JP2008297366A - Bearing holding foamed solid lubricant sealed therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing holding a foamed solid lubricant sealed therein which is excellent in lubricant retentivity, has a long life, can be operated even at a high speed rotation, can be made in relatively simple processes, can respond to the demand of cost reduction, and is excellent in heat resistance and durability. <P>SOLUTION: This bearing holding a foamed solid lubricant enclosed therein in which a foamed solid lubricant 37 is sealed in a bearing 31 is characterized in that the foamed solid lubricant 37 is produced by foaming and curing a mixture comprising a lubricating component, a liquid rubber whose polymer main chain comprises a hydrocarbon and which has hydroxyl groups at a hydroxyl group value of 25 to 110 mgKOH/g at the terminals of the main chain, a curing agent comprising an organic compound having isocyanate groups in the molecule, and the foaming agent; the equivalent ratio (OH/NCO) of the hydroxyl groups contained in the liquid rubber/the isocyanate groups contained in the curing agent is 1/(1.0 to 2.0); and the lubricating component and the liquid rubber are contained in amounts of 40 to 80 wt.% and 5 to 45 wt%, respectively, based on the total amount of the mixture. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a foamed solid lubricant-enclosed bearing in which a foamed solid lubricant is encapsulated.

  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, grease with increased lubricating oil and shape retention and liquid lubricant can be retained to prevent scattering and dripping. 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 the lubricating oil, which eliminates the need for maintenance to replenish the lubricating oil. It is intended to be useful for extending the life of bearings in environments and environments where strong inertial forces are applied.

In addition, the rolling bearing filled with the solid lubricant according to the above-described prior art cannot be used because the resin component as a base material melts due to short life, easy to seize at high speed rotation, and large heat generation. There is a drawback. In the full pack specification, the solid lubricant contracts in the process of cooling after solidifying the solid lubricant in the bearing, and the lubricant itself entraps the rolling elements, resulting in a large rotational torque. There is a problem that it is easy to become hot.
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.

Further, 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, there is no known solid foamed lubricant that has rubber elasticity that can be used at sites where external stress such as compression and bending acts, has high lubricant retention, and allows large deformation.
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 cope with such problems, and has an excellent lubricant holding power, can be operated at high speed with a long service life, and can relatively simplify the manufacturing process. An object of the present invention is to provide a foamed lubricant-enclosed bearing that can meet the demand for cost reduction.

  The foamed solid lubricant-enclosed bearing of the present invention is a foamed solid lubricant-enclosed bearing in which a foamed solid lubricant is enclosed inside the bearing, and the foamed solid lubricant has a lubricating component and a hydroxyl group in the molecule. A mixture comprising a liquid rubber, a curing agent, and a foaming agent is foamed and cured, and the lubricating component is at least one lubricating component selected from hydrocarbon-based lubricating oil and hydrocarbon-based grease, and the liquid The rubber is a liquid rubber having a polymer main chain composed of hydrocarbons and having hydroxyl groups in an amount such that the hydroxyl value is 25 to 110 mgKOH / g at the ends 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 ) = In the range of / (1.0-2.0), the mixture, with respect to the total mixture, the lubricating component 40-80% by weight, characterized in that it comprises the liquid rubber 5-45 wt%.

  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 polymer obtained by hydrogenating the diene polymer. It is characterized by being.

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 to 5.0 NCO%, or an aromatic polyisocyanate, In particular, it is tolylene diisocyanate.
The mixture containing the lubricating component, liquid rubber having a hydroxyl group in the molecule, a curing agent, and a foaming agent is foamed and cured at least after being encapsulated around the rolling elements.

  The foamed solid lubricant sealed bearing of the present invention is characterized in that the foamed solid lubricant is sealed inside a rolling bearing or a sliding bearing.

  The foamed solid lubricant-enclosed bearing of the present invention encloses the foamed solid lubricant inside the bearing (the space between the cage and the inner and outer rings, the space between the inner and outer rings in a rolling bearing without a cage, etc.). This foaming solid lubricant foams and cures a mixture containing a lubricating component, a hydrocarbon-based liquid rubber having a hydroxyl group in the molecule, a curing agent, and a foaming agent. Occluded inside. For this reason, the lubricant is gradually released from the foamed solid lubricant due to external stresses such as centrifugal force, compression, bending, and expansion accompanying the rotational movement of the bearing, and capillary action, allowing operation even at high speeds. Therefore, it has excellent lubricant retention, and can reduce the size, performance and life of the bearing.

