JP2009191173A - Grease composition and rolling device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grease composition that is excellent in heat resistance, rust-preventive properties and wear resistance, includes low torque over a wide temperature range from a low temperature to a high temperature and is also excellent in torque stability, and to provide a rolling device that is excellent in durability at a high temperature, rust-preventive properties and wear resistance, includes low torque over a wide temperature range from a low temperature to a high temperature and is also excellent in torque stability. <P>SOLUTION: A deep groove ball bearing is equipped with an inner ring 1 having a raceway surface 1a, an outer ring 2 having a raceway surface 2a opposed to the raceway surface 1a, a rolling element 3 rollably arranged between the raceway surfaces 1a and 2a and a cage 4 for holding the rolling element 3 between the inner ring 1 and the outer ring 2. A grease composition G for lubricating the deep groove ball bearing is sealed in the internal space formed between the inner ring 1 and the outer ring 2. The grease composition G includes a fluorine oil, a fluororesin and calcium carbonate having a primary particle size of not more than 100 nm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a grease composition. The present invention also relates to a rolling device such as a rolling bearing, a ball screw, a linear guide device, and a linear motion bearing.

  In recent years, automobiles (passenger cars) have been required to be reduced in size and weight and expanded in living space, and therefore, the engine room space has been reduced, and various parts (for example, electric fan motors) arranged in the engine room have been forced to be reduced. , Electrical components such as fluid couplings for cooling fans and powder clutches, and engine accessories such as alternators and intermediate pulleys) are being further reduced in size and weight. Since performance (for example, output) decreases due to the reduction in size and weight, the amount is dealt with by increasing the speed. In addition to this, since the improvement of silence is desired and the engine room is being sealed, the temperature increase in the engine room is promoted. Therefore, the various parts have been required to have a property to withstand high temperatures.

  In addition, in the case of the various parts described above, motor control motor bearings such as electronic control throttle bearings, idle rotation control valve (ISCV) bearings, exhaust gas recirculation device (EGR) bearings, etc. Similarly, high speed due to downsizing of rolling bearings and high temperature due to sealing of the engine room are problems. In addition, low torque is required for energy loss reduction and operability in a low temperature environment of −30 ° C. or lower, and the ability to quickly stabilize torque is also required (hereinafter, this Such torque performance is referred to as torque stability performance).

The same applies to rolling bearings used in office automation equipment (OA equipment) such as hard disk drives (HDD), laser beam printers (LBP), and copiers. Lower durability and lower torque performance are required.
For these reasons, a grease composition using an ether oil-based lubricating oil that is superior in heat resistance and torque performance at low temperatures as a base oil is generally used for lubricating rolling bearings for various applications as described above. in use. In particular, a grease composition using a silicone oil-based or fluorine oil-based lubricating oil having higher heat resistance as a base oil is used for a portion exposed to a high temperature of 160 ° C. or higher.

By the way, in a rolling bearing in which a grease composition is sealed, a seal or a shield is provided to prevent leakage of the grease composition to the outside and to prevent entry of foreign matter from the outside. However, a rolling bearing cannot be completely sealed even if it is provided with the above-described members. Therefore, it is inevitable that foreign matters enter from the outside.
These foreign substances entering from the outside include substances and moisture that are sources of rust. In addition, condensation may occur in the rolling bearing due to a rapid temperature change. For these reasons, it is indispensable that the grease composition used for the rolling bearing has rust prevention performance.

In order to impart rust prevention performance, a rust inhibitor is usually added to the grease composition. Various substances are known as rust preventives, and nitrite and organic sulfonic acid metal salts are widely used as those particularly excellent in rust prevention performance.
However, it is not preferable to use nitrite because amines which are carcinogenic substances may be generated when used at high temperatures. Moreover, even when using, the quantity may be restrict | limited and the rust prevention performance may not fully be exhibited.

