JP2002168253A - Electrocorrosion-preventive rolling-element bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrocorrosion-preventive rolling-element bearing of which the bearing interference is time-variably stable without the occurrence of a creep deformation of an insulating film caused by a bearing load, even if in long time use under high temperature conditions. SOLUTION: In the electrocorrosion-preventive rolling-element bearing having the insulating film 4 on the surface of a race, the insulating film is made of a resin having a permanent distortion of not more than 2 percent under heat-up and pressurization conditions wherein the pressure of 20 MPa is applied for 24 hours at 120 deg.C. As another configuration of the bearing, the insulating film 4 is made of a resin composition having 30 to 80 capacity percent of a polyphenylene-sulfide resin, 5 to 65 capacity percent of a polyamide-imide resin and 5 to 50 capacity percent of an insulating inorganic substance. The insulating film 4 is formed so as to preferably coat at least either peripheral surface of an outer ring 2 or the internal peripheral surface of an inner ring of the race comprising the inner ring 1 and the outer ring 2, and also to preferably coat at least the side face of either of the inner ring or the outer ring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-corrosion rolling bearing having an insulating film on the surface of a bearing ring.

[0002]

2. Description of the Related Art Conventionally, in rolling bearings such as ball bearings and rolling bearings, an insulating film is formed on the surface of the race to prevent an electrolytic corrosion phenomenon occurring between the race and the rolling element. The current flowing into the bearing ring is cut off (Japanese Utility Model Laid-Open No. 2-85016).

As an anti-corrosion rolling bearing having such an insulating film, Japanese Patent Application Laid-Open No. 3-277818 discloses a polyphenylene sulfide resin containing glass fibers (hereinafter referred to as a "polyphenylene sulfide").
Abbreviated as PPS. )), With actual coating
No. 89953 discloses a material using a thermoplastic resin such as polyamide resin or PPS as a film material.

[0004] These are formed by forming a highly insulating resin film on the surface of the bearing ring, so that they have a stable function of preventing electrolytic corrosion. Further, since the film is integrally formed with the bearing ring by injection molding, the formability is improved. Film can be formed at low cost.

[0005]

However, in the above-described conventional anti-corrosion rolling bearing, when used for a long time at a high temperature exceeding, for example, 100 ° C., the insulating film may creep due to the bearing load. In other words, when used at a high temperature for a long time, there is a problem that the interference of the bearing is reduced with time.

Incidentally, when a bearing is mounted on a shaft or a housing, a shaft to which a rotational load is applied is usually fixed by "tight fit". In order to do
It is necessary to give an interference to the fitting surface between the bearing ring and the shaft or the housing.

In general, the maximum interference is 1/1000 or less of the shaft diameter or the outer diameter. As described above, when the interference decreases with the lapse of time, the fitting surface of the bearing in the radial direction, the axial direction, and the rotational direction. Relative motion may occur, causing undesirable problems such as wear on the mating surfaces.

Although it is theoretically possible to form an insulating film with a small thickness to reduce the change over time of the interference,
For example, it is not easy to form a resin insulating film having a thickness of about 0.2 mm with a uniform thickness. This is because the filling of the resin into the mold becomes defective due to the high melt viscosity of the resin. In fact, if the thickness of the insulating film is not more than 0.3 mm, it is easy to break or it is difficult to form a uniform thickness. Did not.

As shown in FIG. 4, an anti-corrosion rolling bearing 12 used for an electric railway vehicle electric motor and its rotational force transmission mechanism is used as an anti-corrosion rolling bearing which is used for a long time under a condition where a large load is applied. , 13 and there is a demand for a rolling bearing applicable to such an application.

Further, the creep resistance of the insulating film can be improved by adding glass fibers to PPS, which is a material for forming the insulating film, but the creep resistance is not sufficiently improved if the glass fiber content can maintain the injection moldability. Could not improve.

Further, since PPS is a resin having a glass transition point (Tg) at around 90 ° C., the use durability of a bearing made of a PPS composition deteriorates at a high temperature higher than Tg of PPS.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to provide an insulating film formed on the surface of a bearing ring with good creep resistance, and to set the interference of the bearing for a long time even under high temperature and high load conditions. An object of the present invention is to provide an anti-corrosion rolling bearing that is stable over time and rotates smoothly.

In particular, an object of the present invention is to prevent the insulating film from creep deformation due to a high bearing load even when used for a long time at a high temperature exceeding the glass transition point of PPS. An object of the present invention is to provide an anti-corrosion rolling bearing in which the interference of the bearing is stable over time even under use conditions, and rotates smoothly.