The foamed solid lubricant also serves as a seal member against the entry of dust, moisture, etc. from the outside. In addition, since it has many porous portions, it is advantageous in terms of reducing the weight of the bearing.
In addition, since it is not necessary to enclose a lubricant after assembly, production efficiency is improved and manufacturing can be performed at low cost.

As a solid lubricant used in the solid foam lubricant encapsulated bearing of the present invention, as a result of intensive studies on a solid lubricant that has excellent lubricant retention and can suppress the amount of lubricating oil seepage, the lubricating component and intramolecular A foamed solid lubricant was obtained by foaming and curing a mixture containing a liquid rubber having a hydroxyl group, a curing agent, and a foaming agent. This foamed solid lubricant is a solid material obtained by foaming and curing a urethane resin composed of a liquid rubber having a hydroxyl group in the molecule and a curing agent, and the lubricating component is occluded inside the resin. This is a foamed solid lubricant. It should be noted that the lubricating component is occluded in the foamed / cured solid component when a liquid or semi-solid lubricating component such as a lubricating oil or grease described later has a hydroxyl group in the molecule in the foamed / cured solid component. It means that it does not react with the liquid rubber or curing agent it contains and does not become a compound.
This foamed solid lubricant has excellent holding power for lubricating oil, etc., and even if it is deformed by external force, it can suppress the amount of lubricating oil oozing out to the minimum necessary and can be manufactured at low cost, and can be enclosed only in the required part of the bearing, It was found that the bearing can be manufactured efficiently. The present invention is based on such knowledge.

In the solid foam lubricant encapsulated bearing of the present invention, the lubricating component is occluded in the liquid rubber of the encapsulated solid foam lubricant. Therefore, due to the flexibility of the liquid rubber, for example, by deformation due to external force such as compression, expansion, bending, and twisting. The lubricant can be exuded and released gradually from between the molecules of the liquid rubber. At this time, the amount of 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 liquid rubber or the like. 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 foamed / cured solid component (liquid rubber) without becoming a compound. Say.
Further, in the foamed solid lubricant used in the bearing of the present invention, the liquid rubber has a large surface area due to foaming, and the excess lubricating oil that has oozed out can be temporarily held in the foam bubbles again. The amount of lubricating oil that oozes out is stable, and the amount of lubricating oil retained is greater than that in a non-foamed state by occluding the lubricant in the liquid rubber and impregnating the bubbles.

In addition, the foamed solid lubricant used in the bearing of the present invention requires very little energy when bent compared to a non-foamed body, and can be flexibly deformed while retaining the lubricating oil at a high density. Therefore, in the process of solidifying the foamed solid lubricant and cooling it, even if the foamed 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, no special equipment is required because the mixture containing the lubricating component, the liquid rubber having a hydroxyl group in the molecule, the curing agent, and the foaming agent is only foamed and cured. Can be molded.
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 solid component used in the foamed solid lubricant used in the bearing of 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, and this 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 end 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.

Examples of the curing agent that can be used in the present invention include organic compounds having an isocyanate group in the molecule, and are particularly limited as long as the isocyanate compound reacts with a hydroxyl group in the liquid rubber to extend the molecular chain or crosslink. Can be used without 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. And diisocyanate.
Examples of 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 or the like 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 a ratio of isocyanate groups of 2.5 to 5.0 NCO% can be used. In addition, NCO% is the weight% of the NCO group in a prepolymer. A 2.5 to 5.0 NCO% prepolymer can react with a hydroxyl-terminated polydiene polymer and 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 Polyurethane) in the PPG system, and Coronate 4090 (manufactured by Nippon Polyurethane Co., Ltd.) in the PTMG system. Examples of the ester type include Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.), and caprolactone type includes Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes), and Sianaprene 7-QM. (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 greater than 1 / 1.0, the isocyanate group to be crosslinked is insufficient, and curing is not sufficient. Further, when (OH / NCO) is smaller than 1 / 2.0, the isocyanate group is excessive, so that the crosslink density increases, rubber elasticity decreases, and deformation may not be allowed.

  As the foaming agent, which is a means for foaming the foamed solid lubricant used in the bearing of the present invention, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas because an isocyanate compound is used as a raw material.

