JP2008069923A - Electric anticorrosion rolling bearing for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of electric corrosion on a raceway surface and a surface of a rolling element of a rolling bearing, by suppressing secular degradation in physical property such as a sealing characteristic (a mechanical characteristic or an electrical characteristic). <P>SOLUTION: A ceramic thermal spray coating after sealing treatment is disposed to an area which can prevent the occurrence of electric corrosion on the raceway surface and the surface of the rolling element of the rolling bearing. A sealing agent for sealing treatment contains an epoxy group-containing component and a hardening agent and does not contain a polymerizable vinyl group-containing solvent. The epoxy group-containing component is a mixture of a polyglycidyl ether compound in which the number of epoxy groups comprised in one molecule is three or more as an essential component, and containing at least one of an alkylene diglycidyl ether compound and a cycloaliphatic diepoxy compound in which the number of epoxy groups comprised in one molecule is two. A ratio of 10-80 wt.% of polyglycidyl ether compound is blended with respect to a whole epoxy group-containing component in the mixture other than the hardener. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric corrosion prevention rolling bearing for a motor used for a bearing of a motor for a railway vehicle.

  A rolling bearing used for a motor for a railway vehicle or the like may flow a current such as a return current or a motor shaft current. When a current flows through a rolling bearing, corrosion occurs at the part that becomes the current path, for example, the contact part between the rolling element and the bearing ring, and the life of the rolling bearing is significantly shortened. There is. In order to prevent the occurrence of this electric corrosion, a method is known in which an insulating film is provided on at least the surface of the outer ring or inner ring where the housing or the shaft is fitted to cut off electric current from the outside (Patent Document 1). And Patent Document 2).

When the insulating coating is a resin coating, the insulating layer is formed by a manufacturing method in which an object to be processed is inserted into a mold and an insulating resin material is injection molded. However, a resin material having a lower thermal conductivity than a metal must contain a filler having a high thermal conductivity in the resin at a high concentration in order to release heat generated during bearing operation to the housing. As a result, the melt viscosity of the resin material increases and the filling property in the mold at the time of injection molding is inferior, making it difficult to design the insulating coating layer thin, and as a result, the dimensional accuracy of the rolling bearing cannot be maintained. There was a problem.
Resin materials used for insulating coatings are generally inferior to metals in terms of mechanical properties, dimensional stability, and creep resistance at high temperatures. Ingenuity was required, and this was a cause of lowering the degree of freedom in designing rolling bearing products. Furthermore, it is necessary to prepare a dedicated injection mold for each rolling bearing product number, which is disadvantageous in terms of product manufacturing costs.
On the other hand, when the insulating coating is a thermal spray coating using a ceramic material, unlike the resin coating, the above-mentioned concerns are alleviated. In addition, since it has better heat resistance than a resin material, it can be a suitable product for rolling bearings for motors for railway vehicles, in which the temperature rise during operation is relatively severe.

  However, a thermal sprayed coating using a ceramic material has pores such as voids, gaps, and voids generated in the process of forming the coating. Some of the pores show the form of communication holes that lead from the substrate surface to the substrate substrate, and communicate the environment where the coating surface layer is in contact with the substrate on which the coating is coated. There is a phenomenon in which the gas or liquid in contact with the outside of the thermal spray coating penetrates and diffuses to the base material through this communication hole. As a result, when the thermal spray material itself deteriorates due to corrosion, or when the base substrate is carbon steel or the like, the substrate selectively deteriorates at the contact interface between the coating and the substrate, and the spray coating is bonded to the substrate. It may lose its properties and peel off. Moreover, when it is going to ensure the insulation between a rolling bearing and the housing with which this rolling bearing is fitted, a ceramic sprayed coating will be dielectrically destroyed by the above-mentioned penetration diffusion phenomenon of gas and liquid, and desired insulation resistance will be carried out. May not be exhibited. As a result, there is a concern that an electrolytic corrosion phenomenon may occur between the rolling elements of the rolling bearing used for the motor for a railway vehicle and the raceway.

  Therefore, a thermal spray coating is formed on the inner and / or outer ring of the bearing in contact with the other member, and then a sealing process is performed, and the sealing process is performed to increase the environmental barrier property of the coating to insulate the bearing. The technique has been carried out. As a general well-known sealing treatment method, a method of applying a sealing treatment agent in which a synthetic resin such as an epoxy resin, an acrylic resin, a urethane resin, a phenol resin, or a fluororesin is dissolved in an organic solvent is applied to the spray coating. There is. However, in this method, it is only applied to the surface of the sprayed coating and does not penetrate to the bottom of the pores. Therefore, when the surface of the sprayed coating is removed by grinding or polishing after the sealing treatment in order to maintain the shape (dimension) accuracy, the sealing treatment effect on the sprayed coating may be hardly expected. In addition, in the process of use, there are cases where the coating effect of the synthetic resin is worn due to minute displacement of the bearing position due to repeated vibration of the machine and temperature rise, and the effect of the sealing treatment is not sustained.

