JP2019060448A - Roller bearing and lubrication structure for roller bearing - Google Patents

Abstract

To provide a roller bearing which prevents occurrence of burning or fracture even under such a high-speed rotation condition that a dm n value becomes equal to or more than 100×10.SOLUTION: An angular ball bearing 1 is configured by comprising: an inner ring 2 and an outer ring 3; multiple balls 4 which are interposed between the inner and outer rings; and a holder 5 which holds the balls 4. The angular ball bearing 1 is used under high-speed rotation in which a dm n value is equal or more than 100×10, and lubricated by air oil lubrication or oil mist lubrication. The holder 5 is configured by injection-molding a resin composition. The resin composition is a composition containing a polyamide resin consisting of a dicarboxylic acid component and a diamine component as a base resin and blending a fibrous reinforcement material therewith. The dicarboxylic acid component contains terephthalic acid as a main component, and the diamine component contains 1,10-decane diamine as a main component. As the fibrous reinforcement material, a glass fiber is contained in 15 to 50 mass% or a carbon fiber is contained in 10 to 35 mass% with respect to the entire resin composition.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rolling bearing for use in automobiles, motors, machine tools, etc., and a lubricating structure for rolling bearings.

  A rolling bearing comprises an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements in a rollable manner. Those made of iron are used. However, when the rotational speed of the rolling bearing is increased, the friction between the rolling element and the cage in the iron cage increases due to the sliding contact between the rolling element and the cage, and the temperature rise of the bearing becomes large. there were. Therefore, it is considered effective to use, as the material of the cage, a synthetic resin that is superior to iron in terms of self-lubricity, low friction characteristics, light weight, and the like. As a synthetic resin, generally, polyamide 6 resin, polyamide 66 resin, polyamide 46 resin, etc. are used, and those containing glass fiber and reinforcing them as needed are used (see Patent Document 1). Further, cages using a heat-resistant polyamide resin have also been proposed for the purpose of further improving dimensional stability, heat resistance and chemical resistance (see Patent Documents 2, 3 and 4).

Japanese Patent Laid-Open No. 2000-227120 JP 2001-317554 A JP, 2006-207684, A JP, 2016-121735, A

  When rotating a rolling bearing incorporating a resin cage at high speed, the centrifugal force generated by the high speed rotation acts on the cage, and as a result, the cage may be deformed. When the cage is deformed, the friction between the cage and the rolling elements held by the cage becomes large, which causes the rolling bearing to generate heat. In particular, when the cage is a rolling element guiding system, the cage guides the rolling elements, so the frictional heat between the rolling element and the cage during high speed rotation may cause the pocket portion of the cage to melt. There is. Therefore, it is considered that the use rotational speed is limited.

  In addition, when the cage is deformed, contact with the outer ring also occurs, and the frictional heat due to the contact may cause the resin to melt and the rolling bearing may not rotate (seize). Therefore, it is required that the resin cage incorporated in the rolling bearing used at high speed rotation in this way is not deformed by mechanical and / or thermal stress.

However, the mechanical properties of the synthetic resin largely change at the boundary of the glass transition temperature, and the strength and the elastic modulus decrease at high temperatures. As for the polyamide 66 resin and the polyamide 46 resin which are general cage materials described in Patent Document 1, their glass transition temperatures are about 50 ° C. and about 80 ° C., respectively, and at temperatures above that, as described above The generation of deformation due to centrifugal force, increase in heat generation due to sliding friction between the cage and the rolling elements, and a further rise in bearing temperature may cause contact between the cage and the outer ring, which may lead to seizure or cage failure. . Therefore, for example, in the case of using at high speed rotation where dm · n value (product of pitch circle diameter dm of rolling element and orbital ring rotational speed n) is 60 × 10 ⁴ or more (further, 80 × 10 ⁴ or more) , It was difficult to prevent damage due to burn-in and cage damage. In addition, polyamide 66 resin and polyamide 46 resin have high water absorption, and accordingly the cage dimensions change, so it is necessary to use dimensional control in a moisture absorbed state. In addition, the strength and elastic modulus after moisture absorption are greatly reduced compared to before moisture absorption.