Further, as an anti-corrosion rolling bearing which is used for a long time under a condition where a heavy load is applied, it is also possible to provide an anti-corrosion rolling bearing which can be applied particularly to a rotating force transmission mechanism from an electric motor of an electric railway vehicle. It is an object of the present invention.

[0015]

SUMMARY OF THE INVENTION In order to solve the problem of providing an anti-corrosion rolling bearing in which the interference of the bearing is stable with time as described above, in the present invention,
In an anti-corrosion rolling bearing having an insulating film on the surface of a raceway, the insulating film is made of a resin having a permanent set of 2% or less due to compression under heating and pressing conditions of applying a pressure of 20 MPa at 120 ° C. for 24 hours. Therefore, the anti-corrosion rolling bearing was used.

As described above, when the insulating film is formed with a resin having a permanent set by compression of 2% or less under the predetermined heating and pressurizing conditions, the interference of the bearing is sufficiently stable with time to provide an anti-corrosion rolling bearing. Even when repeatedly exposed to high temperatures, the size of the gap between the outer diameter surface and the housing does not change, and the tightening bolt of the bearing retaining ring on the width surface does not loosen, and the tightness of the bearing becomes stable over time. Thus, the anti-corrosion rolling bearing smoothly rotates.

Conversely, when an insulating film is formed of a resin having a permanent set due to compression exceeding 2% under predetermined heating and pressing conditions,
It is necessary to form the insulation film considerably thicker, and the interference of the bearing changes, causing rattling,
Thereby, abrasion easily occurs on the fitting surface.

Further, in an anti-corrosion rolling bearing having an insulating film on the surface of a raceway, the problem that the PPS insulating film is deformed when used for a long time at a high temperature exceeding the glass transition point of the PPS resin is solved. In order to perform the above, the insulating film is made of polyphenylene sulfide resin (PPS) 30
It was formed of a resin composition containing 〜80% by volume and 5-65% by volume of a polyamideimide resin.

Rolling bearings having an insulating film formed of a resin composition containing PPS and a polyamideimide resin have excellent creep resistance, especially at high temperatures, as compared with conventional PPS-based insulating films. However, the anti-corrosion rolling bearing becomes sufficiently stable over time.

A rolling bearing in which an insulating film is formed from a resin composition containing a predetermined amount of a polyamideimide resin has fluidity such that the resin composition can be injection-molded in a molten state.
An insulating film can be formed on the main part of the bearing by composite molding, and can be manufactured efficiently.

In order to solve the above-mentioned problems in a conventional anti-corrosion rolling bearing having an insulating film made of a PPS resin composition, the present invention relates to an anti-corrosion rolling bearing having an insulating film on the surface of a raceway. An anti-corrosion rolling bearing characterized in that the coating is formed of a resin composition containing 30 to 80% by volume of a polyphenylene sulfide resin, 5 to 65% by volume of a polyamideimide resin and 5 to 50% by volume of an insulating inorganic substance. It is.

An anti-corrosion rolling bearing having an insulating film made of the above resin composition is particularly excellent in creep resistance at high temperatures, and provides a stable anti-corrosion rolling bearing with a good interference with time. Become.

The insulating film in such an anti-corrosion rolling bearing is provided on the outer race and the inner race of the inner race of at least one of the outer race and the inner race of the inner race of the races composed of the outer race and the inner race.
It is preferable to use an insulating film formed so as to cover at least one side surface of the outer ring in order to reliably obtain the desired effect of stabilizing the interference of the bearing with time.

The anti-corrosion rolling bearing constructed as described above can be used for an electric motor of an electric railway vehicle or its rotational force transmission mechanism or both, even when electricity flows through the rotating shaft of the electric motor. Electric leakage does not occur to the metal parts constituting the rotational force transmission mechanism or the rails of the railway, so that the anti-corrosion rolling bearing meets the expectation of the anti-corrosion property.

That is, the above-described anti-corrosion rolling bearing is an anti-corrosion rolling bearing used for a motor of an electric railway vehicle or a rotational force transmission mechanism thereof, particularly for supporting a rotating shaft of a main electric motor (motor) of an electric locomotive. It can be applied as an anti-corrosion rolling bearing.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

The embodiment shown in FIG. 1 and FIG.
An anti-corrosion rolling bearing in which an insulating film 4 is formed by injection molding on the surface of a raceway comprising an outer ring 2 and an outer ring 2. That is, circumferential grooves 3, 3 'are formed on the surface (outer peripheral surface and side surfaces) of the outer ring 2 by machining, and an insulating film 4 having a constant thickness is formed thereon by injection molding to form a cylindrical roller bearing. It was created.

