JP2008297370A - Bearing holding foamed solid lubricant sealed therein, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing holding a foamed solid lubricant sealed therein which is excellent in the lubricating performance of the solid lubricant holding a lubricating oil, has a long life, can be operated even at a high speed rotation, can be made in relatively simple processes, and can respond to the demand of cost reduction. <P>SOLUTION: The bearing in which a foamed solid lubricant 37 is sealed in a bearing 31 is characterized in that the foamed solid lubricant 37 is a porous solid product containing a lubricating component and a resin component as essential components and produced by foaming and curing the resin component; the foamed solid lubricant contains a resin component comprising a resin or rubber having rubbery elasticity, and has the oozing property of the lubricating component by deformation with an external force; and the resin component is a polyurethane resin. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a foamed solid lubricant sealed bearing and a method for manufacturing the same.

  Generally, a lubricant is used in a sliding part and a rotating part of most machines represented by automobiles and industrial machines. Normally, rolling bearings are filled with grease to lubricate the friction surfaces between the rolling elements, bearing inner and outer rings and cage, so that the filled grease does not flow out to the outside. A sealing device such as a seal is provided so that dust and moisture do not enter. However, even for rolling bearings with a sealing device, it is difficult to completely seal the grease, and when it is used for a long time, the grease gradually flows out, or the grease gradually deteriorates due to moisture entering from the outside into the bearing. Sometimes. In order to solve the problems related to grease sealing failure and deterioration prevention, it is possible to prevent grease from splashing and dripping by retaining lubricating oil with increased lubricating oil and retaining liquid lubricant. Solid lubricants are also known.

For example, a solid lubricant in which ultra-high molecular weight polyolefin or urethane resin and its curing agent are mixed in lubricating oil or grease, and a liquid lubricant component is held between the resin molecules to gradually exude physical properties. It is known (see Patent Documents 1 to 3).
Also known is a self-lubricating polyurethane elastomer obtained by reacting a polyol, which is a polyurethane raw material, with a diisocyanate in a lubricating component in the presence of a lubricant (see Patent Document 4).
In addition, an oil-containing foam is known in which a solid component, which is a resin component, is made into a foam, and this is post-impregnated with a lubricating oil, and is provided in the vicinity of a friction contact portion inside the bearing (see Patent Document 5).

When these solid lubricants are sealed in a bearing and solidified, they gradually exude lubricating oil, which eliminates the need for maintenance to replenish the lubricating oil and makes severe use with a lot of moisture. It is intended to be useful for extending the life of bearings in environments and environments where strong inertial forces are applied.
On the other hand, a lubricating composition in which a lubricating oil is contained in a polyurethane resin produced from a polyol component and an isocyanate component is known (see Patent Documents 6 to 8).
In addition, a hydroxyl-terminated polydiene compound has been reported as a raw material that can be oil-extended by bitumen or the like. (See Patent Document 9)

However, in the rolling bearing filled with the solid lubricant according to the above-mentioned prior art, it is used because the resin component which is a base material melts due to short life, easy to seize at high speed rotation, and large heat generation. There is a problem that you can not. In the full pack specification, in the process of solidifying the solid lubricant in the bearing and then cooling, depending on the heating conditions, the solid lubricant contracts during curing, and the solid lubricant itself entraps the rolling elements. Therefore, there is a problem that the rotational torque at the start of the bearing tends to increase and heat is likely to be generated. Further, depending on the use conditions of the bearing used, the solid lubricant may be deformed to the bearing outer ring side by the centrifugal force during rotation, and the lubricant may not be supplied appropriately.
In addition, in the process of manufacturing such a solid lubricant, many manufacturing processes are required for reliably impregnating the lubricant and grease, and it is difficult to meet the demand for cost reduction.
JP-A-6-41569 JP-A-6-172770 JP 2000-319681 A JP-A-11-286601 Japanese Patent Laid-Open No. 9-42297 JP-A-60-173010 Japanese Patent Laid-Open No. 62-241997 JP-A-8-3259 JP 58-189243 A

  The present invention has been made in order to address such problems, and is excellent in the lubrication performance of a solid lubricant that holds lubricating oil, can be operated even at high speed rotation with a long service life, and the manufacturing process can be reduced. An object of the present invention is to provide a foamed solid lubricant-encapsulated bearing that can be made relatively simple and can meet the demand for cost reduction, and a method for manufacturing the same.