  On the other hand, the polyamide 9T resin described in Patent Documents 2 and 3 has a glass transition temperature of 125 ° C., which is higher than the glass transition temperatures of the above-described polyamide 66 resin and polyamide 46 resin. However, even in the case of polyamide 9T resin, the cage temperature may become higher than the glass transition temperature if the lubrication condition is deteriorated due to any factor with respect to the temperature rise under high-speed rotation conditions, and problems such as deformation may occur. There is.

  In addition, since the polyamide 9T resin is an aromatic polyamide, the water absorbency is low as compared with aliphatic polyamides such as polyamide 66 resin and polyamide 46 resin. However, in a cage made of a resin manufactured by injection molding, a weld portion formed in a region where the resin composition joins at the time of molding is always present, and polyamide 9T resin has a high elastic modulus and a low toughness. As a result, stress concentration on the weld occurs at the time of use, and cracking at the weld tends to occur, which may lower the strength of the cage.

In these points, Patent Document 2 proposes a cage using a polyamide 9T resin, but has not suggested its seizure resistance performance. Further, in Patent Document 3, although there is a description up to about 90 × 10 ⁴ as a condition that the dm · n value is 60 × 10 ⁴ or more with respect to temperature rise, performance of rotational speed higher than that is not suggested.

Further, in the case of using a polyamide resin having terephthalic acid and 1,10-decanediamine as main components described in Patent Document 4, a bearing temperature test in which an angular contact ball bearing is rotated to a dm · n value of 80 × 10 ⁴ Although implemented, no further rotational speed performance is suggested.

The present invention has been made to address such problems, and a rolling bearing that does not cause seizure or breakage even under high-speed rotation conditions where dm · n value is 100 × 10 ⁴ or more, and the rolling An object of the present invention is to provide a lubrication structure using a bearing.

The rolling bearing of the present invention is a rolling bearing comprising an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements, wherein the rolling bearing is dm · n value A rolling bearing used at high speed rotation of 100 × 10 ⁴ or more and lubricated by air oil lubrication or oil mist lubrication, and the above cage is formed by injection molding of a resin composition, and the above resin The composition is a composition comprising a polyamide resin comprising a dicarboxylic acid component and a diamine component as a base resin, and a fibrous reinforcing material added thereto, wherein the dicarboxylic acid component comprises terephthalic acid as a main component, and the diamine The component is mainly composed of 1,10-decanediamine, and as the above-mentioned fibrous reinforcing material, 15 to 50% by mass of glass fibers or 10 of carbon fibers with respect to the whole resin composition. It is characterized by containing -35 mass%.

  The polyamide resin is characterized by having a melting point of 310 ° C. or more. Further, the above-mentioned cage is characterized in that it is a cage of inner ring guide system or outer ring guide system.

The rolling bearing is characterized in that it is used in a spindle device. Further, the rolling bearing is characterized in that the bearing is rotatable to a dm · n value of 300 × 10 ⁴ .

  The lubricating structure of the rolling bearing of the present invention is characterized by comprising the rolling bearing of the present invention and a nozzle member for discharging lubricating oil of air oil or oil mist toward the raceway surface of the inner ring of the rolling bearing.

Since the rolling bearing of the present invention is lubricated by air oil lubrication or oil mist lubrication, the stirring resistance of the lubricating oil inside the bearing is reduced, and a cooling effect by compressed air is also obtained. Therefore, the temperature rise inside the bearing accompanying high speed rotation can be suppressed. Furthermore, in the cage of the bearing, 15 to 50% by mass of glass fiber or carbon fiber in a predetermined polyamide resin in which the dicarboxylic acid component is terephthalic acid and the diamine component is 1,10-decanediamine respectively The resin composition obtained by blending 10 to 35% by mass of the resin composition is injection-molded, so that the rigidity (elastic modulus) is high, and deformation can be reduced even under high-temperature, high-speed rotation conditions. For this reason, even if it is used by high-speed rotation which dm * n value becomes 100 * 10 ⁴ or more, calorific value can be made small and a seizing and a damage can be prevented. In addition, since the dicarboxylic acid component is based on a polyamide resin having terephthalic acid as the diamine component and 1,10-decanediamine as the main component, the crystallization speed is very fast and the cycle time during molding is shortened. Can improve productivity.

