JP2000120697A - Roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably prolong the lifetime of lubrication by forming a rolling body of a roller bearing hollow, and filling the hollow part with the lubricant. SOLUTION: A cylinder roller 1 is formed with a hollow part 1d passing through both end surfaces 1b, 1c along the axis C in parallel with a rolling surface 1a, and this hollow part 1d is filled with the lubricant. As a hollow rolling body, a cylindrical, a conical and a spherical roller can be used, and volume of the hollow part 1d is set within a range capable of obtaining the necessary strength, and as a forming method, any method of grinding and casting with a header can be used. About the lubricant, as a grease, a paraffin or a naphthenic hydrocarbon is used, and as a solid lubricant, polytetraphloroethylene and graphite is used, and as a lubricant included polymer member, the mixture obtained by mixing any one of paraffin and naphthenic hydrocarbon as the lubricant in the polymer of polyethylene and polypropylene can be used. With this structure and composition, lubricant holding quantity is increased, and lifetime of the lubrication can be remarkably prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller bearing, and more particularly to a roller bearing having improved lubrication life.

[0002]

2. Description of the Related Art In general, a roller bearing is used in a part of a variety of mechanical devices for supporting a rotating shaft to which a large load is applied. Conventional roller bearings have been lubricated by feeding lubricating oil, which is a fluid, into the bearing, immersing the entire bearing in the lubricating oil, or sealing grease inside the bearing. In such a lubrication method, a lubricant is filled in a bearing space obtained by removing the volumes of the rolling elements and the cage from the inner volume formed by the inner ring and the outer ring. Further, as another lubrication method, for example, Japanese Patent Application Laid-Open No. 7-145818,
A roller bearing consisting of an outer ring, an inner ring, and a plurality of rollers interposed between the outer ring and the inner ring.The technology is characterized in that a recess is provided in the outer ring, the inner ring or the roller, and the recess is filled with a lubricant-containing polymer member. It has been disclosed.

[0003]

However, according to the above-described lubrication method of filling the bearing space with a lubricant, the injected or sealed lubricating oil or grease flows out of the bearing together with use, and the cylindrical surface of the roller is used. Gaps between the inner and outer rings,
There has been a problem that lubricating oil and grease are not retained in portions requiring sufficient lubrication, such as clearance grooves provided in the inner ring and the outer ring. In particular, since the volume of the bearing space in the roller bearing is small, the amount of lubricating oil or grease injected or sealed is small, and there is a possibility of leakage to the outside of the bearing. Further, in the technique disclosed in Japanese Patent Application Laid-Open No. Hei 7-145818, the inner volume of the recess provided in the outer ring, the inner ring, and the rollers is not so large, and the amount of retained lubricant cannot be said to be sufficient. Since the rollers and the rollers are made of metal, the adhesion to the lubricant-containing polymer member is low, and the lubricant-containing polymer member may fall off from the recess. As described above, an object of the present invention is to provide a roller bearing having an improved lubrication life over a conventional roller bearing.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a roller bearing having a plurality of rolling elements rotatably held between an inner ring and an outer ring. This can be achieved by a roller bearing characterized in that the hollow portion is filled with a lubricant. The roller bearing of the present invention uses a rolling element having a hollow portion and fills it with a lubricant, so that the amount of retained lubricant is larger than before. As a result, the bearing life can be greatly extended as compared with the conventional roller bearing.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings. INDUSTRIAL APPLICABILITY The present invention can be applied to cylindrical, tapered, and spherical roller bearings as long as it is a roller bearing capable of producing a hollow rolling element. As the bearing, cylindrical roller bearings, tapered roller bearings, and spherical roller bearings The present invention includes needle roller bearings, thrust roller bearings, thrust tapered roller bearings, thrust needle roller bearings, cross roller bearings, and the like. The following is an example of hollow rollers.

