JP2005155892A - Seal member for rolling device, and rolling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seal member for a rolling device having sealing performance equal to or higher than that of a conventional seal member by using a plasticizer free from endocrine disrupters, and contributing on environment conservation, and to provide the rolling device having superior sealing performance. <P>SOLUTION: In this contact type seal member mounted on a sealing device of the rolling device, composed of an elastic material, and shaped integrally with a cored bar, the elastic member is a rubber composition including a glycol ester plasticizer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to automobile electrical components, alternators and intermediate pulleys that are engine auxiliary machines, electromagnetic clutches for car air conditioners, water pumps, hub units, electromagnetic clutches for gas heat pumps, compressors, linear guide devices, rolling devices such as ball screws, etc. The present invention relates to a contact-type seal member to be mounted on the sealing device and a rolling device including the seal member.

  A contact-type seal member mounted on a sealing device of the rolling device is generally formed by integrally molding an elastic member having a seal lip portion that comes into contact with a mating member such as a race or a shaft, and a cored bar. ing. In addition, the elastic member contains a plasticizer in consideration of the followability of the seal lip portion to the mating member and the like, and is provided with appropriate flexibility.

  Conventional plasticizers that give flexibility to plastics and rubber and improve processability include di- (2-ethylhexyl) phthalate (DOP), dibutyl phthalate (DBP), diethyl phthalate (DEP), butyl benzyl. Phthalate (BBP) and di- (2-ethylhexyl) adipate are widely used around the world. In Japan, phthalates account for over 80% of the total plasticizer production, and have been used without any particular problems. I have been. These plasticizers are generally used for elastic members as well (see, for example, Patent Document 1 and Patent Document 2).

  However, in recent years, interest in environmental issues has increased, and so-called 'environmental hormones' have attracted attention, and di- (2-ethylhexyl) phthalate (DOP) and dibutyl phthalate (DBP), which have been widely used so far, have been attracting attention. ), Diethyl phthalate (DEP), butyl benzyl phthalate (BBP), and di- (2-ethylhexyl) adipate may be environmental hormones and have a concern of polluting the environment.

Japanese Patent No. 3318772 Japanese Patent Laid-Open No. 2003-268159

  In view of the above situation, an object of the present invention is to provide a rolling device seal member having a sealing performance equal to or higher than that of a conventional seal member using a plasticizer that is not suspected of being an environmental hormone. Another object of the present invention is to provide a rolling device that includes the rolling device seal member and contributes to environmental conservation and is excellent in sealing performance.

  In order to achieve the above object, the present invention provides a contact-type sealing member that is attached to a sealing device of a rolling device and is formed of an elastic material and is integrally formed with a cored bar, wherein the elastic member is a glycol ester. Provided is a rolling device seal member comprising a rubber composition containing a plasticizer.

  In the sealing member for a rolling device according to the present invention, the glycol ester plasticizer to be used is not an environmental hormone but contributes to environmental conservation and has a sealing performance equal to or higher than that of the conventional one. Further, the rolling device provided with this rolling device seal member is also free from environmental pollution and has excellent sealing performance.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a rolling device seal member (hereinafter simply referred to as “seal member”) and a rolling device according to the present invention will be described in detail below by taking a rolling bearing with a seal and a rolling bearing for a wheel as examples.

  FIG. 1 is a sectional view showing an example of a rolling bearing with a seal. In the illustrated rolling bearing 20 with a seal, a plurality of rolling elements 24 are held between an inner ring 21 and an outer ring 22 via a cage 23 so as to be freely rotatable, and further provided on the inner surface of the outer ring 22. A seal member 30 is fixed to the retaining groove 25 and is roughly configured. The seal member 30 is formed by integrally forming a ring-shaped cored bar 31 having a flange part on the outer periphery and an elastic member 32 on the outer side thereof. An annular main portion 33 composed of the elastic member, a caulking portion 34 composed of a flange portion of the core metal 31 and an elastic member on the outside thereof, and latched in the retaining groove 25 of the outer ring 22; The lip portion 35 is made of an elastic member on the inner peripheral side and contacts a receiving groove 26 provided on the outer peripheral surface of the inner ring 21. In the seal member 30, a steel plate such as SPCC or SECC is generally used as the core metal 31, and in the present invention, the elastic member 32 is made of an elastic material described later.