As shown in FIG. 2, the insulating film 4 which is a ring-shaped injection molded body has a circumferential groove 3 of the outer ring 2 on its inner peripheral side.
It has a ridge 5 or an annular protrusion 5 'that can be fitted to 3', and engages with the circumferential grooves 3, 3 'to prevent the insulating film 4 from shifting in the axial and radial directions. are doing. In FIG. 1, reference numeral 6 denotes a "roller" of a rolling element, reference numeral 7 denotes a housing, reference numerals 8 and 9 denote retainers, and reference numeral 10 denotes a ring for preventing the bearing from coming off.

The object on which the insulating film is formed may be one or both of the inner ring 1 and the outer ring 2.
It is preferable that at least one of the outer peripheral surface and the inner peripheral surface of the inner ring 1 and at least one side surface of the inner and outer rings be covered. Types of bearings include ball bearings,
Any of a roller bearing, a radial bearing and a thrust bearing may be employed.

As shown in FIG. 4, the anti-corrosion rolling bearing provided with the insulating film is a rolling bearing 12, 1 supporting a rotating shaft of an electric motor of a railway car.
3 is used at a key point of a rotational force transmission mechanism. 4 indicates an axle, 15 and 16 indicate gears, and 17 indicates wheels.

The heat-resistant resin material for forming the insulating film according to the present invention will be described below. As described later, as the resin material for forming the insulating film, in addition to PPS, polyamide imide resin (hereinafter abbreviated as PAI), aromatic polyether ketone resin, polycyano ether resin, thermoplastic polyimide resin, and the like Is mentioned. These mixing ratios are set to 30 for the same reason as in the case of PPS described later.
８０80% by volume.

P used in the material for forming the insulating film of the present invention
PS is represented by the following chemical formula 1.

[0033]

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A particularly typical PPS is represented by the following chemical formula 2.

[0035]

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This resin is commercially available from Philips Petroleum Corporation in the United States under the trademark "Ryton" and its production method is described in US Pat. No. 3,354,129 (corresponding to Japanese Patent Publication No. 45-33).
No. 68). According to the description of the publication, Ryton is 160-250 in N-methylpyrrolidone solvent.
It is manufactured by reacting p-dichlorobenzene and sodium disulfide under the conditions of ℃ and pressurized, and has various degrees of polymerization ranging from those with no cross-linking to those with partial cross-linking in the resin. Can be freely subjected to a post-heat treatment step, so that those having an appropriate melt viscosity characteristic for a target solvent blend can be arbitrarily selected and used. Further, the PPS used in the present invention may be a linear PPS without having a crosslinked structure.

The mixing ratio of PPS constituting the insulating film is as follows:
30 to 80% by volume. If the amount of the PPS is less than 30% by volume, it is difficult to make use of the inherent insulation properties and moldability of the PPS. If the amount is more than 80% by volume, the creep resistance at high temperatures due to other predetermined components will be reduced. This is because the improvement cannot be sufficiently performed.

The polyamideimide resin (hereinafter abbreviated as PAI) used in the present invention is represented by the following formula (3), wherein R1 is an aromatic group containing at least one benzene ring. Is a compound in which two carbonyl groups are bonded to adjacent carbon atoms in the benzene ring of R1. And the P used in the present invention
AI may be a copolymer with a compound containing such a structure and another amide bond.

[0039]

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(In the formula, R ₁ represents a trivalent aromatic group containing at least one benzene ring, R ₂ represents a divalent organic group, and R ₃ represents hydrogen, a methyl group or a phenyl group.) Examples of desirable R ₁ in the three formulas are as shown in the following chemical formula 4.

[0041]

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Examples of desirable R ₂ in the chemical formula ( ₃ ) include — (CH ₂ ) _m — (wherein m is a saturated aliphatic hydrocarbon group of 4 to 12), and the following chemical formula (5). There is something.

[0043]

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(In the general formula of the group shown in Chemical formula 5, Y is 1 to
3 integers, X ₄ is an aliphatic hydrocarbon group or an aromatic group having 1 to 6 carbon atoms. In addition, it is more preferable to copolymerize a unit having the following structure with these PAI resins from the viewpoint of improving the compatibility with PPS and further improving the melt fluidity.

[0045]

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[0046]

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Ar _{1 in} the formula (6) is a divalent aromatic group, and specific examples thereof include those shown in the following formula (8).

[0048]

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R1 in the formula is a divalent aliphatic group, and specific examples thereof include-(CH ₂ ) m
-. More preferred — (CH ₂ ) m — is m = 2 to 12, and particularly preferred is m
= 4-12.

The copolymer comprising the structure represented by the chemical formula (3) and the structure represented by the chemical formula (6) is preferably a compound represented by the formula (3): Those having a composition in which Chemical Formula 6 comprises 90 to 30 mol% are preferred.

