JP2003301188A - Lubricating grease and bearing using the lubricating grease - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating grease which adds little load to the environment if it is eluted into water. <P>SOLUTION: The lubricating grease contains a base oil being polyoxypropylene glyceryl ether and a density controlling powder. The grease contains a thickener which is lithium soap but may be something else. Because the grease contains the base oil being polyoxypropylene glyceryl ether, it sparingly dispersed in water and reduces the formation of an oil film. The contained density controlling powder can control the floating and sinking of the grease to or in water and facilitates its recovery or other treatments. <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 lubricating grease, and more particularly to a lubricating grease used in bearings used in water.

[0002]

2. Description of the Related Art Lubricating grease uses lubricating oil as a base oil.
It is a semi-solid or solid product in which a thickener is dispersed in lubricating oil. Generally, a mineral oil is used as a base oil, but when it is used for a special purpose, a synthetic oil may be used as a base oil.

As thickeners, soaps such as calcium soap and lithium soap, inorganic non-soaps such as silica gel, and organic non-soaps such as urea are used. Here, the structure of grease will be described by taking a typical soap thickener as an example. In the thickener, soap molecules form micelles and grow collectively to form soap fibers.
The fibers are entangled in a lubricating oil that is a base oil to form a network structure like a spongy body. Lubricating oil is retained in this mesh structure by an adsorption action and a capillary phenomenon. In this way, the grease is usually semi-solid or solid. When the grease receives an external pressure at the lubrication point, the fibers of the thickener are separated and softened to become fluid.

Further, an antioxidant, a corrosion inhibitor, a structure stabilizer, etc. may be added to the grease. A solid lubricant may be added to adjust the lubrication performance.

Such grease is used in bearings and the like. In a bearing used in water or soil, grease is injected under pressure to counteract the external pressure in order to prevent foreign matter and water from entering the bearing due to the external pressure. Therefore, some grease may leak from the gap between the bearing and the shaft.

[0006] In a grease using a mineral oil or a part of a synthetic oil, the oil content may separate and form an oil film when leaking into water. Further, since the density of general grease is not adjusted, a part of the separated grease becomes an oil film, a part floats, and a part sediments, which makes recovery difficult.

Water-soluble grease, which does not cause oil floating even if it leaks, is sometimes used. However, since water-soluble grease causes evaporation and separation of water, care must be taken in handling, and problems may occur in lubrication performance.

A grease which is less likely to separate when leaking into water, and particularly causes less oil film is desired. Further, a grease having a low separation when leaked into water and having a density adjusted so as to exhibit the property of either settling or floating in water is desired. Furthermore, an inexpensive grease that is easy to handle, has sufficient lubricating performance, and is inexpensive is desired.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a grease which is difficult to diffuse when it leaks into water. Another object of the present invention is to provide a grease having a density adjusted so as to exhibit a property of either settling or floating in water when leaked into water.

[0010]

One form of the grease of the present invention comprises polyoxyalkylene glyceryl ether. It is preferable that the polyoxyalkylene glyceryl ether contains a polymerization of oxyalkyl having 3 or more carbon atoms, since it is sparingly soluble in water in an average molecular weight range suitable for use as a base oil.

One form of lubricating grease of the present invention comprises polyoxypropylene glyceryl ether. Polyoxypropylene glyceryl ether is contained as a base oil of a lubricating grease, and is difficult to disperse when the lubricating grease leaks into water, and is preferable in that an oil film is not formed. Polyoxypropylene glyceryl ether is preferable because it has versatility, is inexpensive, and satisfies the lubricating performance. The polyoxypropylene glyceryl ether is preferably used as the base oil of the lubricating grease and has an average molecular weight of 1,000 to 10,000 from the viewpoint of viscosity, lubricity and water solubility. Considering the solubility in water, the average molecular weight is 30
A polyoxypropylene glyceryl ether of 00 is preferred.

One of the methods for producing the lubricating grease of the present invention has a step of causing a saponification reaction in polyoxyalkylene glyceryl ether to produce soap as a thickener.

