JP2008275151A - Universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a universal joint meeting demands of a longer life and lower cost for improving the lubricant holding force of foam lubricant which holds lubricating components while keeping the oozing amount of the lubricant with the deformation of the foam lubricant to a required minimum and covering a lubricating function even when the lubricating components from the foam lubricant gets short. <P>SOLUTION: In the universal joint, rotating torque is transmitted with the engagement of track grooves 3, 4 provided in an outward member 2 and an inward member 1 with a torque transmission member 5, the torque transmission member 5 is moved in the axial direction while rolling along the track grooves 3, 4, and auxiliary lubricating grease 10 and the foam lubricant containing the lubricating components in a resin to be foamed, hardened and changed into a porous form coexist inside. The auxiliary lubricating grease satisfies either (1) consistency being less than 285 or (2) the mixing rate of thickener being 10 wt.% or more and less than 40 wt.%. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a universal joint (joint) in which auxiliary lubricating grease and foamed lubricant coexist.

In recent years, higher performance, smaller size, and lighter weight of automobiles have been progressed, and even a constant velocity joint used for drive transmission is required to have a longer life in addition to the above performance. As a result of the reduction in size and weight, a high load is applied to the constant velocity joint, and the conventional grease may not always have a sufficiently long life. As higher performance is required in the future, it is difficult to completely address the above problems simply by optimizing the amount of grease and additives, and research and development of new lubricants and new lubrication mechanisms Is required. In response to such a problem, this foamed lubricant has been reported by foaming a solid component and impregnating it with a lubricating oil (see Patent Document 1).
This follows the boot which is deformed by the bending of the joint and the solid lubricant is compressed. Here, the liquid lubricant that has oozed out of the solid lubricant is supplied to the necessary part, thereby enabling good lubrication.

  The method of containing the lubricant reported here is an impregnated type after impregnating the foamed resin with the lubricating oil. When such a material is used, the lubricating oil is not contained in the solid component. There is a drawback in that the lubricating oil retention force is small, and when used under high-speed conditions, the lubricating oil escapes at once. Such materials can be used for lubrication in a short time or in a closed space, but are difficult to use for a long time or in an open space. Further, since the oil retention is not high, the lubricant constantly flows in the space while repeating the release of the lubricating oil and the absorption into the foam. In such a case, depending on the chemical properties of the lubricant and the additives contained therein, there is a possibility that the boot material may be attacked and deteriorated, and either one of the materials is limited. In addition, it is inevitable that the number of man-hours for the manufacturing process accompanying post-impregnation, the manufacturing time, and the associated cost increase will be increased.

For these reasons, there is a need for a constant velocity joint lubricant that has high lubricant retention and allows large deformation. In particular, it is necessary to include a lubricant in the solid component to increase the lubricant retention.
Compared to grease lubrication that is widely used industrially, such solid lubricants can supply the required amount to the necessary locations, reducing costs by reducing the amount of grease used, and boot materials. This technology has the advantage that it is a technology that makes it possible to reduce the load on the constant velocity, make the constant velocity joint lighter and more compact, and is socially important not only from an economic point of view, but also from multiple viewpoints, including a reduction in environmental load and freedom of design It can be said that this is a high-level technology.

The foamed lubricant-encapsulated constant velocity joint, which has many advantages as described above, may have a small amount of lubricant release due to external force or temperature rise depending on how it is used. In view of durability, it is desirable that the release of the lubricating component from the resin component is the minimum necessary. If the release speed of the lubricating component is small, the speed at which the necessary amount of lubricant reaches the sliding portion becomes slow. For this reason, the lubricant is depleted and wear and lubrication may be caused even in the sliding portion.
Japanese Patent Laid-Open No. 9-42297

  The present invention has been made in order to cope with such problems, and improves the lubricant retention of the foamed lubricant that retains the lubricating component, and the amount of lubricant oozing due to deformation of the foamed lubricant. The purpose of the present invention is to provide a universal joint that can meet the demands of long life and low cost, which can supplement the lubrication function even when the lubricating component from the foamed lubricant is insufficient. To do.

In the universal joint of the present invention, the rotational torque is transmitted by the engagement between the track grooves provided in the outer member and the inner member and the torque transmission member, and the torque transmission member rolls along the track groove. Is a universal joint in which an auxiliary lubricating grease and a foamed lubricant containing a lubricating component in a resin that is foamed and cured to become porous coexist in the interior. The grease must satisfy at least one of (1) a consistency of less than 285, or (2) a blending ratio of a thickener in the grease of 10% by weight or more and less than 40% by weight. It is characterized by.
In addition, the said penetration degree represents the 60 degree of penetration penetration measured based on JISK22205.3.

