JP2008215416A - Rolling bearing for steel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensively producible rolling bearing for steel, stably usable over a long period even in an environment where it is kept in contact with a large quantity of water. <P>SOLUTION: This rolling bearing 1 for the steel incorporated into a backup roller of a scale breaker, is composed of a bearing body 1a incorporated between an outer cylinder 3 of the backup roller 2 and a fixed shaft 4 inserted into the outer cylinder 3 and rotatably supporting the outer cylinder 3, and a sealing device 1b incorporated outside of the body 1a. The bearing body 1a is an automatic aligning roller bearing of arranging barreled rollers 7 of two rows between an inner ring 5 having tracks of two rows and an outer ring 6 having a track of a spherical surface, Its inside space is filled with a porous solid lubricant being a solid material made porous by foaming and hardening a resin component with a lubrication component and the resin component as an essential component. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a steel rolling bearing used in an environment in contact with a large amount of water.

  Examples of steel rolling bearings used in harsh environments in contact with a large amount of water include scale breaker backup roll bearings used in a pretreatment process in a pickling line for hot-rolled steel strip. The scale breaker is a work roll reinforced by a backup roll that gives the strip steel several percent elongation (bending) and causes cracks in the scale layer (oxide film) formed on the surface of the strip steel during the cooling process after hot rolling. At the same time, the scale is removed by spraying high-pressure water on the surface of the steel strip. Usually, a large amount of water is also applied to the bearing portion of the backup roll that reinforces the work roll.

  In general, rolling bearings for steel used in such applications are equipped with a sealing device with an excellent sealing property such as an oil seal in order to prevent water from entering the inside of the bearing filled with a lubricant. ing. Moreover, it replaces with the sealing device which has an oil seal, and the sealing device of the composite seal structure incorporating the oil seal and the labyrinth seal is known (refer patent document 1). However, in steel rolling bearings that come into contact with a large amount of water, if an oil seal with a high sealing performance is used in the sealing structure of the sealing device, the lip portion of the oil seal hardens due to frictional heat when sliding against the mating member. Therefore, it is inevitable that the sealing performance deteriorates during use.

  In particular, when a foreign material with high hardness such as a scale falls on a large amount of water in addition to a large amount of water, such as a backup roll bearing of a work roll installed in a scale breaker, the foreign material is a sliding surface between the lip portion and the mating member. Between them, the lip portion is damaged such as abnormal wear or tearing, or the mating member is worn, so that the sealing performance is deteriorated at an early stage. For this reason, as a countermeasure against intrusion of water and foreign matter, the oil seal and the mating member are frequently replaced, and the problem is that the maintenance cost is high.

  As a countermeasure to this problem, there is known a bearing that is filled with a solid lubricant inside the bearing and combined with a labyrinth seal in order to maintain a good lubricating state even when water enters the bearing (see Patent Document 2). ). This bearing uses a solid lubricant that does not emulsify even when it comes into contact with moisture as a lubricant to be filled inside the bearing. This prevents leakage to the outside of the bearing. In the case of a bearing in which a solid lubricant is sealed, a labyrinth seal can be employed because it is not always required to have high sealing performance. In Patent Document 2, a solid lubricant is used in which lubricating grease is dispersed and held in ultrahigh molecular weight polyethylene as a synthetic resin base material.

However, since the solid lubricant in Patent Document 2 is in the form of grease in the state before firing, there are many manufacturing processes such as a step of heating and cooling once to cure while retaining the grease, It is difficult to meet the demand for cost reduction. In addition, although firing is currently performed in a heating furnace, there is a problem that the size of the bearing that can be filled with the solid lubricant is limited by the size of the heating furnace.
In addition, depending on the specifications for filling the bearing, the solid lubricant contracts during the cooling process after solidifying in the bearing, and the lubricant itself entraps the rolling elements, which tends to increase the rotational torque and generate heat. There is a problem that it is easy.
Japanese Utility Model Publication No. 5-20891 JP 2005-172039 A

  The present invention has been made to cope with such a problem, and an object thereof is to provide a rolling bearing for steel that can be used stably for a long period of time even in an environment in contact with a large amount of water and can be produced at low cost. And

The rolling bearing for steel according to the present invention is a rolling bearing that is used in an environment in contact with a large amount of water and includes a sealing device for preventing water from entering the inside of the bearing filled with a porous solid lubricant. The porous solid lubricant is characterized in that it is a solid material in which a lubricating component and a resin component are essential components, and the resin component is made porous by foaming and curing. In particular, the resin component is a polyurethane resin.
The sealing structure of the sealing device is a labyrinth seal structure.

