JP2008138708A - One-way clutch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch in which lubricant is not dispersed by centrifugal force at the time of one-way clutch racing, but exists at the time of engagement. <P>SOLUTION: The one-way clutch comprises: an outer ring 11; an inner ring 12 rotatable relatively to the outer ring 11; a plurality of engaging elements 13 which are arranged circumferentially with spaces between the outer ring and inner ring, and engages both rings by engaging with outer ring inner peripheral surface and inner ring outer periphery when the outer ring and the inner ring rotate relatively; a retainer 14 holding each engaging element 13; and an elastic member which biases the each engaging element 13 in an engagement direction to the inner peripheral surface and the inner periphery, and the one-way clutch is formed by enclosing porous solid lubricant 2 between the outer ring and inner ring. The porous solid lubricant indispensably consists of lubricant component and resin component, and is solid mass porously formed by processing the resin component in foaming and curing. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a one-way clutch that transmits and shuts off rotational torque, and more particularly to a one-way clutch that lubricates a friction engagement surface of an engagement element with a porous solid lubricant.

One-way clutches that use wedge effects such as sprags and rollers require (1) high μ characteristics on the contact surface when engaged, while (2) wear resistance on the contact surface during idle rotation. Needed. These requirements are influenced by the clutch operating temperature, and (1) is disadvantageous at low temperatures, and (2) is disadvantageous at high temperatures. In particular, the former is an important factor that affects the merchantability, and improvement has been desired.
In general, a mechanical one-way clutch using an engagement element is an engagement element such as a sprag or a roller that engages the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to couple the two wheels when the outer ring and the inner ring rotate relative to each other in one direction. The engaging element is urged by an elastic member in a direction to engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. Lubricating grease is filled between the outer ring and the inner ring, thereby lubricating the contact portion between the engagement element and the outer ring and the inner ring at the time of idling.

  Such a one-way clutch is incorporated in a rotor of an auxiliary machine such as an air conditioner, an alternator, a water pump, and a cooling fan that is built in a pulley unit and driven via a belt from a crankshaft of an automobile engine, for example. ing.

  When transmitting the main power from the engine etc. to the driven power shaft of the driven auxiliary machine with the equipped one-way clutch, in order to maintain the power shaft on the auxiliary machine side with inertia force as much as possible and increase the power transmission efficiency, For example, according to the rotation difference between the pulley and the rotor, the power transmission state and the cutoff state are switched by a one-way clutch so that the rotor of the auxiliary machine is continuously rotated with as little power as possible. At the time of power transmission, it is necessary to apply high pressure to the friction contact surface by utilizing the wedge effect and engage with a high frictional force. At the time of power interruption, the sliding contact surface at the important point where the wheel rotates is required to have wear resistance.

  By the way, the wear resistance characteristics of the sliding contact surface of the one-way clutch are greatly affected by the lubricating grease that is enclosed, and an ether base oil such as alkyldiphenyl ether is used to prevent the oil film from running out of the pulley unit equipped with the one-way clutch. It is known to use an adopted ether grease (see Patent Document 1).

And in order to prevent oil film breakage at the part where the metal contacts at high surface pressure, so-called extreme pressure additive is added to the lubricating grease, but the extreme pressure additive dithiophosphate molybdenum compound or dithiocarbamate molybdenum compound Is used under the condition that the friction coefficient is reduced as much as possible even in the extreme pressure state (see Patent Document 2).
However, in the one-way clutch in the pulley unit filled with grease as described above, the grease moves to the outer ring side due to centrifugal force when idling, and when the clutch is engaged, that is, the friction contact surface is When the pressure is increased, there is a problem that the lubricant is not present and wear is promoted to cause a malfunction.
In particular, it has not been easy to apply a lubricant that does not move due to centrifugal force during idling at high speed to a one-way clutch.
JP 11-82688 A JP 2004-256665 A

  The present invention has been made in order to cope with such problems, and the lubricant is not scattered by the centrifugal force when the one-way clutch is idling, and the lubricant is also applied when the clutch is engaged. An object is to provide an existing one-way clutch.

