JP2008298120A - Bearing unit and roll for continuous casting equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit not deforming a seal due to a pressure of grease when both sides of a bearing are thermally expanded, and a roll for a continuous casting equipment. <P>SOLUTION: In this bearing unit 2, a bearing 3 with a seal is interposed between a shaft 1 and a bearing housing 4, and oil seals 14, 15 are provided on both sides of the bearing 3 with the seal. A space between the bearing housing 4, the shaft 1 and the oil seal 14 is filled with grease 11, and the bearing housing 4, the shaft 1, the oil seal 14, and the free end side oil seal 15 are communicated with each other by a bypass 16. The bypass 16 is formed by a groove formed on at least one of the inside diameter face of the bearing housing 4 and the outside diameter face of the bearing 3, and a space between the seal 8 with the bearing 3, the bearing housing 4 and the free end side oil seal 15 is filled with a foamed solid lubricant 18, whose essential components are a lubricating component and a resin component and which is formed by foaming and solidifying the resin component into a porous form. This roll for a continuous casting equipment uses the bearing unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing unit and a roll for continuous casting equipment using the same.

  Conventionally, in the bearing unit used for the roll for continuous casting equipment related to steel, an open type in which the seal itself is not provided is used, and new grease is periodically supplied and filled by centralized lubrication. Grease is discharged from the oil seal part of the housing to prevent water and contamination from entering. However, this method has a problem that the amount of grease used is large, and the cost and the burden on the surrounding environment are large.

  Therefore, as a method of using a sealed type bearing in which a seal is provided on the bearing itself and grease is filled inside the seal, a sealed bearing is interposed between the shaft and the bearing housing, In a bearing unit in which a grease sealing portion is provided between the bearing housing and the shaft and the grease sealing portions are communicated with each other by a bypass, the bypass can be set to either the inner diameter surface of the bearing housing or the outer diameter surface of the bearing. A bearing unit formed by a groove provided in one or both is known (see Patent Document 1). This bearing unit is shown in FIG.

  4A is a cross-sectional view showing a bearing unit used in a conventional roll for continuous casting equipment, and FIG. 4B is an enlarged cross-sectional view taken along line bb in FIG. 4A. FIG. 4 shows a bearing unit 2 that supports the shaft 1 on the free end side of a non-driving roll for continuous casting equipment, and the bearing 3 is interposed between the shaft 1 and the housing 4. A self-aligning roller bearing is used as the bearing 3, and double-row self-aligning rollers 7 are interposed between the inner ring 5 and the outer ring 6. Further, on the outer side of the roller 7, the lip 9, 9 of the bearing seal 8, 8 attached to the inner diameter surface of the outer ring 6 is brought into sliding contact with the outer diameter surface of the inner ring 5. The inside of the bearing inside the bearing seals 8, 8 is filled with grease 11. However, the seal 8, 8 prevents the leakage of the grease 11 to the outside. The inner ring 5 is attached to the shaft 1 by the stepped portion of the shaft 1 and the tightening member 12.

  Seal holders 13, 13 are provided on both sides of the housing 4, and oil seals 14, 14 and free end side oil seals 15 mounted on the seal holders 13, 13 are in sliding contact with the shaft 1. Grease 11 is filled inside the oil seals 14 and 14 and the free end side oil seal 15 to prevent water and contamination from entering.

  In this embodiment, the bypass 16 is formed by at least one groove (see FIG. 4A) provided on the inner diameter surface of the housing 4 in the axial direction. Both ends of the bypass 16 formed by the grooves reach the grease-filled ends on both sides, and the openings 17 and 17 are formed over the entire range of the grease 11 sealed. That is, each opening 17 is formed beyond the maximum movement range of the bearing 3. For this reason, even if the bearing 3 may move in the axial direction due to the influence of thermal expansion or the like, the bypass 16 is not blocked.

However, since the force acting on the bearing unit of the roll for continuous casting equipment is large, the size of the cross section of the bypass is limited due to the strength of the bearing housing, and grease cannot easily pass through. The seal may be deformed due to grease pressure during thermal expansion of the shaft.
Further, if grease is not put in the portion, there is a problem that the sealing performance is reduced accordingly.
JP 2002-206545 A

  The present invention has been made to cope with such a problem, and a bearing unit that does not deform a seal due to grease pressure during thermal expansion on both sides of the bearing, and a continuous unit using the same. It aims at providing the roll for casting facilities.

The bearing unit of the present invention includes a bearing with a seal between the shaft and the bearing housing, an oil seal is provided on both sides of the bearing with the seal, and grease is sealed between the bearing housing and the shaft and the oil seal. A bearing unit in which the bearing housing, the shaft, the oil seal, and the free end side oil seal communicate with each other by a bypass, wherein the bypass is at least one of the inner diameter surface of the bearing housing and the outer diameter surface of the bearing. A mixture including a lubricating component, a resin component, a curing agent, and a foaming agent is formed between the seal of the bearing with the seal, the bearing housing, and the free end side oil seal. It is characterized by enclosing a foamed solid lubricant obtained by foaming and curing.
Grease is sealed between a seal that seals between the inner ring and the outer ring of the bearing and the rolling element of the bearing, and between the housing, the free end side oil seal, and the free end side seal, The foamed solid lubricant is sealed.

Among the solid foam lubricants, the first solid foam lubricant is at least one lubricating component whose lubricating component is selected from hydrocarbon-based lubricants and hydrocarbon-based greases, and the resin component is a polymer main component. The chain is composed of hydrocarbons, and is a liquid rubber having a hydroxyl group in an amount such that the hydroxyl value is 25 mg KOH / g to 110 mg KOH / g at the end of the main chain, and the curing agent has an isocyanate group in the molecule It is an organic compound, the foaming agent is water, and the ratio of the liquid rubber and the curing agent is such that the hydroxyl group contained in the liquid rubber and the isocyanate group contained in the curing agent are equivalent (OH / NCO ) = 1 / (1.0 to 2.0), and the mixture contains 40 wt% to 80 wt% of the lubricating component and 5 wt% to 45 wt% of the liquid rubber with respect to the entire mixture. Features.
Further, the liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3500 having a hydroxyl group at the main chain terminal of a butadiene or isoprene polymer, or a modified hydroxyl group-terminated diene system obtained by hydrogenating the diene polymer. It is a polymer.
The organic compound having an isocyanate group in the molecule is a prepolymer having two or more isocyanate groups in the molecule and a ratio of the isocyanate group of 2.5 NCO% to 5.0 NCO%, or aromatic. It is a polyisocyanate.

