JP4887127B2 - Foamed lubricant encapsulated bearing - Google Patents

Description

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

  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, there is a solid lubricant in which ultra-high molecular weight polyolefin or urethane resin and its curing agent are mixed with lubricating oil and 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 provided in the vicinity of a friction contact portion inside the bearing (see Patent Document 5).

  These solid lubricants, when sealed in a bearing and solidified, 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.

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 disadvantage that it can not. In the full pack specification, the solid lubricant shrinks in the process of cooling after solidifying the solid lubricant in the bearing, and the lubricant itself entraps the rolling elements, increasing the rotational torque. There is a problem that it is easy to generate heat.
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

  The present invention has been made in order to cope with such problems, and has excellent lubricant holding power, can be operated even at high speed rotation with a long service life, and can 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 lubricant-enclosed bearing of the present invention is a foamed lubricant-enclosed bearing in which a foamed lubricant is enclosed inside the bearing, and the foamed lubricant includes a urethane prepolymer having an isocyanate group in the molecule, and a curing agent. And a foaming agent is foamed and cured, and the blending ratio of the lubricating component is 1% to 90% by weight with respect to the whole mixture.
The foamed lubricant-enclosed bearing is a rolling bearing.

The foamed lubricant has an open cell ratio of 50% or more.
Further, the curing agent is an aromatic polyamine compound, and the foaming agent is water.
Further, the mixture is filled around the rolling elements before foaming / curing is completed.

The foamed lubricant-enclosed bearing of the present invention is used by encapsulating the foamed 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 lubricant is formed by foaming and curing a mixture containing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent. Occluded. For this reason, the lubricating oil is gradually released from the foamed lubricant due to external stresses such as centrifugal force, compression, bending, expansion, and capillary action associated with the rotational movement of the bearing, and capillary action. Miniaturization, high performance and long life of the bearing can be achieved. The fact that the lubricating component is occluded in the foamed / cured solid component means that a liquid / semi-solid lubricating component such as a lubricating oil or grease described later is a urethane prepolymer or cured in the foamed / cured solid component. It means to be contained without reacting with the agent and without becoming a compound.
Further, by encapsulating the foamed 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.
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 result of intensive studies on solid lubricants that have excellent lubricant retention as the solid lubricant used in the foamed lubricant encapsulated bearing of the present invention and can suppress the amount of lubricating oil oozing out, the lubricating component and isocyanate group in the molecule A foamed lubricant was obtained by foaming / curing a mixture containing a urethane prepolymer having a curing agent, a curing agent, and a foaming agent. This foamed lubricant is a solid material in which a urethane prepolymer is made porous by foaming and curing, and is a foamed lubricant formed by occluding a lubricating component in the resin.
This foaming lubricant has excellent holding power for lubricating oil, etc., and even if it is deformed by external force, it can minimize the amount of lubricating oil leaked out, can be manufactured at low cost, can be sealed only at the necessary part of the bearing, It turned out that it can manufacture efficiently. The present invention is based on such knowledge.

The foamed lubricant used in the foamed lubricant encapsulated bearing of the present invention absorbs a lubricating component in the resin, so that the lubricant is soaked by the flexibility of the resin, for example, by deformation due to external force such as compression, expansion, bending, and twisting. And can be released gradually from between the resin molecules. 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 the resin.
Further, in the foamed 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 held in the foam bubbles again and ooze out. The amount of oil is stable, and by retaining the lubricant in the resin and impregnating the bubbles, the retained amount of the lubricant is increased as compared with the non-foamed state.

In addition, the foamed lubricant used in the present invention requires very little energy when bent compared to non-foamed materials, and can be flexibly deformed while retaining the lubricating oil at a high density. Therefore, in the process of cooling after solidifying the foamed lubricant, even if the foamed lubricant contracts and embraces the rolling element, it can be easily deformed because the energy required for bending and deformation is small, and rotation The problem that the torque becomes large can be prevented. Moreover, since it has many foamed parts, ie, a porous part, it is advantageous also at the point of weight reduction.
Also, since it is only necessary to foam and cure a mixture containing a lubricating component, a urethane prepolymer, a curing agent, and a foaming agent, no special equipment is required, and it can be filled and molded in any place. Is possible.
Further, the density of the foaming lubricant can be changed by controlling the blending amount of the mixture containing the lubricating component, the urethane prepolymer, the curing agent, and the foaming agent.