Further, the copolymer comprising the structure represented by the chemical formula (3) and the structure represented by the chemical formula (7) is preferably a compound represented by the formula (3):
A composition having a composition of 50 mol% and 90 to 50 mol% is preferable.

The copolymer having the structure represented by Chemical Formula 3, Chemical Formula 6, or Chemical Formula 7 has a composition comprising 10 to 70 mol% of Chemical Formula 3, 1 to 89 mol% of Chemical Formula 6, and 1 to 70 mol% of Chemical Formula 7. Are preferred. The arrangement of each structure in the above copolymer may be any of random, block or alternating.

Such a method for producing PAI is well known as disclosed in patent publications such as US Pat. No. 3,625,911 and Japanese Patent Publication No. 50-33120.
For example, an aromatic tricarboxylic acid anhydride or a derivative thereof as shown in the following chemical formula 9 and H ₂ N—R ₂ —NH ₂ , OCN—R ₂
-NCO, (wherein R ₂ is the same as described in Chemical formula 3 or Chemical formula 4 above) and an organic diamine or a derivative thereof, and a polar solvent such as dimethylacetamide, dimethylformamide or N-methylpyrrolidone. A polyamic acid is produced by reacting at a predetermined temperature in an organic solvent for a required time, and this is converted into an imidized state by heating or other methods.

[0054]

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As the PAI produced by this method, there is a PAI represented by the following formula (10), and a commercially available product thereof is Torlon (registered trademark) manufactured by Amoco, USA.

[0056]

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Since the PAI obtained by the above method is inferior in melt fluidity, it is preferable to adopt a method of producing from aromatic tricarboxylic anhydride and diisocyanate in order to obtain PAI having better fluidity. Also,
At the time of polymerization, it is more preferable to carry out the reaction under conditions such that the amidation and the imidation proceed stepwise as shown in JP-A-6-322060.

For the purpose of improving the compatibility between PAI and PPS, a precursor of polyamideimide may be used, or an isocyanate compound may be added as a third component.

The mixing ratio of PAI constituting the insulating film is as follows:
5 to 65% by volume. If the amount of the PAI is less than 5% by volume, the creep resistance at high temperatures cannot be sufficiently improved.
It becomes difficult to make full use of the insulation properties and easiness of molding of PPS, which is another component, and the fluidity in a molten state is reduced, making injection molding difficult.

Next, the aromatic polyetherketone resin (hereinafter abbreviated as PEK) used in the present invention is a polymer comprising a repeating unit represented by the following formula (11), or such a repeating unit. Together with a repeating unit represented by the following formula
It is a copolymer polymerized so as not to lose its original properties.

[0061]

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[0062]

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As a commercially available product of such PEK, VICTREX (VICTRE)
X) manufactured by PEEK, manufactured by VICTREX represented by the following formula: PEK, or manufactured by BASF expressed by the following formula: Ultr
apek. These can be produced according to well-known methods described in JP-A-54-90296 and the like in addition to the above-mentioned commercially available products.

[0064]

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[0065]

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[0066]

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Next, the polycyano aryl ether resin (hereinafter abbreviated as PEN) used in the present invention is a polymer comprising a repeating unit represented by the following formula (16), or a polymer represented by the following formula (17) together with the above repeating unit. Is a polymer coexisting with a repeating unit represented by the following formula at a ratio of about 20 mol% or less so as not to impair the intrinsic properties of PEN.

[0068]

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[0069]

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Such a PEN preferably has a reduced viscosity (η7sp / C) at 60 ° C. of a 0.2 g / dl concentration solution in which p-chlorophenol is used as a solvent is 0.3 g / dl or more. These are commercially available from Idemitsu Kosan as polyether nitrile (ID300). In addition,
The method for producing PEN is disclosed in Examples of JP-A-63-3059.

The thermoplastic polyimide resin used in the present invention
Is a heavy chain having a repeating unit structure shown in the above formula (18).
And is represented by the following chemical formula 19 as a diamine component.
Using ether diamine and one or more
Polyamide obtained by reacting with carboxylic dianhydride
It is obtained by dehydrating and cyclizing an acid. Of which R ₁
~ R_FourAre all hydrogen atoms, and a particularly typical one is
Marketed under the trademark "AURUM"
The manufacturing method is described in JP-A-61-143478,
JP-A-62-68817, JP-A-62-86021
It is well known in the gazette and the like.