The one-way clutch of the present invention is a one-way clutch that lubricates a friction engagement surface of an engagement member of a mechanical one-way clutch with a porous solid lubricant, and the porous solid lubricant includes a lubricating component and a resin component. Is an essential component, and the resin component is a solid material which is made porous by curing and foaming.
The mechanical one-way clutch is arranged with an outer ring, an inner ring rotatable relative to the outer ring, and a circumferential interval between the outer ring and the inner ring, and the outer ring and the inner ring are arranged in one direction. When relatively rotated, a plurality of engaging members that engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to couple the two wheels, a cage that holds the engaging members, and the engaging members that are connected to the inner peripheral surface of the outer ring and the inner ring And an elastic member biased in a direction to engage with the outer peripheral surface, wherein the porous solid lubricant is sealed between the outer ring and the inner ring.

The porous solid lubricant is characterized by comprising a resin component made of a resin having rubber elasticity or rubber and having a leaching property of the lubricant component due to deformation by an external force.
The resin component is a polyurethane resin.
Moreover, the open cell ratio of the solid is 50% or more.

  In the one-way clutch of the present invention, by using a porous solid lubricant as a lubricant, the movement of the lubricant can be minimized even if a centrifugal force is generated when the one-way clutch rotates idly. For this reason, the lubricant is not scattered, the lubricant can be sufficiently supplied between the inner ring and the engagement element, and wear can be suppressed even if the number of times the clutch is used increases.

In the one-way clutch of the present invention, by using a porous solid lubricant as a lubricant, the movement of the lubricant can be minimized even when the one-way clutch is idling, and the gap between the inner ring and the engagement element is sufficient. There is an advantage that a lubricant can be supplied.
This porous solid lubricant is a solid material in which a lubricating component and a resin component are essential components, and the resin component is made porous by foaming and curing, and the lubricating component is occluded inside the resin. Unlike a grease, it is a foam having a resin component, so that the solid lubricant itself does not move due to centrifugal force, and there is no lubrication failure between the inner ring and the engagement member due to insufficient lubricant. In addition, the lubricating component occluded in the resin component or in the pores is easily supplied to the lubricating surface of the engaging element due to deformation due to movement of the engaging element, heat generation, capillary action, etc., and the lubricating component is released gradually. Is reliably supplied over a long period of time. Moreover, since it is a foam and can take a large amount of deformation, a reliable sealing property is ensured by elasticity, but since the foam has a high elastic modulus, it does not lead to an increase in torque due to high contact.
In the present invention, “occlusion” means that a liquid / semi-solid lubricating component does not react with other compounding components and is contained in a solid resin without becoming a compound.

  As one form of the one-way clutch of the present invention, an outer ring, an inner ring rotatable relative to the outer ring, and a circumferential interval between the outer ring and the inner ring are arranged, and the outer ring and the inner ring are arranged. When relatively rotating in one direction, a plurality of engagement elements that engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to couple the two wheels, a cage that holds the engagement elements, and the engagement elements that are connected to the inner periphery of the outer ring. And an elastic member that urges in a direction to engage the outer peripheral surface of the surface and the inner ring. The porous solid lubricant filled between the outer ring and the inner ring lubricates the contact portion of the engagement element with the outer ring and the inner ring. A one-way clutch can be employed.

In addition, the one-way clutch having a plurality of engagement elements that engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to couple the two wheels stably and reliably exerts the friction engagement force between the engagement element and each cylindrical surface. In addition, there is an advantage that abnormal wear due to frictional contact between the engagement element and the cylindrical surface of the outer ring and the engagement element and the cylindrical surface of the inner ring can be prevented during idling.
When the outer ring rotates relative to the inner ring, the engaging element in the above structure engages with each cylindrical surface and transmits the rotational torque of the outer ring to the inner ring. At this time, the porous solid lubricant exhibits a predetermined friction coefficient, and stably exhibits the frictional engagement force between the engagement element and each cylindrical surface.