One of the methods for producing the lubricating grease of the present invention is to carry out a saponification reaction in polyoxyalkylene glyceryl ether to produce soap as a thickener, and polyoxyalkylene glyceryl ether and soap. Heating the mixture to dissolve the soap, and then further adding polyoxyalkylene glyceryl ether.

The polyoxyalkylene glyceryl ether used in the method for producing the lubricating grease of the present invention is preferably polyoxypropylene glyceryl ether because of its versatility, low cost, and good lubricating performance. .

Lithium soap can be used as the soap used in the method for producing the lubricating grease of the present invention. In addition, it does not prevent the use of commonly used thickeners.

One form of the lubricating grease of the present invention contains a powder for adjusting the density. The density of the grease is adjusted so that it will float or settle when the lubricating oil leaks into the water, and it will be manufactured so that it can be collected easily.

The powder used for adjusting the density in the lubricating grease of the present invention is preferably a solid lubricant from the viewpoint of the lubricating performance of the lubricating grease.

More specifically, the powder used for adjusting the density in the lubricating grease of the present invention is calcium carbonate, zinc white, polytetrafluoroethylene (PTF).
E), molybdenum disulfide, organic molybdenum, MCA, tungsten disulfide, graphite, carbon fluoride, boron nitride, mica, zinc stearate, calcium stearate, aluminum stearate, polyethylene powder, or a mixture of two or more. Preferably there is.

The powder used for adjusting the density in the lubricating grease of the present invention is calcium carbonate,
Lubrication performance, price, and low toxicity are more preferable.

Further, one form of the lubricating grease of the present invention contains both powder for adjusting the density and polyoxyalkylene glyceryl ether. Furthermore, the fact that the polyoxyalkylene glyceryl ether is a polyoxypropylene glyceryl ether means that versatility, price,
It is preferable in terms of lubrication performance. Containing polyoxypropylene glyceryl ether and further containing powder for density adjustment makes it difficult to disperse in water, does not form an oil film, and controls floatation and sedimentation, making collection and processing easier. Is preferable because it can reduce the load on the environment.

In one of the methods for producing the lubricating grease of the present invention, powder is added to adjust the density.

One of the methods for producing a lubricating grease containing a powder and having a density adjusted according to the present invention is to perform a saponification reaction in a base oil to cause a saponification reaction to produce soap as a thickener. Heating the mixture of base oil and soap to dissolve the soap and then adding more base oil;
After step B, there is step C of adding powder.
The powder is preferably a solid lubricant in terms of lubricating performance. The fact that the powder is calcium carbonate means that the lubricating performance is
It is preferable because of its low price and low toxicity.

One form of the lubricating grease of the present invention comprises polyoxypropylene glyceryl ether, calcium carbonate and lithium soap.

A bearing using the lubricating grease of the present invention is
It is preferable because the leaked lubricating grease is less dispersed, is easy to collect or process, and can reduce the load on the environment. Since the grease of the present invention is difficult to disperse in seawater and water, the bearing of the present invention is preferable for use in seawater and water.

[0025]

The components of the lubricating grease according to the invention are described below. The lubricating grease of the present invention is a base oil,
Consists of thickener, powder, and necessary additives.

In the lubricating grease of the present invention, polyoxyalkylene glyceryl ether represented by the following chemical formula is used as a base oil.

[Chemical 1] The molecular weight of polyoxyalkylene glyceryl ether is
As the base oil of the lubricating oil or the lubricating grease, one having an appropriate viscosity is selected and used according to the consistency of the purpose. In a grease that is required to be water resistant or not dispersible in water, and in the range of an appropriate molecular weight of polyoxyalkylene glyceryl ether used for a lubricating oil, when m is 2 or less, the solubility in water is It is not preferable because it is large.