  FIG. 2 is a cross-sectional view showing an example of a wheel rolling bearing. Rolling bearings for wheels that support the wheels of automobiles and railway vehicles are usually used outdoors while being exposed to rainwater, wind and snow, and dust. In extreme cases, it may be used while immersed in water. Thus, the wheel rolling bearing has a sealing structure as illustrated. In the wheel rolling bearing unit O, the outer ring equivalent member 1 that is a fixed ring is supported and fixed to the suspension device by a mounting portion 2 formed on the outer peripheral surface thereof. Therefore, the outer ring equivalent member 1 does not rotate during use. Inside the outer ring equivalent member 1, an inner ring equivalent member 3 as a rotating ring is provided concentrically with the outer ring equivalent member 1, and the inner ring equivalent member 3 is rotated during use. The inner ring equivalent member 3 includes a hub 4 and an inner ring 5. A spline groove 6 is formed on the inner peripheral surface of the hub 4, and a mounting flange 7 is formed on the outer peripheral surface of the outer end (referred to as an end on the outer side in the width direction when assembled to the vehicle, left end in FIG. 2). doing. A drive shaft that is rotationally driven through a constant velocity joint is inserted into the spline groove 6 when assembled to the vehicle, and a wheel is fixed to the mounting flange 7. Double row outer ring raceways 8, 8 are formed on the inner peripheral surface of the outer ring equivalent member 1, and inner ring raceways 9, 9 are formed on the outer peripheral surface of the intermediate portion of the hub 4 and the outer peripheral surface of the inner ring 5, respectively. Then, rolling elements 10 are provided between the outer ring raceways 8 and 8 and the inner ring raceways 9 and 9 to freely rotate the inner ring equivalent member 3 inside the outer ring equivalent member 1. Moreover, in order to hold | maintain the rolling element 10.10 so that rolling is possible, the holder | retainers 11 and 11 are provided. In the illustrated example, a ball is used as the rolling element 10.10. However, in the case of a vehicle bearing that is heavy, a tapered roller may be used as the rolling element. Further, sealing devices 12 a and 12 b are provided between the outer end portion of the outer ring equivalent member 1 and the intermediate portion outer peripheral surface of the hub 4, and between the inner peripheral surface of the outer ring equivalent member 1 and the outer peripheral surface of the inner ring equivalent member 3. Thus, the outer end opening of the space 13 in which the rolling elements 10.10 are installed is closed.

  Next, the structure of the sealing devices 12a and 12b will be described in detail with reference to FIGS. First, the sealing device 12 a shown in FIG. 3 includes a cored bar 105, a slinger 106, and an elastic member 107. Of these, the cored bar 106 is integrally formed by subjecting a metal plate such as a low carbon steel plate to punching processing such as press processing and plastic processing. Such a metal core 106 includes an outer diameter side cylindrical portion 109 that can be fitted and fixed to the inner peripheral surface of the end portion of the outer ring equivalent member 1 constituting the wheel rolling bearing 0, and an axially inner side of the outer diameter side cylindrical portion 109. The inner ring portion 110 is bent inward in the diameter direction from the end edge (the left end edge in FIG. 3), and has an approximately L-shaped cross section and an annular shape. Further, the slinger 106 is integrally formed by subjecting a metal plate having excellent corrosion resistance, such as a stainless steel plate, to punching processing such as press processing and plastic processing. Such a slinger 106 includes an inner diameter side cylindrical portion 112 that can be fitted and fixed to the outer peripheral surface of the outer end portion of the inner ring 5 constituting the wheel rolling bearing 0, and an outer edge in the axial direction of the inner diameter side cylindrical portion 112 (see FIG. 3 right end edge) and an outer ring portion 113 bent outward in the diameter direction, and having an annular shape with an L-shaped cross section. The elastic member 107 is made of an elastic material, which will be described later. The elastic member 107 includes three seal lips 114, 115, and 116 on the outer side, the middle side, and the inner side. Then, the outer edge of the outer seal lip 114 located on the outermost side is brought into sliding contact with the inner surface of the outer ring portion 113 constituting the slinger 106, and the intermediate seal lip 115 and the inner seal lip 116, which are the remaining two seal lips. The tip edge of the inner sleeve is slidably contacted with the outer peripheral surface of the inner diameter side cylindrical portion 112 constituting the slinger 106, thereby preventing leakage of grease from the inside and introducing dust, water, muddy water, etc. from the outside into the bearing. Prevent intrusion.