In addition, the engagement element is formed in a cylindrical surface when the outer ring rotates relative to the inner ring in the opposite direction to the above transmission or when the rotation speed of the inner ring rotating in the same direction with respect to the outer ring exceeds the rotation speed of the outer ring. Is disengaged and the rotation transmission from the outer ring to the inner ring is cut off.
In this way, when the one-way clutch rotates idly, the double-row engagement elements rotate relative to the outer ring and the inner ring. Since the engaging element revolves together with the cage while sliding on the cylindrical surface of the outer ring and the cylindrical surface of the inner ring, the porous solid lubricant exhibits predetermined wear resistance, and the engaging element and the cylindrical surface of the outer ring, the engaging element and the inner ring Abnormal wear due to frictional contact with the cylindrical surface is prevented.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, a one-way clutch 10 according to the present invention is incorporated into a pulley 1 to form a pulley with a built-in clutch.
The one-way clutch 10 includes an outer ring 11 press-fitted into the inner diameter surface of the pulley 1, an inner ring 12 incorporated inside the outer ring 11, an engagement element 13 incorporated between the two rings 11, 12, and the engagement element 13 and a resilient member 15 that urges the engaging element 13 in the engaging direction. The lubricating component and the resin component are essential components between the outer ring 11 and the inner ring 12, and the resin component is foamed. A porous solid lubricant 2 that is a solid material that has been cured to be porous is encapsulated.
The outer ring 11 has a shorter axial length than the inner ring 12, and a cylindrical surface 16 is formed on the inner periphery of the outer ring 11. A cylindrical surface 17 is formed on the outer periphery of the inner ring 12 so as to face the cylindrical surface 16 of the outer ring 11 in the radial direction. Further, on the outer periphery of the inner ring 12, bearing fitting surfaces 18 are formed on both sides of the cylindrical surface 17, and a bearing 19 is supported on each bearing fitting surface 18.

The bearing 19 is a ball bearing with a single seal. The bearing 19 is assembled so that the seal 20 is located on the outer side, and the pulley 1 and the inner ring 12 are relatively rotatable by the bearing 19. Grease is sealed between the outer ring 11 and the inner ring 12 between the pair of bearings 19.
The engagement element 13 is made of a sprag. The engagement element 13 is disposed between the cylindrical surface 16 of the outer ring 11 and the cylindrical surface 17 of the inner ring 12 with a gap in the circumferential direction.
The cage 14 is made of a synthetic resin molded product. As shown in FIG. 2, the retainer 14 is formed with a plurality of pockets 21 for individually accommodating the engaging elements 13 and spring accommodating recesses 22 communicating with the pockets 21. An elastic member 15 made of a spring is incorporated in the frame. The elastic member 15 biases the engaging element 13 in a direction in which the engaging element 13 engages with the cylindrical surface 16 of the outer ring 11 and the cylindrical surface 17 of the inner ring 12.

  Here, the engaging element 13 engages with the cylindrical surfaces 16 and 17 when the outer ring 11 together with the pulley 1 rotates relative to the inner ring 12 in the direction of the arrow in FIG. To communicate. Further, in the engaging element 13, the outer ring 11 rotates relative to the inner ring 12 in the opposite direction indicated by the arrow, or the rotation speed of the inner ring 12 rotating in the same direction with respect to the outer ring 11 rotating in the arrow direction is the outer ring. When the rotation speed exceeds 11, the engagement with the cylindrical surfaces 16 and 17 is released, and the rotation transmission from the outer ring 11 to the inner ring 12 is cut off. Flange 23 is provided on both sides in the axial direction on the outer peripheral surface of cage 14.

  As shown in FIG. 1, one end of the cage 14 is located in one bearing 19 and holds the ball 19 a of the bearing 19. As described above, the retainer 14 of the one-way clutch 10 is held by the retainer 14 of the one-way clutch 10, so that the retainer 14 is rotated during the idling of the one-way clutch 10 in which the outer ring 11 rotates relative to the inner ring 12. Thus, the engaging member 13 that rotates together with the retainer 14 can be slid relative to the cylindrical surface 16 of the outer ring 11 and the cylindrical surface 17 of the inner ring 12.