  Moreover, a rust preventive agent expresses rust prevention property by forming a corrosion-resistant film on the metal surface. Therefore, in order to form a uniform anticorrosive film over the raceway surface of the rolling bearing and the entire rolling element, it is necessary for the rust inhibitor to dissolve in the base oil. However, since organic sulfonic acid metal salts are insoluble in silicone oil and fluorine oil-based lubricating oils having excellent heat resistance, organic sulfonic acid metal salts are not included in grease compositions based on these lubricating oils. It cannot be used as a rust inhibitor.

For this reason, grease compositions based on silicone oils and fluorine oils are addressed by adding fluorine compounds having functional groups such as carbonyl groups, alcohol groups and ester groups in the skeleton. However, it is difficult to say that these fluorine compounds have low rust prevention performance and can withstand practical use.
Against this background, it is proposed to add a vaporizable rust inhibitor and a magnesium compound to a grease composition based on silicone oil and fluorine oil, and to improve rust prevention performance by synergistic effects of both. (See Patent Document 1).
JP 2004-176075 A JP 2007-154084 A JP-A-10-184706 JP 2000-273478 A

However, in the grease composition described in Patent Document 1, powders such as magnesium oxide are used as the magnesium compound, but since these are hard materials, the surface of the constituent members of the rolling device is worn away. There was a risk of causing rusting.
Further, low torque is required to reduce energy loss and ensure operability in a low temperature environment of −30 ° C. or lower, and torque stability is also required. However, there is room for improvement in these respects. was there.

  Therefore, the present invention solves the problems of the prior art as described above, is excellent in heat resistance, rust prevention, and wear resistance, and has low torque and stable torque over a wide temperature range from low temperature to high temperature. It is an object to provide a grease composition having excellent performance. In addition, the present invention provides a rolling device that is excellent in durability at high temperatures, rust prevention, and wear resistance, has low torque over a wide temperature range from low temperature to high temperature, and has excellent torque stability performance. Together, it is an issue.

In order to solve the above problems, the present invention has the following configuration. That is, the grease composition of claim 1 according to the present invention contains fluorine oil, a fluororesin, and metal carbonate fine particles having a primary particle size of 100 nm or less, wherein the metal is an alkali metal or an alkaline earth metal. It is characterized by being at least one of.
Since the grease composition of the present invention is based on a fluorine oil such as perfluoropolyether oil having excellent thermal stability even at high temperatures, the base oil is hardly thermally deteriorated even at a high temperature environment of 160 ° C. or higher. Excellent heat resistance. In addition, since the grease composition can keep the base oil viscosity low, it has excellent low-temperature fluidity and low torque over a wide temperature range from low to high.

Furthermore, since it contains metal carbonate fine particles having a primary particle size of 100 nm or less, it is excellent in rust prevention and wear resistance. As the metal, alkali metals such as sodium and potassium, and alkaline earth metals such as magnesium, calcium, strontium and barium are preferable, but calcium is particularly preferable.
When the grease composition of the present invention is used in a rolling device, the metal carbonate fine particles enter the oil film formed between the rolling contact surfaces (between the raceway surface and the rolling surface of the rolling element), and are electrically Since the film is formed by adsorbing on the rolling contact surface due to the interaction, rusting on the rolling contact surface is suppressed. Moreover, since the direct contact between the rolling contact surfaces is prevented by the coating, generation of a new surface is suppressed, and wear resistance and seizure resistance are improved. Furthermore, the occurrence of premature delamination accompanied by a white structure change due to the penetration of hydrogen into the steel is suppressed. Since the metal carbonate fine particles having a primary particle size of 100 nm or less (preferably 50 nm or less) have a large specific surface area and a large number of particles per unit mass, a uniform film is easily formed on the rolling contact surface.

  A rolling device according to a second aspect of the present invention includes an inner member having a raceway surface on an outer surface, and a raceway surface facing the raceway surface of the inner member, and is disposed outward of the inner member. An outer member, a plurality of rolling elements arranged between the both raceway surfaces so as to freely roll, and a lubricant that lubricates between the raceway surfaces and the rolling surfaces of the rolling bodies. In the rolling device, the lubricant is the grease composition according to claim 1.