In particular, the fact that polyoxypropylene glyceryl ether represented by the following chemical formula is used as the polyoxyalkylene glyceryl ether, that the polyoxypropylene glyceryl ether has general versatility, that it satisfies the lubricating performance, and that the price is It is desirable because it is cheap. The polyoxyalkylene glyceryl ether used in the lubricating grease of the present invention has a molecular weight of 1000-100.
00 is used. In the examples shown below, polyoxypropylene glyceryl ether having an average molecular weight of 3000 is used.

[Chemical 2]

In the lubricating grease of the present invention, a thickening agent generally used can be selected as a thickening agent depending on the use of the lubricating grease, and is not particularly limited. Commonly used thickeners include lithium soap, lithium complex, calcium soap, calcium complex, sodium soap, aluminum soap, aluminum complex, organic bentonite, silica gel, urea, sodium terephthalate, etc. The one that fits is selected.

In the examples shown below, water resistance, heat resistance,
Lubrication performance indicates a lubricating grease containing lithium soap. The amount of the thickener is determined so that it can be used as a lubricating grease in the consistency range to be used. In order to adjust the commonly used lubricating grease of NLGI consistency No. 000 to No. 4, it is necessary to prepare 2 to 30 with respect to the total weight.
% Thickener is used. In the example of the lubricating grease used for the bearing of the soft ground improvement device shown below, the lubricating grease is adjusted to NLGI consistency No. 00 to No. 2, so that it is increased by 2.5 to 20% with respect to the total weight. A sticking agent is used.

In the lubricating grease of the present invention, powder may be added to adjust the density. It may not be added unless there is a need to adjust the density depending on the application, or if there are other requirements for lubricating performance. As the powder to be added, it is preferable to use a powder that does not impair the lubrication performance. Further, it is preferable to add powder having solid lubricity. As powder to be added, calcium carbonate, zinc white, polytetrafluoroethylene (PTF)
E), powder containing any one of molybdenum disulfide, organic molybdenum, MCA, tungsten disulfide, graphite, carbon fluoride, boron nitride, mica, zinc stearate, calcium stearate, aluminum stearate and polyethylene powder. It As the powder, a particle size of 0.5 μm or less to 200 μm or less is used depending on the application of the lubricating grease.

In the examples of the present invention shown below, the case where calcium carbonate or molybdenum disulfide is added is shown. Calcium carbonate is preferable because it is inexpensive, has low toxicity, and improves lubrication performance. In the examples, calcium carbonate having a particle size of 45 μm or less is used.

In the lubricating grease of the present invention, powder is added mainly for adjusting the density. Heavy powder is added to increase the density of the lubricating grease, and light powder is added to decrease the density. When it is not necessary to adjust the density, the powder may not be added. The density adjustment is performed for the purpose of floating or sinking the lubricating grease when it leaks into water. In some of the lubricating grease examples of the present invention, it settles when leaked into seawater,
Powder is added. Predicting the trend of lubricating grease with adjusted density after leakage is treated by suspending the lubricating grease and making it easier to collect it, or by letting the lubricating grease settle (not float) on the seabed (water bottom). It is preferable because it can

The lubricating grease of the present invention does not prevent addition of commonly used additives as necessary additives depending on the intended use. As additives, antioxidants, extreme pressure agents, oiliness agents, rust inhibitors, corrosion inhibitors, dyes,
There are hue stabilizers, thickeners, structure stabilizers and the like.

(Embodiment 1) Hereinafter, examples and comparative examples of the lubricating grease of the present invention will be specifically described. The preparation methods of Examples of the present invention and Comparative Examples are shown below.

Example 1) Polyoxypropylene glyceryl ether (65
1.0 g of 12-hydroxystearic acid (61.5
g) was added and heated to 80 to 90 ° C. to dissolve 12-hydroxystearic acid. 2) Lithium hydroxide-hydrate (8.5 g) previously heated and dissolved in tap water (85.0 g) was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C) 4) Next, polyoxypropylene glyceryl ether (2
79.0 g) was added and the mixture was allowed to cool to about 100 ° C. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease.

