JP5293281B2 - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing improved in reliability, including a cage improved in toughness, maintaining heat resistance and chemical resistance particular to a polyphenylene sulfide resin. <P>SOLUTION: In the rolling bearing including at least an inner ring, an outer ring, the cage made of a polyphenylene sulfide resin, the cage made of the synthetic resin, and a rolling body, the cage made of the synthetic resin is formed of a polyphenylene sulfide resin composition containing a toughness agent, which is composed of a core shell type rubber polymer with a vinyl polymer having an epoxy group as a shell phase, and with a silicone/acrylic compound rubber as a core phase, of 3-15 mass% in relation to the whole quantity of the resin composition, and a reinforcing fiber material of 10-40 mass% in relation to the whole quantity of the resin composition. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a rolling bearing provided with a synthetic resin cage.

  As a rolling bearing for supporting a rotating shaft of a machine tool, a compressor or the like, a bearing provided with a synthetic resin cage is used. Synthetic resin cages are generally made by blending glass fiber as a reinforcing fiber material with polyamide resin such as nylon 66 or nylon 46, polyphenylene sulfide resin or the like. Among these, cages using polyphenylene sulfide resin are often used in rolling bearings used for applications requiring heat resistance and chemical resistance.

  However, cages using polyphenylene sulfide resin are inferior in toughness such as impact strength compared to cages using polyamide resin, and there is a risk of breakage such as cracks when subjected to large impacts during handling or use of bearings. is there. Therefore, for example, when used for a deep groove ball bearing which is a general rolling bearing, there is a high possibility that cracks will occur in the pocket when press-fitting into the bearing. Measures are taken.

  In order to improve the toughness of the cage using polyphenylene sulfide, the present applicant has previously added 5 toughening agents composed of an ethylene-based copolymer containing 3 to 30% of glycidyl methacrylate in the molecular structure. It has been proposed to form a cage with a polyphenylene sulfide resin composition contained at a ratio of ˜20 mass% (see Patent Document 1).

JP 2008-202781 A

  However, since the toughening agent described in Patent Document 1 is mainly composed of an ethylene-based copolymer, the heat resistance of the polyphenylene sulfide resin is impaired, and the heat resistance of the cage as a whole is lowered, resulting in performance at an initial stage. However, the toughness gradually decreases when used at high temperatures. In addition, since the ethylene-based copolymer is inferior in elasticity compared to the rubber material, it is necessary to add more to improve the impact resistance, and the amount of the polyphenylene sulfide resin is reduced accordingly, and such heat resistance is reduced. The problem is expected to become more pronounced.

  Accordingly, an object of the present invention is to provide a rolling bearing having a cage with improved toughness without impairing the heat resistance and chemical resistance of the polyphenylene sulfide resin and having excellent reliability.

In order to achieve the above object, the present invention provides the following rolling bearing.
(1) In a rolling bearing comprising at least an inner ring, an outer ring, a synthetic resin cage and rolling elements,
The synthetic resin cage is a vinyl polymer having an epoxy group and a shell phase, Ri Do silicone / acrylic composite rubber core-shell type rubber polymer having a core phase and an average particle diameter of 0.08 to 0 comprising the .6μm der Rutafu agent 3-15% by weight of the resin composition the total amount, the para-aramid fibers treated with a sizing agent from the polyphenylene sulfide resin composition containing 10-40 wt% of the resin composition the total amount A rolling bearing characterized by that.
(2) The rolling bearing according to (1) above, wherein in the silicone / acrylic composite rubber, silicone rubber: acrylic rubber = 20: 80 to 80:20 (weight ratio) .
(3) the sizing agent, urethane resins, epoxy resins, the rolling bearing of the above (1) or (2), wherein the at least one kind Bareru Tokura an acrylic resin and a bismaleimide resin.

  The toughening agent comprising a core-shell type rubber polymer used in the present invention is superior in heat resistance and elasticity as compared with toughening comprising an ethylene copolymer, so that the toughness of the polyphenylene sulfide resin can be improved even with a small amount of compounding. And a decrease in heat resistance can be suppressed. Therefore, a cage made of a polyphenylene sulfide resin composition containing a toughening agent made of a core-shell type rubber polymer is excellent in heat resistance and chemical resistance, and also has improved impact resistance. Long life.

