JP2003239997A - Rolling bearing for electromagnetic clutch, compressor, and idler pulley - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing for an electromagnetic clutch, a compressor, and an idler pulley having improved seizure service life at a high temperature exceeding 180°C and resistance to rust. <P>SOLUTION: This rolling bearing for the electromagnetic clutch and the idler pulley is constituted in such a way that it retains a plurality of rolling elements 13 between an inner ring 10 and an outer ring 11 so as to roll freely, and mixed grease produced by mixing fluorine grease containing perfluoropolyether oil as base oil and polytetrafluoroethylene as thickener with grease other than fluorine grease is filled in the rolling bearing. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in parts for use under high temperature, high speed and high load conditions such as parts for automobile electrical equipment, electromagnetic clutches for car air conditioners which are engine accessories, compressors and idler pulleys. Regarding rolling bearings.

[0002]

2. Description of the Related Art Due to the demand for smaller and lighter automobiles and further expansion of living space, the engine room space is inevitably reduced, and electrical components and engine accessories are being made smaller and lighter. Electromagnetic clutches, compressors and idler pulleys are no exception. However, the reduction in output is inevitable due to the miniaturization, and the reduction in output is compensated for by increasing the speed of the electromagnetic clutch, and the idler pulley also increases in speed accordingly. Further, due to the demand for quietness improvement, the sealing of the engine room is promoted, and the temperature rise in the engine room is promoted. Therefore, it is also necessary for these parts to withstand high temperatures. In addition, since these parts are often installed in the lower part of the engine room, rainwater and muddy water are likely to be splashed during running, and the grease used for the rolling bearings for these parts can be damaged by other parts. A grease with better rust prevention performance than the grease used in is required.

At present, a urea-synthetic oil-based grease containing a synthetic oil as a base oil and a urea compound as a thickener is mainly used for rolling bearings for electromagnetic clutches, rolling bearings for compressors, and rolling bearings for idler pulleys. The bearing lubrication life is long up to a temperature of 170 to 180 ° C., and it can be sufficiently used.

However, in recent years, many have been attempting to reduce the weight by changing the pulley material of the electromagnetic clutch, compressor and idler pulley from metal to resin. Resin has a lower heat dissipation than metal, so the bearing temperature becomes higher and higher, and the temperature may exceed 180 ° C. When the urea-synthetic oil type grease is used at 180 ° C. or higher, evaporation of the base oil becomes severe, the grease is hardened, and sometimes the thickener is broken and softened, so that seizure occurs early.

From such a background, Japanese Patent Laid-Open No. 2000-27
Japanese Patent No. 3478 and Japanese Patent Laid-Open No. 2000-303088 describe that a fluorine-based grease is enclosed in a rolling bearing to improve heat resistance. However, this rolling bearing, which can be used in a high temperature range of 200 ° C., is effective only under a low load, and generates a large amount of heat under a high load, causing seizure at an early stage. Further, a rust preventive agent is generally added to enhance the rust preventive performance, but the rust preventive agent that can be added to the fluorine-based grease is limited, and the rust preventive property is inferior to that of the urea-synthetic oil grease. It also has the disadvantage of being expensive and expensive.

[0006]

As described above, the conventional urea-synthetic oil type grease is difficult to use at a high temperature of 180 ° C. or higher, and the fluorine type grease is also heat resistant and rustproof under high load. It is not sufficient as a grease for rolling bearings used in electromagnetic clutches, compressors, and idler pulleys, for which high temperature, high speed and high load are expected to increase in the future.

The present invention has been made in view of the above circumstances, and is a rolling bearing for electromagnetic clutches, compressors, and idler pulleys, which has improved seizure life and rust prevention at high temperatures exceeding 180 ° C. The purpose is to provide.

[0008]

In order to achieve the above object, the present invention is for an electromagnetic clutch in which a plurality of rolling elements are rotatably held between an inner ring and an outer ring and grease is enclosed. In rolling bearings for compressors and idler pulleys, the grease is a mixed grease of a fluorine-based grease containing perfluoropolyether oil as a base oil and polytetrafluoroethylene as a thickener, and a grease other than a fluorine-based grease. A rolling bearing for an electromagnetic clutch, a compressor, and an idler pulley is provided.