[0072]

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(Wherein X represents a group selected from the group consisting of a direct bond, a hydrocarbon group having 1 to 10 carbon atoms, a hexafluorinated isopropylidene group, a carbonyl group, a thio group and a sulfone group; R _{1 to} R ₄ represent hydrogen, a lower alkyl group having 1 to 5 carbon atoms, a lower alkoxy group having 1 to 5 carbon atoms, chlorine or bromine, and may be the same or different, and Y is the number of carbon atoms. 4 selected from the group consisting of two or more aliphatic groups, cycloaliphatic groups, monocyclic aromatic groups, and non-fused polycyclic aromatic groups in which the aromatic groups are connected to each other directly or by a bridging member; Represents a valence group.)

[0074]

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Since this thermoplastic polyimide resin exhibits thermoplasticity while maintaining the heat resistance inherent in the polyimide resin,
It can be formed relatively easily by compression molding, injection molding, extrusion molding or other melt molding methods.

The following are specific examples of the diamine represented by the above formula. That is, bis (4- (3-aminophenoxy) phenyl] methane, l, l-bis [4- (3-aminophenoxy) phenyl] ethane, l, 2-bis [4- (3-aminophenoxy) phenyl] Ethane, 2,2-bis [4- (3-
Aminophenoxy) phenyl] propane, 2- [4-
(3-aminophenoxy) phenyl] -2- [4- (3
-Aminophenoxy) -3-methylphenyl] propane, 2,2-bis [4- (3-aminophenoxy) -3
-Methylphenyl] propane, 2- [4- (3-aminophenoxy) phenyl] -2- [4- (3-aminophenoxy) -3,5-dimethylphenyl] propane, 2,
2-bis [4- (3-aminophenoxy) -3,5-dimethylphenyl] propane, 2,2-bis [4- (3-
Aminophenoxy) phenyl] butane, 2,2-bis [4- (3-aminophenoxy) phenyl-1,1,
1,3,3,3-hexafluoropropane, 4,4'-
Bis (3-aminophenoxy) biphenyl, 4,4'-
Bis (3-aminophenoxy) -3-methylbiphenyl, 4,4'-bis (3-aminophenoxy) -3,3
'-Dimethylbiphenyl, 4,4'-bis (3-aminophenoxy) -3,5-dimethylbiphenyl, 4,4'
-Bis (3-aminophenoxy) -3,3 ', 5,5'
Tetramethylbiphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, and the like, These are used alone or in combination of two or more.

Further, other diamines may be mixed and used as long as the melt fluidity of the thermoplastic polyimide resin is not impaired. Dimethylamine which can be used in combination is, for example, m-aminobenzylamine, p-
Aminobenzylamine, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether,
4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfone, 3,
4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-
Diaminobenzophenone, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4-bis (4 -Aminophenoxy)
Benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) ketone, bis [ 4- (4-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfone, and the like. These diamines are usually mixed at a ratio of 30% or less, preferably 5% or less. Can be used.

The thermoplastic polyimide resin particularly preferably used in the present invention is obtained by reacting the diamine with tetracarboxylic dianhydride in an organic solvent and dehydrating and ring-closing. Tetracarboxylic dianhydride is represented by the following formula:
(Wherein Y is the same as Y in the above formula (2)).

[0079]

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The specific compound names of the tetracarboxylic dianhydride represented by the above formula are, for example, ethylene tetracarboxylic dianhydride, 1,2,3,4-butanetetracarboxylic dianhydride, Cyclopentanecarboxylic dianhydride, pyromellitic dianhydride, 3,3 ', 4,4'
-Benzophenonetetracarboxylic dianhydride, 2,2
', 3,3'-benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-biphenyltetracarboxylic dianhydride, 2,2 ', 3,3'-biphenyltetracarboxylic dianhydride Bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2′p-dicarboxyphenyl) ethane dianhydride, Screw (2,3-
Dicarboxyphenyl) methane dianhydride, bis (3,4
-Dicarboxyphenyl) methane dianhydride, 2,3
6,7-naphthalenetetracarboxylic dianhydride, l,
4,5,8-naphthalenetetracarboxylic dianhydride,
1,2,5,6-naphthalenetetracarboxylic dianhydride, l, 2,3,4-benzenetetracarboxylic dianhydride, 3,4,9,10-berylenetetracarboxylic dianhydride, 2 , 3,6,7-anthracenetetracarboxylic dianhydride, l, 2,7,8-phenanthrenetetracarboxylic dianhydride, 4,4 '-(p-phenylenedioxy) diphthalic dianhydride, , 4 '-(m-phenylenedioxy) diphthalic dianhydride and the like. These tetracarboxylic dianhydrides may be used alone or
Use more than seeds.

The insulating inorganic substance used in the present invention is as follows:
While maintaining the insulating properties of the resin composition containing a heat-resistant resin as a main component, it is compounded in order to more reliably improve the creep resistance at high temperatures, and preferred insulating inorganic substances are as follows: Is mentioned. These may be used in combination of one or more kinds, or may be subjected to a surface treatment.

