JP2007016066A - Method for lubrication in mechanical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubrication method with which contamination of surrounding environment of seawater, etc., is prevented in lubrication around sliding parts of a ground treatment machine of the sea bottom. <P>SOLUTION: The lubrication method comprises using biodegradable grease that has a high density and is sedimented in sea water. The grease, for example, comprises a biodegradable base oil, a thickening agent and a specific gravity adjuster. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is, for example, a mechanical device such as a ground processing machine that injects cement into a ground such as soft ground, a drilling machine that excavates the ground, an actuator that reciprocates a load body such as a gate, and the like. The present invention relates to a lubrication method in a mechanical device that supplies lubricating grease around a sliding portion such as a bearing that rotatably supports a rotary shaft that is movably supported and around a sliding portion of a reciprocating member.

  Conventionally, a deep mixing method is known for ground improvement. In the deep mixing method, for example, an improved layer of soft ground such as the sea floor is excavated and agitated with a drilling machine, a slurry cementitious hardener is injected into the excavated soil, and the excavated soil and cementitious hardener are agitated and mixed. This is a mechanical stirring type ground treatment method that solidifies the mixed material. Cement-based hardeners are prepared by mixing measured cement, water, and AD agent with a mixer, feeding the mixed material stirred with an agitator to a processing machine while measuring it with a pressure pump, and supplying it to the excavated soil through a rotating shaft. , Mixing with stirring blades to solidify. In such a ground processing machine, the rotating shaft is rotatably supported by a supporting steel pipe via a bearing, and it is necessary to supply lubricating grease to the bearing. At present, various types of lubrication grease are supplied to the bearings of excavators, and those that float on the water surface and those that settle on the bottom of the water are known.

  Conventionally, tail seal compositions for shield machines are known. The composition comprises 55 to 33% by weight of biodegradable base oil, biodegradable grease, or a mixture thereof, 12 to 2% by weight of biodegradable pour point depressant, powdered inorganic substance, paste 30 to 60% by weight of an inorganic substance or a mixture thereof, and 30 to 60% by weight of a fiber having a length of 1 to 5 mm and a thickness of 0.5 to 2 denier, and an NLGI consistency grade of 150 to 280 ( For example, see Patent Document 1).

  In addition, biodegradable grease compositions are known that have biodegradability in a pre-environment and have lubrication life and oxidation stability. It includes a base oil containing at least 80% of a linear fatty ester of 2n carbon atoms of pentaerythritol, a thickener, a sulfur-phosphorus extreme pressure agent and an antioxidant (see, for example, Patent Document 2).

In addition, as a biodegradable grease composition, one based on vegetable oil is known. The biodegradable grease composition contains at least 80% by weight of a vegetable oil having a kinematic viscosity of 25 to 80 mm ² / s at 40 ° C. as a base oil, calcium soap, organic bentonite, silica thickener, sulfur- It contains a phosphorous extreme pressure agent and an antioxidant (for example, see Patent Document 3).

  In addition, biodegradable grease compositions that are excellent in water-washing water resistance are known. The biodegradable grease composition uses ester oil or animal and vegetable oil as a base oil to which inorganic substances such as silica, alumina, magnesia, metal soap, and a thickener are added (for example, see Patent Document 4). .

In addition, the applicant has developed a biodegradable grease composition that is largely decomposed even when mixed in rivers, groundwater, soil, oceans, etc., and has no water pollution, soil pollution, or ocean pollution. A patent application has been known. The biodegradable grease composition contains at least 80% by weight or more of a polyol ester oil as a base oil, and a thickener is added thereto to make the biodegradation rate 80% or more (for example, Patent Document 5). reference).
Japanese Patent Laid-Open No. 9-208943 JP-A-8-20789 JP-A-8-20788 JP 2003-277780 A JP-A-6-1989

