. Thermocouples were mounted in the sleeve and bushing. The sleeve had five thermocouples mounted in an axis and as the sleeve rotated the signal was carried out through the slip ring. The fixed bushing had four axial rows of four thermocouples, two rows at + / - 10 degrees from bottom dead center and two rows at + / - 45 degrees from bottom dead center. In the graph, Figure 2 At the top of (C), the liner thermocouple locations are indicated by white asterisks and the sleeve thermocouple locations are indicated by black circles.

[0025] from Figure 2 (A) to Figure 2 (C) It can be seen that the temperature at the inside side of the bushing and sleeve is higher for all load / speed combinations, especially in the loaded area (+ / - 10 degrees in the bushing) where the film is at its minimum thickness.

[0026] Therefore, there is a need to dynamically adjust the film thickness on the inner end of the bearing, so as the load increases, it will be possible to reduce the temperature in that area. This is important because it can reduce the main category of bearing failure known as internal edge scraping.

[0027] The prior art is replete with examples of attempts to change the shape of a bearing (stationary member) to conform to the deformed shape of a shaft or housing. The present invention differs in that, in the no-load condition, the shape of the sleeve and bushing bearing surfaces does not change - in both cases it is cylindrical. Instead, the new concept is to add manufacturing features to the bushing to allow it to deflect as the load increases, but also to control the total deflection. For purposes of explanation, the expected maximum radial deflection will be calculated as (bearing rated load {F in metric tons} / hydrodynamic length {L in mm}) H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and the preferred a is 0.025.

[0028] The present invention provides a feature of length l on the outside diameter (OD) of the inner end of a bushing, such as that used in a rolling mill. A "hinge" feature exists to allow the inner end to deflect outwardly and the total deflection is set by the offset on the end, which is calculated as (bearing load rating {F in tonnes} / hydrodynamic length {L in mm) H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and the preferred a is 0.025.

[0029] FIG3(B) depicts an embodiment of the present invention. In one embodiment, FIG3(B) Option 1, the present invention discloses a bushing 300 for use in a bearing in a rolling mill, the bushing having an inner end 301 and an outer end 302, the bushing comprising: (a) an inner surface 304 formed into a cylindrical shape, having a bushing length L B , hydrodynamic length L H and inner diameter ID; (b) an outer surface 303, which includes an outer diameter OD: (1) a first portion of the length (L B -l), the first portion is cylindrically formed and has a first portion 303 (which is part of the initial outer surface 303); and (2) a second portion l of the length, the second portion comprising: (i) an undercut portion 312 located adjacent to the end of the first portion, adjacent to the inner end, where r (undercut radius) is preferably defined as 5% of l (310, the second portion of the length), but can alternatively be in the range of 2% to 10%; (ii) a second ramp portion 308 located adjacent to the undercut portion, wherein the second ramp portion allows the bushing to deflect as the load increases at the maximum radial deflection of δ. Where l is preferably defined as 25%*L H (hydrodynamic length), but can alternatively be in the range of 20% to 35%. In addition, the value for δ can preferably be calculated as (bearing load rating {F in tonnes} / hydrodynamic length {L in mm H})*a, where a is selected in the range of 0.02≤a≤0.04, preferably a is 0.025. Alternatively, in option 2 of FIG. 3(B), instead of the tapered portion from the hinge 312 to the inner end, the full length l is undercut by a quantitative δ mm, which is calculated in the same manner as option 1.

[0030] In another embodiment, option 1 of FIG. 3(C), the present invention discloses a bushing 300 for use in a bearing in a rolling mill, the bushing having an inner end 301 and an outer end 302, the bushing comprising: (a) an inner surface 304 formed into a cylindrical shape having a length L B and inner diameter ID; (b) an outer surface 303 having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -1), the first portion is cylindrically shaped and has a first portion 303; and (2) a second portion l of the length, the second portion including a ramp portion 308, which is located adjacent to the first ramp portion 303, wherein the second ramp portion allows the bushing to deflect as the load increases at the maximum radial deflection of δ. Alternatively, in FIG. 3(C) Option 2, instead of the taper on the second ramp portion 308, the full length l is undercut by a quantitative δ mm, which is calculated in the same manner as Option 1 above.

