JP2000304057A - Lubricant including polymer filling cylindrical roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant including polymer filling cylindrical roller bearing of a low torque, by preventing the projection of a lubricant including polymer from the side end surfaces of an inner ring and an outer ring, owing to a temperature rise. SOLUTION: In this lubricant including polymer filling cylindrical roller bearing, a lubricant including polymer 5 is filled in an inner ring 2, an outer ring 3, a cylindrical roller, and in a space formed of the rings and the roller. The side end surfaces 7 of the lubricant including polymers 5 are arranged at the inner sides from side end surfaces 8 and 9 of the inner ring 2 and the outer ring 3, by providing the intervals larger than the curvature radius (r) of the circular arc form angle parts 10 and 11 formed on the outer peripheral surface of the inner ring 2 and on the inner peripheral surface of the outer ring 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant-filled polymer-filled cylindrical roller bearing in which a space formed by an inner ring, an outer ring and rolling elements is filled with a lubricant-containing polymer.

[0002]

2. Description of the Related Art Conventionally, a space formed by an inner ring, an outer ring and a rolling element of a cylindrical roller bearing is filled with lubricating oil, grease or the like in order to impart lubricity. However, since these lubricating oils and greases are liquid or semi-solid substances, they may scatter during use of cylindrical roller bearings,
There was a problem of fluidization.

In order to prevent the scattering and fluidization, a lubricant-filled polymer-filled cylindrical roller bearing has been developed in which a space formed by an inner ring, an outer ring and rolling elements is filled with a lubricant-containing polymer. This lubricant-containing polymer-filled cylindrical roller bearing has a structure in which the side end faces of the lubricant-containing polymer coincide with the side end faces of the inner ring and the outer ring, that is, they have a structure in which these are flush.

[0004]

However, when the temperature of the bearing is increased due to rotation, the lubricating polymer-filled cylindrical roller bearing having the above structure has a higher plastic expansion coefficient than the metal inner and outer rings. Since the coefficient of linear expansion of the lubricant-containing polymer made of the polymer is large, the lubricant-containing polymer may protrude from the side end surfaces of the inner ring and the outer ring, and a problem may occur.

The corners of the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring are usually chamfered in an arc shape, but the surface roughness is generally considerably rougher than the raceway surface of the bearing. It is. That is, when the lubricant-containing polymer comes into contact with the arc-shaped corners, resistance is generated, and there is a possibility that the bearing torque increases.

SUMMARY OF THE INVENTION It is an object of the present invention to solve such a conventional problem, and a low torque torque-preventing polymer in which a lubricant-containing polymer is prevented from protruding from side end surfaces of an inner ring and an outer ring due to a rise in temperature. An object of the present invention is to provide a lubricant-containing polymer-filled cylindrical roller bearing.

[0007]

In order to achieve this object, the present invention provides an inner ring and an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and the inner ring, the outer ring and the rolling elements. In a lubricant-containing polymer-filled cylindrical roller bearing formed by filling a lubricant-containing polymer into a space formed by:
The lubricant-containing polymer has a side end face arranged inside the side end faces of the inner ring and the outer ring, and a distance between the side end face of the lubricant-containing polymer and the side end faces of the inner ring and the outer ring is such that the inner ring The present invention provides a lubricant-filled polymer-filled cylindrical roller bearing having a radius of curvature larger than the radius of curvature of the arc-shaped corner formed on the outer peripheral surface and the inner peripheral surface of the outer ring.

The lubricant-containing polymer-filled cylindrical roller bearing having this structure does not protrude from the side end faces of the inner and outer rings even if the lubricant expands from the inner and outer rings due to a rise in temperature. Further, since the lubricant-containing polymer can be prevented from covering the arcuate corners formed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, lower torque can be achieved.