The foamed solid lubricant encapsulated bearing of the present invention is a foamed solid lubricant formed by foaming and curing a mixture containing a lubricating component, a resin component, a curing agent, and a foaming agent, and enclosed in the bearing internal space. The foamed solid lubricant has a foaming ratio of 1.1 times or more and less than 20 times and a foam molding shrinkage ratio of 5% or less.
In addition to the above characteristics, the foamed solid lubricant has the following characteristics: (1) The oil separation rate is 1% or more and 15% or less after 5 hours after applying a force of 80.3 gf, (2 ) The tensile strength measured according to Japanese Industrial Standard K6400 is 50 kPa or more, and / or (3) the open cell ratio is 50% or more.

The first foamed solid lubricant that can be used in the foamed solid lubricant-enclosed bearing of the present invention is such that the lubricating component is at least one lubricating component selected from hydrocarbon-based lubricating oil and hydrocarbon-based grease, and the resin component Is a liquid rubber having a hydroxyl group in the molecule, the liquid rubber having a hydroxyl group in an amount such that the polymer main chain is composed of hydrocarbon and the hydroxyl value is 25 to 110 mgKOH / g at the end of the main chain The curing agent is an organic compound having an isocyanate group in the molecule, the foaming agent is water, and the ratio of the liquid rubber to the curing agent is included in the hydroxyl group and the curing agent contained in the liquid rubber. Is equivalent to (OH / NCO) = 1 / (1.0 to 2.0) in an equivalent ratio, and the mixture contains 40 to 80% by weight of the lubricating component and the liquid rubber with respect to the whole mixture. 5 to 45% by weight It is characterized by that.
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 the ratio of the isocyanate group is 2.5 NCO% to 5.0 NCO%, or an aromatic polyisocyanate. It is characterized by being.

The second foamed solid lubricant that can be used in the foamed solid lubricant-encapsulated bearing of the present invention is such that the lubricating component is at least one lubricating component selected from lubricating oil and grease, and the resin component is an isocyanate group in the molecule. 2 wt% or more and less than 6 wt% of the urethane prepolymer, the foaming agent is water, and the mixture contains 30 to 70 wt% of the lubricating component with respect to the entire mixture. It is characterized by a bubble rate of 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 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). To do.
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.

  The manufacturing method of the solid foamed lubricant encapsulated bearing of the present invention includes a mixing step of mixing a component including a lubricating component, a resin component, a curing agent, and a foaming agent, and the mixture obtained in the mixing step is foam-cured. It is characterized by comprising a step of encapsulating inside the bearing before and a step of foaming and hardening in the bearing internal space after enclosing.

  The foamed solid lubricant-enclosed bearing of the present invention has a foamed solid lubricant enclosed in the bearing internal space, has a foaming ratio of 1.1 to 20 times, and a foam molding shrinkage of 5% or less. In addition to the characteristics, (1) The oil separation rate after continuous application of a force of 80.3 gf after 5 hours is 1% or more and 15% or less. (2) Tensile strength measured according to Japanese Industrial Standard K6400 Is 50 kPa or more, and / or (3) the open cell ratio is 50% or more, it is possible to suppress insufficient supply of lubricant due to rotational torque and centrifugal force during startup.

The foamed solid lubricant used in the present invention is occluded in the solid component in which the lubricating component is foamed and cured. For this reason, in the solid foam lubricant bearing of the present invention, the retained amount of the lubricating component in the solid foam lubricant is larger than the retained amount due to impregnation in the pores, and moreover than in the solid foam lubricant during operation. Since the lubricating oil is gradually released around the moving body and the like, it can be operated even at high speed rotation, which can contribute to a long 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.
Further, by encapsulating the foamed solid lubricant, the lubricant can be present near the rolling surface, and the lubricant is more easily supplied to the rolling surface than grease lubrication. It also serves as a seal member against the entry of dust and moisture from the outside. In addition, since it has many porous portions, it is advantageous in terms of reducing the weight of the bearing.
Since the manufacturing method of the present invention does not need to enclose a lubricant after assembly, the production efficiency is improved and the manufacturing can be performed at a low cost.