In the rolling bearing for electromagnetic clutches, compressors, and idler pulleys of the present invention, a mixed grease of a fluorine-based grease and a grease other than the fluorine-based grease is sealed, so that the fluorine-based grease has an excellent high temperature. Durability is maintained, and various rust preventive agents can be added to greases other than fluorine-based grease, so rust preventive property is also enhanced. Also, since the high temperature durability is maintained by the fluorine grease, the viscosity of the base oil as a whole of the mixed grease can be kept low, the low temperature fluidity of the encapsulated grease is enhanced, and as a result, the startability at low temperatures is also excellent. become. Further, since a grease other than the fluorine-based grease is blended, there is an advantage that it is less expensive than a case where the entire grease is a fluorine-based grease.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, for an electromagnetic clutch of the present invention,
The rolling bearings for the compressor and the idler pulley will be described in detail.

In the present invention, the structure of the bearing itself is not limited, and a ball bearing 1 shown in a sectional view in FIG. 1 can be exemplified. The ball bearing 1 rotatably holds a plurality of balls 13, which are rolling elements, between an inner ring 10 and an outer ring 11 via a cage 12, and further, the inner ring 1
The bearing space S formed by the outer ring 0, the outer ring 11 and the balls 13 is filled with a mixed grease (not shown) which will be described later and sealed by a seal member 14.

The mixed grease is a mixture of a fluorine-based grease containing perfluoropolyether oil as a base oil and polytetrafluoroethylene as a thickener, and a grease other than the fluorine-based grease. Hereinafter, each grease will be described in detail.

[Fluorine-based grease] In the fluorine-based grease, abnormal noise is generated at low temperature startup due to insufficient low temperature fluidity,
In order to avoid seizure that occurs due to the difficulty of forming an oil film at high temperatures, the vulcanizable viscosity at 40 ° C. is 20 to 400 mm ² / s, especially 30 to ^{2 as the} parble oropolyether oil.
It is preferable to use one having a diameter of 00 mm ² / s.

The polytetrafluoroethylene is not particularly limited, and those generally used for fluorine grease can be appropriately used. The shape may be spherical, polyhedral (cubic or rectangular parallelepiped), or extremely needle-like.

The content of polytetrafluoroethylene in the fluorine-based grease is 10 to 45% by mass, preferably 15 to 35% by mass. If the content of polytetrafluoroethylene is less than 10% by mass, heat resistance cannot be obtained, and 4
If it exceeds 5% by mass, the grease becomes too hard.

[Grease Other than Fluorine-based Grease] As the grease other than the fluorine-based grease, metal complex soap-based grease and urea-based grease are preferable.

The base oil used in this metal complex soap grease or urea grease is
The kinematic viscosity at 40 ° C. is preferably 10 in order to avoid abnormal noise when starting at low temperature due to insufficient low-temperature fluidity of grease and seizure that occurs when an oil film is hard to form at high temperature.
~ 400 mm ² / sec, more preferably 20-250 mm ² / s
ec, more preferably 40 to 150 mm ² / sec.

Further, as the type of the base oil, mineral oil type and synthetic oil type lubricating oils can be said to be suitable since additives such as rust preventives can be easily contained. The mineral oil-based lubricating oil is preferably a mineral oil refined by appropriately combining distillation under reduced pressure, solvent degassing, solvent extraction, hydrocracking, solvent dewaxing, sulfuric acid washing, clay refining, hydrorefining and the like. Examples of synthetic oil-based lubricating oils include hydrocarbon oils, aromatic oils, ester oils and ether oils. Examples of the hydrocarbon-based oil include normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, poly-α-olefins such as 1-decene and ethylene cooligomers, and hydrides thereof. Examples of the aromatic oil include alkylbenzene such as monoalkylbenzene and dialkylbenzene, and alkylnaphthalene such as monoalkylnaphthalene, dialkylnaphthalene and polyalkylnaphthalene. Examples of the ester oil include dibutyl sebacate, di-2-ethylhexyl sebacate, dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, and methyl acetyl cinnolate, or trioctyl trimellitate, Aromatic ester oils such as tridecyl trimellitate and tetraoctyl pyromellitate, and polyols such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, pentaerythritol belargonate Ester oil, and further, complex ester oil which is an oligoester of polyhydric alcohol and mixed fatty acid of dibasic acid / monobasic acid, and the like can be mentioned. As an ether oil,
Polyethylene glycol, polypropylene glycol,
Polyglycol such as polyethylene glycol monoether and polypropylene glycol monoether, or phenyl ether oil such as monoalkyl triphenyl ether, alkyl diphenyl ether, dialkyl diphenyl ether, pentaphenyl ether, tetraphenyl ether, monoalkyl tetraphenyl ether and dialkyl tetraphenyl ether. Etc. These base oils can be used alone or as a mixture, and are adjusted to the preferable kinematic viscosity described above. Among these base oils, ether-based oils and ester-based oils, which have a relatively high affinity with the perfluoropolyether oil that is the base oil of the fluorine-based grease, are preferably used.