Examples of the lubricant-containing polymer usable in the present invention include synthetic resins selected from the group of polyolefin resins having basically the same chemical structure, such as polyethylene, polypropylene, polybutylene, and polymethylpentene. As a lubricant, a paraffinic hydrocarbon oil such as a poly-α-olefin oil, a naphthenic hydrocarbon oil, a mineral oil,
Ether oils, such as dialkyl diphenyl ether oils,
Raw materials prepared by mixing in the form of any one or a mixture of oils such as ester oils such as phthalic acid esters are plasticized by heating above the melting point of the resin, and then solidified by cooling, Various additives such as an antioxidant, a rust inhibitor, an antiwear agent, an antifoaming agent, and an extreme pressure agent may be added in advance to the lubricant.

The composition ratio of the lubricant-containing polymer is 10 to 50% by weight of the polyolefin resin and 90 to 50% by weight of the lubricant based on the total weight.

When the content of the polyolefin resin is less than 10% by weight, a certain level of hardness and strength cannot be obtained. For example, when a load is applied due to rotation of a bearing or the like,
It becomes difficult to maintain the initial shape, and there is a high possibility that problems such as detachment from the internal space of the bearing will occur.

The polyolefin resin is 50% by weight.
(I.e., when the amount of the lubricant is less than 50% by weight), the supply of the lubricant to the bearing is reduced, and the life of the bearing is shortened.

The synthetic resin group has the same basic structure but the same structure.
Have different average molecular weights, 700 to 5 × 10⁶Range of
It extends to the enclosure. That is, the average molecular weight is 700 to 1 ×
10 ⁴Wax (for example, polyethylene wax
And the average molecular weight is 1 × 10⁴~ 1
× 10⁶Relatively low molecular weight and average molecular weight
1 × 10⁶~ 5 × 10⁶With the ultra-high molecular weight
It is used alone or as a mixture if necessary. Relatively low
To a certain extent depending on the combination of
Lubricant containing mechanical strength, lubricant supply capacity, oil retention
A polymer is obtained. One of the relatively low molecular weight
Replace the parts with those classified as wax,
The difference in molecular weight between those classified as
The lubricating oil, and as a result
The lubricating properties of the lubricant-containing polymer are improved, and
Lubricants can be supplied. However, on the other hand, mechanical strength
Tends to decrease.

As the wax, besides a polyolefin resin such as polyethylene wax, a melting point of 100 to 1 is used.
Any hydrocarbon-based (for example, paraffin-based synthetic wax) having a temperature of 30 ° C. or higher can be used.

On the other hand, when a super-high molecular weight product is replaced with a lubricating oil, the difference in molecular weight between the ultra-high molecular weight product and the lubricating oil is large, so that the affinity with the lubricating oil is lowered, and as a result, the oil retaining property is reduced. In addition, the oozing of the lubricant from the lubricating oil-containing polymer is accelerated. Thereby, the time required to reach the amount of lubricant that can be supplied from the lubricant-containing polymer is shortened, and the life of the bearing is shortened. However, the mechanical strength is improved.

Considering the balance of moldability, mechanical strength, oil retention, and lubricant supply, the composition ratio of the lubricant-containing polymer is 0 to 5% by weight for waxes and relatively low molecular weight. 8 to 48%, ultra high molecular weight 2 to 48%
15% by weight, the sum of the three resin components is 10 to 50% by weight
(The balance is 90 to 50% by weight of a lubricant).

As one of the mechanical strengths, the hardness “HD _A ” of the lubricant-containing polymer of the present invention is preferably in the range of 65 to 85, more preferably in the range of 70 to 80. If the hardness “HD _A ” is less than 65, the bearing is weak in strength and may be damaged by rotation of the bearing. On the other hand, when the hardness “HD _A ” exceeds 85, the force for restraining the rollers (rolling elements) is large, thereby increasing the torque of the bearing or increasing the heat generated by the rotation of the bearing. Temperature may increase.

In order to improve the mechanical strength of the lubricant-containing polymer of the present invention, a thermoplastic resin and a thermosetting resin as described below may be added to the polyolefin resin.