[0031] The bearing surface itself is cylindrical and deflects under load. That deflection is controllable by manipulating the stiffness of the deflection characteristic. The length l is the hydrodynamic bearing length L H function.

[0032] In one embodiment, FIG. 3(B) Option 1, the present invention provides a bushing for use in a bearing in a rolling mill, the bushing having an inner end and an outer end, the bushing comprising: (a) an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID, and (b) an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion is conically shaped and has a first portion; and (2) a second portion of length l, the second portion comprising: (i) an undercut portion having an undercut radius r, the undercut portion being positioned adjacent to an end of the first portion and adjacent to the inner end; (ii) a ramp portion being positioned adjacent to the undercut portion, and wherein the ramp portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0033] In another embodiment, option 2 of FIG. 3(B), the present invention provides a bushing for use in a bearing in a rolling mill, the bushing having an inner end and an outer end, the bushing comprising: (a) an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; and (b) an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, wherein the second portion includes an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0034] In another embodiment, FIG. 3(C) Option 1, the present invention provides a bushing for use in a bearing in a rolling mill, the bushing having an inner end and an outer end, the bushing comprising: (a) an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; (b) an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, the second portion including a ramp portion positioned adjacent to the first portion, wherein the second ramp portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0035] In another embodiment, FIG. 3(C) Option 2, the present invention provides a bushing for use in a bearing in a rolling mill, the bushing having an inner end and an outer end, the bushing comprising: (a) an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; (b) an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, wherein the full length l of the second portion is undercut by a quantitative amount δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0036] In another embodiment, FIG. 3(B) Option 1, the present invention provides a method for reducing temperature buildup on the inner side of a bushing, the bushing being used in a bearing of a rolling mill, the bushing having an inner end and an outer end, the method comprising: (a) providing an inner surface formed into a cylindrical shape having a bushing length L B , inner diameter ID and hydrodynamic length L H ; and (b) providing an outer surface comprising: (1) a first portion (L B -l), the first portion being cylindrically shaped; and (2) a second portion of length l, the second portion comprising: (i) an undercut portion having an undercut radius r, the undercut portion being positioned adjacent to an end of the first portion adjacent to the inner end; and (ii) a ramp portion being positioned adjacent to the undercut portion, and wherein the ramp portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0037] In another embodiment, FIG. 3(B) Option 2, the present invention provides a method for reducing temperature buildup on the inner side of a bushing, the bushing being used in a bearing of a rolling mill, the bushing having an inner end and an outer end, the method comprising: (a) providing an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L H and an inner diameter ID; and (b) providing an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B-l), the first portion being cylindrically shaped; and (2) a second portion l of length, wherein the second portion includes an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l. In the same embodiment, the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%, preferably c is 5%.

[0038] In another embodiment, FIG. 3(C) Option 1, the present invention provides a method for reducing temperature buildup on the inner side of a bushing for use in a bearing of a rolling mill, the bushing having an inner end and an outer end, the method comprising: (a) forming a cylindrical inner surface having a bushing length L B , hydrodynamic length L H and an inner diameter ID; (b) an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, the second portion including a ramp portion positioned adjacent to the first portion, wherein the second ramp portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0039] In another embodiment, FIG. 3(C) Option 2, the present invention provides a method for reducing temperature buildup on the inner side of a bushing for use in a bearing of a rolling mill, the bushing having an inner end and an outer end, the method comprising: (a) providing an inner surface formed into a cylindrical shape having a bushing length L B , hydrodynamic length L Hand an inner diameter ID; (b) providing an outer surface having an outer diameter OD, the outer surface comprising: (1) a first portion of the length (L B -l), the first portion being cylindrically shaped; and (2) a second portion l of length, wherein the full length l of the second portion is undercut by a quantitative amount δ. In one embodiment, δ is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H})*a, wherein a is selected in the range of 0.02≤a≤0.04, and preferably a is 0.025. In the same embodiment, the value of l is defined as b*hydrodynamic length {L H}, wherein b is selected in the range of 20%≤b≤35%, and preferably b is 25%. In the same embodiment, the length (L B -l)>length l.

[0040] in conclusion

[0041] Systems and methods have been shown in the above embodiments for effective implementation of bearing temperature reduction through bushing modification. While various preferred embodiments have been illustrated and described, it should be understood that it is not intended to limit the invention by this disclosure, but on the contrary, it is intended to cover all modifications that fall within the spirit and scope of the invention as defined in the appended claims.