  The urethane prepolymer used in the present invention is a urethane prepolymer having an isocyanate group in the molecule, and this isocyanate group may be blocked by another substituent. The isocyanate group contained in the molecule may be at the end of the molecular chain or may be contained at the end of the side chain branched from the molecular chain. The urethane prepolymer may have a urethane bond in the molecular chain.

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

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

  Examples of polyester polyols include polyester polyols, polycaprolactone polyols, and polyether ester polyols. Polyester polyols are carboxylic acids (aliphatic saturated or unsaturated carboxylic acids such as adipic acid, azelaic acid, dodecanoic acid, maleic acid, fumaric acid, itaconic acid, dimerized linoleic acid and / or aromatic carboxylic acids such as phthalic acid. , Isophthalic acid) and a polyol (the above low molecular polyol and / or polyether polyol).

Polycaprolactone polyol is a polymerization initiator for glycols and triols such as ε-caprolactone, α-methyl-ε-caprolactone, ε-methyl-ε-caprolactone, etc. as organometallic compounds, metal chelate compounds, fatty acid metal acylates, etc. Obtained by addition polymerization in the presence of a catalyst. The polyether ester polyol is obtained by subjecting a polyester having a carboxyl group and / or an OH group to an addition reaction of an alkylene oxide such as ethylene oxide or propylene oxide. As the castor oil-based polyol, castor oil and castor oil or castor oil fatty acid and the above low molecular polyol, polyether polyol, and polyester polyol are transesterified or esterified polyol.
The urethane prepolymer used in the present invention preferably has an isocyanate group (—NCO) content of 2% by weight or more. If the isocyanate group (-NCO) content is less than this, it becomes difficult to achieve both foamability and elasticity.

Polyisocyanates include aromatic diisocyanates, aliphatic or alicyclic and polyisocyanate compounds.
Aromatic diisocyanates include, for example, diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and mixtures thereof, 1,5-naphthylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate Is mentioned.
Aliphatic or alicyclic diisocyanates include, for example, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 1,3-cyclobutane diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isopropane diisocyanate. 2,4-hexahydrotoluylene diisocyanate, 2,6-hexahydrotoluylene diisocyanate, 1,3-hexahydrophenyl diisocyanate, 1,4-hexahydrophenyl diisocyanate, 2,4′perhydrodiphenylmethane diisocyanate, 4, 4'-perhydrodiphenylmethane diisocyanate is mentioned.
Examples of the polyisocyanate compound include 4,4 ′, 4 ″ -triphenylmethane triisocyanate, 4,6,4′-diphenyl triisocyanate, 2,4,4′-diphenyl ether triisocyanate, and polymethylene polyphenyl polyisocyanate. It is done.
Moreover, what modified | denatured some of these isocyanate to biuret, allophanate, carbodiimide, oxazolidone, amide, imide, etc. is mentioned.

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

  Examples of commercially available urethane prepolymers that can be suitably used in the present invention include trade name Plaxel EP manufactured by Daicel Chemical Industries, and trade names Coronate 4090 and 4047 manufactured by Nippon Polyurethane. Plaxel EP is a white solid urethane prepolymer having a melting point above room temperature.

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

The blending ratio of the urethane prepolymer having an isocyanate group and the curing agent having a terminal hydroxyl group or a terminal amine group is an equivalent ratio of the hydroxyl group (—OH) or amine group (—NH ₂ ) to the isocyanate group (—NCO). preferably in the range of (OH or NH ₂ /NCO)=1/(0.9~1.7), especially considering the foaming and elasticity, (OH or NH ₂ /NCO)=1/(1.0 ~ 1.5) is preferred.

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

The foaming agent that can be used in the present invention can be used as long as it can foam the urethane prepolymer. Examples of the foaming agent include (a) a chemical foaming agent such as water that reacts with an isocyanate compound to generate carbon dioxide gas, and (b) azobisiso that generates nitrogen gas by chemical decomposition by heat treatment or light irradiation. Decomposable foaming agents such as butyronitrile (AIBN) and azodicarbonamide (ADCA), (c) a physical foaming agent that heats and vaporizes a relatively low boiling organic solvent such as acetone and hexane, and (d) nitrogen. And a mechanical foaming agent that blows an inert gas or air from the outside.
In this invention, since the urethane prepolymer which has an isocyanate group in a molecule | numerator is used, the water which reacts with an isocyanate compound and generate | occur | produces a carbon dioxide gas is preferable.