As the thermoplastic resin, various resins such as polyamide, polycarbonate, polybutylene terephthalate, polyphenylene sulfide, polyether sulfone, polyether ether ketone, polyamide imide, polystyrene and ABS resin can be used.

These resins may be used alone or as a mixture.

Further, in order to disperse the polyolefin resin and other resins in a more uniform state, a suitable compatibilizer may be added as necessary.

Further, a filler may be added to improve the mechanical strength. As the filler, for example,
Calcium carbonate, magnesium carbonate, inorganic whiskers such as potassium titanate whiskers and aluminum borate whiskers, or inorganic fibers such as glass fibers and metal fibers and those obtained by braiding them in a cloth form, and organic compounds such as carbon black, You may add graphite powder, carbon fiber, aramid fiber, polyester fiber, etc.

Further, in order to prevent deterioration of the polyolefin resin due to heat, aging of N, N'-diphenyl-p-phenyldiamine, 2,2'-methylenebis (4-ethyl-6-t-butylphenol) and the like. Inhibitors and 2-hydroxy-4-n-octoxybenzophenone, 2- (2'-hydroxy-3'-t-butyl-5'-methyl
An ultraviolet absorber such as -phenyl) -5-chlorobenzotriazole may be added.

The additive amount of all of the above additives (other than the polyolefin resin and the lubricant) should be not more than 20% by weight of the total amount of the molding raw material as a whole, so that the lubricant supply capacity can be maintained. Above.

As the polymer material which can be used in the present invention, in addition to those based on the above-mentioned polyolefin resin, any thermoplastic resin which can be injection-molded can be used, among which the oil content is increased. What can be used is, for example, a polyester elastomer. In addition to the thermoplastic resin, a thermosetting resin such as a polyurethane or a polyurea elastomer can be used.

In the case of polyurethane, a grease is used as a lubricant, and a urethane prepolymer containing an isocyanate group, which is a reaction raw material, and an amine-based curing agent are uniformly mixed with the grease. The two mixtures are further mixed, filled into bearings, heated and reacted as needed, and cured with grease.

On the other hand, in the case of a polyurea elastomer,
An amine component consisting of a mixture of an aromatic polyamine compound and an aromatic diamine containing a soft segment in the molecular chain is mixed with a lubricating oil compatible with the amine component or a grease having the lubricating oil as a base oil. The polyisocyanate component is added and mixed, filled in a mold having a desired shape, heated and reacted as needed, and cured with a lubricant contained.

As the method of filling the lubricant-containing polymer so that the side end surfaces of the lubricant-containing polymer are arranged inside the side end surfaces of the inner ring and the outer ring, the following two methods can be exemplified. .

One is compression-molding so that a jig having a projection that fits into the gap between the outer periphery of the inner race and the inner periphery of the outer race is sandwiched from above and below (from both sides of the inner race and the outer race).

Second, the lubricant-containing polymer is injection-molded while being held between the same jigs as described above. However, the injection side jig has several through holes that serve as gates on the circumference.

The distance between the side end surface of the lubricant-containing polymer and the side end surfaces of the inner ring and the outer ring is set to be larger than the radius of curvature of the arc-shaped corner formed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring. I do.

When the distance between the side end surface of the lubricant-containing polymer and the side end surfaces of the inner ring and the outer ring is smaller than the radius of curvature of the arc-shaped corner formed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, The rise in temperature causes the lubricant-containing polymer to protrude from the side end surfaces of the inner ring and the outer ring. On the other hand, if the interval is larger than necessary, the filling amount of the lubricant-containing polymer is reduced, and a cage between the inner peripheral surface and the outer peripheral surface,
In some cases, the rolling elements are partially exposed, and the jig for filling the lubricant-containing polymer becomes complicated.

In the method of filling the above-mentioned lubricant-containing polymer, first, a cylindrical roller bearing is assembled by an ordinary method, and then this is subjected to ordinary degreasing and washing. Thereafter, a release agent or grease is applied to the outer peripheral surface of the inner race, the inner peripheral surface of the outer race, the surface of the rolling element, and the surface of the retainer to form a coating (coating) of the release agent or grease.