It is sectional drawing which shows an example of a cylindrical roller bearing. It is sectional drawing which shows an example of an angular contact ball bearing. It is sectional drawing which shows an example of a deep groove ball bearing. It is sectional drawing which shows an example of a tapered roller bearing. It is a perspective view which shows the holder | retainer for cylindrical roller bearings shown in FIG. FIG. 3 is a perspective view showing a cage for the angular ball bearing shown in FIG. 2. It is a perspective view which shows the holder | retainer for deep groove ball bearings shown in FIG. It is a perspective view which shows the retainer for tapered roller bearings shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  As long as the rolling bearing of the present invention includes a synthetic resin cage, the type of bearing and the shape of the cage are not limited. For example, a cylindrical roller bearing as shown in FIG. 1 and an angular ball bearing as shown in FIG. A deep groove ball bearing as shown in FIG. 3 and a tapered roller bearing as shown in FIG. 4 can be exemplified. Each of the bearings is schematically configured by holding a plurality of rolling elements (cylindrical rollers or balls) 3 between an inner ring 1 and an outer ring 2 by a synthetic resin cage 4 described later. 5 is a synthetic resin cage for the cylindrical roller bearing shown in FIG. 1, FIG. 6 is a synthetic resin cage for the angular ball bearing shown in FIG. 2, and FIG. 7 is a deep groove ball bearing shown in FIG. FIG. 8 shows a synthetic resin cage for the tapered roller bearing shown in FIG.

  Each synthetic resin cage 4 is a core shell having a polyphenylene sulfide resin having excellent heat resistance and chemical resistance as a base material, a vinyl polymer having an epoxy group as a shell phase, and a silicone / acrylic composite rubber as a core phase. A polyphenylene sulfide resin composition formed by blending a toughening agent made of a mold rubber polymer and a reinforcing fiber material is formed into a predetermined shape. The molding method can follow a normal resin molding method, but injection molding is preferred from the viewpoint of productivity.

  Since the core phase of the toughening agent is a rubber-based material, it has high elasticity, and the toughness improving effect of the polyphenylene sulfide resin is great. Moreover, both silicone rubber and acrylic rubber have the advantage of excellent heat resistance. The ratio of silicone rubber to acrylic rubber in the silicone / acrylic composite rubber is silicone rubber: acrylic rubber = 20: 80 to 80:20 (weight ratio) in terms of impact resistance, heat resistance, surface appearance of the cage, etc. Preferably there is.

  The monomers forming the acrylic rubber include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, alkyl acrylates such as 2-ethylhexyl acrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, n- Illustrative of polyfunctional (meth) acrylates such as alkyl methacrylates such as lauryl methacrylate, allyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate Can be, but is not limited to. These may be used alone or in combination of two or more.

  On the other hand, since the shell phase has high adhesiveness to the polyphenylene sulfide resin and has an epoxy group, the bonding strength between the core phase and the polyphenylene sulfide resin base material is increased, and the cage becomes high in strength.

  Examples of the monomer that forms a vinyl polymer having an epoxy group include glycidyl methacrylate, glycidyl acrylate, vinyl glycidyl ether, and allyl glycidyl ether, but are not limited thereto. These may be used alone or in combination of two or more.

To obtain a toughening agent, latex monomers are prepared by polymerizing a silicone / acrylic composite rubber monomer, and then an epoxy group-containing vinyl monomer is added to the reaction system (container) for graft polymerization. By doing so, a core-shell structure of a core phase composed of a silicone / acrylic composite rubber and a shell phase composed of an epoxy group-containing vinyl copolymer is obtained. Incidentally, latex particles of the silicone / acrylic composite rubber is a 0.08~0.6μm an average particle diameter from the viewpoint of dispersibility. In addition, since the shell phase is a very thin film, the size as a toughening agent is substantially the same as the average particle size of the latex fine particles. By uniformly dispersing the toughening agent in the polyphenylene sulfide resin base material, the impact resistance of the entire cage is increased, and the surface appearance is also improved. If the average particle size of the toughening agent is finer than 0.08 μm, the dispersibility will be good, but it will be too fine to reduce the impact resistance improvement effect. On the other hand, when the average particle diameter of the toughening agent is larger than 0.6 μm, the surface appearance of the cage deteriorates.

  The toughening agent content is 3 to 15% by mass of the total amount of the polyferene sulfide resin composition, and if it is less than 3% by mass, the effect of improving the toughness of the polyphenylene sulfide resin is not sufficient, and if it exceeds 15% by mass Mechanical strength such as tensile strength, heat resistance, chemical resistance, and the like are lowered and practicality is lowered, which is not preferable. The content of the toughening agent is more preferably 5 to 10% by mass.

Moreover, para-aramid fiber is used for the reinforcing fiber material because it is excellent in tensile strength and tensile elastic modulus. As the para-aramid fiber, specifically, copolyparaphenylene-3,4'-oxydiphenylene terephthalamide obtained by copolymerizing polyparaphenylene terephthalamide and diamine as the third component to improve ductility and the like. Ru can be mentioned fibers made of. Table 1 shows the tensile strength and tensile modulus of the para-aramid fiber.