The rolling bearing for steel of the present invention is used for supporting a backup roll of a scale breaker.
The bearing type is any of a self-aligning roller bearing, a cylindrical roller bearing, a needle bearing, and a deep groove ball bearing.

In the rolling bearing for steel of the present invention, a porous solid lubricant is sealed inside the bearing (the space between the cage and the inner and outer rings, the space between the inner and outer rings in the rolling bearing without the cage), and the bearing. A sealing device is provided to prevent water from entering the interior. As the lubricant filled in the bearing, a porous solid lubricant that does not emulsify even when it comes into contact with moisture is used. There is no leakage to the outside of the bearing, and the lubrication state inside the bearing can be maintained well.
Therefore, the bearing life when used in an environment in contact with a large amount of water, such as when used to support a backup roll of a scale breaker, can be greatly extended compared to the conventional case. Therefore, a device incorporating this bearing has a longer maintenance cycle, an improved operating rate, and a reduced running cost.

  This porous solid lubricant is a solid material in which a lubricating component and a resin component are essential components, and the resin component is foamed and cured to make it porous, and the lubricating component is occluded in the foamed and cured solid component. The For this reason, in the rolling bearing for steel of the present invention, the retained amount of the lubricating component in the porous solid lubricant is larger than the retained amount due to the simple impregnation in the pores, and moreover than in the porous solid lubricant during operation. Since the lubricating component is gradually released around the moving body or the like, it can contribute to the extension of the service life. In the present invention, “occlusion” means that a liquid / semi-solid lubricating component does not react with other compounding components and is contained in a solid resin without becoming a compound.

  In addition, this porous solid lubricant requires much less energy when bent compared to a non-foamed material, and can be flexibly deformed while retaining the lubricating component at a high density. Therefore, in the process of solidifying the porous solid lubricant and cooling it, even if the solid lubricant contracts and embraces the rolling elements, it can be easily deformed because the energy required for bending and deformation is small. The problem of increased rotational torque can be prevented.

In the rolling bearing for steel of the present invention, a porous solid lubricant filled as a lubricant that fills the bearing space also serves as a seal member, and therefore, a labyrinth seal with a simple structure may be employed as the sealing device. it can. By adopting the labyrinth seal, the problem of heat generation and wear of the oil seal lip portion in the conventional structure can be eliminated, and the structure of the device incorporating the bearing can be simplified.
In addition, the porous solid lubricant used in the present invention only foams and hardens a mixture containing a lubricating component and a resin component as essential components. You may make it harden | cure and shape | mold, and you may post-process in the target shape by the grinding etc. which were cut | cured after solidifying with a normal pressure. Therefore, no special equipment is required, and the size and shape of the bearing to be filled are not limited.
As a result, production efficiency can be improved and manufacturing costs can be reduced.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a state in which a rolling bearing 1 for steel of the embodiment is incorporated in a backup roll 2 that reinforces a work roll (not shown) of a scale breaker used in a pretreatment process of a hot-rolled steel pickling line. Show. This bearing 1 is incorporated between an outer cylinder 3 of a backup roll 2 and a fixed shaft 4 inserted into the outer cylinder 3, and rotatably supports the outer cylinder 3. A bearing body 1a, And a sealing device 1b incorporated outside 1a.
The bearing 1 used to support the scale breaker backup roll usually has an outer diameter of about 130 mm.

  The bearing body 1a is an open type self-aligning roller bearing in which two rows of barrel-shaped rollers 7 are arranged between an inner ring 5 having two rows of raceways and an outer ring 6 having a spherical raceway. The space is filled with a porous solid lubricant with almost no gap. The resin component, the lubricating component, the filling method, and the like constituting the porous solid lubricant will be described later.

