JP2003343584A - Roller bearing for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller bearing for a motor, particularly an automobile motor having excellent acoustic characteristics in a wide temperature range from a low temperature to a high temperature and an excellent high-temperature durability. <P>SOLUTION: The roller bearing for the motor comprises a plurality of rolling elements 5 rotatably held by a retainer 7 between an inner race 2 and an outer race 4, and a grease obtained by mixing a base oil having a kinematic viscosity at 40°C of 80 to 20 mm<SP>2</SP>/s and containing an ester synthetic oil as an indispensable component, with lithium soap. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing for a motor containing grease. In particular, the present invention relates to a starter motor, an electric power steering motor, a tilt motor for steering adjustment, a blower motor, a wiper motor and a bearing for a motor for a parade dow motor of an automobile, and more particularly to a rolling bearing for a motor exhibiting excellent acoustic characteristics from a low temperature to a high temperature.

[0002]

2. Description of the Related Art In various rolling bearings for automobile motors as described above, grease is mainly used for lubrication. Since these rolling bearings for automobile motors operate even at low temperatures, abnormal noise occurs due to poor lubrication at low temperatures, and because they are often placed near the driver's seat, they have acoustic characteristics (especially quietness). There are strict requirements for it. Further, some electric power steering motors, blower motors, etc. are used at high temperatures exceeding 100 ° C., and thus durability at high temperatures is also required.

Conventionally, as grease to be filled in the above-mentioned rolling bearings for automobile motors, lithium soap grease containing low viscosity ester synthetic oil mixed with lithium soap, or urea grease containing synthetic hydrocarbon oil mixed with urea compound. Is common. However, although the lithium soap type grease has good acoustic characteristics, it has a problem in high temperature durability and is not suitable for use at a high temperature exceeding 100 ° C. On the other hand, although urea-based grease has excellent high-temperature durability, it is inferior in acoustic characteristics to lithium soap grease and is difficult to use in locations where quietness is required.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and is for a motor having excellent acoustic characteristics in a wide temperature range from low temperature to high temperature and excellent in high temperature durability, particularly An object of the present invention is to provide a rolling bearing for an automobile motor.

[0005]

The object of the present invention is to rotatably hold a plurality of rolling elements by a cage between the inner ring and the outer ring of the present invention, and the kinematic viscosity at 40.degree.
This is achieved by a rolling bearing for a motor, characterized in that a base oil containing 200 mm ² / sec of an ester synthetic oil as an essential component is filled with grease containing lithium soap.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below in detail with reference to the drawings.

In the present invention, the bearing structure itself is not particularly limited, and it has been conventionally used for a starter motor, an electric power steering motor, a steering adjusting tilt motor, a blower motor, a wiper motor, a paraffin motor, etc. of an automobile. It can be a rolling bearing. For example, as shown in a sectional view in FIG. 1, an inner ring 2 having an inner ring raceway 1 on an outer peripheral surface and an outer ring raceway 3 on an inner peripheral surface.
A ball bearing in which a plurality of balls 5, which are rolling elements, are rotatably held by a cage 7 and further sealed with grease (not shown) described later by a sealing device 6 between the outer ring 4 and the outer ring 4. It can be illustrated. The enclosed grease will be described below.

[Base oil] The base oil used has a kinematic viscosity at 40 ° C. of 80 to 200 mm ² / sec, preferably 9
It is 0 to 150 mm ² / sec and contains an ester synthetic oil as an essential component. Kinematic viscosity is 80 mm ² / sec
If it is less than the above range, the fluidity at low temperatures tends to be poor, and abnormal noise tends to occur. Also, the kinematic viscosity is 200 mm ² /
When it is larger than sec, it becomes difficult to form an oil film at high temperature and seizure easily occurs.

The content of the ester synthetic oil in the base oil is preferably 30% by mass or more, especially 50% by mass or more, based on the total amount of the base oil, and if it is less than 30% by mass, the acoustic characteristics become poor. Besides the ester synthetic oil, synthetic hydrocarbon oil and ether synthetic oil can be preferably used. less than,
Examples of particularly preferable ester synthetic oils, synthetic hydrocarbon oils, and ether synthetic oils are shown, but the invention is not limited thereto.

Examples of the ester synthetic oil include dibutyl sebacate, di-2-ethylhexyl sebacate,
Diester oils such as dioctyl adipate, diisodecyl adipate, ditridecyl adipate, ditridecyl glutarate, methyl acetyl cinnolate, or aromatic ester oils such as trioctyl trimellitate, tridecyl trimellitate, tetraoctyl pyromellitate, Furthermore, polyol ester oils such as trimethylolpropane caprylate, trimethylolpropane pelargonate, pentaerythritol-2-ethylhexanoate, and pentaerythritol pelargonate, and also polyhydric alcohols and dibasic / monobasic acid mixtures. Examples thereof include complex esters which are oligoesters with aliphatic compounds.

