WO2022065308A1

WO2022065308A1 - Backup roll unit for tension leveler

Info

Publication number: WO2022065308A1
Application number: PCT/JP2021/034595
Authority: WO
Inventors: 隆司八木; 琢也小津
Original assignee: Ntn株式会社
Priority date: 2020-09-25
Filing date: 2021-09-21
Publication date: 2022-03-31
Also published as: TW202214364A; JP2022053851A

Abstract

Provided is a backup roll unit that suppresses increases in rotational torque and leakage of lubricant in a structure in which a solid lubricant is sealed in a ball bearing supporting a backup roll. The backup roll unit 1 is for a tension leveler in which a ball bearing 2 rotatably supporting a roll 4 with respect to a shaft 3 is arranged between the roll 4 and the shaft 3. The ball bearing 2 has an inner race 5 and an outer race 6 which are bearing rings, a plurality of balls 8 interposed between the inner race 5 and the outer race 6, and a holder 7 for holding the balls 8. A solid lubricant 9 is sealed in the bearing interior space of the ball bearing 2, and the total volume of the solid lubricant 9 is 30-40% of the volume of the bearing interior space.

Description

Backup roll unit for tension leveler

The present invention relates to a backup roll unit that supports a work roll or an intermediate roll in a tension leveler device. In particular, the present invention relates to a backup roll unit that employs ball bearings to support the backup roll.

At the final stage of the process of rolling a metal material in a steel material manufacturing facility, a tension leveler device is used to correct the shape defects (warp and waviness) of the metal plate and metal strip. This tension leveler device may be used alone or as part of another device.

FIG. 4 shows an example of the tension leveler device. FIG. 4 is a schematic diagram of equipment for correcting a shape defect of a metal plate at the final stage of the rolling process. As shown in FIG. 4, the roll unit 23 is vertically arranged with respect to the metal plate 22 being processed, and the metal plate 22 is passed between the work rolls 24 of the upper and lower roll units 23 to apply a tensile force. Roll while rolling. The upper and lower roll units 23 apply a compressive force in the metal direction to the metal plate 22. The work roll 24 and the intermediate roll 25 rotate with the movement of the metal plate 22, and the backup roll 26 receives a load in the radial direction. The work roll 24 reinforced by the backup roll 26 gives the metal plate 22 a few percent elongation. Further, in the tension leveler device 21, a plurality of deflector rolls 27 that support the metal plate 22 and change the direction are arranged. The deflector roll 27 has a load sensor incorporated therein and is also used as a shape meter roll for detecting distortion.

The specifications of the backup roll differ depending on the size of the radial load and the required torque according to the type of metal plate material and usage conditions. When the radial load is large, a backup roll unit equipped with a roller bearing that supports the radial load and a ball bearing that supports the axial load is used in order to have a configuration having a high load-bearing capacity. For example, in the backup roll unit of Patent Document 1, two needle bearings are provided along the axial direction in the middle of the axial direction of the roll for radial load as bearings that rotatably support the roll with respect to the shaft. Ball bearings are provided on the outside at one end of the roll in the axial direction for thrust load.

On the other hand, when the radial load is small and low torque is required, a backup roll unit that supports the backup roll only with ball bearings is used. This backup roll unit is provided with deep groove ball bearings on both sides in the axial direction along the axial direction between the shaft and the roll. In this unit, this pair of deep groove ball bearings receives a radial load and a thrust load, and a separate needle bearing (roller bearing) or the like is not provided for the radial load. By using only deep groove ball bearings and reducing the torque, slip between rolls can be suppressed even when the frictional force with the work roll or intermediate roll is small.

In addition, in the above process using the tension leveler device, a cleaning liquid is continuously sprayed to cool the rolled metal plate and remove dust adhering to the metal plate, and a large amount of cleaning liquid is also applied to the backup roll that reinforces the work roll. It takes. Such a backup roll is provided with a sealing structure for preventing the cleaning liquid from entering the bearing in order to prevent the lubricant inside the bearing from flowing out due to the cleaning liquid.

