JP2008298117A - Rolling bearing for ct scanner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing for a CT scanner capable of preventing or restraining noises without leakage of lubricant. <P>SOLUTION: This rolling bearing 1 for a CT scanner comprises an inner ring 2, an outer ring 3, and a plurality of rolling elements 4 incorporated between raceways of the inner and outer rings 2, 3. Foamed solid lubricant 8 is filled in a bearing space surrounded by the inner and outer rings 2, 3 and the rolling elements 4, and the rolling bearing rotatably supports a rotary pedestal rotating around an object. The foamed solid lubricant 8 is formed by foaming and solidifying mixture containing a lubricating component, a resin component, a hardening agent, and a foaming agent. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a rolling bearing for a CT scanner used for medical equipment and the like.
About.

  An example of a CT scanner device which is a kind of medical equipment is shown in FIG. In the CT scanner device, the subject 24 is irradiated with X-rays generated by the X-ray tube device 21 through a wedge filter 22 that makes the intensity distribution uniform and a slit 23 that restricts the intensity distribution. X-rays that have passed through the subject 24 are received by the detector 25, converted into electrical signals, and sent to a computer (not shown). Each component such as the X-ray tube device 21, the wedge filter 22, the slit 23, and the detector 25 is mounted on a substantially cylindrical rotary mount 27 that is rotatably supported by the fixed mount 26 via the bearing 11. As the gantry 27 rotates, the periphery of the subject 24 rotates. In this way, by rotating the X-ray tube device 21 and the detector 25 facing each other around the subject 24, projection data covering all angles of all points in the inspection section of the subject 24 is obtained, and these data are acquired. A tomographic image is obtained from a reconstruction program programmed in advance.

  In the CT scanner device, the inner peripheral surface of the fixed gantry 26 is formed to have a large diameter of about 1 m in diameter so that the subject 24 can enter, so the bearing 11 between the fixed gantry 26 and the rotary gantry 27 includes An extremely thin-walled CT scanner rolling bearing having a remarkably small cross section with respect to the diameter is used.

  An example of the cross-sectional structure of the ultra-thin type rolling bearing 11 used in the CT scanner device is shown in FIG. This bearing 11 includes a ring-shaped outer ring 13, a ring-shaped inner ring 12 concentrically arranged on the inner peripheral side of the outer ring 13, and a rolling element (ball) interposed between the outer ring 13 and the inner ring 12 so as to be freely rollable. ) 14, a retainer 15 for holding the balls 14 at equal intervals in the circumferential direction, and seal members 16 a and 16 b for sealing both end openings of the bearing. The seal members 16a and 16b have a labyrinth structure without providing a seal lip in contact with the inner ring 12 in order to prevent an increase in torque due to sliding with the inner ring 12. For this reason, grease in the bearing may leak and contaminate the surrounding environment. The environment used is a medical site in a hospital, and contamination of subjects and peripheral devices due to grease leakage is accompanied by human discomfort and has a serious adverse effect on the image of a medical site that should be clean.

  In addition, resin bearings are often used as ultra-thin type rolling bearings for CT scanner devices because low noise and low torque are desired. For example, as shown in FIG. 4, this resin-made cage is formed by connecting a plurality of arc-shaped segments in an annular shape, and adjacent segments are unevenly fitted at the end portions. Therefore, a heat-solidifying lubricant that does not leak grease (for example, polylube manufactured by NTN) cannot be fired and cannot be used.

  In addition, depending on the internal clearance of the bearing and usage conditions, the rolling element may be advanced or delayed, resulting in unstable cage behavior, rubbing noise caused by the cage coming into contact with the raceway, and non-joint segments. A hitting sound or the like hits the ring. Such a rubbing noise is also a problem in a bearing used for a CT scanner or the like that requires high speed and quietness.

As a method for preventing the generation of abnormal noise around the cage, a method using a predetermined resin material or a cage having a predetermined structure is known (see Patent Documents 1 to 3). In order to improve the detection accuracy and detection speed, the device is required to increase the rotational speed of the bearing from about 60 rpm to 200 to 300 rpm, and these methods are not effective enough. I can't say that.
JP 2004-19921 A JP 2006-266458 A JP 2006-300193 A

  The present invention has been made to address such problems, and an object of the present invention is to provide a rolling bearing for a CT scanner that is free from lubricant leakage and can prevent or suppress the generation of abnormal noise.

A rolling bearing for a CT scanner according to the present invention includes an inner ring, an outer ring, and a plurality of rolling elements incorporated between races of the inner and outer rings, and foams in a bearing space surrounded by the inner and outer rings and the rolling elements. A rolling bearing for a CT scanner that encloses a solid lubricant and rotatably supports a rotating base that rotates around a subject. The foamed solid lubricant includes a lubricating component, a resin component, and a curing agent. And a foamed solid lubricant obtained by foaming and curing a mixture containing a foaming agent.
The foamed solid lubricant is sealed between at least an outer diameter surface of a cage that holds the rolling elements and an inner diameter surface of the outer ring.

Among the above-mentioned foamed solid lubricants, the first foamed solid lubricant is at least one lubricating component whose lubricating component is selected from hydrocarbon-based lubricants and hydrocarbon-based greases, and the resin component is a polymer main component. The rubber is a liquid rubber having a hydroxyl group in an amount such that the chain is composed of hydrocarbon and the hydroxyl value of the main chain end is 25 mg KOH / g to 110 mg KOH / g, and the curing agent has an isocyanate group in the molecule. It is an organic compound, the foaming agent is water, and the ratio of the liquid rubber to the curing agent is such that the hydroxyl group contained in the liquid rubber and the isocyanate group contained in the curing agent are equivalent (OH / NCO ) = 1 / (1.0 to 2.0), and the mixture contains 40% to 80% by weight of the lubricating component and 5% to 45% by weight of the liquid rubber with respect to the whole mixture. Features.
Further, the liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3500 having a hydroxyl group at the main chain terminal of a butadiene or isoprene polymer, or a modified hydroxyl group-terminated diene system obtained by hydrogenating the diene polymer. It is a polymer.
The organic compound having an isocyanate group in the molecule is a prepolymer having two or more isocyanate groups in the molecule and a ratio of the isocyanate group of 2.5 NCO% to 5.0 NCO%, or aromatic. It is a polyisocyanate.