Among the foamed solid lubricants, the second foamed solid lubricant is at least one lubricating component in which the lubricating component is selected from lubricating oil and grease, and the resin component has an isocyanate group content of 2% by weight. More than 6% by weight of urethane prepolymer, the foaming agent is water, and the mixture contains 30% to 70% by weight of the lubricating component with respect to the whole mixture, and the open cell ratio after foaming is It is characterized by being 50% or more. The urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.
Further, the ratio of the isocyanate group to the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). And
The ratio of the hydroxyl group of water to the functional group of the curing agent is an equivalent ratio (hydroxyl group of water / functional group of the curing agent) = 1 / (0.7 to 2.0).
The curing agent is an aromatic polyamino compound, particularly an aromatic polyamino compound having a substituent at a position adjacent to an amino group.

In the case where the bypass is provided on the inner diameter surface of the housing, both ends of the groove forming the bypass are formed so as to reach positions exceeding the moving range of the bearing.
When the bypass is provided on the outer diameter surface of the bearing, both end portions of the groove forming the bypass are formed so as to reach both ends of the bearing outer diameter surface.
In the case where the bypass is provided on the inner diameter surface of the housing and the outer diameter surface of the bearing, both ends of the groove forming the bypass on the housing side are formed so as to reach positions that exceed the moving range of the bearing, respectively. Both ends of the groove forming the bypass are formed so as to reach both ends of the outer diameter surface of the bearing.
The bearing is a self-aligning roller bearing.

  The roll for continuous casting equipment according to the present invention is characterized in that the bearing unit is provided on the free end side.

  The bearing unit of the present invention includes a bearing with a seal between the shaft and the bearing housing, an oil seal is provided on both sides of the bearing with the seal, and grease is sealed between the bearing housing and the shaft and the oil seal. A bearing unit in which the bearing housing, the shaft, the oil seal, and the free end side oil seal communicate with each other by a bypass, wherein the bypass is at least one of the inner diameter surface of the bearing housing and the outer diameter surface of the bearing. It is formed by a groove provided, and a lubricating component and a resin component are essential components between the seal of the sealed bearing, the bearing housing, and the free end oil seal, and the resin component is foamed and cured to be porous. Since the refined foamed solid lubricant is enclosed, the lubricating component that oozes out from the foamed solid lubricant is a lubricating oil and does not clog the bypass. Nor hinder that a uniform pressure on both sides.

  This foamed solid lubricant is a foamed solid lubricant which has a lubricating component and a resin component as essential components, and is made porous by foaming and curing the resin component, and the lubricating component is occluded in the foamed and cured solid component Is done. For this reason, the retained amount of the lubricating component in the foamed solid lubricant is larger than the retained amount by simple impregnation in the pores, which can contribute to the extension of the life of the bearing unit. Further, since the lubricating component is gradually released from the foamed solid lubricant to the sliding surface and sliding surface of the bearing during operation, it is possible to prevent leakage of excess lubricant. 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.

Further, since the foamed solid lubricant is easily deformed, a large force is not applied to the seal during the thermal expansion of the shaft, and the lubricating component that oozes out from the foamed solid lubricant during the deformation is the bearing housing. The seal life can be extended by being supplied to the seal portion.
In addition, since the entire space between the bearing housing and the bearing with seal is occupied by the foamed solid lubricant, it is possible to prevent intrusion of foreign matter from the outside. Even if grease leaks from the sealed bearing, the grease is taken into the foamed solid lubricant resin or bubbles, so that the grease can be prevented from leaking out of the bearing unit.

  An embodiment of a bearing unit of the present invention will be described with reference to the drawings. 1A is a cross-sectional view showing an embodiment of the bearing unit of the present invention, and FIG. 1B is an enlarged cross-sectional view taken along the line bb of FIG. 1A. As shown in FIG. 1, the bearing 3 is interposed between the shaft 1 and the housing 4. A self-aligning roller bearing is used as the bearing 3, and double-row self-aligning rollers 7 are interposed between the inner ring 5 and the outer ring 6. Further, on the outer side of the roller 7, the lip 9, 9 of the bearing seal 8, 8 attached to the inner diameter surface of the outer ring 6 is brought into sliding contact with the outer diameter surface of the inner ring 5. The inside of the bearing inside the bearing seals 8, 8 is filled with grease 11. However, the seal 8, 8 prevents the leakage of the grease 11 to the outside. The inner ring 5 is attached to the shaft 1 by the stepped portion of the shaft 1 and the tightening member 12.

Seal holders 13, 13 are provided on both sides of the housing 4, and oil seals 14, 14 and free end side oil seals 15 mounted on the seal holders 13, 13 are in sliding contact with the shaft 1.
The bearing unit 2 has a lubricating component and a resin component as essential components between the seal 8 of the bearing 3 with the seal, the bearing housing 4 and the free end oil seal 15, and the resin component is foamed and cured to be porous. A refined foamed solid lubricant 18 is enclosed. The bearing housing 4, the shaft 1, the oil seal 14, and the free end side oil seal 15 are communicated with each other by a bypass 16, and at least one bypass 16 is provided on the inner diameter surface of the bearing housing 4 in the axial direction. The groove is formed. Both ends of the bypass 16 formed by the grooves reach the ends where the grease 11 and the foamed solid lubricant 18 on both sides are sealed, and the grease 11 and the foamed solid lubricant in which the openings 17 and 17 are sealed. It is formed over the entire 18 range. That is, each opening 17 is formed beyond the maximum movement range of the bearing 3. For this reason, even if the bearing 3 may move in the axial direction due to the influence of thermal expansion or the like, the bypass 16 is not blocked.

  Since the bypass 16 is formed only by machining the axial groove on the inner diameter surface of the housing 4, the machining is easy.