  The sealing device 12b shown in FIG. 4 includes a cored bar 216 and an elastic member 217, each of which is formed in an annular shape. Of these, the core metal 216 is made of a metal plate and is fitted and fixed to the outer end of the outer ring equivalent member 1. The elastic member 217 is made of an elastic material to be described later, and is bonded and fixed to the core metal 216 by adhesion or the like. The elastic member 217 includes an outer diameter side, an inner diameter side, two side seal lips 218 and 219, and one radial seal lip 220. Then, the two side seal lips 218 and 219 are inclined toward the outer side in the diametrical direction (upward in FIG. 4) toward the tip edge (the left end edge in FIG. 4), thereby allowing foreign matter to enter the space 13. The entry prevention function is secured. Further, the radial seal lip 220 is inclined in the direction toward the inner side (right side in FIG. 4) of the space 13 toward the tip edge (lower right edge in FIG. 4), thereby ensuring the grease leakage prevention function. . More specifically, the sealing device 12b includes a cored bar 216 and an elastic member 217 each formed in a ring shape. The cored bar 216 of the sealing device 12b is integrally formed by subjecting a metal plate such as a low carbon steel plate to punching processing such as press processing and plastic processing. The metal core 216 includes an outer diameter side cylindrical portion 222 that can be fitted and fixed to the inner peripheral surface of the end portion of the outer ring equivalent member 1 constituting the wheel rolling bearing 0, and an outer edge of the outer diameter side cylindrical portion 222 (see FIG. 4 and the support plate part 223 bent inward in the diameter direction. Of these, the outer diameter side cylindrical portion 222 is composed of a large diameter portion 224 and an elastic member 217 closer to the inner end (rightward in FIG. 4) and the outer side surface (left side in FIG. The outer peripheral edge of the elastic member 217 is sandwiched between the outer peripheral surface of the inclined portion 217 continuous from the fitting cylinder portion 222 and the inner peripheral surface of the opening end portion of the outer ring equivalent member 1. And by this structure, the fitting part of the metal core 216 and the outer ring equivalent member 1 is sealed. The outer diameter of the large diameter portion 224 in the free state is slightly larger than the inner diameter of the outer end opening of the outer ring equivalent member 1. Accordingly, the large-diameter portion 224 can be fitted and fixed to the outer end opening of the outer ring equivalent member 1 by an interference fit. Further, the support plate portion 223 has a substantially S-shaped cross-sectional shape, and approaches the rolling elements 10 and 10 installed in the space 13 as it goes inward in the diameter direction (downward in FIG. 4) (right side in FIG. 4). Direction). On the other hand, the outer peripheral edge portion of the elastic member 217 constituting the sealing device 12 b together with the core metal 216 covers the outer peripheral surface of the inclined portion 227. The outer diameter in a free state of a part of the elastic member 217 that covers the outer peripheral surface of the inclined portion 227 is slightly larger than the inner diameter of the outer end opening of the outer ring equivalent member 1. Therefore, in a state where the large-diameter portion 224 is fitted and fixed to the outer end opening, the portion of the elastic member 217 covering the outer peripheral surface of the inclined portion 227 is the outer peripheral surface of the inclined portion 227 and the outer end. It is elastically pressed with the inner peripheral surface of the opening to ensure the sealing performance of the part. Further, the base portion 226 of the elastic member 217 completely covers the outer surface (left side surface in FIG. 4) of the support plate portion 223 over the entire circumference. Then, an outer diameter side, an inner diameter side, two side seal lips 218 and 219, and one radial seal lip 220 are formed on the outer surface and inner peripheral edge of the base 226. The two side seal lips 218 and 219 are inclined toward the outer side in the diametrical direction (upward in FIG. 4) toward the tip edge (left end edge in FIG. 4), thereby preventing foreign matter from entering the space 13. The function is secured. Further, the radial seal lip 220 is inclined in the direction toward the inner side (right side in FIG. 4) of the space 13 toward the tip edge (lower right edge in FIG. 4), thereby ensuring the grease leakage prevention function. .

  Further, wheel rolling bearings are currently classified and called as first generation, second generation, and third generation depending on the degree of unitization with mating members around the bearing, but the present invention can also be applied to these. . Here, the first generation hub unit bearing is illustrated in FIG. 5, and the second generation hub unit bearing is illustrated in FIGS.

  FIG. 5 illustrates a double row angular contact ball bearing in which the outer ring of the back combination bearing is integrated as the first generation hub unit 500. As shown in the drawing, the inner ring 501 and the outer ring 502 are formed with raceways in two rows, respectively, and balls 503 that are rolling elements are held by a common cage 504 so as to be able to roll. In order to seal the gap between the outer ring 502 and the inner ring 501, for example, the sealing device 12a shown in FIG.