  The auxiliary lubricating grease is sealed in at least one selected from an outer member bottom portion, a rolling portion, and a sliding portion of the universal joint.

The foamed lubricant is characterized in that the resin that is foamed and cured to become porous has rubber-like elasticity, and the lubricating component contained in the resin has exudation properties due to deformation of the rubber-like elastic body.
Further, the open cell ratio of the resin that is foamed and cured to become porous is 50% or more.
The universal joint is a constant velocity universal joint.

  The foaming lubricant is obtained by foaming and curing a mixture containing a lubricating component, the resin, a curing agent, and a foaming agent, and the lubricating component is at least one selected from a lubricating oil and a grease, The resin is a urethane prepolymer containing 2% by weight or more and less than 6% by weight of isocyanate groups in the molecule, the foaming agent is water, and the mixture contains 30 to 70 lubricant components with respect to the entire mixture. It is characterized by containing wt%.

  The urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.

The ratio of the isocyanate group and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). .
The ratio of the hydroxyl group of water to the functional group of the curing agent is an equivalent ratio (hydroxyl group of water / functional group of the curing agent) = 1 / (0.7 to 2.0).
The curing agent is an aromatic polyamino compound.
Further, the aromatic polyamino compound is an aromatic polyamino compound having a substituent at a position adjacent to the amino group.

The universal joint of the present invention is a universal joint in which an auxiliary lubrication grease and a foaming lubricant containing a lubricating component in a resin that is foamed and cured to become porous coexist, and the auxiliary lubrication Grease is a grease that satisfies at least one of (1) a consistency of less than 285 or (2) a blending ratio of thickener of 10% by weight or more and less than 40% by weight. For this reason, even when centrifugal force is applied, the auxiliary lubricating grease does not easily flow out of the sliding portion, and even when the lubricating component that oozes out from the foamed lubricant is insufficient, the auxiliary lubricating grease can serve a lubricating function. it can.
As a result, the lubrication function can be satisfactorily continued without running out of the lubricant in the sliding portion such as a universal joint in which the foamed lubricant is sealed.

  In this invention, since the lubricating component is retained in the resin, the lubricating component is exuded by deformation due to external force such as compression, expansion, bending, torsion, etc. due to the flexibility of the resin, and is gradually released from between the molecules of the resin. it can. At this time, the amount of the lubricating component 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 component.

  Further, the resin in the foamed lubricant encapsulated in the universal joint of the present invention has a large surface area due to foaming, and the exuded excess lubricating component can be temporarily held in the pores again. The amount of the lubricating component that oozes out is stable, and the amount of lubricant retained is larger than the non-foamed state by retaining the lubricating component in the resin and impregnating the pores.

  In addition, by encapsulating the foamed lubricant, the lubricant can be present near the sliding portion of the universal joint, and the lubricant is more easily supplied to the sliding portion as compared with lubrication of grease or lubricating oil alone. In addition, since there are many porous portions, the weight of the universal joint can be reduced.

  The universal joint of this invention is demonstrated concretely based on drawing. FIG. 1 is a sectional view showing a constant velocity universal joint which is an example of an embodiment of the present invention. As shown in FIG. 1, the constant velocity universal joint includes an inner member 1, an outer member 2, an inner member side track groove 3, an outer member side track groove 4, a steel ball 5, a cage 6, a shaft 7, a boot 8, It is comprised from the foaming lubricant 9, the auxiliary | assistant lubrication grease 10, and other accessory parts. At this time, the auxiliary lubricating grease 10 is disposed in the vicinity of the steel ball 5 in the track portion, and the foamed lubricant 9 is disposed in a space surrounded by the outer member side track groove 4 on which the steel ball 5 slides in the rotation direction. Coexist in.

  FIG. 2 is a sectional view showing a constant velocity universal joint which is another example of the embodiment of the present invention. As shown in FIG. 2, the constant velocity universal joint includes an inner member (not shown), an outer member 2, an inner member side track groove (not shown), an outer member side track groove 4, a steel ball 5, and a plurality of balls. It comprises a cage 6 having a cage window 6a, a shaft 7, a boot 8, a foaming lubricant 9, an auxiliary lubricating grease 10 and other accessory parts. At this time, the auxiliary lubricating grease 10 is accommodated in the vicinity of the steel ball 5 of the cage window 6a, and the foamed lubricant 9 is disposed in a space surrounded by the outer member side track groove 4 in which the steel ball 5 slides in the rotational direction. It coexists in a form.