2A is a sectional view showing another embodiment of the bearing unit of the present invention, and FIG. 2B is an enlarged sectional view taken along the line bb of FIG. 2A. As shown in FIG. 2, at least one bypass 16 formed by a groove is provided on the outer diameter surface of the outer ring 6 of the bearing 3 in the axial direction. Both ends of the bypass 16 reach both ends of the outer ring 6 and are formed over the entire range of the grease 11 and the foamed solid lubricant 18 in which the openings 17 and 17 opened in the axial direction are enclosed. Processing of the bypass 16 in this case is also simpler than drilling. If the bypass 16 is formed on the outer diameter surface of the bearing 3 as described above, the bypass 16 itself moves together with the bearing 3 regardless of how the bearing 3 moves, so that the openings 17 and 17 are closed. It will never be done.
Other configurations are the same as those in FIG.

3A is a sectional view showing another embodiment of the bearing unit of the present invention, and FIG. 3B is an enlarged sectional view taken along the line bb of FIG. 3A. As shown in FIG. 3, at least one bypass 16 formed by a groove is provided in the axial direction in each of two types of the inner diameter surface of the bearing housing 4 and the outer diameter surface of the outer ring 6 of the bearing 3. One type of both ends of the bypass 16 reach the end where the grease 11 and the foamed solid lubricant 18 on both sides are sealed, and the other type of both ends reach the both ends of the outer ring 6 and the opening 17. , 17 are formed over the entire range of the grease 11 and the foamed solid lubricant 18 encapsulated. Processing of the bypass 16 in this case is also simpler than drilling. If the bypass 16 is formed on the outer diameter surface of the bearing 3 as described above, the bypass 16 itself moves together with the bearing 3 regardless of how the bearing 3 moves, so that the openings 17 and 17 are closed. It will never be done.
Other configurations are the same as those in FIG.

1 to 3, the foamed solid lubricant 18 closes the opening 17 on the free end side. The foamed solid lubricant 18 has open cells that communicate with each other, and the foamed solid lubricant. The lubricating component that oozes out from the agent 18 is lubricating oil and does not clog the bypass 16, and does not hinder uniform pressure on both sides of the bearing 3. Further, since the foamed solid lubricant 18 is easily deformed, a large force is not applied to the seal 8 when the shaft 1 is thermally expanded, and the foamed solid lubricant 18 bleeds during the deformation. By supplying the lubrication component to be supplied to the seal portion of the bearing housing 4, the life of the seal 8 can be extended.
In addition, since the entire space between the bearing housing 4 and the bearing 3 with the seal is occupied by the foamed solid lubricant 18, it is possible to prevent entry of foreign matter from the outside. Further, even if the grease 11 leaks from the sealed bearing 3 through the seal lip 9, it can be taken into the resin or bubbles of the foamed solid lubricant 18, and the lubricating component can be supplied to the lip portion of the oil seal 14. The grease 11 can be prevented from leaking out of the bearing unit 2 and the life of the oil seal 14 can be extended.

The foamed solid lubricant encapsulated in the above-mentioned space portion allows the lubricating component to be occluded in the resin, so that due to the flexibility of the resin, the lubricant is oozed out by the external force applied or capillary action, and from outside the resin molecules to the outside. Slow release. 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. Further, the density of the foamed solid lubricant can be changed by controlling the blending amount of the blending components of the mixture.
Further, in the foamed solid lubricant used in the present invention, the resin component has a large surface area due to foaming, and the excess lubricating oil or the like that has oozed out can be temporarily retained in the foam bubbles again. The amount of lubricant to be discharged is stable. Further, by storing the lubricant in the resin and impregnating the bubbles, the retained amount of the lubricating oil or the like becomes larger than the non-foamed state. In addition, the energy required for bending is very small compared to a non-foamed body, and flexible deformation is possible while maintaining the lubricating component at a high density.

As the resin component constituting the foamed 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.

For the resin component of the foamed solid lubricant used in the present invention, it is preferable to use a urethane resin that is excellent in heat resistance and flexibility and can be reduced in cost. As the resin component, a first foamed solid lubricant using a liquid rubber having a hydroxyl group in the molecule described below and a second foamed solid lubricant using a urethane prepolymer containing a predetermined NCO are preferable.
Moreover, the resin component obtained by making the polyether polyol and polyisocyanate as a polyol react can be used.

As the resin component used in the first foamed solid lubricant that can be used in the present invention, it is preferable to use a urethane resin that is excellent in heat resistance and flexibility and can be reduced in cost. The hydroxyl group-containing component that forms the urethane resin is preferably a liquid rubber having a hydroxyl group in the molecule. This liquid rubber has a polymer main chain composed of hydrocarbons, and a hydroxyl value of 25 to 110 mg KOH at the end of the main chain. A liquid rubber having a hydroxyl group in an amount of / g 2 is preferable. When the hydroxyl value is less than 25 mg KOH / g, foaming / curing is not sufficient, and when the hydroxyl value exceeds 110 mg KOH / g, the elasticity of the foamed solid lubricant may be lost.
This liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3,500 having a hydroxyl group at the main chain terminal of a butadiene or isoprene polymer, or a modified hydroxyl group-terminated diene polymer obtained by hydrogenating the diene polymer. Coalescence can be used.
Examples of the hydroxyl-terminated liquid polybutadiene include poly-bd R45HT (manufactured by Idemitsu Kosan Co., Ltd.), poly-bd R15HT (manufactured by Idemitsu Kosan Co., Ltd.), NISSO-PB G-1000, G-2000, and G-3000 (manufactured by Nippon Soda Co., Ltd.). Examples of the hydroxyl group-terminated liquid polyisoprene include poly-ip (manufactured by Idemitsu Kosan Co., Ltd.), and examples of the hydrogenated hydroxyl group-terminated polydiene compound include Epol (manufactured by Idemitsu Kosan Co., Ltd.), NISSO-PB GI-1000, GI-2000, GI-3000 (made by Nippon Soda Co., Ltd.), etc. are mentioned.