  6 to 8 illustrate a double-row angular contact ball bearing in which the outer ring of the back combination bearing is integrated as the second generation hub unit 600. FIG. 6 shows a double-row angular contact ball bearing 600 for an outer ring rotating type driven wheel. A spindle (not shown) is inserted into the inner ring 601 and tightened by a nut (not shown). Further, the outer ring 602 has an integrated flange and is configured to be fixed to a wheel and a disc brake (not shown) by a hub bolt 610. 3 is fixed to both ends of the flanged outer ring 502 in order to seal the gap between the inner ring 601 and the like, for example.

  FIG. 7 shows a double-row angular contact ball bearing 600 for an inner ring rotating type driven wheel. A hub spindle (not shown) is press-fitted into the inner ring 601 and tightened by a nut (not shown). Further, the outer ring 602 is integrated with a flange and is configured to be fixed to a vehicle body (not shown). 3 is fixed to both ends of the flanged outer ring 602 in order to seal the gap between the inner ring 601 and the like, for example.

  FIG. 8 shows a double row angular contact ball bearing 600 for an inner ring rotating type drive wheel. A wheel hub and a drive shaft (not shown) are engaged with the inner ring 601. In addition, the outer ring 602 is integrated with a flange and is configured to be fixed to an axle housing (not shown). 3 is fixed to both ends of the flanged outer ring 602 in order to seal the gap between the inner ring 601 and the like, for example.

  Each of the above elastic members is composed of a rubber composition, but synthetic rubber is used as a base rubber. Among them, acrylonitrile butadiene rubber (nitrile rubber, NBR), acrylic rubber, fluorine, etc. in consideration of heat resistance, oil resistance, grease resistance, etc. Rubber is preferred, and acrylonitrile butadiene rubber is particularly preferred. In addition, hydrogenated acrylonitrile butadiene rubber obtained by hydrogenating this acrylonitrile butadiene rubber, acrylonitrile butadiene isoprene rubber obtained by copolymerization of isoprene, carboxylated acrylonitrile butadiene rubber introduced with a carboxyl group in the molecule, and hydrogenated carboxylated hydrogenation Various modified acrylonitrile butadiene rubbers such as acrylonitrile butadiene rubber can also be used. These base rubbers can be used in combination of two or more.

  In addition, the content of acrylonitrile in the acrylonitrile butadiene rubber is not limited at times, and is classified into low nitrile, medium nitrile, medium high nitrile, high nitrile, and extremely high nitrile in ascending order of content. Considering properties such as wear resistance, wear resistance, creep resistance, and lip followability, medium nitrile, medium high nitrile, and high nitrile are preferable, and the acrylonitrile content in that case is 20 to 40% by mass. More preferably, the acrylonitrile content is 25 to 36% by mass, and in this range, a well-balanced characteristic is exhibited. When the amount of acrylonitrile is less than 20% by mass, the wear resistance is inferior, the seal lip is easily worn, and as a result, the seal life is shortened. When the amount of acrylonitrile exceeds 40% by mass, the compression set characteristics are inferior, the followability of the lip portion is deteriorated, and as a result, the seal life is shortened.

  In the base rubber, a glycol ester plasticizer is blended in order to provide followability of the elastic member. This glycol ester plasticizer has no doubt of environmental hormone, and di- (2-ethylhexyl) phthalate (DOP), dibutyl phthalate (DBP), diethyl phthalate (DEP), butyl benzyl phthalate (BBP) Seal performance equal to or better than when di- (2-ethylhexyl) adipate is used. Examples of the glycol ester plasticizer include polyethylene glycol 200 monolaurate, polyethylene glycol 400 monolaurate, polyethylene glycol 600 monolaurate, polyethylene glycol 400 dilaurate, and the like. Further, the addition amount of the glycol ester plasticizer is 1 to 50 parts by weight, more preferably 3 to 30 parts by weight with respect to 100 parts by weight of the base rubber.