  On the other hand, attempts are often made to improve the adhesion between the metal substrate and the thermal spray coating material by applying a sealing treatment. A general thermal sprayed coating does not form a chemical bond with the surface on which the coating is to be formed, but a mechanical fastening force (referred to as an anchoring effect, anchoring effect, etc.) and the base material. Consistency of contact. In particular, when spraying is applied to the surface of a machine part that requires a dimensional accuracy such as a rolling bearing of a motor for a railway vehicle, the surface of the machine part is often finished by polishing, and the surface roughness Ra is low. It is often less than 1 μm. Therefore, when spraying the surfaces of these metal parts, a process of increasing the surface roughness Ra to about 1 μm or more is often performed by a known surface modification method such as shot blasting or tumbling. This technique can improve the adhesion between the thermal spray coating and the substrate to some extent, but depending on the degree of surface modification, the dimensional accuracy of the substrate may deteriorate or the surface layer may be annealed. Defects such as deterioration of physical properties of the base material may occur. As a result, there is a limit to the method for improving the adhesion by this method.

  Therefore, efforts have been made to use chemical adhesion in combination to assist physical adhesion. However, in the general sealing treatment method described above, the coating is only applied to the surface of the sprayed coating. Since it does not penetrate to the base material interface at the bottom of the hole, it only increases the adhesion between the ceramic particles near the outermost surface of the thermal spray coating, and the chemical adhesion between the metal base and the thermal spray coating material. There is a problem that it cannot reach its full potential.

As a method for improving these, for example, a method of using a photocurable resin that is cured by visible light as a sealing agent (Patent Document 3), an electrodeposition coating, and an electrophoretic phenomenon of coating particles, the fineness of a sprayed coating is reduced. A method of depositing and filling the pores (Patent Document 4), a thermal spray material added with B ₂ O ₃ forming a vitreous material is sprayed on the surface of the base material, and then the thermal spray coating is heated to form B ₂ O ₃ is melted and filled in the gap generated in the sprayed coating (Patent Document 5), and a coating is formed by adding B ₂ O ₃ that forms a vitreous substance in the sprayed material, followed by heating. Known is one in which molten B ₂ O ₃ performs pore filling in the treatment (Patent Document 5). However, these methods have a problem that they are not suitable for industrial production methods, such as requiring special equipment and complicated steps in addition to the pressurization or decompression step.
Japanese Patent No. 3736486 Utility Model Registration No. 2560391 JP-A-5-106014 JP-A-6-212391 JP-A-10-259469

  The present invention has been made in order to cope with such problems, and has excellent permeability and filling ability to pores (gap), and sealing treatment is performed until substantially all gaps of the thermal spray coating material are filled. Railway vehicles that can be applied and prevent deterioration of physical properties such as sealing characteristics (mechanical characteristics, electrical characteristics) over time, preventing the occurrence of electrolytic corrosion on the raceway surface of rolling bearings and the surface of rolling elements The purpose of the present invention is to provide an electric corrosion-preventing rolling bearing for a motor that can be used for a motor for a motor.

The electric corrosion-preventing rolling bearing for a motor of the present invention is a ceramic sprayed coating that is sealed in a portion that can prevent the occurrence of electrolytic corrosion that occurs on the raceway surface and rolling element surface of a rolling bearing used in a motor for a railway vehicle. Have The sealing agent for sealing treatment contains an epoxy group-containing component and a curing agent, does not contain a polymerizable vinyl group-containing solvent, and the epoxy group-containing component is the number of epoxy groups contained in one molecule. Is a mixture containing 3 or more polyglycidyl ether compounds as an essential component and containing at least one selected from alkylene diglycidyl ether compounds and cycloaliphatic diepoxy compounds having two epoxy groups in one molecule. Yes, it is a sealing agent in which the polyglycidyl ether compound is blended in an amount of 10 to 80% by weight with respect to the entire epoxy group-containing component excluding the curing agent.
In addition, the portion that can prevent the occurrence of electrolytic corrosion in a motorized electric corrosion-preventing rolling bearing having a ceramic sprayed coating that has been sealed is that the rolling bearing and at least the housing or the shaft are fitted to each other. Features.
In addition, the epoxy group-containing component constituting the sealing agent for sealing treatment is characterized by further containing a monoglycidyl ether compound having one epoxy group in one molecule.

  The electric corrosion-preventing rolling bearing for motor of the present invention uses the predetermined sealing treatment agent as a sealing treatment agent for sealing the ceramic spray coating, so that the pores (gap) of the spray coating are closely packed. can do. Therefore, the adhesion between the base material and the thermal spray coating is improved, and further, moisture in the air is prevented from entering, and the insulation resistance value and withstand voltage characteristics are reduced without reducing the intrinsic value of the oxide ceramic thermal spray coating. Can be suppressed. As a result, the electric corrosion prevention rolling bearing for a motor of the present invention can suppress electric current transmission that causes electric corrosion over a long period of time, and has a high electric corrosion prevention effect for a long period of time.

An example of the electric corrosion prevention rolling bearing for a motor will be described with reference to FIG.
FIG. 1 is a partial cross-sectional view of an electric corrosion-preventing cylindrical roller bearing for a motor in which a ceramic sprayed coating that has been sealed is formed on the outer peripheral surface of an outer ring, which is a surface that fits with a housing.
As shown in FIG. 1, the electric corrosion prevention rolling bearing for a motor has a plurality of roller-like rolling elements 4 held by a cage 3 between an inner ring 1 and an outer ring 2, and the outer ring 2 is connected to a housing 5 or the like. The ceramic sprayed coating 7 is formed on the outer peripheral surface 2 a of the outer ring 2 and is sealed to fix the shaft 6 to the inner diameter of the inner ring 1. The inner ring 1, the outer ring 2 and the rolling element 4 are made of a metal material such as bearing steel.
The ceramic sprayed coating 7 that has been subjected to the sealing treatment is a surface that fits with the housing 5, for example, an outer diameter surface a of the outer ring 2, a surface in the range from the outer diameter surface a to the width surface b, and including the chamfered portion c. Formed.