  On the other hand, the sealing device 1b is composed of an outer member 8 fitted to the inner periphery of the outer cylinder 3 end portion and an inner member 9 fitted to the outer periphery of the fixed shaft 4 end portion. The labyrinth seal structure is formed by each unevenness of the outer peripheral surface of the member 9 facing each other with a slight gap. Further, the outer member 8 and the inner member 9 are prevented from coming off by retaining rings 10 and 11 fitted in the annular grooves of the outer cylinder 3 and the fixed shaft 4, respectively, and one end portion is the inner and outer rings 5 and 6 of the bearing body 1a. The bearing body 1a is restrained from moving in the axial direction.

  The present invention is not limited to the scale breaker backup roll bearing described in the embodiment, and can be widely applied to various types of steel rolling bearings used in an environment in contact with a large amount of water. Examples include deep groove ball bearings, angular contact ball bearings, thrust ball bearings, cylindrical roller bearings, needle roller bearings, thrust cylindrical roller bearings, thrust needle roller bearings, tapered roller bearings, thrust tapered roller bearings, self-aligning ball bearings, Examples thereof include a self-aligning roller bearing, a thrust self-aligning roller bearing, and a plain bearing. Further, these bearings can be applied regardless of the presence or absence of a seal member or a shield plate.

The rolling bearing for steel according to the present invention occludes a lubricating component in the resin of the encapsulated porous solid lubricant, so that the lubricant is caused by the flexibility of the resin, for example, thermal expansion due to rotation of a backup roll or heat reception, or capillary action. Can be released from between the resin molecules to the outside. At this time, the amount of the lubricating oil or the like that oozes out can be minimized by changing the degree of elastic deformation according to the magnitude of the external force or the like by selecting the resin. Moreover, the density of the porous solid lubricant can be changed by controlling the blending amount of the blending components of the mixture.
Further, in the porous solid lubricant used in the present invention, the resin component has a large surface area due to foaming, and it is possible to temporarily hold excess lubricating oil or the like that has oozed out in the foam bubbles again. The amount of the lubricating oil or the like that oozes out is stable, and the amount of the lubricating oil or the like that is retained is larger than the non-foamed state by occluding the lubricant in the resin and impregnating the bubbles.

As the resin component constituting the porous solid lubricant used in the present invention, a resin component having rubber-like elasticity after foaming and curing, and having a leaching property of the lubricant component by deformation is preferable.
Foaming / curing may be in a form in which foaming / curing is performed at the time of resin production, or in a form in which a foaming agent is added to the resin component and foaming / curing is performed in molding. Here, curing means a cross-linking reaction and / or a phenomenon in which a liquid is solidified. The rubber-like elasticity means rubber elasticity and means that deformation applied by an external force returns to the original shape by eliminating the external force.

As the resin component, either an elastomer or a plastomer or both of a resin (plastic) or rubber can be used as an alloy or copolymer component.
In the case of rubber, various rubbers such as natural rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, silicone rubber, urethane elastomer, fluorine rubber, and chlorosulfone rubber can be employed.
In the case of plastics, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacetal resin, polyamide 4,6 resin (PA4,6), polyamide 6,6 resin (PA6,6), polyamide General-purpose plastics and engineering plastics such as 6T resin (PA6T) and polyamide 9T resin (PA9T) can be used.
Without being limited to the above plastics, urethane foams such as soft urethane foam, rigid urethane foam, and semi-rigid urethane foam can also be used.
Among the resin components, a polyurethane resin that is easily foamed and cured to make it porous is preferable.

  The polyurethane resin that can be used in the present invention is a foamed / cured product obtained by a reaction between an isocyanate and a polyol, and is preferably a foamed / cured product of a urethane prepolymer having an isocyanate group (—NCO) in the molecule. This isocyanate group may be blocked by other substituents. The isocyanate group contained in the molecule may be at the end of the molecular chain or may be contained at the end of the side chain branched from the molecular chain. The urethane prepolymer may have a urethane bond in the molecular chain. The curing agent for the urethane prepolymer may be a polyol or a polyamine.

The urethane prepolymer can be obtained by reacting a compound having an active hydrogen group with a polyisocyanate.
Examples of the compound having an active hydrogen group include low molecular polyols, polyether polyols, polyester polyols, and castor oil polyols. These can be used alone or as a mixture of two or more. Examples of the low molecular polyol include divalent ones such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, etc. (3- to 8-valent ones) For example, glycerin, trimethylolpropane, hexanetriol, pentaerythritol, sorbitol, shoelace and the like.