Japanese Unexamined Patent Publication No. 2013-146479

As described above, in the configuration where deep groove ball bearings support radial load and axial load without having roller bearings inside, slip between rolls is possible even when the frictional force with the work roll or intermediate roll is small due to the low torque. Can be suppressed, and the occurrence of distortion and the like can be suppressed. However, for example, when the object to be stretched is a metal plate or a metal band made of a material having a lower stretching strength and a lower surface hardness than steel, such as aluminum, distortion, wrinkles, and chatter marks (fine striped patterns) are likely to occur. Therefore, it is desirable to be able to achieve more stable low torque even in the configuration of only deep groove ball bearings.

In addition, if the grease of the lubricant leaks from the unit and adheres to the material to be stretched, it may cause distortion, wrinkles, and chatter marks, and may lead to torque increase and early damage of the deep groove ball bearing due to lack of lubricating oil.

The present invention has been made in view of such circumstances, and provides a backup roll unit that suppresses an increase in rotational torque and leakage of lubricant in a configuration in which a solid lubricant is sealed in a ball bearing that supports a backup roll. The purpose is to do.

The backup roll unit for tension leveler of the present invention is a backup roll unit for tension leveler in which a ball bearing that rotatably supports the roll with respect to the shaft is arranged between the roll and the shaft. Has an inner ring and an outer ring which are raceway rings, a plurality of balls interposed between the inner ring and the outer ring, and a cage for holding these balls, and a solid lubricant is provided in the bearing internal space of the ball bearing. Is enclosed, and the total volume of the solid lubricant is 30% to 40% of the volume of the bearing internal space. In particular, it is characterized by not having a roller bearing inside the unit.

The cage is a corrugated cage in which a pair of annular bodies are connected by a connecting portion located between pockets for holding the balls, and the solid lubricant is a solid lubricant between the balls of the cage. It is characterized in that it is fixed to the connecting portion.

The solid lubricant is characterized by being a solidified body of a mixture of a resin component and a lubricating component. Further, the resin component is an ultra-high molecular weight polyolefin, and the lubricating component is a grease containing a base oil and a thickener.

The ball bearing has a sealing plate fixed to one of the inner ring and the outer ring, and the sealing plate has a gap between the inner ring and the other bearing ring.

The backup roll unit for tension leveler of the present invention is a unit in which a ball bearing is arranged between a roll and a shaft, and a solid lubricant is sealed in the bearing internal space of the ball bearing, and the total volume of the solid lubricant is the bearing. Since it is 30% to 40% of the volume of the internal space, it is possible to suppress an increase in sliding resistance due to the solid lubricant and suppress an increase in torque. That is, by setting the total volume of the solid lubricant to 40% or less, the solid lubricant can be arranged between the balls, and the sliding area with the inner ring, the outer ring, and the sealing plate can be reduced. In addition, by setting it to 30% or more, the solid lubricant can be fixed by winding it around a cage while ensuring the absolute amount of the lubricating component contained in the solid lubricant, and the movement in the bearing is suppressed and rolling. Entrainment on the surface can be suppressed.

In addition, the structure of the cage is a corrugated cage in which a pair of annular bodies are connected by a connecting portion located between the pockets that hold the balls, and solid lubricant is wound around the connecting portion of the cage between the balls. By fixing the solid lubricant in the cage, the solid lubricant can be held in the cage connecting portion between the balls, and the entrainment in the rolling surface can be suppressed.

Further, by using the solid lubricant as a solidified body of a mixture of the resin component and the lubricating component, the solid lubricant can be steadily fixed to the cage. For example, a semi-solid lubricant (a mixture of a resin component and a lubricating component) that is semi-solid at room temperature is wound around a cage, molded, and then thermally solidified to be a solid lubricant even when exposed to cleaning liquids, coolants, and dew condensation. A configuration that does not easily fall off or flow out can be obtained.

Further, in the ball bearing, a sealing plate fixed to one of the inner ring and the outer ring is provided, and the sealing plate has a gap between the bearing and the other bearing ring, so that the torque due to the sealing device can be obtained. It is possible to suppress the rise, heat generation of the bearing, and temperature rise, and to suppress early damage due to deterioration of the solid lubricant.