Further, the coating 7 may be formed on the inner peripheral surface 1 a of the inner ring 1 in addition to the outer peripheral surface 2 a of the outer ring 2. In the present invention, the inner peripheral surface 1a of the inner ring 1 is at least the entire surface in a range where the inner ring 1 contacts the shaft 6 and the like.
As described above, the insulating performance is ensured by forming the ceramic sprayed coating 7 sealed on at least one of the surface where the outer ring and the housing contact, and the surface where the inner ring and the shaft contact, Electric corrosion can be prevented.

Another example of the electric corrosion prevention rolling bearing for a motor is shown in FIG. FIG. 2 is a cross-sectional view of an electric corrosion-preventing deep groove ball bearing for a motor in which a ceramic sprayed coating that has been sealed is formed in addition to the rolling surfaces of the inner and outer rings.
As shown in FIG. 2, the electric corrosion prevention deep groove ball bearing for a motor has a plurality of ball-shaped rolling elements 4a held between an inner ring 1 and an outer ring 2, and the outer ring 2 is a housing or the like (not shown). And a ceramic sprayed coating 7 which is sealed on the outer peripheral surface of the outer ring 2 and the inner peripheral surface of the inner ring 1. The inner ring 1, the outer ring 2 and the rolling element 4a are made of a metal material such as bearing steel. 3 is a cage, 3a is a sealing member, and 3b is grease.

A method for forming the ceramic sprayed coating 7 that has been sealed on the outer peripheral surface of the outer ring will be described with reference to FIG. The coating 7 is formed by first forming a sprayed ceramic coating on the outer peripheral surface 2a of the outer ring 2 by a spraying method.
The sprayed ceramic coating is formed by forming a sprayed material such as oxide ceramics or carbide cermet on the surface of a base metal such as steel by a known spraying method.
Examples of the oxide ceramic used as the thermal spray material include alumina, zirconia, and titania, and examples of the carbide cermet include chromium carbide and tungsten carbide.
In forming the thermal sprayed ceramic coating, a metal powder such as nickel can be sprayed on the lowermost layer in order to improve the adhesion between the thermal spray coating and the base metal. Moreover, a metal film can be formed in the outermost layer for the purpose of relieving the external mechanical impact which a thermal spraying ceramic film receives.
As the spraying method, for example, a plasma spraying method, a high-speed gas flame spraying method, or the like can be used. The film thickness of the thermal spray coating can be appropriately set according to the type of the thermal spray material and the use of the resulting thermal spray coating coating member, but usually when carbon steel is the base material and the thermal spray material is alumina, 20 ~ It is about 2000 μm, preferably about 50 to 1000 μm.

In the sealing treatment to the ceramic sprayed coating, the penetration and filling properties of the sealing agent are affected by the particle boundary fusion structure forming the sprayed coating to be processed. For this reason, it is desirable to select an optimal sealing treatment agent suitable for the particle boundary fusion structure of the thermal spray coating and the required characteristics of the thermal spray coating after sealing.
For example, the sealing agent used in the present invention to be described later is preferably used for sealing treatment when the formed sprayed coating has a porosity of 10% or less. The sealing agent should be used for sealing when the porosity of the sprayed coating formed by plasma spraying or high-speed gas flame spraying method using ceramic powder or carbide cermet as the spraying material is 10% or less. Is preferred. When these thermal spray coatings are subjected to a sealing treatment using the sealing agent, the sealing effect such as excellent insulating properties is exhibited, and the sealing effect is obtained even if the surface layer is removed by grinding, for example, about 200 μm. Can be confirmed.

By using a sealing agent to be described later, the pores (gap) of the thermal spray coating are substantially completely filled with a resin obtained by polymerizing epoxy groups, so that the thermal spray coating coating member having a continuous coating surface without gaps Can be obtained.
Here, the pores (gap) of the sprayed coating are “substantially all filled” means that the layer formed by the sealing agent existing in the form of a coating on the surface of the sprayed coating (sealing agent) In the dye penetration test based on JIS H 8666, the outermost layer portion (for example, about 0.2 mm thick from the surface) of the thermal spray coating including the cured product of the components contained in the material is removed by grinding and polishing. , Meaning no coloration.

The sealing treatment is preferably performed quickly on the sprayed coating after spraying. The thermal spray coating is a coating formed by fusing a large number of particles having a particle size distribution only at the interparticle surface layer. Since gaps are inevitably generated at the particle boundaries, it is often affected by environmental conditions such as moisture and foreign matter entering through the gaps at the grain boundaries immediately after the formation of the coating. Therefore, in order to prevent a decrease in the sealing efficiency, it is desirable to perform the sealing treatment of the sprayed coating as soon as possible after spraying.
As the sealing treatment method, known methods such as application of a sealing treatment agent to the spray coating and immersion of the spray coating in the sealing treatment agent can be used. Thereafter, a ceramic sprayed coating that has been sealed can be obtained by curing under predetermined curing conditions.