  Examples of the polyether polyol include alkylene oxide (alkylene oxide having 2 to 4 carbon atoms, for example, ethylene oxide, propylene oxide, butylene oxide) adducts of the above low molecular polyols and ring-opening polymers of alkylene oxides. Includes polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol.

Examples of polyester polyols include polyester polyols, polycaprolactone polyols, and polyether ester polyols. Polyester polyols are carboxylic acids (aliphatic saturated or unsaturated carboxylic acids such as adipic acid, azelaic acid, dodecanoic acid, maleic acid, fumaric acid, itaconic acid, dimerized linoleic acid and / or aromatic carboxylic acids such as phthalic acid. , Isophthalic acid) and a polyol (the above low molecular polyol and / or polyether polyol).
Polycaprolactone polyol is a polymerization initiator for glycols and triols such as ε-caprolactone, α-methyl-ε-caprolactone, ε-methyl-ε-caprolactone, etc. as organometallic compounds, metal chelate compounds, fatty acid metal acylates, etc. Obtained by addition polymerization in the presence of a catalyst. The polyether ester polyol can be obtained by addition reaction of a polyester having a carboxyl group and / or a hydroxyl group at the terminal with an alkylene oxide such as ethylene oxide or propylene oxide. As the castor oil-based polyol, castor oil and castor oil or castor oil fatty acid and the above low molecular polyol, polyether polyol, and polyester polyol are transesterified or esterified polyol.

Polyisocyanates include aromatic diisocyanates, aliphatic or alicyclic and polyisocyanate compounds.
Aromatic diisocyanates include, for example, diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate Is mentioned.
Aliphatic or alicyclic diisocyanates include, for example, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 1,3-cyclobutane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isopropane diisocyanate. 2,4-hexahydrotoluylene diisocyanate, 2,6-hexahydrotoluylene diisocyanate, 1,3-hexahydrophenyl diisocyanate, 1,4-hexahydrophenyl diisocyanate, 2,4′perhydrodiphenylmethane diisocyanate, 4, 4'-perhydrodiphenylmethane diisocyanate is mentioned.
Examples of the polyisocyanate compound include 4,4 ′, 4 ″ -triphenylmethane triisocyanate, 4,6,4′-diphenyl triisocyanate, 2,4,4′-diphenyl ether triisocyanate, and polymethylene polyphenyl polyisocyanate. In addition, those obtained by modifying a part of these isocyanates into biuret, allophanate, carbodiimide, oxazolidone, amide, imide and the like can be mentioned.

Examples of the urethane prepolymer suitable for the present invention include polypolymer ester polyol and prepolymer obtained by addition polymerization of polyisocyanate to polyether polyol, which are known as casting urethane prepolymers.
The polylactone ester polyol is preferably a urethane prepolymer obtained by addition polymerization of a polyisocyanate in the presence of a short-chain polyol to a polylactone ester polyol obtained by ring-opening reaction of caprolactone.
Examples of the polyether polyol include alkylene oxide addition products or ring-opening polymerization products, and urethane prepolymers obtained by addition polymerization of these with polyisocyanates are preferable.

  If the commercial item of the urethane prepolymer which can be used conveniently for this invention is illustrated, the brand name Plaxel EP by Daicel Chemical Industries may be mentioned. Plaxel EP is a white solid urethane prepolymer having a melting point above room temperature. As an example of polyether polyol, trade name Preminol manufactured by Asahi Glass Co., Ltd. may be mentioned. Preminol is a polyether polyol having a molecular weight of 5000-12000.