Among the foamed solid lubricants, the second foamed solid lubricant is at least one lubricating component in which the lubricating component is selected from lubricating oil and grease, and the resin component has an isocyanate group content of 2% by weight. More than 6% by weight of urethane prepolymer, the foaming agent is water, and the mixture contains 30% to 70% by weight of the lubricating component with respect to the whole mixture, and the open cell ratio after foaming is It is characterized by being 50% or more. The urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer.
Further, the ratio of the isocyanate group to the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). And
The ratio of the hydroxyl group of water to the functional group of the curing agent is an equivalent ratio (hydroxyl group of water / functional group of the curing agent) = 1 / (0.7 to 2.0).
The curing agent is an aromatic polyamino compound, particularly an aromatic polyamino compound having a substituent at a position adjacent to an amino group.

  The rolling bearing for CT scanner of the present invention is formed by enclosing a foamed solid lubricant in a bearing space surrounded by inner and outer rings and rolling elements, and the foamed solid lubricant has a lubricating component and a resin component as essential components, The resin component is a solid material which is made porous by curing and foaming, and the lubricating component is occluded in the foamed and cured solid component. For this reason, the foamed solid lubricant encapsulated in the rolling bearing for the CT scanner of the present invention can release the lubricating component from the resin molecules to the outside, so that the lubricating component that oozes as the bearing rotates is used for bearing lubrication. The required minimum amount can be achieved, and there is no leakage outside the bearing. In the present invention, “occlusion” means that a liquid / semi-solid lubricating component does not react with other compounding components and is contained in a solid resin without becoming a compound.

  In addition, the encapsulated foamed solid lubricant fills the entire bearing space surrounded by the inner and outer rings and rolling elements, including the cage, so it absorbs sound and propagates sound outside the bearing. Can be cut off, and the quietness of the bearing can be maintained.

Further, by encapsulating the foamed solid lubricant, the lubricant can be present near the rolling surface, and the lubricant is more easily supplied to the rolling surface than grease lubrication. In addition, since it has many porous portions, it is advantageous in terms of reducing the weight of the bearing.
In addition, since it is not necessary to enclose a lubricant after assembly, production efficiency is improved and manufacturing can be performed at low cost.

The rolling bearing for CT scanner of this invention is demonstrated based on drawing. FIG. 1 is a sectional view showing an embodiment of a rolling bearing for a CT scanner according to the present invention.
As shown in FIG. 1, a rolling bearing 1 for a CT scanner includes an inner ring 2, an outer ring 3, a plurality of rolling elements 4 incorporated between the raceways of the inner and outer rings 2 and 3, and a holding for holding the rolling elements 4. And a non-contact seal member 6a, 6b, and a foaming solid in a bearing space surrounded by the inner / outer rings 2, 3, the rolling element 4, the cage 5, and the seal members 6a, 6b. A lubricant 8 is enclosed. A four-point contact ball bearing having a contact angle α between the rolling element 4 and the inner ring 2 and the outer ring 3 in order to cope with a moment load acting on a bearing that rotates while supporting a base on which a device such as a detector is mounted. Is used. The outer ring 3 is attached to a fixed member by a bolt 7a through a spacer 9, and the inner ring 2 is attached to a rotating member by a bolt 7b.

  The foamed solid lubricant encapsulated in the rolling bearing for the CT scanner of the present invention occludes the lubricating component in the resin, so that it is lubricated by the flexibility of the resin, for example, deformation due to external force such as compression, expansion, bending, torsion or capillary action. The agent can be exuded and released gradually from between the resin molecules. At this time, the amount of lubricating oil that oozes out can be used for lubrication with the minimum necessary amount by changing the degree of elastic deformation according to the magnitude of the external force, depending on the choice of resin, etc. I do not put out.

  Since the foamed solid lubricant 8 enclosed in the rolling bearing for the CT scanner fills the entire bearing space surrounded by the inner and outer rings and the rolling elements 4, the cage 5 for holding the rolling elements 4 is also foamed. It is embedded and fixed in the solid lubricant 8 and can suppress the generation of sliding noise and friction noise accompanying rotation. In addition, by absorbing the generated sliding sound and frictional sound into the bubbles in the foamed solid lubricant, it can also serve as a soundproofing material and a sound deadening material.

Furthermore, this foamed solid lubricant requires very little energy when bent compared to a non-foamed body, and can be flexibly deformed while retaining the lubricating component at a high density. Therefore, in the process of solidifying the foamed solid lubricant and cooling it, even if the foamed solid lubricant contracts and embraces the rolling element, it can be easily deformed because the energy required for bending and deformation is small. The problem of increased rotational torque can be prevented. Moreover, since it has many foamed parts, ie, a porous part, it is advantageous also at the point of weight reduction.
In addition, since the foamed solid lubricant used in the present invention only foams and cures a mixture containing a lubricating component and a resin component as essential components, no special equipment is required, and it is filled and molded in any place. Is possible.
Further, the density of the foamed solid lubricant can be changed by controlling the blending amount of the blending components of the mixture.

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

For the resin component of the foamed solid lubricant used in the present invention, it is preferable to use a urethane resin that is excellent in heat resistance and flexibility and can be reduced in cost. As the resin component, a first foamed solid lubricant using a liquid rubber having a hydroxyl group in the molecule described below and a second foamed solid lubricant using a urethane prepolymer containing a predetermined NCO are preferable.
Moreover, the resin component obtained by making the polyether polyol and polyisocyanate as a polyol react can be used.