That is, specific examples of the insulating inorganic substance used in the present invention include glass fiber, calcium oxide, clay, calcined clay, silica, glass sphere, aramid fiber, alumina, magnesium oxide, calcium silicate, asbestos, and aluminate. Sodium, sodium aluminosilicate, magnesium silicate, aluminum hydroxide, calcium hydroxide, barium sulfate, potassium alum, sodium alum, iron alum, shirasu balloon, glass balloon, zinc oxide, zinc oxide whisker, antimony trioxide, boric acid, Borax, zinc borate, titanium oxide,
Titanium oxide whisker, glass beads, calcium carbonate,
Examples include calcium carbonate whiskers, zinc carbonate, hydrotalcite, iron oxide, potassium titanate, potassium titanate whiskers, asbestos, aluminum borate, aluminum borate whiskers, aluminum oxide, and aluminum nitride.

The insulating inorganic material as exemplified above has a fiber diameter of 0.1 to 20 μm and a fiber length of 20 in a fibrous form.
A size of about 3,000 μm is preferable, and in the case of a granular form, a preferable result is obtained by using a particle having a size of about 100 μm.

When compounding the insulating inorganic material, a material having good heat conductivity such as aluminum oxide or aluminum nitride is selected to dissipate heat from the bearing, or the current value under an AC voltage is reduced. For this purpose, a material having a low dielectric constant may be selected.

The compounding ratio of the insulating inorganic material constituting the insulating film is 5 to 50% by volume. When the amount of the insulating inorganic material is less than 5% by volume, the improvement in creep resistance at high temperatures cannot be sufficiently improved. When the amount is more than 50% by volume, the insulation by PPS which is another component is insulated. This is because the properties and easiness of molding cannot be fully utilized, and the fluidity in the molten state decreases, making it difficult to perform injection molding.

The method of adding and mixing the raw materials of the resin composition of the present invention is not particularly limited, and a general method widely used can be adopted. For example, the resin as the main component and other raw materials are individually dry-mixed individually or after blending with a mixer such as a Henschel mixer, a ball mill, a tumbler mixer, etc., and thereafter, an injection molding machine or a melt extrusion machine having good melt-mixing properties. It is possible to employ a method of supplying the mixture to a molding machine or melt-mixing in advance using a hot roll, a kneader, a Banbury mixer, a melt extruder, or the like. Alternatively, a method may be employed in which PPS and PAI are melt-mixed in advance, then other components are mixed, and further melt-mixed.

Further, in order to mold the resin composition of the present invention, it is preferable to carry out injection molding in view of production efficiency, but other well-known molding methods may be appropriately employed. That is, in order to mold the resin composition of the present invention other than injection molding, a well-known synthetic resin molding method such as compression molding and extrusion molding, or melt-mixing of the composition, followed by jet milling, freeze milling, etc. Or a method of performing fluid immersion coating, electrostatic powder coating, or the like without classification. Further, the obtained powder can be dispersed in a solvent, and spray coating or dip coating can be performed.

[0088]

Examples and Comparative Examples The raw materials used in the examples and the comparative examples are collectively shown as follows. The numbers shown in parentheses correspond to the numbers of the raw materials in the table below, and the mixing ratios of the components in the table are all% by volume. (1) Polyamideimide resin [PAI] (under the conditions of first amidating and then imidizing using 18 mol% of trimellitic anhydride, 32 mol% of isophthalic acid, and 50 mol% of 2,4-tolylene diisocyanate as raw materials, (2) Polyamide imide resin [PAI] (50 mol% of trimellitic anhydride, 50 mol% of 2,4-tolylene diisocyanate) (Polyamide imide resin polymerized in N-methylpyrrolidone under the conditions of crystallization and imidization), (3) polyphenylene sulfide resin [PPS]
(Toprene Corporation: semi-linear type PPS T2) (4) Polyphenylene sulfide resin [PPS]
(Manufactured by Topren: Linear PPS LR-03) (5) Polyphenylene sulfide resin [PPS]
(Toppan Corporation: T4AG) (6) Glass fiber [GF] (Asahi Fiberglass Corporation:
(Chopped strand 03MA497) (7) Glass beads [GB] (manufactured by Toshiba Barotini):
EGB731APN) (8) Aluminum nitride powder [AlN] (AlN-7, manufactured by Kyoritsu Ceramics Co., Ltd.).