  However, in conventional mechanical equipment such as the ground treatment method, the lubricating grease supplied around the bearing, which is the sliding part of the rotating shaft of the ground treatment machine, is lubricated because the base oil of the main raw material is mineral oil. In the case of leakage at the specified location, there was a problem that the lubricating grease remained in that location without biodegradation. For example, when the ground treatment machine is used at sea, the specific gravity of the lubricating grease is about 0.9, and there is a problem that the lubricating grease floats on the sea surface and contaminates the seawater. Therefore, it is necessary to collect the lubricating grease that has floated on the sea surface, and there is a problem in that industrial waste disposal costs are incurred because the collected lubricating grease is processed. In addition, when transferring a work ship equipped with a ground treatment machine, it is necessary to remove the lubricating grease adhering to the ship bottom prior to that, or to wash the lubricating grease attached to the ground treatment machine and remove it from the ground treatment machine. For this reason, there are problems that high cost is required for the post-processing and that the surrounding environment is contaminated by contaminating seawater.

  In addition, in conventional ground treatment machines, lubricating grease that is settling in seawater, for example, lubricating grease in which lithium soap is added to polyglycol oil, which is a synthetic oil, is used as the base oil. Is known to sink to the bottom of the sea without rising to the sea surface, but such lubricating greases are not biodegradable because of such a lubricating grease. In addition to being contaminated, there has been a problem that lubricating grease may be dissolved in seawater or transported into seawater and scattered in the seawater for a long time, contaminating the surrounding environment such as seawater.

  In order to solve the above-described problems, the object of the present invention is to provide at least a specific gravity for lubricating grease to be supplied around a support member such as a bearing that rotatably supports a rotating shaft of a mechanical device such as a ground treatment machine. Another object of the present invention is to provide a lubrication method in a mechanical device that prevents the contamination of the surrounding environment by making the lubrication grease biodegradable and decomposing the lubrication grease by bacteria to return it to a harmless substance.

The present invention relates to a lubrication method in a mechanical device that lubricates the sliding portion by supplying lubricating grease to the sliding portion between the relative moving members in the mechanical device having relative moving members that move relative to each other.
At least a biodegradable grease that settles in seawater was used as the lubricating grease to be fed around the sliding portion that supports the other relative movement member penetrating the other movement member. The present invention relates to a lubrication method in a mechanical device.

  In the lubrication method in this mechanical device, the biodegradable grease is substantially composed of 60 to 90 wt% base oil and 40 to 10 wt% of an additive such as a thickener and a specific gravity adjusting material.

In the lubrication method in this mechanical device, the biodegradable grease has a density of 1.1 g / cm ³ or more.

In the lubrication method in this mechanical apparatus, the biodegradable grease is a synthetic oil such as polyol ester oil and / or a biodegradable oil such as vegetable oil as the base oil, and lithium-calcium soap, lithium soap, calcium as the thickener. One or more selected from soaps, aluminum soaps, composite soaps thereof, and zinc oxide (ZnO), molybdenum disulfide (MoS ₂ ), titanium oxide (TiO ₂ ) that do not impair lubricity as the specific gravity adjusting additive, Graphite, PTFE (polytetrafluoroethylene), MCA (melamine cyanurate), calcium carbonate (CaCO ₃ ), boron nitride (BN), tungsten disulfide (WS ₂ ), talc, mica, copper powder, alumina powder, etc. One selected from metal powders that do not impair lubrication performance Are those more is added.

  In the lubrication method in this mechanical device, the biodegradable grease can be used in a temperature range of −50 ° C. to + 130 ° C. When used on the seabed or the like, a temperature range of about 0 ° C. to 80 ° C. is a preferable temperature condition for practical use. Synthetic oils can be used without condensing even at a minimum temperature of −50 ° C., but vegetable oils and animal oils have a practical minimum temperature of about 0 ° C.