As the resin component used in the first foamed solid lubricant that can be used in the present invention, it is preferable to use a urethane resin that is excellent in heat resistance and flexibility and can be reduced in cost. The hydroxyl group-containing component that forms the urethane resin is preferably a liquid rubber having a hydroxyl group in the molecule. This liquid rubber has a polymer main chain composed of hydrocarbons, and a hydroxyl value of 25 to 110 mg KOH at the end of the main chain. A liquid rubber having a hydroxyl group in an amount of / g 2 is preferable. When the hydroxyl value is less than 25 mg KOH / g, foaming / curing is not sufficient, and when the hydroxyl value exceeds 110 mg KOH / g, the elasticity of the foamed solid lubricant may be lost.
This liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3,500 having a hydroxyl group at the main chain terminal of a butadiene or isoprene polymer, or a modified hydroxyl group-terminated diene polymer obtained by hydrogenating the diene polymer. Coalescence can be used.
Examples of the hydroxyl-terminated liquid polybutadiene include poly-bd R45HT (manufactured by Idemitsu Kosan Co., Ltd.), poly-bd R15HT (manufactured by Idemitsu Kosan Co., Ltd.), NISSO-PB G-1000, G-2000, and G-3000 (manufactured by Nippon Soda Co., Ltd.). Examples of the hydroxyl group-terminated liquid polyisoprene include poly-ip (manufactured by Idemitsu Kosan Co., Ltd.), and examples of the hydrogenated hydroxyl group-terminated polydiene compound include Epol (manufactured by Idemitsu Kosan Co., Ltd.), NISSO-PB GI-1000, GI-2000, GI-3000 (made by Nippon Soda Co., Ltd.), etc. are mentioned.

  Further, the hydroxyl group-terminated polydiene compound or the hydroxyl group-terminated polydiene compound obtained by partially modifying the terminal hydroxyl group of the hydroxyl-terminated polydiene compound or the hydrogenated hydroxyl-terminated polydiene compound with an isocyanate group or an epoxy group or the hydrogenated hydroxyl-terminated polydiene compound is also included at the terminal. If it can be used. Two or more of these compounds may be mixed and used for the purpose of controlling the physical properties of the produced foam.

  The hydroxyl group-terminated polydiene polymer or the hydrogenated hydroxyl group-terminated polydiene polymer has a molecular structure similar to that of a lubricating component composed of paraffinic or naphthenic mineral oil composed of hydrocarbons, which will be described later. It is considered that the hydroxyl group-terminated polydiene polymer or the hydrogenated hydroxyl group-terminated polydiene polymer and the lubricating component molecule are intertwined by a relatively weak interaction. Therefore, many lubricating components can be impregnated in the molecule of the hydroxyl-terminated polydiene polymer or the hydrogenated hydroxyl-terminated polydiene polymer, and high lubricating component retention can be exhibited. By applying a strong force such as heat or centrifugal force to this, the interaction between the hydroxyl-terminated polydiene polymer or the hydrogenated hydroxyl-terminated polydiene polymer and the lubricating component is broken, and the lubricating component can be released gradually. it can.

The organic compound having an isocyanate group in the molecule as a curing agent for curing the liquid rubber can be used without particular limitation as long as it is an isocyanate compound that reacts with a hydroxyl group in the liquid rubber to extend the molecular chain or crosslink. Preferred isocyanate compounds include polyisocyanates. Polyisocyanates are particularly preferable because they can react with water to be a foaming agent described later to generate gas.
Examples of the polyisocyanates include polyisocyanates and / or prepolymers having two or more isocyanate groups in the molecule.

Polyisocyanates can include aromatic, aliphatic, or alicyclic polyisocyanates.
Aromatic polyisocyanates include tolylene diisocyanate (hereinafter referred to as TDI), diphenylmethane diisocyanate (hereinafter referred to as MDI), TDI multimer, MDI multimer, naphthalene diisocyanate (NDI), phenylene diisocyanate, diphenylene. Diisocyanate etc. are mentioned.
Examples of the aliphatic polyisocyanates include octadecamethylene diisocyanate, decamethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and xylylene diisocyanate.
Examples of the alicyclic polyisocyanates include isophorone diisocyanate and dicyclohexylmethane diisocyanate.
Further, an adduct of the above polyisocyanate and a polyol such as trimethylolpropane can also be used.
When the reaction with the hydroxyl group that is the terminal functional group of the liquid rubber is performed at a high temperature, a blocked isocyanate in which an isocyanate group is blocked with a blocking agent such as phenols, lactams, alcohols, and oximes can be used. .

  In the case of reacting with a hydroxyl group-terminated polydiene polymer, aromatic polyisocyanates are preferred among the polyisocyanates, and TDI having excellent foamability and reactivity with the hydroxyl group-terminated polydiene polymer is preferred.

As the prepolymer having two or more isocyanate groups in the molecule, any prepolymer having an isocyanate group ratio of 2.5 to 5.0 NCO% can be used. In addition, NCO% is the weight% as an NCO group in a prepolymer. A 2.5 to 5.0 NCO% prepolymer can react with a hydroxyl group-terminated polydiene polymer or the like to obtain a urethane having high elasticity.
Prepolymers are classified into PPG type, PTMG type, ester type, caprolactone type, etc., depending on the type of monomer to be polymerized. There are Takenate L-1170 (manufactured by Mitsui Chemicals Polyurethane) and P-1158 (manufactured by Mitsui Chemicals Polyurethanes) in the PPG system, and Coronate 4090 (manufactured by Nippon Polyurethanes) in the PTMG system. Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), and Sianaprene 7-QM are used as caprolactones. (Mitsui Chemical Polyurethane Co., Ltd.), Plaxel EP1130 (Daicel Chemical Industries Co., Ltd.) and the like.
Two or more kinds of the prepolymers can be mixed and used according to the purpose.