  Curing agents for curing the urethane prepolymer and the like include 3,3′-dichloro-4,4′-diaminodiphenylmethane (hereinafter referred to as MOCA) and 4,4′-diamino-3,3′-diethyl-5. , 5'-dimethyldiphenylmethane, trimethylene-bis- (4-aminobenzoate), bis (methylthio) -2,4-toluenediamine, bis (methylthio) -2,6-toluenediamine, methylthiotoluenediamine, 3,5 -Diethyltoluene-2,4-diamine, aromatic polyamines typified by 3,5-diethyltoluene-2,6-diamine, the above polyisocyanates, low molecules typified by 1,4-butaneglycol and trimethylolpropane Polyol, polyether polyol, castor oil-based polyol, polyester-based polyol, hydroxyl-terminated liquid polybutadiene Hydroxyl-terminated liquid polyisoprene, hydroxyl-terminated polyolefin-based polyols and liquid rubbers having two or more hydroxyl groups represented by compounds in which the terminal hydroxyl groups of these compounds are modified with isocyanate groups or epoxy groups, etc. are used alone or in combination. Can be used. Of these, aromatic polyamines are preferred for curing urethane prepolymers obtained by addition polymerization of polylactone ester polyols and polyisocyanates because of their superiority in cost and physical properties.

  As a means for foaming the resin component, a well-known foaming means may be employed. For example, a chemical foaming method that generates a volatile gas by a chemical reaction, an organic solvent having a relatively low boiling point such as water, acetone, hexane, or the like. Heat treatment such as physical methods for heating and vaporization, mechanical foaming method in which an inert gas such as nitrogen or air is blown from the outside, azobisisobutyronitrile (AIBN), azodicarbonamide (ADCA), etc. Examples include a method of using a decomposable foaming agent that is chemically decomposed by light irradiation to generate nitrogen gas or the like.

  Since the urethane prepolymer used in the present invention has an isocyanate group in the molecule, it is preferable to use a chemical foaming method using carbon dioxide generated by a chemical reaction between the isocyanate group and the water molecule using water as a foaming agent. This method is preferable because open cells are easily generated.

Moreover, when using the chemical foaming method with such a reaction, it is preferable to use a catalyst as needed, for example, a tertiary amine catalyst or an organometallic catalyst is used. Examples of the tertiary amine catalyst include monoamines, diamines, triamines, cyclic amines, alcohol amines, ether amines, imidazole derivatives, and acid block amine catalysts.
Examples of organometallic catalysts include stanaoctate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin maleate, dioctyltin dimercaptide, dioctyltin thiocarboxylate, octenoate, etc. Is mentioned. Moreover, you may mix and use these multiple types for the purpose of adjusting the balance of reaction.

  Without being limited to the above resin components, various adhesives such as urethane adhesives, cyanoacrylate adhesives, epoxy adhesives, polyvinyl acetate adhesives, polyimide adhesives can be used by foaming and curing. .

  In the present invention, various additives can be used in the resin component as necessary. Additives include antioxidants typified by hindered phenols, reinforcing agents (carbon black, white carbon, colloidal silica, etc.), inorganic fillers (calcium carbonate, barium sulfate, talc, clay, meteorite powder, etc.) Examples include anti-aging agents, flame retardants, metal deactivators, antistatic agents, antifungal agents, fillers, and coloring agents.

The lubricating component that can be used in the present invention can be used regardless of the type as long as it does not dissolve the solid component forming the foam. As the lubricating component, for example, lubricating oil, grease, wax and the like can be used alone or in combination.
Examples of the lubricating oil include paraffinic and naphthenic mineral oils, ester synthetic oils, ether synthetic oils, hydrocarbon synthetic oils, GTL base oils, fluorine oils, and silicone oils. These can be used alone or as a mixed oil.
If the resin material and lubricating oil do not dissolve or disperse due to chemical compatibility such as polarity, using a lubricating oil with close viscosity makes it easier to physically mix and prevent segregation of the lubricating oil. It becomes.

  The grease is obtained by adding a thickener to a base oil, and examples of the base oil include the above-described lubricating oil. Thickeners include, but are not limited to, soaps such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap, aluminum complex soap, and urea-based compounds such as diurea compounds and polyurea compounds. It is not a thing.

The diurea compound is obtained, for example, by reaction of diisocyanate and monoamine. Diisocyanates include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, and monoamines include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, Examples include p-toluidine, cyclohexylamine and the like.
The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those used for the production of diurea compounds. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, and the like. Is mentioned.

  Examples of waxes include hydrocarbon synthetic waxes, polyethylene waxes, fatty acid ester waxes, fatty acid amide waxes, ketones / amines, hydrogenated oils, and the like. Oils may be mixed with these waxes, and the same oil components as those described above can be used as the oil component to be used.

