WO2005101985A2 - 動圧発生部の成形方法および動圧軸受装置 - Google Patents
動圧発生部の成形方法および動圧軸受装置 Download PDFInfo
- Publication number
- WO2005101985A2 WO2005101985A2 PCT/JP2005/007092 JP2005007092W WO2005101985A2 WO 2005101985 A2 WO2005101985 A2 WO 2005101985A2 JP 2005007092 W JP2005007092 W JP 2005007092W WO 2005101985 A2 WO2005101985 A2 WO 2005101985A2
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- WO
- WIPO (PCT)
- Prior art keywords
- dynamic pressure
- ink
- bearing
- pressure generating
- shaft member
- Prior art date
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K5/00—Casings; Enclosures; Supports
- H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
- H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
- H02K5/167—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings
- H02K5/1675—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using sliding-contact or spherical cap bearings radially supporting the rotary shaft at only one end of the rotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/02—Sliding-contact bearings for exclusively rotary movement for radial load only
- F16C17/026—Sliding-contact bearings for exclusively rotary movement for radial load only with helical grooves in the bearing surface to generate hydrodynamic pressure, e.g. herringbone grooves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C17/00—Sliding-contact bearings for exclusively rotary movement
- F16C17/10—Sliding-contact bearings for exclusively rotary movement for both radial and axial load
- F16C17/102—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure
- F16C17/107—Sliding-contact bearings for exclusively rotary movement for both radial and axial load with grooves in the bearing surface to generate hydrodynamic pressure with at least one surface for radial load and at least one surface for axial load
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/06—Sliding surface mainly made of metal
- F16C33/10—Construction relative to lubrication
- F16C33/1025—Construction relative to lubrication with liquid, e.g. oil, as lubricant
- F16C33/106—Details of distribution or circulation inside the bearings, e.g. details of the bearing surfaces to affect flow or pressure of the liquid
- F16C33/107—Grooves for generating pressure
Definitions
- the present invention relates to a method for forming a dynamic pressure generating portion on a material, and a dynamic pressure bearing device having the dynamic pressure generating portion.
- a dynamic pressure bearing is a bearing that generates pressure by a dynamic pressure action of a fluid generated in a bearing gap due to relative rotation of a shaft member and a bearing sleeve, and uses the pressure to support the shaft member in a non-contact manner.
- This dynamic bearing has features such as high-speed rotation, high rotation accuracy, and low noise.
- dynamic pressure grooves for generating dynamic pressure are formed in the outer peripheral surface of the shaft member in a herringbone shape, a spiral shape, or the like as a dynamic pressure generating portion.
- the following methods (1) to (3) are known as methods for accurately forming this special and complicated dynamic pressure groove shape.
- a portion other than the dynamic pressure groove is printed on the outer periphery of the shaft member with a corrosion-resistant ink by a combination of electrochemical methods, and the non-printed portion is etched to corrode to form the dynamic pressure groove.
- Patent Document 1 JP-A-57-35682
- the printing die since the printing die contacts and moves with the outer peripheral surface of the shaft member, abrasion occurs at the contact portion, and immediately after mass production, the printing accuracy deteriorates due to wear or deformation of the printing die. Is concerned.
- the ink supply unit supplies the corrosion-resistant ink to the outer peripheral surface of the shaft member via the printing die, and is further pressed by a squeegee to be fixed on the outer peripheral surface of the shaft member. Therefore, the use of expensive anti-corrosion ink increases, which is uneconomical.
- the ink when the ink is cured by ultraviolet irradiation as described above, the ink first starts to cure from a portion irradiated with ultraviolet rays, that is, the outside of the ink, and the curing of the bonding interface is delayed more than this. . Therefore, the bonding state at the interface between the ink and the shaft member becomes unstable until the curing action by the ultraviolet ray occurs near the interface. Therefore, depending on the printing conditions, the specifications of the bearing device, etc., ink may drop or peel during printing or in a subsequent process. Dropping or peeling of ink impairs the accuracy of the dynamic pressure generating part, causing the dynamic pressure bearing device to rotate. This leads to a decrease in accuracy.
- An object of the present invention is to enable a dynamic pressure generating portion to be formed with high accuracy and low cost in a simple process in view of a powerful situation.
- the present invention provides a method of supplying a small amount of ink to the surface of a material, and printing a dynamic pressure generating unit for generating a fluid dynamic pressure in a bearing gap with an aggregate of the small amount of ink. And a step of curing the ink.
- the “dynamic pressure generating portion” here is not particularly limited in its form as long as it can generate pressure in the bearing gap by the dynamic pressure action of a fluid.
- a plurality of grooves axial grooves, Or an inclined groove such as a spiral or a ring bone
- a convex back portion between the grooves and defining the groove or wedge the bearing gap in one or both directions in the circumferential direction.
- the like having a plurality of arc-shaped surfaces to be reduced into a shape.
- the “dynamic pressure generating section” can be formed on, for example, an outer peripheral surface or an end surface of a shaft member, or an inner peripheral surface or an end surface of a sleeve-like member (such as a bearing sleeve), and the printing surface has a curved surface. It does not matter whether it is flat or flat.
- the material for forming the dynamic pressure generating portion is not particularly limited, and a metal material (a steel material such as stainless steel, a soft metal such as machinyu, a sintered metal, etc.), and a resin composition are required. It is appropriately selected and used depending on the bearing characteristics to be used.
- a so-called inkjet method As a specific method of supplying a small amount of ink to the surface of the material when forming the dynamic pressure generating portion, for example, a minute droplet of ink is ejected from a nozzle to land on the surface of the material, a so-called inkjet method. Can be mentioned.
- the ink surface force that does not pass through the nozzles is also reduced by a nozzleless ink jet method that ejects ink droplets, a method that induces ink using electrophoresis, or a method that uses a micropipette to transfer ink continuously instead of in the form of droplets.
- a method of discharging the ink or a method of shortening the distance to the fixing surface and causing the ink to land on the fixing surface simultaneously with the discharge can also be used.
- the supply amount and the supply position of the trace ink can be precisely controlled, so the shape pattern of the dynamic pressure generating section is programmed in advance, and the position of the ink supply section (for example, nozzle), the ink supply amount, and the ink supply '
- the shape pattern of the dynamic pressure generating section is programmed in advance, and the position of the ink supply section (for example, nozzle), the ink supply amount, and the ink supply '
- the shape it is possible to print an arbitrary and high-precision shape pattern with an aggregate of fine droplets of ink, and to form each part of the shape pattern with an arbitrary thickness.
- ink supply method exemplified above, printing can be performed without contact between the ink supply unit and the material surface, so that high-precision printing can be performed. It is possible to avoid a decrease in accuracy due to wear at the contact portion, which is a problem.
- ink is used only where it is not necessary to remove excess ink with a squeegee after supplying excess ink to the printing mold, the ink is only involved in forming the dynamic pressure generating part. The used amount is sufficient, and the used amount of ink can be reduced.
- the molding apparatus can be simplified.
- the dynamic pressure generating portion can be formed by the cured ink (resin composition) itself.
- the dynamic pressure generating part made of ink can be used as a bearing surface by directly incorporating it into the dynamic pressure bearing device without going through the corrosion process by etching, etc., and the process of removing the corrosion-resistant ink after etching. It becomes possible. This greatly simplifies the process of forming the dynamic pressure generating portion.