  Further, the hydroxyl group-terminated polydiene compound or the hydroxyl group-terminated polydiene compound obtained by partially modifying the terminal hydroxyl group of the hydroxyl-terminated polydiene compound or the hydrogenated hydroxyl-terminated polydiene compound with an isocyanate group or an epoxy group or the hydrogenated hydroxyl-terminated polydiene compound is also included at the terminal. If it can be used. Two or more of these compounds may be mixed and used for the purpose of controlling the physical properties of the produced foam.

  The hydroxyl group-terminated polydiene polymer or the hydrogenated hydroxyl group-terminated polydiene polymer has a molecular structure similar to that of a lubricating component composed of paraffinic or naphthenic mineral oil composed of hydrocarbons, which will be described later. It is considered that the hydroxyl group-terminated polydiene polymer or the hydrogenated hydroxyl group-terminated polydiene polymer and the lubricating component molecule are intertwined by a relatively weak interaction. Therefore, many lubricating components can be impregnated in the molecule of the hydroxyl-terminated polydiene polymer or the hydrogenated hydroxyl-terminated polydiene polymer, and high lubricating component retention can be exhibited. By applying a strong force such as heat or centrifugal force to this, the interaction between the hydroxyl-terminated polydiene polymer or the hydrogenated hydroxyl-terminated polydiene polymer and the lubricating component is broken, and the lubricating component can be released gradually. it can.

The organic compound having an isocyanate group in the molecule as a curing agent for curing the liquid rubber can be used without particular limitation as long as it is an isocyanate compound that reacts with a hydroxyl group in the liquid rubber to extend the molecular chain or crosslink. Preferred isocyanate compounds include polyisocyanates. Polyisocyanates are particularly preferable because they can react with water to be a foaming agent described later to generate gas.
Examples of the polyisocyanates include polyisocyanates and / or prepolymers having two or more isocyanate groups in the molecule.

Polyisocyanates can include aromatic, aliphatic, or alicyclic polyisocyanates.
Aromatic polyisocyanates include tolylene diisocyanate (hereinafter referred to as TDI), diphenylmethane diisocyanate (hereinafter referred to as MDI), TDI multimer, MDI multimer, naphthalene diisocyanate (NDI), phenylene diisocyanate, diphenylene. Diisocyanate etc. are mentioned.
Examples of the aliphatic polyisocyanates include octadecamethylene diisocyanate, decamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and xylylene diisocyanate.
Examples of the alicyclic polyisocyanates include isophorone diisocyanate and dicyclohexylmethane diisocyanate.
Further, an adduct of the above polyisocyanate and a polyol such as trimethylolpropane can also be used.
When the reaction with the hydroxyl group that is the terminal functional group of the liquid rubber is performed at a high temperature, a blocked isocyanate in which an isocyanate group is blocked with a blocking agent such as phenols, lactams, alcohols, and oximes can be used. .

  In the case of reacting with a hydroxyl group-terminated polydiene polymer, aromatic polyisocyanates are preferred among the polyisocyanates, and TDI having excellent foamability and reactivity with the hydroxyl group-terminated polydiene polymer is preferred.

As the prepolymer having two or more isocyanate groups in the molecule, any prepolymer having an isocyanate group ratio of 2.5 to 5.0 NCO% can be used. In addition, NCO% is the weight% as an NCO group in a prepolymer. A 2.5 to 5.0 NCO% prepolymer can react with a hydroxyl group-terminated polydiene polymer or the like to obtain a urethane having high elasticity.
Prepolymers are classified into PPG type, PTMG type, ester type, caprolactone type, etc., depending on the type of monomer to be polymerized. There are Takenate L-1170 (manufactured by Mitsui Chemicals Polyurethane) and P-1158 (manufactured by Mitsui Chemicals Polyurethanes) in the PPG system, and Coronate 4090 (manufactured by Nippon Polyurethanes) in the PTMG system. Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), and Sianaprene 7-QM are used as caprolactones. (Mitsui Chemical Polyurethane Co., Ltd.), Plaxel EP1130 (Daicel Chemical Industries Co., Ltd.) and the like.
Two or more kinds of the prepolymers can be mixed and used according to the purpose.

  The blending ratio of the hydroxyl group-terminated polydiene polymer having a terminal hydroxyl group or the hydrogenated hydroxyl group-terminated polydiene polymer and the isocyanate compound having an isocyanate group is equivalent ratio of hydroxyl group (—OH) to isocyanate group (—NCO). The range of (OH / NCO) = 1 / (1.0 to 2.0) is preferable, and the range of (OH / NCO) = 1 / (1.1 to 1.9) is preferable in consideration of particularly excellent foamability and elasticity. When (OH / NCO) is smaller than 1 / 2.0, the isocyanate group becomes excessive, the crosslink density is large, and the elasticity may be poor. On the other hand, when (OH / NCO) is greater than 1 / 1.0, the crosslinking is insufficient and curing is not sufficient.

The lubricating component that can be used for the first foamed solid lubricant can be used as long as it does not dissolve the solid component that forms the foam. Examples of the lubricating component include hydrocarbon-based lubricants, hydrocarbon-based greases, and mixtures of hydrocarbon-based lubricants and hydrocarbon-based greases.
Examples of the hydrocarbon-based lubricating oil include paraffinic and naphthenic mineral oils, hydrocarbon-based synthetic oils, GTL base oils, and the like. These can be used alone or as a mixed oil.
The hydrocarbon-based grease is a grease having a hydrocarbon oil as a base oil, and examples of the base oil include the above-described hydrocarbon-based lubricating oil. Examples of the thickener include lithium soaps, lithium complex soaps, calcium soaps, calcium complex soaps, aluminum soaps, aluminum complex soaps, and other urea compounds such as diurea compounds and polyurea compounds. It is not a thing. The diurea compound is obtained by the reaction of diisocyanate and monoamine, and the polyurea compound is obtained by the reaction of diisocyanate and polyamine.

  As the lubricating component, hydrocarbon synthetic wax, polyethylene wax, higher fatty acid ester wax, higher fatty acid amide wax, ketone / amines, hydrogenated oil, and the like can be mixed and used.

  Since the means for foaming the first foamed solid lubricant uses an isocyanate compound as a raw material, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas.