As the release agent, a fluorine release agent is preferably used. Specifically, a mixture of a perfluoroalkyl group-containing phosphoric acid ester having 4 to 20 carbon atoms or a salt thereof and silicon oil (for example, Japanese Patent Publication No. 53-232)
No. 70, Japanese Patent Publication No. 53-23271),
A mixture of a perfluoroalkyl group-containing phosphoric acid ester having 4 to 20 carbon atoms or a salt thereof and a silicon varnish (for example, described in JP-B-57-48035), a perfluoroalkyl group-containing polyether compound and silicon oil, etc. (For example, described in JP-B-59-32513) and a mixture of a perfluoroalkyl group-containing urethane compound and a ladder polymer of organosilsesquioxane (for example, described in JP-A-63-104804).
And the like. Further, in the mixture,
Those containing no silicon compound can also be used. Further, the fluorine-based release agent contains the above compound as a main component, and contains a suitable solvent (for example, water, isooctane, HCFC-14).
1b).

On the other hand, the type of the grease is not particularly limited, but it is preferable to consider the affinity with the resin forming the lubricant-containing polymer and the lubricant.

That is, in the present invention, the lubricant-containing polymer is once in a molten state at the time of filling. Thus, the resin is in a state in which other components compatible with the resin are most easily taken up. Therefore,
If the grease deposited on the surface of the rolling elements and the resin are compatible, the grease may be incorporated into the molten resin, causing the lubricant-containing polymer to contact the rolling elements and solidify. As a result, the rotation of the rolling element is restricted, and the same effect of reducing the torque by the grease film as in the case of the above-described mold release agent may not be sufficiently exhibited.

Therefore, in the present invention, it is preferable to use a combination of the resin and the lubricant forming the lubricant-containing polymer and the grease with low compatibility.

For example, when the resin of the lubricant-containing polymer is a polyolefin resin, the grease for coating may be:
Fluorine grease (thickener: PTFE, base oil: perfluoropolyether), silicon grease (thickener: lithium soap, base oil: phenylmethyl polysiloxane, dimethyl polysiloxane), which is hardly compatible with hydrocarbon compounds ), Fluorosilicone grease (thickener: lithium soap, base oil: fluorosilicone) and the like are most preferred. In addition, ester greases (thickeners: urea, lithium soap, etc.) based on ester oils having low compatibility due to high polarity even with other hydrocarbons, such as pentaphenyl ether and tetraphenyl ether Polyphenyl ether-based greases based on polyphenyl ether (thickener: bentonite, etc.) can also be used.

When the lubricant-containing polymer resin is a highly polar hydrocarbon compound such as a polyester elastomer, a polyurea elastomer, or a polyurethane, the resin is compatible with the hydrocarbon compound as described above. Most preferred are fluorine-based grease, silicone grease, fluorosilicone grease, etc., which have almost no odor. Contrary to the above, hydrocarbon-based grease is a long-chain hydrocarbon such as phenyl ether with a long hydrocarbon chain such as mineral oil of low polarity, poly-α-olefin oil, octadecyl diphenyl ether, and eicosyl naphthalene. It is possible to use those having low compatibility with naphthalene having a hydrogen chain as a base oil and urea, lithium soap or the like as a thickener.

It is to be noted that the cylindrical roller bearing according to the present invention includes a needle roller bearing in which the rolling element has a needle shape.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a lubricant-containing polymer-filled cylindrical roller bearing and a method of manufacturing the same according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view of a lubricant-containing polymer-filled cylindrical roller bearing according to the present embodiment, and FIG. 2 shows a part of a process of manufacturing the lubricant-containing polymer-filled cylindrical roller bearing shown in FIG. 3 and 4 are enlarged views of a part of FIG. In FIG. 3, other members are omitted so that the relationship between the inner ring and the lubricant-containing polymer can be easily understood. FIG. 4 omits other members so that the relationship between the outer ring and the lubricant-containing polymer can be easily understood.