- a printing section for printing the dynamic pressure generating section and a curing section for curing the ink are provided at different circumferential positions, and the material and the printing section and the curing section are rotated relative to each other to obtain the dynamic pressure. If the printing of the generating section and the curing of the ink proceed in the circumferential direction of the material, the printing of the dynamic pressure generating section on the surface of the material and the curing of the ink can proceed simultaneously, reducing the cycle time. I can do it. In addition, when the printing start portion on the surface of the material rotates once, the ink is completely cured, so that it is possible to avoid a decrease in printing accuracy due to overlapping of insufficiently cured ink.
- the material exerts a shielding function against the curing action of the ink in the curing section (for example, irradiation of ultraviolet rays when using an ultraviolet curing type ink), the curing action reaches the printing section and the printing operation is performed. Can be avoided. From this perspective, It is desirable that the printing section and the hardened section are arranged at positions facing each other across the axis of the material.
- the ink that can be cured by irradiation of electromagnetic waves such as electron beams and light rays
- use a photo-curable ink and cure the ink by irradiation of light Is desirable.
- the photo-curable ink UV-curable and infrared-curable inks, as well as visible light-curable inks, can be used. UV-curable inks that can be cured at low cost and in a short time are particularly desirable. .
- the above-described dynamic pressure generating unit includes an ink supply unit that intermittently supplies a small amount of ink to the surface of the material, and a light source that irradiates a light beam for curing the ink.
- the source and the material can be molded by a molding device that is arranged opposite to the material and at a different circumferential position, and that relatively rotates the material and the ink supply unit and the light source.
- a shaft member having a dynamic pressure generating portion on the outer peripheral surface can be manufactured at low cost.
- the hydrodynamic bearing device can be constituted by this shaft member and a bearing sleeve having the shaft member inserted in the inner periphery.
- the inner peripheral surface of the bearing sleeve can be a smooth cylindrical surface having no dynamic pressure generating portion.
- a bearing sleeve having a dynamic pressure generating portion on the inner peripheral surface can be manufactured.
- the dynamic pressure bearing device can be constituted by this bearing sleeve and a shaft member inserted into the inner periphery of the bearing sleeve.
- the outer peripheral surface of the shaft member can be a smooth cylindrical surface having no dynamic pressure generating portion.
- a shaft member having a dynamic pressure generating portion formed on the outer peripheral surface formed by the above-described forming method and the forming device, and a dynamic pressure generating portion formed on the inner circumferential surface by the same forming method and the forming device are provided.
- the dynamic pressure bearing device can also be configured with the bearing sleeve.
- the ink forming the dynamic pressure generating portion is completely removed after the etching, so that no ink component remains on the material surface.
- the dynamic pressure generating portion is formed by ink as in the present invention, the ink as the resin composition remains on the surface of the shaft member and the bearing sleeve without being removed.
- the contact between the shaft member and the bearing sleeve at the time of starting and stopping the bearing is performed through the resin composition, and therefore, the material of the member having the dynamic pressure generating portion (the shaft member or the bearing sleeve) is made of the mating member. Non-contact with the member. Therefore, the required property of the material is abrasion resistance.
- the dynamic pressure bearing device includes a housing, a bearing sleeve fixed to the inner periphery of the housing, a shaft member inserted into the inner periphery of the bearing sleeve, and a shaft member that is radially non-conductive.
- a radial bearing part that supports the contact, a thrust bearing part that supports the shaft member in the thrust direction, and an aggregate of a small amount of ink supplied to the surface of the material of the shaft member is cured to generate fluid dynamic pressure in the bearing gap And a dynamic pressure generating section.
- the radial bearing portion is formed of a dynamic pressure bearing.
- the shaft member is supported in a radially non-contact manner by the dynamic pressure action of the lubricating fluid generated in the radial bearing gap between the outer peripheral surface and the inner peripheral surface of the bearing sleeve.
- the thrust bearing portion is formed of a dynamic pressure bearing.
- the shaft member is supported in a non-contact manner in the thrust direction by the dynamic pressure action of the lubricating fluid generated in the thrust bearing gap.
- the above-described dynamic pressure generating portion which is a collective force of a small amount of ink, may be provided on both the radial bearing and the thrust bearing, or may be provided on only one of the bearings.
- the dynamic pressure generating portion is formed of the resin composition formed by curing the ink as described above, the compatibility between the resin composition forming the dynamic pressure generating portion and the oil (words In other words, the oil resistance of the resin composition) becomes a problem.
- the dynamic pressure generating portion is made of, for example, a metal, the metal has oil resistance to oil, so there is no particular problem in use.However, the dynamic pressure generating portion is formed of a resin composition. In such cases, it is necessary to select the type of resin composition in consideration of the oil resistance to the oil used.
- the oil filled in the bearing device penetrates from the surface of the resin composition into the inside, and swells the resin composition.
- the dynamic pressure generating portion formed of the resin composition swells, the elastic modulus of the dynamic pressure generating portion is reduced, and this lowering of the elastic modulus may further cause problems such as abrasion.
- lubricating oil may penetrate inside the resin composition As a result, the interfacial adhesion between the resin composition and the material (for example, the shaft member and the bearing sleeve) is weakened, and the resin composition may be peeled off from the material.
- the shaft member, the bearing gap facing the shaft member, the oil filled in the bearing gap, and the dynamic pressure generating portion for generating a dynamic pressure action of the oil in the bearing gap are provided.
- the dynamic pressure generating part is formed of a resin composition, and the solubility parameter of the base resin and the oil solubility parameter of the base resin contained in the resin composition is 1.0 or more in absolute value. I was able to make a difference.
- solubility parameter is an index indicating the electrical polarity of the material, and the closer the solubility parameter values are to each other, the easier it is for the materials having different solubility parameter values to be easily dissolved. The more it is, the more difficult it is to melt with each other.
- solubility parameter Solubility Parameter; hereinafter also referred to as SP value: ⁇ was calculated based on the following R. F. Fedors calculation formula.
- the unit related to the SP value will be (cal / cm 3 ) 1/2 according to the customary use.
- the dynamic pressure generating part is formed of a resin composition comprising a base resin having an SP value having a difference of 1.0 or more in absolute value with respect to the solubility parameter of the oil
- the surface force of the dynamic pressure generating portion formed of this resin composition can prevent oil from entering the inside. Accordingly, it is possible to avoid a decrease in the elastic modulus due to the swelling of the dynamic pressure generating portion, and to prevent wear due to contact with a member facing the dynamic pressure generating portion. Alternatively, it is possible to prevent the resin-made dynamic pressure generating portion from peeling off the material to be fixed (shaft member / bearing member, etc.).
- the absolute value difference 1.0 of the solubility parameter between the two is based on the resin composition (particularly the base resin). And a boundary value for determining whether the oil and the oil are compatible or insoluble. That is, as the absolute value difference becomes smaller than 1.0, the amount of swelling of the resin composition by oil increases, but when the absolute value difference becomes 1.0 or more, it depends on the value. Instead, the swelling of the resin composition by oil becomes very small, so that adverse effects on bearing performance can be avoided.