Claims

1. A bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing (300) comprising: a) An inner surface (304) formed into a cylindrical shape, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; as well as b) an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) the second part of the length l(310), Characterized in that the second part comprises: i) an undercut portion (312) having an undercut radius r, the undercut portion being located adjacent an end of the first portion, the end of the first portion being adjacent the inner end; ii) a ramp portion (308) located adjacent to the undercut portion (312), the ramp portion (308) being provided with a tapered portion from the undercut portion (312) having a radius r to the inner end (301), the tapered portion tapering by an amount δ mm, and The ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δ mm.

2. The bushing (300) of claim 1, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H })*a, where a is selected in the range of 0.02≤a≤0.

04.

3. The bushing (300) of claim 2, wherein a is 0.

025.

4. The bushing (300) according to claim 2, wherein the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

5. The bushing (300) of claim 4, wherein b is 25%.

6. The bushing (300) according to claim 1, wherein the undercut radius r is defined as c*length l, wherein c is selected in the range of 2%≤c≤10%.

7. The bushing (300) according to claim 6, wherein c is 5%.

8. The bushing (300) according to claim 1, wherein the length (L B -l)>length l.

9. The bushing (300) according to claim 1, wherein a sleeve is arranged to surround the inner surface of the bushing (300), wherein a gap exists between the bushing (300) and the outer surface of the sleeve, and the gap is configured to maintain a fluid-dynamically maintained oil film.

10. The bushing (300) according to claim 9, wherein the bushing (300) is fixed in a bearing seat.

11. The bushing (300) of claim 10, wherein an end plate and a cover are provided at the outer end (302) to seal the bushing (300) and the sleeve.

12. A bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing comprising: a) An inner surface (304) formed into a cylindrical shape, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; as well as b) an outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) the second part of the length l(310), The second portion comprises an undercut portion (312) having an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δ mm, and The second portion, which is undercut by a certain amount of δ mm, allows the bushing to deflect as the load increases at a maximum radial deflection of δ mm.

13. The bushing (300) of claim 12, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm H })*a, where a is selected in the range of 0.02≤a≤0.

04.

14. The bushing (300) of claim 13, wherein a is 0.

025.

15. The bushing (300) according to claim 13, wherein the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

16. The bushing (300) of claim 15, wherein b is 25%.

17. The bushing (300) according to claim 12, wherein the undercut radius r is defined as c*length l, wherein c is selected in the range of 2% ≤ c ≤ 10%.

18. The bushing (300) of claim 17, wherein c is 5%.

19. The bushing (300) of claim 12, wherein the length (L B -l)>length l.

20. A bearing comprising a bushing (300) for use in a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the bushing (300) comprising: a) An inner surface (304) formed into a cylindrical shape, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; b) an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) the second part of the length l(310), Characterized in that the second portion comprises a ramp portion (308) located adjacent to the first portion, the ramp portion (308) being provided with a tapered portion from the first portion to the inner end (301), the tapered portion tapering by an amount δ mm, and wherein the ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δ mm, where δmm is defined as (bearing load rating {F in tonnes} / hydrodynamic length {L in mm H })*a, where a is selected in the range of 0.02≤a≤0.04, and the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

21. The bearing of claim 20, wherein a is 0.

025.

22. The bearing of claim 21, wherein b is 25%.

23. The bearing according to claim 20, wherein the length (L B -l)>length l.

24. A bearing comprising a bushing (300) for use in a rolling mill, the bushing having an inner end (301) and an outer end (302), the bushing (300) comprising: a) An inner surface (304) formed into a cylindrical shape, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; b) an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) the second part of the length l(310), characterised in that the complete length l (310) of the second portion is undercut by a quantitative amount δ mm; wherein the second portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ mm, where δmm is defined as (bearing load rating {F in tonnes} / hydrodynamic length {L in mm H })*a, where a is selected in the range of 0.02≤a≤0.04, and where the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

25. The bearing of claim 24, wherein a is 0.

025.