The pulley with a built-in clutch shown in the embodiment has the above-described structure. In this pulley with a built-in clutch, when the pulley 1 rotates in the direction of the arrow in FIG. 2, the engagement element 13 becomes the cylindrical surface 16 of the outer ring 11 and the cylindrical surface of the inner ring 12. 17, and the rotation of the pulley 1 is transmitted to the inner ring 12. When the rotation speed of the inner ring 12 exceeds the rotation speed of the outer ring 11, the engagement of the engaging elements 13 with respect to the cylindrical surfaces 16 and 17 is released, and the rotation transmission from the outer ring 11 to the inner ring 12 is interrupted.
For this reason, when the pulley with a clutch as described above is attached to the rotating shaft of the alternator, for example, and the belt is passed between the pulley attached to the crankshaft and the pulley on the rotating shaft, the alternator is driven. At the time of increase, the one-way clutch 10 is engaged, and the rotation of the crankshaft is transmitted to the rotating shaft of the alternator.

Further, when the angular velocity of the crankshaft is reduced, the one-way clutch 10 is in an idling state, and the rotation transmission from the crankshaft to the rotating shaft of the alternator is interrupted.
For this reason, it is possible to prevent slippage between the pulley 1 and the belt applied thereto, and to suppress wear of the belt.
Here, when the one-way clutch 10 idles, the engaging element 13 rotates relative to the outer ring 11 and the inner ring 12. At this time, the engaging element 13 revolves together with the cage 14 while sliding on the cylindrical surface 16 of the outer ring 11 and the cylindrical surface 17 of the inner ring 12.

In the present invention, the resin component constituting the porous solid lubricant is preferably a resin component having rubber-like elasticity after foaming and curing, and having a leaching property of the lubricant component due to deformation.
Foaming / curing may be in a form in which foaming / curing is performed at the time of resin production, or in a form in which a foaming agent is added to the resin component and foaming / curing is performed in molding. Here, curing means a cross-linking reaction and / or a phenomenon in which a liquid is solidified. The rubber-like elasticity means rubber elasticity and means that deformation applied by an external force returns to the original shape by eliminating the external force.

In the present invention, examples of the resin component include rubber and resin.
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 resin 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. This isocyanate group may be blocked by other substituents. The isocyanate group contained in the molecule may be at the end of the molecular chain or may be contained at the end of the side chain branched from the molecular chain. The urethane prepolymer may have a urethane bond in the molecular chain.

The urethane prepolymer can be obtained by reacting a compound having an active hydrogen group with a polyisocyanate.
Examples of the compound having an active hydrogen group include low molecular polyols, polyether polyols, polyester polyols, and castor oil polyols. These can be used alone or as a mixture of two or more. Examples of the low molecular polyol include divalent ones such as ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A, etc. (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 acylates, etc. Obtained by addition polymerization in the presence of a catalyst. The polyether ester polyol can be obtained by addition reaction of a polyester having a carboxyl group and / or a hydroxyl group at the terminal with 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.
The polylactone ester polyol is preferably a urethane prepolymer obtained by addition polymerization of a polyisocyanate in the presence of a short-chain polyol to a polylactone ester polyol obtained by ring-opening reaction of caprolactone.
Examples of the polyether polyol include alkylene oxide addition products or ring-opening polymerization products, and urethane prepolymers obtained by addition polymerization of these with polyisocyanates are preferable.

  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.

  Curing agents for curing the urethane prepolymer include 3,3′-dichloro-4,4′-diaminodiphenylmethane (hereinafter referred to as MOCA) and 4,4′-diamino-3,3′-diethyl-5. Aromatic polyamines typified by 5'-dimethyldiphenylmethane, the above polyisocyanates, low molecular polyols typified by 1,4-butane glycol and trimethylolpropane, polyether polyols, castor oil polyols, polyester polyols, etc. Or it can use together. Among these, an aromatic polyamine which can achieve both foamability and rubber-like elasticity and can be easily obtained industrially, particularly MOCA is preferable for curing a urethane prepolymer obtained by addition polymerization of polylactone ester polyol and polyisocyanate.