The foamed solid lubricant enclosed in the bearing internal space of the foamed solid lubricant-enclosed bearing of the present invention has a foaming ratio of 1.1 to 20 times, preferably 1.1 to 10 times, and a foam molding shrinkage of 5 % Or less.
Here, the expansion ratio is a value obtained by dividing the volume of the solid lubricant after foaming by the volume of the raw material mixed liquid before foaming. Further, the foam molding shrinkage ratio can be calculated as follows: [100 × (100 × (A)] when the raw material mixed liquid is put into a mold and foamed and the dimension of the mold is A and the dimension of the foamed solid lubricant after molding is taken out from the mold. A−B) / A].
If 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 a bug. If it is 20 times or more, it is difficult to obtain the strength to withstand external stress, which may lead to breakage or destruction.
If the foam molding shrinkage rate exceeds 5%, the solid lubricant shrinks greatly on the rolling elements, and the rotational torque at start-up tends to be insufficient.

In addition to the above properties, the foamed solid lubricant has (1) oil separation rate of 1% or more and 15% or less after 5 hours of continuous application of a force of 80.3 gf. (2) Japanese Industrial Standard K6400 And / or (3) the open cell ratio is 50% or more.
The oil separation rate measured by the above method is in the range of 1% to 15%. When it is less than 1%, the lubricant supply is insufficient. If it is 15% or more, the supply of lubricant becomes excessive, which hinders long-term supply of lubricant.
The tensile strength of the foamed solid lubricant is 50 kPa or more. If the pressure is less than 50 kPa, the material strength is insufficient, and the material is biased toward the outer ring by centrifugal force during rotation of the shaft, which may result in insufficient supply of appropriate lubricant.
The open cell ratio after foaming is 50% or more, preferably 50 to 90%. 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 open cell ratio 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 foamed solid lubricant having the above-described characteristics is obtained by foaming and curing a mixture containing a lubricating component, a resin component, a curing agent, and a foaming agent.
The foamed solid lubricant-encapsulated bearing of the present invention occludes a lubricating component in the resin of the encapsulated foamed solid lubricant. Therefore, due to the flexibility of the resin, for example, deformation due to external force such as compression, expansion, bending, torsion, and capillary action Thus, the lubricant can be exuded and released from between the resin molecules to the outside. At this time, the amount of the lubricating oil that oozes out can be minimized by changing the degree of elastic deformation according to the magnitude of the external force by selecting the resin.
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 that has oozed out can be temporarily retained in the foam bubbles again and ooze out. The amount of lubricating oil is stable, and the amount of lubricating oil retained is larger than that in a non-foamed state by occluding the lubricant in the resin and impregnating the bubbles.

In addition, the foamed solid lubricant used in the present invention requires much less energy when bent compared to non-foamed materials, and can be flexibly deformed while holding the lubricating oil at a high density. Therefore, in the process of cooling after solidifying the foamed solid lubricant, even if the solid lubricant contracts and embraces the rolling element, it can be easily deformed because the energy required for bending and deformation is small, The problem of increased rotational torque can be prevented. Moreover, since it has many foamed parts, ie, a porous part, it is advantageous also at the point of weight reduction.
In addition, since the foamed solid lubricant used in the present invention only foams and cures a mixture containing a lubricating component and a resin component as essential components, no special equipment is required, and it is filled and molded in any place. Is possible.
Further, the density of the foamed solid lubricant can be changed by controlling the blending amount of the blending components of the mixture.

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.