  In the sealing treatment method, the sealing agent penetrates to the bottom of the thermal spray coating and the filling property is improved, so that the gap at the boundary between the particles is reliably filled, so that the bonding force between the particles and the base material can be reduced. The adhesion force is increased, and all gaps between the boundaries between particles can be filled. For this reason, the penetration | invasion of environmental moisture and a foreign material in air | atmosphere is interrupted | blocked, and the fall of an insulation resistance value and a dielectric breakdown value can be suppressed, without reducing the intrinsic | native value of an oxide ceramic sprayed coating. Further, the obtained thermally sprayed coating after sealing does not have an exposed gap even when the surface is ground or polished. Therefore, the obtained thermal spray coating member can be used in a railway vehicle motor with a thermal spray coating that has improved mechanical strength and adhesion strength to the base material, and further improves electrical characteristics such as insulation resistance value and dielectric breakdown value. Since the outer peripheral surface of the outer ring of the rolling bearing is formed, the housing and the bearing are insulated and the occurrence of electrolytic corrosion can be prevented.

  When sealing treatment is performed using a sealing treatment agent described later, the coating with the sealing treatment agent is formed so as to conceal the surface layer of the thermal spray coating after the gap between the thermal spray coatings is substantially filled with the sealing treatment agent. A thin layer is formed. The coated member having a thin layer in the form of a coating can be used as it is, but in order to maintain the dimensional accuracy of the coated member, the surface of the sprayed coating is ground and ground using a grinding wheel, abrasive paper, non-woven buff, etc. This layer can be removed by polishing.

The electric corrosion-preventing rolling bearing for motors of the present invention forms a ceramic sprayed coating on the surface of a bearing component, contains an epoxy group-containing component and a curing agent, and is sealed with a sealing agent that does not contain a polymerizable vinyl group-containing solvent. Apply hole treatment.
The epoxy group-containing component is a polyglycidyl ether compound having 3 or more epoxy groups contained in one molecule as an essential component, and an alkylene diglycidyl ether compound having 2 epoxy groups contained in one molecule. And a mixture containing at least one selected from cycloaliphatic diepoxy compounds, and the epoxy group-containing component has a polyglycidyl ether compound content of 10 to 10 with respect to the entire epoxy group-containing component excluding the curing agent. 80% by weight. The epoxy group-containing component may further contain a monoglycidyl ether compound having one epoxy group in one molecule.

The sealing agent used in the present invention is a thermal spray coating sealing agent containing an epoxy group-containing component and a curing agent, and not containing a polymerizable vinyl group-containing solvent, wherein the epoxy group-containing component is a predetermined component. Since the mixture is mainly composed of a polyglycidyl ether compound, it effectively suppresses the generation of voids due to the volatilization of the solvent in the sealing agent, and seals until the gap between the sprayed coating materials is substantially filled. Hole treatment can be applied.
A mixture of a plurality of polyglycidyl ether compounds is excellent in compatibility since the molecular structure is similar, and therefore can easily penetrate into the pores since there is no possibility of phase separation or the like. For this reason, it is possible to avoid the possibility of deterioration of the sealing state of the thermal spray coating material and sealing characteristics over time, and prevent damage such as peeling of the thermal spray coating or cracking during use, and coating of the energized substance entering from the damaged site Prevent intrusion. And by preventing the occurrence of a potential difference between the inner and outer rings of the bearing, it is possible to prevent the occurrence of electrolytic corrosion on the raceway surface and the rolling element surface, and consequently improve the life of the bearing of the motor for the railway vehicle. it can.

In addition, since the sealing agent used in the present invention is excellent in the permeability and filling property to the pores (gap) of the sprayed coating, the sealing layer is sealed even when the surface layer portion of the sprayed coating is ground or polished after the sealing treatment. There is a sufficient penetration / filling layer of the treatment agent, and as a result, the substrate protection of the coating can be greatly improved even after polishing, and the physical properties such as mechanical properties and electrical properties can be kept high. it can.
This is because the sealing agent that has penetrated the particle boundary due to its excellent permeability and filling property properly fills the particle boundary, firmly adheres to the particle boundary due to excellent adhesive force, and contains a solvent containing a polymerizable vinyl group Therefore, it is considered that the sealing treatment could be performed to a state where substantially all the gaps of the thermal spray coating material were filled by effectively suppressing the generation of voids due to the volatilization of the solvent. The present invention has been completed based on such findings.

  The sealing agent used in the present invention comprises a polyglycidyl ether compound having 3 or more epoxy groups contained in one molecule as an essential component, and in addition to this essential component, an epoxy group contained in one molecule. It is a mixture containing an alkylene diglycidyl ether compound having two numbers and / or a cycloaliphatic diepoxy compound having two epoxy groups contained in one molecule. A polyglycidyl ether compound and a cycloaliphatic diepoxy compound are compounds that do not contain a repeating unit formed by cleavage of an oxirane ring in the molecule. The mixture of the present invention reacts with a curing agent to form a cured product.

Examples of the polyglycidyl ether compound having 3 or more epoxy groups contained in one molecule include triglycidyl ether compounds and tetraglycidyl ether compounds. Examples of the polyglycidyl ether compound include trimethylolpropane polyglycidyl ether, glycerol triglycidyl ether, and sorbitol polyglycidyl ether.
Among these, from the viewpoint of lowering the viscosity of the sealing agent, a triglycidyl ether compound is preferable, and trimethylolpropane polyglycidyl ether is particularly preferable.

  Examples of the alkylene diglycidyl ether compound having two epoxy groups contained in one molecule include neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,6- Mention may be made of hexanediol diglycidyl ether.

