JP6283458B2 - Manufacturing method of shaft member - Google Patents

Description

The present invention includes a shaft member that rotates, the shaft portion of the shaft member about the method of manufacturing a shaft member definitive to the bearing device comprising a sliding bearing member having a slidable sliding surfaces.

Industrial equipment having a rotating portion includes a bearing device including a rotating shaft member and a bearing member that supports rotation and load of the shaft member. The bearing member has the following parts for supporting the rotation and load of the shaft member over a long period of operation: 1. Excellent durability. 2. No seizure or adhesion occurs. 3. Less frictional heat; It is required that the frictional sound is low.
This bearing member is roughly classified into a rolling bearing and a sliding bearing. Rolling bearings are broadly classified into ball bearings based on rolling ball bearings and roller bearings based on rolling such as cylindrical rollers and conical rollers. In a rolling bearing, a rolling part called a rolling element supports the rotation and load of a shaft member. This rolling element is sandwiched between the inner ring and the outer ring, and has a structure in which the rolling element is held by a cage, so that it is larger and more expensive than a plain bearing. Further, when the shaft member rotates at a high speed, the inertial force of the rolling element increases and an excessive load is applied to the rolling element cage. Alternatively, stress is repeatedly applied to the raceway surface of the rolling element even under a static load. For this reason, the life is short compared with the slide bearing using fluid lubrication. Furthermore, the quietness is inferior to that of the slide bearing due to rolling of the rolling elements.

On the other hand, the sliding bearing receives the rotation and load of the shaft member with an oil film of lubricating oil existing on the sliding surface. Compared to a lubrication device that supplies lubricating oil to the sliding surface or a hydrodynamic / hydrostatic bearing with a lubrication mechanism, a lubrication device that supplies lubricating oil to the sliding surface or an oil-impregnated bearing that omits the lubrication mechanism is small and inexpensive. Compared to hydrodynamic and hydrostatic bearings, it is used in more industrial machines.
The oil-impregnated bearing vacuum-impregnates a porous material made of a sintered body with lubricating oil. The vacuum-impregnated lubricating oil expands in volume by frictional heat on the sliding contact surface, and has a self-lubricating property that supplies the lubricating oil to the sliding surface. The lubricating oil that has oozed out on the sliding surface forms an oil film on the sliding surface. The presence of this oil film prevents seizure and adhesion with the shaft member. Then, when the shaft member rotates, a pressure distribution is formed in the oil film based on the equation of the lay nozzle. In the positive pressure part of the oil film, the lubricating oil enters the bearing member from the pores present on the sliding surface. On the contrary, in the negative pressure part of the oil film, the lubricating oil is discharged from the pores of the bearing member to the sliding contact surface. Thus, the self-circulation of the lubricating oil is performed on the slip surface through the pores of the slip surface due to the pressure distribution of the oil film formed on the slip surface. Further, the positive pressure portion of the oil film pushes up the shaft member, and the shaft member is supported by the oil film.
However, in the oil-impregnated bearing, the volume of internal pores provided in the sintered body is limited to about 30%, and the amount of lubricating oil that can be impregnated in the internal pores is limited. This pore has both a structure in which the lubricating oil can be vacuum-impregnated inside the sintered body and a structure in which the lubricating oil is self-circulated on the sliding surface, so that the pores on the surface of the sintered body are the same as the pores on the sliding surface. since a communicating structure, having air permeability. The pores having the air permeability, Ru constraints in the area of the load oil bearing can use Oh. In addition, the properties of the impregnated lubricating oil, such as viscosity and temperature dependency of viscosity, vapor pressure and temperature dependency of vapor pressure, degradation of lubricity due to thermal decomposition, and the like are directly reflected as properties of the sliding bearing.

Here, the load region to which the oil-impregnated bearing can be applied will be described. The load that the sliding surface receives from the shaft member is represented by the bearing surface pressure P and the sliding speed V of the shaft member. The bearing surface pressure P ranges from a surface pressure of 0.02 MPa in home appliances to 8 MPa in automobile parts. In addition, the sliding velocity V is up to 500m / min in vacuum cleaners and power tools from 1m / minute in audio and information equipment. Thus, the load that the bearing member receives from the shaft member covers a wide range according to the rotational force and the rotational speed of the shaft member.
However, it is said that the oil pressure of the sliding surface escapes due to air-permeable pores existing on the sliding surface, and the bearing surface pressure to which the oil-impregnated bearing can be applied is up to 1 MPa. Further, in high-speed rotation, the lubricating oil supplied to the sliding surface becomes too small due to air-permeable pores, and the sliding speed of the shaft member that can be applied with the oil-impregnated bearing is limited to 300 m / min. Among bearing devices mounted on automobiles, there is a bearing device that requires startability at −40 ° C. and continuous operation at a maximum sliding surface temperature of 250 ° C. When starting at a low temperature, the impregnated oil hardly oozes out on the sliding surface, so that seizure and adhesion of the sliding surface easily occur. In addition, since the viscosity of the lubricating oil is large at a low temperature start, the frictional force becomes excessive, and the rotational force of the shaft member is reduced. On the other hand, in high-temperature continuous operation, the impregnated oil tends to ooze out on the sliding surface, and the vapor pressure of the lubricating oil increases, and the impregnated oil is easily depleted. Alternatively, the thermal decomposition of the lubricating oil on the sliding surface proceeds, and the lubricity of the lubricating oil is impaired. In this way, there are restrictions on the area where the oil-impregnated bearing can be applied.

In the following, the friction coefficient of the lubricating oil in the sliding surface, illustrating the limits of the region where the oil bearing can adapt. When the lubricating oil that has exuded from the pores performs ideal fluid lubrication on the sliding surface, the friction coefficient is the product of the viscosity of the lubricating oil at the operating temperature, the rotational speed N of the shaft member, and the shaft diameter of the shaft member. Is divided by the product of the bearing surface pressure P and the clearance of the sliding contact surface .
The oil-impregnated bearing, the bearing surface pressure P reduces the rotational speed N of the shaft member is increased, the friction coefficient at the time of operation increases off al or ideal friction coefficient. That is, when the bearing surface pressure P increases during low-speed rotation, the bearing surface pressure P is liable to leak due to the air permeability of the pores, and the oil film does not exist on the sliding surface, so that the shaft member and the bearing member are in direct contact with each other. The friction of boundary lubrication becomes dominant, and seizure and adhesion on the sliding surface of the bearing member are likely to occur.
In order to expand the friction coefficient at which this boundary lubrication occurs to a region with a smaller friction coefficient, that is, to expand the fluid lubrication region, molybdenum disulfide MoS ₂ or graphite, which is a solid lubricant, is added to the sintered metal. (See, for example, Patent Documents 1 to 4), there is an effect that the area of fluid lubrication is somewhat widened, but there is a limit to the area where fluid lubrication spreads due to the air permeability of the pores on the sliding surface.
In addition, there is a case where a non-polar lubricating oil having a high adsorption activity and a bearing material having a high adsorption activity are combined (for example, see Non-Patent Documents 1 and 2). Even in this case, there is an effect that the fluid lubrication region is somewhat widened, but there is a limit to the region where the fluid lubrication is spread due to the air permeability of the pores on the sliding surface.

