JP2008297368A - 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 by relatively simple processes, and thus can respond to the demand of cost reduction. <P>SOLUTION: This bearing holding a foamed solid lubricant sealed 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 urethane prepolymer having isocyanate groups in the molecule, a curing agent, and a foaming agent; the lubricating component is at least one of hydrocarbon-based lubricants and hydrocarbon-based greases; the urethane prepolymer has an isocyanate group content of ≥2 wt.% to <6 wt%; the foaming agent is water; the lubricating component is contained in an amount of 30 to 70 wt.% based on the total amount of the mixture; and an open-cell rate is ≥50%, after foamed. <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, 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 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 even in environments where the environment is subject to strong inertia.

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 shrinks 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 retention force, can be operated at a high service life with a long service life, and can relatively simplify the manufacturing process. An object of the present invention is to provide a foamed solid lubricant sealed 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 an isocyanate group in the molecule. A mixture containing a urethane prepolymer, a curing agent, and a foaming agent is foamed and cured, and the lubricating component is at least one lubricating component selected from lubricating oil and grease, and the urethane prepolymer is an isocyanate. The group content is 2% by weight or more and less than 6% by weight, the blowing agent is water, and the mixture contains 30 to 70% by weight of the lubricating component with respect to the whole mixture, and the open cell ratio after foaming Is more than 50%.
The urethane prepolymer having an isocyanate group in the molecule is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.

In the foamed solid lubricant, the ratio of the isocyanate group contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of curing agent / NCO) = 1 / (1.1- 2.5).
Further, the ratio of the hydroxyl group of water as a blowing agent 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). And

In the foamed solid lubricant, the curing agent is an aromatic polyamino compound. In particular, the aromatic polyamino compound is an aromatic polyamino compound having a substituent at the position adjacent to the amino group.
In the foamed solid lubricant, the mixture comprising the lubricating component, the urethane prepolymer, the curing agent, and the foaming agent is foamed and cured at least after being encapsulated around the rolling elements. Features.

  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 foamed solid lubricant is obtained 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 in the ingredients. For this reason, the lubricant is gradually released from the foamed solid lubricant due to external forces such as centrifugal force, compression, bending, expansion, and capillary action associated with the rotational movement of the bearing, and capillary action. The bearing can be made smaller, higher performance and longer life. 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 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.
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 solid lubricant encapsulated bearing of the present invention and can suppress the amount of lubricating oil oozing out to the necessary minimum, the lubricating component and the molecule A foamed solid lubricant was obtained by foaming and curing a mixture containing a urethane prepolymer having an isocyanate group, a curing agent, and a foaming agent. This foamed solid lubricant is a solid material in which a urethane prepolymer is made porous by foaming and curing, and is a foamed solid lubricant in which a lubricating component is occluded inside the resin.
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.

The foamed solid lubricant used in the foamed solid lubricant-enclosed bearing of the present invention occludes a lubricating component in the resin, so that the lubricant is deformed by an external force such as compression, expansion, bending, and torsion due to the flexibility of the resin. Can be gradually 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 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.
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 foamed solid 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 solid component used in the foamed solid lubricant used in the bearing of the present invention is a urethane prepolymer that is excellent in heat resistance and flexibility and can be reduced in cost.
The urethane prepolymer that can be used in the present invention is obtained by a reaction between a compound having an active hydrogen group and a polyisocyanate, and the isocyanate group is contained at the end of the molecular chain or at the end of the side chain branched from within the molecular chain. It may be. The urethane prepolymer may have a urethane bond in the molecular chain.
Urethane prepolymers are classified into caprolactone-based, ester-based, ether-based, etc., depending on the type of monomer (= compound having an active hydrogen group) that reacts. There are Takenate L-1170 (manufactured by Mitsui Chemicals Polyurethanes), L-1158 (manufactured by Mitsui Chemicals Polyurethanes), and Coronate 4090 (manufactured by Nippon Polyurethanes) as ethers. Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemical Polyurethane Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemical Polyurethane Co., Ltd.), and Sianaprene 7-QM are used as the caprolactone system. (Manufactured by Mitsui Chemicals Polyurethane), Plaxel EP1130 (manufactured by Daicel Chemical Industries) and the like.
In addition, oligomers or prepolymer compounds whose terminal groups are modified to isocyanate groups 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 (manufactured by Idemitsu Kosan Co., Ltd.) and poly-bd HTP9 (manufactured by Idemitsu Kosan Co., Ltd.) can be mentioned as isocyanate-modified products of hydroxyl-terminated polybutadiene.
These urethane prepolymers can be used in a mixture of two or more depending on the intended mechanical properties.