As the resin component of the 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. 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 used as the foamed solid lubricant. 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 for the first foamed solid lubricant, 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, and the liquid rubber has a polymer main chain composed of hydrocarbons, and a hydroxyl value of 25 to 110 mgKOH / A liquid rubber having a hydroxyl group in an amount of g is preferred. 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.
As the hydroxyl-terminated liquid polybutadiene, poly-bd R45HT (made by Idemitsu Kosan Co., Ltd.), poly-bd R15HT (made by Idemitsu Kosan Co., Ltd.), NISSO-PB G-1000, G-2000, G-3000 (made by Nippon Soda Co., Ltd.) are available. Examples of the hydroxyl group-terminated liquid polyisoprene include poly-ip (manufactured by Idemitsu Kosan Co., Ltd.). 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.
Also, an adduct of the polyisocyanate and a polyol such as trimethylolpropane can 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. Here, NCO% means NCO wt% contained in the whole 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 Polyurethanes) in the PPG system and L-1158 (manufactured by Mitsui Chemicals Polyurethanes), 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 above 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 view 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. If 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 if it exceeds 80% by weight, it will 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.

  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.

The urethane prepolymer that can be used as the resin component of the second foamed solid lubricant in the present invention is obtained by reacting a compound having an active hydrogen group with 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. Examples of ethers include Takenate L-1170 (Mitsui Chemical Polyurethane), L-1158 (Mitsui Chemical Polyurethane), 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 combination of two or more depending on the desired 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 foaming agent of the second foamed solid lubricant is preferably water that reacts with the isocyanate compound to generate carbon dioxide gas.

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.
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 and the like is so small that it cannot function as a foamed solid lubricant, and if it exceeds 70% by weight, it does not solidify.

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 fats, antioxidants such as amines and phenols, petroleum sulfonates, dinonylnaphthalene sulfone Antirust agents 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.

The manufacturing method of the foamed solid lubricant encapsulated bearing of the present invention includes a mixing step of mixing the above-described lubricating component, a resin component, a curing agent, and a component containing a foaming agent, and a mixture obtained in this mixing step is foamed. A step of encapsulating in the bearing before curing, and a step of foaming and curing in the bearing internal space after the encapsulation.
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 mixture is encapsulated inside the bearing before foam curing and then foamed. 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.

  These foamed solid lubricants can be encapsulated in various well-known types of bearings. 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.

An example of the solid foam lubricant bearing according to the present invention will be described with reference to FIG. FIG. 5 is a sectional view of a deep groove ball bearing according to an embodiment of the present invention.
As shown in FIG. 5, the bearing 31 includes an inner ring 32, an outer ring 33 disposed concentrically with the inner ring 32, a plurality of rolling elements 34 interposed between the inner and outer rings, and the plurality of rolling elements 34. It is comprised by the holder | retainer 36 to hold | maintain and the sealing member 35 fixed to the outer ring | wheel 33 grade | etc.,. The foamed solid lubricant 37 is sealed around at least the rolling element 34.

An example of a method for enclosing the foamed solid lubricant in the bearing will be described with reference to FIGS.
FIG. 1 is a schematic view showing an example of sealing in a radial ball bearing (without a seal member) according to another embodiment of the present invention. As shown in FIG. 1, a bearing 1 having an inner ring 2, an outer ring 3, and rolling elements 4 interposed between the inner and outer rings is placed on an iron plate 5 larger than the bearing outer diameter 7 or a jig similar thereto. The well-mixed foamed solid lubricant component 6 immediately before foaming is poured into a space surrounded by the inner ring 2, the outer ring 3, and the iron plate 5 to be foamed and cured. In this case, after pouring the mixture 6 into the bearing 1, an iron plate 5 larger than the bearing outer diameter 7 or a similar jig may be covered on the bearing 1. When the steel plate or jig is covered, the filling rate of the foamed solid lubricant in the bearing is improved. After completion of foaming / curing of the mixture 6, the iron plate 5 or a similar jig is removed to obtain a foamed solid lubricant sealed bearing.

  FIG. 2 is a schematic view showing an example of sealing in a radial ball bearing (with a seal member) according to another embodiment of the present invention. As shown in FIG. 2, the bearing 11 having the inner ring 12, the outer ring 13, the rolling elements 14 interposed between the inner and outer rings, and the seal member 15 mounted only on one side is arranged with the seal member 15 on the lower side. Leave still. Then, the well-stirred foam solid lubricant component mixture 16 immediately before foaming is poured into the bearing 11 and foamed and cured. In this case, in order to improve the filling rate of the foamed solid lubricant in the bearing as in FIG. 1, after the mixture 16 is poured into the bearing 11, an iron plate larger than the outer diameter of the bearing is formed on the bearing 11 or similar to it. You may put a jig. The upper seal member may be attached during the foaming process instead of a jig for improving the filling rate, or may be attached to the bearing 11 after foaming / curing is completed.