  Moreover, when using foaming with such a reaction, it is preferable to use a catalyst as needed. For example, a tertiary amine catalyst or an organometallic catalyst 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 lubricating component that can be used in the present invention can be used as long as it does not dissolve the solid component forming 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 grease is obtained by adding a base oil to a hydrocarbon oil and adding a thickener, and examples of the base oil include the above-described hydrocarbon lubricants. 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, for example, by reaction of diisocyanate and monoamine. Diisocyanates include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, and monoamines include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, p-Toluidine, cyclohexylamine and the like can be mentioned. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those used for the production of diurea compounds. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, xylenediamine, and the like. Is mentioned.

  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. As oil components that may be used by mixing oil with these waxes, the same oil components as those described above can be used.

The foamed solid lubricant to be sealed in the bearing of the present invention is obtained by foaming and curing a mixture containing the lubricating component, liquid rubber, curing agent, and foaming agent.
The blending ratio of the lubricating component is 40% by weight to 80% by weight with respect to 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.

  The blending ratio of the curing agent is determined depending on the blending amount of the liquid rubber and the foaming ratio, and the blending ratio of the foaming agent is determined in relation to the foaming ratio described later. That is, the amount of the curing agent is determined by the relationship between the hydroxyl equivalent of the liquid rubber and the equivalent of water.

  The expansion ratio of the foamed solid lubricant used in the bearing of the present invention is preferably 1.1 times to 50 times, and more preferably 1.1 times to 10 times. When the expansion ratio is less than 1.1 times, the bubble volume is small and deformation is not allowed when external stress is applied. Further, since the foamed solid lubricant is too hard, there is a problem that the deformation following the external stress cannot be made. Also, if the expansion ratio exceeds 50 times, it will be difficult to obtain the strength to withstand external stress, which may lead to breakage or destruction.

In the foamed solid lubricant used in the bearing of the present invention, the method of mixing the component containing the lubricating component, the liquid rubber having a hydroxyl group in the molecule, the curing agent, and the foaming agent is not particularly limited. Mixing can be performed using a generally used stirrer such as a Henschel mixer, a ribbon mixer, a juicer mixer, or a mixing head.
Since the obtained mixture is fluid before foaming and curing, it can be easily filled into any part in a bearing having a complicated shape.

  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 be 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 present invention, various additives such as pigments, antistatic agents, flame retardants, antifungal agents and fillers can be added to the foamed solid lubricant as necessary.
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

In the present invention, using 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, in order to simultaneously achieve a high filling of the lubricating component and a high elongation of material properties at the same time. desirable. 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.

  In the present invention, the bubbles generated when the liquid rubber having a hydroxyl group in the molecule is made porous by foaming are preferably continuous cells in which the bubbles communicate. This is because the lubricating component is directly supplied from the surface of the resin to the outside through open cells by external stress. In the case of closed cells where the bubbles do not communicate with each other, the entire amount of lubricating oil in the solid component is temporarily isolated in the closed cells, making it difficult to move between the bubbles, and may not be sufficiently supplied to the outside when necessary. is there.

The foamed solid lubricant may be foamed and cured after pouring the above mixture around at least the rolling elements in the bearing, and then post-processed to the desired shape by cutting and grinding after foaming and curing at normal pressure It can also be incorporated in the bearing.
In addition, since the foamed solid lubricant is flexible, the rotational torque is hardly increased even in the full pack specification, and heat generation can be suppressed. It also serves as a seal against the entry of dust and moisture from the outside.
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.
When used in a slide bearing, the function as a slide bearing can be exhibited by using it by sealing between an inner ring and an outer ring or by using it as a lubricant supply member adjacent to a sintered metal.

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 holds 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. And a seal member 35 fixed to the outer ring 33 and the like. The foamed solid lubricant 37 is sealed around at least the rolling element 34.

An example of the plain bearing of the present invention will be described with reference to FIGS. FIG. 6 is a perspective view showing a drive unit of a printer using a slide bearing according to another embodiment of the present invention, and FIG. 7 is a cross-sectional view of the slide bearing in FIG.
As shown in FIG. 6, the drive unit of the printer includes a shaft 42, a slide bearing 44, and a carriage 41 that is supported by the slide bearing 44 and moves linearly on the shaft 42.
As shown in FIGS. 7A and 7B, the sliding bearing 44 includes the sintered metal porous body 45 that slides on the shaft 42, and the above-described foaming at a portion adjacent to the sintered metal porous body 45. The solid lubricant 46 is provided and is slidably guided on the sliding surface 43 (the outer peripheral surface of the shaft 42).