  Since the above-mentioned polyamide resin as the base resin has a melting point of 310 ° C. or higher, compared with the polyamide 66 resin (melting point 267 ° C.) and polyamide 46 resin (melting point 295 ° C.) most frequently used as cage materials. Has very high heat resistance. Also, it has heat resistance equal to or higher than that of polyamide 9T resin (melting point 300 ° C.). Therefore, the deformation can be reduced even under the condition of high temperature and high speed rotation.

In addition, it is superior in oil resistance and chemical resistance to the above other polyamide resins, and can be used under more severe use conditions than conventional ones, such as high temperature and in oil. Further, the water absorption rate is also comparable to that of the polyamide 9T resin, and it is very small compared to the polyamide 66 resin and the polyamide 46 resin, and dimensional change due to water absorption and physical property deterioration can be suppressed as much as possible.

  Since the cage is an inner ring guide system or an outer ring guide system cage, friction between the rolling element and the cage can be reduced during high speed rotation as compared with the rolling element guide system, and heat generation associated therewith can be suppressed. it can.

The spindle device is used under high-speed rotation conditions such that the dm · n value is 100 × 10 ⁴ or more, for example. The rolling bearing of the present invention is suitable for use in a spindle device because it can be used without seizure or breakage even when the dm · n value is 100 × 10 ⁴ or more.

It is an axial direction fragmentary sectional view of an example of the rolling bearing of this invention. It is a perspective view which shows the holder | retainer of the rolling bearing of this invention. It is sectional drawing of the lubricating structure of the rolling bearing of this invention. It is a figure which shows the spindle apparatus which used the rolling bearing of this invention.

The present inventors diligently studied to obtain a rolling bearing that can be used stably even under high-speed rotation conditions, and by combining a cage made of a predetermined resin composition with a predetermined bearing lubrication system, 100 × It has been found that rolling bearings can be used without seizure even under high-speed rotation conditions of 10 ⁴ or more. The present invention is based on such findings.

  The cage used in the rolling bearing of the present invention is a cage made of resin, which is formed by injection molding of a resin composition. A resin composition used as a resin material is formed by using a predetermined polyamide resin as a base resin, and adding a predetermined amount of fibrous reinforcing material (glass fiber or carbon fiber) thereto.

  The polyamide resin used in the present invention comprises a dicarboxylic acid component and a diamine component, and is obtained by polycondensing dicarboxylic acid and diamine constituting each component. The dicarboxylic acid component which comprises the said polyamide resin has a terephthalic acid as a main component. By using terephthalic acid as a main component, the polyamide resin is excellent in high temperature rigidity and the like. Moreover, the diamine component which comprises the said polyamide resin has 1, 10- decane diamine as a main component. 1,10-decanediamine is a linear aliphatic diamine. Since both terephthalic acid and 1,10-decanediamine have high symmetry in chemical structure, a polyamide resin having high crystallinity can be obtained by using these as the main component.

  In the present invention, as described above, the linear 1, 10-decanediamine having 10 carbon atoms is used as the main component of the diamine component constituting the polyamide resin. Since the carbon number of the monomer unit of the diamine component as the main component is 10 and is an even number, it has a more stable crystal structure and improves the crystallinity (even-odd effect) as compared to the case of an odd number. Moreover, when carbon number of the diamine component made into a main component is eight or less, there exists a possibility that melting | fusing point of the said polyamide resin may exceed a decomposition temperature. When the carbon number of the diamine component is 12 or more, the melting point of the polyamide resin is lowered, and there is a possibility that the cage may be deformed when used under high temperature, high speed conditions. In the case of a diamine having 9 and 11 carbon atoms, the crystallinity may be insufficient due to the above-described even-odd effect of the polyamide resin.