Para-aramid textiles is a tensile strength more than 2 GPa, tensile although modulus is not less than 50 GPa, it is ultra high molecular weight polyethylene fibers as the fibers with similar characteristics. However, the ultrahigh molecular weight polyethylene fiber is not preferable because it has a melting point of about 140 ° C. and is expected to soften during use.

  Moreover, it is preferable that an average fiber diameter is 6-21 micrometers, and it is more preferable that it is 8-15 micrometers. If the fiber diameter is less than 6 μm, the strength per fiber is too low to be stably produced, resulting in a significant cost increase. When the fiber diameter exceeds 21 μm, the number of fibers decreases even with the same content, and a uniform reinforcing effect cannot be obtained over the entire cage. On the other hand, the reinforcing effect increases as the fiber length increases. Therefore, pellets made of the polyphenylene sulfide resin composition used for molding are short fiber pellets (about 3 mm pellet length) in which short fibers (chopped strands) of about 1 to 3 mm are randomly dispersed, and the fibers are parallel to the pellets. It is preferable to use oriented long fiber pellets (pellet length of about 7 to 11 mm). Thereby, the fiber exists in a long state in the obtained cage, and becomes high strength.

Further, para-aramid fiber in order to improve the adhesion between the polyphenylene sulfide resin, urethane resin, epoxy resin, acrylic resin, have preferably be treated with a sizing agent Bareru obtained from bismaleimide resins.

Content of para-aramid fiber is 10-40 mass% of polyphenylene sulfide resin composition whole quantity, Preferably it is 15-30 mass%. When the content of the reinforcing fiber material is less than 10% by mass, the mechanical strength is hardly improved.

Glass fibers and carbon fibers, the retainer is worn, the inner ring 1 and outer ring 2 exposed on the surface, carry the risk of damaging the rolling elements 3, using the para-aramid fiber in terms of mechanical strength.

  Various additives may be added to the polyphenylene sulfide resin composition as necessary. Of these, antioxidants are preferred to prevent high temperature degradation due to grease and lubricating oils. For example, appropriate amounts of amine-based antioxidants, phenol-based antioxidants, phosphite-based antioxidants, sulfur-based antioxidants, etc. It is preferable to add.

  Examples of amine antioxidants include diphenylamine compounds such as 4,4 ′-(α, α-dimethylbenzyl) diphenylamine and 4,4′-dioctyldiphenylamine, N, N′-diphenyl-p-phenylenediamine, N— Isopropyl-N′-phenyl-p-phenylenediamine, N, N′-di-2-naphthyl-p-phenylenediamine, N, N′-bis (1-methylheptyl) -p-phenylenediamine, N, N ′ Examples thereof include p-phenylenediamine compounds such as -bis (1,4-dimethylpentyl) -p-phenylenediamine and N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine.

  Examples of phenolic antioxidants include 2,4-bis [(octylthio) methyl] -o-cresol, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate. ] Tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, 1,3,5-trimethyl-2,4,6-tris (3 Hindered phenol compounds such as 5-di-t-butyl-4-hydroxybenzyl) benzene and N, N′-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamide); Mention may be made of thiobisphenol compounds such as' -thiobis- (6-tert-butyl-3-methylphenol).

  Sulfur-based antioxidants include sulfur such as bis [2-methyl-4- {3-n-alkyl (C12 or C14) thiopropionyloxy} -5-t-butylphenyl] sulfide, dilauryl thiodipropionate, etc. Examples of such compounds are listed.

  Phosphite antioxidants include tris (nonyl phenyl) phosphite, diphenyl isodecyl phosphite, cyclic neopentanetetrayl bis (2,6-di-t-butylphenyl phosphite), etc. Mention may be made of phosphate ester compounds.

  In addition to the above antioxidants, hydroquinone derivatives such as 2,5-di-t-butylhydroquinone and quinoline antioxidants such as 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinone Agents can be used.

  Of the above antioxidants, aromatic amine-based antioxidants are the most suitable and most effective in preventing deterioration of the polyphenylene sulfide resin in the gear oil and the core-shell type rubber polymer used in the present invention. .

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

(Example 1 , Comparative Examples 1-4 )
As shown in Table 2, a resin composition was prepared using polyphenylene sulfide resin (L-PPS resin), a toughening agent and a reinforcing fiber material.