  Also, a plasticizer for rubber that is not suspected of being an environmental hormone can be used in combination. Specifically, dimethyl phthalate, di-n-octyl phthalate, diheptyl phthalate, diisodecyl phthalate, diundecyl phthalate, di (heptyl, undecyl) phthalate, diisononyl phthalate, di-normal alkyl phthalate, alkyl・ Benzyl phthalate, dialkyl phthalate, dibutoxyethyl phthalate, dibutoxyethoxyethyl phthalate, dibutoxyethoxyethyl phthalate, dimethyl cyclohexyl phthalate, ethyl phthalyl ethyl glycolate, butyl phthalyl butyl Glycolate, tetrahydrophthalic acid derivatives, dibutyl adipate, dimethyl adipate, diisodecyl adipate, diisobutyl adipate, di (n-octyl, n-decyl) a Dipetate, diisononyl adipate, diisooctyl adipate, benzyloctyl adipate, dibutyl diglycol adipate, di-n-alkyl adipate, alkylalkyl ether diester adipate, dibutoxyethyl adipate, di- (butoxy ethoxy ethyl) ) Adipate, di (n-haesyl, n-octyl, n-decyl) adipate, azelaic acid derivative, sebacic acid derivative, dodecane-2-acid derivative, maleic acid derivative, fumaric acid derivative, trimellitic acid derivative, pyromellitic acid Derivatives, citric acid derivatives, oleic acid derivatives, ricinoleic acid derivatives, stearic acid derivatives, polyoxyethylene laurate, polyoxyethylene laurate emulsions, polyhydric alcohol fatty acid esters, sulfonic acid derivatives, phosphoric acid derivatives, glucose Tar acid derivative, dipentaerythritol ester, glycol derivative, glycerin derivative, epoxy derivative, polyester plasticizer, polyether plasticizer, polyether ester plasticizer, ether thioether, ester thioester, stearic ester amide N, N-dimethyloleamide, N, N-dimethylcaprylamide / capramide, liquid rubber and the like can be used in combination. Among them, sulfonic acid derivatives are preferable, and specific examples include alkylsulfonic acid phenyl esters (commercially available “Mezamol” manufactured by Bayer). By the sulfonic acid group, better plastic efficiency, low temperature property and mechanical performance can be obtained. Further, cyclohexene dicarboxylic acid ester using diisononyl phthalate ("Monosizer W-621" manufactured by Dainippon Ink & Chemicals, Inc., a commercially available product) is also preferable because of its low viscosity, good plastic efficiency, and excellent low temperature properties. . In addition, the addition amount of these plasticizers is selected in consideration of the addition amount of the glycol ester plasticizer.

  Reinforcing materials, fillers, vulcanizing additives, anti-aging agents, processing aids, etc. can be added to the rubber composition, and if necessary, such as wear improvers, lubricants, lubricating oils, etc. Various additives can also be added. These details are described below.

  Carbon black is blended as a reinforcing material. There are no particular restrictions on the type, for example, SAF (Super Abrasion Furnace Black), ISAF (Intermediate Super Abrasion Furnace Black), MAF (Medium Abrasion Furnace Black), FEF (Fast Extruding Furnace Black), GPF (General Purpose Furnace Black), SRF (Simi-Reinforcing Furnace Black), FT (Fine Thermal Furnace Black), MT (Medium Thermal Furnace Black) and the like. Of these, HAF, MAF, FEF, GPF, and SRF, which are excellent in balance between reinforcement and moldability, are preferred, and FEF, GPF, and SRF are particularly preferred. The compounding amount of carbon black is 20 to 90 parts by weight with respect to 100 parts by weight of the base rubber. When the amount is less than 20 parts by weight, sufficient reinforcing properties are not exhibited. When the amount is more than 90 parts by weight, the hardness of the rubber composition increases and the elongation decreases, and the inherent rubber elasticity decreases.

Silicic acid and silicate are also added as reinforcing materials. As suitable silicic acid and silicate, natural silica powder / silica stone powder (SiO ₂ ), synthetic silicic anhydride (SiO ₂ ), synthetic hydrous silicic acid (SiO ₂ .nH ₂ O), etc. kaolin clay is aluminum silicates _{(A1 2 0 3 · 2SiO 2} · 2 H 2 O), calcined clay _{(A1 2 0 3 · 2SiO 2} ), pyrophyllite _{(A1 2 0 3 · 4 SiO} 2 · H 2 O) , Sericite (K ₂ O · 3 A1 ₂ 0 ₃ · 6 SiO ₂ · 2 H ₂ O), mica (K ₂ O · 3 A1 ₂ 0 ₃ · 6 SiO ₂ · 2 H ₂ O), nepheline cinite ( _{Na 2 O · K 2 O ·} A1 2 0 3 · 2SiO 2), a hydrous aluminum silicate _{(A1 2 0 3 · mSiO 2} · mH 2 O) , etc., the magnesium silicates talc (3MgO · 4 SiO ₂ · H ₂ O) and the like, and calcium silicates include wollastonite (CaO · SiO ₂ ) and the like. Among these, aluminum silicates are preferable in consideration of wear resistance and the like. These silicates may be used alone or in combination. The compounding amount of these silicic acids or silicates is 20 to 150 parts by weight with respect to 100 parts by weight of the base rubber. If it is less than 20 parts by weight, sufficient reinforcing properties will not be exhibited, and if it is more than 150 parts by weight, the hardness of the rubber material composition will increase and the elongation will decrease, and the inherent rubber elasticity will decrease. .

