JP2007057011A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing which improves mechanical strength and durability of a synthetic resin cage, has high reliability, and sufficiently endures even in high-speed applications. <P>SOLUTION: In this rolling bearing comprising an outer ring 11 having an outer ring raceway surface 11a on its inner peripheral face, an inner ring 12 having an inner ring raceway surface 12a on its outer peripheral face, a plurality of rolling elements 13 rollably disposed between the outer ring raceway surface 11a and the inner ring raceway surface 12a, and the synthetic resin cage 14 retaining the rolling elements 13 at equal intervals in the circumferential direction, the synthetic resin cage 14 is composed of a synthetic resin including glass fiber of average diameter of 2-4 μm by 20-50 mass%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rolling bearing including a synthetic resin cage, and more particularly to a rolling bearing suitable for high-speed rotation applications.

  Conventionally, a synthetic resin cage for a rolling bearing uses a glass fiber reinforced synthetic resin in which a glass fiber is blended as a reinforcing material in a polyamide resin such as nylon 66 or nylon 46 or a polyphenylene sulfide resin (for example, patents). See references 1 and 2.)

Japanese Patent No. 3001288 JP 2005-140168 A

  By the way, with the recent increase in the speed and performance of equipment, there is a strong demand for rolling bearings to rotate at high speed. Especially, in the case of needle roller bearings, the priority is given to the load capacity of the bearings. Since it is necessary to arrange as many as possible and to make the roller length as long as possible, as shown in FIG. 8, the column portion 7 a of the synthetic resin cage 7 becomes elongated and thin. For this reason, such a synthetic resin cage 7 is not sufficiently durable against repeated stress due to use, and stress tends to concentrate particularly on the corners of the corners of the pockets 7b in which the needle rollers are stored. Therefore, there has been a demand for improvement in durability of the synthetic resin cage for application to high-speed rotation.

  In addition, the strength of the synthetic resin cage can be increased by increasing the glass fiber content, but the glass fiber content is generally limited to about 50% by mass of the total cage due to moldability and shape retention. It is said that there is no room for further enhancement by the glass fiber content.

  The present invention has been made to eliminate such inconveniences, and its purpose is to improve the mechanical strength and durability of the synthetic resin cage, which is highly reliable for high-speed rotation applications. Another object is to provide a rolling bearing that can sufficiently withstand.

The above object of the present invention can be achieved by the following constitution.
(1) An outer ring having an outer ring raceway surface on an inner peripheral surface, an inner ring having an inner ring raceway surface on an outer peripheral surface, a plurality of rolling elements provided in a freely rolling manner between the outer ring raceway surface and the inner ring raceway surface, A synthetic resin cage that holds the moving body at equal intervals in the circumferential direction, and the synthetic resin cage contains 20 to 50% by mass of glass fiber having an average diameter of 2 to 4 μm. A rolling bearing made of resin.
(2) The rolling bearing according to (1), wherein the glass fiber is surface-treated with a surface treatment agent containing at least one of a binder, a coupling agent, a lubricant, and an antistatic agent.

  According to the present invention, since the synthetic resin cage is made of a synthetic resin containing 20 to 50% by mass of glass fibers having an average diameter of 2 to 4 μm, the mechanical strength and durability of the synthetic resin cage are improved. Therefore, it is possible to provide a rolling bearing that is highly reliable and can sufficiently withstand high-speed rotation applications.

Hereinafter, an embodiment of a rolling bearing according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view for explaining a rolling bearing according to the present invention, and FIG. 2 is a perspective view for explaining a cage incorporated in the rolling bearing shown in FIG.

  As shown in FIG. 1, the rolling bearing 10 of this embodiment includes an outer ring 11 having an outer ring raceway surface 11a on an inner peripheral surface, an inner ring 12 having an inner ring raceway surface 12a on an outer peripheral surface, an outer ring raceway surface 11a and the inner ring. A plurality of rolling elements 13 interposed between the raceway surface 12 a and the raceway surface 12 a, a synthetic resin cage 14 that holds the rolling elements 13 at substantially equal intervals in the circumferential direction, and an outer ring 11 and an inner ring 12. And a seal member 15 for sealing an annular space formed therebetween. In this embodiment, the seal member 15 is a metal inner ring non-contact type in which a cold-rolled steel sheet is galvanized or the like, but a rubber seal type (inner ring Contact, inner ring contact).