  The mechanical device is a machine in which a cemented hardened material slurried is poured into excavated soil excavated from a soft ground such as the seabed, and a mixed material obtained by stirring and mixing the excavated soil and the cemented hardened material is solidified. It is a support device for reciprocating a load body such as a sluice, a gate, a valve, or the like, or an excavator that excavates the ground such as an agitating type ground treatment machine, a shaft, a tunnel, a ground at the bottom of a water.

  Further, in the ground processing machine in the mechanical device, one of the relative movement members is a rotation shaft, and the other relative movement member is disposed on a slide shaft so as to be rotatably supported. And at least one of the rotating shafts has a supply path for the cementitious hardener, and the lubricating grease drives the grease pump at least around the sliding portion that rotatably supports the rotating shaft. The grease is supplied through a grease hose.

  Furthermore, the ground treatment machine is mounted on a work ship in order to solidify the soft ground on the seabed or water bottom by mixing the cement-based hardener.

  In the lubrication method in this mechanical device, the rotary shaft in the ground treatment machine is composed of a drive rotary shaft having a drilling blade and a stirring blade at the tip and a connected rotary shaft that is sequentially added to and connected to the drive rotary shaft, The supporting steel pipes are respectively disposed in a connecting portion having the sliding portion between the drive rotating shaft and the connecting rotating shaft and a connecting portion having the sliding portion between the connecting rotating shafts. is there.

  In the lubrication method in the mechanical apparatus, the biodegradable grease is excavated from the soft ground by the excavating blade provided on the rotary shaft in the ground processing machine, and the connecting portion of the rotary shaft is sequentially applied to the soft ground. When the grease enters the soft ground, the grease pump is operated around the sliding portion of the connecting portion that has entered the soft ground, and the grease is sequentially supplied from the grease tank through the grease hose, and the rotating shaft from the soft ground is supplied. In accordance with the withdrawal, the lubrication around the sliding portion is stopped.

  As described above, the lubrication method in the mechanical device according to the present invention uses the biodegradable grease that settles at least in the seawater as the lubrication grease supplied to the bearing between the relative moving members. Even if there is something that comes out, the lubricating grease is non-toxic and biodegraded naturally without floating on the water surface such as the sea surface, contaminating the bottom of the ship or contaminating the water such as sea water. It is safe and reliable, and environmental pollution does not occur. In addition, the lubricating grease of this case has excellent water resistance and is difficult to flow out of the bearing, but even if it is leaked, there is no need to collect the leaked grease, thus eliminating the need for industrial waste processing costs for collecting grease and making it inexpensive. Can be manufactured. Further, in this lubrication method for a mechanical device, the biodegradable grease used in the present invention can be prepared by adding an additive such as a specific gravity adjusting material to an existing biodegradable grease. Can be prepared and manufactured very easily.

  The lubrication method in the mechanical device according to the present invention includes, for example, a ground processing machine for improving the ground such as the soft bottom of the water bottom and the sea bottom to a solid ground, an excavator for excavating the ground such as the water bottom, the sea bottom, a tunnel, and a shaft. It is preferably applied to lubrication of a mechanical device such as a support device for reciprocating a load body such as a sluice gate, a gate and a valve. As shown in FIGS. 1 to 4, the lubrication method in this mechanical apparatus is such that one of the relative movement members is operated in water and the rotation shaft 2 is moved relative to each other, and the other relative movement member is a rotatable rotation shaft 2. It can be applied to the ground processing machine 1 which is a mechanical device composed of a support steel pipe 3 having a bearing 4 to be supported, and the bearing 4 which is a sliding portion between the rotary shaft 2 and the support steel pipe 3 is lubricated with grease. It lubricates moving parts. Alternatively, although not shown, the lubrication method in this mechanical apparatus is applied to an excavator comprising a drive shaft and a base or a machine base having a bearing that slidably or rotatably supports the drive shaft as one relative moving member. It is possible to lubricate the sliding portion by supplying lubricating grease to the sliding portion between the drive shaft and the base or machine base. Alternatively, although the lubrication method in this mechanical device is not shown, the load in the mechanical device having a support member such as a rope and a slidably supported base or machine base that supports the support member as one relative moving member. It can be applied to a body support device, and lubricates the sliding portion by lubricating the sliding portion between the support member and the base or machine base.