For example, FIG. 1 is a cross-sectional view showing a hollow cylindrical roller 1, in which a hollow portion 1d penetrating both end surfaces 1b and 1c along an axis C parallel to a rolling surface 1a is formed.
This hollow portion 1d is filled with a lubricant. FIG. 2 is a cross-sectional view showing the hollow tapered roller 2. A hollow portion 2d penetrating both end surfaces 2b and 2c along the axis C is formed, and the hollow portion 2d is filled with a lubricant. Is done. As shown in the figure, the hollow portion 2d is also effective when the cross-sectional area gradually decreases from the small-diameter end surface 2b to the large-diameter end surface 2c. Further, as shown in FIG. 3, the hollow cylindrical roller 3 may be provided with an anchor portion 3e protruding toward the hollow portion 3d. Similarly, as shown in FIG. 4, an anchor portion 4e protruding toward the hollow portion 4d of the hollow tapered roller 4 may be provided. Such an anchor part 3
By providing e and 4e, it is possible to increase the mechanical strength of the rollers and to prevent the lubricant-containing polymer member from falling off, especially when the lubricant-containing polymer member is used as the lubricant.

[0007] The volume of the hollow portion is not particularly limited, and is appropriately set within a range in which the required strength as a roller is obtained. The method of forming the hollow portion may be either grinding or forging with a header, and there is no need for high-precision machining unless the shaft is affected.

[0008] The hollow portion is filled with a lubricant such as grease, a solid lubricant, or a polymer member containing a lubricant. These lubricants are not particularly limited,
Conventionally, those used for lubricating roller bearings can be appropriately selected and used. The filling amount is determined according to the volume of the internal space. Hereinafter, suitable lubricants for the present invention will be exemplified. As the grease, for example, paraffinic hydrocarbon oil such as poly α-olefin oil, naphthenic hydrocarbon oil, mineral oil, ether oil such as dialkyldiphenyl ether oil, phthalic acid ester, ester oil such as trimellitic acid ester Or the like as a base oil, to which a thickener such as a metallic soap or a urea compound is blended.

As the solid lubricant, for example, polytetrafluoroethylene (PTFE), MoS ₂ , graphite, h-BN, fluorinated graphite and the like can be used.

The lubricant-containing polymer member is made of polyethylene,
To a polymer selected from the group of poly-α-olefin polymers such as polypropylene, polybutylene, and polymethylpentene, as a lubricant, paraffin-based hydrocarbon oil such as poly-α-olefin oil, naphthenic hydrocarbon oil, mineral oil, dialkyl diphenyl ether A mixture obtained by mixing any one of ether oils such as oil, ester oils such as phthalic acid ester and trimellitic acid ester can be used. The polymer groups have the same molecular structure but different average molecular weights, ranging from 1 × 10 ^{3 to} 5 × 10 ⁶ . Among them, the average molecular weight is 1 × 10 ³ -1 × 1
0 and having a relatively low molecular weight of ^6, 1 × 10 ^{6 ~5} ×
An ultra-high molecular weight of 10 ⁶ is used alone or as a mixture if necessary. Further, if necessary, an antioxidant, a rust inhibitor, an antiwear agent, an antifoaming agent,
Various additives such as extreme pressure agents may be added.

Further, particularly when heat resistance is required,
A lubricant-containing polymer member based on a thermosetting resin instead of the poly-α-olefin polymer is preferred. Examples of the thermosetting resin that can be used in the present invention include diallyl phthalate-based resins, phenol-based resins, and polycarbodiimide-based resins. More specifically, the diallyl phthalate-based resin is a homopolymer of a diallyl phthalate, diallyl isophthalate, diallyl terephthalate monomer or prepolymer, or two or more monomers or prepolymers of these. Copolymers and mixtures with these homopolymers are possible. Since the diallyl phthalate resin cannot be cured by heating as it is, it is usually necessary to use a peroxide as a curing agent (polymerization initiator). As the peroxide, benzoyl peroxide, m
-Toluoyl peroxide, t-butyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, 2,5-dimethyl-2,
5-di (benzosylperoxy) hexane, dicumyl peroxide and the like can be used. At the time of polymerization, these curing agents are used in an amount of about several wt%,
About t% is added.