As a result of these, the present invention can provide a backup roll unit having a long life without impairing the low torque performance of the ball bearing. In particular, it can be suitably used for a unit having a structure in which a ball bearing supports a radial load and an axial load without having a roller bearing (needle-shaped roller bearing) inside, which requires a small radial load and a low torque.

It is a perspective view which shows an example of the backup roll unit of this invention. It is an enlarged view of the ball bearing part in FIG. It is a front view of the ball bearing part in FIG. It is a schematic diagram of a tension leveler device.

The tension leveler device to which the backup roll unit of the present invention is applied is a known tension leveler device described with reference to FIG. 4 and the like. This device is used in steel material manufacturing equipment to correct shape defects (warpage and waviness) of metal plates and metal strips, and is used in the final step of rolling or after rolling. This device can be used alone or incorporated into equipment such as coating equipment and shear equipment.

As shown in FIG. 4, in the tension leveler device 21, the metal plate 22 is stretched by the work roll 24 reinforced by the backup roll 26. The backup roll unit for a tension leveler of the present invention is a unit composed of a backup roll, a shaft of the roll, and a ball bearing interposed between the shaft and the roll. This backup roll unit is used in an environment where it comes into contact with a large amount of liquid such as a cleaning liquid in the equipment.

An embodiment of the backup roll unit for tension leveler of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view of the backup roll unit, and shows some components with the front half removed. 2 is an enlarged view of one end of the roll of FIG. 1, and FIG. 3 is a front view of FIG. 2.
As shown in FIG. 1, the backup roll unit 1 has a structure in which a ball bearing 2 that rotatably supports the roll 4 with respect to the shaft 3 is arranged between the roll 4 and the shaft 3. The ball bearings 2 are provided at both ends of the roll 4 in the axial direction, and are used as a pair. In the present invention, the "axial direction" is the direction along the axial center of the shaft 3, and the "diametrical direction" is the radial direction centered on the axial center of the shaft 3. As the material of the roll 4 and the shaft 3, various steel materials can be used. For example, bearing steel is used for the roll 4 and carbon steel is used for the shaft 3.

The backup roll unit 1 of the form shown in FIGS. 1 to 3 does not have a roller bearing (needle-shaped roller bearing) inside, and supports the radial load and the axial load applied to the roll 4 in the ball bearing 2. There is. Therefore, the torque is lower than that of a unit provided with a roller bearing (needle roller bearing) inside, the radial load is small, and it can be suitably used for applications requiring low torque.

The shaft 3 is a stepped shaft body, and has a shaft main body portion formed in an axial intermediate portion and shaft end portions provided at both ends in the axial direction. The shaft end of the shaft 3 protrudes from the roll 4. Further, the shaft 3 is inserted by providing a radial gap inside the roll 4. The pair of ball bearings 2 are arranged between the shaft main body portion of the shaft 3 and each shaft end portion.

The roll 4 has a cylindrical shape, and ball bearings 2 are arranged at both ends in the axial direction thereof. Further, for the purpose of preventing foreign matter (water or the like) from entering the inside of the roll 4, a cover 11 is provided on the outside of the ball bearings 2 at both ends in the axial direction of the roll 4. The cover 11 is fixed to the shaft 3.

As shown in FIGS. 2 and 3, the ball bearing 2 is a deep groove ball bearing, and the inner ring 5 and the outer ring 6 which are raceway rings are arranged concentrically, and a plurality of ball bearings 2 are arranged between the inner ring rolling surface and the outer ring rolling surface. The balls 8 are arranged. The cage 7 has pockets 7a for holding the balls 8 at a plurality of positions at equal intervals in the circumferential direction, and the pockets 7a hold the balls 8 at equal intervals in the circumferential direction. As the material of the inner ring 5, the outer ring 6 and the ball 8, any material generally used as a bearing material can be used, and for example, bearing steel, carbon steel, stainless steel, high-speed steel and the like can be used. Further, as the ball bearing 2, in addition to a deep groove ball bearing, an angular contact ball bearing, a four-point contact type ball bearing, or the like can be applied.