  In the following, as an embodiment, a description will be given of an example applied to the ground processing machine 1 for improving the ground of the seabed 29 and the soft ground 21 of the waterbed to a firm ground. The matters described below also apply to the load body support device. The lubrication method in this mechanical device is particularly around the bearing 4 which is a sliding portion which supports the support steel pipe 3 which is the other relative movement member penetrating the rotary shaft 2 which is one relative movement member so as to be relatively movable. As the lubricating grease to be lubricated, at least biodegradable grease 20 that settles in seawater is used.

The biodegradable grease 20 is substantially composed of 60 to 90 wt% base oil and 40 to 10 wt% additives such as a thickener and a specific gravity adjusting material. Additives in the biodegradable grease 20 can be added with additives having specific properties in order to improve load bearing performance, wear resistance, and water resistance in addition to the specific gravity adjusting material. In addition, the specific gravity adjusting material is added to the biodegradable grease 20 so that the density is substantially 1.1 g / cm ³ or more.

In the lubrication method in this mechanical apparatus, as the base oil, for example, synthetic oil such as polyol ester oil and / or biodegradable oil such as animal and vegetable oil can be used, and it is particularly preferable to use polyol ester oil. Further, the thickener is one or more selected from lithium-calcium soap, lithium soap, calcium soap, aluminum soap, and composite soap thereof, and it is particularly preferable to use lithium-calcium soap. Furthermore, the additive of the specific gravity adjusting material is a substance that does not impair the lubricity, such as zinc oxide (ZnO), molybdenum disulfide (MoS ₂ ), titanium oxide (TiO ₂ ), graphite, PTFE (polytetrafluoroethylene), MCA (melamine cyanurate), calcium carbonate (CaCO ₃ ), boron nitride (BN), tungsten disulfide (WS ₂ ), talc, mica, copper powder, selected from metal powders that do not hinder the lubricating performance In particular, it is preferable to use calcium carbonate. The biodegradable grease 20 is configured to be used in a temperature range of −50 ° C. to + 130 ° C.

  In this embodiment, the lubrication method in this mechanical device is applied to the ground processing machine 1 as the mechanical device. In the ground processing machine 1, as shown in FIG. The other relative movement member is a support steel tube 3 that is disposed in a spaced state on a slide tube 5 that is a slide shaft and that rotatably supports the rotary shaft 2. Further, at least one of the rotating shafts 2 has a cement supply passage 22 of a cement-based hardener, and is driven from the grease tank 6 by a drive of the grease pump 7 around a sliding portion where the lubricating grease is rotatably supported. Each is supplied through a grease hose 8. Here, the grease tank 6 is a general term for movable containers such as drum cans, bellows containers, and pallet containers that can be transported, and installed containers such as tanks installed on the work boat 13 and the machine base. . In addition, the grease hose 8 is illustrated in FIG. 2 so as to extend into the seawater 28 for easy understanding, but preferably, for example, if the grease hose 8 is disposed along the slide tube 5, damage or the like may occur. Of course, it is preferable. Each of the connecting portions 25 of the biodegradable grease 20 is supplied with a grease pump 7 for supplying the biodegradable grease 20 to each connecting portion 25. The grease pump 7 is supplied from the grease tank 6, respectively. The biodegradable grease 20 is supplied to each connecting portion 25 through the grease hose 8. As shown in FIG. 3, the rotary shaft 2 is rotatably supported by a support steel pipe 3 disposed on the slide pipe 5 in a spaced state. The slide tube 5 extends between a pair of adjacent rotating shafts 2, and the supporting steel tube 3 is rotatably supported by a pair of adjacent rotating shafts 2 via a bearing 4.