The phenolic resins usable in the present invention are pure phenolic resins of resol type, pure phenolic resins of novolak type and various modified phenolic resins. Examples of the modified phenolic resin include cashew-modified phenolic resin (novolak type, resol type) and oil-modified phenolic resin (novolak type)
Etc. can be used. The novolak type phenol resin does not cure as it is, and it is necessary to add a hexamine or resol type phenol resin as a curing agent. On the other hand, a resol type phenol resin is cured by heating without addition. In addition, an oil-modified phenol resin has a weak ability to hold a lubricating oil at the time of curing and cannot be used alone. Therefore, it is necessary to use a mixture of other phenol resins. Further, the polycarbimide resin that can be used in the present invention is cured by heating without addition.

When these thermosetting resins are used in a lubricant-containing polymer member, the lubricating oil to be combined must be compatible with the thermosetting resin, for example, diisodecyl phthalate, di-2-ethylhexyl phthalate, diisodecyl adipate. And ester oils such as di-2-ethylhexyl sebacate and tri-2-ethylhexyl trimellitate, polyol ester oils, and phenyl ether oils such as octadecyl phenyl ether, tetraphenyl ether and pentaphenyl ether.

In the present invention, instead of the lubricating oil, a grease using the lubricating oil as a base oil can be mixed with a polymer. In this case, a suitable amount of a well-known metal soap such as lithium soap is added to the lubricating oil so as to be harmonized. still,
When the thermosetting resin is a polymer, as described above,
The type of lubricating oil that becomes compatible differs depending on the type, or even if the lubricating oil is uniformly dissolved before curing, the resin and lubricating oil or grease may separate after curing. You need to be careful about the alignment. Since diallyl phthalate is compatible with all of the lubricating oil or grease, a good lubricating composition can be obtained in any combination.However, when a phenolic resin or a carbodiimide resin is used, Combinations are restricted. For example, it is preferable to use polyphenyl ether oil for pure phenol resin, diester oil and polyol ester oil for cashew-modified phenol resin, and further use polyphenyl ether oil and alkyl polyphenyl ether oil for oil-modified phenol resin. .

Further, the following fillers may be added for the purpose of reinforcing the mechanical strength of the lubricant-containing polymer member and improving the formability. For example, minerals such as calcium carbonate, talc silica, clay, and mica; inorganic whiskers such as potassium titanate whiskers and aluminum borate whiskers; and inorganic fibers such as glass fibers, asbestos, quartz wool, and metal fibers; In the case of a braided shape or an organic compound, carbon black, graphite powder, carbon fiber, aramid fiber, polyester fiber, or various thermosetting resins such as polyimide and polybenzimidazole can be added. Further, for the purpose of improving the thermal conductivity of the lubricating composition, carbon fibers, metal fibers, graphite powder, metal powder, ZnO powder and the like may be added. Further, in the lubricant-containing polymer member,
Acrylic resins such as polypropylene, polystyrene, polyethylene, polyurethane, and polymethacrylic ester, which are high oil-absorbing polymers, or polynorbornene may be used alone or in combination of two or more. Also,
Polynorbornene may be used as the base resin.

The method of filling the hollow roller with the lubricant-containing polymer member can be performed by an injection molding machine in addition to a method using an injection means such as a syringe. When the polymer used is a thermoplastic resin, the polymer is heated to a temperature equal to or higher than the melting point of the thermoplastic resin, and then cooled and solidified. On the other hand, when the polymer to be used is a thermosetting resin, it is cured by heating to a curing temperature.

The hollow roller filled with the lubricant prepared as described above is incorporated between the inner ring and the outer ring in the same manner as the other rollers. It can be arbitrarily selected depending on conditions and the like. When the present invention is applied to a plurality of rollers, it is desirable to dispose them as symmetrically as possible in consideration of the balance during rotation of the bearing. Since the roller bearing of the present invention is filled with a lubricant in the hollow portion of the roller, it retains a larger amount of lubricant than the conventional roller bearing. Since the lubricating oil is supplied to the rolling surface and the raceway surface of the bearing, the lubrication of the bearing can be maintained for a long time.