The cage 7 is a corrugated cage in which a pair of annular bodies are connected by a connecting portion 7b located between the pockets 7a. The annular body constituting the cage 7 has a plurality of curved portions curved along the ball 8 and flat plate portions connecting these curved portions alternately in the circumferential direction. The pair of annular bodies are fixed and integrated with rivets or the like in the flat plate portions in a state where the curved portions and the flat plate portions face each other. The portion where the flat plate portions overlap is the connecting portion 7b. Each annular body is manufactured by press-molding a metal plate. As the metal plate, any material generally used as a cage material can be used, and for example, cold rolled steel plate, carbon steel and the like can be used.

The ball bearing 2 has a sealing plate 10 at both ends in the axial direction of the inner and outer rings. The sealing plate 10 is composed of a disk-shaped core metal 10a made of a cold-rolled steel plate or the like, and a rubber portion 10b fixed to the core metal 10a and made of nitrile rubber or the like. The outer peripheral portion of the sealing plate 10 is fixed to the groove on the inner circumference of the outer ring 6, and the inner peripheral portion forms a labyrinth gap (non-contact seal) with the groove on the outer circumference of the inner ring 5. By providing the sealing plate 10, it is possible to prevent the cleaning liquid or the like that has entered beyond the cover 11 from directly entering the inside of the bearing, and it is possible to suppress deterioration and outflow of the solid lubricant. Further, since the solid lubricant is used, it is possible to suppress the outflow of the lubricating component while keeping the rotational torque low by providing a labyrinth gap in the sealing plate 10.

Further, the configuration of the sealing plate 10 is not limited to this, and for example, a metal shield (without a rubber portion) can be adopted. Further, it may be mounted only on one end of the ball bearing 2, particularly only on the end face side of the roll 4. In addition, the fixing to the raceway ring may be on the inner ring side.

In the ball bearing 2, the solid lubricant 9 is sealed in the inner space of the bearing. The present invention is characterized in that the solid lubricant 9 is encapsulated so that its total volume is 30% to 40% of the volume of the bearing internal space. Here, the "volume of the bearing internal space" refers to the ball 8 and the cage 7 in the space closed by the inner ring 5, the outer ring 6, and the sealing plate 10 (up to the bearing end face when the sealing plate is on one side). The volume of the space to be excluded. Further, the "total volume of the solid lubricant" is the total volume of the solid lubricant in the bearing internal space, and in the case of a mode (spot) in which the solid lubricant is separated and sealed in a plurality of places, those are used. The total volume.

If the total volume of the solid lubricant is less than 30%, the amount of the lubricating component gradually released from the solid lubricant to the periphery of the rolling element may be insufficient, and the increase in rotational torque (particularly the starting torque) may not be sufficiently suppressed. There is a risk of separation from the cage and a shortage of lubricating components during long-term operation. Further, if the total volume of the solid lubricant exceeds 40%, the sliding area with the inner ring, the outer ring, and the sealing plate tends to increase, and the solid lubricant tends to be caught in the rolling surface, which may increase or fluctuate the rotational torque. be.

In the backup roll unit for tension leveler of the present invention, the cleaning liquid or the like may flow into the bearing, and at that time, the cleaning liquid or the like comes into contact with the solid lubricant. By setting the total volume of the solid lubricant to 30% or more, the solid lubricant can be fixed by wrapping it around a cage, and the movement or separation of the solid lubricant can be suppressed. Further, while ensuring the absolute amount of the lubricating component contained in the solid lubricant, it is possible to prevent the lubricating component from becoming insufficient in the long-term operation of the backup roll unit. In addition, by setting the total volume of the solid lubricant to 40% or less, it is possible to suppress the increase or fluctuation of the rotational torque as described above, and the metal plate or metal strip to be rolled has a higher draw strength than steel such as aluminum. Even if the material has a low surface hardness and a low surface hardness, it is possible to suppress the occurrence of distortion, wrinkles, and chatter marks.

The solid lubricant used in the present invention will be described. The type of the solid lubricant used in the present invention is not particularly limited, and for example, (1) a solidified body of a mixture of a resin component (including one that reacts to become a resin component) and a lubricating component, and (2) solidification. Examples thereof include a resin component impregnated with a lubricating component. It is preferable to use the solid lubricant of (1) because it can retain a large amount of lubricating components and can be closely fixed to a cage or the like. Details of the solid lubricant will be described below.