Example 1) Polyoxypropylene glyceryl ether (54
8.8 g) with 12-hydroxystearic acid (58.0).
g) was added and heated to 80 to 90 ° C. to dissolve 12-hydroxystearic acid. 2) Lithium hydroxide-hydrate (8.0 g) previously dissolved in tap water (80.0 g) by heating was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C) 4) Next, polyoxypropylene glyceryl ether (2
35.2 g) was added, the mixture was allowed to cool to about 100 ° C., and calcium carbonate (150.0 g) was added. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease.

Example 1) Polyoxypropylene glyceryl ether (47
2.0 g) to 12-hydroxystearic acid (51.8)
g) was added and heated to 80 to 90 ° C. to dissolve 12-hydroxystearic acid. 2) Lithium hydroxide-hydrate (7.2 g) previously heated and dissolved in tap water (72.0 g) was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C) 4) Next, castor oil (319.0 g) was added, and further about 1
After allowing to cool to 00 ° C., calcium carbonate (150.0 g) was added. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease.

Example 1) Polyoxypropylene glyceryl ether (54
8.8 g) with 12-hydroxystearic acid (58.0).
g) was added and heated to 80 to 90 ° C. to dissolve 12-hydroxystearic acid. 2) Lithium hydroxide-hydrate (8.0 g) previously dissolved in tap water (80.0 g) by heating was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C) 4) Next, polyoxypropylene glyceryl ether (2
35.2 g) was added, and after further cooling to about 100 ° C., molybdenum disulfide (150.0 g) was added. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease.

Comparative Example 1) Commercially available concentrated lubricating grease (lithium soap base / mineral oil grease) with a workability of 323 and a dropping point of 191 ° C.

Comparative Example 1 12-Hydroxystearic acid (46.6 g) was added to mineral oil (452.9 g) and heated to 80 to 90 ° C.
12-hydroxystearic acid was dissolved. 2) Lithium hydroxide-hydrate (6.4 g) previously heated and dissolved in tap water (64.0 g) was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C) 4) Next, add mineral oil (194.1 g), and further add about 10
After allowing to cool to 0 ° C., calcium carbonate (300.0 g) was added. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease having a workability of 315 and a dropping point of 192 ° C.

Comparative Example 1) 12-Hydroxystearic acid (79.1 g) was added to polyoxypropylene glycol monobutyl ether (588.0 g) and heated to 80 to 90 ° C.
Hydroxystearic acid was dissolved. 2) Lithium hydroxide-hydrate (10.9 g) previously heated and dissolved in tap water (109.0 g) was added and stirred to carry out saponification reaction and dehydration. 3) After completion of the reaction, heating was performed until the lithium soap was dissolved and the contents became transparent. (About 220 ° C.) 4) Next, polyoxypropylene glycol monobutyl ether (252.0 g) was added, and after further cooling to about 100 ° C., organic molybdenum (70.0 g) was added. 5) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease having a workability of 320 and a dropping point of 195 ° C.

Comparative Example 1) Bentonite (60.0 g) was dispersed in mineral oil (790.0 g) heated to about 90 ° C. 2) Tap water (1.0 g) was added thereto, and the mixture was stirred. 3) This was homogenized by a colloid mill and then defoamed to obtain a lubricating grease having a workability of 330 and a dropping point of 250 ° C. or higher. Comparative Example 1) Silica (35.0 g) was dispersed in polyoxypropylene glycol monobutyl ether (835.0 g) at room temperature, graphite (130.0 g) was further added, and the mixture was stirred. 2) This was homogenized with a colloid mill and then defoamed to obtain a lubricating grease having a workability of 326 and a dropping point of 250 ° C. or higher.

Table 1 shows the ingredients of the above Examples 1 to 3, and Table 2 of the ingredients of the Comparative Examples 1 to 3.