Examples of the thickener for the metal complex soap type grease include metal complex soap selected from Li, Na, Ba, Ca and the like, or a mixture thereof. Examples of the thickener for urea grease include diurea compounds, triurea compounds, tetraurea compounds, polyurea compounds, and mixtures thereof. These thickeners can be used alone or as a mixture.

Further, the amount of the thickener of the metal complex soap type grease and the urea type grease is 5 to each.
It is in the range of 40% by mass, preferably 10 to 30% by mass. If the amount of the thickener is less than 5 mass, grease cannot be formed, and if it exceeds 40 mass%, the grease becomes too hard.

As for the above-mentioned metal complex soap-based grease and urea-based grease, either one of them can be used, or both greases can be used in combination, if necessary. Considering the heat resistance and acoustic properties of the resulting grease, it is desirable to use urea grease. When both greases are used in combination, the compounding ratio of the metal complex soap-based grease and the urea-based grease can be appropriately set as needed.

[Composition of Mixed Grease] The mixed grease used in the present invention is a mixture of the above-mentioned fluorine-based grease and a grease other than the fluorine-based grease, and the compounding ratio thereof is the desired heat resistance and rust resistance. Is selected in consideration of the above. However, when at least one of the metal complex soap-based grease and the urea-based grease is selected as grease other than the fluorine-based grease, at least one of the metal complex soap-based grease and the urea-based grease is in a mass ratio: fluorine-based grease = 30 to 80:70
It is preferable to mix at a ratio of -20. If more than 70% by mass of fluorine-based grease is blended, the amount of metal complex soap and urea-based grease is too small, and the blending ratio of mineral oil and synthetic oil contained as base oil in them is reduced, so an effective amount of rust preventive agent is used. Since it cannot be added, sufficient rust prevention cannot be obtained. Moreover, since the amount of fluorine grease increases, the raw material cost of the mixed grease becomes as expensive as the fluorine grease. On the other hand, fluorine grease is 2
If it is less than 0% by mass, sufficient heat resistance cannot be imparted to the mixed grease and the seizure life becomes short.

Further, the total amount of the thickener in the mixed grease, that is, the total amount of metallic soap, urea compound and polytetrafluoroethylene is set to 15 to 35% by mass. When the total amount of the thickener in the mixed grease is less than 15% by mass,
Due to large oil separation and poor shear stability,
Grease leaks and shortens the seizure life. Also,
When it exceeds 35% by mass, the fluidity of the mixed grease becomes large, and the grease does not enter the rolling surfaces of the bearing inner and outer races and the rolling elements, which causes problems with seizure life and low temperature.

[Consistency of mixed grease] Further, the consistency of the mixed grease is such that when the fluorine-based grease and a grease other than the fluorine-based grease are mixed, NLG is obtained after the mixing.
I No. It is more desirable that it is 1 to 3.

[Additive] In order to further enhance the performance of the mixed grease, known general additives conventionally used in greases may be added, if necessary. The additive is added to the metal complex grease or the urea grease due to the solubility of the base oil.
Examples of the additives include gelling agents such as benton and silica gel; amine-based, phenol-based, sulfur-based, zinc dithiophosphate and other antioxidants; chlorine-based, sulfur-based, phosphorus-based,
Extreme pressure agents such as zinc dithiophosphate and organic molybdenum; oily agents such as fatty acids and animal and vegetable oils; anticorrosive agents such as petroleum sulfonate, dinonylnaphthalene sulfonate, sorbitan ester; metal inactive such as benzotriazole and sodium nitrite Agents: Viscosity index improvers such as polymethacrylate, polyisobutylene, polystyrene and the like can be mentioned, and these can be added alone or in combination of two or more kinds.
Above all, the rolling bearing for the electromagnetic clutch and the idler pulley of the present invention is preferably used in an environment where it is exposed to high temperature and water, and therefore it is preferable to add an antioxidant or a rust preventive. The addition amount of these additives is not particularly limited as long as the intended purpose of the present invention can be achieved, but is preferably 20% by mass or less of the total amount of the mixed grease.