The problems of the oil-impregnated bearing described above are summarized as follows. First, when the bearing surface pressure increases due to an excessive axial load, the bearing surface pressure leaks from the pores of the sliding surface and the sliding surface reaches boundary lubrication. Accordingly, the life of the shaft member is short in applications where the rotational force of the shaft member is large. Second, when the shaft member rotates at a high speed, the force for drawing the lubricating oil to the sliding surface becomes strong, and the lubricating oil is easily depleted. Therefore, the service life is short in applications where the frequency of high-speed rotation is high. Third, when the shaft member rotates at a low speed, the force for drawing the lubricating oil to the sliding surface becomes weak, and boundary lubrication is likely to occur. Therefore, the service life is short in applications where the frequency of low-speed rotation is high. Fourth, at extremely low temperatures, the viscosity of the lubricating oil increases remarkably and the friction coefficient increases, and the rotational force of the shaft member during low temperature starting decreases. Fifth, low temperature operation makes it difficult to supply lubricating oil to the sliding surface, leading to boundary lubrication. Therefore, it cannot be used in applications that require startability at extremely low temperatures. Sixth, in high-temperature operation, the amount of lubricating oil supplied to the sliding surface becomes excessive, or the evaporation amount of the lubricating oil increases due to an increase in the vapor pressure of the lubricating oil, and the impregnated oil is depleted. Seventh, in high temperature operation, the thermal deterioration of the lubricating oil proceeds and the lubricating performance of the lubricating oil decreases. Therefore, the life is short in applications where the frequency of high-temperature operation is high.
Problems of such oil-impregnated bearing, since the principles of the sliding bearing in the oil-impregnated bearing is based on the lubricating oil property of being impregnated, fundamental solution is difficult. For this reason, rolling bearings are used in regions where oil-impregnated bearings cannot be applied. However, oil-impregnated bearings are required to have higher performance due to the trend toward downsizing and cost reduction of industrial equipment.

Japanese Patent Laid-Open No. 8-020836 JP-A-10-252756 JP 2001-279349 A JP 2008-202123 A

Mori, Masayuki, Relationship between solid surface activity and adsorption and boundary lubrication, lubrication, Vol. 33, no. 8 (1988), 585-590 Mori, Masayuki, Chemical properties of frictional new surfaces, tribologists, Vol. 38, no. 10 (1993), 884-889

Here, the general issues of bearing members are organized. Sliding bearings are superior to rolling bearings in terms of durability, quietness, small size, and low cost, but it is premised that an oil film of lubricating oil always exists on the sliding surface. If a lubrication device or lubrication mechanism for supplying lubricating oil to the sliding surface is provided, the bearing member becomes large and expensive like a dynamic pressure / hydrostatic bearing member. Moreover, the problem which arises from the property of lubricating oil cannot be solved. Meanwhile, oil bearing has an intractable problem based on the principle of to slip bearing. Therefore, a bearing member having a completely different concept from that of the conventional bearing, that is, a completely new member for supporting the rotation and load of the shaft member is required. If this new member that supports the rotation and load of the shaft member has the following properties, it can be used for various industrial machines as an innovative bearing device, and it can respond to miniaturization and cost reduction in industrial equipment. it can.
First, this member is different from conventional rolling elements and lubricating oil films. Second, this member does not cause seizure or adhesion to the bearing member. Third, the frictional force by this member is small. Fourth, this member does not attack the bearing member. Fifth, this member does not break even if it receives a large load from the shaft member. Sixth, this member exists semi-permanently in the gap between the shaft member and the bearing member. Seventh, this member is not affected by the rotational speed of the shaft member. Eighth, this member is not affected by operating temperature. Ninth, this member can produce a member that supports the rotation and load of the shaft member by the same means for any size shaft member or bearing member. Tenth, this member can be manufactured inexpensively.

A shaft member for rotation in a bearing device consisting of a sliding bearing member shaft portion of the shaft member has a slidable sliding surface, the shaft member is either magnetite or maghemite in the surface of the shaft portion having a magnetic a shaft member granular particles are evenly magnetic attraction comprised of Kano material, the first feature section of the manufacturing method of manufacturing a shaft member, an organic iron compound to produce the iron oxide FeO by pyrolysis, in an organic solvent Disperse to prepare a dispersion, and immerse the shaft portion of each shaft member in the group of shaft members in the dispersion of the organic iron compound, and bring the dispersion of the organic iron compound into contact with the surface of the shaft portion. Thereafter, the temperature of the dispersion is raised to vaporize the organic solvent, the organic iron compound is adsorbed to the shaft portion of the shaft member, and the assembly of the shaft members is heat-treated in the atmosphere, and the organic Heat content of iron compounds The iron oxide FeO is deposited on the surface of the shaft portion, and the temperature is further raised to oxidize the iron oxide FeO to magnetite or maghemite, whereby the shaft portion of each shaft member in the group of shaft members. This is a method of manufacturing a shaft member in which a collection of shaft members in which granular fine particles made of either a magnetite or maghemite material are uniformly magnetically adsorbed on the surface is manufactured .