  The cycloaliphatic diepoxy compound having two epoxy groups contained in one molecule is a so-called alicyclic compound in which two adjacent carbon atoms form an oxirane ring. Examples of the alicyclic epoxy compound include alicyclic diepoxy compounds containing two oxirane rings, such as 1,2,8,9-diepoxy limonene. It is a preferred compound that effectively prevents the physical properties of the treated product from being lowered while lowering the viscosity of the sealing agent. Further, diglycidyl ethers of alicyclic compounds such as hydrogenated bisphenol A and diglycidyl ether of tetrahydrophthalic acid can also be used.

  The sealing agent that can be used in the present invention is a monoglycidyl ether compound having one epoxy group in one molecule for the purpose of improving the handleability and further improving the permeability to the spray coating material. Can be blended. Examples of the monoglycidyl ether compound having one epoxy group contained in one molecule include known monoglycidyl ether compounds such as alkyl monoglycidyl ethers such as butyl glycidyl ether and alkylphenol monoglycidyl ethers.

  The triglycidyl ether compound can be used as a sealing agent component that dramatically increases the adhesion between the thermal spray coating and the metal substrate. At the same time, since the viscosity of the compound itself is low, it is not necessary to add an organic solvent such as xylene and methyl ethyl ketone, or a polymerizable vinyl group-containing solvent by mixing with a diglycidyl ether compound described later, and a sealing agent. In contrast, sufficient permeability can be imparted.

In addition, when the amount of chlorine ions contained in the resin is 0.5% by weight or less, it is possible to suppress deterioration of electrical characteristics such as insulation resistance in a humid atmosphere and corrosivity of the base material.
The viscosity of the triglycidyl ether compound at 25 ° C. is preferably 500 mPa · s or less. If it exceeds 500 mPa · s, the permeability is poor.

  The blending ratio of the triglycidyl ether compound is preferably 10 to 80% by weight, more preferably 20 to 50% by weight, based on the entire mixture as the sealing agent. If it is less than 10% by weight, the viscosity of the sealing liquid itself can be set low. The adhesive strength of is reduced. Further, when the blending ratio of the triglycidyl ether compound exceeds 80% by weight, the viscosity of the sealing agent is increased, so that the permeability is poor.

  Since the alkylene diglycidyl ether compound having two epoxy groups contained in one molecule is an epoxy compound having a low viscosity in itself, the viscosity of the sealant may be reduced by addition to the polyglycidyl ether. This is preferable because it is possible. Addition of a cycloaliphatic diepoxy compound as shown in 1,2,8,9-diepoxy limonene is also preferred. Since these compounds are integrated by copolymerizing with epoxy molecules at the time of the curing reaction, it is preferable because the physical properties of the cured product can be prevented from being reduced by blending and the volume at the time of curing can be prevented.

  The viscosity of the alkylene diglycidyl ether compound at 25 ° C. is preferably 30 mPa · s or less. If it exceeds 30 mPa · s, the viscosity of the sealant will increase, resulting in poor permeability. The blending proportion of the alkylene diglycidyl ether compound is preferably 10 to 80% by weight, more preferably 50 to 80% by weight, based on the entire mixture. When it is less than 10% by weight, the effect of reducing the viscosity of the sealant is reduced, and the permeability of the sealant cannot be increased. If the amount exceeds 80% by weight, the permeability of the sealant increases, but the blending ratio of the triglycidyl ether compound, which has a role of forming a high-density cross-linked structure at the time of curing, relatively decreases. The physical properties of the cured epoxy resin are lowered.

  The alkylene diglycidyl ether compound is mixed with the above-mentioned triglycidyl ether compound in a predetermined amount so that the substrate adhesion force, molecular cross-linking density, and resin hardness of the triglycidyl ether compound itself are not significantly reduced. By ensuring the penetration of the treatment agent, a sufficient function as a sealing treatment agent for thermal spray coating can be exhibited.

  A monoglycidyl ether compound having one epoxy group contained in one molecule can be bonded to a part of the resin through a monofunctional group. In addition, since it is a low-viscosity epoxy compound itself, the viscosity of the sealing agent can be lowered, and on the other hand, it can reduce the residual stress inside the cured resin and provide an effect of adjusting the curing rate. it can. It is preferable that the compounding quantity of a monoglycidyl ether compound shall be 0-50 weight% with respect to the whole mixture. When the added amount of monoglycidyl ether compound exceeds 50% by weight, the amount of volatilization increases, the amount of triglycidyl ether compound decreases relatively, the crosslinking density of the resin after curing is insufficient, and the physical properties are greatly reduced. It becomes difficult to form a cured product. Moreover, since the compounding quantity of a polyglycidyl ether compound also reduces, the adhesive force between a thermal spray coating and a base material becomes small.

  A curing agent is blended with the mixture of the glycidyl ether compounds. As the curing agent, a known epoxy resin curing agent such as an acid anhydride and an aliphatic amine compound, an alicyclic amine compound, an aromatic amine compound, or an imidazole may be used alone or in combination. Can do.

  Examples of the acid anhydrides include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenone tetracarboxylic anhydride, ethylene glycol bistrimellitate, glycerol trislimitate, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydro Phthalic anhydride, endomethylenetetrahydrophthalic anhydride, methylendomethylenetetrahydrophthalic anhydride, methylbutenyltetrahydrophthalic anhydride, succinic anhydride, dodecenyl succinic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylcyclohexene Examples thereof include dicarboxylic acid anhydrides and derivatives thereof.