  The polyphenylene sulfide resin is linear and is “Fortron 0220A9” manufactured by Polyplastics Co., Ltd. The toughening agent A is a core-shell type rubber polymer having a vinyl copolymer containing an epoxy group as a shell phase and a silicone / acrylic composite rubber as a core phase. “Metablene S” manufactured by Mitsubishi Rayon Co., Ltd. -220 ". The toughening agent B is a binary copolymer of ethylene and glycidyl methacrylate, and is “Bond First E” manufactured by Sumitomo Chemical Co., Ltd.

In Comparative Example 3, the oval cross-section glass fiber as the reinforcing fiber material (Nitto Boseki Co., Ltd. "CSG3PA-820"; variant ratios 4, minor 7 [mu] m, a urethane-based sizing agent treatment) with the ratio Comparative Examples 1, 2 and 4 use a circular cross-section glass fiber (“CS03DEFT2A” manufactured by Asahi Fiber Glass Co., Ltd .; average diameter 13 μm, treated with urethane sizing agent). In Example 1 , para-aramid fiber (sizing treated copolyparaphenylene 3,4-oxydiphenylene terephthalamide, average diameter 12 μm, average length 3 mm).

  And each test piece for tensile tests and an Izod impact test was produced from each resin composition, and the tensile strength and the Izod impact strength were measured. Also, cages for cylindrical roller bearings (“NU308ET (inner diameter 40 mm, outer diameter 90 mm, width 23 mm)” manufactured by NSK Ltd.) were injection molded. The results are shown in Table 1. The results of the drop test are “○” when there are no cracks, etc., and when one of them is cracked, etc. Was marked “x”.

  The tensile test piece was immersed in a hypoid gear oil SX 85W-90 manufactured by Toyota Motor Corporation at 180 ° C. for 200 hours, and then the same tensile test was performed. And the relative value with the result before said tension test performed without being immersed was calculated | required. The results are shown in Table 2.

As shown in Table 2, by blending tough agent A according to the present invention, that see that the impact strength is improved.

(Abrasion test)
Example 1 For the angular ball bearing “65BNR10DBB (inner diameter 65 mm, outer diameter 100 mm, width 18 mm, contact angle 18 °, four-row combination)” manufactured by NSK Ltd., using the resin compositions of Comparative Examples 1 to 4 . A cage was molded. Further, as Comparative Examples 5 and 6 , a similar cage was molded using a polyphenylene sulfide resin (“Fortron 2130A1” manufactured by Polyplastics Co., Ltd.) containing 30% by mass of carbon fiber.

An angular ball bearing “65BNR10DBB” manufactured by Nippon Seiko Co., Ltd. was assembled using the molded cage and filled with MTE grease (Ba complex-ester oil grease) to obtain a test bearing. In Comparative Example 6 , the inner and outer rings were made of carbonitrided steel SHX, the others were made of SUJ2, and the rolling elements were all made of silicon nitride.

Then, the test bearing was assembled in a testing machine (preload load at the time of incorporation: 300 N) and rotated at 15000 min ⁻¹ for 1000 hours, and then the bearing was disassembled and the wear state of the outer ring guide surface was observed. The results are shown in Table 3.

  As shown in Table 3, by using an aramid fiber as the reinforcing fiber material, damage to the outer ring guide surface is reduced, and wear resistance equivalent to that of an expensive carbonitrided steel can be realized even if inexpensive SUJ2 is used.

From the above test results, according to the present invention, a toughening agent and a reinforcing fiber material comprising a core-shell type rubber polymer having a vinyl polymer having an epoxy group as a shell phase and a silicone / acrylic composite rubber as a core phase are obtained. By mix | blending, the toughness of polyphenylene sulfide resin can be improved and impact resistance can be improved, and also wear can be prevented by using a para-aramid fiber .

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Rolling element 4 Synthetic resin cage

Claims (3)

In a rolling bearing having at least an inner ring, an outer ring, a synthetic resin cage and rolling elements,
The synthetic resin cage is a vinyl polymer having an epoxy group and a shell phase, Ri Do silicone / acrylic composite rubber core-shell type rubber polymer having a core phase and an average particle diameter of 0.08 to 0 comprising the .6μm der Rutafu agent 3-15% by weight of the resin composition the total amount, the para-aramid fibers treated with a sizing agent from the polyphenylene sulfide resin composition containing 10-40 wt% of the resin composition the total amount A rolling bearing characterized by that. 2. The rolling bearing according to claim 1, wherein in the silicone / acrylic composite rubber, silicone rubber: acrylic rubber = 20: 80 to 80:20 (weight ratio) . The sizing agent, urethane resins, epoxy resins, according to claim 1 or 2 rolling bearing, wherein the at least one kind Bareru Tokura an acrylic resin and a bismaleimide resin.

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