In other words, according to the first feature means, either one of magnetite or maghemite is applied to the shaft portion of the shaft member made up of a large number of shaft members in one manufacturing tact consisting of four extremely simple continuous processes. The particulate fine particles made of these materials are evenly magnetically adsorbed. As a result, for a large collection of shaft members, a shaft member in which particulate fine particles made of either magnetite or maghemite are magnetically adsorbed on the shaft portion of the shaft member can be manufactured at a low manufacturing cost. The shaft member having the tenth property of the ten items is manufactured.
That is, first, an organic iron compound is filled in a container, and an organic solvent is added thereto and stirred. Thereby, a dispersion liquid in which the organic iron compound is dispersed in the organic solvent can be prepared. Next, the shaft portion of each shaft member made up of a collection of shaft members is immersed in the container. As a result, the dispersion of the organic iron compound comes into contact with each shaft portion. Furthermore, the temperature of the container is raised to the boiling point of the organic solvent. Thereby, the organic iron compound is adsorbed on the shaft portions of all the shaft members. Next, in an air atmosphere, the temperature of the container is raised to a temperature at which the organic iron compound is thermally decomposed. As a result, a collection of granular iron oxide FeO fine particles is deposited on the shaft portions of all the shaft members. Thereafter, the temperature of the container is raised to a temperature at which the reaction of iron oxide FeO oxidizing magnetite or magnetite proceeds. As a result, a collection of granular fine particles composed of magnetite or maghemite is magnetically adsorbed on the surface of the shaft portion of all shaft members.
That is, in this shaft member manufacturing method, the organic iron compound adsorbed on the shaft portion of the shaft member is thermally decomposed to precipitate particulate fine particles made of iron oxide FeO and oxidize iron oxide FeO. _The particulate fine particles made of any material of ₃ O ₄ or maghemite γ-Fe ₂ O ₃ are uniformly deposited on the surface of the shaft portion and magnetically adsorbed. For this reason, in any shaft part of the shaft member having any size, granular fine particles made of magnetite or maghemite are magnetically adsorbed on the surface of the shaft part by the same means. Thus, the shaft member having the ninth property described in the ninth paragraph is manufactured. Furthermore, magnetite or maghemite particulate fine particles can be magnetically adsorbed to the shaft portion of the shaft member by an extremely simple means by simply heat-treating the organic iron compound in the atmosphere. For this reason, a shaft member having the tenth property described in the ninth paragraph is manufactured.
That is, when an organic iron compound that generates iron oxide FeO by thermal decomposition is dispersed in a solvent, the shaft portion of the shaft member is immersed in this dispersion, and then the solvent is vaporized, an organic material is formed on the surface of the shaft portion of the shaft member. Iron compounds are adsorbed. This shaft member is heat-treated in an air atmosphere. When the heat treatment temperature exceeds the boiling point of the organic substance constituting the organic iron compound, it thermally decomposes into the organic substance and iron oxide FeO. When the heat treatment temperature is further increased, the organic matter is vaporized by taking the heat of vaporization. On the other hand, in the iron oxide FeO, the oxidation reaction in which the divalent iron ion Fe ²⁺ becomes the trivalent iron ion Fe ³⁺ proceeds as the temperature rises. In the oxidation reaction of the divalent iron ions ^{Fe 2+} is trivalent iron ions ^{Fe 3+,} divalent iron ions ^{Fe 2+} constituting the iron oxide FeO is turned trivalent iron ions ^{Fe 3+,} becomes magnetite . That is, the divalent iron ion Fe ²⁺ constituting the iron oxide FeO becomes the trivalent iron ion Fe ³⁺ to become Fe ₂ O ₃ , and the composition formula becomes magnetite Fe ₃ O ₄ with FeO · Fe ₂ O _3. . Since the oxidation reaction in which the divalent iron ions Fe ²⁺ become trivalent iron ions Fe ³⁺ proceeds on the surface of the shaft portion of the shaft member, the magnetite Fe ₃ O ₄ is formed as particulate fine particles on the surface of the shaft portion of the shaft member. Deposits evenly and magnetically adsorbs. This is because the organic iron compound is adsorbed on the surface of the shaft portion.
When the temperature is further increased , all of the divalent iron ions Fe ²⁺ in FeO constituting the magnetite FeO · Fe ₂ O ₃ become trivalent iron ions Fe ³⁺ to form iron oxide Fe ₂ O ₃ . Since this iron oxide Fe ₂ O ₃ has a cubic crystal structure similar to that of magnetite Fe ₃ O ₄ , the iron oxide Fe ₂ O ₃ becomes gamma phase maghemite γ-Fe ₂ O ₃ . When the oxidation reaction in which the divalent iron ion Fe ²⁺ in the magnetite FeO · Fe ₂ O ₃ is ^converted to the trivalent iron ion Fe ³⁺ is completed, the maghemite γ-Fe ₂ O ₃ is granular on the surface of the shaft portion. As a uniform deposit and magnetic adsorption.
In addition, since maghemite produced | generated by the thermal decomposition of an organic iron compound is produced | generated by the oxidation of iron oxide FeO, it precipitates as a granular particle instead of an acicular particle | grain. In the prior art, maghemite γ-Fe ₂ O ₃ is produced as acicular particles. That is, when an atmosphere is sent to an alkaline aqueous solution of ferrous sulfate or ferric sulfate and reacted, iron hydroxide α-FeOOH called goethite, which is acicular particles, precipitates. Goethite is once dehydrated in an atmosphere of hydrogen gas to hematite α-Fe ₂ O ₃ and further reduced to produce magnetite Fe ₃ O ₄ . Thereafter, when the magnetite is slowly heated and oxidized in the air, the mitite particles are formed into acicular mag. Maghemite composed of acicular particles is not suitable as a ferromagnetic fine particle to be magnetically attracted to the shaft portion because it is difficult to slip on the sliding surface of the bearing member. In addition, the manufacturing process for depositing mitite particles into needle-shaped mags requires more complex manufacturing processes than the process for depositing mitite particles into granular mags only by heat treatment of organic iron compounds. Expensive.
On the other hand, magnetite Fe ₃ O ₄ or maghemite γ-Fe ₂ O ₃ has a ferrimagnetic property that is ferromagnetic. As a result, the particulate fine particles made of magnetite or maghemite are magnetically attracted to each other, and are further magnetically attracted to the shaft portion of the shaft member having magnetism. Furthermore, the magnetic Curie point of magnetite is 585 ° C., and the magnetic Curie point of maghemite is 675 ° C. On the other hand, the sliding surface of a sliding bearing of an automobile part rises to 250 ° C. when continuous operation at a high temperature continues. Since the magnetic Curie point of magnetite or maghemite is 300 ° C. higher than the maximum temperature of the sliding surface of the sliding bearing, the magnetic attractive force between the ferromagnetic fine particles and the magnetic attractive force on the shaft member are almost the same as normal temperature. Furthermore, even at an extremely low temperature of −40 ° C., the magnetic attractive force between the ferromagnetic fine particles and the magnetic attractive force on the shaft member are almost the same as those at room temperature. For this reason, the frictional force generated when the ferromagnetic fine particles are in contact with the sliding surface at an extremely low temperature does not increase. Therefore, at all operating temperatures of the bearing device, the ferromagnetic granular fine particles are magnetically attracted to each other and magnetically attracted to the shaft member, and stably support the rotation and load of the shaft member in the same state as normal temperature. As a result, the shaft member having the eighth property described in the ninth paragraph is manufactured.
Maghemite undergoes phase transition to hematite α-Fe ₂ O ₃ which is an alpha phase of iron oxide Fe ₂ O ₃ at a temperature of 450 ° C. or higher in the atmosphere . Because hematite is not ferrimagnetic but weakly ferromagnetic, the magnetic attraction between hematite particles and the magnetic attraction to the shaft member are reduced, and hematite may fall off the surface of the shaft when the shaft member is in operation. is there. However, since the maximum temperature when the shaft member is in sliding contact with the sliding surface of the bearing member is about 250 ° C., the phase transition of the magnet to the mag does not occur.
Here, the excellent effect of the shaft member in which the particulate fine particles made of either magnetite or maghemite are uniformly adsorbed on the surface of the shaft portion of the shaft member having magnetism in the present characteristic means will be described. Uniformly magnetic attraction magnetite or maghemite granular particles on the surface of the shaft portion of the shaft member having a magnetism, because that slides sliding surface of the bearing member, the granular particles of magnetite or maghemite are, the rotation of the shaft member and the load To support. Bearing device entirely made of new concept of this, that is, the bearing device granular particulates uniformly magnetic adsorbed was magnetite or maghemite in the surface of the shaft portion of the shaft member, to slide a sliding surface of the bearing member having a magnetism, the following ideas It is a bearing device based on. As described in the third to sixth paragraphs and the ninth paragraph, the problems of the conventional rolling bearing and the sliding bearing are the members that support the rotation and load of the shaft member provided on the bearing member, that is, the rolling element and It generated in the oil film of the lubricating oil. Therefore, in order to fundamentally solve the problem of the conventional bearing device, there is no other way but to exclude the member that supports the rotation and load of the shaft member from the bearing member. For this reason, it was thought that the problem of the conventional bearing device could be fundamentally solved by excluding the member supporting the rotation and load of the shaft member from the bearing member and providing the shaft member. To realize this idea as a bearing device, a new member provided on the shaft member that supports the rotation and load of the shaft member must have the properties of the ten items described in the ninth paragraph. In order to combine these properties, the magnetite or maghemite particulates are magnetically adsorbed evenly on the surface of the shaft part of the shaft member, and the magnetite or maghemite particulate particulates have a completely new structure that slides on the sliding surface of the bearing member. A bearing device was obtained. As will be described below, this bearing device has the first to seventh properties described in the ninth paragraph, and can fundamentally solve the problems of conventional rolling bearings and sliding bearings.
In other words, when the magnetite or maghemite particulates magnetically adsorbed on the rotating shaft contact the sliding surface of the bearing member, the magnetite or maghemite particulates load the shaft and load in the direction of the inertial force of the rotating shaft. Receive as. This load is greater than the magnetic attraction force of the granular fine particles of magnetite or maghemite, it is smaller than the magnetic attraction force between the granular particles and the shaft portion of the magnetite or maghemite. On the other hand, the load that the magnetite or maghemite particulates receive from the shaft is the direction of the inertial force due to the rotation of the shaft, and since this inertial force is the tangential direction of the rotation of the shaft, the magnetite or maghemite that receives the load Granular particles slide on the sliding surface. For this reason, the granular fine particles of magnetite or maghemite do not attack the sliding surface. Further, the load received by the granular particles of magnetite or maghemite is converted into energy granular particles of magnetite or maghemite slips. Further, when the magnetite or maghemite particulate particles slide, the sliding particles are fine particles, so that the magnetite or maghemite particulate particulates and the adjacent magnetite or maghemite particulate particulates are newly in contact with the sliding surface, and the rotating shaft portion is rotated. It receives a load in the direction of inertial force and slides on the sliding surface as well. The new magnetite or maghemite particulates do not attack the sliding surface by sliding on the sliding surface. At this time, the load received by the magnetite or maghemite particulate fine particles from the shaft portion is converted into energy that slides due to the slide of the magnetite or maghemite particulate fine particles, and becomes a smaller load. Such a continuous phenomenon in which the granular fine particles of magnetite or maghemite slide on the sliding surface continuously occurs until the load received from the shaft member becomes smaller than the magnetic adsorption force between the granular fine particles of magnetite or maghemite . However, the magnetite or maghemite particulate fine particles slide on the sliding surface, and the magnetite or maghemite particulate fine particles do not attack the sliding surface. In addition, since the magnetite or maghemite particulates slide, the magnetite or maghemite particulates are not destroyed.
The size of the granular fine particles of magnetite or maghemite is smaller than the roughness of the sliding surface and is smaller than submicron. Therefore, until the load received from the shaft member is smaller than the magnetic attraction force of the granular fine particles of magnetite or maghemite, sliding in contact with magnetite or granular particles slip surface maghemite continuously. In addition, the size of the magnetite or maghemite particulate particles is sufficiently smaller than the gap formed by the shaft portion and the sliding surface. Therefore, uniformly magnetic adsorbed magnetite or maghemite granular particles on the surface of the shaft portion, the granular particles of magnetite or maghemite are randomly sliding surface and in contact, undergo continuous load granular particles of a particular magnetite or maghemite No, magnetite or maghemite particulates are not damaged.
In addition, when the magnetite or maghemite granular fine particles are in contact with the sliding surface, the axial load is applied in the direction of the inertial force acting on the rotating shaft, but the magnetite or maghemite granular fine particles are granular fine particles. The load is received by a contact close to a point contact where the area to receive the load is minute. Moreover, the load of the shaft portion which receives the granular particles of magnetite or maghemite is converted into energy granular particles of magnetite or maghemite slips. Friction force generated when magnetite or maghemite particulates come into contact with the sliding surface is generated according to the contact area and load size, so the friction force is small, and unnecessary wear, heat and sound due to contact do not occur. . Further, the granular particles of magnetite or maghemite, since slipping immediately after contacting the sliding surface in contact close to point contact, seizure and adhesion at the sliding surface does not occur.
Further, when the magnetite or maghemite granular fine particles slide, they instantaneously deviate slightly from the magnetic adsorption of the magnetite or maghemite granular fine particles. Alternatively, even when the shaft member rotates at high speed, the granular fine particles of magnetite or maghemite are slightly separated from the magnetic adsorption of the granular fine particles of magnetite or maghemite for a moment. However, the gap formed by the shaft and the sliding surface is narrow, and there is always a magnetic force generated by innumerable magnetite or maghemite particulates magnetically adsorbed on the shaft, and the magnetic attraction force with the shaft Therefore, the magnetite or maghemite particulates slightly separated from the magnetic adsorption are instantaneously magnetically adsorbed again with the magnetite or maghemite particulates . In this way, the magnetite or maghemite particulates are magnetically adsorbed regardless of the rotation speed of the shaft member, and the magnetite or maghemite particulates are maintained in a state of being magnetically attracted to the shaft portion. Supports rotation and load. Further, since the particulate fine particles of magnetite or maghemite are solid, they do not evaporate. Therefore, granular particles of magnetite or maghemite, permanently magnetically adsorbed to the shaft member.
As described above, the shaft member in which magnetite or maghemite particulate particles are uniformly magnetically adsorbed on the surface of the shaft portion having magnetism is a property necessary for supporting the rotation and load of the shaft member described in the ninth paragraph. Of these, the first to seventh properties are combined. As a result, the shaft member in which magnetite or maghemite particulates are magnetically adsorbed on the surface of the shaft portion has all the properties of the ten items described in the ninth paragraph.
In addition, as for the material of the shaft member, conventionally, the carbon content of the carbon steel for machine structure is S25C to S45C in which the carbon content is 0.25 wt % to 0.45 wt %, or the carbon steel having a carbon content of 0.45 wt % or more Or alloy steels, such as nickel chromium steel, nickel chromium molybdenum steel, chromium steel, chromium molybdenum steel, are used. In a special bearing device that requires chemical resistance, the shaft member is made of martensitic stainless steel. Since these shaft members all have ferromagnetic properties, if the shaft member is formed of a conventional material, magnetite or maghemite particulate particles are uniformly magnetically adsorbed on the surface of the shaft portion. In addition, the material of the parts that make up the sliding surface of the bearing member has conventionally been copper alloys such as brass and bronze, tin copper alloys called bavit metal, tin antimony copper alloys, lead antimony tin alloys, and copper lead alloys called kelmets. Alternatively, cadmium alloy, aluminum alloy, or synthetic resin is used. Since these materials are non-magnetic, magnetite or maghemite particulates are not magnetically adsorbed on the sliding surface. Therefore, a portion of the particulate particles of magnetite or maghemite is moved sliding surface and magnetic attraction, thereby, inhibited the phenomenon in which the magnetic adsorption magnetite or maghemite granular particles of slipping on the shaft portion, the non-slip magnetite or The slip surface is not attacked by the granular particles of maghemite . Therefore, the sliding surface may be made of a conventional material. Thus, the shaft member and the bearing member may be made of conventional materials, and no particularly expensive material is required at all.
Further, the fitting tolerance between the shaft member and the bearing member is that the inner diameter tolerance of the sliding surface is H7 and the outer diameter tolerance of the shaft portion is f6 or e6, so that at least 25 microns is provided between the shaft portion and the sliding surface. A gap is formed. On the other hand, the granular fine particles of magnetite or maghemite that are magnetically adsorbed to the shaft portion of the shaft member are smaller than submicrons. For this reason, when the bearing member is assembled to the shaft member, magnetite or maghemite particulate particles are not peeled off from the shaft portion.