FIG. 3 is a schematic view showing an example of encapsulation in a thrust ball bearing according to another embodiment of the present invention. FIG. 4 is a schematic diagram showing the use of the cylindrical jig in FIG. As shown in FIGS. 3 and 4, a mold 25 in which a thrust ball bearing 21 is accommodated is prepared, and a bearing 21 having an inner ring 22, an outer ring 23, and rolling elements 24 interposed between the inner and outer rings is installed. A mixture 26 of the foamed solid lubricant component just before foaming, which is well stirred from the inner diameter side of the bearing 21, is poured into the bearing 21, and a cylindrical jig 27 having the same diameter as the inner diameter is inserted into the inner diameter portion and foamed and cured. After the mixture 26 is foamed and cured to become a foamed solid lubricant 28, the mold 25 and the cylindrical jig 27 are removed to obtain a foamed solid lubricant-enclosed bearing.
An injection molding machine or the like can also be used to enclose the lubricant in the bearing. In this case, the bearing is mounted on a mold, and the foamed solid lubricant component mixed in the screw is sealed into the bearing from the nozzle.

  In the foamed solid lubricant encapsulated bearing of the present invention, the lubricating component contained in the state impregnated in the foamed solid lubricant does not exude suddenly even when the foam is deformed by an external force, and the lubricating component is efficiently slid. It can be used by oozing to the moving surface. As a result, the bearing requires a minimum amount of lubrication component, has a long life, and can be operated even at high speed.

EXAMPLES The present invention will be further described below with reference to examples of the present invention, but the present invention is not limited thereby.
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 mgKOH / g, number average molecular weight: 2,800, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polybutadiene (PBOH2): Poly-bd R15HT (hydroxyl value: 102.7 mgKOH / g, number average molecular weight: 1,200, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polyisoprene (PipOH): Poly-ip (hydroxyl value: 46.6 mgKOH / g, number average molecular weight: 2,500, manufactured by Idemitsu Kosan Co., Ltd.)
Hydrogenated hydroxyl-terminated polyisoprene (HPipOH): Epol (hydroxyl value: 50.5 mgKOH / 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 in which oil oozes out 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.
The test piece evaluated as “◯” showed no oil oozing even when it was stretched 25% in the direction of the cylinder axis of the test piece.

  The expansion ratios of the above test pieces measured by the method described later are all 1.1 times to less than 20 times, the foam molding shrinkage rate is 5% or less, the oil separation rate is 1% to 15%, the tensile strength is 50 kPa or more, continuous The bubble rate was 50-90%.

  Further, the blending materials excluding the curing agent were mixed well in the polytetrafluoroethylene resin container (diameter 70 mm × height 150 mm) at the blending ratios shown in Tables 1 and 2. Next, after adding a hardening | curing agent and mixing rapidly, this mixture was filled into the interior space of the ball bearing 6204. FIG. After a few seconds, the foaming reaction started and allowed to stand at room temperature to be cured to obtain a test piece of a foamed solid lubricant-sealed bearing. Using this test piece, the following actual machine durability test was performed to evaluate the durability of the actual machine.

<Real machine durability test>
When the load of Fa = Fr = 67 N is applied to the obtained specimen and rotated at 10000 rpm at 100 ° C., the input current of the motor driving the rotating shaft exceeds the limit current (the rotational torque is The lifetime was measured until it exceeded twice the starting torque. As an evaluation, “○” marks were given to those that showed a lifetime exceeding 1000 hours, and “x” was indicated otherwise. The results are shown in Tables 1 and 2.

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.
Moreover, the ball bearing which enclosed the foaming solid lubricant of Example 1- Example 15 was excellent in actual machine durability.