Examples of the synthetic hydrocarbon oil include poly-α-olefins such as normal paraffin, isoparaffin, polybutene, polyisobutylene, 1-decene oligomer, 1-decene / ethylene cooligomer, or hydrides thereof, or monoalkylbenzene. , Alkylbenzene such as dialkylbenzene, and alkylnaphthalene such as monoalkylnaphthalene, dialkylnaphthalene, and polyalkylnaphthalene.

Examples of ether synthetic oils include polyglycol oils such as polyethylene glycol, polypropylene glycol, polyethylene glycol monoether, polypropylene glycol monoether, monoalkyl triphenyl ethers, alkyl diphenyl ethers, dialkyl diphenyl ethers, pentaphenyl ethers. Examples thereof include phenyl ether oils such as tetraphenyl ether, monoalkyl tetraphenyl ether and dialkyl tetraphenyl ether.

The base oil contains an ester synthetic oil as an essential component, and a synthetic hydrocarbon oil or an ether synthetic oil is appropriately used in combination to adjust the kinematic viscosity to the above range. Further, the base oil may be a single ester synthetic oil by mixing ester synthetic oils within the above range of kinematic viscosity.

[Thickener] The thickener blended in the above base oil is lithium soap. Of these, lithium stearate and lithium 12-hydroxystearate are preferable. In the present invention, in order to obtain desired acoustic characteristics and high temperature durability, the grease has a workability of N.
LGI No. 1-No. The range of 3 is preferable, and for that purpose, it is preferable to add lithium soap in a proportion of 5 to 20 mass% of the total amount of grease.

[Additives] Known additives may be added to the grease, if necessary, in order to impart more excellent performance. For example, metal soap other than lithium soap,
Benton, silica gel, and other gelling agents; amine-based, phenol-based, sulfur-based, zinc dithiophosphate, and other antioxidants;
Extreme pressure agents such as chlorine-based, sulfur-based, phosphorus-based, zinc dithiophosphate, organic molybdenum; oily agents such as fatty acids and animal and vegetable oils; rust inhibitors such as petroleum sulfonate, dinonylnaphthalene sulfonate, sorbitan ester; benzotriazole, Metal deactivators such as sodium nitrite; viscosity index improvers such as polymethacrylate, polyisobutylene, polystyrene and the like can be added alone or in appropriate combination. The addition amount is not particularly limited as long as the object of the present invention can be achieved, but the amount is 20% by mass or less of the total amount of grease. If the amount is larger than the above range, the contents of the base oil and the thickener are relatively decreased, so that the intended acoustic characteristics and high temperature durability cannot be obtained.

[Production Method] The method for producing the grease is not particularly limited, but it can be generally obtained by reacting lithium soap in a base oil. Manufacturing conditions such as heating temperature and stirring / mixing time at that time are appropriately set depending on the type and blending of the base oil, lithium soap, and additive used.

[0017]

EXAMPLES The present invention will be further described below with reference to examples.

(Preparation of grease) With the composition shown in Table 1,
Greases A to D were prepared. Incidentally, lithium 12-hydroxystearate was used as lithium soap, a diurea compound was used as a urea compound, a mixed oil of pentaerythritol ester and dipentaerythritol ester was used as an ester synthetic oil, and a poly-α-olefin oil was used as a synthetic hydrocarbon oil. . The grease A was prepared by changing the kinematic viscosity of the base oil in the range of 25 to 250 mm ² / sec and the grease C in the range of 3 to 25% by mass of the thickener. Grease D is for comparison in which the thickener is a urea compound.

[0019]

[Table 1]

(Bearing Acoustic Durability Test) A bearing acoustic durability test was conducted using the test apparatus 10 shown in FIG. In this test apparatus 10, a plurality of test bearings 20 are mounted on a rotary shaft 11 and housed in a housing 12, elastically supported by a disc spring 13, and a motor 14 rotates the rotary shaft 11 at a predetermined rotational speed. It is composed. Incidentally, the illustrated test apparatus 1
In No. 0, three rotary shafts 11 are provided, and each rotary shaft 11 is connected to a pulley 17 driven by a motor 14 via a joint 15 and is configured to rotate simultaneously. Reference numeral 16 is a support bearing.

The test bearing 20 has an inner diameter of 6 mm and an outer diameter of 1
5mm wide, 5mm wide, small diameter deep groove ball bearing with non-contact metal plate filled with 50mg of grease, ambient temperature 1
The Anderon value (vibration speed of 1800 to 10000 Hz) after continuous rotation for 2000 hours at 20 ° C., inner ring rotation speed of 3600 min ⁻¹ , and axial load of 19.6 N was measured. The grease A and the grease D shown in Table 1 were used as the enclosed grease, and the change in the Anderon value due to the difference in the base oil kinematic viscosity was determined. The results are shown in Fig. 3. The measured value was an average value of 16 test bearings, and a value of 3 anderon or less was passed.

