WO2016152474A1 - Élément palier, dispositif de palier de pression dynamique à fluide le comportant, et procédé de fabrication d'élément palier - Google Patents

Élément palier, dispositif de palier de pression dynamique à fluide le comportant, et procédé de fabrication d'élément palier Download PDF

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Publication number
WO2016152474A1
WO2016152474A1 PCT/JP2016/056947 JP2016056947W WO2016152474A1 WO 2016152474 A1 WO2016152474 A1 WO 2016152474A1 JP 2016056947 W JP2016056947 W JP 2016056947W WO 2016152474 A1 WO2016152474 A1 WO 2016152474A1
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WO
WIPO (PCT)
Prior art keywords
bearing
bearing member
intermediate sleeve
sintered
cylindrical
Prior art date
Application number
PCT/JP2016/056947
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English (en)
Japanese (ja)
Inventor
和慶 原田
冬木 伊藤
稔明 丹羽
哲弥 栗村
Original Assignee
Ntn株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Priority claimed from JP2015059691A external-priority patent/JP2016180427A/ja
Priority claimed from JP2015062504A external-priority patent/JP2016180496A/ja
Application filed by Ntn株式会社 filed Critical Ntn株式会社
Publication of WO2016152474A1 publication Critical patent/WO2016152474A1/fr

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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
    • 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
    • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
    • 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
    • F16C33/14—Special methods of manufacture; Running-in
    • 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
    • F16C2380/00—Electrical apparatus
    • F16C2380/26—Dynamo-electric machines or combinations therewith, e.g. electro-motors and generators
    • 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 bearing member used in a fluid dynamic pressure bearing device and a method for manufacturing the same, and particularly to a bearing member having a plurality of sintered bodies.
  • Sintered metal bearing members are usually manufactured through compacting (forming), sintering, and re-pressure (sizing).
  • the core rod is inserted into the inner periphery of the sintered body, and further, the sintered body is pressed from both sides in the axial direction. Molding to the dimensional accuracy of
  • each sintered bearing can be accurately molded.
  • FIG. 3 of Patent Document 1 below shows a bearing member (composite porous bearing) formed by combining a plurality of sintered bodies. Specifically, after each of the plurality of sintered bodies is formed, they are put in a sizing mold in a combined state, and pressed from above and below with a core rod passed through the inner periphery. As a result, a plurality of sintered bodies are firmly joined, and at the same time, the bearing surface of each sintered body is finished and centered. In this way, by fixing the plurality of sintered bodies by sizing and simultaneously performing finishing and centering on the plurality of bearing surfaces, the relative direction of the plurality of bearing surfaces in the radial direction can be achieved without increasing the number of man-hours. The position can be set with high accuracy.
  • each sintered body is compressed in the axial direction, so the amount of deformation in the axial direction of the entire bearing member increases, resulting in the following problems May occur.
  • (1) The total axial length of the bearing members and the axial intervals (bearing spans) of a plurality of bearing surfaces vary from product to product.
  • (2) A sufficient pressing force is not applied to each sintered body, and the dimensional accuracy of each sintered body, particularly the inner diameter of the bearing surface, varies from product to product.
  • the pressing force applied to each sintered body becomes non-uniform, and the inner diameter dimensions of a plurality of bearing surfaces differ in each bearing member.
  • the first problem to be solved by the present invention is to increase the dimensional accuracy of a bearing member having a plurality of sintered bodies.
  • a fluid dynamic pressure bearing device has features such as high-speed rotation, high rotation accuracy, and low noise. Therefore, a spindle motor incorporated in a disk drive device such as an HDD and a fan motor incorporated in an electronic device. Alternatively, it is suitably used as a bearing device for a motor such as a polygon scanner motor incorporated in a laser beam printer.