Examples 16 to 35 and Comparative Examples 5 to 10
The lubricating components, urethane prepolymers, curing agents, foaming agents, and catalysts used in Examples 16 to 35 and Comparative Examples 5 to 10 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): Pyronock Universal N6C (manufactured by Nippon Oil Corporation)
Lubricating grease (Grease 3): Li-based grease NKG708 (manufactured by Kyodo Yushi Co., Ltd.)
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)
Polyol Polyether polyol (Polyol 1): Preminol SX4004 (Asahi Glass Co., Ltd.)
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 Isocyanate compound (TDI): Coronate T-80 (manufactured by Nippon Polyurethane)
Foaming agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (Catalyst 1) DM70 (manufactured by Tosoh Corporation)

  The urethane prepolymer, foam stabilizer, lubricating oil, and grease were mixed well at the blending ratios shown in Tables 4 to 6, and then the curing agent was added and mixed quickly. When the curing agent was MOCA, the mixing temperature was 80 ° C., and MOCA was dissolved and added at 120 ° C. When the curing agent was CUA-4, the mixing temperature was 100 ° C., and CUA-4 was dissolved and added at 140 ° C. When the curing agent was Etacure 300 and trimethylolpropane, the mixing temperature was 80 ° C. Finally, a foaming agent and an amine catalyst are added and stirred, and then the interior space of the ball bearing 6204 is filled. After that, the foamed solid lubricant is filled in a constant temperature bath set at 120 ° C. for 1 hour to cure. It was. Moreover, the foam was manufactured in the polytetrafluoroethylene beaker similarly to the above, and the sample for a measurement was obtained.

In the case of Example 18, polyether polyol, foam stabilizer, lubricating oil, amine catalyst, and water as a foaming agent were added, and the mixture was heated at 90 ° C. and stirred well. This was added with isocyanate and stirred well, filled in the internal space of the ball bearing 6204, and then left in a thermostatic bath set at 90 ° C. for 15 minutes to obtain a foamed solid lubricant-enclosed bearing. Moreover, the foam was manufactured in the polytetrafluoroethylene beaker similarly to the above, and the sample for a measurement was obtained.
In the case of Comparative Example 6, the foam was filled into the internal space of the ball bearing 6204 in the same manner as in Example 1 except for the lubricating oil among the components (compositions) shown in Table 6. Lubricating oil was impregnated later to form a post-impregnated foamed lubricant encapsulated bearing.

The following evaluation was performed using the obtained measurement sample and the foamed solid lubricant-enclosed ball bearing. The results are shown in Tables 4-6.
<Foaming ratio>
The expansion ratio was determined as [volume after foaming / volume of liquid before foaming].
<Shrinkage rate>
The shrinkage rate was determined from the shrinkage of the dumbbell dimensions used in the tensile test. Specifically, it was determined by the following formula.

Shrinkage rate (%) = 100 × shrinkage length of the dumbbell after molding (longitudinal direction) / mold size
= 100 x (mold dimension-dimension after molding) / mold dimension

<Open cell ratio>
The open cell ratio was measured by the method described above.
<Tensile strength>
The test was conducted according to JISK6400. As the dumbbell test piece, a polytetrafluoroethylene mold was prepared, and a foam dumbbell having a thickness of 5 mm was prepared by pouring the raw material before foaming.
<Oil separation rate>
The oil separation rate was evaluated as the lubricant supply ability. The test piece was cut out to about 1.5 g, and the weight before measurement was measured with a precision balance. Using a commercially available centrifuge, the weight after measurement after 5 hours at a rotation speed of 850 rpm and a rotation radius of 100 mm (equivalent to 80.3 gf) was again weighed with a precision balance and calculated by the following formula.

Oil separation rate (%) = 100 × Lubricant release amount / weight before measurement
= 100 × (weight before measurement−weight after measurement) / weight before measurement

<Bearing life time>
When the load of Fa = Fr = 67 N is applied to the obtained specimen and rotated at 10000 rpm at 100 ° C., the input current of the motor driving the rotating shaft exceeds the limit current (the rotational torque is The lifetime was measured until it exceeded twice the starting torque.

  The foamed solid lubricant encapsulated bearing of the present invention is excellent in the lubrication performance of the solid lubricant that holds the lubricating oil, and can be operated even at high speed rotation with a long service life. Therefore, the stranded wire machine, electric equipment, printing machine, automobile parts It can be suitably used as a foamed solid lubricant encapsulated bearing for various industrial machines such as electrical accessories and construction machines.