Such a rolling device of the present invention is provided with a grease composition containing metal carbonate fine particles having a primary particle size of 100 nm or less, and thus is excellent in durability at high temperatures, rust prevention, and wear resistance. In addition, the torque is low and the torque stability is excellent over a wide temperature range from low temperature to high temperature.
Furthermore, a rolling device according to a third aspect of the present invention is the rolling device according to the second aspect, wherein the rolling device is a rolling bearing incorporated in a motor of an electronic control unit used in an automobile.

  Rolling bearings with the above grease composition have excellent durability at high temperatures, rust prevention, and wear resistance, as well as low torque and excellent torque stability over a wide temperature range from low to high temperatures. Yes. Therefore, it is suitable as a rolling bearing incorporated in a motor of an electronic control device of an automobile such as an electronic control throttle, an idle rotation control valve, and an exhaust gas recirculation device.

Furthermore, the rolling device according to a fourth aspect of the present invention is the rolling device according to the second aspect, wherein the rolling device is a rolling bearing incorporated in an electrical component of an automobile or an engine accessory of the automobile.
Rolling bearings with the above grease composition have excellent durability at high temperatures, rust prevention, and wear resistance, as well as low torque and excellent torque stability over a wide temperature range from low to high temperatures. Yes. Therefore, it is suitable as a rolling bearing incorporated into, for example, an electrical component of an automobile or an engine accessory. Examples of the electrical components include an electric fan motor, a fluid coupling for a cooling fan, and a powder clutch. Examples of the engine accessory include an alternator and an intermediate pulley.

The present invention can be applied to various rolling devices. For example, a rolling bearing, a ball screw, a linear guide device, a linear motion bearing, and the like.
In the present invention, the inner member means an inner ring when the rolling device is a rolling bearing, a screw shaft when the ball screw is also used, a guide rail when the linear guide device is used, and a linear bearing device. Each axis means. The outer member is the outer ring when the rolling device is a rolling bearing, the nut when it is a ball screw, the slider when it is a linear guide device, and the outer cylinder when it is also a linear bearing. Each means.

  The grease composition of the present invention is excellent in heat resistance, rust resistance, and wear resistance, has low torque over a wide temperature range from low temperature to high temperature, and is excellent in torque stability performance. The rolling device of the present invention is excellent in durability at high temperatures, rust prevention, and wear resistance, and has low torque over a wide temperature range from low temperature to high temperature, and excellent torque stability.

DESCRIPTION OF EMBODIMENTS Embodiments of a grease composition and a rolling device according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a structure of a deep groove ball bearing which is an embodiment of a rolling device according to the present invention. This deep groove ball bearing has an inner ring 1 having a raceway surface 1a on the outer peripheral surface, an outer ring 2 having a raceway surface 2a facing the raceway surface 1a on the inner peripheral surface, and a raceway between the raceway surfaces 1a and 2a. A plurality of rolling elements (balls) 3, a cage 4 that holds the plurality of rolling elements 3 between the inner ring 1 and the outer ring 2, and a sealing device 5 that covers an opening of a gap between the inner ring 1 and the outer ring 2 5 (for example, a contact type rubber seal or a shield). Note that the cage 4 and the sealing device 5 may not be provided.

  Grease that lubricates between the raceway surfaces 1a and 2a and the rolling surface 3a of the rolling element 3 in a gap (bearing space) formed between the inner ring 1 and the outer ring 2 and provided with the rolling element 3 therein. Composition G is arranged. The base oil of this grease composition G is fluoro oil, the thickener is fluoro resin, and metal carbonate fine particles having a primary particle size of 100 nm or less are added. As the metal of the metal carbonate fine particles, alkali metals such as sodium and potassium, and alkaline earth metals such as magnesium, calcium, strontium and barium are preferable, but calcium is particularly preferable.