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

The lubricating component that can be used in the present invention can be used regardless of the type as long as it does not dissolve the solid component forming the foam. As the lubricating component, for example, lubricating oil, grease, wax or the like can be used alone or in combination.
Examples of the lubricating oil include paraffinic and naphthenic mineral oils, ester synthetic oils, ether synthetic oils, hydrocarbon synthetic oils, GTL base oils, fluorine oils, and silicone oils. These can be used alone or as a mixed oil.

The grease is obtained by adding a thickener to a base oil, and examples of the base oil include the above-described lubricating oil.
Examples of the thickener include soaps such as lithium soap, lithium complex soap, calcium soap, calcium complex soap, aluminum soap, aluminum complex soap, and urea-based compounds such as diurea compounds and polyurea compounds, but are particularly limited. It is not a thing.
A diurea compound is obtained by reaction of diisocyanate and a monoamine, for example. Examples of diisocyanates include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, hexane diisocyanate, and monoamines include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, Examples include p-toluidine, cyclohexylamine and the like. The polyurea compound can be obtained, for example, by reacting diisocyanate with a monoamine or diamine. Examples of the diisocyanate and monoamine include those similar to those used for the production of the diurea compound. Examples of the diamine include ethylenediamine, propanediamine, butanediamine, hexanediamine, octanediamine, phenylenediamine, tolylenediamine, and xylenediamine. Is mentioned.

  The blending ratio of the base oil in the grease is 1 to 98% by weight, preferably 5 to 95% by weight, based on the whole grease component. If the base oil is less than 1% by weight, it will be difficult to sufficiently supply the lubricating oil to the necessary locations. On the other hand, when it is more than 98% by weight, it remains liquid without being hardened with grease even at low temperatures.

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

  Lubricating components further include solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, oily agents such as amines, fatty acids and fats, antioxidants such as amines and phenolic compounds, petroleum sulfonates. Rust inhibitors such as dinonyl naphthalene sulfonate and sorbitan esters, extreme pressure agents such as sulfur and sulfur-phosphorus compounds, antiwear agents such as organic zinc and phosphorus compounds, metals such as benzotriazole and sodium nitrite Various additives such as viscosity index improvers such as an inert agent, polymethacrylate, and polystyrene may be included.

The foaming lubricant used in the present invention is obtained by foaming and curing a mixture containing the above-described lubricating component, urethane prepolymer, curing agent, and foaming agent.
The blending ratio of the lubricating component is 1 to 90% by weight, preferably 5 to 80% by weight, based on the entire mixture. If the lubrication component is less than 1% by weight, the supply amount of the lubrication component is small and a sufficient life cannot be obtained, or the friction coefficient increases due to lack of lubricant, which causes wear. When it exceeds 90% by weight, it does not solidify.
The blending ratio of the urethane prepolymer having an isocyanate group in the molecule is 8 to 98% by weight, preferably 20 to 80% by weight, based on the entire mixture. When it is less than 8% by weight, it does not solidify, and when it is more than 98% by weight, the supply amount of the lubricating component is small and a sufficient life cannot be obtained.

  The blending ratio of the curing agent is determined by the blending amount of the urethane prepolymer 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 (ratio) of the curing agent is determined by the relationship between the hydroxyl equivalent of the urethane prepolymer having an isocyanate group in the molecule and the equivalent of water.

A method of mixing the component including the lubricating component, the urethane prepolymer, the curing agent, and the foaming agent is not particularly limited, and a commonly used stirring such as a Henschel mixer, a ribbon mixer, a juicer mixer, a mixing head, or the like. Can be mixed using the machine. 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 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, 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 achieve both high filling of the lubricating component and high strength 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 increase in strength 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, it is preferable that the bubbles generated when the urethane prepolymer is made porous by foaming are open cells that communicate with each other. 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 open cell ratio of the foamed lubricant used in the present invention is preferably 50% or more, more preferably 70% or more. When the open cell ratio is less than 50%, the ratio of the resin component (solid component) lubricating oil temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary.

The open cell ratio of the foamed lubricant used in the present invention can be calculated by the following procedure.
(1) The foamed and hardened foamed lubricant is cut into an appropriate size to obtain Sample A. The weight of sample A is measured.
(2) Soxhlet A is washed for 3 hours (solvent: petroleum benzine). 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 the release of the lubricating component.