It is a schematic diagram which shows the example of enclosure to the radial ball bearing (without a sealing member) which concerns on the other Example of this invention. It is a schematic diagram which shows the example of enclosure to the radial ball bearing (with a sealing member) which concerns on the other Example of this invention. It is a schematic diagram which shows the example of enclosure to the thrust ball bearing (no sealing member) which concerns on the other Example of this invention. It is a schematic diagram which shows use of a cylindrical jig | tool in FIG. It is sectional drawing of the deep groove ball bearing which concerns on one Example of this invention.

Explanation of symbols

1, 11 Radial ball bearing 2, 12, 22, 32 Inner ring 3, 13, 23, 33 Outer ring 4, 14, 24, 34 Ball (rolling element)
5 Iron plate 6, 16, 26 Mixture of foamed solid lubricant component 7 Bearing outer diameter 15, 35 Seal member 21 Thrust ball bearing 25 Mold 27 Cylindrical jig 28 Foamed solid lubricant 31 Deep groove ball bearing 36 Cage 37 Foamed solid lubricant Agent

Claims (13)

A foamed solid lubricant-enclosed bearing in which a foamed solid lubricant formed by foaming and curing a mixture containing a lubricant component, a resin component, a curing agent, and a foaming agent is enclosed in the bearing internal space,
A foamed solid lubricant-enclosed bearing, wherein the foamed solid lubricant has a foaming ratio of 1.1 times or more and less than 20 times and a foam molding shrinkage rate of 5% or less.   The foamed solid lubricant encapsulated in claim 1, wherein the foamed solid lubricant has an oil separation rate of 1% or more and 15% or less when a force of 80.3 gf is continuously applied for 5 hours. bearing.   The foamed solid lubricant-enclosed bearing according to claim 1 or 2, wherein the foamed solid lubricant has a tensile strength measured according to Japanese Industrial Standard K6400 of 50 kPa or more.   The foamed solid lubricant-enclosed bearing according to any one of claims 1 to 3, wherein the foamed solid lubricant has an open cell ratio of 50% or more. 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 having a hydroxyl group in the molecule. The liquid rubber has a polymer main chain composed of hydrocarbon, and a hydroxyl group having an amount of hydroxyl value of 25 to 110 mgKOH / g at the end of the main chain. A liquid rubber having
The curing agent is an organic compound having an isocyanate group in the molecule,
The blowing agent is water;
The ratio between 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 foam according to any one of claims 1 to 4, 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 entire mixture. Solid lubricant sealed bearing.   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 foamed solid lubricant encapsulated bearing according to claim 5, wherein:   The organic compound having an isocyanate group in the molecule is a prepolymer having two or more isocyanate groups in the molecule and an isocyanate group ratio of 2.5 to 5.0 NCO%, or an aromatic polyisocyanate. The foamed solid lubricant encapsulated bearing according to claim 5 or 6, The lubricating component is at least one lubricating component selected from lubricating oil and grease;
The resin component is a urethane prepolymer containing 2 wt% or more and less than 6 wt% of isocyanate groups in the molecule,
The blowing agent is water;
5. The mixture according to claim 1, wherein 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 50% or more. The foamed solid lubricant encapsulated bearing described.   The foamed solid lubricant according to claim 8, 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. Enclosed bearing.   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). A foamed solid lubricant encapsulated bearing according to claim 8 or 9.   9. The ratio of the hydroxyl group of water and 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). A foamed solid lubricant sealed bearing according to claim 9 or claim 10.   12. The foamed solid lubricant-enclosed bearing according to claim 8, wherein the curing agent is an aromatic polyamino compound.   A mixing step of mixing a component including a lubricating component, a resin component, a curing agent, and a foaming agent, a step of sealing the inside of the bearing before the mixture obtained by the mixing step is foam-cured, and the inside of the bearing after sealing A method for producing a foamed solid lubricant encapsulated bearing according to claim 5 or 8, further comprising a step of foaming and curing in a space.

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