  The said polyamide resin is good also as what substituted a part of terephthalic acid which is a dicarboxylic acid component, and 1, 10- decane diamine which is a diamine component by another copolymerization component. However, since the melting point and crystallinity decrease when the amount of other copolymerization components increases, the total amount of terephthalic acid and 1,10-decanediamine as main components is the total number of moles (100 mol%) of the raw material monomers. On the other hand, it is preferable to set it as 95 mol% or more. Further, it is particularly preferable to be composed substantially only of terephthalic acid and 1,10-decanediamine, and to be substantially free of other copolymerization components.

  Examples of dicarboxylic acid components other than terephthalic acid used as other copolymerization components include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecane Aliphatic dicarboxylic acids such as diacid, alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, and aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and naphthalenedicarboxylic acid. Moreover, as diamine components other than 1, 10- decane diamine used as another copolymerization component, 1, 2- ethane diamine, 1, 3- propane diamine, 1, 4- butane diamine, 1, 5- pentane diamine Aliphatic diamines such as 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,11-undecanediamine, 1,12-dodecanediamine, cyclohexane diamine, etc. And aromatic diamines such as xylylene diamine. The polyamide resin may be copolymerized with a lactam such as caprolactam.

  The weight average molecular weight of the polyamide resin is preferably 15,000 to 50,000, and more preferably 26,000 to 50,000. If the weight average molecular weight of the polyamide resin is less than 15,000, the rigidity of the resin is reduced, and the cage may be deformed at high speed rotation. On the other hand, when the weight average molecular weight of the polyamide resin exceeds 50,000, crystallization is delayed and the flowability at the time of injection molding is reduced. The relative viscosity of the polyamide resin is not particularly limited, but in order to facilitate the formation of the cage, 96 mass% sulfuric acid is used as a solvent, and the relative viscosity measured at 25 ° C. is 2 at a concentration of 1 g / dL. It is preferable to set it as .0 or more.

  It is preferable that the said polyamide resin is 310 degreeC or more in melting | fusing point. Although the upper limit is not particularly limited, it is preferable to set it to about 320 to 340 ° C. in consideration of molding processability and the like. Melting point is higher than other polyamide resins (polyamide 66 resin (267 ° C), polyamide 46 resin (295 ° C), polyamide 9T resin (300 ° C)) generally used as cage materials, and heat resistance is excellent Therefore, even if used at high temperature and high speed rotation, deformation, seizing, breakage, etc. of the cage can be prevented. The melting point is 20 ° C./min after lowering the temperature of the above polyamide resin from the molten state to 25 ° C. at a temperature drop rate of 20 ° C./min using a differential scanning calorimeter (DSC) under an inert gas atmosphere. It can be measured as the temperature (Tm) of an endothermic peak that appears when the temperature is raised at a temperature rising rate.

  The polyamide resin preferably has a glass transition temperature of 130 ° C. or higher. More preferably, it is 150 ° C. or higher. Because the glass transition temperature is higher than other polyamide resins (polyamide 66 resin (49 ° C), polyamide 46 resin (78 ° C), and polyamide 9T resin (125 ° C) generally used as cage materials, high temperature, Even when used at high-speed rotation, deformation of the cage can be suppressed, and heat generation due to sliding friction between the rolling elements and the cage can be reduced.Note that the glass transition temperature is inactive using a differential scanning calorimeter (DSC) After quenching the polyamide resin in a gas atmosphere, it can be measured as the temperature (Tg) of the middle point of the step-like endothermic peak that appears when the temperature is raised at a temperature rising rate of 20 ° C./min (JIS K7121).

Glass fiber or carbon fiber is used as a fibrous reinforcing material to be mixed with the above-mentioned polyamide resin as a base resin. The glass fiber is obtained by spinning from an inorganic glass whose main component is SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , CaO, MgO, Na ₂ O, K ₂ O, Fe ₂ O ₃ or the like. In general, alkali-free glass (E glass), alkali-containing glass (C glass, A glass) and the like can be used. In view of the influence on the polyamide resin, non-alkali glass is preferable. The alkali-free glass is a borosilicate glass which contains almost no alkali component in the composition. Since the alkali component is hardly contained, there is almost no influence on the polyamide resin, and the characteristics of the resin composition do not change. As glass fiber, Asahi Fiber Glass Co., Ltd. make: 03JAFT692, MF03MB120, MF06MB120 etc. are mentioned, for example.