As the resin component of the solid lubricant, general-purpose plastics such as ultra-high molecular weight polyolefin, polyamide, polyacetal, fluororesin, silicone, polyurethane, polyolefin, polystyrene, and polyvinyl chloride, and engineering plastics can be used. These are powdered and mixed with a lubricating component to form a mixture, which is solidified by heat or the like to form a solidified body.

Specific examples of the ultra-high molecular weight polyolefin include a powder composed of polyethylene, polypropylene, polybutene or a copolymer thereof, or a mixed powder containing individual powders thereof. Here, the average molecular weight of each powder measured by the viscosity method is preferably 1 × 10 ⁶ to 3 × 10 ⁶ . Polyolefins in such a molecular weight range are superior to low molecular weight polyolefins in terms of rigidity and oil retention. Further, among the ultra-high molecular weight polyolefins, it is preferable to use ultra-high molecular weight polyethylene.

Specific examples of the polyamide include polyamide 11, polyamide 12, polyamide 46, polyamide 6, polyamide 6-6, polyamide 6-10, polyamide 6-12, and polyamide MXD6. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) and the like.

Lubricating oil or grease can be used as the lubricating component of the solid lubricant.
The lubricating oil is not particularly limited, and paraffin-based or naphthen-based mineral oil, ester-based synthetic oil, ether-based synthetic oil, hydrocarbon-based synthetic oil, fluorine oil, silicone oil, animal oil, vegetable oil and the like can be used. These can be used alone or as a mixed oil. If the resin component and the lubricating oil do not dissolve or disperse due to chemical compatibility such as polarity, using a lubricating oil with a similar viscosity makes it easier to physically mix and prevents segregation of the lubricating oil. Will be.

Specific examples of mineral oil include liquid paraffin oil, spindle oil, turbine oil, machine oil, dynamo oil, and highly refined oil. Specific examples of the ester-based synthetic oil include diester oils such as dibutyl sebacate, di-2-ethylhexyl sebacate, and dioctyl adipate, and aromatic ester oils such as trioctyl remeritate and tridecyl trimellitate. Specific examples of the ether-based synthetic oil include alkyl diphenyl ether oils such as monoalkyl diphenyl ether oils, dialkyl diphenyl ether oils, and polyalkyl diphenyl ether oils. Specific examples of the hydrocarbon-based synthetic oil include 1-octene, 1-nonene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene and 1-octadecene. , 1-Nonadecene, 1-Eicosen, 1-Dodecene, 1-Tetradodecene and other oligomers of polyα-olefin oil (PAO oil). Specific examples of the fluorine oil include perfluoropolyether oil and low polymers of chlorotrifluoroethylene. Examples of animal oils include sanagi oil, neatsfoot oil, lard (pork fat), sardine oil, herring oil and the like. Examples of vegetable oils include camellia oil, olive oil, peanut oil, castor oil, and rapeseed oil.

Grease is a base oil with a thickener added, and the above-mentioned lubricating oil can be used as the base oil. Specific examples of the thickener include soaps such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap, and aluminum complex soap, and urea compounds such as diurea compounds and polyurea compounds.

The diurea compound can be obtained, for example, by reacting diisocyanate with a monoamine. Examples of the diisocyanate include phenylenediocyanate, diphenyldiisocyanate, phenyldiisocyanate, diphenylmethanediisocyanate, octadecanediisocyanate, decanediisocyanate, hexanediisocyanate and the like. Examples thereof include p-toluidine and cyclohexylamine. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or a diamine. Examples of diisocyanates and monoamines include those used for producing diurea compounds, and examples of diamines include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, and xylenediamine. Can be mentioned.

Lubricating components include solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, oily agents such as amines, fatty acids and fats and oils, antioxidants such as amines and phenols, and petroleum sulfonates. Rust preventives such as dinonylnaphthalene sulphonate and sorbitan ester, extreme pressure agents such as sulfur-based and sulfur-lin-based, anti-wear agents such as organic zinc and phosphorus-based, metal inactivating agents such as benzotriazole and sodium nitrite. , Polymethacrylate, and various additives such as viscosity index improvers such as polystyrene may be contained.