  Examples of amine compounds include chain aliphatic polyamines such as diethylenetriamine and triethylenetetramine, cyclic aliphatic polyamines such as N-aminoethylpiperazine and isophoronediamine, aliphatic aromatic amines such as xylylenediamine, metaphenylenediamine, and diaminodiphenylamine. And aromatic amines and derivatives thereof.

  Of these, acid anhydride curing agents with a viscosity at 25 ° C of 50 mPa · s or less, and aliphatic amine curing agents with a viscosity at 25 ° C of 10 mPa · s or less, Since the viscosity can be remarkably lowered, it becomes a suitable curing agent. In particular, an acid anhydride curing agent that can prolong the pot life of the sealing agent, has a low shrinkage during curing, and is excellent in electrical characteristics is preferable. It is preferable that the compounding quantity of an acid anhydride hardening | curing agent shall be 0.80-0.95 equivalent with respect to 1 equivalent of epoxy groups.

  A surfactant can be added as an additional material to the sealing agent that can be used in the present invention. Particularly effective surfactants include fluorine-based surfactants and silicon-based surfactants, and it is particularly preferable to use known fluorine-based surfactants. In the present invention, known anionic, cationic, nonionic and amphoteric surfactants can be used. When a fluorine-based surfactant is added to the sealing agent of the present invention, it can be used alone or in admixture of two or more. Moreover, if it is an additive which improves the surface active effect and the osmosis | permeation effect, such as silicone oil, it can be used in the range which does not disturb the characteristic of invention.

  As the anionic surfactant, sulfonate, sulfate, carboxylate, phosphate, phosphonate, phosphate ester and the like can be used. As the cationic surfactant, a quaternary ammonium salt, an amino halogen salt, or the like can be used. As the nonionic surfactant, polyoxyethylene ester type, polyoxyethylene ether type, sorbitan ester type and the like can be used. As the amphoteric surfactant, imidazoline type, betaine type and the like can be used.

Examples 1 to 5 and Comparative Examples 1 to 7
The materials used in Table 1 are shown below.
(1) Glycidyl ether compound or cycloaliphatic diepoxy compound (1-1) Trimethylolpropane triglycidyl ether: manufactured by Nagase ChemteX Corporation, Denacol EX-321L, viscosity: 500 mPa · s (25 ° C.)
(1-2) Phenylenediglycidyl ether: manufactured by Nagase ChemteX Corporation, Denacol EX-201, viscosity; 240 mPa · s (25 ° C.)
(1-3) alkylene diglycidyl ether: manufactured by Japan Epoxy Resin Co., Ltd., YED216M, viscosity; 15 mPa · s (25 ° C.)
(1-4) Alkylene monoglycidyl ether: manufactured by Japan Epoxy Resin, YED111E, viscosity; 7 mPa · s (25 ° C.)
(1-5) Cycloaliphatic diepoxy compound: Daicel Chemical Industries, Celoxide 3000, viscosity; 10 mPa · s (25 ° C.)
(2) Epoxy resin (2-1) Bisphenol F type epoxy resin: manufactured by Japan Epoxy Resin, Epicoat 806, viscosity; 2000 mPa · s (25 ° C.)
(3) Curing agent, curing accelerator (3-1) Acid anhydride curing agent: manufactured by Dainippon Ink & Chemicals, Epicron B-570, viscosity; 40 mPa · s (25 ° C.)
(3-2) Imidazole-based curing accelerator: Shikoku Kasei Kogyo Co., Ltd., OR-2E4MZ
(4) Polymerizable vinyl group-containing solvent (4-1) Styrene monomer: Wako Pure Chemical Industries, reagent

Each component shown in Table 1 was sufficiently stirred and mixed at room temperature, and left to stand for 30 minutes to remove bubbles in the mixed resin, thereby obtaining a sealing agent. The obtained sealing agent was evaluated by a weight reduction rate test after firing.
<Weight reduction test after firing>
The obtained sealing agent was sufficiently dried at 140 ° C. for 2 hours, and weighed about 2 g in a glass container with no foreign matter adhered (capacity: 3 ml) to obtain a weighed value before firing. Then, with the mouth of the glass container kept open, pre-fired at 80 ° C for 1 hour, then fired at 120 ° C for 2 hours, measured the weight after firing, set the weight after firing, and sealed according to the following formula The weight reduction rate of the treatment agent was measured. The measurement results are shown in Table 1. The criterion for the measurement results is that if the weight loss rate exceeds 1%, voids will form after curing in the microscopic voids remaining in the sprayed coating, or the generation of residual bubbles in the cured product will increase due to the generated gas. Therefore, it is judged as “impossible” and 1% or less can be judged as “possible”. Further, “uncured” is a case where the material did not become solid under the above-described firing conditions.