  • a fluid dynamic pressure bearing device includes a bearing member having a cylindrical radial bearing surface on an inner periphery, a shaft member inserted into the inner peripheral surface of the bearing member, a radial bearing surface of the bearing member, and an outer peripheral surface of the shaft member. And a radial bearing portion that supports the shaft member in a radial direction so as to be relatively rotatable with a lubricating film (for example, an oil film) of fluid generated in a radial bearing gap therebetween.
  • a radial bearing surface is provided at two locations spaced apart in the axial direction on the inner peripheral surface, and a so-called cylindrical surface (medium escape portion) having a larger diameter than the radial bearing surface is provided between both radial bearing surfaces.
  • a middle relief structure is employed.
  • the bearing member having a center relief structure may be configured by a single cylindrical body or may be configured by combining and integrating a plurality of cylindrical bodies arranged in an axial direction.
  • a cylindrical body having a radial bearing surface a cylindrical body made of a sintered metal excellent in workability (mass productivity) and oil film forming ability in the radial bearing gap is used.
  • FIG. 1 of Patent Document 1 described above discloses a bearing member in which a middle escape portion is formed by joining two cylindrical bodies arranged in an axial direction.
  • the bearing member 200 is obtained by integrating a first cylindrical body 210 and a second cylindrical body 220 made of sintered metal by a coupling portion 204.
  • a first radial bearing surface 201 is provided on the inner periphery of the first cylindrical body 210, and a second radial bearing surface 202 and a diameter larger than those of the radial bearing surfaces 201 and 202 are provided on the inner periphery of the second cylindrical body 220.
  • a cylindrical surface (medium escape portion) 203 are provided.
  • the bearing member 200 is finished into a finished product shape using a sizing mold 230 shown in FIGS. 16A to 16C. Specifically, first, as shown in FIG. 16A, a cylindrical small diameter provided at the upper end of the second cylindrical body 220 (strictly, the cylindrical material finished to the second cylindrical body 220 shown in FIG. 15 by sizing). The outer peripheral surface 221 and the cylindrical large-diameter inner peripheral surface 211 provided at the lower end of the first cylindrical body 210 (strictly, the cylindrical material finished to the first cylindrical body 210 shown in FIG. 15 by sizing) are fitted. To construct an assembly. With the core rod 231 inserted into the inner periphery of the assembly, as shown in FIG.
  • the assembly, the core rod 231 and the upper punch 233 are integrally lowered to press-fit the assembly into the inner periphery of the die 232. Then, as shown in FIG. 16C, the assembly, the core rod 231, and the upper punch 233 are further lowered, and the assembly is pressed in the axial direction by the upper punch 233 and the lower punch 234. As described above, the inner peripheral surfaces of the cylindrical bodies 210 and 220 are pressed against the core rod 231 to form the radial bearing surfaces 201 and 202, and between the cylindrical bodies 210 and 220 (particularly between the radial bearing surfaces 201 and 202). Coaxial out at is performed.
  • both the cylindrical bodies 210 and 220 are pressed from the inner diameter side and the outer diameter side by the core rod 231 and the die 232, and the large diameter inner peripheral surface 211 of the first cylindrical body 210 and the small diameter outer periphery of the second cylindrical body 220.
  • bonds both the cylindrical bodies 210 and 220 is formed in close contact with the surface 221.
  • each cylindrical body constituting the bearing member 200 is a mass-produced part, it is not always formed in the same shape and size. Actually, the shape and size of each part of the first cylindrical body 210 and the second cylindrical body 220 vary from product to product. Therefore, when the bearing member 200 is obtained, for example, as shown in FIG. 17A, a first cylindrical body 210 having a different thickness in each circumferential direction due to uneven thickness may be used. For ease of understanding, the degree of uneven thickness is exaggerated in the illustrated example.
  • both cylinders 210 and 220 are sized in a state in which both cylinders 210 and 220 are fitted in advance (concave fitting)
  • the second cylinder The presence of the body 220 restricts the movement of the first cylindrical body 210 inward in the radial direction. For this reason, the shaping
  • the radial bearing surface 201 having the shape and accuracy cannot be formed. In this case, the required coaxiality between the radial bearing surfaces 201 and 202 cannot be ensured (see FIG. 17B).