[Embodiments 1-4] As shown in FIG. 1, in the embodiment, the inner ring 1 of the standard type bearing is provided and the NU 21
A cylindrical roller bearing (an outer diameter of 170 mm, an inner diameter of 95 mm, and a circumferential groove 3 formed on the surface of the outer ring 2 by machining) is coated with an insulating film 4 having a constant thickness (1 mm) by injection molding. Width 32 mm). The insulating film 4 is as shown in Table 1.
Were mixed together and formed by injection molding.

As shown in FIG. 2, the insulating film 4, which is a ring-shaped molded body, has a ridge 5 on the inner peripheral side thereof which is in close contact with the circumferential groove 3 of the outer ring 2 (FIG. 1). And annular protrusions 5 'which are in close contact with the circumferential groove 3', and are engaged with each other, so that displacement of the insulating film 4 is prevented.

In order to form the insulating film 4 and a test piece for measuring the compression set described later, the raw materials were blended in the ratio (volume%) shown in Table 1 and mixed with a Henschel mixer. Machine, cylinder temperature: 280
The mixture was extruded and granulated under melt-mixing conditions at 〜340 ° C. and a rotation speed of 100 rpm, and the obtained pellets were heated at a resin temperature of 280-34.
0 ° C., injection pressure 800 kgf / cm 2, mold temperature 14
It was formed under injection molding conditions of 0 ° C. And the bearing shown in FIG. 1 and FIG. 2 was manufactured using the insulating film, and the following tests were performed. <Measurement test of compression set> A test piece for measuring compression set was obtained by injection molding a JIS No. 1 dumbbell and then measuring 4 m.
An m-cube test piece cut out by cutting was used. Then, two opposing surfaces parallel to the flow direction of the resin during injection molding were sandwiched between two stainless steel flat jigs, and pressure was applied from the outside of the jig to apply a pressure of 20 MPa to the test piece. In this state, the mixture was heated to 120 ° C., kept for 24 hours, cooled to room temperature, and depressurized. Immediately after the pressure was released, the thickness (B, mm) of the test piece in the pressing direction was measured, and the compression set was determined from the thickness (A, mm) before the test by the following equation.
Also shown in Table 1. Compression set (%) = (AB) / A × 100. <Creep resistance of bearing under high temperature conditions (change in outer diameter dimension)>
The interference of 0.3 mm in the bearing (100 ° C.) of the embodiment shown in FIGS. 1 and 2 was left at 100 ° C. for 100 hours, and after the temperature was returned to normal temperature, the change in external dimensions (μm) was measured. Are also shown in Table 1.

[0092]

[Table 1]

[Comparative Examples 1 to 4] The bearings shown in FIGS. 1 and 2 were manufactured in exactly the same manner as in the example except that the insulating film was formed with the composition shown in Table 2. The compression set and the creep resistance were examined under the conditions, and the results are shown in Table 2.

[0094]

[Table 2]

As is clear from the results shown in Tables 1 and 2, a comparative example in which an insulating film made of a resin having a compression set of more than 2% was provided under heating and pressing conditions of applying a pressure of 20 MPa at 120 ° C. for 24 hours. It can be seen that Nos. 1 to 4 have an insulating film having an insufficient tightening margin corresponding to the elapse of time left at a high temperature and having insufficient creep resistance.

On the other hand, Examples 1-4 satisfying the condition of the predetermined compression set have good injection moldability,
After a lapse of 00 hours, it was clearly advantageous in that it had better creep resistance than the comparative example.

[Examples 5 to 9] The insulating film 4 was prepared by mixing raw materials in the proportions (volume%) shown in Table 3 and mixing them with a Henschel mixer. The pellets were extruded and granulated under melt-mixing conditions of 280 to 340 ° C and a rotation speed of 100 rpm, and the obtained pellets were subjected to a resin temperature of 280 to 350 ° C, an injection pressure of 800 kgf / cm ² ,
Molding was performed under injection molding conditions at a mold temperature of 100 to 160 ° C.
Regarding ease of molding during injection molding, the result was good / bad 2
The results were evaluated on a scale, and indicated by the symbols of good (良) and bad (x) in the table.

[0098]

[Table 3]

Further, in order to evaluate the creep resistance at high temperatures, the bearings shown in FIGS. 1 and 2 were manufactured by using an insulating film, and this bearing (tightening at 120 ° C., 0.3 mm) was made 1 mm.
It was left at 20 ° C. for 3000 hours to measure the change with time of the interference of the bearing, and the results are shown in the graph of FIG.

[Comparative Examples 5 to 11] Except that the insulating film was formed with the composition shown in Table 4, the procedure was the same as that of the example.
The bearing shown in FIG. 1 was manufactured, and the formability was examined under the same conditions as in the example. The results are shown in Table 4. In Comparative Examples 6, 9, and 11, the fluidity at the time of melting was poor, and a bearing insulating layer could not be formed.