Weight reduction rate after firing (%) = 100 × (weighed value before firing−weighed value after firing) / weighed value before firing

Next, a φ20 mm × 25 mm SUJ2 test piece (hereinafter referred to as “test piece base material”) was prepared, and an alumina ceramic sprayed coating having a film thickness of 400 μm was formed on the cylindrical end face by an atmospheric plasma spraying method.
On the surface of the sprayed surface, the sealing agent shown in Table 1 was applied using a polyamide brush in a room temperature atmosphere and allowed to stand for 30 minutes. Thereafter, a test piece coated with a sealing agent was prepared by scraping off the excess sealing agent on the surface with a polyethylene spatula. Thereafter, these coated test pieces were pre-fired at 80 ° C. for 1 hour, and then fired at 120 ° C. for 2 hours to cure the sealing agent. Next, grinding removal was performed using a diamond grindstone parallel to the ceramic plane. The grinding removal amount was set to the following two levels.
(1) The ceramic part was ground and removed by about 10 μm for the purpose of intensively removing the cured resin layer on the surface layer part.
(2) About 200 μm was ground and removed for the purpose of removing the resin permeation layer from the surface of the cured specimen to a depth of about 200 μm.
Measure the permeability, adhesion, insulation resistance, and withstand voltage characteristics with the following permeability test, adhesion test, insulation resistance test, and withstand voltage test using the cured specimen obtained by grinding and removing the surface. did.

<Penetration test>
The permeability test of the cured test piece was performed by applying a ferroxyl test based on JIS H 8666 to the coating surface 9 of the cured test piece base material 8 subjected to the sealing treatment. An outline of the ferroxyl test is shown in FIG. The test conditions were the test solution composition, test surface, except that the shape of the filter paper 10, the tin plate 11, and the weight 12 immersed in the test solution shown in FIG. 3 was adjusted to the test piece (φ16 mm). All conditions such as pressure and standing time were in accordance with JIS H 8666. When the filter paper 10 is colored, the sprayed coating 9 has a communication hole for connecting the test piece base 8 and the external space, so that the ferroxyl test solution comes into contact with the iron ions of the test piece base 8 and becomes blue. Indicates that Judgment criteria are “spotted” if one or more blue spots were seen on the surface of filter paper 10 that was originally white, and “no spots” if zero blue spots were found, The permeability measurement results are also shown in Table 1.

<Adhesion test>
An outline of the adhesion test is shown in FIG. A tensile jig 13 (adhesive shape: φ16 mm) is bonded to the cured test piece base material 8 with the surface layer portion after firing removed by grinding by 200 μm via an epoxy adhesive surface 9a through a high-viscosity epoxy adhesive. The adhesion of the thermal spray coating 9 per unit area was measured by pulling in the direction of the arrow with a tensile and compression tester. The measurement results are also shown in Table 1. Judgment criteria are “possible” when the adhesion is 2 MPa or more, and “impossible” when it is below 2 MPa.

<Insulation resistance test>
An outline of the insulation resistance test is shown in FIG. After immersing the cured specimen base material 8 in 80 ° C. warm water for 1 hour, the insulation resistance between the surface of the sprayed coating 9 and the specimen base material 8 was measured using a 1000 V DC insulation resistance meter 15 attached to the wiring 16. . Reference numeral 14 denotes an electrode. The measurement results are also shown in Table 1. The criterion is “Yes” when the resistivity is 2000 MΩ or more (indicated as> 2000 in the table), and “No” when the resistivity is lower than 2000 MΩ.

<Withstand voltage characteristics test>
An outline of the withstand voltage characteristic test is shown in FIG. A voltage of DC 5 kV was applied by a high voltage generator 17 attached to the wiring 16 between the thermal spray coating 9 and the test piece substrate 8, and the withstand voltage characteristics were evaluated by the monitor 18. Reference numeral 14 denotes an electrode. The measurement results are also shown in Table 1. The judgment criteria were DC 5 kV applied for 5 minutes, "No" if no dielectric breakdown occurred, and "No" if dielectric breakdown occurred.

Next, a deep groove ball bearing 6204 (hereinafter referred to as “bearing test piece 19”) that can be used as an electric corrosion prevention rolling bearing for a motor was manufactured.
Details of the manufacturing method are shown below.
(1) A 6204 bearing outer ring test piece is prepared, and foreign substances such as rust preventive oil are sufficiently removed using petroleum benzine.
(2) A disc-shaped masking jig is attached so that shot blast powder does not enter the inner peripheral surface of the outer ring, and a bearing test piece is attached to the rotating device.
(3) While rotating the bearing test piece at 10 rpm, an alumina ceramic sprayed coating was formed on the outer peripheral surface of the cylinder and both end faces by an atmospheric plasma spraying method so that the film thickness was 400 μm. At this time, cooling was performed by blowing dry air from the inside of the bearing.
(4) Edge the masking jig and the workpiece with a diamond grindstone to separate the masking jig.
(5) Each sealing agent shown in Table 1 was applied to the surface of the sprayed surface of the bearing test piece in a room temperature atmosphere using a polyamide brush and allowed to stand for 30 minutes. Then, the excess sealing agent on the surface is scraped off with a polyethylene spatula. Thereafter, these test pieces were pre-fired at 80 ° C. for 1 hour and then fired at 120 ° C. for 2 hours to cure the sealing agent.
(6) The outer shape and the width surface of the bearing test piece were ground and removed using a diamond grindstone. The removal amount of the sprayed surface by grinding was about 200 μm.
Using the test piece obtained by grinding and removing the outer diameter and the width surface of the bearing test piece, the following insulation resistance test and withstand voltage characteristic test were performed.

<Insulation resistance test using bearing specimen>
An outline of the insulation resistance test using a bearing test piece is shown in FIG. The bearing test piece 19 is immersed in warm water of 80 ° C for 1 hour, wiped with a dry cloth, allowed to cool to room temperature, and then press-fitted into the housing 5a with a tightening margin of 20 µm, and the width surface fixing lid 20 is fixed with bolts. To do. Using a 1000 V DC insulation resistance meter 15 attached to the wiring 16, the insulation resistance between the bearing test piece 19 and the housing 5a was measured. The measurement results are also shown in Table 1. Judgment criteria are determined as “Yes” when the resistivity is 2000 MΩ or more (indicated as> 2000 in the table), and “Not possible” when the resistivity is lower than 2000 MΩ.