  • the second problem to be solved by the present invention is a combination of a plurality of cylindrical bodies arranged in an axial direction, and a pair of radial bearing surfaces separated in the axial direction on the inner periphery. It is possible to properly secure the shape and dimensional accuracy of each radial bearing surface and the coaxiality between both radial bearing surfaces while appropriately connecting the cylindrical bodies in the bearing member for the fluid dynamic bearing device having Thus, it is possible to realize a fluid dynamic pressure bearing device having excellent bearing performance in the radial direction.
  • the first invention of the present application includes a plurality of sintered bodies having bearing surfaces on an inner peripheral surface, and an intermediate sleeve disposed between the axial directions of the plurality of sintered bodies.
  • the first invention of the present application forms a plurality of cylindrical sintered bodies and an intermediate sleeve having a smaller amount of axial load deformation than each sintered body. And inserting the assembly into the inner periphery of the die in a state where the core rod is inserted into the inner periphery of the assembly composed of the plurality of sintered bodies and the intermediate sleeve disposed between the plurality of sintered bodies. By pressing the assembly from both sides in the axial direction, the inner peripheral surfaces of the plurality of sintered bodies are pressed against the outer peripheral surface of the core rod, and a bearing surface is formed on the inner peripheral surfaces of the plurality of sintered bodies.
  • a method of manufacturing a bearing member having a process is provided.
  • the “load deformation amount” means a deformation amount including elastic deformation and plastic deformation when a predetermined load (for example, a load during sizing) is applied to each member.
  • the intermediate sleeve disposed between the axial directions of the plurality of sintered bodies has a smaller axial load deformation amount than the sintered body, thereby reducing the axial deformation amount of the intermediate sleeve due to compression during sizing. Can be suppressed.
  • the deformation amount of the entire bearing member is suppressed, variations in the axial length of the bearing member and axial intervals (bearing spans) of a plurality of bearing surfaces for each product can be suppressed.
  • the intermediate sleeve becomes difficult to be compressed, a sufficient pressing force can be applied to each sintered body, so that the dimensional accuracy of each sintered body, particularly the accuracy of the inner diameter of the bearing surface can be increased.
  • by suppressing the deformation amount of the intermediate sleeve it is possible to apply a pressing force uniformly to each sintered body, and thus it is possible to suppress differences in the inner diameter dimensions of the plurality of bearing surfaces in each bearing member.
  • the intermediate sleeve is formed of a melted material, in particular, a melted material made of the same metal as the plurality of sintered bodies (the main component is the same metal), the amount of load deformation can be made smaller than each sintered body. It becomes possible.
  • the load deformation amount is a deformation amount including plastic deformation, it is a parameter different from the elastic modulus representing the ratio between the load and the deformation amount in the elastic deformation.
  • the elastic modulus of one member is greater than that of the other member, the deformation amount of both rarely reverses in the plastic region. Therefore, in practice, one member having a large elastic modulus is the other member. It can be considered that the load deformation amount is smaller than that. Therefore, if the intermediate sleeve is formed of a material having a larger elastic modulus than each sintered body, the load deformation amount in the axial direction of the intermediate sleeve is usually smaller than that of each sintered body.
  • a radial dynamic pressure generating portion such as a dynamic pressure groove may be formed on the bearing surfaces of the plurality of sintered bodies.
  • a radial dynamic pressure generating portion can be formed on the bearing surfaces of a plurality of sintered bodies by providing a forming die on the outer peripheral surface of the core rod and pressing the inner peripheral surfaces of the plurality of sintered bodies against the forming die. .
  • the load deformation amount of the intermediate sleeve is small as described above, the inner peripheral surfaces of the plurality of sintered bodies are pressed against the forming die on the outer peripheral surface of the core rod with sufficient force. Molding accuracy is increased.