Hereinafter, the present invention will be further described with reference to experimental examples. (First experiment) Inner diameter φ25 mm, outer diameter φ62 mm, width 17
mm, a cylindrical roller bearing with an inner ring flange having a rolling element diameter of 9 mm was used as a test piece, and 13 of them were coated with mineral oil-based grease in the hollow cylindrical roller 1 (volume ratio of the hollow portion 1d: 25%) shown in FIG. A bearing was prepared in place of the filled one and used as a product of the present invention. Further, a specimen itself without using the hollow cylindrical roller 1 was used as a comparative example. The total amount of grease is 2.8 g for both bearings. And for both bearings,
With the outer lid fitted on the bearing end face, the rotation speed is 10,000 rpm.
m, a radial load of 2 kN, and a bearing temperature of 110 ° C., an endurance test was performed. The results are shown in Table 1, and it can be seen that the bearing life of the product of the present invention is greatly extended.

[0019]

[Table 1]

A similar experiment was conducted on a bearing incorporating the hollow tapered roller 2 shown in FIG. 2, and a durability time equivalent to that of the bearing incorporating the hollow cylindrical roller 1 was obtained.

(Second experiment) Polyethylene obtained by mixing low molecular weight polyethylene [Mitsubishi Yuka Co., Ltd .: PZ50U] and ultra high molecular weight polyethylene [Mitsui Petrochemical Co., Ltd .: XM220] at a ratio of 1: 1. In 30 parts of powder, paraffinic mineral oil [Nippon Oil Co., Ltd .: FBK Oil RO100] 7
0 parts were mixed and uniformly mixed using a kneader to prepare a lubricant-containing polymer member. The lubricant-containing polymer member is a paste-like substance, which is injected into the hollow portion 3d of the hollow cylindrical roller 3 shown in FIG. 3 and kept at 150 ° C., which is a temperature not lower than the melting point of polyethylene, for 20 minutes. After cooling, a hollow cylindrical roller 3 filled with a lubricant-containing polymer member was obtained. Thirteen of these hollow cylindrical rollers 3 were assembled in the test sample of the first experiment to produce a bearing, which was used as a product of the present invention. In addition, a specimen itself without using the hollow cylindrical roller 3 was used as a comparative example. Then, for both bearings, 3000 rpm at room temperature
m and the lubricity was examined. At that time, an axial load of 4 kN was applied, and 200 cc of turbine oil per minute was supplied to the bearing, and the oil supply was stopped 20 minutes after the start. The time from the stop of refueling to the seizure of the bearing was compared. The results are shown in Table 2, and it can be seen that the bearing life of the product of the present invention is greatly extended.

[0022]

[Table 2]

A similar experiment was conducted on a bearing incorporating the hollow tapered roller 4 shown in FIG. 4, and the same lubricity as that of the bearing incorporating the hollow cylindrical roller 2 was obtained.

[0024]

As described above, the roller bearing of the present invention uses a rolling element having a hollow portion and is filled with a lubricant, so that the amount of retained lubricant is larger than in the prior art. As a result, the bearing life can be greatly extended as compared with the conventional roller bearing.

[Brief description of the drawings]

FIG. 1 is a sectional view of a hollow cylindrical roller according to the present invention.

FIG. 2 is a sectional view of a hollow tapered roller according to the present invention.

FIG. 3 is a sectional view of a hollow cylindrical roller with an anchor according to the present invention.

FIG. 4 is a cross-sectional view of a hollow tapered roller with an anchor according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow cylindrical roller 1d hollow part 2 hollow tapered roller 2d hollow part 3 hollow cylindrical roller 3d hollow part 3e anchor part 4 hollow tapered roller 4d hollow part 4e anchor part

Claims (1)

[Claims] 1. A roller bearing having a plurality of rolling elements rotatably held between an inner ring and an outer ring, wherein the rolling elements are hollow, and the hollow portion is filled with a lubricant. Roller bearing.