<Withstand voltage characteristics test using bearing specimen>
Since the basic configuration of the withstand voltage characteristic test is the same as the insulation resistance test using the bearing test piece, the illustration is omitted. A bearing test piece 19 was attached to the housing 5a, a voltage of DC 3 kV was applied by a high voltage generator 17 attached between both members, and the withstand voltage characteristics were evaluated by a monitor. The measurement results are also shown in Table 1. The criterion was DC 3 kV applied for 1 minute, “No” if no dielectric breakdown occurred, and “No” if dielectric breakdown occurred.

  As shown in Table 1, the sealing agent of each example has a weight reduction rate of less than 1%. Since Comparative Examples 2, 6, and 7 have relatively large amounts of bifunctional epoxy components and monofunctional epoxy components that are relatively volatile, the permeability is not a problem, but it is considered that defects occurred in the cured compound and the physical properties decreased. In particular, Comparative Examples 2 and 6 had a role of forming a high-density cross-linking point in the cured product, and therefore the content of the trifunctional epoxy component was small. It is considered that the volatilization of the functional epoxy component has progressed. Further, Comparative Example 1 did not form a cured product under the main curing conditions.

  When the grinding removal amount is 200 μm, the adhesion of the test pieces subjected to the sealing treatment of each example is higher than that of all the comparative examples except comparative examples 5 and 7. The composition of the sealing agent of the present invention not only fills the pores (gap) of the sprayed coating, but also penetrates to the test piece base material interface, and the inherent adhesion of the sealing agent is also effective. It is thought that it demonstrated.

When the grinding removal amount was 200 μm, the insulation resistance value of each example was 2000 MΩ or more, and Comparative Examples 3, 4 and 5 were 1 MΩ or less. In each example, it is considered that the decrease in the original insulation resistance value of alumina is suppressed by preventing the conduction phenomenon considered to be due to the intrusion of moisture into the film by the sealing treatment. Although the comparative example 5 was able to form hardened | cured material, since the used bifunctional epoxy compound was a high-viscosity aromatic epoxy compound, it thinks that the penetration | permeation to a base-material interface part was not aimed at. In Comparative Examples 2 and 6, the viscosity was sufficiently low so that the permeability was secured and the intrusion of moisture into the coating could be prevented. However, since the amount of trifunctional glycidyl ether groups was small, sufficient adhesion was achieved. I couldn't get power.
In addition, although all the test pieces of each example were stably maintained for 10 minutes, all the test pieces of the comparative examples were subjected to spark discharge immediately after voltage application, resulting in dielectric breakdown.

  The electric corrosion prevention rolling bearing for a motor of the present invention uses a predetermined sealing treatment agent as a sealing treatment agent for sealing a ceramic sprayed coating, and therefore causes electric corrosion over a long period of time. It can suppress transmission and has a high effect of preventing electric corrosion for a long time. As a result, it can be suitably used for a bearing of a railway vehicle motor or the like.

It is a fragmentary sectional view of the electric corrosion prevention cylindrical roller bearing for motors. It is sectional drawing of the electric corrosion prevention deep groove ball bearing for motors. It is a figure which shows the outline of a ferroxyl test. It is a figure which shows the outline of an adhesive force test. It is a figure which shows the outline of an insulation resistance test. It is a figure which shows the outline of a withstand voltage characteristic test. It is a figure which shows the outline of the insulation resistance test by a bearing test piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 2 Outer ring 3 Cage 4 Rolling body 5 Housing 6 Shaft 7 Sealed ceramic sprayed coating 8 Test piece base material 9 Sealed sprayed coating 10 Filter paper with ferroxyl test solution 11 Tin plate 12 Weight 13 Tensile jig 14 Electrode 15 Insulation resistance meter 16 Wiring 17 High voltage generator 18 Monitor 19 Bearing test piece 20 Width surface fixed lid

Claims (3)

An electric corrosion-preventing rolling bearing for a motor having a ceramic sprayed coating sealed in a portion capable of preventing the occurrence of electric corrosion generated on the raceway surface and rolling element surface of a rolling bearing used in a motor for a railway vehicle. ,
The sealing agent for performing the sealing treatment includes an epoxy group-containing component and a curing agent, does not include a polymerizable vinyl group-containing solvent, and the epoxy group-containing component is an epoxy group contained in one molecule. A mixture containing, as an essential component, a polyglycidyl ether compound having a number of 3 or more, and containing at least one selected from an alkylene diglycidyl ether compound and a cycloaliphatic diepoxy compound having two epoxy groups in one molecule An electroerosion-preventing rolling bearing for motors, characterized in that it is a sealing agent in which 10 to 80% by weight of a polyglycidyl ether compound is blended with respect to the entire epoxy group-containing component excluding the curing agent. .   2. The electric corrosion-preventing rolling bearing for motor according to claim 1, wherein the portion capable of preventing the occurrence of electrolytic corrosion is a surface on which the rolling bearing and at least a housing or a shaft are fitted.   2. The electric corrosion-preventing rolling bearing for motor according to claim 1, wherein the epoxy group-containing component further comprises a monoglycidyl ether compound having one epoxy group contained in one molecule.

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