The first solid foam lubricant is obtained by foaming and curing a mixture containing the above-described lubricating component, liquid rubber, a curing agent, and a foaming agent.
The blending ratio of the lubricating component is 40 to 80% by weight based on the entire mixture. When the lubricating component is less than 40% by weight, the supply amount of lubricating oil and the like is so small that it cannot function as a foamed solid lubricant, and when it exceeds 80% by weight, it does not solidify.
The blending ratio of the liquid rubber is 5 to 45% by weight, preferably 9 to 42% by weight, based on the entire mixture. When it is less than 5% by weight, it does not solidify, so it does not have a function as a foamed solid lubricant. When it is more than 45% by weight, the supply of the lubricant is small and it does not function as a foamed solid lubricant.

  In the first foamed solid lubricant, the expansion ratio is preferably 1.1 to 50 times, more preferably 1.1 to 10 times. When the expansion ratio is less than 1.1 times, the bubble volume is small and deformation cannot be allowed when external stress is applied. If it exceeds 50 times, it will be difficult to obtain the strength to withstand external stress.

  Moreover, in order to accelerate the curing rate of the first foamed solid lubricant, a tertiary amine catalyst, an organometallic catalyst, or the like can be used. Examples of the tertiary amine catalyst used include monoamines, diamines, triamines, cyclic amines, alcohol amines, ether amines and the like. Examples of the organometallic catalyst include stanaoctaate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin maleate, dioctyltin dimercaptide, dioctyltin thiocarboxylate and the like. Moreover, you may mix and use these multiple types for the purpose of adjusting the balance of reaction.

In the present invention, the urethane prepolymer that can be used as the resin component of the second foamed solid lubricant is obtained by a reaction between a compound having an active hydrogen group and a polyisocyanate, and the isocyanate group may be a molecular chain terminal, or It 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.
Depending on the type of monomer (= compound having an active hydrogen group) to be reacted, it is classified into caprolactone, ester and ether. Ether ethers include Takenate L-1170 (Mitsui Chemical Polyurethane), L-1158 (Mitsui Chemical Polyurethane), and Coronate 4090 (Nippon Polyurethane). Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), and Sianaprene 7-QM are used as caprolactones. (Manufactured by Mitsui Chemicals Polyurethane), Plaxel EP1130 (manufactured by Daicel Chemical Industries) and the like.
Moreover, the oligomer and prepolymer compound which modified the terminal group into the isocyanate group can also be used. Examples of such a compound include a terminal isocyanate-modified polyether polyol and an isocyanate-modified product of a hydroxyl group-terminated polybutadiene. Examples of the terminal isocyanate-modified polyether polyol include Coronate 1050 (manufactured by Nippon Polyurethane Co., Ltd.). Moreover, poly-bd MC50 (made by Idemitsu Kosan Co., Ltd.) and poly-bd HTP9 (made by Idemitsu Kosan Co., Ltd.) are mentioned as the isocyanate modified body of hydroxyl-terminated polybutadiene.
These urethane prepolymers can be used in a mixture of two or more depending on the intended mechanical properties.

As the second foamed solid lubricant, a urethane prepolymer having an isocyanate group content of 2 wt% or more and less than 6 wt% can be used. If the isocyanate group (NCO) content is less than 2% by weight, it will be difficult to achieve both foamability and elasticity, and if it is more than 6% by weight, the hardness will be too high and the rebound resilience will increase and deformation due to external force will occur. It becomes easy to generate heat when receiving.
Moreover, the isocyanate group can use the block isocyanate etc. which blocked the isocyanate group with blocking agents, such as phenols, lactams, alcohols, and oximes.

The curing agent for curing the urethane prepolymer is preferably a compound having active hydrogen, and examples thereof include a polyamino compound having a functional group as an amino group and a polyol compound having a functional group as a hydroxyl group.
Polyamino compounds include 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter referred to as MOCA), 3,3'-dimethyl-4,4'-diaminodiphenylmethane, and 3,3'-dimethoxy-4. , 4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, trimethylene-bis- (4-aminobenzoate), bis (methylthio) -2,4- Aromatics typified by toluenediamine, bis (methylthio) -2,6-toluenediamine, methylthiotoluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine Examples include polyamino compounds.

  Among the polyamino compounds, aromatic amino compounds are preferable because of low cost and excellent physical properties, and aromatic diamino compounds having a substituent at the position adjacent to the amino group are particularly preferable. In the 2nd foaming solid lubricant, since it passes through the process of hardening with foaming, it is thought that the reactivity of an amino group is suppressed by the substituent of an adjacent position.

  When the urethane prepolymer is cured with a polyamino compound, it becomes a foamed solid lubricant having urethane and urea bonds in the molecule. By generating urea bonds, the urethane bond density in the molecule is lowered, and elongation and impact resilience are improved. Moreover, rigidity can be provided by generating a urea bond.

  Examples of the polyol compound include low molecular polyols such as 1,4-butane glycol and trimethylolpropane, polyether polyols, castor oil polyols, and polyester polyols. Among the polyol compounds, polyether polyol and trimethylolpropane are preferable.

The ratio of the isocyanate group (—NCO) contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio when the functional group is an amino group or a hydroxyl group (functional group of the curing agent). /NCO)=1/(1.1 to 2.5).
The ratio of the isocyanate group contained in the urethane prepolymer, the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent, and the hydroxyl group of water (—OH) as the foaming agent, Flexibility, elasticity, etc. are determined. When the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent is reacted with the isocyanate group (—NCO) of the urethane prepolymer in an equivalent amount, an isocyanate group (—NCO) that reacts with water as the foaming agent is formed. Since it will disappear, the range of (functional group of curing agent / NCO) = 1 / (1.1 to 2.5) is preferable. Moreover, the ratio of the hydroxyl group of water which is a foaming agent and the functional group of a hardening | curing agent is the range of (hydroxyl group of water / functional group of a hardening | curing agent) = 1 / (0.7-2.0) by an equivalent ratio.
If the amount of the curing agent is less than the above range, not only the physical properties such as the strength of the foamed solid lubricant are remarkably lowered, but also the urethane elastomer may not be cured.