In the present invention, 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 impact 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 present invention, it is considered that the reactivity of the amino group is suppressed by the substituent at the adjacent position because it undergoes a step of curing together with foaming.

  When the urethane prepolymer is cured with a polyamino compound, a foamable solid lubricant having urethane and urea bonds in the molecule is obtained. 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. Of the polyol compounds, trimethylolpropane is preferred.

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).
Foaming ratio of foamable solid lubricant in proportion of isocyanate group contained in urethane prepolymer, amino group (—NH ₂ ) or hydroxyl group (—OH) of curing agent, and hydroxyl group (—OH) of water as foaming agent And 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 foamable solid lubricant are remarkably lowered, but also the urethane elastomer may not be cured.

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. 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.
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. Moreover, ester synthetic oil, ether synthetic oil, fluorine oil, silicone oil and the like can be mentioned. 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. Similarly, greases based on ester-based synthetic oils, ether-based synthetic oils, fluorine oils, silicone oils and the like can also be used.
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 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. 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.

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, 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.

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

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

In the foamed solid lubricant used in the bearing of the present invention, the method of mixing the components including the lubricating component, the urethane prepolymer, the curing agent, and the foaming agent is not particularly limited. For example, a Henschel mixer, a ribbon mixer Mixing can be performed using a generally used stirrer such as 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.
In addition, since the mixture is quickly cured by the curing agent and the foaming agent, it is desirable that the curing agent and other components other than the foaming agent are mixed in advance, and finally the curing agent and the foaming agent are added.

  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, 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.

  In the present invention, the open cell ratio of the foamed solid lubricant after foaming is 50% or more. More preferably, it is 50% or more and 90% or less. When the open cell ratio is less than 50%, the ratio of the resin component (solid component) lubricating oil temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary. If it exceeds 90%, the strength of the foam itself tends to decrease, and the retention of the lubricating component decreases, so that the release of the lubricating component increases, which is disadvantageous for long-term use.

The open cell ratio of the foamed solid lubricant of the present invention 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.

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.

  The expansion ratio of the foamed solid lubricant used in the present invention is preferably 1.1 times to 100 times. More preferably, it is 1.1 times to 10 times. This is because if the expansion ratio is less than 1.1 times, the volume of the bubbles is small and deformation is not allowed when external stress is applied, or the foamed solid lubricant is too hard and cannot deform 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 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 or 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 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 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 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 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.
Lubricating components, urethane prepolymers, curing agents, foaming agents, and catalysts used in Examples and Comparative Examples 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): Pyronock Universal N6C (manufactured by Nippon Oil Corporation)
Urethane prepolymer Caprolactan-based urethane prepolymer 1 (prepolymer 1): Plaxel EP1130 (NCO 3.3%, manufactured by Daicel Chemical Industries)
Ether-based urethane prepolymer (Prepolymer 2): Coronate 4090 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Ester urethane prepolymer (Prepolymer 3): Coronate 4047 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Caprolactan urethane prepolymer (Prepolymer 4): Takenate L-1350 (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 5): Takenate L-1170 (NCO 2.4%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 6): Takenate L-1680 (NCO 3.2%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 7): Cyanaprene 7-QM (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 8): Takenate L-1158 (NCO 4.4%, manufactured by Mitsui Chemicals Polyurethanes)
Hardener MOCA (MOCA): Iharacamine MT (manufactured by Ihara Chemical)
Trimethylene-bis- (4-aminobenzoate) (CUA-4): CUA-4 (manufactured by Ihara Chemical)
Mixture of bis (methylthio) -2,4-toluenediamine, bis (methylthio) -2,6-toluenediamine and methylthiotoluenediamine (Etacure 300): Etacure 300 (manufactured by Albemarle)
Trimethylolpropane: Reagent blowing agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (catalyst) DM70 (manufactured by Tosoh Corporation)