26. The bearing of claim 24, wherein b is 25%.

27. The bearing according to claim 24, wherein the length (L B -l)>length l.

28. A method for reducing temperature build-up on the inner side of a bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the method comprising: a) Providing an inner surface (304) shaped as a cylinder, the inner surface (304) having a bushing length L B , inner diameter ID and hydrodynamic length L H ; as well as b) providing an outer surface (303), said outer surface (303) comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) a second portion 1 (310) of length, the second portion comprising: i) an undercut portion (312) having an undercut radius r, the undercut portion being located adjacent an end of the first portion, the end of the first portion being adjacent the inner end; ii) a ramp portion (308) located adjacent to the undercut portion (312), characterized in that the ramp portion (308) is provided with a tapered portion from the undercut portion (312) having a radius r to the inner end (301), the tapered portion tapering by an amount δ mm, and The ramp portion (308) allows the bushing (300) to deflect as the load increases at a maximum radial deflection of δ mm.

29. The method of claim 28, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm} H })*a, where a is selected in the range of 0.02≤a≤0.04, and the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

30. The method of claim 28, wherein the length (L B -l)>length l.

31. The method of claim 28, wherein a is 0.

025.

32. The method of claim 28, wherein b is 25%.

33. The method of claim 28, wherein the undercut radius r is defined as c*length l, wherein c is selected in the range of 2% ≤ c ≤ 10%.

34. The method of claim 28, wherein c is 5%.

35. A method for reducing temperature build-up on the inner side of a bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an inner end (301) and an outer end (302), the method comprising: a) Providing an inner surface (304) shaped as a cylinder, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; as well as b) providing an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) a second portion l (310) of length, characterized in that the second portion comprises an undercut portion (312), the undercut portion (312) having an undercut radius r, wherein the full length l of the second portion is undercut by a quantitative amount δ mm, and The second portion, which is undercut by a certain amount of δ mm, allows the bushing to deflect as the load increases at a maximum radial deflection of δ mm.

36. The method of claim 35, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm}) H })*a, where a is selected in the range of 0.02≤a≤0.04, and where the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

37. The method of claim 36, wherein a is 0.

025.

38. The method of claim 36, wherein b is 25%.

39. The method of claim 36, wherein the undercut radius r is defined as c*length l, wherein c is selected in the range of 2% ≤ c ≤ 10%.

40. The method of claim 39, wherein c is 5%.

41. The method of claim 36, wherein the length (L B -l)>length l.

42. A method for reducing temperature build-up on the inner side of a bushing (300) for use in a bearing of a rolling mill, the bushing having an inner end (301) and an outer end (302), the method comprising: a) Providing an inner surface (304) shaped as a cylinder, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; b) an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) a second portion l (310) of length, characterized in that the second portion includes a ramp portion (308), the ramp portion (308) being positioned adjacent to the first portion, the ramp portion (308) being provided with a tapered portion from the first portion to the inner end (301), the tapered portion tapering by an amount δmm, and wherein the ramp portion (308) allows the bushing to deflect as the load increases at a maximum radial deflection of δmm.

43. The method of claim 42, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm}) H })*a, where a is selected in the range of 0.02≤a≤0.04, and the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

44. The method of claim 43, wherein a is 0.

025.

45. The method of claim 43, wherein b is 25%.

46. ​​The method of claim 42, wherein the length (L B -l)>length l.

47. A method for reducing temperature buildup on the interior side of a bushing (300) for use in a bearing of a rolling mill, the bushing (300) having an interior end and an exterior end, the method comprising: a) Providing an inner surface (304) shaped as a cylinder, the inner surface (304) having a bushing length L B , hydrodynamic length L H and inner diameter ID; b) providing an outer surface (303), the outer surface (303) having an outer diameter OD, the outer surface comprising: 1) The first part of the length (L B -1), the first portion is cylindrically shaped; and 2) A second portion l (310) of length, characterised in that the full length l of the second portion is undercut by a quantitative δ mm, wherein the second portion allows the bushing to deflect as the load increases at a maximum radial deflection of δ mm.

48. The method of claim 47, wherein δ mm is defined as (bearing load rating {F in metric tons} / hydrodynamic length {L in mm}) H })*a, where a is selected in the range of 0.02≤a≤0.04, and the value of l is defined as b*hydrodynamic length {L H }, where b is selected in the range of 20%≤b≤35%.

49. The method of claim 48, wherein a is 0.

025.

50. The method of claim 48, wherein b is 25%.

51. The method of claim 47, wherein the length (L B -l)>length l.

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