  • a method of manufacturing a bearing member includes forming the pair of radial bearing surfaces and providing a middle relief portion having a larger diameter than the radial bearing surfaces between the axial directions of the radial bearing surfaces.
  • a concave portion is provided in advance on one end surface of two cylindrical bodies adjacent in the axial direction, and a flat surface is provided on the other end surface of the two cylindrical bodies adjacent in the axial direction.
  • the “radial bearing surface” as used in the present invention means a surface that forms a radial bearing gap with the outer peripheral surface of the shaft to be supported, and a dynamic pressure generating portion such as a dynamic pressure groove is formed on this surface. It doesn't matter whether it is done or not.
  • the present invention by pressing a plurality of cylindrical bodies from both sides in the axial direction, sizing is performed, and at the same time, a recess provided in one of the two adjacent cylindrical bodies is made to be adjacent to two adjacent cylindrical bodies. Press against a flat surface provided on the other of the cylinders. As a result, the flat surface is plastically deformed, and a convex portion that is in close contact with the concave portion is formed on the flat surface. In this case, the concave portion and the flat surface are not engaged in the radial direction at the start of compression.
  • the first cylindrical body made of sintered metal disposed at one end in the axial direction and the second cylindrical body made of sintered metal disposed at the other end in the axial direction are arranged continuously in the axial direction.
  • the bearing member is provided on a concave portion provided on one end surface of two cylindrical bodies adjacent in the axial direction and on the other end surface of the two cylindrical bodies adjacent in the axial direction. It has a convex part that is formed by plastic deformation by pressure welding and that is in close contact with the concave part.
  • the concave portion is provided on the end surface of the first cylindrical body, and the convex portion formed by plastic deformation by pressure contact of the concave portion is provided on the end surface of the second cylindrical body.
  • the plurality of cylindrical bodies have a third cylindrical body arranged between the first cylindrical body and the second cylindrical body in the axial direction.
  • the concave portions are provided on both end surfaces of the third cylindrical body in the axial direction, and the convex portions formed by plastic deformation by pressure contact of the concave portions are formed on the end surfaces of the first cylindrical body and the second cylindrical body.
  • a middle escape portion can be provided on the inner peripheral surface of the third cylindrical body.
  • Such a third cylindrical body is obtained, for example, by forming with a melted material such as stainless steel or brass.
  • a dynamic pressure generating portion such as a dynamic pressure groove can be provided on both radial bearing surfaces.
  • This dynamic pressure generating portion can be molded simultaneously with sizing of a plurality of cylindrical bodies.
  • a bearing member having a dynamic pressure generating portion on a radial bearing surface is generally a bearing member having no dynamic pressure generating portion on the radial bearing surface (a bearing having a radial bearing surface formed on a smooth cylindrical surface). Compared to the member), it is used in a region where the gap width of the radial bearing gap formed between the outer peripheral surface of the shaft to be supported is small and the coaxiality required between the two radial bearing surfaces is relatively Becomes smaller.
  • the coaxiality between the two radial bearing surfaces can be appropriately ensured as described above. Therefore, the present invention can achieve further effects in the bearing member in which the dynamic pressure generating portion is provided on the radial bearing surface.
  • a thrust bearing surface that forms a thrust bearing gap between the end surface of the shaft to be supported is provided on at least one of the end surface of the first cylinder and the end surface of the second cylinder. You can also. This thrust bearing surface can also be formed simultaneously with the sizing of the plurality of cylindrical bodies.
  • the cylindrical bodies adjacent in the axial direction are appropriately coupled to each other, and the degree of coaxiality between the radial bearing surfaces provided at two positions separated in the axial direction. Is adequately secured. Therefore, the bearing member, the shaft member inserted in the inner periphery of the bearing member, the housing in which the bearing member is fixed to the inner periphery, and the radial bearing gap between the radial bearing surface of the bearing member and the outer peripheral surface of the shaft member
  • the fluid dynamic pressure bearing device including the radial bearing portion that supports the shaft member in a non-contact manner with the fluid pressure generated in the above-described manner has low torque and excellent bearing rigidity (moment rigidity).