  The carbon fiber can be used regardless of the kind of raw material such as polyacrylonitrile (PAN), pitch, rayon, lignin-povar mixture and the like. As pitch-based carbon fibers, for example, Kleha Co., Ltd .: KLECA M-101S, M-107S, M-101F, M-201S, M-207S, M-2007S, C-103S, C -106S, C-203S and the like. In addition, as PAN-based carbon fibers, for example, Toho Tenax Co., Ltd .: Vesphyt HTA-CMF0160-0H, HTA-CMF 0040-0 H, HTA-C6, HTA-C6-S, or Toray Co., Ltd .: Toreka MLD-30, MLD-300, T008, T010 etc. are mentioned.

  When using glass fiber as a fibrous reinforcing material, the compounding quantity sets it as 15-50 mass% with respect to the whole resin composition. When using a carbon fiber as a fibrous reinforcement, the compounding quantity sets it as 10-35 mass% with respect to the whole resin composition. By setting the glass fiber or the carbon fiber in the above range, the rigidity of the cage can be increased, deformation of the cage can be reduced even under conditions of high temperature and high speed rotation, and the calorific value can be reduced. Furthermore, glass fiber is used in consideration of securing the sufficient strength (tensile strength) of the weld portion when assembling the rolling bearing cage into a shape that is forcibly removed at the time of injection molding, or when assembling to the rolling bearing. In the case, 30 to 50% by mass is preferable with respect to the entire resin composition, and when carbon fiber is used, 20 to 35% by mass is preferable with respect to the entire resin composition.

  In the resin composition used in the present invention, additives other than the above-mentioned fibrous reinforcing material may be blended, if necessary, as long as the retainer function and the injection moldability are not impaired. As other additives, for example, a solid lubricant, an inorganic filler, an antioxidant, an antistatic agent, a mold release material and the like can be blended.

  The materials constituting the above resin composition are mixed, if necessary, with a Henschel mixer, a ball mixer, a ribbon blender, etc., and then melt-kneaded with a melt extruder such as a twin-screw kneader extruder to form molding pellets You can get In addition, the side feed may be adopted when the filler is melt-kneaded by a twin-screw extruder or the like. The holder is molded by injection molding using the molding pellets. At the time of injection molding, the resin temperature is made equal to or higher than the melting point of the above-mentioned polyamide resin, and the mold temperature is held below the glass transition temperature of the polyamide resin.

  Since the cage of the rolling bearing of the present invention is composed of a resin composition prepared by blending a predetermined amount of fibrous reinforcing material (glass fiber or carbon fiber) into a predetermined polyamide resin as described above, the melting point and the glass transition temperature are high. It exhibits excellent heat resistance, oil resistance, chemical resistance, dimensional stability, toughness and high mechanical properties. For this reason, the above cage is able to withstand long-term use under severe environmental conditions (high temperature atmosphere, conditions of contact with oil or chemicals, high speed rotation condition, high load condition, humid environment, etc.) such as high speed rotation range Become a container.

  Moreover, since the said resin composition has small water absorption, it can suppress the dimensional change and physical-property fall accompanying swelling by water absorption and absorption, and expansion. The above-mentioned cage is excellent in dimensional stability, and can be provided inexpensively as a cage for applications requiring accuracy.