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Second feature means of a method of manufacturing a shaft member, an organic iron compound to produce the iron oxide FeO pyrolysis as described in the first feature means is an organic iron compound which iron ions are coordinately bound to oxygen ions, the A method of manufacturing a shaft member, wherein an organic iron compound is used as an organic iron compound that generates iron oxide FeO by thermal decomposition in the first characteristic means, and a group of shaft members is manufactured in accordance with the method described in the first characteristic means. There is in point.

That is, according to this characteristic means , iron oxide FeO is produced when an organic iron compound in which iron ions coordinate with oxygen ions forming a ligand is thermally decomposed in the atmosphere, and further, iron oxide FeO is oxidized. Then, magnetite Fe ₃ O ₄ or magnetite γ-Fe ₂ O ₃ is precipitated. That is, in such a thermal decomposition reaction of the organic iron compound in the atmosphere, thermal decomposition starts when the boiling point of the organic substance constituting the organic iron compound is exceeded, and decomposes into iron oxide FeO and the organic substance. That is, the oxygen ion constituting the organic iron compound becomes a ligand and coordinates with the iron ion so that the distance between the iron ion and the oxygen ion that is the ligand is short. Therefore, in the thermal decomposition of an organic iron compound, a short distance region of the opposite side of the binding sites of the oxygen ions is ligand binds to iron ions, i.e., the bond distance is long site expires first. As a result, the organic iron compound is decomposed into iron oxide FeO in which iron ions are combined with oxygen ions and organic matter. After this, the organic matter is vaporized by taking the heat of vaporization. On the other hand, the iron oxide FeO undergoes an oxidation reaction in which the divalent iron ion Fe ²⁺ becomes the trivalent iron ion Fe ³⁺ as the temperature rises, and the iron oxide FeO has a composition formula of FeO · Fe ₂ O _{3 and} is magnetite Fe ₃ O. ₄ When the temperature is further increased, the divalent iron ion Fe ²⁺ in the FeO constituting the magnetite FeO · Fe ₂ O ₃ becomes the trivalent iron ion Fe ³⁺ to form a gamma phase of iron oxide Fe ₂ O ₃ , that is, maghemite. It becomes γ-Fe ₂ O ₃ . In this way, by the oxidation reaction of iron oxide FeO, magnetite stones Might is deposited to the mug. As a result, the particulate fine particles made of magnetite or maghemite are magnetically adsorbed on the surface of the shaft member having magnetism.

The third feature means of a method of manufacturing a shaft member, an organic iron compound which iron ions in the second feature means for oxygen ions and coordination bonds, iron acetate, benzoate, iron, caprylic iron, any of the iron naphthenate An organic iron compound of iron carboxylate or acetylacetone iron, and using the organic iron compound as the organic iron compound in the second characteristic means, a group of shaft members is manufactured according to the method described in the second characteristic means It lies in the fact Ru manufacturing method der.