  Carbon black can be used in combination with silicic acid or silicate. In this case, the compounding amount is 10 to 90 parts by weight of carbon black and 10 parts of silicic acid or silicate with respect to 100 parts by weight of the base rubber. To 110 parts by weight and a total of 20 to 200 parts by weight, more preferably 20 to 80 parts by weight of carbon black, 20 to 100 parts by weight of silicic acid or silicate, and a total amount of 60 Part by weight to 120 parts by weight.

  As a crosslinking additive, a vulcanizing agent (crosslinking agent), a vulcanization aid, and a vulcanization acceleration aid are blended. Vulcanizing agents include sulfur, such as powdered sulfur, sulfur white, precipitated sulfur, highly dispersible sulfur, morpholine disulfide, alkylphenol disulfide, N, N-dithiobis (hexahydro-2H-azepinone-2), thiuram polysulfide, etc. Examples include sulfur compounds that can be discharged, peroxides such as dicumyl peroxide, di (t-butylperoxy) diisopropylbenzene, 2,5-dimethylhexane, and benzoyl peroxide. Among them, it is preferable to use highly dispersible sulfur or morpholine disulfide in terms of dispersibility, ease of handling, and heat resistance.

  When a sulfur vulcanizing agent is used, guanidine compounds, aldehyde-ammonia compounds, thiazole compounds, thiourea compounds, sulfenamide compounds, thiuram compounds, dithiocarbamate compounds, xanthate compounds, etc. It is necessary to use it together as a vulcanization aid. When using highly dispersible sulfur among sulfur-based vulcanizing agents, thiuram-based tetramethylthiuram disulfide or the like, or sulfenamide-based N-cyclobenzyl-2-benzothiazyl sulfenamide and the like and thiazole-based vulcanizing agents It is preferable to use 2-mercaptoben ヅ thiazole or the like together.

  Examples of the vulcanization acceleration aid include metal oxides such as zinc oxide, metal carbonates, metal hydroxides, organic acids such as stearic acid and derivatives thereof, and amines. Two or more of these vulcanizing glazes and activators may be mixed and used, and usually 0.1 to 10 parts by weight per 100 parts by weight of the base rubber. In the case of using carboxylated acrylonitrile butadiene rubber, it is preferable to use zinc peroxide and stearic acid together because zinc oxide tends to cause early vulcanization. Zinc peroxide is present in the composition as it is at the temperature at which the acrylonitrile butadiene rubber composition is kneaded and produces zinc oxide at the time of vulcanization molding. Absent.

  Moreover, when using an organic peroxide type | system | group vulcanizing agent, a crosslinking adjuvant (coagent) can also be used together. Examples of the crosslinking aid include tetrahydrofurfuryl methacrylate, ethylene dimethacrylate, 1,3-butylene dimethacrylate, 1,4-methylene dimethacrylate, 1,6-hexanediol dimethacrylate, polyethylene glycol dimethacrylate, 1 , 4-Butanediol diacrylate, 1,6-hexanediol diacrylate, 2,2'-bis (4-methacryloxydiethoxyphenyl) propane, 2,2'-hist <4-acryloxyjetoxyphenyl> Propane, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol triacrylate, 3-chloro-2-hydroxypropyl methacrylate, oligoester acrylate, aluminum (meth) acrylate, zinc (meth) acrylate , Magnesium (meth) acrylate, calcium (meth) acrylate, triallyl isocyanurate, triallyl cyanurate, triallyl trimellitate, diallyl phthalate, diallyl chlorendate, divinylbenzene, 2-vinylpyridine, N, N Examples include '-methylenebisacrylamide, P-quinone dioxime, p, p'-dibenzoylquinone dioxime, 1,2-polybutadiene, and metal methacrylate. The amount of these crosslinking aids is 1 to 10 parts by weight per 100 parts by weight of the base rubber.