In the polyamide resin used in the present invention, a plant-derived material may be used as the dicarboxylic acid component or the diamine component. For example, 1,10-decanediamine starting from castor oil can be used. By employing a biomass-derived material such as a plant, it is possible to reduce the substantial emission of carbon dioxide associated with the incineration disposal of the resin-made cage than in the case where the biomass-derived material is not used. Here, whether or not it is a vegetable plastic using a biomass-derived material can be determined by measuring the concentration of ¹⁴ C, which is a radioactive isotope, for carbon constituting the resin. ^Since the half life of ¹⁴ C is 5730 years, ¹⁴ C is not contained in carbon derived from fossil resources that is considered to be generated after 10 million years or more. From this, if ¹⁴ C is contained in the resin, it can be determined that at least a biomass-derived material is used.

  The rolling bearing of the present invention and a cage used for the bearing will be described based on FIGS. 1 and 2. FIG. FIG. 1 is a partial axial sectional view of an angular ball bearing which is an example of the rolling bearing of the present invention, and FIG. 2 is a perspective view of a cage (machined type) in the rolling bearing of FIG.

  As shown in FIG. 1, the angular ball bearing 1 comprises an inner ring 2 having a raceway surface 2a on the outer peripheral surface, an outer ring 3 having a raceway surface 3a on the inner peripheral surface, a raceway surface 2a of the inner ring 2 and a raceway surface of the outer ring 3 A ball 4 rolling between 3a and a cage 5 rotatably holding the ball 4 are provided. The inner ring 2 and the outer ring 3 are in contact with the ball 4 at a predetermined angle θ (contact angle) with respect to the radial center line, and can apply a radial load and an axial load in one direction. The cage 5 is of an outer ring guiding system, and has an outer ring guiding portion 5a guided by the outer ring 3 on a part of the outer peripheral surface of the cage. In the configuration of FIG. 1, the retainer 5 is guided to the outer ring 3 by the outer ring guide portion 5 a coming into contact with the inner peripheral surface of the outer ring 3. The guide type of the cage is not limited to the outer ring guide type, and may be the inner ring guide type.

  FIG. 2 shows a perspective view of the holder. As shown in FIG. 2, in the cage 5, a plurality of pocket portions 6 for storing balls, which are rolling elements, are provided in the annular cage main body 5 b at regular intervals in the circumferential direction.

In the rolling bearing of the present invention, as described above, since the cage is made of the above resin composition, it is a cage that can withstand long-time use even at high speed rotation. However, it is preferable to use a rolling bearing that can be used without seizing even at a high speed of 100 × 10 ⁴ or more, for example, because of the recent demand for higher speed of the device. Under higher speed rotation conditions, it is considered important to properly supply the lubricating oil to the bearing members.

  In this regard, the rolling bearing of the present invention is a bearing that is lubricated by oil mist lubrication or air oil lubrication, and thus is more suitable for high speed rotation. In the above-described lubrication method, since the lubricating oil is discharged inside the bearing using compressed air, the lubricating oil can be properly supplied. Further, compared to grease lubrication using grease, the amount of lubricant inside the bearing can be reduced, and the agitation resistance of the lubricant inside the bearing can be reduced accordingly. Furthermore, in the above-described lubrication system, since compressed air is pumped to supply lubricating oil to the inside of the bearing, the cooling effect of the bearing by the compressed air can also be obtained. The cooling effect can suppress the temperature rise of the bearing. Thus, in the rolling bearing of the present invention, since the cage is made of the above resin composition and is further lubricated by oil mist lubrication or air oil lubrication, long time operation is possible without melting even under ultra high speed rotation conditions It becomes.

  FIG. 3 shows a lubrication structure in which the rolling bearing of the present invention and the nozzle member 7 for discharging air oil are combined. The nozzle member 7 is fitted to the inner peripheral surface of the housing 11 in which the angular ball bearing 1 is installed, and is provided adjacent to the outer ring 3. Further, an inner ring spacer 8 is provided adjacent to the inner ring 2 on the inner diameter side of the nozzle member 7. The nozzle member 7 internally has a lubricating oil flow path for guiding air oil supplied from an external air oil supply device (not shown) to the bearing space. The lubricating oil flow path includes a nozzle hole 9 whose tip is open toward the bearing space, and an inflow hole 10 communicating with the nozzle hole 9. The air oil supply device is a device for mixing lubricating oil and compressed air and delivering the air oil, and the housing 11 is provided with a lubricating oil supply passage 12 connecting the air oil supply device and the inflow hole 10.

