JP2000319681A - Lubricant composition for rolling bearing and rolling bearing filled with the lubricant composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lubricant compsn. for rolling bearings having a long life even under a severe conditions and made substantially free from maintenance. SOLUTION: This lubricant compsn. for rolling bearing contains an urethane polymer (a) contg. 6-10 wt.% isocyanate group, a grease (b) selected from a metal soap type grease and a non-metal soap type grease, and an amine curing agent (c), and the hardness after curing is 60-85 in International Rubber Hardness unit (IRHD). And this bearing is filled with the compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubricant composition for a bearing, which is useful for extending the life of a rolling bearing and making it maintenance-free, and to a rolling bearing filled with the lubricant composition.

[0002]

2. Description of the Related Art Rolling bearings serve to support rotating shafts, and the space between the outer ring, inner ring and rolling elements is filled with a lubricant composition to impart lubricity. Have been. In addition to being easy to use, this lubricant composition is required to withstand a long period of time without losing its performance even under severe use conditions such as high temperature, high speed rotation and high load.

[0003] Various lubricant compositions for rolling bearings have been developed so far. Among them, there are polymer lubricants that apply lubricating oil or grease to prevent the lubricant from scattering and dripping at the place where lubrication has been performed, and to extend the life of the bearing and make it maintenance-free. . As this lubricant, a polyethylene resin which is a thermoplastic resin is used, and its melting point is low, so that the maximum use temperature is about 80 ° C. (JP-B-47-3455, JP-B-63-2323).
No. 9). Many of the commonly used rolling bearings are used at about 120 ° C., and there are limits to the specifications of conventional polymer lubricants.

[0004]

As described above, the use of a polymer lubricant for a rolling bearing has been considered. However, practically, it can be used at a higher temperature, and has a longer life and a maintenance-free operation. What can be done is desired. Therefore, as a resin having excellent heat resistance, there is a polymer lubricant using a polyurethane resin which is a thermosetting resin, and use at a high temperature can be expected (Japanese Patent Laid-Open No. 6-17 / 1994).
2770, JP-A-7-268376, JP-A-8-325585).

According to the studies made by the present inventors, polymer lubricants using these polyurethane resins differ in hardness when cured into a rolling bearing after filling into a rolling bearing due to the difference in components, and the properties are also different. It turns out to be very different. Therefore, an object of the present invention is to provide a so-called maintenance-free polymer lubricant, which is easy to use and has a long life even under high temperature conditions, so that once it is filled in a rolling bearing, subsequent replacement is unnecessary. An object of the present invention is to provide a lubricant composition for a rolling bearing and a rolling bearing filled with the lubricant composition.

[0006]

Means for Solving the Problems In order to solve the above problems, the present inventors have found that a polymer lubricant using a polyurethane resin is a thermosetting resin having excellent heat resistance.
Noting that use at high temperatures can be expected, various effects of components and properties were examined in order to extend the lubrication life of the rolling bearing filled with the resin-based polymer lubricant, and as a result, the present invention was completed. .

That is, the present invention provides: 1) (a) a urethane prepolymer having an isocyanate group content of 6 to 10% by weight, (b) a grease selected from metallic soap type grease and non-metallic soap type grease, and c) The composition contains an amine-based curing agent and has a cured hardness of 6 in international rubber hardness unit (IRHD, a measuring method described in JIS K6253).
The present invention relates to a lubricant composition for a rolling bearing, which is characterized by being 0 to 85, and 2) a rolling bearing filled with the lubricant composition for a rolling bearing described in the above 1).

[0008]

DETAILED DESCRIPTION OF THE INVENTION As the urethane prepolymer which is the component (a) of the lubricant composition of the present invention, the one having an isocyanate group content of 6 to 10% by weight is used. The molecular weight is preferably about 400 to 10,000. A lubricant composition using a polymer having an isocyanate group content of less than 6% by weight does not reach a hardness of 60 IRHD after curing and tends to increase torque during operation even when filled into a bearing. Since the object is also damaged, the purpose of extending the life cannot be fulfilled. On the other hand, when the content of the isocyanate group exceeds 10% by weight, the supply of oil from the lubricant composition is reduced, and the life is shortened, so that it is not suitable as a bearing lubricant.