The lubricating component that can be used in the second foamed solid lubricant can be used as long as it does not dissolve the solid component that forms the foam, like the first foamed solid lubricant. As the lubricating component, for example, lubricating oil, grease, wax or the like can be used alone or in combination. Particularly preferred are hydrocarbon-based lubricants, hydrocarbon-based greases, or mixtures of hydrocarbon-based lubricants and hydrocarbon-based greases.
As the hydrocarbon-based lubricant, the same one as the first foamed solid lubricant can be used. In addition, ester synthetic oils, ether synthetic oils, fluorine oils, silicone oils and the like can also be used. These can be used alone or as a mixed oil.
As the grease, in addition to the grease similar to the first foamed solid lubricant, a grease based on ester synthetic oil, ether synthetic oil, GTL base oil, fluorine oil, silicone oil or the like can be used.
In addition, the same hydrocarbon-based synthetic wax, polyethylene wax, higher fatty acid ester-based wax, higher fatty acid amide-based wax, ketone / amines, hydrogenated oil, and the like as the first foamed solid lubricant may be used. it can.

As the foaming agent for foaming the second foamed solid lubricant, since an isocyanate compound is used as a raw material, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas.
Moreover, in order to accelerate the curing rate of the second foamed solid lubricant, the above-described tertiary amine catalyst, organometallic catalyst, or the like can be used.

The second foamed solid lubricant is obtained by foaming and curing a mixture containing the lubricating component, the resin component, the curing agent, and the foaming agent.
The blending ratio of the lubricating component is 30 to 70% by weight, preferably 40 to 60% by weight, based on the entire mixture. If the lubricating component is less than 30% by weight, the supply amount of lubricating oil or the like is so small that it cannot function as a foamed solid lubricant, and if it exceeds 70% by weight, it may not solidify.

  The open cell ratio of the second foamed solid lubricant after foaming is 50% or more, preferably 50% or more and 90% or less. When the open cell ratio is less than 50%, the ratio of the resin component (solid component) lubricating oil temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary. If it exceeds 90%, the oil retention of the lubricant will decrease and the amount of lubricant released will increase, which will be disadvantageous for long-term use, and the strength (durability) of the foamed solid lubricant itself will decrease. There is a fear.

The open cell ratio of the second solid foam lubricant can be calculated by the following procedure.
(1) The foamed solid lubricant that has been foam-cured is cut into an appropriate size to obtain sample A. The weight of sample A is measured.
(2) A is soxhlet washed (solvent: petroleum benzine) for 3 hours. Thereafter, the sample is left in a thermostatic bath at 80 ° C. for 2 hours to completely dry the organic solvent, and sample B is obtained. The weight of sample B is measured.
(3) The open cell ratio is calculated by the following procedure.
Open cell ratio = (1− (weight of resin component of sample B−weight of resin component of sample A) / weight of lubricating component of sample A) × 100
The resin component weight and the lubrication component weight of Samples A and B are calculated by multiplying the weights of Samples A and B by the composition charge ratio.
Lubricating components taken into discontinuous closed cells are not released to the outside by Soxhlet cleaning for 3 hours, so the weight of sample B is not reduced. The open cell ratio can be calculated as a result of the release of the lubricating component.

The first and second foamed solid lubricants may contain various additives such as pigments, antistatic agents, flame retardants, antifungal agents, reinforcing agents, inorganic fillers, anti-aging agents, and fillers as necessary. Can be added. Examples of the reinforcing agent include carbon black, white carbon, colloidal silica, and examples of the inorganic filler include calcium carbonate, barium sulfate, talc, clay, and meteorite powder.
In addition, 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, dinonylnaphthalene sulfone Rust inhibitors such as nates and sorbitan esters, 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, polymethacrylate, polystyrene Various additives such as a viscosity index improver such as

For the first and second foamed solid lubricants, it is possible to use a reactive impregnation method in which a foaming reaction and a curing reaction are simultaneously performed in the presence of a lubricating component such as a lubricating oil. It is desirable to achieve both elongation simultaneously. This is because the lubricant is uniformly impregnated into the foam formed in the foam during the foam formation stage, and the lubricant is occluded in the foamed / cured solid component, so that the lubricant is highly filled and the material properties It is considered that the high elongation of both is compatible.
On the other hand, after the foam is manufactured in advance, the post-impregnation method in which the lubricant is impregnated does not have sufficient lubricant holding power, and the lubricant is released in a short period of time and supplied when used for a long time. It becomes insufficient.

A method of mixing the mixture containing the lubricating component, the resin component, the curing agent, and the foaming agent is not particularly limited, and a commonly used agitator such as a Henschel mixer, a ribbon mixer, a juicer mixer, a mixing head, or the like. Can be mixed using.
Since the mixture is rapidly foamed and cured by the curing agent and the foaming agent, it is desirable to add the curing agent and the other components except the foaming agent to the stirrer and finally the curing agent and the foaming agent.
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.

In the bearing unit of the present invention, the foamed solid lubricant may be foamed and cured after pouring a mixture containing a lubricating component and a resin component into the bearing unit, and after foaming and curing at normal pressure, cutting, grinding, etc. Can be post-processed to the desired shape and incorporated into the bearing unit.
Since it is possible to easily fill any part in the bearing unit having a complicated shape, and a molding die and a grinding process for obtaining a foamed molded product are unnecessary, the mixture is used in the present invention. It is preferable to adopt a method of pouring into the bearing unit before foaming / curing and foaming / curing in the bearing unit. 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 that 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. May not be.