- the resin composition of the dynamic pressure generating section can be formed by curing an aggregate of a small amount of ink by using an ink-jet method or the like in the same manner as described above.
- a resin that can be cured by various kinds of cask with energy can be used as the base resin of the resin composition.
- a photocurable resin is used, and It is preferred that the resin be cured by irradiation.
- a visible light curable resin can be used in addition to an ultraviolet curable resin and an infrared curable resin, but an ultraviolet curable resin which can be cured at a low cost in a short time is particularly preferable.
- diester lubricating oils can be particularly preferably used.
- the resin composition according to the present invention is a resin composition that forms a dynamic pressure generating portion for generating a dynamic pressure action of oil in a bearing gap on the surface of a raw material.
- the solution parameter is characterized by having an absolute value of at least 1.0 with respect to the solubility parameter of the oil in contact with the surface of the dynamic pressure generating section.
- the oil according to the present invention is formed on the surface of the raw material and comes into contact with the surface of the dynamic pressure generating portion that generates the dynamic pressure action of the oil in the bearing gap, and the solubility parameter is determined by the dynamic pressure. It has a difference of at least 1.0 in absolute value with respect to the solubility parameter of the base resin of the resin composition forming the generating part.
- the dynamic pressure bearing device includes a shaft member, a bearing gap facing the shaft member, and a dynamic pressure generating unit for causing a dynamic pressure action of fluid in the bearing gap. It is also possible to use those formed by curing an aggregate of a small amount of ink and using a thermosetting ink. This means that the ink is thermally cured when forming a dynamic pressure generating section for generating a dynamic pressure action of the fluid in the bearing gap with an aggregate of a small amount of ink on the material surface.
- the ink can be cured by directly irradiating heat, or can be cured by heating a material and utilizing heat conduction.
- the latter method (the material is heated and cured by heat conduction) is more desirable in order to promote the curing from the bonding interface and ensure good adhesion at an early stage.
- the manufacturing process can be simplified.
- the material can be pre-heated before being put into the printing process.
- the curing of the ink can be started at the same time as the printing, and the dynamic pressure generating portion having high accuracy and high durability can be formed by preventing the ink from peeling or falling off. It becomes.
- the method of heating the material may be so-called internal heating or external heating.
- thermosetting properties in addition to those having only thermosetting properties, those having both thermosetting properties and photocuring properties can be used.
- the curing action of both heat and light promotes the curing of both the ink surface and the adhesive interface.Thus, the curing speed can be significantly increased, and the total time can be reduced to reduce manufacturing costs. be able to. In this case, a separate light irradiation device needs to be provided for photocuring.
- thermosetting resin is used as a base resin, and a thermosetting initiator and a photocuring (polymerization) initiator are mixed with the base resin. Or a heat and light curing (polymerization) initiator.
- a photo-curing initiator an ultraviolet-curing type, an infrared-curing type, and a visible-light-curing type can be used.
- An ultraviolet-curing type which can be cured in a low cost and in a short time, is particularly preferable.
- the motor having the dynamic pressure bearing device having the above configuration, the rotor magnet, and the stator coil is used for a magnetic disk such as a node disk drive (HDD) for the above information equipment. It can be preferably used as a spindle motor or the like for a disk drive device.
- HDD node disk drive
- the step of etching the dynamic pressure generating section and the step of removing the cured ink can be omitted, and the dynamic pressure generating section can be formed at low cost.
- the dynamic pressure bearing device having a high-precision dynamic pressure generating section can be obtained at low cost.
- the dynamic pressure generating portion is formed of a resin composition having excellent oil resistance, abrasion of the surface of the dynamic pressure generating portion can be suppressed. Therefore, stable bearing performance can be secured over a long period of time, and the durability of the hydrodynamic bearing device can be improved.
- the cycle time for forming the dynamic pressure generating portion can be reduced to reduce cost, and a highly accurate dynamic pressure generating portion can be formed. It can be formed.
- FIG. 1 shows an outline of an ink-jet type molding apparatus as an example of a molding apparatus for a dynamic pressure generating section that works on the present invention.
- the raw material 2a 'of the shaft member 2 is supported by the shaft-shaped holding portion 13 against which both-side forces are pressed in the horizontal posture.
- the two holding portions 13 are rotatably supported by rolling bearings 15, and one of the holding portions 13 is connected to a rotation drive portion 19 that also has a motor or the like.
- the rotation drive unit 19 By activating the rotation drive unit 19, the material 2a 'that has received the rotational power via the holding unit 13 rotates.
- the raw material 2a ' has a shaft shape that also has the strength of a metal material such as stainless steel.
- One or a plurality of nozzle heads 11 and light sources 21 are arranged on the outer periphery of the material 2a '.
- the nozzle head 11 is a printing unit that supplies ink to the outer periphery of the material 2a ′
- the light source 21 is a curing unit that cures the supplied ink.
- the nozzle head 11 and the light source 21 are arranged at different positions in the circumferential direction, and are preferably arranged at opposing positions across the material 2a 'as shown in the figure.
- the nozzle head 11 is provided with a plurality of nozzles 14 for ejecting fine droplets of the ink 12 in the axial direction.
- the ink 12 stored in the ink tank 18 is supplied to the nozzle head 11 via the ink supply pipe 17 and further supplied to the nozzle driven by the nozzle head driving unit 15.
- the liquid droplets are intermittently discharged from each nozzle 14 of the head 11 as fine droplets.
- the nozzle head drive unit 15 adopts a configuration corresponding to each type of discharge Is done.
- the printing method of the nozzle head 11 may be either a continuous (continuous) type or an on-demand type.
- the ink 14 is, for example, a resin composition containing a photocurable resin as a base resin, and may be used in which an organic solvent is blended in an appropriate ratio as needed.
- a resin composition (ultraviolet-curable ink) based on an ultraviolet-curable resin that causes a polymerization reaction and is fixed by irradiation with ultraviolet rays is used.
- an ultraviolet irradiation lamp is used as the light source 21.
- Examples of the ultraviolet-curable resin constituting the base resin of the ultraviolet-curable ink include, for example, radical polymerizable monomers, radical polymerizable oligomers, and cationic polymerizable monomers, as well as imidatalylate and cyclic polyene conjugates. And thiol compounds represented by polythiol conjugates. Among them, radically polymerizable monomers, radically polymerizable oligomers, and cationically polymerizable monomers can be preferably used.
- Radical polymerization--As the monomer for example, monofunctional, bifunctional, or polyfunctional atalylate monomer or metharylate monomer can be used, and as the radical polymerizable monomer, for example, urethane acrylate, epoxy acrylate, polyester Atarilate or unsaturated polyester can be used.
- Examples of cationic polymerization monomers include, for example, bisphenol A epoxy resin, phenol novolak epoxy resin, alicyclic epoxy resin, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis ⁇ [(3-Ethyl 3-oxetal) methoxy] methyl ⁇ benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [1-ethyl (3-oxetal)] methyl ether, 3-ethyl-3- (2-ethyl) Oxetane resins such as hexyloxymethyl) oxetane and 3-ethyl-3- ⁇ [3 (triethoxysilyl) propoxy] methyl ⁇ oxetane can be used. These UV-cured resins are used alone or in combination of two or more as a base resin.
- These base resins have a radical system for causing a polymerization reaction by ultraviolet irradiation.