The urethane prepolymer which is the component (a) of the lubricant composition of the present invention includes, for example, Hyprene H
L-951, Hyprene HL-6502, Hyprene L
-315, Hyprene AX-596C, Hyprene P-
Commercially available products such as 760 (all of them are manufactured by Mitsui Chemicals, Inc.). The grease which is the component (b) of the lubricant composition of the present invention is selected from a metal soap type grease and a non-metal soap type organic grease. Examples thereof include greases containing an alkali metal salt, an alkaline earth metal salt or an aluminum salt of an aliphatic monocarboxylic acid having 12 to 24 carbon atoms as a thickener: 12 g atoms containing at least one hydroxyl group. Grease containing as a thickener an alkali metal salt or an alkaline earth metal salt of an aliphatic monocarboxylic acid having from 24 to 24 carbon atoms, at least one aliphatic monocarboxylic acid having from 12 to 24 carbon atoms, at least one hydroxyl group A calcium complex soap grease containing a fatty acid having 12 to 24 carbon atoms and a calcium salt of an aliphatic monocarboxylic acid having 2 to 11 carbon atoms containing a thickener;
Aluminum complex soap grease using an aliphatic monocarboxylic acid of 4 and an aluminum salt of an aromatic monocarboxylic acid having 7 to 24 carbon atoms as a thickener; at least one aliphatic mononocarboxylic acid having 12 to 24 carbon atoms An acid, an aliphatic monocarboxylic acid having from 12 to 24 carbon atoms containing at least one hydroxyl, and at least one aliphatic dicarboxylic acid or diester dicarboxylic acid having from 2 to 12 carbon atoms, or from 7 to 7 carbon atoms. Lithium complex soap grease using a lithium salt of an aromatic monocarboxylic acid or a monocarboxylic acid ester or a phosphoric acid ester or a boric acid ester as a thickener; a diurea compound (R ¹ NHCONHR ² NHCO
In the formula represented by NHR ¹ , R ¹ represents a linear or branched saturated or unsaturated alkyl group having 6 to 24 carbon atoms, and R ² represents a divalent aromatic having 6 to 15 carbon atoms. Represents a group hydrocarbon group. Grease).

The base oil in these greases is used for ordinary lubricating grease.
A synthetic hydrocarbon oil having a kinematic viscosity at 20 to 100 mm ² / s (eg, poly-α-olefin oil) is preferably used. As the amine curing agent, which is the component (c) of the lubricant composition of the present invention, those having an amino group content of 1 to 10% by weight are suitable. Such amine-based curing agents include, for example, MC-506, MC-591, MDA-2
Aromatic polyamine-based curing agents such as No. 20 (all manufactured by Mitsui Chemicals, Inc.), Adeka Hardener CA125 (Asahi Denka Kogyo), Etacure 100 (Albemar Asano), Wandamine HM (4,4'-diaminodicyclohexylmethane) (new Nippon Rika), alicyclic amine curing agents such as 1,2-diaminocyclohexane (Dupont), hexamethylenediamine (Dupont), ethylenediamine (Kanto Denka Kogyo), Trilon BS (ethylenediaminetetraacetic acid)
(BASF) and aliphatic amine-based curing agents such as Jeffamine D-2000 (polyoxyalkylenediamine) (Mitsui Texaco Chemical).

The lubricant composition of the present invention generally comprises 18.3 to 79.6% by weight of the urethane prepolymer of component (a); 20 to 80% by weight of grease of component (b); and component (c). ) Is prepared so as to contain 0.1 to 6.7% by weight of the curing agent. In the above lubricant composition, the total amount of the components (a) and (c) is preferably 20 to 80% by weight, more preferably 4% by weight, based on the total weight of the composition.
0 to 60% by weight. If the amount is less than 20% by weight, the lubricant composition is too soft and does not become a solid lubricant. Also,
When the content exceeds 80% by weight, the lubricant composition is too hard and becomes a state close to a resin, so that the lubricant does not spread much and poor lubrication is likely to occur.

The weight ratio of component (a) to component (c) is preferably from 200: 1 to 11: 1, more preferably 50:
1 to 20: 1. When the ratio of the component (a) is lower than 200: 1, the curing speed (time until solidification) becomes slow, which is not practical, and the ratio of the component (c) is 11: 1.
Beyond is not economical. In the present invention, the hardness after curing of the lubricant composition is set so as to be in the range of 60 to 85 IRHD. Is achieved by doing If the hardness is less than 60 IRHD, there is a high possibility that the bearing will be damaged and the life will be shortened. On the other hand, if the hardness exceeds 85 IRHD, the oil supply will be reduced,
As a result, the service life of the bearing is reduced, and it is difficult to achieve the maintenance-free purpose.