  • the fluid dynamic pressure bearing device including the bearing member according to the present invention can be used as a bearing for a relatively large motor (for example, a fan motor for a server).
  • the dimensional accuracy of the bearing member formed by combining a plurality of sintered bodies and the intermediate sleeve can be improved. it can.
  • the bearing member composed of a plurality of cylindrical bodies arranged in the axial direction, the shape and dimensions of each radial bearing surface while appropriately connecting the cylindrical bodies.
  • the accuracy and the degree of coaxiality between both radial bearing surfaces can be appropriately ensured.
  • FIG. 10 It is a schematic sectional drawing of the fluid dynamic pressure bearing apparatus provided with the bearing member which concerns on one Embodiment of this-application 2nd invention. It is sectional drawing of the bearing member shown in FIG. It is sectional drawing which shows typically the sizing process included in the manufacturing process of the bearing member shown in FIG. 10, Comprising: The initial stage of the process is shown. It is sectional drawing which shows typically the sizing process included in the manufacturing process of the bearing member shown in FIG. 10, Comprising: It is a figure which shows the middle step of the process. It is sectional drawing which shows typically the sizing process included in the manufacturing process of the bearing member shown in FIG. 10, Comprising: It is a figure which shows the middle step of the process.
  • the fan motor shown in FIG. 1 is fixed to the fluid dynamic pressure bearing device 1, a motor base 6, a stator coil 5 fixed to the motor base 6, a rotor 3 having blades (not shown), and the rotor 3.
  • a stator magnet 5 and a rotor magnet 4 facing each other via a radial gap are provided.
  • the housing 7 of the fluid dynamic bearing device 1 is fixed to the inner periphery of the motor base 6, and the rotor 3 is fixed to one end of the shaft member 2 of the fluid dynamic bearing device 1.
  • the rotor magnet 4 when the stator coil 5 is energized, the rotor magnet 4 is rotated by the electromagnetic force between the stator coil 5 and the rotor magnet 4, and accordingly, the shaft member 2, the rotor 3, and The rotor magnet 4 rotates and, for example, an axial airflow is generated by the blades provided on the rotor 3.
  • the fluid dynamic bearing device 1 includes a bearing member 8 according to an embodiment of the present invention, a shaft member 2 inserted in the inner periphery of the bearing member 8, and a bearing member 8 on the inner peripheral surface. Is fixed, a seal member 9 disposed in one opening of the housing 7 in the axial direction, and a lid member 10 that closes the other opening of the housing 7 in the axial direction.
  • the opening side of the housing 7 in the axial direction is referred to as “upward” and the opposite side is referred to as “downward”.
  • the shaft member 2 is formed of a metal material such as stainless steel.
  • the shaft member 2 includes a shaft portion 2a and a flange portion 2b provided at the lower end of the shaft portion 2a.
  • a cylindrical surface 2a1 disposed on the inner periphery of the bearing member 8 and a tapered surface 2a2 disposed above the cylindrical surface 2a1 are provided on the outer peripheral surface of the shaft portion 2a.
  • the outer diameter of the shaft portion 2a (the outer diameter of the cylindrical surface 2a1) is, for example, about 1 to 4 mm.
  • the housing 7 is formed of a metal or a resin into a cylindrical shape (cylindrical in the illustrated example).
  • the bearing member 8 includes a first sintered body 81 and a second sintered body 82, and an intermediate sleeve 83 disposed between these axial directions.
  • the sintered bodies 81 and 82 have a cylindrical shape and are formed of a sintered metal, specifically, a copper-based, iron-based, or copper-iron-based sintered metal.
  • the sintered bodies 81 and 82 are formed of a sintered metal having the same composition.