  As shown in FIG. 2, the synthetic resin cage 14 is a crown type cage, and is provided on an annular main portion 20 and one surface of the main portion 20 and is arranged at equal intervals in the circumferential direction. A plurality of elastic pieces 21 are provided, and a plurality of pockets 22 are formed between the pair of elastic pieces 21 that are spaced apart from each other so as to hold the rolling element 13 in a freely rollable manner.

  The synthetic resin cage 14 is made of a synthetic resin (glass fiber reinforced synthetic resin) containing 20 to 50% by mass of glass fibers having an average diameter of 2 to 4 μm. Polyphenylene sulfide resin, aromatic polyamide resin, polyamide 46, polyamide 66 and the like can be preferably used. Polyphenylene sulfide resin has low water absorption, excellent heat resistance, and good moldability. Therefore, it is excellent in dimensional stability with low water absorption and can be used at high temperatures of 150 to 180 ° C by injection molding. It can be formed at low cost. The aromatic polyamide resin has a high melting point and high strength, and can be used at a high temperature of 120 ° C to 140 ° C. On the other hand, polyamide 46 is also preferable because it has heat resistance of 120 ° C. to 140 ° C., the resin itself has high impact strength and fatigue resistance, and is improved in reliability against breakage of the cage. Furthermore, although the polyamide 66 has a heat resistance of 100 to 120 ° C., it has a good balance of impact strength, fatigue resistance, and the like, and is most suitable depending on the use environment because of a low material cost. Here, the glass fiber having an average diameter of 2 μm is a glass fiber falling within the range of 1 to 3 μm in diameter, and the glass fiber having an average diameter of 4 μm is a glass fiber falling within the range of 3 to 5 μm in diameter. That is.

  Further, the molecular weight of the synthetic resin of the synthetic resin cage 14 is preferably within a range where the glass fiber can be injection-molded, specifically 13,000 to 30000 in terms of number average molecular weight, more preferably impact strength and the like. In consideration of the mechanical strength and moldability, the number average molecular weight is in the range of 18000 to 26000. In addition, when a number average molecular weight is less than 13000, molecular weight is too low, mechanical strength becomes low, and practicality becomes low. On the other hand, when the number average molecular weight exceeds 30000, when 20 to 50% by mass of glass fiber is contained as in the present embodiment, the melt viscosity becomes too high, and the cage is manufactured by injection molding with high accuracy. It becomes difficult and is not preferable.

  Moreover, as content of the glass fiber of the cage | basket 14 made from a synthetic resin, 20-50 mass% of the whole is preferable, More preferably, it is the range of 25-35 mass%. In addition, when content of glass fiber is less than 20 mass%, there is little improvement effect of mechanical strength and a dimensional change, and is unpreferable. On the other hand, when the glass fiber content exceeds 50% by mass, the moldability deteriorates and the toughness decreases conversely, and it is damaged when forcibly removing from the mold during molding or when the rolling element is inserted. There is fear and it is not preferable.

  Moreover, as an average fiber length of the glass fiber of the cage 14 made of synthetic resin, 100-900 micrometers is preferable, More preferably, it is the range of 300-600 micrometers. In addition, when average fiber length is less than 100 micrometers, it is too short and there are few reinforcement effects and a dimensional suppression effect, and is unpreferable. On the other hand, when the average fiber length exceeds 900 μm, although the dimensional suppression effect and the reinforcing effect are improved, it is preferable that the fiber is broken in the resin part molding step or the molding accuracy is deteriorated due to the decrease in orientation. Absent.

  Furthermore, in this embodiment, the glass fiber of the synthetic resin cage 14 is subjected to a surface treatment with a surface treatment agent immediately after spinning in consideration of adhesiveness with the resin. Specifically, it is treated with a resin-based emulsion called a binding agent, a coupling agent for binding both glass and resin, a surface treatment agent to which various components such as a lubricant and an antistatic agent are added. ing.