According to this feature means, iron acetate Fe (CH ₃ COO) ₂ , iron benzoate Fe (C ₆ H ₅ COO) ₂ , iron caprylate Fe (CH ₃ (CH ₂ ) ₆ COO) ₂ , or iron naphthenate In any of the iron carboxylates composed of Fe (C ₆ H ₅ COO) ₂ or the like, the oxygen ions constituting the carboxyl group COOH of the carboxylic acid become ligands and approach the divalent iron ions, and the oxygen ions are 2 Coordinates with a valent iron ion. Further, acetylacetone iron Fe (C ₅ H ₇ O ₂ ) ₃ has a ligand formed by oxygen ions constituting acetylacetonate C ₅ H ₇ O ₂ ^— which is a conjugate base of acetylacetone C ₅ H ₈ O _2. It is an organic iron compound in which acetylacetonate forms a six-membered ring by coordination with iron ions. Such thermal decomposition reaction in iron carboxylate or acetylacetone iron starts thermal decomposition when the boiling point of carboxylic acid or acetylacetone is exceeded, and decomposes into iron oxide FeO and carboxylic acid or acetylacetone. In other words, the oxygen ion constituting the carboxyl group of the carboxylic acid or the oxygen ion constituting the acetylacetonate is coordinated to approach the iron ion, so the distance between the iron ion and the oxygen ion that is the ligand is short. . For this reason, in thermal decomposition, the site | part of the long distance of the opposite side where the oxygen ion which is a ligand couple | bonds with an iron ion cuts first. As a result, iron ions are decomposed into iron oxide FeO combined with oxygen ions and carboxylic acid or acetylacetone. Thereafter, the carboxylic acid or acetylacetone vaporizes by taking the heat of vaporization. On the other hand, the iron oxide FeO undergoes an oxidation reaction in which the divalent iron ion Fe ²⁺ becomes the trivalent iron ion Fe ³⁺ as the temperature rises, and the iron oxide FeO has a magnetite Fe ₃ O composition of FeO · Fe ₂ O _{3. 4} When the temperature is further raised, the divalent iron ion Fe ²⁺ in the FeO constituting the magnetite FeO · Fe ₂ O ₃ becomes the trivalent iron ion Fe ^3+, and the gamma phase of the iron oxide Fe ₂ O ₃ , that is, into the mag It becomes mit γ-Fe ₂ O ₃ . Thus, magnetite or magnetite is precipitated by the oxidation reaction of iron oxide FeO. Thereby, the particulate fine particles made of magnetite or maghemite are magnetically adsorbed on the surface of the shaft portion of the shaft member having magnetism.
The above-mentioned iron carboxylate or iron acetylacetone is an industrial chemical that is easy to synthesize and inexpensive because it is a compound of general-purpose carboxylic acid or general-purpose organic matter and iron. A cheap industrial chemical is adsorbed on the shaft part of the shaft member, and magnetite or magnetite particulate fine particles are magnetically adsorbed on the shaft part of the shaft member simply by heat-treating the shaft member in the atmosphere. A new bearing device can be manufactured at low cost. For this reason, this feature means can realize a bearing device having all the properties of the ten items described in the ninth paragraph.

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It is a figure explaining the manufacturing process which magnetically adsorbs ferromagnetic fine particles on the surface of a shaft part using an organic iron compound. It is a figure explaining the process of magnetically adsorbing magnetite fine particles on the surface of a shaft part using iron naphthenate.

Embodiment 1
Embodiment 1 is an embodiment in which an organic iron compound that generates iron oxide FeO by thermal decomposition is used as a raw material, and a shaft member in which ferromagnetic fine particles are uniformly magnetically adsorbed on the surface of the shaft portion of the shaft member is manufactured. A dispersion in which the organic iron compound is previously dispersed in n-butanol as 8% by weight is prepared, and the n-butanol dispersion of the organic iron compound is filled in a container. And the axial part of the axial member which consists of a collection of axial members is immersed in the n-butanol dispersion liquid of an organic iron compound for a fixed time. Thereby, the n-butanol dispersion of the organic iron compound comes into contact with the surface of the shaft portion.
Next, the container is continuously subjected to the heat treatment shown in FIG. First, the container enters a low-temperature baking chamber A set at 120 ° C. for a certain period of time, n-butanol in the n-butanol dispersion of the organic iron compound is vaporized, and the vaporized n-butanol is recovered by the recovery machine C. Thereby, the organic iron compound is adsorbed on the surface of the shaft portion. Further, the container enters the high temperature baking chamber B. The high temperature baking chamber B includes a low temperature baking part B1 set to a relatively low temperature and a high temperature baking part B2 set to a relatively high temperature. The low-temperature calcining part B1 is heated to a temperature slightly higher than the boiling point of the organic substance constituting the organic iron compound, and thereafter maintained at this temperature for a certain time. When the container enters the low temperature firing part B1, the organic iron compound adsorbed on the surface of the shaft part is thermally decomposed into an organic substance and iron oxide FeO . As a result, iron oxide FeO is deposited on the surface of the shaft portion. The organic matter produced by the thermal decomposition is collected by the organic matter collecting machine D. The high-temperature fired portion B2 is heated to a temperature at which the iron oxide FeO is oxidized to magnetite or maghemite, and then held at this temperature for a certain time. When the container enters the high-temperature firing part B2, iron oxide FeO is oxidized to magnetite or maghemite, and thereby, the particulate fine particles made of magnetite or maghemite are magnetically adsorbed evenly on the surface of the shaft part.
As described above, the manufacturing process for manufacturing the shaft member in which the particulate fine particles made of magnetite or maghemite are magnetically adsorbed uniformly on the surface of the shaft portion of the shaft member is performed in the n-butanol dispersion of the organic iron compound. The step of immersing the shaft portion of the shaft member made of a group of the above and the step of heat-treating the group of shaft members in the air atmosphere are continuously performed. Moreover, the process of heat-treating the shaft member includes three consecutive heat treatment processes. Since it is manufactured by such a simple continuous process, a collection of shaft members in which particulate fine particles made of magnetite or maghemite are uniformly adsorbed on the shaft portion of the shaft member can be manufactured at a very low manufacturing cost.