  As shown in FIGS. 1 to 4, the ground treatment machine 1 is mounted on the work boat 13 in order to solidify the soft ground 21 on the seabed 29 by mixing a cement-based hardener. A ground processing machine 1 is mounted on the work boat 13, and the ground processing machine 1 constitutes a ground processing machine 1 such as a plant 14, a cement silo 15, a tower 17, a hydraulic jack 18, a generator 19, and a motor 9. And a central control room 16 having a control device for controlling these devices. Further, in this lubrication method in the mechanical apparatus, the rotary shaft 2 in the ground processing machine 1 is, as shown in FIG. 3, a power transmission means 30 having a speed reducer 12 to which the rotation of the motor 9 is transmitted, a guide mechanism, etc. From the driving rotary shaft 23 provided with the excavating blade 10 and the stirring blade 11 at the tip portion 26, and a plurality of connecting rotary shafts 24 that are sequentially connected to the driving rotary shaft 23 and transmitted from the power transmission means 30. Become. Further, the support steel pipe 3 is disposed in a connecting portion 25 between the drive rotating shaft 23 and the connecting rotating shaft 24 and a connecting portion 25 between the connecting rotating shafts 24. As shown in FIGS. 2 and 4, the connecting rotary shaft 24 is connected in five stages, and a driving rotary shaft 23 including the excavating blade 10 and the stirring blade 11 is connected to the forefront of the connecting rotary shaft 24. Has been.

  Next, the timing of supplying the biodegradable grease 20 will be described. As shown in FIG. 4, in the lubrication method in this mechanical apparatus, the operation of the ground processing machine 1 is controlled in the central control chamber 16, but when starting work, the generator 19 is generated to operate the hydraulic jack 18. The tower 17 is moved to set the ground processing machine 1 at a predetermined position, and the rotary shaft 2 is lowered toward the seawater 28, and the drive rotary shaft 23 enters the sea surface 27 and sinks into the seawater 28 (step S1). ). Next, the drive rotary shaft 23 of the ground processing machine 1 is made to reach the seabed 29, and the motor 9 is driven to rotate the connecting rotary shaft 24 and the drive rotary shaft 23 via the speed reducer 12 (step S2). The drive rotary shaft 23 is driven to rotate, and the excavating blade 10 excavates the soft ground 21 on the seabed to allow the rotary shaft 2 to penetrate the soft ground 21, and then slides on the connecting portion 25 of the rotary shaft 2 that has entered the soft ground 21. In order to supply the biodegradable grease 20 around the moving part, the grease pump 7 is sequentially driven to supply the biodegradable grease 20 around the sliding part from the grease tank 6 through the grease hose 8 sequentially. While the agitating blade 11 is agitating the excavated soil, the cement-based hardener is supplied to the excavated soil from the cement silo 15 through the cement supply passage 22 of the rotary shaft 2 and mixed (step S3). In FIG. 4, the connecting portion 25 supplied with the biodegradable grease 20 is indicated by a cross. When the rotating shaft 2 reaches a predetermined position of the soft ground 21 to be ground improved (step S4), the ground processing machine 1 stops the supply of the cement-based hardener, and then rotates the rotating shaft 2 while rotating the rotating shaft 2. The operation moves to pulling 2 out of the soft ground 21. Next, when the rotating shaft 2 is pulled out from the soft ground 21, the operation of the motor 9 that drives the rotating shaft 2 is stopped, and the biodegradable grease 20 is supplied around the sliding portion of the connecting portion 25. The grease pump 7 is sequentially stopped to stop supplying the biodegradable grease 20 (step S5). Next, when the connecting portion 25 of the rotating shaft 2 is pulled out into seawater, the operation of all the grease pumps 7 is stopped, the supply of the biodegradable grease 20 to the connecting portion 25 is stopped, and the ground treatment machine 1 The operation is stopped (step S6).