  The blending ratio of the hydroxyl group-terminated polydiene polymer having a terminal hydroxyl group or the hydrogenated hydroxyl group-terminated polydiene polymer and the isocyanate compound having an isocyanate group is equivalent ratio of hydroxyl group (—OH) to isocyanate group (—NCO). The range of (OH / NCO) = 1 / (1.0 to 2.0) is preferable, and the range of (OH / NCO) = 1 / (1.1 to 1.9) is preferable in consideration of particularly excellent foamability and elasticity. When (OH / NCO) is smaller than 1 / 2.0, the isocyanate group becomes excessive, the crosslink density is large, and the elasticity may be poor. On the other hand, when (OH / NCO) is greater than 1 / 1.0, the crosslinking is insufficient and curing is not sufficient.

The lubricating component that can be used for the first foamed solid lubricant can be used as long as it does not dissolve the solid component that forms the foam. Examples of the lubricating component include hydrocarbon-based lubricants, hydrocarbon-based greases, and mixtures of hydrocarbon-based lubricants and hydrocarbon-based greases.
Examples of the hydrocarbon-based lubricating oil include paraffinic and naphthenic mineral oils, hydrocarbon-based synthetic oils, GTL base oils, and the like. These can be used alone or as a mixed oil.
The hydrocarbon-based grease is a grease having a hydrocarbon oil as a base oil, and examples of the base oil include the above-described hydrocarbon-based lubricating oil. Examples of the thickener include lithium soaps, lithium complex soaps, calcium soaps, calcium complex soaps, aluminum soaps, aluminum complex soaps, and other urea compounds such as diurea compounds and polyurea compounds. It is not a thing. The diurea compound is obtained by the reaction of diisocyanate and monoamine, and the polyurea compound is obtained by the reaction of diisocyanate and polyamine.

  As the lubricating component, hydrocarbon synthetic wax, polyethylene wax, higher fatty acid ester wax, higher fatty acid amide wax, ketone / amines, hydrogenated oil, and the like can be mixed and used.

  Since the means for foaming the first foamed solid lubricant uses an isocyanate compound as a raw material, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas.

The first solid foam lubricant is obtained by foaming and curing a mixture containing the above-described lubricating component, liquid rubber, a curing agent, and a foaming agent.
The blending ratio of the lubricating component is 40 to 80% by weight based on the entire mixture. When the lubricating component is less than 40% by weight, the supply amount of lubricating oil and the like is so small that it cannot function as a foamed solid lubricant, and when it exceeds 80% by weight, it does not solidify.
The blending ratio of the liquid rubber is 5 to 45% by weight, preferably 9 to 42% by weight, based on the entire mixture. When it is less than 5% by weight, it does not solidify, so it does not have a function as a foamed solid lubricant. When it is more than 45% by weight, the supply of the lubricant is small and it does not function as a foamed solid lubricant.

  In the first foamed solid lubricant, the expansion ratio is preferably 1.1 to 50 times, more preferably 1.1 to 10 times. When the expansion ratio is less than 1.1 times, the bubble volume is small and deformation cannot be allowed when external stress is applied. If it exceeds 50 times, it will be difficult to obtain the strength to withstand external stress.

  Moreover, in order to accelerate the curing rate of the first foamed solid lubricant, a tertiary amine catalyst, an organometallic catalyst, or the like can be used. Examples of the tertiary amine catalyst used include monoamines, diamines, triamines, cyclic amines, alcohol amines, ether amines and the like. Examples of the organometallic catalyst include stanaoctaate, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin mercaptide, dibutyltin thiocarboxylate, dibutyltin maleate, dioctyltin dimercaptide, dioctyltin thiocarboxylate and the like. Moreover, you may mix and use these multiple types for the purpose of adjusting the balance of reaction.

The urethane prepolymer that can be used as the resin component of the second foamed solid lubricant in the present invention is obtained by reacting a compound having an active hydrogen group with a polyisocyanate, and the isocyanate group may be a molecular chain terminal, or It may be contained at the end of the side chain branched from the molecular chain. The urethane prepolymer may have a urethane bond in the molecular chain.
Depending on the type of monomer (= compound having an active hydrogen group) to be reacted, it is classified into caprolactone, ester and ether. Ether ethers include Takenate L-1170 (Mitsui Chemical Polyurethane), L-1158 (Mitsui Chemical Polyurethane), and Coronate 4090 (Nippon Polyurethane). Coronate 4047 (manufactured by Nippon Polyurethane Co., Ltd.) is used as the ester system, and Takenate L-1350 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), Takenate L-1680 (manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.), and Sianaprene 7-QM are used as caprolactones. (Manufactured by Mitsui Chemicals Polyurethane), Plaxel EP1130 (manufactured by Daicel Chemical Industries) and the like.
Moreover, the oligomer and prepolymer compound which modified the terminal group into the isocyanate group can also be used. Examples of such a compound include a terminal isocyanate-modified polyether polyol and an isocyanate-modified product of a hydroxyl group-terminated polybutadiene. Examples of the terminal isocyanate-modified polyether polyol include Coronate 1050 (manufactured by Nippon Polyurethane Co., Ltd.). Moreover, poly-bd MC50 (made by Idemitsu Kosan Co., Ltd.) and poly-bd HTP9 (made by Idemitsu Kosan Co., Ltd.) are mentioned as the isocyanate modified body of hydroxyl-terminated polybutadiene.
These urethane prepolymers can be used in a mixture of two or more depending on the intended mechanical properties.

As the second foamed solid lubricant, a urethane prepolymer having an isocyanate group content of 2 wt% or more and less than 6 wt% can be used. If the isocyanate group (NCO) content is less than 2% by weight, it will be difficult to achieve both foamability and elasticity, and if it is more than 6% by weight, the hardness will be too high and the rebound resilience will increase and deformation due to external force will occur. It becomes easy to generate heat when receiving.
Moreover, the isocyanate group can use the block isocyanate etc. which blocked the isocyanate group with blocking agents, such as phenols, lactams, alcohols, and oximes.