In addition, solid wax may be added to the solid lubricant for the purpose of suppressing oil seepage and preventing leakage of the lubricating component from the bearing during firing. Examples of the solid wax include vegetable waxes such as carnauba wax and candelina wax, animal waxes such as beeswax and insect white wax, and petroleum waxes such as paraffin wax. The solid wax may be a compound such as a small molecule polyolefin containing the same.

Among these resin components and lubricating components, the following solid lubricants A to E can be exemplified as specific combinations and encapsulation methods.

[Solid Lubricant A]
As the solid lubricant A, ultra-high molecular weight polyethylene powder is used as a resin component, and grease in which lithium soap is dispersed in mineral oil is used as a lubricating component. This grease and the ultra-high molecular weight polyethylene powder are uniformly mixed. This fluid mixture is filled and sealed between the balls of the bearing so as to be wound around the connecting part of the cage, etc., and heated and fired to a temperature (melting temperature) above the gel point of the ultra-high molecular weight polyolefin. After that, it is cooled and solidified to obtain a solid lubricant A. The mixing method is not particularly limited, and a general stirrer such as a Henschel mixer or a ribbon mixer can be used. Further, it is preferable that the heating and firing conditions are the above-mentioned gel point or higher and the grease drop point or lower. For example, when the average molecular weight of ultra-high molecular weight polyethylene is 1 × 10 ⁶ to 3 × 10 ⁶ , it is preferable to heat it at a temperature of 150 to 200 ° C. The content of the ultra-high molecular weight polyethylene powder in the solid lubricant A is, for example, 20 to 50% by mass with respect to the entire solid lubricant.

[Solid lubricant B]
As the solid lubricant B, an ultra-high molecular weight polyolefin powder is used as a resin component, and one or more oils selected from liquid paraffin, PAO oil, vegetable oil and animal oil are used as a lubricating component. Alternatively, as a lubricating component, a grease based on one or more oils selected from liquid paraffin, PAO oil, vegetable oil and animal oil is used. The encapsulation method and the like are the same as those of the solid lubricant A. The content of the ultra-high molecular weight polyolefin powder in the solid lubricant B is, for example, 1 to 95% by mass with respect to the entire solid lubricant.

[Solid lubricant C]
As the solid lubricant C, a combination of a modified silicone oil and a curing agent is used as a resin component, and a lubricating oil incompatible with silicone or a grease based on the lubricating oil is used as a lubricating component. Examples of the curing agent include bisphenol type epoxy compounds and cyclic aliphatic epoxy compounds. By polymerizing the modified silicone oil and the curing agent in the lubricating component, the structure is such that the lubricating component is retained by the three-dimensional network structure of silicone. The encapsulation method is the same as that of the solid lubricant A, and a uniform mixture of modified silicone oil, a curing agent, and a lubricating component is filled and encapsulated between the balls of the bearing at the position of the connecting portion of the cage, etc. It is heated and fired at a temperature to be cured to obtain a solid lubricant C having the above structure. The content of the resin component (modified silicone oil and curing agent) in the solid lubricant C is, for example, 20 to 80% by mass with respect to the entire solid lubricant.

[Solid lubricant D]
As the solid lubricant D, polyamide powder or polyacetal powder is used as the resin component, and one or more oils selected from liquid paraffin, PAO oil, vegetable oil and animal oil are used as the lubricating component. Alternatively, as a lubricating component, a grease based on one or more oils selected from liquid paraffin, PAO oil, vegetable oil and animal oil is used. The encapsulation method and the like are the same as those of the solid lubricant A. The content of the resin component in the solid lubricant D is, for example, 1 to 95% by mass with respect to the entire solid lubricant.

[Solid Lubricant E]
The solid lubricant E uses an ultra-high molecular weight polyolefin powder as a resin component, a grease based on paraffin mineral oil or the like as a lubricating component, and further contains a solid wax. This solid wax is a wax containing a normal paraffin component having 36 or more linear carbon atoms in a total of 13% by weight or more with respect to the entire solid wax. In particular, the normal paraffin component preferably has the mode of the content in the linear carbon atom number distribution between 30 and 33. The encapsulation method and the like are the same as those of the solid lubricant A. The content of the ultra-high molecular weight polyolefin powder in the solid lubricant E is, for example, 10 to 30% by mass with respect to the total solid lubricant. The content of the solid wax is, for example, 1 to 10% by mass with respect to the entire solid lubricant.