[Table 1]

[Table 2]

12-Hydroxystearic acid and lithium hydroxide-hydrate used in the above-mentioned Examples and Comparative Examples react with each other to form a lithium soap as a thickener. The respective amounts of 12-hydroxystearic acid and lithium hydroxide-hydrate are mixed in equivalent amounts necessary for the reaction. The total amount of 12-hydroxystearic acid and lithium hydroxide-hydrate, that is, the amount of the thickener, is related to the viscosity of the base oil, the required consistency of the lubricating grease, the powder to be added, and other additives. It is determined. In this example and comparative example, NLGI consistency number 1 and consistency 3 were used.
Formulated to be 10-340.

In the above Examples to Comparative Examples, the reason why the base oil is added again before heating after the saponification reaction and then after cooling is for cooling. The ratio of the base oil added for this cooling is usually 10 to 70% with respect to the entire base oil, but this ratio is not particularly limited.

Properties of Examples 1 to 3 are shown in Table 3 below.

[Table 3] As shown in Table 3, it was confirmed that the lubricating grease of the present invention represented by Examples 1 to 3 has suitable performance as a grease. .

Table 4 below shows the results of the underwater condition confirmation tests of Examples and Comparative Examples.

[Table 4] In Examples 1 to 3, good results were obtained because no oil film was confirmed in the state tests in tap water and artificial seawater. In this test, the lubricating grease of the example to which no powder is added floats in artificial seawater, but other examples ~
So it didn't float. From this, it was confirmed that it is possible to adjust the density of the lubricating grease by adding powder, and to adjust the floating / sinking of the lubricating grease in water. In Comparative Examples 1 to 3, an oil film was confirmed in all cases. Also, a comparative example ~
In the grease, the ups and downs were mixed. From the above results, the lubricating grease of the present invention represented by the formulations of Examples of the present invention is a lubricating grease that is less dispersed due to an oil film or the like, is environmentally friendly, and is easy to collect and perform other processing. It was confirmed that there is.

In the examples, polyoxypropylene glyceryl ether plus castor oil was prepared as the base oil, but good results were obtained in the property and underwater condition confirmation tests. From this, it was confirmed that it is possible to prepare a lubricating grease having improved biodegradability by mixing the lubricating grease of the present invention with a vegetable oil or a synthetic ester oil.

The physical properties and performances of the lubricating greases of Examples and Comparative Examples were evaluated by the methods shown below. (1) Worked Penetration The worked penetration was measured 60 times in accordance with the penetration test method specified in JIS K2220 5.3. (2) Drop point The drop point was determined according to the drop point test method specified in JIS K2220 5.4. (3) Density The density was measured according to the Hubbard pycnometer density test method specified in JIS K2249. (4) Apparent viscosity The apparent viscosity was determined according to the apparent viscosity test method specified in JIS K2220 5.15. (5) Mixing stability The mixing stability was determined according to the mixing stability test method specified in JIS K2220 5.11. (6) Tymken load carrying capacity The OK value was determined according to the Timken load carrying capacity test method specified in JIS K2220 5.16. (7) High-speed four-ball test (WEAR) “Standard” stipulated in ASTM D2266
Test Method for Wear Pre
Ventive Characteristics o
f Lubricating Grease (Four
-Ball Method) "
The wear scar diameter after rotation for 1 hour was measured under the conditions of rpm, load of 40 kgf / cm ² , and temperature of 75 ° C. The smaller this value is, the better the abrasion resistance is. (8) High-speed four-ball test (WP) “Standard” specified in ASTM D2296
Test Method for Measure
ent of Extreme-Pressure P
properties of Lubricating
Grease (Four-Ball Method) "
According to the above, WP (Weld Point; fusion load) was determined. (9) Underwater condition confirmation test In a 300 ml beaker, tap water or artificial seawater 200 m
1, 20 g of the sample was put, and the ups and downs of the sample and the presence or absence of an oil film on the water surface were visually confirmed. The artificial seawater was prepared by the following formulation. Distilled water 1000 g Sodium chloride 25 g Magnesium sulfate 2 g Magnesium chloride 4 g

(Embodiment 2) Embodiment 2 shows an example of a bearing used in water in which the lubricating grease of the present invention is used. In the second embodiment, as an example, a bearing used in a soft ground improvement device for improving soft ground, particularly a soft ground improvement device for modifying soft ground on the seabed is described. There is no limitation, and the lubricating grease of the present invention can be used in any place where the bearing or the lubricating grease is used.