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 facing down. 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 or the like is further formed on the bearing 11. 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.
The lubricating components, liquid rubber, curing agent, foaming agent and catalyst used in the examples and comparative examples 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): 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 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 (4.4NCO% made by Nippon Polyurethane)
Elastomer 2 (UE2): Plaxel EP1130 (3.3NCO% manufactured by Daicel Chemical Industries)
Foaming agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (catalyst) DM70 (manufactured by Tosoh Corporation)

Examples 1 to 15
In the polytetrafluoroethylene resin container (diameter 70 mm × height 150 mm), the blending materials excluding the curing agent were mixed well in 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 internal space of the ball bearing 6204 (made by NTN). 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. The actual machine durability test shown below was performed using this test piece, and the durability in the actual machine was evaluated.

<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.

Comparative Examples 1 to 4
In the same manner as in Examples 1 to 15 described above, the compounding materials excluding the curing agent were mixed well at the blending ratio shown in Table 3, and after adding and mixing the curing agent, the interior space of the ball bearing 6204 was filled. In Comparative Example 1, oil and resin separated and could not be cured well. Moreover, in Comparative Example 2 and Comparative Example 3, it did not harden but remained liquid. In Comparative Example 4, there was almost no release of lubricating oil, and the effectiveness as a lubricant was not exhibited. The results are also shown in Table 3.

Comparative Example 5
The ball bearing 6204 was sealed with a two-component polyurethane flexible foam (NEF-337 / CEF-268, manufactured by Nippon Polyurethane Co., Ltd.) and then impregnated with a lubricating oil so as to have the composition shown in Table 3. An actual machine durability test was performed under the same conditions as in Example 1. However, excessive release of the lubricating components occurred, and the effect as a solid lubricant was not exhibited. The results are also shown in Table 3.

  The foamed solid lubricant-enclosed bearing of the present invention has excellent lubricant retention, can be operated even at high speeds and has a long service life. Therefore, stranded wire machines, electric equipment, printing machines, automobile parts, electrical equipment, construction machinery It can be suitably used as a foamed solid lubricant encapsulated bearing used in various industrial machines such as automobiles, particularly as a foamed solid lubricant encapsulated bearing used in automotive electrical equipment and auxiliary equipment.

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. It is a perspective view which shows the drive part of the printer using the slide bearing which concerns on the other Example of this invention. It is sectional drawing of the slide bearing in FIG.

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 41 Carriage 42 Shaft 43 Sliding surface 44 Slide bearing 45 Sintered metal porous body 46 Foamed solid lubricant

Claims (8)

A foamed solid lubricant sealed bearing in which a foamed solid lubricant is sealed inside the bearing,
The foamed solid lubricant is obtained by foaming and curing a mixture containing a lubricating component, a liquid rubber having a hydroxyl group in the molecule, a curing agent, and a foaming agent.
The lubricating component is at least one lubricating component selected from a hydrocarbon-based lubricating oil and a hydrocarbon-based grease;
The liquid rubber 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 of the main chain ends is 25 to 110 mgKOH / g.
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). ,
A foamed solid lubricant-enclosed bearing, 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 3500 having a hydroxyl group at the main chain end of a polymer of butadiene or isoprene, or a modified hydroxyl group-terminated diene polymer obtained by hydrogenating the diene polymer. The foamed solid lubricant-enclosed bearing according to claim 1, 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 foamed solid lubricant encapsulated bearing according to claim 2.   3. The foamed solid lubricant encapsulated bearing according to claim 1, wherein the organic compound having an isocyanate group in the molecule is an aromatic polyisocyanate.   5. The foamed solid lubricant encapsulated bearing according to claim 4, wherein the aromatic polyisocyanate is tolylene diisocyanate.   6. The foamed solid lubricant encapsulated bearing according to claim 1, wherein the mixture is encapsulated at least around a rolling element and then foamed and cured.   The foamed solid lubricant sealed bearing according to any one of claims 1 to 6, wherein the bearing is a rolling bearing.   The foamed solid lubricant encapsulated bearing according to any one of claims 1 to 5, wherein the bearing is a sliding bearing.

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