  FIG. 3 is a sectional view showing a constant velocity universal joint which is another example of the embodiment of the present invention. As shown in FIG. 3, the constant velocity universal joint includes an inner member 1, an outer member 2, an inner member side track groove 3, an outer member side track groove 4, a steel ball 5, a cage 6, a shaft 7, a boot 8, It is comprised from the foaming lubricant 9, the auxiliary | assistant lubrication grease 10, and other accessory parts. At this time, in the constant velocity universal joint, the auxiliary lubricating grease 10 is accommodated in the bottom of the outer member 2, and the foamed lubricant 9 coexists in the form of being disposed in the vicinity of the steel ball 5.

The foamed lubricant 9 contains a lubricating component in a foamed, cured and porous resin, and the centrifugal force generated by the rotation of the constant velocity universal joint and the compression generated when the constant velocity universal joint takes an angle. Lubricating components on the inner member-side track groove 3, outer member-side track groove 4, steel ball 5 surface, cage 6 surface, etc., which are sliding parts from the foamed lubricant due to external stress such as bending and expansion Release slowly.
Further, the auxiliary lubricating grease 10 disposed in the vicinity of the steel ball 5 in the track portion, in the vicinity of the steel ball 5 in the cage window 6a, or in the bottom portion of the outer member 2 is different from the lubricating component in the foamed lubricant, and is contained in the resin. Since it is not contained, it is possible to contribute to the lubrication of the sliding portion and the rolling portion of the constant velocity universal joint even when the lubricating component in the foamed lubricant does not ooze out or when the oozing amount is insufficient.

  The amount of the auxiliary lubricating grease 10 enclosed in the universal joint is preferably 1 to 50% by volume of the space volume inside the universal joint. More preferably, it is 3 to 40% by volume. If the amount is too small, the amount of lubricant used as auxiliary lubrication is insufficient. If the amount is too large, the amount of the foamed lubricant that contributes to lubrication over a long period of time decreases, resulting in a problem in durability.

  The place where the auxiliary lubricating grease 10 is sealed or applied is not particularly limited, but is preferably in the vicinity of the bottom of the outer member, the rolling part, or the sliding part in the universal joint. The specific part of the rolling part is the vicinity of the steel ball of the track part, and the specific part of the sliding part is the cage inner diameter / outer diameter surface, the cage window, the outer member-cage-inner member. A spherical part is mentioned, respectively (refer FIGS. 1-3). It is easy to contribute directly to lubrication by enclosing the auxiliary lubricating grease 10 in the portion. Even when sealed at the bottom of the outer member, it is gradually supplied to the vicinity of the sliding portion or rolling portion in the joint by centrifugal force or bending motion.

  There is no limitation on the method of enclosing the auxiliary lubricating grease 10 in the universal joint. Before filling the universal joint with foamed lubricant, auxiliary lubrication grease may be sealed or applied in the universal joint or its parts, or after filling the universal joint with foamed lubricant, the syringe (or similar) May be injected into the target location.

Examples of using the universal joint of the present invention as a constant velocity universal joint include a ball fixed joint (hereinafter referred to as BJ), an undercut free joint (hereinafter referred to as UJ), and the like. The number of balls of such BJ and UJ may be 6 or 8.
When a foamed lubricant is enclosed in BJ or UJ, the lubricant is filled only in the necessary parts. This contributes to cost reduction and weight reduction, and because the operating angle used is large, compression and It is easy to bend and the lubricant is easily supplied to the rolling part and the sliding part.
Examples of use for sliding constant velocity universal joints include double offset joints, tripod joints, and cross groove joints.
Moreover, a cross joint etc. are mentioned as an inconstant velocity universal joint.

  Foaming lubricants release the lubricating components to the outside due to external stresses such as centrifugal force, compression, bending, and expansion, etc., so that the lubricating components do not ooze out from the foaming lubricant or the lubricating components are depleted. Then, there may be a case where the lubricating component is not sufficiently present in the sliding portion. In the present invention, the shortage of the lubricating component that oozes out from the foamed lubricant can be compensated by using the auxiliary lubricating grease together. In particular, the consistency of the grease for auxiliary lubrication is less than 285 as will be described later, or the blending ratio of the thickener is 10% by weight or more and less than 40% by weight. It is easy to be present in the sliding portion, prevents metal contact at the sliding portion, becomes a cushioning material, and can secure lubricity over a long period of time.