  Anti-aging agent is mix | blended in order to suppress deterioration of an elastic member. Preferable anti-aging agents include amine / ketone condensation products, aromatic secondary amines, monophenol derivatives, bis or polyphenol derivatives, hydroquinone derivatives, sulfur-based anti-aging agents, phosphorus-based anti-aging agents, and the like. Among them, 2,2,4-trimethyl-1,2-dihydroquinoline polymer of amine-ketone condensation product system, condensation reaction product of diphenylamine and acetone, N, N'-di of aromatic secondary amine system -Β-naphthyl-P-phenylenediamine, 4,4'-bis- (α, α-dimethylbenzyl) diphenylamine, N-phenyl-N '-(3-methacryloyloxy-2-hydroxypropyl) -P-phenylene Diamine and the like are preferable. The amount of the anti-aging agent is 0.5 to 20 parts by weight based on 100 parts by weight of the base rubber.

  In order to prevent thermal decomposition and improve heat resistance, it is more preferable to use a secondary anti-aging agent together with the anti-aging agent. Examples of the secondary antiaging agent include sulfur-based 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, and zinc salts thereof. The compounding amount of the secondary anti-aging agent is 0.5 to 20 parts by weight with respect to 100 parts by weight of the base rubber.

  Further, as a sunlight crack preventing agent that suppresses cracking due to the action of sunlight or ozone, about 0.5 to 2 parts by weight of a wax having a melting point of about 55 to 70 ° C. may be added to 100 parts by weight of the base rubber.

  Examples of the wear improver include polyolefin particles and spherical carbon fine particles. Specific examples of polyolefin particles include polyethylene and polypropylene particles, and more preferably, particles made of carboxyl-modified polyethylene (maleic anhydride-modified polyethylene) and carboxyl-modified polypropylene (maleic anhydride-modified polypropylene). It is done. When polyethylene and polypropylene are carboxyl-modified, they easily adsorb to various rubbers, oxides and the like due to the carboxyl group in the structure. In addition, when the base rubber is a carboxyl-modified nitrile rubber, the carboxyl groups present therein have the same effect, and these synergistic effects result in mechanical strength such as tensile strength, wear resistance, and bending fatigue resistance. It is thought that it will improve further. The addition amount of the polyolefin particles is preferably 10 to 60 parts by weight with respect to 100 parts by weight of the base rubber from the balance between the wear resistance of the rubber composition and other physical properties. If it is less than 10 parts by weight, the effect of improving the wear resistance is low. On the other hand, if it exceeds 60 parts by weight, the hardness of the rubber composition will increase and the elongation will decrease, and the rubber elasticity will decrease.

  Processing aids and lubricants may be known ones, and any known coupling agents, pigments, dyes, release agents and the like can be added.

  In terms of physical properties, the hardness of the rubber composition is affected by the blending amount of the various additives listed above, but in accordance with JIS K 6301 due to hermeticity when applied to a wheel rolling bearing seal device. In the spring hardness A scale described, a range of 50 to 90 is preferable. When the hardness is less than 50, the friction resistance of the sealing device increases and the wear resistance decreases. Also, if the hardness exceeds 90, the rubber elasticity will decrease as described above, so the sealing performance and followability of the lip part of the sealing device will decrease, and it will be used in environments where there is a lot of dust and seawater. Then, the life of the rolling bearing may be reduced.

  A method for obtaining a rubber composition as a raw material for an elastic member using each of the above components is not particularly limited, and a base rubber and an additive are conventionally known, such as a rubber kneading roll, a pressure kneader, a Banbury mixer, and the like. It is possible to knead evenly using a rubber kneading apparatus. The kneading conditions are not particularly limited, but normally, various additives can be sufficiently dispersed by kneading at a temperature of 30 to 80 ° C. for 5 to 60 minutes.

  Further, the method for making the rubber composition as an elastic member of the sealing device is not particularly limited, but it may be heated while pressing the unvulcanized rubber composition in a mold, compression molding, transfer molding, It can be produced by a known rubber molding method such as injection molding. For example, in the case of compression molding, an unvulcanized rubber composition sheet manufactured by the above-described method by inserting a core metal (formation of the core part of the sealing device) previously coated with an adhesive into a mold And can be produced by pressure vulcanization usually at 120 to 200 ° C. for about 30 seconds to 30 minutes. Moreover, you may post-crosslink at 120-200 degreeC for about 10 minutes-10 hours as needed.

  Furthermore, in the rolling device of the present invention, it is preferable that parts other than the above-described seal member, for example, a cage and grease, do not contain a chemical substance suspected of being an environmental hormone.

  EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited to the examples.

(Examples 1-9, Comparative Examples 1-3)
As shown in Table 1, each material was put into a rubber kneading roll and uniformly kneaded to prepare a rubber composition.