FIG. 1 shows a schematic diagram of the soft ground improvement device 2. The soft ground improvement device 2 is mounted on the work boat 1. When used on the ground, it may be mounted on a vehicle. The soft ground improvement device 2 includes a speed reducer 3, a mast 4, a stirring shaft 5, a bearing 6, and an excavation / agitation blade 7. Work boat 1
Are anchored at the water surface 8 on the reforming seabed 9. Reduction gear 3, mast 4, stirring shaft 5, bearing 6, excavation and stirring blade 7
The part including is lowered to the seabed. Next, excavation / agitation blade 7
Excavates and agitates the seabed 9 to the depth of the reforming layer 10 that is reformed while rotating. Next, the soft ground improvement device 2 injects the slurry-like concrete into the reforming layer 10 through the inside of the stirring shaft 5, and at the same time, the excavating and stirring blade 7 rotates to stir the concrete and the soil in the reforming layer. While the speed reducer 3,
A portion including the mast 4, the stirring shaft 5, the bearing 6, and the excavation / agitation blade 7 is pulled up from the reforming layer 10. Thereby, the modified layer 1
0 soil and concrete are mixed to form a modified layer.

The speed reducer 3 transmits the rotation to the stirring shaft 5 at an appropriate rotation speed. As the stirring shaft 5 rotates, the excavation / agitation blade 7 mounted near the tip of the stirring shaft 5 rotates. The stirring shaft 5 is hollow so that concrete can pass therethrough, and a hole for letting out concrete is formed near the tip or in the excavation / agitation blade 7. The mast 4 supports the shake of the stirring shaft 5 via a bearing 6 fixed to the mast 4. The excavation / agitation blade 7 rotates to excavate to dive into the seabed and stir the ground and the ground and the concrete. The excavation / agitation blade 7 has a plurality of blades attached to the agitation shaft 5 in a plurality of stages. One or more stirring shafts 5 are provided for one soft ground improvement device 2. There may be a plurality of masts 4 depending on the number of supporting stirring shafts 5, and the mast 4 may be installed so as to support the plurality of stirring shafts 5.

As shown in FIG. 1, the bearing 6 may be mounted in a plurality of stages with an appropriate span in order to suppress the shake of the stirring shaft 5. Details of the bearing 6 are shown in FIG.

In FIG. 2, a lip seal type bearing 6 is illustrated. The bearing 6 is fixed to the mast 4, surrounds the periphery of the stirring shaft 5, allows the stirring shaft 5 to move in the thrust direction by a predetermined amount, and prevents the stirring shaft 5 from moving in the radial direction. The bearing 6 in which the lubricating grease of the present invention is used is not limited to the lip seal type, and includes side seal types and other types of bearings in which lubricating grease is used.

The bearing 6 includes a bearing metal 11, a seal 12,
A bearing case 13, a seal case 14, and a grease greasing means 16 are provided. The bearing 6 is the bearing main shaft 17 of the stirring shaft 5.
Mounted on the section.

The bearing 6 is used in water and soil,
If foreign matter enters the inside, the bearing metal 11 and the bearing main shaft 17 may be damaged, and if used further, the bearing case 13 and the seal case 14 may be damaged. For this reason, the lubricating grease is injected between the bearing 6 and the bearing main shaft 17 by the grease greasing means 16 at a pressure against water pressure or earth pressure. As the lubricating grease injected here, NLGI consistency Nos. 00 to 2 are generally used so that it can be injected. A part of the injected lubricating grease may leak from the gap 15 between the bearing 6 above and below the bearing 6 and the bearing main shaft 17. In this way, the lubricating grease leaks into water or soil. If the lubricating grease that leaks into the water is not dispersed, it will be easier to collect or the environmental impact will be smaller.