  Lubricating components further include solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, oily agents such as amines, fatty acids and oils, antioxidants such as amines and phenols, petroleum sulfonates, Rust inhibitors such as dinonyl naphthalene sulfonate, sorbitan ester, extreme pressure agents such as sulfur and sulfur-phosphorus, antiwear agents such as organic zinc and phosphorus, metal deactivators such as benzotriazole and sodium nitrite Various additives such as viscosity index improvers such as polymethacrylate and polystyrene may be included.

  The blending ratio of the base oil in the grease is 1 to 98% by weight, preferably 5 to 95% by weight, based on the whole grease component. If the base oil is less than 1% by weight, it will be difficult to sufficiently supply the lubricating oil to the necessary locations. On the other hand, when it is more than 98% by weight, it does not solidify even at low temperatures and remains liquid.

The porous solid lubricant used in the present invention is obtained by foaming and curing a mixture in which a lubricating component and a resin component are essential components, and a curing agent or a foaming agent is blended therewith.
The blending ratio of the lubricating component is 1 to 90% by weight, preferably 5 to 80% by weight, based on the entire mixture. If the lubrication component is less than 1% by weight, the supply amount of the lubrication component is small and a sufficient life cannot be obtained, or the friction coefficient increases due to lack of lubricant, which causes wear. When it exceeds 90% by weight, it does not solidify.
The blending ratio of the resin is 8 to 98% by weight, preferably 20 to 80% by weight, based on the entire mixture. When it is less than 8% by weight, it does not solidify, and when it is more than 98% by weight, the supply amount of the lubricating component is small and a sufficient life cannot be obtained.

  The blending ratio of the curing agent is determined depending on the blending ratio of the resin and the foaming ratio, and the blending ratio of the foaming agent is determined in relation to the foaming ratio described later.

The method of mixing the mixture is not particularly limited, and for example, the mixture can be mixed using a generally used stirrer such as a Henschel mixer, a ribbon mixer, a juicer mixer, a mixing head, or the like.
It is desirable that the above mixture use a surfactant such as a commercially available silicone-based foam stabilizer to uniformly disperse each raw material molecule. Further, the surface tension can be controlled by the type of the foam stabilizer, and the type of the generated bubbles can be controlled to open cells or closed cells. Examples of such surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, and fluorine surfactants.

The porous solid lubricant used in the present invention has a lubricating component occluded inside the resin, and can supply the lubricating component to the outside by thermal expansion due to rotation of the backup roll or heat reception, or capillary action. .
In order to occlude the lubricating component inside the resin, it is desirable to employ a reactive impregnation method in which a foaming reaction and a curing reaction are simultaneously performed in the presence of the lubricating component. In this way, it is possible to highly fill the inside of the resin with the lubricant, and thereafter, the post-impregnation step of impregnating and replenishing the lubricant can be omitted.
On the other hand, a foam solid body is molded in advance, and only a post-impregnation method impregnating this with a lubricant does not allow a sufficient amount of liquid lubricant to penetrate into the resin. If the lubricating oil is released in a short time and used for a long time, the lubricating oil may be insufficiently supplied. For this reason, the post-impregnation step is preferably employed as an auxiliary means for the reactive impregnation method.

In the rolling bearing for steel of the present invention, the porous solid lubricant may be foamed and cured after pouring a mixture containing a lubricating component and a resin component as essential components into the bearing, or foamed and cured at normal pressure. Later, it can be post-processed into a desired shape by cutting or grinding, and incorporated into the bearing.
It is possible to easily fill any part in a bearing having a complicated shape, and there is no need for a molding die or a grinding process for obtaining a foamed molded product. -It is preferable to adopt a method of pouring into the bearing before curing and foaming and curing in the bearing. By adopting this method, the manufacturing process is simplified and the cost can be reduced.

  It is preferable that the bubbles to be generated when foamed by foaming at the time of foaming / curing are open cells that communicate with each other, and the lubricating component can be directly removed from the surface of the resin via the open cells by external stress. This is to supply. In the case of closed cells where the bubbles do not communicate with each other, the entire amount of lubricating oil in the solid component is temporarily isolated in the closed cells, making it difficult to move between the bubbles and supplying them around the rolling elements when necessary. May not be.