  In such a deep groove ball bearing, since the grease composition G contains metal carbonate fine particles having a primary particle size of 100 nm or less, compared to the case of using a conventional fluorine grease that does not contain metal carbonate fine particles. Excellent torque stability. Moreover, it is excellent in rust prevention and abrasion resistance. Furthermore, the heat resistance in a high temperature environment of 160 ° C. or higher and the low torque property over a wide temperature range from low temperature to high temperature have excellent performance equivalent to or higher than that in the case of using conventional fluorine grease.

  Therefore, the deep groove ball bearing of this embodiment is suitable as a rolling bearing (for example, an electronic control throttle bearing, an ISCV bearing, or an EGR bearing) incorporated in a motor of an electronic control device used in an automobile. Further, it is suitable as a rolling bearing incorporated in an electric component of an automobile (for example, an electric fan motor, a fluid coupling for a cooling fan, a powder clutch) or an engine auxiliary machine (for example, an alternator, an intermediate pulley) of the automobile.

Below, each component which comprises the grease composition G is demonstrated in detail.
[About metal carbonate fine particles]
The content of the metal carbonate fine particles in the grease composition G is not particularly limited, but is preferably 0.01% by mass or more and 10% by mass or less of the entire grease composition G. If the content of the metal carbonate fine particles is less than 0.01% by mass, sufficient rust prevention properties may not be obtained. On the other hand, if it exceeds 10% by mass, the metal carbonate fine particles tend to aggregate in the grease composition, which may adversely affect wear resistance and seizure resistance. In order to make such a problem less likely to occur, the content of the metal carbonate fine particles is more preferably 0.1% by mass or more and 5% by mass or less of the entire grease composition G.

A vaporizable rust inhibitor such as benzotriazole may be used in combination with the metal carbonate fine particles.
The metal carbonate fine particles are preferably subjected to a surface treatment with an organic substance having a polar group. When the surface treatment is performed, the adsorptivity of the metal carbonate fine particles to the raceway surfaces 1a and 2a and the rolling surface 3a is improved, so that a rust preventive film is formed favorably. Examples of the organic substance having a polar group include fatty acids, ammonium salts, and rosin acid.

[About fluororesin]
The type of the fluororesin that is a thickener is not particularly limited, but polytetrafluoroethylene (PTFE), tetrafluoroethylene and other ethylenically unsaturated hydrocarbon monomers partially or fluorinated These copolymers are preferred.
When producing the grease composition, the base oil and the fluororesin powder may be mixed, or the base oil and the fluororesin suspension may be mixed.

[About base oil]
Although the kind of fluorine oil used as the base oil of the grease composition G is not particularly limited, a fluoropolyether oil such as perfluoropolyether oil (PFPE) is preferable. Fluoropolyether oil includes linear and branched ones, either one of which may be used, or a mixture of both. The kinematic viscosity of the base oil is not particularly limited, and those having a general kinematic viscosity as the base oil of the grease composition can be used without any problem.

However, a rolling bearing incorporated in a motor of an electronic control device used in an automobile is particularly required to have excellent durability in a high temperature environment of 160 ° C. or higher. Further, low torque is particularly required for reduction of energy loss and sufficient operability in a low temperature environment of −30 ° C. or lower.
Therefore, it is preferable to use a grease composition based on linear fluoropolyether oil as a lubricant for rolling bearings for such applications. Since the linear fluoropolyether oil has a high viscosity index and the change in viscosity with temperature is small, the rolling bearing can have a low torque over a wide temperature range.

In addition, in the case of rolling bearings for such applications, in order to suppress the generation of noise at low temperature startup due to insufficient low temperature fluidity of the grease composition and seizure that occurs due to the difficulty of forming an oil film at high temperatures, kinematic viscosity at 40 ° C. oil is preferably 20~400mm ² / s, more preferably from 30 to 200 mm ² / s, further preferably 60~120mm ² / s.