  As a means for foaming the resin component, a well-known foaming means may be employed. For example, a chemical foaming method that generates a volatile gas by a chemical reaction, an organic solvent having a relatively low boiling point such as water, acetone, hexane, or the like. Heat treatment such as physical methods for heating and vaporization, mechanical foaming method in which an inert gas such as nitrogen or air is blown from the outside, azobisisobutyronitrile (AIBN), azodicarbonamide (ADCA), etc. Examples include a method of using a decomposable foaming agent that is chemically decomposed by 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 resin components, various adhesives such as urethane adhesives, cyanoacrylate adhesives, epoxy adhesives, polyvinyl acetate adhesives, polyimide adhesives can be used by foaming and curing. .

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

The lubricating component that can be used in the present invention can be used without any choice as long as it does not dissolve the resin 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.
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.
If the resin material and the lubricating oil do not dissolve or disperse due to chemical compatibility such as polarity, it is easier to physically mix and prevent segregation of the lubricant by using a lubricating oil with close viscosity. It becomes.

  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 95% by weight, preferably 5 to 80% 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 the amount is more than 95% by weight, it remains liquid without being hardened with grease even at low temperatures.

  Examples of waxes used in the present invention include hydrocarbon synthetic waxes, polyethylene waxes, fatty acid ester waxes, fatty acid amide waxes, ketones / amines, hydrogenated oils, and the like. As oil components that may be used by mixing oil with these waxes, the same oil components as those described above can be used.

  The 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, Rust inhibitors such as petroleum sulfonate, dinonylnaphthalene sulfonate, sorbitan ester, extreme pressure agents such as sulfur and sulfur-phosphorus, organic zinc, phosphorus and other antiwear agents, metals such as benzotriazole and sodium nitrite Various additives such as viscosity index improvers such as an inert agent, polymethacrylate, and polystyrene may be included.

The porous solid lubricant of the present invention is obtained as a solid material which is made porous by foaming and curing a mixture in which a lubricating component and a resin component are essential components and a curing agent and a foaming agent are blended therein.
The blending ratio of the lubricating component is 1 to 90% by weight, preferably 5 to 80% by weight, based on the entire mixture. When the lubricating component is less than 1% by weight, the supply amount of the lubricating component such as lubricating oil is so small that it cannot function as a solid lubricant, 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 so small that it cannot function as a solid lubricant.

  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 the mixture containing the lubricating component and the resin component as essential components is not particularly limited. For example, mixing is performed using a commonly used stirrer such as a Henschel mixer, a ribbon mixer, a juicer mixer, a mixing head, or the like. 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 porous solid lubricant used in the one-way clutch of the present invention has a lubricating component and a resin component as essential components, and supplies lubricating oil to the outside by external forces such as compression, bending, centrifugal force, and expansion of bubbles accompanying a temperature rise. Is possible.
In order to occlude the lubricating component inside the resin, it is desirable to employ a reactive impregnation method in which a foaming reaction and a curing reaction are simultaneously performed in the presence of the lubricating component. In this way, it is possible to highly fill the inside of the resin with the lubricant, 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 the solid is impregnated with a lubricant does not allow a sufficient amount of liquid lubricant to penetrate into the resin. 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 foamed by foaming at the time of foaming / curing are open cells that communicate with each other, and the lubricating component can be directly removed from the surface of the resin via the open cells by external stress. This is to supply. 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. May not be.

  The open cell ratio of the porous solid lubricant used in the present invention is preferably 50% or more, more preferably 70% or more. When the open cell ratio is less than 50%, the ratio of the lubricating oil in the resin component temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary.