Embodiment 2
The second embodiment uses iron naphthenate Fe (C ₆ H ₅ COO) ₂ which is a kind of iron carboxylate as the organic iron compound in the first embodiment, and the shaft on which the magnetite particles are uniformly magnetically adsorbed on the surface of the shaft portion. It is embodiment which manufactures a member. Iron naphthenate is an iron carboxylate that is easily synthesized by the reaction of two molecules of naphthenic acid C ₆ H ₅ COOH with iron. That is, the hydrogen ion of the carboxyl group COOH constituting naphthenic acid is easily separated, and the divalent iron ion is synthesized at the site of the oxygen ion bonded to the separated hydrogen ion, and the structural formula is it is an inexpensive iron carboxylate compound represented by _{C 6 H 5 COO-Fe-} OOCC 6 H 5.
FIG. 2 shows a manufacturing process for manufacturing a shaft member in which magnetite granular fine particles are uniformly magnetically adsorbed on the surface of the shaft portion of the shaft member. First, a collection of iron naphthenate and a shaft member is prepared (step S10). The shaft member is a kind of structural carbon steel and has carbon atoms of 0.25 Vol. % Of S25C. The shaft member is not limited to S25C, and carbon steel having a carbon content of 0.25% by weight or more, nickel chrome steel, nickel chrome molybdenum steel, chrome steel, chrome molybdenum steel, etc. according to the rotational force of the bearing member. Alloy steel may be selected. Next, iron naphthenate is weighed to a ratio of 8% by weight with respect to n-butanol, and iron naphthenate is mixed with n-butanol and stirred to prepare an n-butanol dispersion of iron naphthenate. The container is filled with this dispersion (step S11). Further, the shaft portion is immersed in the n-butanol dispersion of iron naphthenate while separating the shaft members from each other (step S12). Next, the container containing the dispersion liquid is placed in a heat treatment furnace in an air atmosphere. First, the container enters the low-temperature baking chamber A at 120 ° C. for 5 minutes, n-butanol is vaporized, and the vaporized n-butanol is collected by the collecting machine C (step S13). As a result, iron naphthenate is adsorbed on the surfaces of the shaft portions of all the bearing members. Next, the container enters the high-temperature baking chamber B, and two-stage baking is performed. The low-temperature fired portion B1 is heated to 300 ° C. at a temperature rising rate of 10 ° C./min, and held at 300 ° C. for 10 minutes. The shaft member that entered the low-temperature firing chamber B1 was thermally decomposed by naphthenic acid iron adsorbed on the shaft portion of the shaft member into naphthenic acid and iron oxide FeO, and the naphthenic acid generated by pyrolysis was completely vaporized and vaporized. Naphthenic acid is recovered by the recovery machine D (step S14). Thereafter, the shaft member enters the high-temperature firing part B2. The high-temperature fired portion B2 is heated from 300 ° C. to 350 ° C. at a temperature rising rate of 1 ° C./min and held at 350 ° C. for 30 minutes. In the shaft member that has entered the high-temperature fired portion B2, iron oxide FeO deposited on the shaft portion is oxidized to magnetite Fe ₃ O ₄ , and the generated particulate fine particles made of magnetite are evenly magnetically adsorbed on the surface of the shaft portion (S15). Process). Thus, the surfaces of the shaft portions of all shaft members are uniformly covered with the magnetite granular fine particles. Finally, a collection of shaft members is taken out from the container (step S16).
Magnetite fine particles are magnetically adsorbed to the entire surface of the shaft portion of the shaft member, and magnetite fine particles are magnetically adsorbed in addition to the surface of the shaft portion that is in sliding contact with the sliding surface of the bearing member which is originally required. In this case, the magnet may be brought close to unnecessary magnetite fine particles, and the magnetite fine particles may be removed by magnetic adsorption. Since the magnetite fine particles magnetically adsorbed on the shaft portion of the shaft member are smaller than the submicron size, even if such fine particles fall off the shaft portion when the shaft member rotates at high speed, there is little problem as a bearing device.

Embodiment 3
Embodiment 3 uses the iron naphthenate _{Fe (C 6 H 5 COO)} 2 in the second embodiment was uniformly magnetically attracted to the shank surface granulated particles of chromite _gamma-Fe 2 _{O 3} to the mug of the shaft member It is embodiment which manufactures a shaft member. In addition, since this embodiment oxidizes iron oxide FeO to magite, the temperature conditions in the high-temperature firing part B2 for oxidizing iron oxide FeO to magnetite in the step S15 in the above-described embodiment 2 are different, and other steps are The same as in the second embodiment.
First, a collection of iron naphthenate and a shaft member is prepared (corresponding to step S10). The shaft member is a kind of structural carbon steel, and the carbon atoms are 0.25 Vol. % Of S25C. Next, iron naphthenate is weighed to a ratio of 8% by weight with respect to n-butanol, and iron naphthenate is mixed with n-butanol and stirred to prepare an n-butanol dispersion of iron naphthenate. The dispersion is filled in a container (corresponding to step S11). Furthermore, the shaft portion is immersed in the n-butanol dispersion of iron naphthenate while separating the shaft members from each other (corresponding to step S12). Next, the container containing the dispersion is placed in a heat treatment furnace in an air atmosphere. First, the container enters the low-temperature baking chamber A at 120 ° C. for 5 minutes, n-butanol is vaporized, and the vaporized n-butanol is collected by the collecting machine C (corresponding to step S13). As a result, iron naphthenate is adsorbed on the surfaces of the shaft portions of all the bearing members. Next, the container enters the high temperature baking chamber B. The low-temperature fired part B1 is heated to 300 ° C. at a temperature rising rate of 10 ° C./min, and held at 300 ° C. for 10 minutes. The shaft member that entered the low-temperature firing chamber B1 was thermally decomposed by naphthenic acid iron adsorbed on the shaft portion of the shaft member into naphthenic acid and iron oxide FeO, and the naphthenic acid generated by the thermal decomposition was completely vaporized and vaporized. Naphthenic acid is recovered by the recovery machine D (corresponding to step S14). After this, the container enters the high temperature firing section B2. The high-temperature fired portion B2 is heated from 300 ° C. to 400 ° C. at a temperature rising rate of 1 ° C./min and held at 400 ° C. for 30 minutes. In the shaft member entering the high-temperature fired portion B2, iron oxide FeO deposited on the shaft portion is oxidized into maghemite, and the generated particulate fine particles made of maghemite are magnetically adsorbed evenly on the surface of the shaft portion (S15). Equivalent to the process). Thus, the surfaces of the shaft portions of all the shaft members are uniformly covered with the granular fine particles of maghemite. Finally, a collection of shaft members is taken out from the container (corresponding to step S16).
As described in the second embodiment, the fine particles of magnetite are magnetically adsorbed on the entire surface of the shaft portion of the shaft member, and in addition to the surface of the shaft portion that is slidably in contact with the sliding surface of the bearing member, which is originally required, the magnet may If it becomes a problem that the fine particles are magnetically adsorbed, the magnet may be brought close to the unnecessary magite fine particles, and the fine particles may be removed by magnetic adsorption.

Example 1
Example 1 is an example according to Embodiment 2 in which magnetite fine particles are uniformly magnetically adsorbed on the surface of the shaft portion of the shaft member using iron naphthenate.
First, iron naphthenate as a raw material, n-butanol as a solvent, and a shaft member are prepared. As iron naphthenate, iron naphthenate commercially available as a metal soap (for example, a product of Toei Chemical Co., Ltd.) was used. For n-butanol, a reagent first grade was used. The shaft member is a kind of structural carbon steel and has carbon atoms of 0.25 Vol. % S25C.
Next, iron naphthenate is weighed so as to have a ratio of 8% by weight with respect to n-butanol, and this iron naphthenate is mixed with n-butanol and stirred to prepare an n-butanol dispersion of iron naphthenate. did. The dispersion was filled in a container, and the shaft members were immersed in an n-butanol dispersion of iron naphthenate while the shaft members were separated from each other. In addition, prepare a jig with a large number of holes in a disk-shaped plate, place a shaft member in the hole of this jig, and place this jig in a container containing n-butanol dispersion of iron naphthenate. By arrange | positioning, the axial part of a shaft member is immersed in the n-butanol dispersion of iron naphthenate.
Furthermore, the container was placed in a heat treatment furnace in an air atmosphere for heat treatment. First, the container was allowed to stand at 120 ° C. for 5 minutes to vaporize n-butanol, and the vaporized n-butanol was recovered by a recovery machine. After n-butanol is vaporized, iron naphthenate is adsorbed on the surface of the shaft portion of all shaft members. Next, the temperature was raised from 120 ° C. to 300 ° C. at a temperature rising rate of 10 ° C./min, and further left to stand at 300 ° C. for 10 minutes to thermally decompose iron naphthenate into naphthenic acid and iron oxide FeO. Naphthenic acid produced by pyrolysis was vaporized, and the vaporized naphthenic acid was recovered by a recovery machine. Thereafter, the temperature is increased from 300 ° C. to 350 ° C. at a rate of 1 ° C./min, and further left at 350 ° C. for 30 minutes to oxidize iron oxide FeO generated by pyrolysis to magnetite Fe ₃ O _4. It was. Finally, a collection of shaft members on which magnetite fine particles were magnetically adsorbed was taken out of the jig.
Next, the shaft portion of the shaft member manufactured under the above conditions was observed, and it was observed whether the target magnetite fine particles were reliably magnetically adsorbed on the surface of the shaft portion. First, a part of the shaft portion was taken out as a sample from the surface of the shaft portion, and the sample was observed with an electron microscope. The electron microscope used was an ultra-low acceleration voltage SEM from JFE Techno-Research Corporation. This apparatus is capable of observing the surface with an extremely low acceleration voltage from 100 V, and further has a feature that the surface of the sample can be directly observed without forming a conductive film on the sample. A secondary electron beam between 900-1 kV of the reflected electron beam was taken out, image processing was performed, and the unevenness of the sample surface was observed. It was confirmed that an extremely large number of granular fine particles having a size of 40-60 nm were uniformly adsorbed on the entire surface of the sample. Next, the energy and intensity of characteristic X-rays were subjected to image processing, and the types of elements constituting the particulate particles adsorbed on the sample surface and their distribution states were analyzed. Both iron atoms and oxygen atoms were present uniformly on the surface, and no particularly uneven locations were found. Thus, it was confirmed that particulate fine particles made of iron oxide were adsorbed. Furthermore, an EBSP analysis function was added to the function of the extremely low acceleration voltage SEM, and the crystal structure was analyzed. From this result, it was confirmed that the particulate fine particles adsorbed on the entire surface of the sample were magnetite. The EBSP analysis function means that when a sample is irradiated with an electron beam, reflected electrons are diffracted by the atomic plane in the sample to form a band-like pattern, and the symmetry of this band corresponds to the crystal system. Since the band interval corresponds to the atomic plane interval, the function of measuring the crystal orientation and the crystal system by analyzing this pattern.
From the observation results of the sample described above with an electron microscope, it was confirmed that a large number of granular fine particles of magnetite were magnetically adsorbed on the entire surface of the shaft portion of the shaft member. As a result, it was confirmed that the magnetite fine particles were uniformly magnetically adsorbed on the surface of the shaft portion by heat-treating iron naphthenate in the air under the conditions described above. By sliding the shaft portion with the sliding surface, the bearing device has all the properties of the ten items described in the eighth paragraph.
Depending on the magnitude of the rotational force of the shaft member, the bearing member may be a conventional copper alloy such as brass or bronze, a tin-copper alloy called bavit metal, a tin antimony copper alloy, a lead antimony tin alloy, or Kelmet. A sliding surface may be formed by a member made of a copper lead alloy, a cadmium alloy, an aluminum alloy, or a synthetic resin shaft. The fit tolerance with the bearing member is based on the fit tolerance between the inner diameter of the slide surface and the outer diameter of the shaft portion because the inner diameter tolerance of the slide surface is H7 and the outer diameter tolerance of the shaft portion is f6 or e6. Process it. As a result, a gap of at least 25 microns is formed between the shaft portion and the sliding surface. On the other hand, since the size of magnetite magnetically adsorbed on the shaft portion is 40-60 nm, the magnetite fine particles are not peeled off from the shaft portion when the bearing member is assembled to the shaft member.