  In the present invention, the open cell ratio of the porous solid lubricant is preferably 50% or more, more preferably 70% or more. When the open cell ratio is less than 50%, the ratio of the lubricating oil in the resin component temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary.

  The expansion ratio of the porous solid lubricant used in the present invention is preferably 1.1 to 100 times. More preferably, it is 1.1 to 10 times. This is because when the expansion ratio is less than 1.1 times, the bubble volume is small and deformation is not allowed when external stress is applied, or the porous solid is too hard to deform following external stress. There is. If it exceeds 100 times, it will be difficult to obtain the strength to withstand external stress, which may lead to damage or destruction.

Specific examples of the porous solid lubricant used in the present invention are illustrated below.
[Specific Example 1]
Urethane prepolymer (manufactured by Daicel Chemical Industries: Plaxel EP1130) 55% by weight, silicone foam stabilizer (Toray Industries, Inc .: SRX298) 2% by weight and urea grease (manufactured by Nippon Oil Co., Ltd .: Vironock Universal N6C) 37% by weight And stirred well at 120 ° C. To this was added 4% by weight of an amine curing agent (manufactured by Ihara Chemical Co., Ltd .: Iharacamine MT), and after stirring, 2% by weight of ion-exchanged water as a blowing agent was added to obtain a mixture. This mixture was filled in the internal space of a ball bearing 6204 (inner diameter 20 mm) and then allowed to harden for 1 hour in a thermostatic bath set at 120 ° C. to obtain a bearing filled with a porous solid lubricant.

[Specific Example 2]
Polyether polyol (Asahi Glass Co., Ltd .: Preminol SX4004) 20% by weight, silicone foam stabilizer (Toray Industries, Inc .: SRX298) 0.5% by weight, lubricating oil (Shin Nippon Oil Co., Ltd .: Turbine 100) 70% by weight, amine type A catalyst (Tosoh Corporation: TOYOCAT DB2) 0.5% by weight and 0.5% by weight of water as a blowing agent were added, and the mixture was heated at 90 ° C. and well stirred. To this, 8.5% by weight of isocyanate (manufactured by Nippon Polyurethane Co., Ltd .: Coronate T80) was added and stirred well to obtain a mixture. This mixture was filled in the internal space of a ball bearing 6204 (inner diameter 20 mm) and then allowed to harden for 1 hour in a thermostatic bath set at 120 ° C. to obtain a bearing filled with a porous solid lubricant.

  The rolling bearing for steel of the present invention is excellent in the lubrication performance of a solid lubricant that holds lubricating oil, can be used stably for a long time even in an environment where it contacts with a large amount of water, and can be produced at low cost. It can be suitably used as a rolling bearing for steel, such as a backup roll bearing of a scale breaker used in a pretreatment process in a steel pickling line.

It is a front sectional view of the rolling bearing for steel of an embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rolling bearing for steel 1a Bearing main body 1b Sealing device 2 Backup roll 3 Outer cylinder 4 Fixed shaft 5 Inner ring 6 Outer ring 7 Roller 8 Outer member 8
9 Inner member 9
10 Retaining ring 11 Retaining ring

Claims (5)

A rolling bearing that is used in an environment where a large amount of water comes into contact with a sealing device for preventing water from entering a bearing filled with a porous solid lubricant.
The rolling solid bearing for steel, wherein the porous solid lubricant is a solid material in which a lubricating component and a resin component are essential components, and the resin component is foamed and cured to be porous.   The rolling bearing for steel according to claim 1, wherein the resin component is a polyurethane resin.   The rolling bearing for steel according to claim 1 or 2, wherein the seal structure of the sealing device is a labyrinth seal structure.   The said rolling bearing for steel is used for support of the backup roll of a scale breaker, The rolling bearing for steel of Claim 1, 2 or 3 characterized by the above-mentioned.   5. The steel rolling bearing according to claim 1, wherein the bearing type is any of a self-aligning roller bearing, a cylindrical roller bearing, a needle bearing, and a deep groove ball bearing. A rolling bearing for steel according to one item.

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