As shown in FIGS. 1 to 4, the lubricant-containing polymer-filled cylindrical roller bearing 1 according to the present embodiment is interposed between the inner ring 2 and the outer ring 3 and between the inner ring 2 and the outer ring 3. A plurality of cylindrical rollers 4, a lubricant-containing polymer 5 filled in a space formed by the inner ring 2, the outer ring 3 and the cylindrical rollers 4;
And a retainer 6 that retains the cylindrical roller 4.

The side surface 7 of the lubricant-containing polymer 5 has
It is arranged inside the side end surface 8 of the inner race 2 and the side end surface 9 of the outer race 3. Side end surface 7 of lubricant-containing polymer 5 and inner ring 2
The distance between the side end surface 8 of the outer ring 3 and the side end surface 8 of the outer ring 3 is the radius of curvature r of the arcuate corner 10 formed on the outer peripheral surface of the inner ring 2 and the arcuate corner 11 formed on the inner peripheral surface of the outer ring 3. Radius of curvature r
Larger configuration.

In this embodiment, a lubricant-containing polymer 5 having the following composition was used. (Composition) High density polyethylene (classified as relatively low molecular weight) 10% by weight Ultra high molecular weight polyethylene (classified as ultra high molecular weight) 12.5% by weight Polyethylene wax (classified as wax) 2.5% by weight Mineral oil 75% by weight , hardness of the lubricant-containing polymer 5 was a 75HD _a.

Next, a method of manufacturing the lubricant-containing polymer-filled cylindrical roller bearing 1 according to this embodiment will be described.

In this embodiment, a jig 20 used for manufacturing the lubricant-containing polymer-filled cylindrical roller bearing 1 is composed of an upper jig 21 and a lower jig 22, as shown in FIG. It is configured. The jig 20 is an upper jig 21
And the lower mold jig 22, but the arrangement is not limited, such as left and right.

The upper jig 21 includes an outer peripheral portion of the inner race 2 and the outer race 3.
Has a convex portion 23 that is just inserted. The lubricant-containing polymer 5 corresponds to the protrusions 23.
Are located inside the side end surface 8 of the inner race 2 and the side end surface 9 of the outer race 3. Further, a pin gate 25 for material injection is formed on the upper jig 21. Upper jig 21
A screw hole 26 into which a part of a screw 29 to be described later is screwed is formed substantially in the center of the surface on the side facing the lower jig 22.

The lower jig 22 includes an outer peripheral portion of the inner ring 2 and the outer ring 3.
Has a convex portion 24 that is just inserted. The lubricating polymer 5
Are located inside the side end surface 8 of the inner race 2 and the side end surface 9 of the outer race 3. A screw 29 for joining the lower jig 22 and the upper jig 21 is provided at the center of the lower jig 22.
A screw hole 27 is formed in the vertical direction with respect to the upper surface of the lower jig 22. Screw 2 in screw holes 27 and 26
By screwing 9, the lower jig 22 is joined to the upper jig. Reference numeral 30 is a stupid hole.

In order to manufacture the lubricant-containing polymer-filled cylindrical roller bearing 1, first, the cylindrical roller bearing is assembled by a normal method, and then subjected to a normal degreasing cleaning. Then, inner ring 2
A release agent or grease is applied to the outer peripheral surface of the outer ring 3, the inner peripheral surface of the outer ring 3, the surface of the cylindrical roller 4, and the surface of the cage 6 to form a coating film (coating) of the release agent or grease.

The coating film of the release agent may be prepared by, for example, using a fluorine-based release agent as it is or an appropriate diluent (for example, water,
(E.g., isooctane, HCFC-141b, etc.) and spraying or brushing each of the above-mentioned portions, or immersing the cylindrical roller bearing in a solvent or dispersion containing the above-mentioned release agent. . At this time, the application amount of the release agent is not particularly limited, but it is preferable that the release agent is uniformly applied so as to have a film thickness of about 0.1 to 1.0 μm.