On the other hand, in the case of a rolling bearing incorporated in an automobile electrical component or an automobile engine accessory, it is preferable to use a grease composition based on a branched-chain fluoropolyether oil as a lubricant. Kinematic viscosity at 40 ° C. of the base oil is preferably 10~400mm ² / s, more preferably 15~270mm ² / s, further preferably 40~180mm ² / s.
[Additives]
To the grease composition G, an additive generally used in the grease composition may be added together with the metal carbonate fine particles. For example, antioxidants, rust inhibitors, metal deactivators, oiliness agents, antiwear agents, extreme pressure agents and the like can be mentioned. These additives may be used independently and may be used in combination of 2 or more types as appropriate.

  In addition, this embodiment shows an example of this invention and this invention is not limited to this embodiment. For example, in the present embodiment, a deep groove ball bearing has been described as an example of a rolling device, but the present invention can be applied to various types of rolling bearings. For example, radial type rolling bearings such as angular contact ball bearings, self-aligning ball bearings, cylindrical roller bearings, tapered roller bearings, needle roller bearings, and self-aligning roller bearings, and thrust types such as thrust ball bearings and thrust roller bearings This is a rolling bearing. Furthermore, the present invention can be applied not only to rolling bearings but also to various types of various rolling devices. For example, a ball screw, a linear guide device, a linear motion bearing, or the like.

Hereinafter, the present invention will be described more specifically with reference to examples.
[Example A]
Nine types of grease compositions having the following compositions were prepared and evaluated for rust prevention and wear resistance.
First, the grease composition will be described. A base grease with a blending degree of 280 is prepared by blending PTFE suspension with a mixed oil (kinematic viscosity at 40 ° C is 400 mm ² / s) mixed with the same amount of linear PFPE and branched PFPE. (This is referred to as Comparative Example A).

  Metal carbonate fine particles were added to this base grease to obtain a grease composition of an example. The addition amount of the metal carbonate fine particles is 0.001, 0.01, 0.1, 0.5, 1, 5, 10, 15% by mass of the whole grease composition. Regardless of the amount added, the penetration of the grease composition was 280. The metal carbonate fine particles are calcium carbonate having a primary particle size of 30 nm (Viscoexcel-30 manufactured by Shiroishi Calcium Co., Ltd.).

Next, a method for evaluating rust prevention and wear resistance will be described.
[Rust prevention evaluation method]
These grease compositions (0.2 g) were sealed in a deep groove ball bearing (No. 608, inner diameter: 8 mm, outer diameter: 22 mm, width: 7 mm), 5 under the conditions of an axial load of 29.4 N, a rotational speed of 1800 min ⁻¹ , and an ambient temperature of room temperature. The grease composition was uniformly dispersed in the bearing by rotating for a minute. Next, this deep groove ball bearing was left in a constant temperature and humidity chamber adjusted to a temperature of 80 ° C. and a humidity of 90% RH for 200 hours and then disassembled, and the state of rust generated on the raceway surface of the inner ring was observed from a stereomicroscope. Observed (magnification rate is 5 times).
And according to the number of the dotted | punctate rust which generate | occur | produced, the generation | occurrence | production situation of rust was evaluated in the following five steps. That is, when the number of punctate rust generated is 0, it is “1”, when it is 1-5, it is “2”, when it is 6-10, it is “3”, and when it is 11-20, it is “4”. , 21 or more were designated as “5”. The results are shown in the graph of FIG. The occurrence of rust in Comparative Example A was “5”.

[Evaluation method for wear resistance]
Abrasion resistance was evaluated using a tester similar to the high-speed four-ball tester specified in ASTM D 2596. That is, three test balls (SUJ2 steel balls for ball bearings, 1/2 inch in diameter) are arranged and fixed in an equilateral triangle shape so as to contact each other, and one test is performed in a recess formed in the center thereof. A ball was placed. Then, after applying the grease composition to all the test balls, the loaded test ball was loaded at a constant speed (sliding speed of 0.38 m / s) for 1 hour under a load (surface pressure of 1.5 GPa). Rotated. After the rotation, the diameters of the wear marks generated on the three test balls arranged in an equilateral triangle were measured in the X direction and the Y direction, and the average value of these measured values was taken as the wear mark diameter.
The result is shown in the graph of FIG. In addition, the numerical value of the wear scar diameter of FIG. 2 is shown by the relative value when the wear scar diameter of Comparative Example A to which calcium carbonate is not added is 1.