The curing agent for curing the urethane prepolymer is preferably a compound having active hydrogen, and examples thereof include a polyamino compound having a functional group as an amino group and a polyol compound having a functional group as a hydroxyl group.
Polyamino compounds include 3,3'-dichloro-4,4'-diaminodiphenylmethane (hereinafter referred to as MOCA), 3,3'-dimethyl-4,4'-diaminodiphenylmethane, and 3,3'-dimethoxy-4. , 4'-diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyl-5,5'-dimethyldiphenylmethane, trimethylene-bis- (4-aminobenzoate), bis (methylthio) -2,4- Aromatics typified by toluenediamine, bis (methylthio) -2,6-toluenediamine, methylthiotoluenediamine, 3,5-diethyltoluene-2,4-diamine, 3,5-diethyltoluene-2,6-diamine Examples include polyamino compounds.

  Among the polyamino compounds, aromatic amino compounds are preferable because of low cost and excellent physical properties, and aromatic diamino compounds having a substituent at the position adjacent to the amino group are particularly preferable. In the 2nd foaming solid lubricant, since it passes through the process of hardening with foaming, it is thought that the reactivity of an amino group is suppressed by the substituent of an adjacent position.

  When the urethane prepolymer is cured with a polyamino compound, it becomes a foamed solid lubricant having urethane and urea bonds in the molecule. By generating urea bonds, the urethane bond density in the molecule is lowered, and elongation and impact resilience are improved. Moreover, rigidity can be provided by generating a urea bond.

  Examples of the polyol compound include low molecular polyols such as 1,4-butane glycol and trimethylolpropane, polyether polyols, castor oil polyols, and polyester polyols. Among the polyol compounds, polyether polyol and trimethylolpropane are preferable.

The ratio of the isocyanate group (—NCO) contained in the urethane prepolymer and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio when the functional group is an amino group or a hydroxyl group (functional group of the curing agent). /NCO)=1/(1.1 to 2.5).
The ratio of the isocyanate group contained in the urethane prepolymer, the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent, and the hydroxyl group of water (—OH) as the foaming agent, Flexibility, elasticity, etc. are determined. When the amino group (—NH ₂ ) or hydroxyl group (—OH) of the curing agent is reacted with the isocyanate group (—NCO) of the urethane prepolymer in an equivalent amount, an isocyanate group (—NCO) that reacts with water as the foaming agent is formed. Since it will disappear, the range of (functional group of curing agent / NCO) = 1 / (1.1 to 2.5) is preferable. Moreover, the ratio of the hydroxyl group of water which is a foaming agent and the functional group of a hardening | curing agent is the range of (hydroxyl group of water / functional group of a hardening | curing agent) = 1 / (0.7-2.0) by an equivalent ratio.
If the amount of the curing agent is less than the above range, not only the physical properties such as the strength of the foamed solid lubricant are remarkably lowered, but also the urethane elastomer may not be cured.

The lubricating component that can be used in the second foamed solid lubricant can be used as long as it does not dissolve the solid component that forms the foam, like the first foamed solid lubricant. As the lubricating component, for example, lubricating oil, grease, wax or the like can be used alone or in combination. Particularly preferred are hydrocarbon-based lubricants, hydrocarbon-based greases, or mixtures of hydrocarbon-based lubricants and hydrocarbon-based greases.
As the hydrocarbon-based lubricant, the same one as the first foamed solid lubricant can be used. In addition, ester synthetic oils, ether synthetic oils, fluorine oils, silicone oils and the like can also be used. These can be used alone or as a mixed oil.
As the grease, in addition to the grease similar to the first foamed solid lubricant, a grease based on ester synthetic oil, ether synthetic oil, GTL base oil, fluorine oil, silicone oil or the like can be used.
In addition, the same hydrocarbon-based synthetic wax, polyethylene wax, higher fatty acid ester-based wax, higher fatty acid amide-based wax, ketone / amines, hydrogenated oil, and the like as the first foamed solid lubricant may be used. it can.

As the foaming agent for foaming the second foamed solid lubricant, since an isocyanate compound is used as a raw material, it is preferable to use water that reacts with the isocyanate compound to generate carbon dioxide gas.
Moreover, in order to accelerate the curing rate of the second foamed solid lubricant, the above-described tertiary amine catalyst, organometallic catalyst, or the like can be used.

The second foamed solid lubricant is obtained by foaming and curing a mixture containing the lubricating component, the resin component, the curing agent, and the foaming agent.
The blending ratio of the lubricating component is 30 to 70% by weight, preferably 40 to 60% by weight, based on the entire mixture. If the lubricating component is less than 30% by weight, the supply amount of lubricating oil or the like is so small that it cannot function as a foamed solid lubricant, and if it exceeds 70% by weight, it may not solidify.

  The open cell ratio of the second foamed solid lubricant after foaming is 50% or more, preferably 50% or more and 90% or less. When the open cell ratio is less than 50%, the ratio of the resin component (solid component) lubricating oil temporarily taken up into the closed cells increases and may not be supplied to the outside when necessary. If it exceeds 90%, the oil retention of the lubricant will decrease and the amount of lubricant released will increase, which will be disadvantageous for long-term use, and the strength (durability) of the foamed solid lubricant itself will decrease. There is a fear.

The open cell ratio of the second solid foam lubricant can be calculated by the following procedure.
(1) The foamed solid lubricant that has been foam-cured is cut into an appropriate size to obtain sample A. The weight of sample A is measured.
(2) A is soxhlet washed (solvent: petroleum benzine) for 3 hours. Thereafter, the sample is left in a thermostatic bath at 80 ° C. for 2 hours to completely dry the organic solvent, and sample B is obtained. The weight of sample B is measured.
(3) The open cell ratio is calculated by the following procedure.
Open cell ratio = (1− (weight of resin component of sample B−weight of resin component of sample A) / weight of lubricating component of sample A) × 100
The resin component weight and the lubrication component weight of Samples A and B are calculated by multiplying the weights of Samples A and B by the composition charge ratio.
Lubricating components taken into discontinuous closed cells are not released to the outside by Soxhlet cleaning for 3 hours, so the weight of sample B is not reduced. The open cell ratio can be calculated as a result of the release of the lubricating component.