In the present invention, the foamed lubricant can be gradually released from between the molecules of the resin by oozing out the lubricant by deformation due to external force such as compression, expansion, bending, and twisting due to the flexibility of the resin. At this time, the amount of the lubricating component such as 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 lubricant used in the present invention, the resin has a large surface area due to foaming, and the lubricating oil, which is an excess lubricating component that has oozed out, can be temporarily held in the foam bubbles again. The amount of lubricating oil that oozes out is stable, and by retaining the lubricating oil in the resin and impregnating the bubbles in the foam, the amount of the lubricating oil retained is larger than in 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 torque transmission member, it can be easily deformed because the required energy is small at the time of bending and deformation, The problem of increased rotational torque can be prevented. Moreover, since it has many foamed parts, ie, a porous part, it is advantageous also at the point of weight reduction.
In addition, since the foamed lubricant used in the present invention only foams and cures the mixture containing the lubricating component and the resin, no special equipment is required, and it can be filled in any place and molded. is there.
Further, the density of the foamed lubricant can be changed by controlling the blending amount of the blending components of the mixture.

In the present invention, the foaming / curing resin that forms the foamed lubricant is preferably a resin that has a rubber-like elasticity after foaming / curing and has an exudation property of a lubricating component due to deformation.
Foaming / curing may be in a form in which foaming / curing is performed when the resin is produced, or in a form in which a foaming agent is blended with the resin and foaming / curing is performed in molding. Here, curing means a cross-linking reaction and / or a phenomenon in which a liquid is solidified. The rubber-like elasticity means rubber elasticity and means that deformation applied by an external force returns to the original shape by eliminating the external force.

Examples of the resin that becomes porous by foaming and curing include rubber and plastic.
Examples of the rubber include various rubbers such as natural rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, butyl rubber, nitrile rubber, ethylene propylene rubber, silicone rubber, urethane elastomer, fluorine rubber, and chlorosulfone rubber.
Examples of the plastic include general-purpose plastics such as polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyvinyl chloride resin, polyacetal resin, polyamide 4,6 resin, polyamide 6,6 resin, polyamide 6T resin, and polyamide 9T resin. Engineering plastics.
Among the above resins, a polyurethane resin that is easily foamed and cured to be porous is preferable.

  The polyurethane resin that can be used in the present invention is a foamed / cured product obtained by a reaction between an isocyanate and a polyol, and is preferably a foamed / cured product of a urethane prepolymer having an isocyanate group (—NCO) in the molecule. By using a urethane prepolymer, it is excellent in heat resistance and flexibility and can be reduced in cost.

  The urethane prepolymer can be obtained by reacting a compound having an active hydrogen group with a polyisocyanate. The isocyanate group may be a molecular chain terminal or may be contained at a side chain terminal branched from the molecular chain. The urethane prepolymer may have a urethane bond in the molecular chain.

  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. (3- to 8-valent ones) For example, glycerin, trimethylolpropane, hexanetriol, pentaerythritol, sorbitol, shoelace and the like.

  Examples of the polyether polyol include alkylene oxide (alkylene oxide having 2 to 4 carbon atoms, for example, 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 acylated products, 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.

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.
Examples of the polylactone ester polyol include those obtained by ring-opening reaction of caprolactone, and a urethane prepolymer obtained by addition polymerization of this with a polyisocyanate in the presence of a short-chain polyol is preferable.
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.

  If the commercial item of the urethane prepolymer which can be used conveniently for this invention is illustrated, the brand name Plaxel EP by Daicel Chemical Industries may be mentioned. Plaxel EP is a white solid urethane prepolymer having a melting point above room temperature. As an example of polyether polyol, trade name Preminol manufactured by Asahi Glass Co., Ltd. may be mentioned. Preminol is a polyether polyol having a molecular weight of 5000-12000.

  Examples of other commercially available urethane prepolymers that can be used in the present invention include Takenate L-1170 (Mitsui Chemical Polyurethane), L-1158 (Mitsui Chemical Polyurethane), Coronate 4090 (Nippon Polyurethane), Examples include Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.), Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), and Sianaprene 7-QM (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.).

  Moreover, the oligomer and prepolymer compound which modified the terminal group into the isocyanate group can also be used. Examples of such a compound include a terminal isocyanate-modified polyether polyol and an isocyanate-modified product of a hydroxyl group-terminated polybutadiene. Examples of the terminal isocyanate-modified polyether polyol include Coronate 1050 (manufactured by Nippon Polyurethane Co., Ltd.). Moreover, poly-bd MC50 (made by Idemitsu Kosan Co., Ltd.) and poly-bd HTP9 (made by Idemitsu Kosan Co., Ltd.) are mentioned as the isocyanate modified body of hydroxyl-terminated polybutadiene.

  These urethane prepolymers can be used in combination of two or more depending on the desired mechanical properties.

In the present invention, it is preferable to use a urethane prepolymer having an isocyanate group content of 2% by weight or more and less than 6% by weight. If the content of isocyanate group (-NCO) is less than 2% by weight, it becomes difficult to achieve both foamability and elasticity, and if it is more than 6% by weight, the hardness becomes too large and the resilience becomes large and deformation due to external force. 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.