Example 2
Example 2 is an example according to the third embodiment in which iron naphthenate is used to uniformly adsorb the mitite fine particles to the mag on the surface of the shaft portion of the shaft member.
First, iron naphthenate as a raw material, n-butanol as a solvent, and a shaft member are prepared. As iron naphthenate, iron naphthenate commercially available as a metal soap (for example, a product of Toei Chemical Co., Ltd.) was used. For n-butanol, a reagent first grade was used. The shaft member is a kind of structural carbon steel and has carbon atoms of 0.25 Vol. % S25C.
Next, iron naphthenate is weighed so as to have a ratio of 8% by weight with respect to n-butanol, and this iron naphthenate is mixed with n-butanol and stirred to prepare an n-butanol dispersion of iron naphthenate. did. The container was filled with this dispersion, and the shaft members were immersed in the n-butanol dispersion of iron naphthenate so that the shaft portions of the shaft members were immersed. In addition, prepare a jig with a large number of holes in a disk-shaped plate, place a shaft member in the hole of this jig, and place this jig in a container containing n-butanol dispersion of iron naphthenate. By arrange | positioning, the axial part of a shaft member is immersed in the n-butanol dispersion of iron naphthenate.
Furthermore, the container was placed in a heat treatment furnace in an air atmosphere for heat treatment. First, the container was left in a low-temperature baking chamber at 120 ° C. for 5 minutes to vaporize n-butanol, and the vaporized n-butanol was recovered by a recovery machine. After n-butanol is vaporized, iron naphthenate is adsorbed on the surface of the shaft portion of all shaft members. Next, it heated up to 300 degreeC with the temperature increase rate of 10 degree-C / min, and also left to stand at 300 degreeC for 10 minutes, and thermally decomposed iron naphthenate into naphthenic acid and iron oxide FeO. Naphthenic acid produced by pyrolysis was vaporized, and the vaporized naphthenic acid was recovered by a recovery machine. Thereafter, the temperature was raised from 300 ° C. to 400 ° C. at a rate of 1 ° C./min, and further allowed to stand at 400 ° C. for 30 minutes to oxidize iron oxide FeO produced by pyrolysis to magmite. Finally, a collection of shaft members on which magnetite fine particles were magnetically adsorbed to the mag were taken out from the jig.
Next, a part of the shaft portion of the shaft member manufactured under the above conditions is taken out as a sample, and the sample is observed to check whether the target maghemite fine particles are reliably magnetically adsorbed on the surface of the shaft portion. Observed. The sample surface was observed with the electron microscope used in Example 1. A secondary electron beam between 900 and 1 kV of the reflected electron beam was taken out and subjected to image processing to observe irregularities on the sample surface. It was confirmed that an extremely large number of granular fine particles having a size of 40-60 nm were uniformly formed on the entire surface of the shaft portion in the sample. Next, the energy and intensity of characteristic X-rays were subjected to image processing, and the types of elements constituting the particulate particles adsorbed on the sample surface and their distribution states were analyzed. Both iron atoms and oxygen atoms were present uniformly on the surface, and no particularly uneven locations were found, so it was confirmed that they were granular fine particles made of iron oxide. Furthermore, an EBSP analysis function was added to the function of the extremely low acceleration voltage SEM, and the crystal structure was analyzed. From this result, it was confirmed that the particulate fine particles formed on the sample surface were maghemite.
From the observation result of the surface of the sample described above with an electron microscope, it was confirmed that the particulate fine particles of magnetite were evenly magnetically adsorbed on the surface of the shaft portion of the shaft member. From this result, it was confirmed that the iron naphthenate was heat-treated in the air under the conditions described above, and the magnetite fine particles were uniformly magnetically adsorbed on the surface of the shaft portion. By sliding the shaft portion with the sliding surface, the bearing device has all the properties of the ten items described in the eighth paragraph.
The bearing member may be formed with the sliding surface using the material described in the first embodiment in accordance with the magnitude of the rotational force of the shaft member. Further, the processing accuracy between the inner diameter of the sliding surface and the outer diameter of the shaft portion may be processed based on the fit tolerance described in the first embodiment. As a result, a gap of at least 25 microns is formed between the shaft portion and the sliding surface. On the other hand, since the size of the maghemite that is magnetically adsorbed to the shaft portion is 40-60 nm, when the bearing member is assembled to the shaft member, the maghemite fine particles are not peeled off from the shaft portion.