Examples 1, 2, 5, 6, 8, 10-14, 16, 17, Comparative Examples 2, 3
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well in the blending ratios shown in Tables 1 to 3. Next, MOCA dissolved at 120 ° C. was put into a beaker and well stirred. Subsequently, an amine catalyst and a blowing agent were added and stirred. In Comparative Example 3, no foam stabilizer was used. 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 100 ° C. for 30 minutes to cure to obtain a foamed solid lubricant-enclosed bearing. Using this test piece, the following actual machine durability test was performed to evaluate the durability of the actual machine. The results are shown in Tables 1 to 3.
Further, the open cell ratio of the foamed solid lubricant was measured based on the above-described method for calculating the open cell ratio. The results are shown in Tables 1 to 3.

<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.

Example 3
In a polytetrafluoroethylene beaker (diameter: 70 mm × height: 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well at the blending ratio shown in Table 1. Next, trimethylene-bis (4-aminobenzoate) dissolved at 140 ° C. was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. 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 100 ° C. for 30 minutes to cure to obtain a foamed solid lubricant-enclosed bearing. Using this test piece, the above-mentioned actual machine durability test was performed, and the durability in the actual machine was evaluated. The results are also shown in Table 1.
Further, the open cell ratio of the foamed solid lubricant was measured based on the above-described method for calculating the open cell ratio. The results are also shown in Table 1.

Examples 4, 7, 9, 15
In a polytetrafluoroethylene beaker (diameter: 70 mm × height: 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well in the blending ratios shown in Tables 1 to 3. Next, in Example 4, Example 9 and Example 15, Etacure 300 was introduced into the beaker, and in Example 7, trimethylolpropane was introduced 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 100 ° C. for 30 minutes to cure to obtain a foamed solid lubricant sealed bearing. Using this test piece, the above-mentioned actual machine durability test was performed, and the durability in the actual machine was evaluated. The results are shown in Tables 1 to 3.
Further, the open cell ratio of the foamed solid lubricant was measured based on the above-described method for calculating the open cell ratio. The results are shown in Tables 1 to 3.

Comparative Example 1
After foaming and curing without using a lubricating oil, a test piece of a post-impregnated foamed solid lubricant-enclosed bearing was obtained by the same treatment as in Example 1 except that the lubricating oil was post-impregnated. The actual machine durability test shown below was performed using this test piece, and the durability in the actual machine was evaluated. The results are also shown in Table 3.

  As shown in Tables 1 to 3, the Examples were able to maintain good lubricity even at high temperatures.

  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.

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 plain 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 (9)

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 urethane prepolymer having an isocyanate group in the molecule, a curing agent, and a foaming agent.
The lubricating component is at least one lubricating component selected from lubricating oil and grease;
The urethane prepolymer has an isocyanate group content of 2 wt% or more and less than 6 wt%,
The blowing agent is water;
The foamed solid lubricant-enclosed bearing, wherein the mixture contains 30 to 70% by weight of the lubricating component with respect to the whole mixture, and has an open cell ratio after foaming of 50% or more.   The foamed solid lubricant according to claim 1, 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). The foamed solid lubricant-enclosed bearing according to claim 1 or 2.   The ratio between 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-enclosed bearing according to claim 2 or claim 3.   5. The foamed solid lubricant encapsulated bearing according to claim 1, wherein the curing agent is an aromatic polyamino compound.   6. The foamed solid lubricant encapsulated bearing according to claim 5, wherein the aromatic polyamino compound is an aromatic polyamino compound having a substituent at a position adjacent to an amino group.   The foamed solid lubricant encapsulated bearing according to any one of claims 1 to 6, wherein the mixture is encapsulated at least around a rolling element and then foamed and cured.   The foamed solid lubricant encapsulated bearing according to claim 1, wherein the bearing is a rolling bearing.   The foamed solid lubricant encapsulated bearing according to claim 1, wherein the bearing is a sliding bearing.

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