As the curing agent for curing the urethane prepolymer, a compound having active hydrogen is preferable, and examples thereof include a polyamino compound whose functional group is an amino group.
Polyamino compounds include 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter referred to as MOCA), 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dimethoxy- 4,4'-diaminodiphenylmethane, 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-diethyltoluene-2,4-diamine, aroma represented by 3,5-diethyltoluene-2,6-diamine Group polyamino compounds.

  When the urethane prepolymer is cured with a polyamino compound, a foamed 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.

  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.

  Curing agents other than polyamino compounds include the above polyisocyanates, low molecular polyols such as 1,4-butane glycol and trimethylolpropane, polyether polyols, castor oil polyols, polyester polyols, hydroxyl-terminated liquid polybutadienes, hydroxyl-terminated terminals. Examples thereof include liquid polyisoprene, hydroxyl group-terminated polyolefin-based polyols, and liquid rubbers having two or more hydroxyl groups represented by compounds obtained by modifying terminal hydroxyl groups of these compounds with isocyanate groups or epoxy groups.

  The above curing agents can be used alone or in combination.

The ratio of the isocyanate group (—NCO) contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio when the functional group is an amino group or a hydroxyl group (functional group of the curing agent). /NCO)=1/(1.1 to 2.5).
The ratio of the isocyanate group contained in the urethane prepolymer, the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent, and the hydroxyl group of water (—OH) as the blowing agent, and the foaming ratio and flexibility of the foamed lubricant Sex, 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.
When the amount of the curing agent is less than the above range, not only the physical properties such as the strength of the foamed lubricant are remarkably lowered, but also the urethane elastomer may not be cured.

  As a means for foaming the resin in order to obtain a foamed lubricant, a known foaming means may be employed. For example, a chemical foaming method for generating a volatile gas by a chemical reaction, water, acetone, hexane or the like Physical methods for heating and vaporizing organic solvents with low boiling points, mechanical foaming methods for blowing inert gases such as nitrogen and air from the outside, azobisisobutyronitrile (AIBN), azodicarbonamide (ADCA), etc. Examples of such a method include using a decomposable foaming agent that is chemically decomposed by heat treatment or light irradiation to generate nitrogen gas or the like.

  Since the urethane prepolymer used in the present invention has an isocyanate group in the molecule, it is preferable to use a chemical foaming method using carbon dioxide generated by a chemical reaction between the isocyanate group and the water molecule using water as a foaming agent. This method is preferable because open cells are easily generated.

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.

  Without being limited to the above resins, various adhesives such as urethane adhesives, cyanoacrylate adhesives, epoxy adhesives, polyvinyl acetate adhesives, polyimide adhesives, and the like can be used by foaming and curing. .

  In the present invention, various additives may be used as necessary in the resin that is foamed and cured to make it porous. 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 lubricating component that can be impregnated into the resin that is made porous by curing and foaming can be used as long as it does not dissolve the solid component that forms the foam. As the lubricating component, for example, lubricating oil, grease, wax and the like can be used alone or in combination of two or more.
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.
When the foamed and hardened resin and lubricating oil do not dissolve or disperse due to chemical compatibility such as polarity, it is easier to physically mix them by using a lubricating oil with a close viscosity, It becomes possible to prevent segregation of the lubricating 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. Thickeners include, but are not limited to, 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. It is not a thing.

The diurea compound is obtained, for example, by reaction of diisocyanate and monoamine. Examples of the diisocyanate include phenylene diisocyanate, diphenyl diisocyanate, phenyl diisocyanate, diphenylmethane diisocyanate, octadecane diisocyanate, decane diisocyanate, and hexane diisocyanate.
Examples of the monoamine include octylamine, dodecylamine, hexadecylamine, octadecylamine, oleylamine, aniline, p-toluidine, cyclohexylamine and the like.

  The polyurea compound is obtained, for example, by reacting diisocyanate with monoamine and 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 does not solidify even at low temperatures and remains liquid.

  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.

  The lubricating components described above 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 phenols, Antirust agents such as petroleum sulfonate, dinonylnaphthalene sulfonate, sorbitan ester, extreme pressure agents such as sulfur and sulfur-phosphorus compounds, anti-wear agents such as organic zinc and phosphorus compounds, benzotriazole, sodium nitrite, etc. Various additives such as a metal deactivator, a viscosity index improver such as 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, resin, curing agent, and foaming agent.
The blending ratio of the lubricating component is 1 to 90% by weight, preferably 5 to 80% by weight, particularly preferably 30 to 70% by weight, based on the entire mixture. When the lubricating component is less than 1% by weight, the supply amount of the lubricating component is small and the function as a foaming lubricant cannot be exhibited, and when it exceeds 90% by weight, it does not solidify.
The blending ratio of the resin 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 the function as a foaming lubricant cannot be exhibited.