- a photopolymerization initiator such as a photopolymerization initiator and a cationic photopolymerization initiator is added.
- Radical photopolymerization initiators include, for example, benzophenone, methyl orthobenzoin benzoate, 4-benzoyl-4'-methyldiphenyl sulfide, ammonium salts of benzophenone, isopropylthioxanthone, getylthioxanthone and thioxanthone.
- a hydrogen abstraction type photopolymerization initiator represented by an ammonium salt can be used, or a benzoin derivative, benzyldimethyl ketal, ⁇ -hydroxyalkylphenone, ⁇ -aminoalkylphenone, acylphosphine oxide,
- An intramolecular cleavage type photopolymerization initiator typified by acryloxyphosphine oxide, bisacylphosphine oxide, acrylphenylglyoxylate, diethoxyacetophenone, and titanocene conjugate can be used.
- the cationic photopolymerization initiator include, for example, triphenylsulfo-dimethylhexafluoroantimonate, triphenylsulfo-dimethylhexafluorophosphate, S
- P-170-SP-150 both manufactured by Asahi Denka Co., Ltd.
- FC-508-FC-512 both manufactured by 3M Company
- UVE-1014 General Electric Company
- These photopolymerization initiators can be used alone or in combination of two or more.
- the formation of the dynamic pressure generating portion A is performed in such a manner that it gradually progresses in the circumferential direction of the outer peripheral surface of the material 2a 'as the material 2a' rotates.
- the printed portion progresses to some extent in the circumferential direction (halfway in the illustrated example) and the printed portion reaches the area facing the light source 21, the ultraviolet light Is irradiated, the ink 12 undergoes a polymerization reaction and is cured.
- the curing of the ink also progresses gradually in the circumferential direction of the material 2a 'with the rotation of the material 2a'.
- the material 2a ' is rotated one to several tens of times while sliding the nozzle head 11 in the axial direction and discharging and discharging the ink 12 from each nozzle 14 as appropriate, thereby stopping the entire surface of the material 2a'.
- a dynamic pressure generating section A is formed around the circumference. When the printing of the dynamic pressure generating section A is completed and all the ink 12 has hardened, the rotation drive section 19 is stopped, and the material 2a 'is removed from the holding section 13.
- the nozzle head 11 can be arranged at a fixed position in addition to sliding the nozzle head 11 in the axial direction. Further, in the illustrated example, a case where one nozzle head 11 is used is illustrated, but this may be arranged at a plurality of positions in the axial direction or the circumferential direction. Further, as shown in FIG. 3, a plurality of materials 2a 'are connected in series, and one or a plurality of nozzle heads 11 are slid in the axial direction while simultaneously rotating these materials, so that each material 2a' is subjected to a dynamic pressure generation section A. Can also be printed. In this case, the coaxiality of the raw materials 2a 'can be ensured by, for example, fitting the convex portion 2a2 provided on one shaft end to the concave portion provided on the other.
- the minute droplets 12 of the ink can be precisely ejected according to the shape pattern programmed in advance, and the ink film thickness after printing is accurately controlled. can do. Therefore, it is possible to form the high-precision dynamic pressure generating section A with the cured ink 12 and to secure a necessary dynamic pressure groove depth (several ⁇ m to several tens ⁇ m).
- the pressure generating section A can be used as it is as the bearing surface of the dynamic pressure bearing.
- the conventional method does not require an etching step or a hardened ink removing operation, so that the step of forming the dynamic pressure generating portion A is simplified, and the intensive processing cost can be reduced. Further, corrosion resistance is not required as a characteristic of the ink, and the degree of freedom in selecting the ink to be used can be increased.
- the ink 12 on the outer peripheral surface of the shaft member 2 comes into sliding contact with the mating member (for example, the bearing sleeve 8 shown in FIG. 2).
- the wear resistance becomes less important. Therefore, in addition to being able to increase the degree of freedom in selecting a material for the shaft member 2, heat treatment for improving wear resistance is not required, so that the shaft member can be formed from an unheated metal material. Powerful material costs can be reduced.
- the portions can be made continuous with a uniform film thickness.
- the printing area is hardened in a short time by using a photocurable resin as the ink 12 and using an ultraviolet lamp as the light source 21, so that the printed dynamic pressure generating section is used. A can be maintained with high precision without losing its shape.
- useless use of the ink 12 can be avoided, and material cost can be reduced.
- the first printed portion is cured by the irradiation of the ultraviolet light from the light source 21 and then returns to the position facing the nozzle head 11. It is also possible to avoid a situation where the generator A is broken. Further, since the nozzle head 11 and the light source 21 are arranged at positions facing each other across the material 2a ', ultraviolet rays from the light source 21 are blocked by the material 2a' and do not reach the area facing the nozzle head 11. Therefore, it is possible to prevent the nozzle 14 from being clogged by the hardened ink while the hardening operation of the ultraviolet light reaches the nozzle head 11 and to perform the printing operation efficiently.
- the shaft member 2 with the dynamic pressure grooves is manufactured by performing etching as needed, forming the dynamic pressure grooves Ab by the corrosive action, and removing the ink. Talk about things.
- FIG. 4a a force exemplifying a case where a dynamic pressure groove Ab is formed at a portion covered with ink.
- a portion (ink layer) 22 covered with ink is used.
- the dynamic pressure groove Ab can also be formed.
- the entire outer peripheral surface of the material 2a ' is covered with the S ink layer 22, and a convex back Aa is further formed thereon, so that the adhesion area of the ink to the material 2a' is increased, It is possible to suppress a decrease in the durable life due to peeling off or the like.
- the material 2a ′ for rotating the material 2a ′ is fixed, and the nozzle 2a ′ is fixed.
- the printing and curing of the dynamic pressure generating portion A may be performed by rotating the head 11 and the light source 21 around the material 2a '.
- FIG. 2a and FIG. 2b are cross-sectional views showing a schematic configuration of a hydrodynamic bearing device using the shaft member 2 made of the material 2a ′ manufactured in the above process.
- Each of the bearing devices shown in FIGS. 9A and 9B has a dynamic pressure generating portion A formed on the outer peripheral surface of the shaft member 2 by the above-described molding device.
- a radial bearing gap is formed between the bearing sleeve 8 and the inner peripheral surface of the bearing sleeve 8 which faces the bearing.
- the bearing sleeve 8 is formed in a cylindrical shape from a soft metal or a sintered metal impregnated with oil, and the shaft member 2 is inserted into the inner periphery thereof.
- the dynamic pressure groove Ab generates a dynamic pressure action of the lubricating fluid (oil, air, magnetic fluid, etc.) filled in the radial bearing gap.
- Radial bearings Rl and R2 are configured to support the shaft member 2 in a radially non-contact manner by the pressure generated in the radial bearing gap by the dynamic pressure action.
- a thrust bearing portion T is formed in which one end of the shaft member 2 is brought into contact with the thrust plate Sp to support the shaft member 2 in the thrust direction.