Examples 1 to 15 and Comparative Examples 1 to 4
The lubricating components, liquid rubber, curing agent, foaming agent, and catalyst used in Examples 1 to 15 and Comparative Examples 1 to 4 are shown below. In addition, () represents an abbreviation in the table.
Lubricating component Lubricating oil (lubricating oil): Turbine 100 (manufactured by Nippon Oil Corporation)
Lubricating grease (Grease 1): NTG2218M (manufactured by Kyodo Yushi Co., Ltd.)
Liquid rubber Hydroxyl-terminated polybutadiene (PBOH1): Poly-bd R45HT (hydroxyl value: 46.6 mg KOH / g, number average molecular weight: 2,800, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polybutadiene (PBOH2): Poly-bd R15HT (hydroxyl value: 102.7 mg KOH / g, number average molecular weight: 1,200, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polyisoprene (PipOH): Poly-ip (hydroxyl value: 46.6 mg KOH / g, number average molecular weight: 2,500, manufactured by Idemitsu Kosan Co., Ltd.)
Hydrogenated hydroxyl-terminated polyisoprene (HPipOH): Epol (hydroxyl value: 50.5 mg KOH / g, number average molecular weight: 2,500, manufactured by Idemitsu Kosan Co., Ltd.)
Curing agent Isocyanate compound (TDI): Coronate T-80 (manufactured by Nippon Polyurethane Co., Ltd.)
Elastomer 1 (UE1): Coronate 4090 (4.4 NCO% made by Nippon Polyurethane)
Elastomer 2 (UE2): Plaxel EP1130 (3.3 NCO% manufactured by Daicel Chemical Industries)
Foaming agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (Catalyst 1) DM70 (manufactured by Tosoh Corporation)

Mix well the compounding materials except the curing agent (isocyanate) at the blending ratios shown in Tables 1 to 3, and finally add 40 g of the mixture that was quickly mixed by adding the curing agent to a polytetrafluoroethylene resin container (70 mm in diameter). × Height 150 mm). After a few seconds, the foaming reaction started and allowed to stand at room temperature for several hours to be cured to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Further, when not cured as a foam, cases where the lubricating oil does not separate or release are marked with “x” and are also shown in Tables 1 to 3.
In addition, the test piece evaluated as “◯” showed no oil oozing even when it was stretched 20% in the direction of the cylinder axis of the test piece.

As shown in Tables 1 to 3, the foamed solid lubricants of Examples 1 to 15 are elastic rubber foams in which oil oozes out when a corresponding force is applied when pressed with a finger. Although it was recognized as an excellent foamed solid lubricant, in Comparative Examples 1 to 4, it was found that although foamed, it did not partially solidify and function as a foamed solid lubricant.
Next, in the bearing unit 2 shown in FIG. 1, the space between the seal 8 of the bearing with seal 3, the bearing housing 4, and the free end side oil seal 15 in the solid foam lubricant components of Examples 1 to 15 is shown. Then, it was allowed to stand for several hours at room temperature and cured to obtain a bearing unit in which the foamed solid lubricant 9 was enclosed.
Since this bearing unit encloses the foamed solid lubricant 9, the lubricating oil impregnated in the foamed solid lubricant 9 oozes out and does not clog the bypass, making the pressure on both sides of the bearing uniform. Thus, a bearing unit that does not deform the seal was obtained.

The lubricating components, urethane prepolymers, curing agents, foaming agents, and catalysts used in Examples 16 to 35 and Comparative Examples 5 to 7 are shown below. In addition, () represents an abbreviation in the table.
Lubricating component Lubricating oil (lubricating oil 1): Turbine 100 (paraffinic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 2): Crisef 150 (Naphthenic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 3): Sinfluid 801 (poly-α-olefin, manufactured by Nippon Steel Chemical Co., Ltd.)
Lubricating grease (Grease 2): Pyronic Universal N6C (manufactured by Nippon Oil Corporation)
Urethane prepolymer Caprolactan-based urethane prepolymer 1 (prepolymer 1): Plaxel EP1130 (NCO 3.3%, manufactured by Daicel Chemical Industries)
Ether-based urethane prepolymer (Prepolymer 2): Coronate 4090 (NCO 4.3%, manufactured by Nippon Polyurethane)
Ester urethane prepolymer (Prepolymer 3): Coronate 4047 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Caprolactan urethane prepolymer (Prepolymer 4): Takenate L-1350 (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 5): Takenate L-1170 (NCO 2.4%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 6): Takenate L-1680 (NCO 3.2%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 7): Cyanaprene 7-QM (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 8): Takenate L-1158 (NCO 4.4%, manufactured by Mitsui Chemicals Polyurethanes)
Hardener MOCA (MOCA): Iharacamine MT (manufactured by Ihara Chemical)
Trimethylene-bis- (4-aminobenzoate) (CUA-4): CUA-4 (manufactured by Ihara Chemical)
Mixture of bis (methylthio) -2,4-toluenediamine, bis (methylthio) -2,6-toluenediamine and methylthiotoluenediamine (Etacure 300): Etacure 300 (manufactured by Albemarle)
Trimethylolpropane: Reagent blowing agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (Catalyst 1) DM70 (manufactured by Tosoh Corporation)

Examples 16-18, 21, 22, 24, 25, 27-32, 34-35, Comparative Examples 5-7
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratios shown in Tables 4 to 6. Next, MOCA dissolved at 120 ° C. was put into a beaker and well stirred. Subsequently, an amine catalyst and a foaming agent (only Comparative Example 6 had no foaming agent) were added and stirred. After a few seconds, the foaming reaction started, and it was allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. In other cases, “Δ” mark or comments are also shown in Tables 4 to 6.
Further, the open cell ratio was measured by the above-described method, and the centrifugal oil separation evaluation was measured by the following method. The results are shown in Tables 4-6.
Centrifugal oil separation evaluation test Centrifugal oil separation was measured in order to examine the sustained release of the lubricant. Centrifugal oil separation showed the oil reduction rate relative to the oil filling amount when rotated for 1 hour under the conditions of a rotor radius of 75 mm and a rotation speed of 1500 rpm.

Example 19
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 100 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratio shown in Table 4. Next, trimethylene-bis (4-aminobenzoate) dissolved at 140 ° C. was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 4.

Examples 20, 26, 33
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratios shown in Tables 4 to 6. Next, Etacure 300 was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was left to cure at 100 ° C. for 30 minutes to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Are also shown in Tables 4-6.

Example 23
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratio shown in Table 5. Next, trimethylolpropane was put into the beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 5.