The open cell ratio of the porous solid lubricant used in the present invention can be calculated by the following procedure.
(1) The foam solidified porous solid lubricant is cut into an appropriate size to obtain sample A. The weight of sample A is measured.
(2) Soxhlet A is washed for 3 hours (solvent: petroleum benzine). 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− (weight of resin component of sample B−weight of resin component of sample A) / weight of lubricating component of sample A) × 100
The resin component weight and the lubrication component weight of Samples A and B are calculated by multiplying the weights of Samples A and B by the composition charge ratio.
Lubricating components taken into discontinuous closed cells are not released to the outside by Soxhlet cleaning for 3 hours, so the weight of sample B is not reduced. The open cell ratio can be calculated as the release of the lubricating component.

  The expansion ratio of the porous solid 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 foaming ratio is less than 1.1 times, the bubble volume is small, and deformation is not allowed when external stress is applied, or the solid matter is too hard and cannot be deformed following external stress. If it exceeds 100 times, it will be difficult to obtain the strength to withstand external stress, which may lead to damage or destruction.

  As a method of incorporating the porous solid lubricant into the one-way clutch, for example, a predetermined space of the sub-assembly assembled only around the one-way clutch engaging member is filled with a mixture containing a lubricating component and a resin component as essential components, and foamed. -After curing, a method of assembling a member such as a pulley can be adopted. In this case, since the mixture before foaming / curing is fluid, it is possible to easily fill any part of the one-way clutch having a complicated shape. In addition, when filling the mixture, it can be molded into a predetermined shape by covering the side surface of the predetermined space in the sub-assembly of the one-way clutch with a jig as necessary.

As an incorporation method other than filling the mixture into the sub-assembly of the one-way clutch, there is a method of incorporating a porous solid lubricant formed by foaming and curing after filling into a molding die into the one-way clutch.
There is also a method of foaming and curing the mixture at normal pressure without using a molding die, but in this case, the foamed and cured product is post-processed into the desired shape by cutting or grinding to form a one-way clutch. Must be included. Note that the foamed / cured product obtained at normal pressure may be insufficient in the lubricant content, so it is necessary to ensure a predetermined amount of lubricant by post-impregnation.
These methods require a molding die, and require post-processing such as grinding, post-impregnation, and incorporation. In addition, even if the hardened foam is post-impregnated with a lubricant and added, problems such as poor lubricant retention and easy leakage of the lubricant from the foam during handling for incorporation into a one-way clutch. Prone to occur.
From the above, in the present invention, it is preferable to adopt a method in which the mixture is filled into a sub-assembly of a one-way clutch and foamed and cured in terms of quality, work, and cost.

  In the one-way clutch of the present invention, the lubricating component contained in the impregnated state in the porous solid lubrication does not ooze out suddenly even when the foam is deformed by an external force, and the lubricating component is efficiently made into the sliding surface. It can be used by oozing out. As a result, the amount of the lubricating component may be minimized and a long-life one-way clutch can be obtained. For this reason, it can be used for a one-way clutch, preferably an automobile one-way clutch.

Example 1
Silicone foam stabilizers and urea grease were added to the urethane prepolymer at the blending ratio shown in Table 1, and the mixture was well stirred at 120 ° C. An amine-based curing agent was added and stirred, and water as a foaming agent was added. The liquid material before curing / foaming was poured into the internal space of the one-way clutch, and left in a thermostatic bath set at 120 ° C. for 1 hour to foam / cure to obtain a one-way clutch filled with a porous solid lubricant. . Using the obtained one-way clutch, the following clutch durability test was conducted to evaluate the durability of the clutch function. Further, the open cell ratio of the porous solid lubricant was measured based on the above-described method for calculating the open cell ratio. These results are also shown in Table 1.