  The blending ratio of the curing agent is determined depending on the blending ratio of the resin and the foaming ratio, and the blending ratio of the foaming agent is determined in relation to the foaming ratio described later.

The method of mixing each component when producing the foamed lubricant is not particularly limited, and for example, mixing using a generally used stirrer such as a Henschel mixer, ribbon mixer, juicer mixer, mixing head, etc. Can do.
The mixture preferably uses a surfactant such as a commercially available silicone foam stabilizer, and each raw material molecule is preferably dispersed uniformly. Further, the surface tension can be controlled by the type of the foam stabilizer, and the type of the generated bubbles can be controlled to open cells or closed cells. Examples of such surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, and fluorine surfactants.

The foaming lubricant used in the present invention comprises a lubricating component in a resin that is foamed and cured to become porous, and the lubricating oil is externally applied by external forces such as compression, bending, centrifugal force, and expansion of bubbles accompanying a temperature rise. It is possible to supply to.
In the present invention, it is desirable that the foaming lubricant adopts a reactive impregnation method in which a foaming reaction and a curing reaction of a resin are simultaneously performed in the presence of a lubricating component. In this way, it is possible to highly fill the inside of the resin with the lubricating component, and thereafter the post-impregnation step of impregnating and replenishing the lubricant can be omitted.
On the other hand, a foam solid body is molded in advance, and only a post-impregnation method in which this is impregnated with a lubricating component does not allow a sufficient amount of liquid lubricating component to penetrate into the resin. However, if the lubricating oil is released in a short time and used for a long time, the lubricating oil may be insufficiently supplied. For this reason, the post-impregnation step is preferably employed as an auxiliary means for the reactive impregnation method.

  It is preferable that the bubbles to be generated when being made porous by foaming at the time of foaming / curing 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 when necessary, a torque transmission member or sliding part May not be sufficiently supplied around.

  In the present invention, the open cell ratio of the foamed lubricant is preferably 50% or more, more preferably 70% or more. When the open cell ratio is less than 50%, the ratio of the lubricating oil in the resin 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) Sample A is washed with Soxhlet for 3 hours (solvent: petroleum benzine). Then leave it in a thermostatic bath at 80 ° C for 2 hours to completely dry the organic solvent and obtain Sample B. The weight of sample B is measured.
(3) The open cell ratio is calculated by the following procedure.
Open cell ratio = (1- (resin weight of sample B−resin weight of sample A) / weight of lubricating component of sample A) × 100
In addition, the resin weight of sample A and B and the lubrication component weight are calculated by multiplying the weight of sample A and B by the preparation ratio of the composition.
Lubricating components taken into discontinuous closed cells are not released to the outside by Soxhlet cleaning for 3 hours, so the weight of sample B is not reduced. The open cell ratio can be calculated as a result of the release of the lubricating component.

  The expansion ratio of the foamed lubricant used in the present invention is preferably 1.1 to 100 times. More preferably, it is 1.1 to 10 times. This is because 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, or the porous solid is too hard to deform following external stress. There is. If it exceeds 100 times, it will be difficult to obtain the strength to withstand external stress, which may lead to breakage or destruction.

The foamed lubricant may be foamed and cured after pouring a mixture containing the lubricating component and resin into the universal joint, and after foaming and curing at normal pressure, it is post-processed to the desired shape by cutting or grinding. It can also be incorporated into a universal joint.
In the present invention, it is possible to easily fill any part in a universal joint having a complicated shape, and there is no need for a molding die or a grinding process for obtaining a foamed molded article. It is preferable to employ a method of pouring into a universal joint before foaming / curing and foaming / curing in the joint. By adopting this method, the manufacturing process is simplified and the cost can be reduced.

As the auxiliary lubricating grease used in the present invention, (1) the 60-time mixing penetration measured in accordance with JIS K 2220 5.3 is less than 285, or (2) the blending ratio of the thickener is 10% by weight or more. Any grease that satisfies any of the following requirements can be used. It should be noted that at least one of the above conditions of consistency or thickener blending ratio may be satisfied, and both may be satisfied.
When the consistency is 285 or more, the grease easily moves due to the flow caused by centrifugal force or bending motion, so the grease easily flows out of the joint (boot side), and long-term lubricity may not be ensured. . If the blending ratio of the thickener is less than 10% by weight, the grease tends to flow out of the sliding part, and it is difficult to obtain the effect of intervening on the sliding surface to prevent metal contact and become a cushioning material. If it is 40% by weight or more, it becomes too hard and the workability deteriorates.
As the thickener and base oil of the auxiliary lubricating grease, those exemplified as an example of the lubricating component in the foamed lubricant can be used. Similarly, various additives can be included.