As an example of other solid lubricants, it is obtained by reacting a polyol and diisocyanate in the presence of a lubricating component, or a urethane prepolymer having an isocyanate group in the molecule and a curing agent are reacted in the presence of a lubricating component. Examples thereof include the obtained polyurethane-based solid lubricant and the foamed solid lubricant.

The above solid lubricant is filled with a mixture of the resin component and the lubricating component before solidification (solid lubricant material) and solidified inside the bearing. That is, it is a solidified body of a mixture of a resin component (including one that reacts to become a resin component) and a lubricating component. Since the resin component is solidified in the presence of the lubricating component, a large amount of the lubricating component can be retained, and the lubricating component (base oil in the grease) is gradually released during operation, so that the lubricating performance can be maintained for a long period of time. In addition, the lubricating component does not easily flow out even if it comes into contact with a cleaning liquid or the like.

The filling / filling position of the solid lubricant is not particularly limited, but it is preferable to fill / fill the solid lubricant so as to be wound around the connecting portion of the corrugated cage. Specifically, a grease-like mixture that is fluid at room temperature before solidification is filled around the connecting portion (the portion where the flat plate portions are combined) so as to be connected above and below the flat plate portion in the radial direction. By solidifying this, it becomes a solid lubricant wrapped around the connecting portion. As a result, the solid lubricant is steadily fixed to the cage and does not easily fall off from the cage even when exposed to a cleaning liquid or high temperature. Further, in the present invention, since the amount of the solid lubricant enclosed is 30% to 40% of the volume of the bearing internal space as described above, the cage is connected between the balls (between the pockets) instead of the full pack. It is arranged so as to be scattered in the portion, and it is possible to suppress the entrainment on the rolling surface.

An evaluation test was conducted on the bearing alone and the backup roll unit for tension leveler using the bearing by changing the encapsulation volume of the solid lubricants of the following components A to C in various ways.

Ingredient A:
A grease containing mineral oil as a base oil and lithium soap as a thickener, which are lubricating components, and ultra-high molecular weight polyethylene powder, which is a resin component, were mixed in a predetermined blending ratio. The obtained mixture is filled between the balls of the rolling bearing (rolling bearing in FIG. 2) so as to be wound around the connecting portion of the cage, heated and fired at a predetermined temperature, and then cooled and solidified. A rolling bearing in which the solid lubricant of component A was sealed was used. The encapsulation amount was adjusted so that the total volume of the solid lubricant with respect to the volume of the bearing internal space would be the value in the table. As described above, the encapsulation portion is the connecting portion of the cage between the balls of the rolling bearing, and is adjusted so as to be substantially equal at each connecting portion. The size (volume) of the solid lubricant in one connecting portion differs depending on the encapsulation amount.

Ingredient B:
A grease containing PAO oil as a base oil and a urea compound as a thickener, which is a lubricating component, and ultra-high molecular weight polyethylene powder, which is a resin component, were mixed. The compounding ratio of the grease and the ultra-high molecular weight polyethylene is the same as that of the component A. The obtained mixture is filled between the balls of the rolling bearing (rolling bearing in FIG. 2) so as to be wound around the connecting portion of the cage, heated and fired at a predetermined temperature, and then cooled and solidified. A rolling bearing in which the solid lubricant of component B was sealed was used. The method for adjusting the encapsulation amount is the same as that for component A.

Ingredient C:
The modified silicone oil, the epoxy curing agent, and the grease were mixed. The grease is the same as the grease of component B. The compounding ratio of the resin component (modified silicone oil and epoxy curing agent) and the lubricating component (grease) is the same as that of component A. The obtained mixture is filled and sealed between the balls of the rolling bearing (rolling bearing in FIG. 2) at the position of the connecting portion of the cage, heated and fired at a predetermined temperature to cure, and the solid lubricant of component C is formed. Was used as a rolling bearing. The method for adjusting the encapsulation amount is the same as that for component A.