<Clutch durability test>
Using a rapid acceleration / deceleration tester, a clutch durability test was performed under the following conditions.
・ Test clutch: NTN one-way clutch built-in pulley (see Fig. 1 and Fig. 2)
-Rapid acceleration / deceleration cycle: Acceleration time 1.2 seconds-Restraint time 8.8 seconds-Deceleration time 1.0 seconds-Stop time 9.0 seconds-Number of rotations: 0 to 20000 rpm
・ Radial load: 1400 N
・ Ambient temperature: 110 ℃
・ Test time: 500 hours ・ Evaluation: After 500 hours, OK if the clutch function is normal, NG if the clutch function is abnormal before 500 hours, and record the failure mode.

Example 2
In the blending ratio shown in Table 1, silicone-based foam stabilizer, mineral oil, amine-based catalyst, and water as a blowing agent were added to polyether polyol, and the mixture was heated at 90 ° C. and stirred well. The isocyanate was added to this and stirred well. The liquid material before curing / foaming was poured into the internal space of the one-way clutch and left in a thermostatic bath set at 90 ° C. for 15 minutes to obtain a one-way clutch enclosing foaming / curing / porous solid lubricant. The same items as in Example 1 were evaluated using the obtained one-way clutch. The results are also shown in Table 1.

Comparative Example 1
The components shown in Table 1 were enclosed in 2.5 g (about 70% of the space volume) to obtain a one-way clutch. The same items as in Example 1 were evaluated using the obtained one-way clutch. The results are also shown in Table 1.

Comparative Example 2
Among the components shown in Table 1, a porous solid lubricant was sealed in the internal space of the clutch by the same method as in Example 1 except for the composition of the lubricating oil. Lubricating oil was impregnated later, and a one-way clutch in which a post-impregnated porous solid lubricant was enclosed was formed. The same items as in Example 1 were evaluated using the obtained one-way clutch. The results are also shown in Table 1.

  As shown in Table 1, in each example, the soundness of the clutch function (locking and idling) was ensured after the required time of 500 hours. In each comparative example, the rotation stopped before reaching 500 hours, and as a result of decomposition, the occurrence of abnormal wear was observed.

  The one-way clutch of the present invention can minimize the movement of the lubricant even if a centrifugal force is generated when the one-way clutch idles. For this reason, the lubricant is not scattered, the lubricant can be sufficiently supplied between the inner ring and the engagement element, and wear can be suppressed even if the number of times the clutch is used increases. As a result, it can be suitably used as a one-way clutch for various industrial machines such as a stranded wire machine, an electric device, a printing machine, an automobile part, an electrical accessory, and a construction machine.

It is a vertical front view of the state which built the one way clutch concerning this invention in the pulley. It is sectional drawing along the II-II line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pulley 2 Porous solid lubricant 10 One-way clutch 11 Outer ring 12 Inner ring 13 Engagement element 14 Cage 15 Elastic member 16 Cylindrical surface 17 Cylindrical surface 18 Bearing fitting surface 19 Bearing 20 Seal 21 Pocket 22 Accommodating recess

Claims (5)

A one-way clutch for lubricating a friction engagement surface of an engagement member of a mechanical one-way clutch with a porous solid lubricant,
The one-way clutch characterized in that the porous solid lubricant is a solid material in which a lubricating component and a resin component are essential components, and the resin component is foamed and cured to be porous.   The mechanical one-way clutch is arranged with an outer ring, an inner ring rotatable relative to the outer ring, and a circumferential interval between the outer ring and the inner ring, and the outer ring and the inner ring are relatively rotated in one direction. A plurality of engaging members that engage with the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring to couple the two wheels, a cage that holds each engaging member, and the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. The one-way clutch according to claim 1, further comprising an elastic member that is biased in a direction in which the porous solid lubricant is engaged, wherein the porous solid lubricant is sealed between the outer ring and the inner ring.   3. The porous solid lubricant according to claim 1, wherein the porous solid lubricant comprises a resin component having rubber elasticity or a resin component made of rubber, and has a leaching property of the lubricant component due to deformation by an external force. Direction clutch.   The one-way clutch according to claim 1, 2 or 3, wherein the resin component is a polyurethane resin.   The one-way clutch according to any one of claims 1 to 4, wherein an open cell ratio of the solid matter is 50% or more.

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