During rotation of the angular ball bearing 1, air-oil from air-oil supply device is a predetermined amount (e.g. 0.01~0.03mm ³ / 3~10min) supplied at predetermined intervals. The air oil enters the inflow hole 10 of the nozzle member 7 from the lubricating oil supply passage 12 of the housing 11 and is jetted from the nozzle hole 9 toward the raceway surface 2 a of the inner ring 2. As a result, the raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3 are lubricated. The lubrication method is not limited to air oil lubrication, and oil mist lubrication may be used. In oil mist lubrication, lubrication is achieved by supplying a mixed gas for lubrication (oil mist), which is a mixture of atomized lubricating oil with compressed air, to a bearing.

  In FIG. 1 and FIG. 2, although the angular ball bearing was demonstrated as an example as a rolling bearing of this invention, the bearing type which can apply this invention is not limited to this, Other ball bearings, a tapered roller bearing, self-aligning roller It can be applied to bearings, needle roller bearings, etc.

As described above, the rolling bearing of the present invention can suppress the heat generation of the bearing even at high speed rotation, and is particularly suitable for high speed rotation applications. Specifically, the rolling bearing of the present invention can be used even with a dm · n value of 100 × 10 ⁴ or more. As a high-speed rotation application, for example, it is applied to a spindle device for a machine tool spindle.

  FIG. 4 shows an example of a spindle device for a machine tool spindle using the angular ball bearing 1. As shown in FIG. 4, the spindle device 21 has two angular contact ball bearings 1, and in each angular contact ball bearing 1, nozzle members 7 for discharging air oil are provided adjacent to each other. The two angular contact ball bearings 1 are positioned by the inner ring spacer 23 and the outer ring spacer 24 respectively disposed on the inner ring side and the outer ring side, and rotatably support the main shaft 22 in the housing inner cylinder 25. A coolant passage 27 is provided between the housing outer cylinder 26 and the housing inner cylinder 25 to prevent an excessive temperature rise of the device during operation.

  A tool or the like is attached to the front side (left side in the drawing) of the spindle 22 and a drive source such as a motor is connected to the rear side (right side in the drawing) of the spindle 22 via a rotation transmission mechanism. The spindle device 21 can be applied to various machine tools such as, for example, a machining center, a lathe, a milling machine, and a grinding machine.

  The configuration of the spindle device 21 is not limited to this, and a configuration in which a motor consisting of a stator and a rotor is directly incorporated into the main shaft in the device, a configuration incorporating a so-called built-in motor may be adopted. With this configuration, higher speed rotation is possible.

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

Raw materials used in the examples and comparative examples are collectively shown below.
(1) Resin material
Polyamide resin A: A resin using terephthalic acid and 1,10-decanediamine as main raw materials (Unitika XecoT XN500)
Polyamide 66 resin: Toray Industries Amilan CM 3001
Polyamide 46 resin: Stanyl TW300 manufactured by DSM
Polyamide 9T resin: Kuraray Genesta N1000
(2) Fibrous Reinforcement Glass Fiber: JAJA Fiber Glass 03JAFT692 (average fiber diameter 10 μm, average fiber length 3 mm)
Carbon fiber: HNA-C6 (average fiber diameter 7 μm, average fiber length 6 mm) manufactured by Toho Tenax Co., Ltd.

  Examples 1 to 6 and Comparative Examples 1 to 3 Using the resin composition in which the raw materials were blended in the proportions shown in Table 1, cages of Examples and Comparative Examples were produced, and various tests were carried out. A twin-screw extruder was used for the production of the resin composition. Glass fiber and carbon fiber were supplied using a metering side feeder to prevent breakage, and extruded and granulated. The obtained pellet for molding was molded by an in-line screw injection molding machine to obtain a desired holder shape (outer diameter 93 mm, inner diameter 88 mm, width 13 mm). The shape of the cage was a machined cage shown in FIG. After molding, the humidity control treatment was carried out in an atmosphere of 80 ° C. and 95% relative humidity, and each test was carried out on those which were allowed to absorb water. From the mass before and after humidity control of the obtained cage, the water absorption was measured by the following formula. The results are shown in Table 1.