- the bearing device shown in Fig. 1 (b) is one in which the thrust bearing portions Tl, # 2 are constituted by hydrodynamic bearings, and the shaft member 2 is composed of a shaft portion 2a and an integral or separate body with the shaft portion 2a. It consists of a flange 2b. Both ends 2bl and 2b2 of the flange portion 2b generate a fluid dynamic pressure action in the thrust bearing gap between the end face of the bearing sleeve 8 and the end face of the thrust plate Sp, and the pressure generated by the dynamic pressure action causes the shaft member to move. 2 is supported non-contact in both directions of thrust.
- one of the two end faces 2bl, 2b2 of the flange portion 2b is formed by existing means such as a press, and the dynamic pressure generating portion A of the radial bearing portions Rl, R2 is used.
- it can be formed by printing by an ink jet method and curing.
- FIG. 5 shows an example of a molding apparatus that forms a dynamic pressure generating portion on the upper end face 2b1 of the two end faces 2bl and 2b2 of the flange portion 2b (dynamic pressure generation on the lower end face 2b2).
- the configuration of the forming device that forms the portion is the same as the device that is formed on the upper end face 2bl, and thus the description is omitted.
- the main components of this molding apparatus are the same as those of the molding apparatus shown in FIG. 1 except that the nozzle head 11 and the light source 21 are arranged so as to face the upper end surface 2b1 of the material 2b 'to be rotationally driven.
- the nozzle head 11 and the light source 21 on the upper end face 2b 1 This is the point where they are arranged with different directions.
- the nozzle head 11 is reciprocated in the radial direction while rotating the material 2b 'held by the holding unit 13, and the ink 12 is ejected from the nozzle 14 of the nozzle head 11, so that the minute droplets of the ink 12 are discharged. Lands at a predetermined position on the upper end surface 2bl of 2b '.
- the aggregate of the microdroplets forms a dynamic pressure generating portion having, for example, a dynamic pressure groove arranged in a spiral shape on the upper end face 2bl of the material 2b '.
- the printing of the dynamic pressure generating part is performed in such a manner that the printing part gradually advances in the circumferential direction with the rotation of the material 2b ', and when the printing part reaches the area facing the light source 21, the ink 12 irradiated with the ultraviolet rays is polymerized. It reacts and cures sequentially.
- the shaft member is rotated one to several tens of rotations while appropriately switching the supply and stop of the ink 12 from each nozzle 14 to form a dynamic pressure generating portion over the entire circumference of the upper end surface 2bl of the material 2b '.
- the dynamic pressure generating portion A is formed on the outer peripheral surface of the shaft member 2 as the radial bearing portions Rl and R2 has been described, but the inner peripheral surface of the bearing sleeve 8 is formed in a similar manner.
- the dynamic pressure generating section A can be formed in the same.
- the nozzle head 11 and the light source 21 are arranged so as to face the inner peripheral surface of the material (sleeve-shaped material) of the bearing sleeve 8 and have different circumferential positions.
- oil such as lubricating oil is often used as a lubricating fluid for the dynamic pressure bearing device.
- the dynamic pressure generating portion A is formed of the cured ink (resin composition) as described above, the resin composition constituting the dynamic pressure generating portion A is constantly immersed in oil. Therefore, if the oil resistance of the resin composition is insufficient, swelling of the resin composition causes a decrease in the elastic modulus of the dynamic pressure generating portion and the like, which adversely affects bearing performance.
- the oil resistance of the base resin can be evaluated by the difference between its solubility parameter and the solubility parameter (SP value) of the lubricating oil that comes into contact with the surface of the dynamic pressure generating section A, and is verified by the present inventors. For example, it was found that if the difference was at least 1.0 in absolute value, the required oil resistance could be obtained.
- SP value solubility parameter
- a synthetic lubricating oil is mainly used.
- synthetic lubricating oils include synthetic hydrocarbons, polyalkylene glycols, diesters, polyol esters, phosphoric esters, silanes, silicates, silicones, and polyether ethers. And fluorocarbon-based lubricants.
- diester-based lubricating oils exhibiting a relatively low evaporation rate and low viscosity are preferable in consideration of the working environment of the dynamic pressure bearing.
- diester lubricating oil for example, dioctyl adipate ⁇ , dioctyl azelate, dioctyl sebacate, diisooctyl adipate, disodecyl adipate and the like can be used.
- the oil exemplified here and the base resin (ultraviolet curable resin) exemplified above may be appropriately used as long as the absolute value difference of the solubility parameter (SP value) between the two is 1.0 or more. It can be used in combination.
- the present inventors have proposed a combination of a resin composition and an oil in which the absolute value difference of the solubility parameter is less than 1.0, and a resin composition in which the absolute value difference of the solubility parameter is 1.0 or more.
- a friction test was performed on each of the combination of the object and the oil, and a comparative experiment of oil resistance was performed. The details of the comparative experiment are as follows.
- the UV-curable resin serving as the base resin of the resin composition 12 includes a cationic polymerizable monomer, 3-ethyl-2- (2-ethylhexyloxymethyl) oxetane, as Aronoxetane OXT—produced by Toagosei Co., Ltd. 212 (SP value: 8.1) was used. Further, as the cationic polymerization monomer, 3-alone-3hydroxymethyloxetane, aronoxetane OXT-101 (SP value: 10.9), also manufactured by Toagosei Co., Ltd. was used.
- Uvacure 1590 manufactured by Daicel U.S.C.B.
- Tvacure 1590 was used as a mixture of triaryl sulfohexafluoride phosphate salt, which is a cationic polymerization initiator, and each base resin was mixed.
- a resin composition was prepared by adding 3 parts each to 100 parts (the former was No. 1 and the latter was No. 2).
- reagent code No. 047-24191 (SP value: 8.8) manufactured by Wako Pure Chemical Industries, Ltd. was used as dioctyl adipate (DOA), which is a diester lubricating oil.
- the sample fixed on the sample was used as a test sample.
- the solubility parameter for the test oil A resin composition No. 1 (absolute value difference of SP value: 0.7) consisting of a base resin with an absolute value difference of less than 1.0 was fixed on the substrate, Specimen with base resin having absolute value difference of solubility parameter to oil of 1.0 or more and resin composition No. 2 (absolute value difference of SP value: 2.1) fixed on the above substrate Body.
- the above-mentioned embodiment and comparative body were each immersed in the above-mentioned test oil (DOA) under the condition of 100 ° C X 100HOur. After removing them, the oil was wiped off and rubbed with SUS tweezers to the extent that they were not damaged.
- DOA test oil
- the resin portion was not The substrate was not peeled.
- the resin portion was not covered by the substrate in the above rubbing test. Peeled off.
- the resin composition was made to have a difference of at least 1.0 in absolute value between the solubility parameter of the base resin of the ink 12 and the solubility parameter of the lubricating oil.
- the wear of the dynamic pressure generating section A due to the swelling of the bearings can be suppressed, and stable bearing performance can be secured over a long period of time.
- thermosetting resin can also be used as the base resin.
- thermosetting resin is not particularly limited as long as it has heat resistance.
- examples thereof include phenol resin, epoxy resin, alkyd resin, melamine resin, and unsaturated polyester resin. be able to. These can be used after appropriately dissolving them in a solvent.
- Various additives such as a thermosetting initiator may be added to these as needed.
- thermosetting resin there is no particular limitation as long as it can dissolve the thermosetting resin.
- an alcohol-based solvent such as ethanol
- a ketone-based solvent such as methyl ethyl ketone, or an ester-based solvent such as butyl acetate can be used.