  As the binding agent, epoxy resin, urethane resin, polyester resin, vinyl acetate resin, acrylic resin, and the like can be used. The effect is recognized when any binding agent is used, but the effect is particularly favorable when an epoxy resin is used. When the base resin is a polyamide-based resin, the glass fiber binder is a copolymer containing maleic anhydride as one component (specifically, a copolymer of maleic anhydride and vinyl ester, maleic anhydride and A copolymer with vinyl ether or a copolymer of maleic anhydride and acrylic acid is particularly suitable. The reason is that the combination of a binder and a coupling agent is a combination of a copolymer containing maleic anhydride as a component and an aminosilane-based coupling agent, thereby providing a strong glass fiber-coupling agent-binding agent. This is because a four-layer structure of a polyamide resin matrix can be constructed.

  As coupling agents, there are silane-based, chromium-based, titanium-based and the like, but at present, the use of silane-based coupling agents occupies the majority. The silane coupling agent has a silanol group that binds to the glass fiber at one end and an organic functional group that can bind to the resin matrix or the binding agent at the other end. In the case of a fiber reinforced resin using a thermoplastic resin as a matrix, the binding agent remains on the glass fiber surface without melting and diffusing in the resin matrix. For this reason, as a coupling agent for a fiber reinforced thermoplastic resin, an aminosilane-based coupling agent (specifically, N-β- (aminoethyl) γ-aminopropyltrimethoxysilane) excellent in adhesion to a binder is used. N-β- (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, or the like) is preferable.

  Moreover, in the synthetic resin composition (synthetic resin cage 14) of this embodiment, in addition to glass fibers, carbon fibers, aramid fibers, silicon carbide fibers, wollastonite, and zinc oxide are used as fibrous fillers. Whisker such as whisker, potassium titanate whisker and aluminum borate whisker may be added. In addition, you may use the above-mentioned fibrous filler individually or in combination of 2 or more types. Further, non-fibrous fillers such as zeolite, kaolin, mica, clay, talc, alumina and silica may be added. In addition, a minimal amount of a compounding agent such as a pigment, a dye, an antistatic agent, and a solid lubricant such as a fluororesin may be added as necessary. In order to prevent deterioration due to heat during molding and use, an iodide heat stabilizer and an amine antioxidant may be added alone or in combination as additives. Further, a rubber-like substance such as ethylene propylene non-conjugated diene rubber (EPDM) that improves impact resistance may be added separately.

  In addition, there is no restriction | limiting in the adjustment method of the glass fiber reinforced synthetic resin of this embodiment, and the shaping | molding method to a holder | retainer, Each can follow a conventional method. As a molding method, injection molding is preferable in consideration of productivity.

  Below, the reason for the improvement of the physical property of a synthetic resin composition by refinement | miniaturization of a glass fiber diameter and use of the surface treating agent containing a specific binding agent is demonstrated.

  As the glass fibers contained in the synthetic resin cage 14 of the present embodiment, those having an average diameter in the range of 2 to 4 μm are used, and such glass fibers having an average diameter of 2 to 4 μm are conventionally used. If the weight content is the same as that of the glass fiber having an average diameter of 10 to 13 μm, the actual number will increase. And since the total surface area of the glass fiber which is a reinforcement material increases dramatically in connection with this, the reinforcement efficiency will improve rather than the case where the glass fiber of the conventional average diameter is used.

  Moreover, the dimensional change suppression effect by the glass fiber of the synthetic resin cage 14 of the present embodiment is greater than that of the glass fiber having an average diameter of 10 to 13 μm containing the same weight. Such a property is also caused by the fact that the number of the substantial number increases and the degree of the restraining action of the resin molecular chain by the glass fiber increases in the case of the same weight content.

  Furthermore, in the synthetic resin cage 14 of the present embodiment, not only the improvement of the dimensional change suppression effect described above, but also the case of containing the glass fiber having an average diameter of 10 to 13 μm in the case of the same weight content. Therefore, it can cope with higher speed. This is because it is possible to withstand a greater load (repeated stress accompanying use) by an increase in the number of glass fibers.

  Therefore, according to the rolling bearing 10 of the present embodiment, the synthetic resin cage 14 is made of a synthetic resin containing 20 to 50% by mass of glass fibers having an average diameter of 2 to 4 μm. It is possible to provide a rolling bearing that can improve mechanical strength and durability, has high reliability, and can sufficiently withstand high-speed rotation applications.