The first and second foamed solid lubricants may contain various additives such as pigments, antistatic agents, flame retardants, antifungal agents, reinforcing agents, inorganic fillers, anti-aging agents, and fillers as necessary. Can be added. Examples of the reinforcing agent include carbon black, white carbon, colloidal silica, and examples of the inorganic filler include calcium carbonate, barium sulfate, talc, clay, and meteorite powder.
In addition, solid lubricants such as molybdenum disulfide and graphite, friction modifiers such as organic molybdenum, oily agents such as amines, fatty acids and oils, antioxidants such as amines and phenols, petroleum sulfonates, dinonylnaphthalene sulfone Rust inhibitors such as nates and sorbitan esters, extreme pressure agents such as sulfur and sulfur-phosphorus, antiwear agents such as organic zinc and phosphorus, metal deactivators such as benzotriazole and sodium nitrite, polymethacrylate, polystyrene Various additives such as a viscosity index improver such as

For the first and second foamed solid lubricants, it is preferable to use a reactive impregnation method in which a foaming reaction and a curing reaction are simultaneously performed in the presence of a lubricating component such as a lubricating oil. It is desirable to achieve both simultaneously. This is because the lubricant is uniformly impregnated into the foam formed in the foam during the foam formation stage, and the lubricant is occluded in the foamed / cured solid component, so that the lubricant is highly filled and the material properties It is thought that the optimization of both is compatible.
On the other hand, after the foam is manufactured in advance, the post-impregnation method in which the lubricant is impregnated does not have sufficient lubricant holding power, and the lubricant is released in a short period of time and supplied when used for a long time. It becomes insufficient.

A method of mixing the mixture containing the lubricating component, the resin component, the curing agent, and the foaming agent is not particularly limited, and a commonly used agitator such as a Henschel mixer, a ribbon mixer, a juicer mixer, a mixing head, or the like. Can be mixed using.
Since the mixture is rapidly foamed and cured by the curing agent and the foaming agent, it is desirable to add the curing agent and the other components except the foaming agent to the stirrer and finally the curing agent and the foaming agent.
It is desirable that the above mixture use a surfactant such as a commercially available silicone-based foam stabilizer to uniformly disperse each raw material molecule. Further, the surface tension can be controlled by the type of the foam stabilizer, and the type of the generated bubbles can be controlled to open cells or closed cells. Examples of such surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, silicone surfactants, and fluorine surfactants.

In the rolling bearing for the CT scanner of the present invention, the foamed solid lubricant may be foamed and cured after pouring a mixture containing a lubricating component and a resin component into the bearing, or may be cut after foaming and curing at normal pressure. It can be post-processed to the desired shape by grinding or the like and incorporated into the bearing.
It is possible to easily fill any part in a bearing having a complicated shape, and there is no need for a molding die or a grinding process for obtaining a foamed molded product. -It is preferable to adopt a method of pouring into the bearing before curing and foaming and curing in the bearing. By adopting this method, the manufacturing process is simplified and the cost can be reduced.

  It is preferable that the bubbles to be generated when foamed by foaming at the time of foaming / curing are open cells that communicate with each other, and the lubricating component can be directly removed from the surface of the resin via the open cells by external stress. This is to supply. In the case of closed cells where the bubbles do not communicate with each other, the entire amount of lubricating oil in the solid component is temporarily isolated in the closed cells, making it difficult to move between the bubbles. May not be supplied.

Examples 1 to 15 and Comparative Examples 1 to 4
The lubricating components, liquid rubber, curing agent, foaming agent, and catalyst used in Examples 1 to 15 and Comparative Examples 1 to 4 are shown below. In addition, () represents an abbreviation in the table.
Lubricating component Lubricating oil (lubricating oil): Turbine 100 (manufactured by Nippon Oil Corporation)
Lubricating grease (Grease 1): NTG2218M (manufactured by Kyodo Yushi Co., Ltd.)
Liquid rubber Hydroxyl-terminated polybutadiene (PBOH1): Poly-bd R45HT (hydroxyl value: 46.6 mg KOH / g, number average molecular weight: 2,800, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polybutadiene (PBOH2): Poly-bd R15HT (hydroxyl value: 102.7 mg KOH / g, number average molecular weight: 1,200, manufactured by Idemitsu Kosan Co., Ltd.)
Hydroxyl-terminated polyisoprene (PipOH): Poly-ip (hydroxyl value: 46.6 mg KOH / g, number average molecular weight: 2,500, manufactured by Idemitsu Kosan Co., Ltd.)
Hydrogenated hydroxyl-terminated polyisoprene (HPipOH): Epol (hydroxyl value: 50.5 mg KOH / g, number average molecular weight: 2,500, manufactured by Idemitsu Kosan Co., Ltd.)
Curing agent Isocyanate compound (TDI): Coronate T-80 (manufactured by Nippon Polyurethane Co., Ltd.)
Elastomer 1 (UE1): Coronate 4090 (4.4 NCO% made by Nippon Polyurethane)
Elastomer 2 (UE2): Plaxel EP1130 (3.3 NCO% manufactured by Daicel Chemical Industries)
Foaming agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (Catalyst 1) DM70 (manufactured by Tosoh Corporation)

Mix well the compounding materials except the curing agent (isocyanate) at the blending ratios shown in Tables 1 to 3, and finally add 40 g of the mixture that was quickly mixed by adding the curing agent to a polytetrafluoroethylene resin container (70 mm in diameter). × Height 150 mm). After a few seconds, the foaming reaction started and allowed to stand at room temperature for several hours to be cured to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam in which oil oozes out when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Further, when not cured as a foam, cases where the lubricating oil does not separate or release are marked with “x” and are also shown in Tables 1 to 3.
In addition, the test piece evaluated as “◯” showed no oil oozing even when it was stretched by 20% in the cylindrical axis direction of the test piece.