(1) Physical property measurement
A 2 mm-thick sheet molding die was mounted on a hot press heated to 180 ° C., and a sheet made of the uncrosslinked rubber composition was placed thereon. Then, it was heated for 15 minutes and pressurized at a pressure of 30 kgf / cm ² to obtain a vulcanized rubber sheet having a length of 150 mm, a width of 150 mm, and a thickness of 2 mm. Table 2 shows the hardness based on 100% tensile strength at room temperature and JIS K6301 (spring hardness A scale) of the rubber sheet thus prepared.

(2) Bearing rotation test Using the rubber compositions of Examples and Comparative Examples, a rolling bearing with a seal having the structure shown in FIG. 1 was produced. In other words, the rubber composition is integrally vulcanized and molded on the outside of the SPCC mandrel to form a seal member, which is made up of an inner ring and an outer ring of a 6203 (nominal number) single row deep groove ball bearing made by NSK Ltd. The test bearings were assembled by inserting them in between and adding ether grease. Then, this test bearing was rotated under the following conditions by a bearing rotation tester manufactured by Nippon Seiko Co., Ltd., and the time when the frequency of the bearing doubled was defined as the life (endurance time). The respective durability times are shown in Table 2 as relative values when the life time of Comparative Example 1 is 1.
・ 10,000rpm
・ Rotation for 1,000 hours ・ Enclosed grease: Ether grease ・ Ambient temperature: 80 ℃

(3) Muddy water immersion test Using the rubber compositions of Examples and Comparative Examples, a sealing device having a structure shown in FIG. 3 (inner diameter 60 mm) was prepared, and this was incorporated into the hub unit bearing shown in FIG. Grease was sealed to obtain a test bearing. Then, this test bearing is incorporated into a hub unit seal unit rotation tester manufactured by NSK Ltd., the shaft is rotated with muddy water injected to the center of the shaft, the seal becomes defective, and the muddy water is introduced to the opposite side. The time until the infiltration of water was confirmed (durability time) was measured to evaluate the sealing performance. In addition, the presence or absence of water intrusion was detected when water entered and energized to a leakage sensor attached to the atmosphere side. The test conditions are as follows. The respective durability times are shown in Table 3 as relative values when the lifetime of Comparative Example 1 is 1.
・ Rotation speed: 1000rpm
-Shaft eccentricity: 0.5mm TIR
・ Muddy water composition: JIS 8 class dust 20%
・ Enclosed grease: Urea compound, mineral oil ・ Grease application amount: 0.35 g

  As is clear from Tables 2 and 3, the sealing member using the plasticizer of the present invention is a conventional di- (2-ethylhexyl) phthalate (DOP), dibutyl phthalate (DBP), diethyl phthalate as the plasticizer. (DEP), butyl benzyl phthalate (BBP), and di- (2-ethylhexyl) adipate. Moreover, it is suitable also for the 1st generation and 2nd generation hub unit bearings as shown in FIGS.

  As mentioned above, although the rolling bearing and the hub unit bearing were mainly illustrated and demonstrated regarding this invention, this invention is applicable not only to this but seal members, such as a linear guide apparatus and a ball screw.

It is sectional drawing which shows an example of a rolling bearing with a seal. It is sectional drawing which shows an example of the rolling bearing for wheels. It is an enlarged view of one sealing device (12a) of the rolling bearing for wheels shown in FIG. It is an enlarged view of the other sealing device (12b) of the rolling bearing for wheels shown in FIG. It is sectional drawing which shows an example of a 1st generation hub unit bearing. It is sectional drawing which shows an example of a 2nd generation hub unit bearing. It is sectional drawing which shows the other example of a 2nd generation hub unit bearing. It is sectional drawing which shows the further another example of a 2nd generation hub unit bearing.

Explanation of symbols

O Rolling bearing 1 Outer ring equivalent member 4 Inner ring equivalent member 10 Rolling body 11 Retainer 12a Sealing device 12b Sealing device 20 Rolling bearing with seal 21 Inner ring 22 Outer ring 23 Retainer 24 Rolling body 30 Seal member 31 Core metal 32 Elastic member 35 Lip portion 105 Core 106 Slinger 107 Elastic member 217 Elastic member

Claims (2)

  A contact-type sealing member that is mounted on a sealing device of a rolling device and is made of an elastic material and molded integrally with a core metal, wherein the elastic member is made of a rubber composition containing a glycol ester plasticizer. A rolling device sealing member.   A rolling device comprising the rolling device seal member according to claim 1.

Images