[Production Method of Mixed Grease] There is no limitation on the production method of fluorine grease and greases other than fluorine grease, and any of them can be obtained by reacting a thickener in a base oil. When the additives are added, it is necessary to add the additives and then sufficiently stir and knead them by a stirring and kneading means such as a kneader or a roll mill to uniformly disperse them.
It is also effective to heat during the stirring and kneading. Also for fluorine grease, mix perfluoropolyether oil with polytetrafluoroethylene powder,
It is obtained by kneading with a three-stage roll mill or the like.

Then, a fluorine-based grease and a grease other than the fluorine-based grease are blended in a predetermined ratio, sufficiently stirred and kneaded by a kneader, roll mill, or other kneading means to uniformly disperse each other. , Mixed grease is obtained. When performing this treatment, heating is also effective.

[0028]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[Test 1] (Preparation of mixed grease) Obtained by reacting an ester oil mixed with diisocyanate (kinematic viscosity at 40 ° C. of 120 mm ² / s) with the same ester oil mixed with amine and stirring and heating. To the semi-solid product, an amine antioxidant previously dissolved in the same ester oil was added and sufficiently stirred to prepare a urea grease. The content of the diurea compound, which is a thickener, was set to 25% by mass.

Further, perfluoropolyether oil (40
Polytetrafluoroethylene powder was sufficiently mixed in a kinematic viscosity at 190 ° C. of 190 mm ² / s) at a ratio of 30% by mass, and kneading was performed by a three-stage roll mill to prepare a fluorine-based grease.

Then, the urea-based grease and the fluorine-based grease were mixed at the mass ratio shown in Table 1 and then passed through a roll mill to obtain a test mixed grease.
The consistency of the test mixed grease is NLGI.
No. It is adjusted to be 1 to 3. Then, the obtained mixed grease for test was sealed in a test bearing, and a high temperature seizure life test and a rust prevention test shown below were performed.

[0032]

[Table 1]

(High-temperature seizure life test) A mixed-row angular contact ball bearing with an inner diameter of 35 mm, an outer diameter of 52 mm, and a width of 22 mm with a contact rubber seal was filled with mixed grease for each test in a space volume of 2
A test bearing was manufactured by enclosing it so as to occupy 4%. The test was performed using the test apparatus shown in FIG. In the illustrated test apparatus, the pulley 20 in which the test bearing 23 is press-fitted is attached to the belt 2
It is configured to rotate at 1, and at that time, the inner ring is heated by the cartridge heater 22 and controlled to the test temperature. In the test, the test bearing 23 was rotated with the outer ring rotating speed of 10,000 mi.
n ^-1 , bearing inner ring temperature 190 ° C, radial load 980N, seizure occurs and bearing inner ring temperature 200
The test was terminated when the temperature rose above ° C and when the rotational torque rose sharply, and the time until then was measured. The test is performed 4 times for each test bearing 23, and the average value is used as
A burn-in time of 3 was used. The results are shown in the graph of FIG. 3, and the seizure life time of 300 hours or more is acceptable.

(Rust prevention test) Inner diameter 17 mm, outer diameter 47 m
m, width 14mm, rubber seal with deep groove ball bearing, each test
Fill the mixed grease so that it occupies 50% of the space volume
1800min ^-1Rolled in for 30 seconds. That
Then, 0.5 cc of salt water 0.5 cc is poured into this ball bearing.
Water and re-1800 min^-1And break it in for 30 seconds
It was Next, keep this ball bearing at 80 ℃ and 100% RH
After leaving it in the constant temperature and humidity chamber for 48 hours, it is disassembled and
The rust condition on the road surface was visually observed. Rust evaluation of this rust test
The points and rust conditions are as shown below. # 7: No rust # 6: Stain rust (stainless minute rust) # 5: Spot rust (φ 0.3 mm or less) # 4: Small rust (φ 1.0 mm or less) # 3: Medium rust (φ 5.0 mm or less) # 2: Large rust (φ10.0mm or less) # 1: Extreme rust (rust almost all over the surface) It should be noted that # 7 to 5 were good and # 5 to 1 were bad. result
Is shown in the graph in FIG.

As shown in FIG. 3, by enclosing mixed grease in which the mixing ratio of the urea-based grease is in the range of 30 to 80% by mass and the total amount of the thickener is in the range of 15 to 35% by mass, It can be seen that it is possible to suppress the occurrence of rust while improving the seizure life.