<Preparation of auxiliary lubricating grease>
Auxiliary lubricating grease A to auxiliary lubricating grease D used in Examples 1 to 10, Comparative Example 3 and Comparative Example 4 were prepared by the following method. Consistency represents the 60-times penetration consistency measured according to JIS K 2220 5.3.
Auxiliary lubrication grease A
In 77 g of mineral oil (turbine 100: manufactured by Nippon Oil Corporation), 12.39 g of diphenylmethane-4,4-diisocyanate and 10.61 g of p-toluidine are reacted, and the resulting diurea compound is uniformly dispersed to provide a grease for auxiliary lubrication. A was obtained. The amount of thickener in the grease was 23% by weight, and the consistency was measured to be 270.
Auxiliary lubrication grease B
In 91 g of mineral oil (turbine 100: manufactured by Nippon Oil Corporation), 3.64 g of diphenylmethane-4,4-diisocyanate, 3.92 g of stearylamine, and 1.44 g of cyclohexylamine were reacted, and the resulting diurea compound was uniformly dispersed. An auxiliary lubricating grease B was obtained. The amount of thickener in the grease was 9% by weight, and the consistency was measured and found to be 280.
Auxiliary lubrication grease C
In 83 g of mineral oil (turbine 100: manufactured by Nippon Oil Corporation), 9.16 g of diphenylmethane-4,4-diisocyanate and 7.84 g of p-toluidine are reacted, and the resulting diurea compound is uniformly dispersed to obtain grease C. It was. The amount of thickener in the grease was 17% by weight, and the consistency was measured to be 335.
Auxiliary lubrication grease D
Grease D for auxiliary lubrication by reacting 3.94 g of diphenylmethane-4,4-diisocyanate and 4.07 g of octylamine in 92 g of mineral oil (turbine 100: manufactured by Nippon Oil Co., Ltd.) and uniformly dispersing the resulting diurea compound Got. The amount of thickener in the grease was 8% by weight, and the consistency was measured to be 320.

Examples 1 to 8
First, as shown in FIG. 3, the outer side of the outer member 2, the inner member 1, the cage 6 and the steel ball 5 is fixed to the fixed eight ball joint sub-assy (EBJ82 outer diameter size 72.6 mm manufactured by NTN Corporation). The auxiliary lubricating grease shown in Table 1 was sealed at the bottom of the member. Next, (a), (d), (e) and (i) of the composition shown in Table 1 are mixed well at 80 ° C, and then quickly mixed by adding (b) dissolved at 120 ° C or 130 ° C. did. Finally, (c) and (h) were added and stirred, and then 18.0 g was sealed in the joint subassembly with the auxiliary lubricating grease sealed therein. After a few seconds, the foaming reaction started, and it was allowed to stand for 30 minutes in a thermostat set at 100 ° C. to cure, and other sections such as boots and shafts were assembled to obtain a test piece of a constant velocity universal joint. The obtained test piece was subjected to the durability test shown below, and the lifetime was measured. 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.

<Durability test using constant velocity universal joint>
In order to evaluate whether or not the target durability has been improved, the constant velocity universal joint test piece was evaluated under the following conditions. If the outer member surface temperature exceeded 100 ° C during the test, the test was terminated due to an abnormal temperature rise. In addition, after the test, the inside of the test piece is inspected, and if there is no internal damage such as wear or peeling, it is judged as acceptable, “○” is judged, and if the damage is confirmed, judged as impossible, “×”. Record.
・ Torque 451 N ・ m
・ Angle 6 deg
・ Rotation speed 580 rpm
・ Test time 300 hours

Example 9 and Example 10
First, as shown in FIG. 3, the outer side of the outer member 2, the inner member 1, the cage 6 and the steel ball 5 is fixed to the fixed eight ball joint sub-assy (EBJ82 outer diameter size 72.6 mm manufactured by NTN Corporation). 3 g of auxiliary lubricating grease shown in Table 1 was sealed at the bottom of the member. In the component amounts (composition) shown in Table 1, silicone-based foam stabilizer, mineral oil, amine-based catalyst, and water as a blowing agent were added to the polyether polyol, and the mixture was heated at 90 ° C. and stirred well. After adding isocyanate to this and stirring well, 16.0 g was sealed in the joint sub-assembly in which the auxiliary lubricating grease A was sealed. After a few seconds, the foaming reaction started, and it was allowed to stand for 15 minutes in a thermostat set at 90 ° C. to cure, and other sections such as boots and shafts were assembled to obtain a specimen of a constant velocity universal joint. Items similar to those in Example 1 were measured. The results are also shown in Table 1.