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

The foamed lubricant may be foamed and cured after pouring the above mixture into the bearing, and after foaming and curing at normal pressure, it is post-processed into the desired shape by cutting or grinding, and incorporated into the bearing. You can also.
In addition, since the foamed lubricant is flexible, the rotational torque is not easily increased even in the full pack specification, and heat generation can be suppressed. It also serves as a seal against entry of dust, moisture, etc. 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 foam 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 foamed lubricant encapsulated bearing of 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. A foamed lubricant 37 is sealed at least around the rolling element 34.

An example of a method for enclosing the foamed 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. A well-stirred mixture 6 of the foamed lubricant component immediately before foaming is poured into a space surrounded by the inner ring 2, the outer ring 3, and the iron plate 5, and is 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 ratio of the foamed lubricant in the bearing is improved. After completion of foaming and curing of the mixture 6, the iron plate 5 or a similar jig is removed to obtain a foamed lubricant-enclosed 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 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 ratio of the foaming 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 a similar treatment is further formed on the upper portion of the bearing 11. It may be covered with ingredients. 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 foamed 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 hardened to become the foamed lubricant 28, the mold 25 and the cylindrical jig 27 are removed to obtain a foamed 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 lubricant component mixed in the screw is sealed into the bearing from the nozzle.

  In the foamed lubricant encapsulated bearing of the present invention, the lubricating component contained in the foamed lubricant impregnated does not ooze out due to deformation of the foam due to external force, and the lubricating component is efficiently slid It can be used by oozing out. 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 1 to 5
In a polytetrafluoroethylene resin beaker (diameter 60 mm × height 150 mm) at 80 ° C., the blending materials excluding the curing agent, amine catalyst and foaming agent were mixed well at the blending ratio shown in Table 1. Next, MOCA (curing agent) manufactured by Ihara Chemical Co., Ltd. dissolved at 120 ° C. was put into the beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. This mixture was filled in the internal space of the ball bearing 6204. After a few seconds, the foaming reaction started and allowed to stand at room temperature for curing to obtain a test piece of foamed lubricant encapsulated bearing. Using this test piece, the following actual machine durability test was performed to evaluate the durability of the actual machine. Further, the open cell ratio of the foamed lubricant was measured based on the above-described method for calculating the open cell ratio. The results are also shown in Table 1.

Comparative Example 1
After foaming and curing without using a lubricating oil, a test piece of a post-impregnated foamed lubricant-enclosed bearing was obtained in the same manner as in Example 1 except that the lubricating oil was post-impregnated. Using this test piece, the following actual machine durability test was performed to evaluate the durability of the actual machine. Further, the open cell ratio of the foamed lubricant was measured based on the above-described method for calculating the open cell ratio. The results are also shown in Table 1.

<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 Measure the lifetime until the torque exceeds twice the starting torque.

  As shown in Table 1, Examples 1 to 5 can maintain good lubricity even at high temperatures.

  The foamed lubricant-enclosed bearing of the present invention has excellent lubricant retention, can be operated even at high speeds and has a long service life. Thus, stranded wire machines, electric equipment, printing machines, automobile parts, electrical accessories, construction machinery, etc. The present invention can be suitably used as a foamed lubricant encapsulated bearing for use in various industrial machines, especially as a foamed lubricant encapsulated bearing for use in automobile electrical equipment and accessories.

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 lubricant components 7 Bearing outer diameter 15, 35 Seal member 21 Thrust ball bearing 25 Mold 27 Cylindrical jig 28 Foamed lubricant 31 Deep groove ball bearing 36 Cage 37 Foamed lubricant

Claims (4)

A foamed lubricant encapsulated bearing in which a foamed lubricant is enclosed inside the bearing,
The foaming lubricant is obtained by foaming and curing a mixture containing a lubricating component, a urethane prepolymer having an isocyanate group in the molecule , an aromatic polyamine compound as a curing agent , and water as a foaming agent,
The blending ratio of the lubricating component is 1% to 90% by weight with respect to the whole mixture, and the foamed lubricant-enclosed bearing is characterized in that:   The foamed lubricant-enclosed bearing according to claim 1, wherein the mixture is filled around a rolling element before foaming / curing is completed. The foamed lubricant-enclosed bearing according to claim 1 or 2, wherein an open cell ratio of the foamed lubricant is 50% or more. The foamed lubricant-enclosed bearing according to any one of claims 1 to 3 , wherein the foamed lubricant-enclosed bearing is a rolling bearing.

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