- an epoxy resin an aromatic solvent such as toluene-xylene or a ketone-based solvent can be used.
- ester solvents When an alkyd resin is used, aromatic solvents and ester solvents can be preferably used.
- FIG. 6 is a diagram showing a schematic configuration of a molding apparatus using a thermosetting resin as the base resin of the ink 12.
- the light source 21 is unnecessary.
- minute droplets of the ink 12 land on a predetermined position on the outer peripheral surface of the material 2a '.
- On the outer peripheral surface of the material 2a ′ for example, a herringbone-shaped dynamic pressure groove in which a back portion Aa covered with an aggregate of ink microdroplets and a dynamic pressure groove Ab that is covered with ink are arranged.
- a generation part A is formed.
- each nozzle 14 the supply and stop of the ink 12 are switched as appropriate at a predetermined timing.
- the formation of the dynamic pressure groove pattern is performed in such a manner that it gradually progresses in the circumferential direction of the outer peripheral surface of the raw material 2a ′ with the rotation of the raw materials 2a.
- the raw material 2a ′ is charged into a molding apparatus in a pre-heated state, and the ink 12 is cured from the bonding interface simultaneously with landing. desirable.
- the droplets of the ink 12 are cured at the same time as landing, so that the ink 12 can be prevented from peeling off or falling off due to the rotation of the material 2a ', and a highly accurate dynamic pressure generating portion can be efficiently formed.
- the ink 12 when the ink 12 is hardened only by ultraviolet rays as in the molding apparatus shown in Fig. 1, the surface tension of the ink 12 progresses, so that the material 2a 'remains in an unstable state at the interface. , Ie, the printing is advanced. In addition, since the surface is first cured, an escape route for gas or the like contained in the ink 12 is lost, and there is a possibility that the ink 12 is cured with the gas or the like mixed therein. If the material 2a 'is used in this state by incorporating it into a hydrodynamic bearing device, the temperature etc. during the operation of the bearing will cause the gas etc.
- any of so-called external heating and internal heating is used as a method of heating the material 2a '.
- External heating refers to a heating method in which a heat source arranged outside a substance (here, material 2a ') gradually heats the surface from the inside to the inside using heat conduction, radiation, convection, etc.
- heat conduction, radiation, convection, etc. For example, heating by direct fire, hot air, steam, electric heat and the like can be mentioned.
- internal heating refers to a heating method in which the inside and outside are heated simultaneously and in parallel by the substance itself generating heat, such as electromagnetic wave heating using high frequency or microwave. it can.
- the form in which the dynamic pressure generating portion is formed using the material 2a 'that has been heated in advance has been described as an example.
- a heat source is arranged in the molding apparatus, and printing is performed while heating.
- a dynamic pressure generating part can also be formed.
- both heating methods can be used together. In this case, the curing of the resin can be advanced both at the surface and at the interface of the landed ink droplets, thereby reducing cycle time and reducing manufacturing costs. Can be reduced.
- the ink 12 is thermally cured.
- this thermal curing can be used in combination with light curing, preferably ultraviolet curing, whereby the curing speed of the ink 12 can be further increased. Can be faster. If only UV curing is used (see Fig. 1), the shape and arrangement of the light guides need to be considered in order to cure the ink uniformly. Since these are arranged for the purpose of improving the curing speed, this kind of consideration is not necessary.
- an ink obtained by adding a curing agent (a polymerization initiator, a polymerization initiation catalyst, and the like) to a base resin is used.
- a radical polymerizable monomer, a radical polymerizable oligomer, and a cationic polymerizable monomer can be preferably used.
- a cationic polymerization monomer such as an alicyclic epoxy resin exemplified by Celloxide 2021P, and an alicyclic epoxy diluent exemplified by Celloxide 3000 (both manufactured by Daiceli Gakugaku Kogyo Co., Ltd.) Can be used.
- the curing agent to be added to the base resin includes, in addition to the above-described heat-curing initiator, for example, San-Aid SI-H40 and San-Aid SI-L150 (both from Sanshin Iridaku Kogyo Co., Ltd.) A mixture of a thermosetting initiator exemplified in U.S.A.
- FIG. 7 shows a specific configuration example of the hydrodynamic bearing device 1 incorporating the shaft member 2 manufactured in the above process.
- the hydrodynamic bearing device 1 includes a shaft member 2 having a shaft portion 2a at the center of rotation, a housing 7 having a bottomed cylindrical shape, and fixed to the inner peripheral surface of the housing 7, and the shaft portion 2a is inserted into the inner periphery thereof. It comprises a possible cylindrical bearing sleeve 8 and a seal 9 fixed in the opening of the housing 7.
- the shaft member 2 is composed of a solid shaft-shaped shaft portion 2a and a flange portion 2b provided integrally or separately at one end thereof.
- the flange portion 2b is formed separately.
- a herringbone-shaped dynamic pressure generating portion A including a plurality of dynamic pressure grooves Ab and a convex back portion Aa that defines the dynamic pressure grooves Ab is provided on the outer peripheral surface 2al of the shaft portion 2a. It is formed two places apart in the axial direction.
- the dynamic pressure generating portion A is formed through the steps of printing on the surface of the material 2a 'by the inkjet method and curing the ink as described above.
- the dynamic pressure groove Ab is formed to be asymmetric in the axial direction with respect to the axial center m, and the axial dimension XI of the upper area around the axial center m is lower. Is larger than the axial dimension X2. Therefore, when the shaft member 2 rotates, the lubricating oil drawing force (bombing force) by the dynamic pressure groove Ab is relatively larger in the upper dynamic pressure generating portion A than in the lower symmetrical dynamic pressure generating portion A. Become.
- the number of the dynamic pressure generating portions A can be formed arbitrarily, and can be formed at one location or at three or more locations in the axial direction.
- a first thrust bearing surface provided with, for example, a spiral dynamic pressure generating portion composed of a dynamic pressure groove and a back portion defining the dynamic pressure groove.
- B and the second thrust bearing surface C are formed.
- the first thrust bearing surface B is opposed to a lower end surface 8b of a bearing sleeve 8 described later via a first thrust bearing gap.
- the second thrust bearing surface C faces an upper end surface 7c1 of a bottom portion 7c of the housing 7 described later via a second thrust bearing gap.
- the dynamic pressure generating parts of the first and second thrust bearing surfaces B and C are: In addition to forming by a common means such as press working, it can be formed through the steps of printing with the ink 12 and curing thereof using a forming apparatus shown in FIG.
- the thrust bearing surfaces B and C having these dynamic pressure generating portions are similar to the lower end surface 8b of the bearing sleeve 8 and the upper end surface 7cl of the bottom portion 7c which are opposed to these end surfaces only by the end surfaces 2bl and 2b2 of the flange portion 2b. It can also be formed by the following method.
- the bearing sleeve 8 is made of, for example, a porous body of sintered metal, particularly a porous body of an oil-impregnated sintered metal obtained by impregnating a sintered metal mainly containing copper with lubricating oil (or lubricating grease). It is formed in a shape.
- the shaft member 2 is inserted into the inner peripheral surface 8a of the bearing sleeve 8.