As shown in Tables 4 to 6, Examples 16 to 35 are elastic rubber foams in which oil oozes out when a corresponding force is applied when pressed with a finger, and excellent foam solid lubrication. In Comparative Example 5, it was found that although foamed, it did not partially solidify, and in Comparative Example 6, the resin component and the lubricant were separated and did not function as a foamed solid lubricant. . Comparative Example 7 lacked elasticity. Further, in Examples 16 to 35, it was found that the lubricant component was gradually released under the centrifugal force (without immediately leaving the foam).
Next, the spaces between the seal 8 of the bearing 3 with the seal, the bearing housing 4 and the free end side oil seal 15 in the bearing unit 2 shown in FIG. And then allowed to harden at 100 ° C. for 30 minutes to obtain a bearing unit in which the foamed solid lubricant 9 was enclosed.
Since this bearing unit encloses the foamed solid lubricant 9, the lubricating oil impregnated in the foamed solid lubricant 9 oozes out and does not clog the bypass, making the pressure on both sides of the bearing uniform. Thus, a bearing unit that does not deform the seal was obtained.

  In the bearing unit of the present invention, the grease sealing portion provided between the bearing housing and the shaft is communicated by bypass on both outer sides of the bearing, and a foamed solid lubricant is provided between the bearing housing and the sealed bearing. Since it is enclosed, the lubricating component that oozes out from the foamed solid lubricant is lubricating oil, and does not clog the bypass, and does not hinder uniform pressure on both sides of the bearing. For this reason, it can utilize suitably for a bearing unit and the bearing apparatus for continuous casting equipment using the same.

(A) It is sectional drawing which shows one Example of the bearing unit of this invention. (B) It is an expanded sectional view of the bb line of (a) figure. (A) It is sectional drawing which shows the other Example of the bearing unit of this invention. (B) It is an expanded sectional view of the bb line of (a) figure. (A) It is sectional drawing which shows the other Example of the bearing unit of this invention. (B) It is an expanded sectional view of the bb line of (a) figure. It is sectional drawing which shows the bearing unit used for the roll for the conventional continuous casting equipment. (B) It is an expanded sectional view of the bb line of (a) figure.

Explanation of symbols

1 shaft 2 bearing unit 3 bearing (with seal) 4 housing 5 inner ring 6 outer ring 7 roller 8 seal 9 lip 11 grease 12 tightening member 13 seal holder 14 oil seal 15 free end side oil seal 16 bypass 17 opening 18 foamed solid lubricant

Claims (17)

A bearing with a seal is interposed between the shaft and the bearing housing, an oil seal is provided on both sides of the bearing with the seal, grease is sealed between the bearing housing, the shaft and the oil seal, and the bearing housing and the shaft A bearing unit in which an oil seal and a free end side oil seal are communicated by a bypass,
The bypass is formed by a groove provided in at least one of the inner diameter surface of the bearing housing and the outer diameter surface of the bearing;
In addition, a mixture containing a lubricating component, a resin component, a curing agent, and a foaming agent is foamed and cured between the seal of the bearing with the seal, the bearing housing, and the free end side oil seal. A bearing unit characterized by enclosing a foamed solid lubricant.   Grease is sealed between a seal for sealing between the inner ring and the outer ring of the bearing and a rolling element of the bearing, and between the housing, the free end side oil seal, and the free end side seal, The bearing unit according to claim 1, wherein the foamed solid lubricant is enclosed. The lubricating component is at least one lubricating component selected from a hydrocarbon-based lubricating oil and a hydrocarbon-based grease;
The resin component is a liquid rubber in which the polymer main chain is composed of hydrocarbons and has hydroxyl groups in an amount such that the hydroxyl value is 25 to 110 mg KOH / g at the ends of the main chain.
The curing agent is an organic compound having an isocyanate group in the molecule,
The blowing agent is water;
The ratio of the liquid rubber and the curing agent is such that the hydroxyl group contained in the liquid rubber and the isocyanate group contained in the curing agent are in an equivalent ratio of (OH / NCO) = 1 / (1.0 to 2.0). ,
The bearing unit according to claim 1 or 2, wherein the mixture contains 40 to 80% by weight of the lubricating component and 5 to 45% by weight of the liquid rubber with respect to the whole mixture.   The liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3,500 having a hydroxyl group at the main chain end of a butadiene or isoprene polymer, or a modified hydroxyl group-terminated diene polymer obtained by hydrogenating the diene polymer. The bearing unit according to claim 3, wherein:   The organic compound having an isocyanate group in the molecule is a prepolymer having two or more isocyanate groups in the molecule and a ratio of isocyanate groups of 2.5 to 5.0 NCO%. The bearing unit according to claim 4.   5. The bearing unit according to claim 3, wherein the organic compound having an isocyanate group in the molecule is an aromatic polyisocyanate. The lubricating component is at least one lubricating component selected from lubricating oil and grease;
The resin component is a urethane prepolymer having an isocyanate group content of 2 wt% or more and less than 6 wt%,
The blowing agent is water;
The bearing unit according to claim 1, wherein the mixture includes 30 to 70% by weight of the lubricating component with respect to the entire mixture, and an open cell ratio after foaming is 50% or more.   The bearing unit according to claim 7, wherein the urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.   The ratio of the isocyanate group and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). The bearing unit according to claim 7 or 8.   The ratio of the hydroxyl group of the water to the functional group of the curing agent is an equivalent ratio (water hydroxyl group / functional group of the curing agent) = 1 / (0.7 to 2.0). The bearing unit according to claim 9.   The bearing unit according to claim 7, wherein the curing agent is an aromatic polyamino compound.   The bearing unit according to claim 11, wherein the aromatic polyamino compound is an aromatic polyamino compound having a substituent at a position adjacent to an amino group.   The said bypass is provided in the internal-diameter surface of the said housing, The both ends of the groove | channel which forms the bypass are formed so that it may reach the position which exceeds the moving range of a bearing, respectively. Bearing unit.   2. The bearing unit according to claim 1, wherein when the bypass is provided on the outer diameter surface of the bearing, both ends of the groove forming the bypass reach the both ends of the bearing outer diameter surface. .   In the case where the bypass is provided on the inner diameter surface of the housing and the outer diameter surface of the bearing, both ends of the groove forming the bypass on the housing side are formed so as to reach positions that exceed the moving range of the bearing, respectively. 2. The bearing unit according to claim 1, wherein both ends of the groove forming the bypass are formed so as to reach both ends of the bearing outer diameter surface.   The bearing unit according to claim 1, wherein the bearing is a self-aligning roller bearing.   A roll for continuous casting equipment, wherein the bearing unit according to any one of claims 1 to 16 is provided on a free end side.

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