As shown in Tables 1 to 3, the foamed solid lubricants of Examples 1 to 15 are elastic rubber foams in which oil oozes out when a corresponding force is applied when pressed with a finger. Although it was recognized as an excellent foamed solid lubricant, in Comparative Examples 1 to 4, it was found that although foamed, it did not partially solidify and function as a foamed solid lubricant.
Next, the foamed solid lubricant components of Examples 1 to 15 are injected into the bearing space surrounded by the inner and outer rings 2 and 3 and the rolling elements 4 of the rolling bearing 1 for CT scanner shown in FIG. And allowed to harden for several hours to obtain a rolling bearing for a CT scanner in which a foamed solid lubricant was enclosed.
In this rolling bearing for CT scanner, since the foamed solid lubricant was sealed inside the bearing, there was no leakage of the lubricant and the generation of abnormal noise could be prevented or suppressed.

The lubricating components, urethane prepolymers, curing agents, foaming agents, and catalysts used in Examples 16 to 35 and Comparative Examples 5 to 7 are shown below. In addition, () represents an abbreviation in the table.
Lubricating component Lubricating oil (lubricating oil 1): Turbine 100 (paraffinic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 2): Crisef 150 (Naphthenic mineral oil, manufactured by Nippon Oil Corporation)
Lubricating oil (lubricating oil 3): Sinfluid 801 (poly-α-olefin, manufactured by Nippon Steel Chemical Co., Ltd.)
Lubricating grease (Grease 2): Pyronic Universal N6C (manufactured by Nippon Oil Corporation)
Urethane prepolymer Caprolactan-based urethane prepolymer 1 (prepolymer 1): Plaxel EP1130 (NCO 3.3%, manufactured by Daicel Chemical Industries)
Ether-based urethane prepolymer (Prepolymer 2): Coronate 4090 (NCO 4.3%, manufactured by Nippon Polyurethane)
Ester urethane prepolymer (Prepolymer 3): Coronate 4047 (NCO 4.3%, manufactured by Nippon Polyurethane Co., Ltd.)
Caprolactan urethane prepolymer (Prepolymer 4): Takenate L-1350 (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 5): Takenate L-1170 (NCO 2.4%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 6): Takenate L-1680 (NCO 3.2%, manufactured by Mitsui Chemicals Polyurethanes)
Caprolactan urethane prepolymer (Prepolymer 7): Cyanaprene 7-QM (NCO 2.3%, manufactured by Mitsui Chemicals Polyurethanes)
Ether-based urethane prepolymer (Prepolymer 8): Takenate L-1158 (NCO 4.4%, manufactured by Mitsui Chemicals Polyurethanes)
Hardener MOCA (MOCA): Iharacamine MT (manufactured by Ihara Chemical)
Trimethylene-bis- (4-aminobenzoate) (CUA-4): CUA-4 (manufactured by Ihara Chemical)
Mixture of bis (methylthio) -2,4-toluenediamine, bis (methylthio) -2,6-toluenediamine and methylthiotoluenediamine (Etacure 300): Etacure 300 (manufactured by Albemarle)
Trimethylolpropane: Reagent blowing agent (foaming agent) Ion exchange water foam stabilizer (foam stabilizer) SRX298 (manufactured by Toray Dow)
Catalyst (Catalyst 1) DM70 (manufactured by Tosoh Corporation)

Examples 16-18, 21, 22, 24, 25, 27-32, 34-35, Comparative Examples 5-7
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratios shown in Tables 4 to 6. Next, MOCA dissolved at 120 ° C. was put into a beaker and well stirred. Subsequently, an amine catalyst and a foaming agent (only Comparative Example 6 had no foaming agent) were added and stirred. After a few seconds, the foaming reaction started and allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. In other cases, “Δ” mark or comments are also shown in Tables 4 to 6.
Further, the open cell ratio was measured by the above-described method, and the centrifugal oil separation evaluation was measured by the following method. The results are shown in Tables 4-6.
Centrifugal oil separation evaluation test Centrifugal oil separation was measured in order to examine the sustained release of the lubricant. Centrifugal oil separation showed the oil reduction rate relative to the oil filling amount when rotated for 1 hour under the conditions of a rotor radius of 75 mm and a rotation speed of 1500 rpm.

Example 19
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 100 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratio shown in Table 4. Next, trimethylene-bis (4-aminobenzoate) dissolved at 140 ° C. was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started and allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 4.

Examples 20, 26, 33
In a polytetrafluoroethylene beaker (diameter 70 mm × height 150 mm) at 80 ° C., the raw materials excluding the curing agent, amine catalyst and blowing agent were mixed well in the blending ratios shown in Tables 4 to 6. Next, Etacure 300 was put into a beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started and allowed to stand at 100 ° C. for 30 minutes to cure to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Are also shown in Tables 4-6.

Example 23
In a polytetrafluoroethylene beaker (diameter: 70 mm × height: 150 mm) at 100 ° C., raw materials excluding the curing agent, amine catalyst and foaming agent were mixed well at the blending ratio shown in Table 5. Next, trimethylolpropane was put into the beaker and stirred well. Subsequently, an amine catalyst and a blowing agent were added and stirred. After a few seconds, the foaming reaction started, and it was left to cure at 100 ° C. for 30 minutes to obtain a cylindrical test piece. This test piece was observed visually and using an optical microscope. Evaluated as an excellent foamed solid lubricant that is an elastic rubber foam that exudes oil when a force of 30 N is applied to the specimen in the direction of the cylinder axis of the specimen. Is also shown in Table 5.