(Bearing cage sound measurement) A test bearing in which 0.7 g of grease was enclosed in a deep groove ball bearing with an inner diameter of 15 mm, an outer diameter of 35 mm and a width of 11 mm and a non-contact rubber seal was used, and the bearing temperature was 0 ° C. and the inner ring rotational speed was 1800 min ^−1. , Was rotated with an axial load of 39.2 N, and the cage sound was measured using a frequency analyzer. The grease A and the grease D shown in Table 1 were used as the enclosed grease, and the change in the cage noise due to the difference in the base oil kinematic viscosity was determined. The results are shown in FIG. 3 according to the following evaluation points. No cage sound is generated: 1 Some cage noise is generated: 2
Cage size: 3

As shown in FIG. 3, the test bearing filled with grease A had a kinematic viscosity of 80 mm ² / sec (40 ° C.).
If the base oil of less than 3 exceeds the acceptance standard of 3 Anderon, but the base oil having a kinematic viscosity of 80 mm ² / sec (40 ° C.) or more can suppress the Anderon value to 3 Anderon or less, and a kinematic viscosity of 200 mm. ² / sec (4
Good results are shown up to 0 ° C. Also, with respect to the cage sound, good results can be obtained by using a base oil having a kinematic viscosity of 200 mm ² / sec (40 ° C.) or less. From this, the kinematic viscosity of the base oil used at 40 ° C. is 80 to 20
0 mm ² / sec, in particular it can be seen that it is preferable to 90~150mm ² / sec.

(Amount of Ester Synthetic Oil in Base Oil) Using the test apparatus 10 shown in FIG. 2, as a test bearing 20, a small diameter deep groove ball bearing with an inner diameter of 6 mm, an outer diameter of 15 mm and a width of 5 mm is provided. , Grease B shown in Table 1
Using 0 mg sealed, atmospheric temperature 120 ° C, inner ring rotation speed 3600min ^-1 , axial load 19.6N
Anderon value (18
The vibration speed of 00 to 10000 Hz) was measured.

The results are shown in FIG. 4, and it can be seen that good acoustic characteristics can be obtained by mixing 30% by mass or more of the ester synthetic oil in the base oil.

(Amount of Lithium Soap in Grease) Using the test apparatus 10 shown in FIG. 2, as a test bearing 20, a small-diameter deep groove ball bearing with an inner diameter of 6 mm, an outer diameter of 15 mm and a width of 5 mm was prepared. Grease C shown in 5
Using 0 mg sealed, atmospheric temperature 120 ° C, inner ring rotation speed 3600min ^-1 , axial load 19.6N
Anderon value (18
The vibration speed of 00 to 10000 Hz) was measured.

The results are shown in FIG. 5. By adding 5% by mass or more and 20% by mass of lithium soap to the grease,
It can be seen that good acoustic characteristics can be obtained.

[0028]

As described above, according to the present invention,
A rolling bearing for a motor, which is excellent in acoustic characteristics in a wide temperature range from low temperature to high temperature and excellent in high temperature durability, and particularly suitable for an automobile motor is provided.

[Brief description of drawings]

FIG. 1 is an example of a rolling bearing for a motor of the present invention (ball bearing).
FIG.

FIG. 2 is a schematic cross-sectional view showing the configuration of a bearing acoustic durability test apparatus used in an example.

FIG. 3 Kinematic viscosity (40 ° C.) of base oil obtained in Example
3 is a graph showing the relationship between the anderon value and the cage sound.

FIG. 4 is a graph showing the relationship between the compounding ratio of the ester synthetic oil in the base oil and the Anderon value obtained in the examples.

FIG. 5 is a graph showing the relationship between the content of lithium soap in grease and the Anderon value obtained in the examples.

[Explanation of symbols]

2 inner ring 4 outer ring 5 rolling elements 6 Sealing device 7 cage 10 Bearing acoustic durability tester 20 Test bearing

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // C10N 10:02 C10N 10:02 20:02 20:02 30:00 30:00 Z 30:08 30 : 08 40:02 40:02 50:10 50:10 (72) Inventor Kenji Okuma 1-5-50 Kumeinuma Kugenuma, Fujisawa City, Kanagawa Prefecture F-Term (reference) 3J101 AA01 AA32 AA42 AA52 AA62 CA12 CA32 EA64 FA01 FA06 GA01 GA24 4H104 BA04A BB14B BB19B BB32A BB33A BB34A BB36A BB43A CA01A EA02A FA01 LA04 LA20 PA01 QA18

Claims (3)

[Claims] 1. A plurality of rolling elements are rotatably held by a retainer between an inner ring and an outer ring, the kinematic viscosity at 40 ° C. is 80 to 200 mm ² / sec, and an ester synthetic oil is an essential component. A rolling bearing for a motor, characterized in that grease containing lithium soap is filled in the base oil. 2. The rolling bearing for a motor according to claim 1, wherein the grease contains at least 30 mass% of an ester synthetic oil based on the total amount of the base oil. 3. The rolling bearing for a motor according to claim 1, wherein the grease contains 5 to 20% by mass of lithium soap in the total amount of the grease.