- the inner peripheral surface 8a of the bearing sleeve 8 is formed as a smooth cylindrical surface, and faces the dynamic pressure generating portion A formed on the outer peripheral surface 2al of the shaft member 2 through the radial bearing gap.
- the housing 7 has a substantially cylindrical side part 7b having both ends opened and a bottom part 7c as constituent members.
- the side portion 7b and the bottom portion 7c are separate members.
- the side portion 7b is formed into a substantially cylindrical shape by injection molding of a resin composition
- the bottom portion 7c is formed into a substantially circular shape by press molding of a soft metal. It is formed into a column shape.
- a bottomed cylindrical housing 7 having one end sealed is formed.
- the side part 7b and the bottom part 7c of the housing 7 can be integrally formed of a resin composition or a metal material.
- the seal member 9 is formed in a ring shape from a metal material or a resin material.
- the seal member 9 is formed separately from the housing 7, and is fixed to the upper end opening 7a of the side portion 7b of the housing 7 by means of press-fitting, bonding, or the like.
- the inner peripheral surface 9a of the seal member 9 has a tapered shape with an upward force, and the diameter between the inner peripheral surface 9a and the outer peripheral surface 2al of the shaft portion 2a opposed to the inner peripheral surface 9a is increased.
- annular seal space S whose radial dimension gradually increases upward is formed.
- lubricating oil as a lubricating fluid is injected into the internal space of the dynamic pressure bearing device 1 sealed by the seal member 9, and the inside of the dynamic pressure bearing device 1 is filled with the lubricating oil. In this state, the oil level of the lubricating oil is maintained within the range of the seal space S.
- the first thrust bearing surface B formed on the upper end surface 2bl of the flange portion 2b of the shaft member 2 faces the lower end surface 8b of the bearing sleeve 8 via the first thrust bearing gap.
- the second thrust bearing surface C formed on the lower end surface 2b2 of the portion 2b faces the upper end surface 7c1 of the bottom 7c of the housing 7 via the second thrust bearing gap.
- the pressure of the lubricating oil filled in the thrust bearing gap becomes extremely large during the operation of the bearing for some reason, and the pressure between the lubricating oil and the seal space S increases. There may be differences. A strong pressure difference may cause air bubbles in the lubricating oil and the resulting leakage or vibration of the lubricating oil. In order to prevent such a situation, a circulation path 10 for communicating the thrust bearing gap with the outside air is formed inside the bearing device. By providing the circulation path 10, the pressure between the seal space S and the thrust bearing gap can be balanced, and the above-described problem due to the pressure difference can be avoided.
- the circulation path 10 includes a circulation groove 10a provided between the outer peripheral surface of the bearing sleeve 8 and the inner peripheral surface of the housing 7, an upper end surface 8c of the bearing sleeve 8, and a lower end surface 9b of the seal member 9.
- the upper end force of the circulation groove 10a also includes a radial groove 10b that passes through the seal space S.
- FIG. 7 illustrates a case where the circulation groove 10 a is formed on the outer periphery of the bearing sleeve 8 .
- the circulation groove 10 a may be formed on the inner peripheral surface of the side portion 7 b of the housing 7. .
- FIG. 11 conceptually shows a configuration example of a spindle motor for information equipment incorporating the dynamic pressure bearing device 1 shown in FIG.
- This information device spindle motor is used in a disk drive device such as an HDD, and includes a dynamic pressure bearing device 1, a disk hub 3 attached to a shaft member 2 of the dynamic pressure bearing device 1,
- a bracket 6 includes a stator coil 4 and a rotor magnet 5 opposed to each other via a gap.
- the stator coil 4 is attached to the outer periphery of the bracket 6, and the rotor magnet 5 is attached to the inner periphery of the disk hub 3.
- the disk hub 3 holds one or more disks D such as magnetic disks on the outer periphery.
- the housing 7 of the hydrodynamic bearing device 1 is mounted on the inner periphery of the bracket 6.
- FIG. 8 shows a dynamic pressure shaft in which the bearing member 27 is formed by integrating a portion corresponding to the bearing sleeve 8 and a portion corresponding to the housing 7 in the embodiment of the dynamic pressure bearing device 1 shown in FIG. 6 shows a receiving device 31.
- the same reference numerals are given to members and configurations that perform the same functions as those of the hydrodynamic bearing device 1 shown in FIG. 7, and redundant description is omitted.
- the bearing member 27 can be formed by injection molding of a forged resin material of a metal material or MIM molding.
- the illustrated bearing member 27 includes a sleeve portion 27a, a seal mounting portion 27b above the sleeve portion 27a, and a sealing portion 27c below the sleeve portion 27a.
- the inner peripheral surface 27al of the sleeve portion 27a has a smaller diameter than the inner peripheral surface 27bl of the seal mounting portion 27b and the inner peripheral surface 27cl of the sealing portion 27c, and faces the two dynamic pressure generating portions A of the shaft member 2.
- the seal member 27 is fixed to the inner peripheral surface 27bl of the seal mounting portion 27b of the bearing member 27 by the press-fitting, bonding, or a combination of the two. ing.
- the bottom portion 7c has a cylindrical portion 71 protruding upward on the outer periphery, and the cylindrical portion 28a is brought into contact with the end surface 27al of the sleeve portion 27a.
- a radial groove 1 Oc is formed between the cylindrical portion 71 of the bottom portion 7c and the end surface 27al of the sleeve portion 27a, and the first and second thrusts are formed through the radial groove 10c, the circulation groove 10a, and the radial groove 10b.
- the thrust bearing gap between the bearings T1 and T2 communicates with the seal space S.
- the dynamic pressure generating section A is formed on the inner peripheral surface of the bulb section 27a through the above-described printing process using an ink-jet method or the like and the ink curing process.
- the dynamic pressure generating portions of the thrust bearing surfaces B and C formed on both end surfaces 2bl and 2b2 of the flange portion 2b can be formed in the same process by using the forming device shown in FIG.
- FIG. 9 shows another embodiment of the dynamic pressure bearing device.
- the dynamic pressure bearing device 41 shown in FIG. 9 mainly has a point that the seal space S is formed between the outer peripheral surface 7b2 of the upper end of the housing 7 and the inner peripheral surface 3bl of the cylindrical portion 3b of the disk hub 3. 7 is different from the embodiment shown in FIG. 7 in that a second thrust bearing portion T2 is formed between an upper end surface 7bl of the nozzle 7 and a lower end surface 3al of the plate portion 3a constituting the disk hub 3.
- the second thrust bearing surface C of the second thrust bearing portion T2 has a force formed on the upper end surface 7b1 of the housing 7 in a molding die for molding the housing 7, for example, the second thrust bearing.
- the dynamic pressure generating portion can be formed simultaneously with the molding of the housing 7.
- the dynamic pressure generating portion A is formed on the outer peripheral surface of the shaft portion 2a of the shaft member 2 or the inner peripheral surface of the bearing sleeve 8 through the printing step and the ink curing step by the above-described ink jet method or the like.
- FIG. 10 shows another embodiment of the dynamic pressure bearing device 1.
- the thrust bearing portion T of the dynamic pressure bearing device 51 is located on the opening side of the housing 7 and supports the shaft member 2 in a non-contact manner with the bearing sleeve 8 in one thrust direction.