  Further, according to the rolling bearing 10 of the present embodiment, the glass fiber is subjected to a surface treatment with a surface treatment agent containing at least one of a binding agent, a coupling agent, a lubricant, and an antistatic agent. And the synthetic resin can be improved in adhesiveness (bonding property). Thereby, since the reinforcement efficiency of glass fiber can be improved, the mechanical strength and durability of the synthetic resin cage 14 can be further improved.

Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, and the like can be made as appropriate.
For example, in this embodiment, although the case where this invention was applied to the deep groove ball bearing was illustrated, it is not limited to this, The holder | retainer (refer FIG. 4, 5) of an angular ball bearing (refer FIG. 3), Even if the present invention is applied to a cage for a tapered roller bearing (see FIG. 6), a cage for a cylindrical roller bearing (see FIG. 7), a cage for a needle roller bearing (see FIG. 8), etc. Good.

  Below, the test performed in order to investigate the effect which the difference in a fiber diameter has on the physical property of a synthetic resin composition about the resin matrix of nylon 66 and nylon 46 is demonstrated.

  In this test, nylon 66 (UBE Nylon 2020U manufactured by Ube Industries Co., Ltd.) and nylon 46 (DJEP Stanyl TW341) have two different average diameters (3 μm (Examples 1 and 2), 13 μm (Comparative Example). A total of four types of glass fiber reinforced nylon containing 30% by mass of the glass fibers of 1, 2)) are used.

  In this test, the tensile test, Izod impact test, heat resistance, and grease resistance evaluation of the above four types of glass fiber reinforced nylon are carried out. The tensile strength conformed to JIS K7113, and the Izod impact strength conformed to JIS K7110. For heat resistance, the tensile strength was measured after holding the test piece at 160 ° C. for 1000 hours, and a relative value was obtained with an initial value of 100. The grease resistance was obtained by immersing the test piece in a poly α-olefin oil-urea grease at 140 ° C. for 1000 hours and then measuring the tensile strength to obtain a relative value with an initial value of 100. The results are shown in Table 1.

  As is clear from Table 1, in both nylon 66 and nylon 46, the mechanical diameter (tensile strength, Izod impact strength), heat resistance, and grease resistance are improved by changing the average diameter of the glass fiber from 13 μm to 3 μm. Since everything was improved, it was found that Examples 1 and 2 had excellent mechanical strength and durability. Accordingly, when the first and second embodiments are used for the synthetic resin cage 14 of the rolling bearing 10, the durability of the synthetic resin cage 14 is improved, so that the rolling bearing 10 can be applied to high-speed rotation applications. I understand.

It is sectional drawing for demonstrating the rolling bearing which concerns on this invention. It is a perspective view for demonstrating the holder | retainer integrated in the rolling bearing shown in FIG. It is sectional drawing which shows an angular contact ball bearing. It is a perspective view which shows an example of the holder | retainer integrated in the angular ball bearing shown in FIG. It is a perspective view which shows the other example of the holder | retainer integrated in the angular ball bearing shown in FIG. It is a perspective view which shows the holder | retainer integrated in a tapered roller bearing. It is a perspective view which shows the holder | retainer integrated in a cylindrical roller bearing. It is a figure which shows the holder | retainer integrated in a needle roller bearing, (a) is the figure seen from the axial direction, (b) is the figure seen from radial direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Rolling bearing 11 Outer ring 11a Outer ring raceway surface 12 Inner ring 12a Inner ring raceway surface 13 Rolling element 14 Synthetic resin cage 15 Seal member 20 Main part 21 Elastic piece 22 Pocket

Claims (2)

An outer ring having an outer ring raceway surface on an inner peripheral surface, an inner ring having an inner ring raceway surface on an outer peripheral surface, a plurality of rolling elements provided rotatably between the outer ring raceway surface and the inner ring raceway surface, and the rolling A rolling bearing comprising a synthetic resin cage that holds the moving body at equal intervals in the circumferential direction,
The synthetic resin cage is made of a synthetic resin containing 20 to 50% by mass of glass fibers having an average diameter of 2 to 4 μm.   The rolling bearing according to claim 1, wherein the glass fiber is surface-treated with a surface treatment agent containing at least one of a binder, a coupling agent, a lubricant, and an antistatic agent.

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