The method of forming a grease coating (coating film) is not particularly limited. For example, after a small amount of grease is filled in the bearing, the bearing is rotated to form the inner peripheral surface of the outer ring 3 and the inner ring 2. Outer peripheral surface, surface of cylindrical roller 4, and cage 6
There is a method of forming a grease coating on the surface. Other methods include dissolving the grease in a solvent such that the base oil dissolves and the thickener is evenly distributed, then immersed in the solution, and then dried to remove the solvent. In this way, a film can be formed. The thickness of the grease coating is preferably 10 to 1000 μm.

Then, as shown in FIG. 2, the lubricant-containing polymer 5 having the above-mentioned composition was held in a state where the bearing was held in a mold.
Injection molding (insert molding), as shown in FIG.
The distance between the side end surface 7 of the lubricant-containing polymer 5 and the side end surfaces 8 and 9 of the inner ring and the outer ring is the radius of curvature of the arc-shaped corners 10 and 11 formed on the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 3. Fill so as to be larger than r.

In this injection molding, an injection molding machine according to the one described in Japanese Patent Application Laid-Open No. Hei 8-309793 by the present applicant was used.

In the present embodiment, the arc-shaped corner 10
And 11, the radius of curvature r was set to 1.0 mm, and the distance between the side end faces 7 and the side end faces 8 and 9 was set to 1.1 mm.

Next, as a comparative example, the cylindrical roller bearing J2311W (r = 1.0 mm, the distance between the side end face 7 and the side end faces 8 and 9 = 1.1 mm) manufactured in the present embodiment was used.
The dynamic torque was measured for the lubricant-filled polymer filled up to the bearing-side end face.

The evaluation was made such that the dynamic torque of the comparative example was 100
Went as. Table 1 shows the results. From Table 1, it was confirmed that the lubricant-containing polymer-filled cylindrical roller bearing 1 according to the present embodiment achieved lower torque than the conventional one.

[0058]

As described above, in the lubricant-containing polymer-filled cylindrical roller bearing according to the present invention, the side surfaces of the lubricant-containing polymer are closer than the side surfaces of the inner ring and the outer ring to the outer peripheral surface of the inner ring and the inner ring. Since it is arranged inside with an interval larger than the radius of curvature of the arc-shaped corner formed on the peripheral surface, even if it expands from the inner ring and outer ring due to temperature rise, the lubricant-containing polymer protrudes from the side end surfaces of the inner ring and outer ring Can be prevented. Further, since the lubricant-containing polymer can be prevented from covering the arcuate corners formed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring, lower torque can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a lubricant-containing polymer-filled cylindrical roller bearing according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a part of a step of manufacturing the lubricant-containing polymer-filled cylindrical roller bearing shown in FIG.

FIG. 3 is a partially enlarged view of FIG. 1;

FIG. 4 is an enlarged view of a part of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lubricated polymer filled cylindrical roller bearing 2 Inner ring 3 Outer ring 4 Cylindrical roller 5 Lubricated polymer 7, 8, 9 End face 10 Arc-shaped corner

Claims (1)

[Claims] An inner ring and an outer ring, a plurality of rolling elements interposed between the inner ring and the outer ring, and a lubricant-containing polymer filled in a space formed by the inner ring, the outer ring and the rolling elements. In the lubricant-containing polymer-filled cylindrical roller bearing, the lubricant-containing polymer has a side end face located inside the side end faces of the inner ring and the outer ring, and has a side end face of the lubricant-containing polymer, the inner ring and A lubricant-filled polymer-filled cylindrical roller bearing in which the distance from the side end surface of the outer ring is larger than the radius of curvature of the arcuate corners formed on the outer peripheral surface of the inner ring and the inner peripheral surface of the outer ring.