Example 3
Example 3 is an example in which acetylacetone iron is used as the organic iron compound in Embodiment 1 and magnetite fine particles are uniformly magnetically adsorbed on the surface of the shaft portion of the shaft member. Acetylacetone iron is an organic iron compound that is easily generated by the reaction of three molecules of acetylacetone with iron. Oxygen ions constituting acetylacetonate, which is a conjugate base of acetylacetone, bind to iron ions as a ligand. In addition, acetylacetonate is an inexpensive organic iron compound that forms a six-membered ring.
First, acetylacetone iron, n-butanol and a collection of shaft members as raw materials are prepared. As acetylacetone iron , acetylacetone iron commercially available as a metal soap (for example, Nersem ferric iron, a product of Nippon Chemical Industry Co., Ltd.) was used. For n-butanol, a reagent first grade was used. The shaft member was made of S25C, which is a kind of structural carbon steel.
Next, acetylacetone iron was weighed so as to have a ratio of 8% by weight with respect to n-butanol, and this acetylacetone iron was mixed with n-butanol and stirred to prepare an n-butanol dispersion of acetylacetone iron. The dispersion liquid was filled in a container, and the shaft member was immersed in the container with the collection of shaft members separated from each other. In addition, prepare a jig with many holes in a disk-shaped plate, place a shaft member in the hole of this jig, and place this jig in a container containing n-butanol dispersion of acetylacetone iron Thus, the shaft portion of the shaft member is immersed in the n-butanol dispersion of acetylacetone iron.
Furthermore, the container was placed in a heat treatment furnace in an air atmosphere for heat treatment. First, the container was allowed to stand at 120 ° C. for 5 minutes to vaporize n-butanol, and the vaporized n-butanol was recovered by a recovery machine. After n-butanol is vaporized, acetylacetone iron is adsorbed on the surface of the shaft portion of all shaft members. Then the temperature was raised to 330 ° C. from 120 ° C. to 10 ° C. / minute heating rate, and allowed to stand for 10 minutes to 330 ° C., pyrolyzed acetylacetone iron acetylacetonate and iron oxide FeO. The acetylacetone produced by the thermal decomposition was vaporized, and the vaporized acetylacetone was collected by a recovery machine. Thereafter, the temperature was raised to 350 ° C. at 1 ° C. / minute heating rate from 330 ° C., allowed to stand at 350 ° C. 30 minutes, and the iron oxide FeO produced in the pyrolysis is oxidized to magnetite. Finally, a collection of shaft members on which magnetite fine particles were magnetically adsorbed was taken out of the jig.
Next, the sample of the shaft portion of the shaft member manufactured under the above-mentioned conditions is observed in the same manner as the observation described in paragraph 26, and the magnetite particles having a size of 40-60 nm are formed on the surface of the shaft portion of the shaft member. The fact that the fine particles are evenly magnetically adsorbed was confirmed. From this result, it was confirmed that magnetite fine particles were uniformly magnetically adsorbed on the surface of the shaft portion by heat-treating acetylacetone iron in the air under the conditions described above. By sliding the shaft portion with the sliding surface, the bearing device has all the properties of the ten items described in the eighth paragraph.
In addition, what is necessary is just to form a sliding surface for the bearing member with the material demonstrated in Example 1 according to the magnitude | size of the rotational force of a shaft member. Further, the processing accuracy between the inner diameter of the sliding surface and the outer diameter of the shaft portion may be processed based on the fitting tolerance described in the first embodiment. As a result, a gap of at least 25 microns is formed between the shaft portion and the sliding surface. On the other hand, since the size of magnetite magnetically adsorbed on the shaft portion is 40-60 nm, the magnetite fine particles are not peeled off from the shaft portion when the bearing member is assembled to the shaft member.

Example 4
Example 4 is an example in which acetylacetone iron in Example 3 is used to uniformly adsorb magnetite fine particles onto the surface of the shaft portion of the shaft member.
First, acetylacetone iron, n-butanol and a collection of shaft members as raw materials are prepared. As acetylacetone iron , acetylacetone iron commercially available as a metal soap (for example, Nersem ferric iron, a product of Nippon Chemical Industry Co., Ltd.) was used. For n-butanol, a reagent first grade was used. The shaft member was composed of S25C, which is a kind of structural carbon steel.
Next, acetylacetone iron was weighed so as to have a ratio of 8% by weight with respect to n-butanol, and this acetylacetone iron was mixed with n-butanol and stirred to prepare an n-butanol dispersion of acetylacetone iron. The dispersion liquid was filled in a container, and the shaft member was immersed in the container with the collection of shaft members separated from each other. In addition, prepare a jig with many holes in a disk-shaped plate, place a shaft member in the hole of this jig, and place this jig in a container containing n-butanol dispersion of acetylacetone iron Thus, the shaft portion of the shaft member is immersed in the n-butanol dispersion of acetylacetone iron.
Furthermore, the container was placed in a heat treatment furnace in an air atmosphere for heat treatment. First, the container was allowed to stand at 120 ° C. for 5 minutes to vaporize n-butanol, and the vaporized n-butanol was recovered by a recovery machine. After n-butanol is vaporized, acetylacetone iron is adsorbed on the surface of the shaft portion of all shaft members. Then the temperature was raised to 330 ° C. from 120 ° C. to 10 ° C. / minute heating rate, and allowed to stand for 10 minutes to 330 ° C., pyrolyzed acetylacetone iron acetylacetonate and iron oxide FeO. The acetylacetone produced by the thermal decomposition was vaporized, and the vaporized acetylacetone was collected by a recovery machine. Thereafter, the temperature was raised to 1 ° C. / minute 430 ° C. at a heating rate of from 330 ° C., and allowed to stand for 30 minutes to 430 ° C., was oxidized in chromite to iron oxide FeO generated by pyrolysis to mug. Finally, a collection of shaft members on which magnetite fine particles were magnetically adsorbed to the mag were taken out from the jig.
Next, the same observation as described in paragraph 27 is performed on the sample of the shaft portion of the shaft member manufactured under the above-described conditions, and the maghemite granular having a size of 40-60 nm is formed on the shaft portion of the shaft member. The fact that the fine particles are evenly magnetically adsorbed was confirmed. From this result, it was confirmed that the magnesite fine particles were uniformly magnetically adsorbed on the surface of the shaft portion by heat-treating acetylacetone iron in the air under the conditions described above. By sliding the shaft portion with the sliding surface, the bearing device has all the properties of the ten items described in the eighth paragraph.
In addition, what is necessary is just to form a sliding surface for the bearing member with the material demonstrated in Example 1 according to the magnitude | size of the rotational force of a shaft member. Further, the processing accuracy between the inner diameter of the sliding surface and the outer diameter of the shaft portion may be processed based on the fitting tolerance described in the first embodiment. As a result, a gap of at least 25 microns is formed between the shaft portion and the sliding surface. On the other hand, since the size of the maghemite that is magnetically adsorbed to the shaft portion is 40-60 nm, when the bearing member is assembled to the shaft member, the maghemite fine particles are not peeled off from the shaft portion.

Claims (3)

A shaft member which rotates, the shaft portion of the shaft member is have you the bearing device comprising a sliding bearing member having a slidable sliding surface, the shaft member, magnetite or maghemite in the surface of the shaft portion having a magnetic a shaft member granular particles are evenly magnetic attraction comprised of any material, a method of manufacturing a shaft member, an organic iron compound to produce the iron oxide FeO by thermal decomposition, which is dispersed in an organic solvent dispersion Creating a liquid, immersing the shaft portion of each shaft member in the collection of shaft members in the dispersion of the organic iron compound, bringing the dispersion of the organic iron compound into contact with the surface of the shaft portion; The dispersion liquid is heated to vaporize the organic solvent, the organic iron compound is adsorbed on the shaft portion of the shaft member, and the assembly of the shaft members is heat-treated in the atmosphere to heat the organic iron compound. Iron oxide Fe by decomposition Is deposited on the surface of the shaft portion, and further heated to oxidize the iron oxide FeO to magnetite or maghemite, thereby, on the surface of the shaft portion of each shaft member in the group of shaft members, A method of manufacturing a shaft member, characterized in that a group of shaft members in which granular fine particles made of any one of magnetite and maghemite are magnetically adsorbed are manufactured . The organic iron compound that generates iron oxide FeO by thermal decomposition according to claim 1 is an organic iron compound in which iron ions coordinate with oxygen ions, and the organic iron compound is converted into iron oxide by thermal decomposition in claim 1. used as the organic iron compound that produces FeO, characterized in that to produce a collection of the shaft member in accordance with the method of claim 1, method for producing a shaft member according to claim 1. The organic iron compound in which the iron ion according to claim 2 is coordinated to an oxygen ion is an iron carboxylate compound or iron acetylacetone iron selected from iron acetate, iron benzoate, iron caprylate, and iron naphthenate. an iron compound, using the organic iron compound as the organic iron compound in claim 2, characterized in that to produce a collection of the shaft member in accordance with the method of claim 2, and claim 2 Manufacturing method of shaft member .

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