[Example B]
Four types of grease compositions having the following compositions were prepared and evaluated for rust prevention and wear resistance.
Various calcium carbonates having different primary particle diameters were added to the base grease of Example A (Comparative Example A) to obtain grease compositions of Examples. The primary particle size of calcium carbonate is 30 nm, 50 nm, 100 nm, and 150 nm. These calcium carbonates are all manufactured by Shiroishi Calcium Co., Ltd., and are Viscoexcel-30, Hakujyo Hana CC, Vigot 10 and Vigot 15, respectively. In either case, the amount of calcium carbonate added was 0.1% by mass of the entire grease composition, and the grease composition was prepared so that the penetration of the grease composition was 280.
The antirust property and wear resistance of these grease compositions were evaluated by the same method as in Example A. The results are shown in the graph of FIG.

[Example C]
Three types of grease compositions having the following compositions were prepared and evaluated for rust prevention and wear resistance.
To the base grease of Example A (Comparative Example A), calcium carbonate subjected to surface treatment using a different surface treatment agent was added to obtain a grease composition of Example. The surface treatment is one using a fatty acid as the surface treatment agent, one using rosin acid as the surface treatment agent, and no surface treatment.

All of these surface-treated calcium carbonates are manufactured by Shiroishi Calcium Co., Ltd., and are White Glossy CCR, White Glossy T-DD, and White Glossy PZ, respectively. In either case, the primary particle diameter of calcium carbonate was 80 nm, the addition amount was 0.5% by mass of the entire grease composition, and the grease composition was prepared so that the penetration of the grease composition was 280.
The antirust property and wear resistance of these grease compositions were evaluated by the same method as in Example A. The results are shown in the graph of FIG.

Example D
Nine types of grease compositions having the following compositions were prepared and evaluated for rust prevention and torque performance.
First, the grease composition will be described. A base grease having a blending degree of 280 was prepared by blending PTFE powder with linear PFPE (viscosity index is 286) having a kinematic viscosity at 40 ° C. of 90 mm ² / s (this is a comparative example) B).

  To this base grease, calcium carbonate having a primary particle size of 30 nm (Viscoexcel-30 manufactured by Shiraishi Calcium Co., Ltd.) was added to obtain a grease composition of an example. The amount of calcium carbonate added is 0.001, 0.01, 0.1, 0.5, 1, 5, 10, 15% by mass of the entire grease composition. Regardless of the amount added, the penetration of the grease composition was 280.

Next, a method for evaluating rust prevention and torque performance will be described. The evaluation method of rust prevention is the same as in Example A. The results are shown in the graph of FIG. The occurrence of rust in Comparative Example B was “5”.
[Evaluation method for torque performance at room temperature]
A deep groove ball bearing having an inner diameter of 8 mm, an outer diameter of 22 mm, and a width of 7 mm is filled with 0.2 g of a grease composition and rotated under the conditions of an inner ring rotational speed of 1800 min ⁻¹ , an ambient temperature of 30 ° C., a radial load of 0 N, and an axial load of 29.4 N. It was. Then, the time required to reach an intermediate value between the initial torque value and the steady torque value (hereinafter referred to as torque half-life) was measured, and the torque stability performance was evaluated based on the torque half-life.
The result is shown in the graph of FIG. In addition, the numerical value of the torque half life of FIG. 6 is shown by the relative value when the torque half life of the comparative example B which does not add calcium carbonate is set to 1.