A torque test at start-up and a torque test at rotation were carried out for each rolling bearing unit. The results are shown in Table 1. In each torque test, the test bearing was fixed, and the torque generated at startup and the torque during rotation at a constant speed were measured under predetermined temperature and load conditions. The test conditions were the same for all encapsulation volumes.
The "large / small judgment" of the starting torque is set to "x" when the torque value exceeds the specified value, "○" is set when the torque value does not exceed the specified value, and the "tactile judgment" is when manually rotated. This is the evaluation of the examiner, and was evaluated as "x" when there was a feeling of being caught, and "○" when there was no feeling of being caught. Further, the "large / small judgment" of the torque during rotation is the same as the case of the torque at startup, and the "variation judgment" is "x" when the fluctuation range of the torque value at a predetermined time interval exceeds the specified value, and the predetermined time. When the fluctuation range of the torque value at the interval does not exceed the specified value, it is set as "○".

In addition, for each rolling bearing unit, the state of the solid lubricant was confirmed by visually observing the bearing after a predetermined time (after the test was completed) as a condition judgment after operation. The results are shown in Table 1. If there is any abnormality (the content of the abnormality is described in the table), it is marked with "x", and if there is no particular problem, it is marked with "○".

In addition, the rolling bearing in which the solid lubricant of component A was sealed was incorporated into the backup roll unit for tension leveler (units of FIGS. 1 to 3), and the starting torque and the appearance state were judged. The start-up torque test is the same as for a single bearing, and the appearance condition is determined by visually observing the bearing in the unit after a predetermined time has elapsed (after the test is completed) and confirming the presence or absence of oil. The results are shown in Table 2.

As shown in Tables 1 and 2, in a configuration in which a ball bearing supporting a backup roll is filled with a solid lubricant, the total volume of the solid lubricant is within a predetermined range (30% to 40% of the volume of the bearing internal space). By doing so, it was confirmed that the increase in rotational torque could be suppressed.

In addition, the unit of "30%" in Table 2 had a total volume of the solid lubricant of component A of 80%, and other than that, the torque during rotation was 1/5 of that of the same unit.

The backup roll unit of the present invention can be used for a tension leveler device. In particular, in a configuration in which a ball bearing that supports a backup roll is filled with a solid lubricant, an increase in rotational torque can be suppressed, so a roller bearing (needle-shaped roller bearing) is installed inside, which requires a small radial load and low torque. It can be suitably used for a backup roll unit in which a ball bearing supports a radial load and an axial load without a ball bearing.

1 Backup roll unit 2 Ball bearing 3 Shaft 4 Roll 5 Inner ring 6 Outer ring 7 Cage 8 Ball 9 Solid lubricant 10 Sealing plate 11 Cover 21 Tension leveler device 22 Metal plate 23 Roll unit 24 Work roll 25 Intermediate roll 26 Backup roll 27 Deflector roll

Claims

A backup roll unit for a tension leveler in which a ball bearing that rotatably supports the roll with respect to the shaft is arranged between the roll and the shaft.
The ball bearing has an inner ring and an outer ring which are raceway rings, a plurality of balls interposed between the inner ring and the outer ring, and a cage for holding these balls.
A backup roll unit for a tension leveler, characterized in that a solid lubricant is sealed in the bearing internal space of the ball bearing, and the total volume of the solid lubricant is 30% to 40% of the volume of the bearing internal space. ..
The cage is a corrugated cage in which a pair of annular bodies are joined by a connecting portion located between pockets holding the ball.
The backup roll unit for a tension leveler according to claim 1, wherein the solid lubricant is fixed between the balls to a connecting portion of the cage.
The backup roll unit for a tension leveler according to claim 1, wherein the solid lubricant is a solidified body of a mixture of a resin component and a lubricating component.
The backup roll unit for a tension leveler according to claim 3, wherein the resin component is an ultra-high molecular weight polyolefin, and the lubricating component is a grease containing a base oil and a thickener.
The ball bearing has a sealing plate fixed to one of the inner ring and the outer ring, and the sealing plate has a gap between the inner ring and the other bearing ring. The backup roll unit for the tension leveler described.
The backup roll unit for a tension leveler according to claim 1, wherein the unit does not have a roller bearing inside.