Comparative Example 1
Test specimens of constant velocity universal joints having the composition shown in Table 1 were prepared in the same procedure as in Example 2, but no auxiliary lubricating grease was enclosed. Items similar to those in Example 1 were measured. The results are also shown in Table 1.

Comparative Example 2
A constant velocity universal joint specimen with the composition shown in Table 1 was prepared in the same procedure as in Example 9, but no grease for auxiliary lubrication was enclosed. Items similar to those in Example 1 were measured. The results are also shown in Table 1.

Comparative Example 3
A constant velocity universal joint specimen was obtained with the composition shown in Table 1 in the same procedure as in Example 2. As the auxiliary lubricating grease, auxiliary lubricating grease D having a thickener amount of 8% by weight was used. Items similar to those in Example 1 were measured. The results are also shown in Table 1.

Comparative Example 4
A test joint was obtained in the same procedure as in Example 9 with the composition shown in Table 1 (no silicone foam stabilizer). As the auxiliary lubricating grease, the auxiliary lubricating grease C having a thickener amount of 17% by weight was used, but the open cell ratio of the foamed lubricant was 40%. Items similar to those in Example 1 were measured. The results are also shown in Table 1.

  As can be seen from the results shown in Table 1, Examples 1 to 10 did not show wear due to lack of lubricant using actual joints, and showed good results.

  The universal joint of the present invention has an excellent lubricant holding force, suppresses the amount of lubricant oozing out even if it is deformed by an external force, and lubricates even when the lubricating component from the foamed lubricant is insufficient. As a universal joint for various industrial machines such as stranded wire machines, electric equipment, printing machines, automobile parts, electrical accessories, construction machines, etc., especially for automobiles, etc. It can be suitably used as a quick universal joint.

It is sectional drawing which shows the constant velocity universal joint which is an example of embodiment of this invention. It is sectional drawing which shows the constant velocity universal joint which is the other example of embodiment of this invention. It is sectional drawing which shows the constant velocity universal joint which is the other example of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 3 Inner member side track groove 4 Outer member side track groove 5 Steel ball (torque transmission member)
6 Cage 7 Shaft 8 Boot 9 Foam lubricant 10 Auxiliary lubrication grease

Claims (11)

Rotational torque is transmitted by the engagement between the track groove and the torque transmission member provided in the outer member and the inner member, and the torque transmission member rolls along the track groove to perform axial movement. A universal joint in which an auxiliary lubricating grease and a foamed lubricant containing a lubricating component in a resin that is foamed and cured to become porous coexist,
The auxiliary lubricating grease satisfies at least one of (1) a consistency of less than 285, or (2) a blending ratio of the thickener in the grease of 10% by weight or more and less than 40% by weight. Universal joint characterized by being grease.   The universal joint according to claim 1, wherein the auxiliary lubricating grease is sealed in at least one selected from an outer member bottom portion, a rolling portion, and a sliding portion of the universal joint.   The foamed lubricant is characterized in that a resin that foams and hardens to become porous has rubber-like elasticity, and a lubricating component contained in the resin has exudation properties due to deformation of the rubber-like elastic body. The universal joint according to claim 1 or claim 2.   4. The universal joint according to claim 1, wherein the open cell ratio of the resin that is foamed and cured to be porous is 50% or more. The foaming lubricant is obtained by foaming and curing a mixture containing a lubricating component, the resin, a curing agent, and a foaming agent,
The lubricating component is at least one selected from lubricating oil and grease;
The resin is a urethane prepolymer containing 2 wt% or more and less than 6 wt% of isocyanate groups in the molecule,
The blowing agent is water;
The universal joint according to any one of claims 1 to 4, wherein the mixture contains 30 to 70% by weight of the lubricating component with respect to the whole mixture.   6. The universal joint according to claim 5, wherein the urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.   The ratio of the isocyanate group and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). The universal joint according to claim 5 or 6.   The ratio of the hydroxyl group of the 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). The universal joint according to claim 6 or 7.   The universal joint according to any one of claims 5 to 8, wherein the curing agent is an aromatic polyamino compound.   The universal joint according to claim 9, wherein the aromatic polyamino compound is an aromatic polyamino compound having a substituent adjacent to the amino group.   The universal joint according to any one of claims 1 to 10, wherein the universal joint is a constant velocity universal joint.

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