As shown in Tables 4 to 6, Examples 16 to 35 are elastic rubber foams in which oil oozes out when a corresponding force is applied when pressed with a finger, and excellent foam solid lubrication. In Comparative Example 5, it was found that although foamed, it did not partially solidify, and in Comparative Example 6, the resin component and the lubricant were separated and did not function as a foamed solid lubricant. . Comparative Example 7 lacked elasticity. Further, in Examples 16 to 35, it was found that the lubricant component was gradually released under the centrifugal force (without immediately leaving the foam).
Next, the foamed solid lubricant components of Examples 16 to 35 are injected into the bearing space surrounded by the inner and outer rings 2 and 3 and the rolling elements 4 of the rolling bearing 1 for CT scanner shown in FIG. And allowed to cure at 100 ° C. for 30 minutes to obtain a rolling bearing for a CT scanner in which a foamed solid lubricant was enclosed.
In this rolling bearing for CT scanner, since the foamed solid lubricant was sealed inside the bearing, there was no leakage of the lubricant and the generation of abnormal noise could be prevented or suppressed.

  Since the rolling bearing for the CT scanner of the present invention encloses the foamed solid lubricant in the bearing internal space, it is possible to prevent the occurrence of sliding noise and frictional noise due to the leakage of the lubricating component to the outside of the bearing and rotation. For this reason, it can utilize suitably for the rolling bearing for CT scanners.

It is sectional drawing which shows one Example of the rolling bearing for CT scanners of this invention. It is sectional drawing which shows the outline of CT scanner apparatus. It is sectional drawing which shows an example of the conventional rolling bearing for CT scanners. It is a front view which shows the holder for bearings of the conventional CT scanner apparatus.

Explanation of symbols

1,11 Rolling bearing for CT scanner 2,12 Inner ring 3,13 Outer ring 4,14 Ball (rolling element)
5, 15 Cage 6a, 16a Seal member 6b, 16b Seal member 7a, 17a Fixed mount bolt 7b, 17b Rotating mount bolt 8 Foamed solid lubricant 9 Spacer 21 X-ray tube device 22 Wedge filter 23 Slit 24 Subject 25 Detection 26 Fixed frame 27 Rotating frame

Claims (12)

It comprises an inner ring, an outer ring, and a plurality of rolling elements incorporated between the races of these inner and outer rings, and a foamed solid lubricant is enclosed in a bearing space surrounded by the inner and outer rings and the rolling elements, A rolling bearing for a CT scanner that rotatably supports a rotating base that rotates around a subject,
A rolling bearing for a CT scanner, wherein the foamed solid lubricant is a foamed solid lubricant obtained by foaming and curing a mixture containing a lubricant component, a resin component, a curing agent, and a foaming agent.   2. The rolling bearing for a CT scanner according to claim 1, wherein the foamed solid lubricant is sealed between at least an outer diameter surface of a cage for holding the rolling elements and an inner diameter surface of the outer ring. The lubricating component is at least one lubricating component selected from a hydrocarbon-based lubricating oil and a hydrocarbon-based grease;
The resin component is a liquid rubber in which the polymer main chain is composed of hydrocarbons and has hydroxyl groups in an amount such that the hydroxyl value is 25 to 110 mg KOH / g at the ends of the main chain.
The curing agent is an organic compound having an isocyanate group in the molecule,
The blowing agent is water;
The ratio of the liquid rubber and the curing agent is such that the hydroxyl group contained in the liquid rubber and the isocyanate group contained in the curing agent are in an equivalent ratio of (OH / NCO) = 1 / (1.0 to 2.0). ,
3. The rolling bearing for a CT scanner according to claim 1, wherein the mixture includes 40 to 80 wt% of the lubricating component and 5 to 45 wt% of the liquid rubber with respect to the entire mixture.   The liquid rubber is a hydroxyl group-terminated diene polymer having a number average molecular weight of 1000 to 3500 having a hydroxyl group at the main chain end of a polymer of butadiene or isoprene, or a modified hydroxyl group-terminated diene polymer obtained by hydrogenating the diene polymer. The rolling bearing for a CT scanner according to claim 3, wherein   The organic compound having an isocyanate group in the molecule is a prepolymer having two or more isocyanate groups in the molecule and a ratio of isocyanate groups of 2.5 to 5.0 NCO%. The rolling bearing for CT scanners of Claim 4.   The rolling bearing for a CT scanner according to claim 3 or 4, wherein the organic compound having an isocyanate group in the molecule is an aromatic polyisocyanate. The lubricating component is at least one lubricating component selected from lubricating oil and grease;
The resin component is a urethane prepolymer having an isocyanate group content of 2 wt% or more and less than 6 wt%,
The blowing agent is water;
3. The CT scanner according to claim 1, wherein the mixture includes 30 to 70% by weight of the lubricating component with respect to the entire mixture, and an open cell ratio after foaming is 50% or more. 4. Rolling bearing.   8. The rolling for CT scanner according to claim 7, wherein the urethane prepolymer is at least one urethane prepolymer selected from an ester urethane prepolymer, a caprolactone urethane prepolymer, and an ether urethane prepolymer. bearing.   The ratio of the isocyanate group and the functional group of the curing agent that reacts with the isocyanate group is an equivalent ratio (functional group of the curing agent / NCO) = 1 / (1.1 to 2.5). The rolling bearing for CT scanners of Claim 7 or Claim 8.   The ratio of the hydroxyl group of the water to the functional group of the curing agent is an equivalent ratio (water hydroxyl group / functional group of the curing agent) = 1 / (0.7 to 2.0). The rolling bearing for CT scanners as described in any one of Claim thru | or 9.   The rolling bearing for a CT scanner according to any one of claims 7 to 10, wherein the curing agent is an aromatic polyamino compound. The rolling bearing for a CT scanner according to claim 11, wherein the aromatic polyamino compound is an aromatic polyamino compound having a substituent at a position adjacent to an amino group.

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