Specifically, the biodegradable grease 20 used in the lubrication method in this mechanical device is obtained by adding a lithium-calcium soap thickener to a biodegradable synthetic ester base oil and using a calcium carbonate specific gravity adjusting material. It was added, and its specific gravity sufficient to sink into seawater was about 1.1, and it passed the copper plate corrosion test. When various properties of the biodegradable grease 20 produced here are measured, the consistency is 220 to 430 WP, preferably about 315, the dropping point is 187 ° C., and the oil separation degree is 100 ° C. for 24 hours. Was 2.5 mass%, and it was confirmed that the evaporation amount was 0.22 mass% in a 22-hour test at 99 ° C. Furthermore, the biodegradable grease 20 has a water resistance of 1.4% by weight in a 1 hour test at 79 ° C., and it was confirmed that the water has high water resistance. Biodegradable greases 20 has an apparent viscosity of 51.3Pa · s at 10 sec ^-1 at 0 ° C., a 12.3Pa · s at 100 sec ^-1, is good pumpability of the grease pump 7 I was able to confirm that. The biodegradable grease 20 was 0.39 mm in a 4-ball wear resistance test, 75 ° C., 1200 rpm, 40 kgf, 1 hour, and it was confirmed that the wear resistance was good. Furthermore, the biodegradable grease 20 was 0.52 mm in 10% water-containing 4-ball wear resistance test, 75 ° C., 1200 rpm, 40 kgf, 1 hour, and it was confirmed that the water-containing lubricity was good.

  The biodegradable grease 20 is as described above and has high biodegradability and low acute toxicity that can acquire the new standard Eco Mark. It settles in seawater and costs are higher than existing high specific gravity grease. It was inexpensive and it was confirmed that general properties such as lubricity, water resistance, and pumpability were equal to or better than existing lubricating grease. The biodegradable grease 20 has a biodegradability degree that satisfies the new Eco Mark standard and has a large specific gravity, so it can be expected not to pollute the sea floor and the sea surface, and it may be non-toxic in the acute toxicity test by Himedaka. It could be confirmed. Furthermore, the biodegradable grease 20 exhibits load-bearing performance and wear resistance performance that exceeds that of general-purpose greases. In particular, it can be confirmed that it can be used in a wide temperature range (-50 ° C to + 130 ° C), and has excellent water resistance. It was confirmed that it was difficult to flow out even in areas where water was splashed, and that it had good pumpability equivalent to that of current grease. In particular, the biodegradable grease 20 has good water-containing lubricity and high water resistance, so that it can be expected that the grease supply amount can be reduced by applying the biodegradable grease 20 to the seabed ground treatment machine 1.

  The lubrication method in the mechanical device according to the present invention is particularly applicable to a ground processing machine that improves the ground such as the soft ground such as the seabed to a solid ground, an excavator that excavates the ground such as the seabed, or a sluice, gate, valve, etc. This is preferred when applied to lubrication of a mechanical device such as a support device for reciprocating a load body.

It is a schematic explanatory drawing which shows the concept of the ground processing machine for achieving the lubrication method in the mechanical apparatus by this invention. FIG. 2 is a schematic diagram for explaining a concept of supplying lubricating grease around a sliding portion of a support steel pipe that rotatably supports a rotating shaft in the ground processing machine of FIG. 1. It is the schematic which shows the concept which supports the rotating shaft provided with the excavation blade and the stirring blade in the ground treatment machine of FIG. It is explanatory drawing which shows the grease supply timing around the sliding part in the ground processing machine of FIG.