- a flange portion 2b is provided above the lower end of the shaft member 2, and a thrust bearing portion T is formed between a lower end surface 2b2 of the flange portion 2b and an upper end surface 8c of the bearing sleeve 8.
- a seal member 9 is mounted on the inner periphery of the opening of the housing 7, and a seal space S is formed between the inner peripheral surface 9a of the seal member 9 and the outer peripheral surface 2al of the shaft portion 2a of the shaft member 2.
- the lower end surface 9b of the sealing member 9 is opposed to the upper end surface 2bl of the flange portion 2b via an axial gap, and when the shaft member 2 is displaced upward, the upper end surface 2bl of the flange portion 2b is sealed.
- the shaft member 2 is prevented from coming off by engaging with the lower end surface 9b of the member 9.
- the outer peripheral surface of the shaft portion 2a of the shaft The dynamic pressure generating portion A is formed on the inner peripheral surface of the probe 8 through the above-described printing process using an ink-jet method or the like and a curing process of the ink.
- the dynamic pressure generating portion B on the upper end surface 8c of the bearing sleeve 8 can be formed in the same manner by the above-mentioned printing step and hardening step.
- the configuration of the dynamic pressure generating section is not limited to this.For example, use multi-arc bearings, step bearings, tapered bearings, tapered flat bearings, etc. as the radial bearings Rl and R2. Step and pocket bearings, teno pocket bearings, tapered flat bearings, pivot bearings, etc. can also be used as the thrust bearings Tl, # 2.
- the radial bearing portions Rl and R2 are configured by multi-arc bearings
- one or both of the radial bearing surface A on the inner circumference of the bearing sleeve 7 and the outer circumference of the shaft member 2 are formed by multi-arc surfaces
- the radial bearing gap between each arc surface and its opposing surface is a wedge-shaped gap that decreases in the rotational direction.
- the multi-arc surface as the dynamic pressure generating portion can be formed through a printing process and a curing process by an inkjet method using the forming device shown in FIG.
- the above description shows a configuration in which two radial bearing portions are provided in the axial direction.
- the number of radial bearing portions is arbitrary, and one radial bearing portion is provided at one location or three or more locations in the axial direction. A little monster.
- lubricating oil was exemplified as the fluid (lubricating fluid) filling the inside of the dynamic pressure bearing device 1.
- dynamic pressure may be generated in each bearing gap.
- a fluid that can be used for example, a magnetic fluid or a gas such as air can also be used.
- FIG. 1 is a cross-sectional view showing a schematic structure of an inkjet type molding apparatus.
- FIG. 2 is a cross-sectional view showing a schematic configuration of a hydrodynamic bearing device.
- FIG. 2 (a) shows a case where a thrust bearing portion T is constituted by a pivot bearing
- FIG. 2 (b) shows a thrust bearing portion Tl and ⁇ 2 by a dynamic pressure bearing. Shows the case of configuration.
- FIG. 3 is a side view showing another example of the printing process in the molding apparatus.
- FIG. 4 is an enlarged sectional view of a material surface of a shaft member.
- FIG. 5 is a cross-sectional view illustrating a schematic structure of an inkjet type molding apparatus.
- FIG. 6 is a cross-sectional view showing a schematic structure of an inkjet type molding apparatus.
- FIG. 7 is a cross-sectional view showing an embodiment of the dynamic pressure bearing device according to the present invention.
- FIG. 8 is a cross-sectional view showing an embodiment of the hydrodynamic bearing device according to the present invention.
- FIG. 9 is a cross-sectional view showing an embodiment of the dynamic pressure bearing device according to the present invention.
- Fig. 10 is a cross-sectional view showing an embodiment of the dynamic pressure bearing device according to the present invention.
- FIG. 11 is a cross-sectional view of a spindle motor incorporating a dynamic pressure bearing device. Explanation of symbols
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- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Power Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/592,429 US20070242908A1 (en) | 2004-04-20 | 2005-04-12 | Forming Method of Dynamic Pressure Generating Portion and Fluid Dynamic Bearing Device |
Applications Claiming Priority (10)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004-124645 | 2004-04-20 | ||
JP2004124645 | 2004-04-20 | ||
JP2004-279903 | 2004-09-27 | ||
JP2004279903A JP2006090520A (ja) | 2004-09-27 | 2004-09-27 | 樹脂組成物 |
JP2004-295263 | 2004-10-07 | ||
JP2004295263A JP2005331100A (ja) | 2004-04-20 | 2004-10-07 | 動圧発生部の成形方法 |
JP2005-014598 | 2005-01-21 | ||
JP2005014598A JP2006200667A (ja) | 2005-01-21 | 2005-01-21 | 動圧軸受装置 |
JP2005-020077 | 2005-01-27 | ||
JP2005020077A JP2006207682A (ja) | 2005-01-27 | 2005-01-27 | 動圧軸受装置およびその製造方法 |
Publications (2)
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WO2005101985A2 true WO2005101985A2 (ja) | 2005-11-03 |
WO2005101985A3 WO2005101985A3 (ja) | 2006-01-12 |
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PCT/JP2005/007092 WO2005101985A2 (ja) | 2004-04-20 | 2005-04-12 | 動圧発生部の成形方法および動圧軸受装置 |
Country Status (2)
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US (1) | US20070242908A1 (ja) |
WO (1) | WO2005101985A2 (ja) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
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JP2006283915A (ja) * | 2005-04-01 | 2006-10-19 | Ntn Corp | 流体軸受装置 |
US8453665B2 (en) * | 2007-03-15 | 2013-06-04 | The University Of Akron | Self-acting self-circulating fluid system without external pressure source and use in bearing system |
CN101855678B (zh) * | 2007-10-12 | 2015-11-25 | 住友电工运泰克株式会社 | 绝缘电线、使用了该绝缘电线的电线圈、以及发动机 |
US8242651B2 (en) * | 2009-09-25 | 2012-08-14 | Siemens Industry, Inc. | Self-contained bearing lubrication system operating on oil ring lubricated by nozzle |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS5735682A (en) * | 1980-08-08 | 1982-02-26 | Nippon Seiko Kk | Formation of groove for generating dynamic pressure |
JPH04301086A (ja) * | 1991-03-29 | 1992-10-23 | Kenseidou Kagaku Kogyo Kk | 細い金属棒表面に微細な溝を有する金属シャフトの製法 |
JPH0544055A (ja) * | 1991-08-08 | 1993-02-23 | Canon Inc | 動圧流体軸受の溝加工方法 |
JPH0663781A (ja) * | 1992-08-11 | 1994-03-08 | Kenseidou Kagaku Kogyo Kk | 空軸及び空気軸受の製法 |
JPH07310733A (ja) * | 1994-05-13 | 1995-11-28 | Sankyo Seiki Mfg Co Ltd | 動圧軸受装置 |
WO2003072967A1 (fr) * | 2002-02-28 | 2003-09-04 | Fujitsu Limited | Procede de fabrication de palier sous pression dynamique, palier sous pression dynamique, et dispositif de fabrication de palier sous pression dynamique |
-
2005
- 2005-04-12 US US10/592,429 patent/US20070242908A1/en not_active Abandoned
- 2005-04-12 WO PCT/JP2005/007092 patent/WO2005101985A2/ja active Application Filing
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WO2005101985A3 (ja) | 2006-01-12 |
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