[0013] The lubricant composition of the present invention may optionally contain
Additives such as antioxidants, rust preventive additives and extreme pressure additives may be added. The lubricant composition of the present invention is obtained by mixing the above-mentioned compounds in the above-mentioned ratios and curing. In these steps, the urethane prepolymer and the grease containing the amine-based curing agent are mixed in the rolling bearing using a static mixer or a reaction injection molding device so that the curing of the urethane prepolymer is performed after filling the rolling bearing. It is preferable to carry out the mixing so as to perform the mixing together. When filling with a static mixer or the like, the amine-based curing agent is blended in (b) grease, and is usually blended so that the lubricant composition is in a mixed state at a predetermined blending ratio in the rolling bearing. Preferably. Other additives may be added to (a) and / or (b) or both in a predetermined amount.

The lubricant composition of the present invention is usually cured by filling the inside of the rolling bearing as described above and then leaving it at a temperature of room temperature to 170 ° C. for about several minutes to 24 hours.

[0015]

The present invention will be described more specifically below with reference to examples and comparative examples. Examples 1-3, Comparative Examples 1-4 Urethane prepolymer, grease, and aromatic polyamine-based curing agent were blended with the composition (unit:
% By weight) and heated at 170 ° C. for 15 minutes to cure.

[0016]

[Table 1]

[Evaluation Tests] Examples 1 to 3 and Comparative Examples 1 to 4
Each of the lubricant compositions obtained in and the rolling bearings filled with the lubricant compositions were evaluated by the following methods. 1) Hardness measurement The hardness after curing is measured by the measuring method described in JIS K6253.
It was measured.

2) Life Test A life test was carried out under the conditions shown in Table 2 using the obtained deep groove ball bearing 6205 filled with the lubricant composition.

[0019]

[Table 2]

The criterion for determining the life is to increase the torque (58.
8 N · cm or more) and temperature rise (outer ring temperature 160 ° C. or more). In the test, two sample bearings were included in one shaft, and the time when one of them reached the end of its life was defined as the life time. The test was repeated twice each. 3) Oil Degree Test The obtained lubricant composition was made into a cylindrical test piece of φ10 × 10 mm, placed on a filter paper and left in a thermostat adjusted to 120 ° C., and the oil separation after 480 hours was measured. It was measured.

As a result of the evaluation test (Table 1), the hardness after curing was 6
Those having 0 to 85 have a life of 5000 hours or more. When the hardness is 60 or less, the lubricant is damaged, and the life is extremely shortened. On the other hand, when it is 85 or more, the degree of oil separation is reduced and the life is shortened. Therefore, a lubricant having a urethane prepolymer content of 6 to 10% and a hardness after curing of 60 to 85 can be used as a lubricant for a rolling bearing and is a polymer lubricant having excellent heat resistance. .

[0022]

The bearing filled with the lubricant composition of the present invention has a long service life, and can achieve the maintenance-free object which does not require replacement after installation.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C10M 117/04 C10M 117/04 133/04 133/04 149/14 149/14 149/20 149/20 F16C 33/66 F16C 33/66 Z // C10N 10:02 10:04 10:06 20:00 30:00 40:02 (72) Inventor Hiroshi Komiya Koyo Seiko shares 3-5-8 Minamisenba, Chuo-ku, Osaka-shi Inside the company (72) Inventor Yasushi Yasugashi 1-4-4 Tsujido Shindai, Fujisawa-shi, Kanagawa Prefecture Inside Kyodo Yushi Co., Ltd.Tsujido Factory (72) Inventor Hiroshi Kimura 1-4-4 Tsujido Shindai, Fujisawa-shi, Kanagawa Prefecture Kyodo Yushi Co., Ltd. In-plant F term (reference) 3J101 AA01 CA12 CA40 EA64 FA32 FA48 4H104 BB16B BB17B BB19B BB22B BB33B BE02R BE06R BE07R BE13B BH03B BJ05B CE13A CE13R CE14A CE19R EA01Z EA05Z EB02 FA01 FA02 FA20

Claims (2)

[Claims] (1) The content of (a) an isocyanate group is 6 to 1
0% by weight of a urethane prepolymer, (b) a grease selected from a metallic soap-type grease and a non-metallic soap-type grease, and (c) an amine-based curing agent. IRHD) 60-85
A lubricant composition for rolling bearings, characterized in that: 2. A rolling bearing filled with the lubricant composition according to claim 1.