[Evaluation method for torque performance at low temperatures]
Enclose the same amount of grease composition in the same deep groove ball bearing as the torque performance evaluation method described above at normal temperature, and rotate the deep groove ball bearing under the same conditions except that the ambient temperature is -40 ° C. The initial torque value (low temperature torque) was measured.
The results are shown in the graph of FIG. The low temperature torque in this graph is shown as a relative value when the low temperature torque of the grease of Comparative Example B is 1.

Example E
Nine types of grease compositions having the following compositions were prepared, and their rust prevention and seizure resistance were evaluated.
First, the grease composition will be described. PTFE powder was blended with branched PFPE having a kinematic viscosity at 40 ° C. of 60 mm ² / s to prepare a base grease having a blending degree of 280 (this is referred to as Comparative Example C).

  To this base grease, calcium carbonate having a primary particle size of 30 nm (Viscoexcel-30 manufactured by Shiraishi Calcium Co., Ltd.) was added to obtain a grease composition of an example. The amount of calcium carbonate added is 0.001, 0.01, 0.1, 0.5, 1, 5, 10, 15% by mass of the entire grease composition. Regardless of the amount added, the penetration of the grease composition was 280.

Next, a method for evaluating rust prevention and seizure resistance will be described. The evaluation method of rust prevention is the same as in Example A. The results are shown in the graph of FIG. The occurrence of rust in Comparative Example C was “5”.
[About seizure resistance at high temperatures]
A grease composition was sealed in a deep groove ball bearing with a contact type rubber seal having an inner diameter of 17 mm, an outer diameter of 47 mm, and a width of 14 mm, and rotated under the conditions of an inner ring rotational speed of 17000 min ⁻¹ , a bearing outer ring temperature of 200 ° C., and a radial load of 4900 N. When the bearing outer ring temperature rose to 220 ° C. or higher, it was judged that seizure had occurred, and the time until that time was measured. Four tests were conducted for one type of grease composition, and the average value was defined as the seizure life of the bearing. Note that the amount of the grease composition enclosed is 30% by volume of the bearing space volume.
The results are shown in the graph of FIG. The seizure life in this graph is shown as a relative value when the seizure life of the grease composition of Comparative Example C is 1.

It is a longitudinal cross-sectional view which shows the structure of the deep groove ball bearing which is one Embodiment of the rolling device which concerns on this invention. It is a graph which shows the correlation with the addition amount of calcium carbonate, the generation | occurrence | production state of rust, and abrasion resistance. It is a graph which shows the correlation with the primary particle size of calcium carbonate, the generation | occurrence | production state of rust, and abrasion resistance. It is a graph which shows the correlation with the surface treatment method of calcium carbonate, the generation | occurrence | production state of rust, and abrasion resistance. It is a graph which shows the correlation with the addition amount of calcium carbonate, and the generation | occurrence | production state of rust. It is a graph which shows the correlation with the addition amount of calcium carbonate, and torque performance. It is a graph which shows the correlation with the addition amount of calcium carbonate, and the generation | occurrence | production state of rust. It is a graph which shows the correlation with the addition amount of calcium carbonate, and a seizure lifetime.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inner ring 1a Raceway surface 2 Outer ring 2a Raceway surface 3 Rolling element 3a Rolling surface G Grease

Claims (4)

  A grease composition comprising fluorine oil, a fluororesin, and metal carbonate fine particles having a primary particle size of 100 nm or less, wherein the metal is at least one of an alkali metal and an alkaline earth metal.   An inner member having a raceway surface on the outer surface, an outer member having a raceway surface opposite to the raceway surface of the inner member, and arranged on the outer side of the inner member, and rolling between the both raceway surfaces The rolling device comprising: a plurality of freely arranged rolling elements; and a lubricant that performs lubrication between the raceway surface and the rolling surface of the rolling element. A rolling device characterized by having a grease composition.   The rolling device according to claim 2, wherein the rolling device is a rolling bearing incorporated in a motor of an electronic control device used in an automobile.   The rolling device according to claim 2, wherein the rolling device is a rolling bearing incorporated in an electrical component of an automobile or an engine auxiliary machine of the automobile.

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