[Test 2] (Preparation of mixed grease) After saponification reaction of 12-hydroxystearic acid and lithium hydroxide (primary saponification reaction), dibasic acid and lithium hydroxide were added to conduct saponification reaction (secondary reaction). (Saponification reaction) and 180 ° C after the saponification reaction
It was heated to the temperature of ether oil (Kinematic viscosity at 40 ℃ 1
(30 mm ² / s) was added, the mixture was cooled to room temperature, an amine-based antioxidant was added, and then kneading was performed by a three-stage roll mill to prepare a lithium complex soap-based grease. The content of lithium complex soap, which is a thickener, was set to 25% by mass.

Further, perfluoropolyether oil (40
Kinematic viscosity at 60 ° C. of 60 mm ² / s) was sufficiently mixed with polytetrafluoroethylene powder at a ratio of 22 mass%,
Kneading with a three-stage roll mill was performed to prepare a fluorine-based grease.

Then, the lithium complex soap type grease and the fluorine type grease were mixed at the mass ratio shown in Table 2, and then passed through a roll mill to obtain a test mixed grease. The consistency of the test mixed grease is NLGI No. It is adjusted to be 1 to 3.

[0039]

[Table 2]

Then, the test mixed grease thus obtained was filled in a test bearing, and the same high temperature seizure life test and rust prevention test as in Test 1 were conducted. The results are shown in a graph in FIG. 4, and the mixed grease in which the mixing ratio of the lithium complex soap-based grease is in the range of 30 to 80 mass% and the total amount of the thickener is in the range of 15 to 35 mass% is enclosed. As a result, it can be understood that the seizure life can be improved and the occurrence of rust can be suppressed.

[0041]

As described above, according to the present invention,
Provided are rolling bearings for electromagnetic clutches, compressors, and idler pulleys, which have both heat resistance exceeding 180 ° C. and rust prevention.

[Brief description of drawings]

FIG. 1 is a sectional view showing a ball bearing which is an embodiment of a rolling bearing of the present invention.

FIG. 2 is a schematic diagram showing a test apparatus used for a high temperature seizure durability test in Examples.

FIG. 3 is a graph showing the relationship between the mixing ratio of urea-based grease, the seizure life time, and the rust evaluation point obtained in Test 1.

FIG. 4 is a graph showing the relationship between the mixing ratio of the lithium complex soap-based grease, the seizure life time, and the rust evaluation point obtained in Test 2.

[Explanation of symbols]

1 ball bearing 10 inner ring 11 outer ring 12 cage 13 balls 14 Seal member 20 pulley 21 belt 22 Cartridge heater 23 Test bearing

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10M 169/00 C10M 169/00 // C10N 10:02 C10N 10:02 20:02 20:02 30:06 30:06 30:08 30:08 30:12 30:12 40:02 40:02 50:10 50:10 F Term (reference) 3J101 AA02 AA32 AA42 AA52 AA62 EA52 EA63 FA06 FA33 GA13 GA16 GA29 4H104 CD02B CD04A DA02A EA02A EB02 FA01 FA02 LA03 LA04 LA06 PA01 QA18

Claims (4)

[Claims] 1. A rolling bearing for an electromagnetic clutch, a compressor, and an idler pulley, wherein a plurality of rolling elements are rotatably held between an inner ring and an outer ring, and grease is sealed in the rolling bearing. For an electromagnetic clutch, which is a mixed grease of a fluorine-based grease that uses polyether oil as a base oil and polytetrafluoroethylene as a thickener, and a grease other than a fluorine-based grease,
Rolling bearings for compressors and idler pulleys. 2. In the mixed grease, the grease other than the fluorine-based grease is at least one of a metal complex soap-based grease and a urea-based grease, and at least one of the metal complex soap-based grease and the urea-based grease: fluorine-based grease = 30 to 80: 2. The electromagnetic clutch according to claim 1, wherein the mixing ratio (mass ratio) is 70 to 20, and the total amount of the thickener is contained in a proportion of 15 to 35% by mass of the total amount of the mixed grease. Rolling bearings for compressors and idler pulleys. 3. Perfluoroether oil at 40 ° C.
Kinematic viscosity is 20 mm ²/ S to 400 mm²/ S, or
At 40 ° C, the base oil of greases other than fluorine-based grease
Kinematic viscosity of 10 mm²/ ~ 400 mm²/ S
An electromagnetic clutch according to claim 1 or 2,
Rolling bearings for compressors and idler pulleys. 4. The mixed grease according to claim 1, wherein the mixed grease contains an additive in a proportion of 20% by mass or less based on a total amount of the mixed grease. And rolling bearings for idler pulleys.