Explanation of symbols

1 Ground treatment machine 2 Rotating shaft (Relative moving member)
3 Support steel pipe (relative movement member)
4 Bearing (sliding part)
DESCRIPTION OF SYMBOLS 5 Slide pipe 6 Grease tank 7 Grease pump 8 Grease hose 10 Excavation blade 11 Stirring blade 13 Work ship 20 Biodegradable grease 21 Soft ground 23 Drive rotation shaft 24 Connection rotation shaft 25 Connection portion 26 Tip portion 27 Sea surface 28 Sea water 29 Sea bottom

Claims (10)

In a lubrication method in a mechanical device that lubricates the sliding portion by supplying lubricating grease to the sliding portion between the relative moving members in the mechanical device having relative moving members that move relative to each other,
At least a biodegradable grease that settles in seawater was used as the lubricating grease to be fed around the sliding portion that supports the other relative movement member penetrating the other movement member. A lubrication method in a mechanical device. The biodegradable grease is substantially composed of 60 to 90 wt% base oil and 40 to 10 wt% additives such as thickener and specific gravity adjusting material. A lubrication method in the machine device described. The lubrication method for a mechanical device according to claim 1, wherein the biodegradable grease has a density of 1.1 g / cm ³ or more. The biodegradable grease includes a synthetic oil such as polyol ester oil as the base oil and / or a biodegradable oil of animal and vegetable oils, lithium-calcium soap, lithium soap, calcium soap, aluminum soap as the thickener, One or more kinds selected from those complex soaps, and zinc oxide, molybdenum disulfide, titanium oxide, graphite, PTFE, MCA, calcium carbonate, boron nitride, tungsten disulfide, talc, mica, as the specific gravity adjusting additive, The lubrication method for a mechanical device according to claim 2 or 3, wherein one or more selected from metal powders such as copper and alumina are added. The method for supplying lubricating grease according to any one of claims 1 to 4, wherein the biodegradable grease can be used in a temperature range of -50 ° C to + 130 ° C. The mechanical device is a mechanical agitation type in which a cemented hardened material that is slurried is poured into excavated soil excavating soft ground such as the seabed, and a mixed material obtained by stirring and mixing the excavated soil and the cemented hardened material is solidified. A ground treatment machine, a shaft, a tunnel, an excavator that excavates the ground such as a ground at the bottom, or a support device that reciprocates a load body such as a sluice, a gate, and a valve. 6. A lubrication method for a mechanical device according to any one of 5 above. The ground processing machine in the mechanical apparatus has a support in which one of the relative movement members is a rotation shaft, and the other relative movement member is disposed on a slide shaft in a spaced state to rotatably support the rotation shaft. The biodegradable grease is a steel pipe, wherein at least one of the rotary shafts has a supply passage for the cement-based hardener, and the biodegradable grease is at least around the sliding portion that rotatably supports the rotary shaft by the support steel pipe. The lubrication method for a mechanical device according to claim 6, wherein each grease is supplied from a grease tank through a grease hose by driving a grease pump. 8. The lubrication method for a mechanical device according to claim 7, wherein the ground processing machine is mounted on a work ship in order to mix and solidify the cement-based hardener on the soft ground on the seabed or water bottom. . The rotary shaft in the ground treatment machine is composed of a drive rotary shaft having a drilling blade and a stirring blade at the tip, and a connected rotary shaft that is sequentially added to and connected to the drive rotary shaft, and the support steel pipe has the drive rotary shaft 9. The connecting portion having the sliding portion between the shaft and the connecting rotating shaft and the connecting portion having the sliding portion between the connecting rotating shafts are respectively disposed on the connecting portion. The lubricating method in the machine apparatus as described in 2. The biodegradable grease is produced when the soft ground is excavated by the excavating blade provided on the rotary shaft of the ground processing machine and the connecting portion of the rotary shaft sequentially enters the soft ground. The grease pump is operated around the sliding part of the connecting part that has entered the ground, and is sequentially supplied from the grease tank through the grease hose, and the sliding is performed in accordance with the extraction of the rotating shaft from the soft ground. The lubrication method for a machine apparatus according to claim 9, wherein the lubrication around the part is stopped.

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