[0101]

[Table 4]

In Comparative Example 5, the time-dependent change of the interference of the bearing was measured under exactly the same conditions as in the evaluation method of creep resistance at high temperatures in the example, and the results are also shown in the graph of FIG. .

As apparent from the results shown in Tables 3 and 4 and FIG. 3, Comparative Example 5 in which an insulating film made of a resin composition containing no PAI was provided, was tightened with the passage of time at a high temperature. It was greatly reduced, and the creep resistance was insufficient. Further, Comparative Examples 5 to 11 in which the mixing ratios of PPS, PAI and the insulating inorganic substance were out of the predetermined range,
The injection moldability and the creep resistance at high temperatures were not simultaneously satisfied.

On the other hand, Examples 5 to 9 satisfying the predetermined compounding ratio are clearly advantageous in that they have good injection moldability and are more excellent in creep resistance than Comparative Examples after 3000 hours. there were.

[0105]

As described above, of the invention according to each of the claims of the present application, an insulating film made of a resin having a compression set of 2% or less under heating and pressing conditions of applying a pressure of 20 MPa at 120 ° C. for 24 hours. The anti-corrosion rolling bearings are provided with a good resistance to creep of the insulating film formed on the surface of the bearing ring, and the tightness of the bearing is stable over time for a long time even under conditions of high temperature and high load, allowing smooth rotation. There is an advantage that the anti-corrosion rolling bearing is used.

Among the inventions according to the claims of the present application, PPS
Anti-corrosion rolling bearings with an insulating coating formed by a resin composition containing a polyamideimide resin and a polyamide-imide resin. There is an advantage that an anti-corrosion rolling bearing in which the interference of the bearing stabilizes over time under the use conditions.

A rolling bearing having an insulating film formed of a resin composition containing a predetermined amount of a polyamideimide resin has fluidity that can be injection-molded in a molten state, and also has moldability.

In addition to the above composition materials, insulating inorganic substances 5
An anti-corrosion rolling bearing having an insulating film made of a resin composition to which 50% by volume has been added has extremely excellent creep resistance at high temperatures, and has a very good interference with time and a stable anti-corrosion rolling. Become a bearing.

The anti-corrosion rolling bearing having the above-mentioned advantages is particularly suitable for electric corrosion, and is used for a long time under the condition that a large load is applied. The present invention can be applied to a mechanism, particularly an anti-corrosion rolling bearing for supporting a rotating shaft of a main motor of an electric locomotive.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a state in which a rolling bearing according to an embodiment is attached to a housing.

FIG. 2 is a cross-sectional view of an insulating film coated on the outer ring surface of a rolling bearing.

FIG. 3 is a table showing the relationship between the interference of rolling bearings of Examples and Comparative Examples and a high-temperature leaving time.

FIG. 4 is an explanatory view of a main part of the electric railway vehicle showing a use state of the anti-corrosion rolling bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3, 3 'circumferential groove 4 Insulating film 5 Ridge 5' Annular protrusion 6 Roller 7 Housing 8, 9 Cage 10 Ring 11 Electric motor 12, 13 Rolling bearing 14 Axle 15, 16 Gear 17 Wheel

Claims (5)

[Claims] 1. An anti-corrosion rolling bearing having an insulating film on the surface of a raceway, wherein the insulating film has a thickness of 2 degrees at 120 ° C.
An anti-corrosion rolling bearing, characterized in that it is an insulating film made of a resin having a compression set of 2% or less under a heating and pressurizing condition of applying a pressure of 0 MPa for 24 hours. 2. An anti-corrosion rolling bearing having an insulating film on the surface of a raceway, wherein the insulating film is a resin composition containing 30 to 80% by volume of a polyphenylene sulfide resin and 5 to 65% by volume of a polyamideimide resin. An anti-corrosion rolling bearing characterized by being formed. 3. An anti-corrosion rolling bearing having an insulating film on the surface of a raceway, wherein the insulating film is formed of 30 to 80% by volume of a polyphenylene sulfide resin, 5 to 65% by volume of a polyamideimide resin, and 5 to 50% of an insulating inorganic substance. capacity%
An anti-corrosion rolling bearing formed of a resin composition containing: 4. An insulating film is formed so as to cover at least one of an outer peripheral surface of an outer ring and an inner peripheral surface of an inner ring and at least one side surface of an inner / outer ring in a raceway including an outer ring and an inner ring. The anti-corrosion rolling bearing according to any one of claims 1 to 3, which is an insulating film. 5. The anti-corrosion rolling bearing according to claim 1, wherein the anti-corrosion rolling bearing is an anti-corrosion rolling bearing used for an electric motor of an electric railway vehicle or a torque transmitting mechanism thereof.