In addition, the lubricating grease used in excavators used in the soil is also environmentally friendly and easy to remove if it does not disperse even if it leaks to groundwater or the like.
Further, it is preferable that the grease leaked to the ground and other environments does not diffuse due to rainwater or the like.

Thus, if the density-adjusted lubricating grease is used in bearings used in water or soil, or where grease may leak to the environment, the load on the environment will be reduced. Is reduced. Further, if the leaked lubricating grease is less diffused and the lubricating grease that does not form an oil film by separating the oil is used, the load on the environment is reduced.

Such lubricating grease is used for underwater excavators, pumps, bearings of equipment having a rotating part including a power generator, a rotation supporting part, and other parts which may leak into water by using lubricating grease. It is more desirable to be used in.

[0060]

The lubricating grease of the present invention can reduce the load on the environment without forming an oil film when it leaks into water. Furthermore, the lubricating grease of the present invention has an adjustable density, and can be adjusted so as to float or sink when leaking into water. The bearing using the lubricating grease of the present invention can reduce the load on the environment when used in water.

[Brief description of drawings]

FIG. 1 is a schematic view of a soft ground improvement device.

FIG. 2 is a schematic view of a bearing portion of a soft ground improvement device.

[Explanation of symbols]

1 work boat 2 Soft ground improvement device 3 reducer 4 masts 5 stirring shaft 6 bearings 7 Excavation and stirring blades 8 water surface 9 seabed 10 Modified layer 11 Bearing metal 12 seals 13 Bearing case 14 seal case 15 Gap 16 Grease supply means 17 Bearing spindle

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C10M 125/10 C10M 125/10 125/22 125/22 F16C 17/14 F16C 17/14 33/10 33 / 10 Z // C10N 10:02 C10N 10:02 10:04 10:04 10:12 10:12 40:02 40:02 50:10 50:10 (72) Inventor Takao Yoshimatsu Small Suma Ward, Kobe City, Hyogo Prefecture 1-1-13 Teramachi Nihon Grease Co., Ltd. Technical Research Laboratory (72) Inventor Akihiro Yamamoto 1-1-13 Kodera Town, Suma-ku, Kobe-shi, Hyogo Nihon Grease Co., Ltd. Technical Research Laboratory (72) Yuzo Kitamura Hyogo 1-1, Wadasaki-cho, Hyogo-ku, Kobe-shi, Japan F-term in engineering center engineering machinery MHI Corporation (reference) 3J011 AA06 AA20 BA02 JA02 MA22 PA10 RA02 4H104 AA04C AA13C AA19C AA24C AA26C BB16B BB17B CB45A CA02 A CB16A CD02C DA06A EA08C FA01 FA02 FA03 FA06 PA01 QA18

Claims (11)

[Claims] 1. A lubricating grease containing polyoxyalkylene glyceryl ether. 2. A lubricating grease containing polyoxypropylene glyceryl ether. 3. A lubricating grease containing a powder for adjusting density. 4. The powder is a solid lubricant, The lubricating grease according to claim 3. 5. The powder includes calcium carbonate, zinc white, polytetrafluoroethylene (PTFE), molybdenum disulfide, organic molybdenum, MCA, tungsten disulfide,
Graphite, carbon fluoride, boron nitride, mica, zinc stearate, calcium stearate, aluminum stearate, polyethylene powder, or 2
The lubricating grease according to claim 3, which is a mixture of the above. 6. The powder is calcium carbonate, The lubricating grease according to claim 3. 7. The lubricating grease according to claim 3, which contains a polyoxyalkylene glyceryl ether. 8. The lubricating grease according to claim 3, which contains polyoxypropylene glyceryl ether. 9. A lubricating grease containing polyoxypropylene glyceryl ether, calcium carbonate, and lithium soap. 10. A bearing, which uses the lubricating grease according to any one of claims 1 to 9. 11. A bearing used in water, which uses the lubricating grease according to any one of claims 1 to 9.