[Calculation formula of water absorption rate] Water absorption rate (mass%) = (mass after humidity adjustment−mass before humidity adjustment) × 100 / mass before humidity adjustment

[Bearing temperature test]
Each of the produced cages was incorporated into angular contact ball bearings. The guide system of the cage was the outer ring guide system. Angular contact ball bearings are assembled with a constant pressure preload to form a spindle unit with a built-in motor. The lubrication method for bearings was air oil lubrication. Rotating the spindle by driving the built-in motor in the apparatus was carried out bearing temperature tests sequentially increasing the rotation speed to dm · n value 300 × 10 ^4. The test was stopped when the cage melted due to the temperature rise inside the bearing, and the dm · n value at that time was recorded. In addition, the case where it did not fuse | melt even if dm * n value 300 * 10 ⁴ was made into "none." The results are shown in Table 1.

As shown in Table 1, Comparative Example 1 (polyamide 66) in dm · n value 180 × 10 ^4, in Comparative Example 2 (polyamide 46) dm · n value 200 × 10 ^4, Comparative Example 3 (polyamide 9T) In each of the first to sixth embodiments, although the dm · n value 288 × 10 ⁴ melts the cage, in Examples 1 to 6, even if the rotation speed is increased to the dm · n value 300 × 10 ^{4, the} cage does not melt. It could be confirmed that

  From the above results, the rolling bearing of the present invention is stabilized without being seized even under high-speed rotation conditions by using a cage made of a predetermined resin composition and lubricating by oil mist lubrication or air oil lubrication. Turned out to be rotatable.

The rolling bearing of the present invention can be widely used as various rolling bearings because seizing and breakage do not occur even under high speed conditions such that dm · n value is 100 × 10 ⁴ or more. In particular, it is suitable as a rolling bearing of a spindle device for a machine tool spindle.

DESCRIPTION OF SYMBOLS 1 angular contact ball bearing 2 inner ring 3 outer ring 4 ball 5 cage 6 pocket 7 nozzle member 8 inner ring spacer 9 nozzle hole 10 inlet hole 11 housing 12 lubricating oil supply path 21 spindle device 22 main shaft 22 inner ring spacer 24 outer ring spacer 25 Housing inner cylinder 26 Housing outer cylinder 27 Coolant passage

Claims (6)

A rolling bearing comprising an inner ring and an outer ring, a plurality of rolling elements interposed between the inner and outer rings, and a cage for holding the rolling elements,
The rolling bearing is a rolling bearing used at high speed rotation of dm · n value 100 × 10 ⁴ or more, and lubricated by air oil lubrication or oil mist lubrication,
The cage is formed by injection molding a resin composition, and the resin composition comprises a polyamide resin consisting of a dicarboxylic acid component and a diamine component as a base resin, and a fibrous reinforcing material blended therein. The dicarboxylic acid component is mainly composed of terephthalic acid, the diamine component is mainly composed of 1,10-decanediamine, and the glass fiber is added to the entire resin composition as the fibrous reinforcing material. A rolling bearing comprising: 50% by mass or 10% to 35% by mass of carbon fibers.   The rolling bearing according to claim 1, wherein the polyamide resin has a melting point of 310 ° C. or more.   The rolling bearing according to claim 1 or 2, wherein the cage is an inner ring guide system or an outer ring guide system.   The rolling bearing according to any one of claims 1 to 3, wherein the rolling bearing is used in a spindle device. It said rolling bearing, according to any one of the preceding claims, characterized in that up to dm · n value 300 × 10 ⁴ is rotatable bearing to claim 4 rolling bearing.   A rolling bearing according to any one of claims 1 to 5, and a nozzle member for discharging lubricating oil of air oil or oil mist toward the raceway surface of the inner ring of the rolling bearing. Lubrication structure of rolling bearings.

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