  • radial bearing surfaces A1 and A2 are provided on the inner peripheral surfaces of the sintered bodies 81 and 82, respectively.
  • the first sintered body 81 has a small-diameter inner peripheral surface 81a and a large-diameter inner peripheral surface 81b provided therebelow, and a radial bearing surface in an upper region of the small-diameter inner peripheral surface 81a.
  • A1 is provided.
  • the second sintered body 82 has a small-diameter inner peripheral surface 82a and a large-diameter inner peripheral surface 82b provided thereabove, and a radial bearing surface A2 is provided in a lower region of the small-diameter inner peripheral surface 82a.
  • a radial bearing surface A2 is provided in a lower region of the small-diameter inner peripheral surface 82a.
  • Shoulder surfaces 81c and 82c are provided between the small diameter inner peripheral surfaces 81a and 82a and the large diameter inner peripheral surfaces 81b and 82b of the sintered bodies 81 and 82, respectively.
  • the shoulder surfaces 81c and 82c are flat surfaces orthogonal to the axial direction.
  • Herringbone-shaped dynamic pressure grooves 81a1 and 82a1 are formed on the radial bearing surfaces A1 and A2 as radial dynamic pressure generating portions, respectively.
  • the region indicated by cross-hatching in the figure represents a hill that is raised to the inner diameter side than the other regions.
  • the dynamic pressure grooves 81a1 and 82a1 are both symmetrical in the axial direction.
  • the radial bearing surfaces A1 and A2 including the dynamic pressure grooves 81a1 and 82a1 are collectively formed by sizing described later. Note that the composition or density of the plurality of sintered bodies 81 and 82 or both of them may be different.
  • an annular groove 81d1 and a plurality of radial grooves 81d2 provided at equal intervals in the circumferential direction are formed in the upper end surface 81d of the first sintered body 81.
  • a thrust bearing surface B is provided on the lower end surface 82 d of the second sintered body 82.
  • a spiral dynamic pressure groove 82d1 as shown in FIG. 4 is formed on the thrust bearing surface B as a thrust dynamic pressure generating portion.
  • the illustrated dynamic pressure groove 82d1 is a pump-in type that pushes the lubricating fluid into the inner diameter side. As shown in FIGS.
  • a plurality (three in the illustrated example) of axial grooves 81e1 and 82e1 are provided on the outer circumferential surfaces 81e and 82e of the sintered bodies 81 and 82 at equal intervals in the circumferential direction.
  • the numbers and positions of the axial grooves 81e1 and 82e1 and the radial grooves 81d2 are arbitrary, and any or all of them may be omitted if not particularly necessary.
  • the intermediate sleeve 83 has a smaller amount of load deformation in the axial direction than the sintered bodies 81 and 82.
  • the material of the intermediate sleeve 83 is selected so that the axial deformation amount of the intermediate sleeve 83 due to compression during sizing, which will be described later, is smaller than the axial deformation amount of each of the sintered bodies 81 and 82.
  • the intermediate sleeve 83 of the present embodiment is formed of a material having a larger elastic modulus than the sintered bodies 81 and 82, and is formed of, for example, a melted material. When the sintered metal is pressed, deformation occurs due to the collapse of the internal pores.
  • the load deformation amount of the molten metal is generally smaller than the load deformation amount of the sintered metal.
  • the intermediate sleeve 83 is formed of a melted material having the same main component as the sintered bodies 81 and 82, the above conditions can be easily satisfied.
  • the intermediate sleeve 83 may be formed of copper or a copper alloy (for example, brass).
  • the intermediate sleeve 83 may be formed of iron or an iron alloy (for example, mild steel).
  • the material of the intermediate sleeve 83 is not limited to the above as long as the load deformation amount is smaller than that of each of the sintered bodies 81 and 82.
  • the sintered bodies 81 and 82 are made of iron-based sintered metal.
  • the intermediate sleeve 83 may be made of brass in consideration of workability.
  • the intermediate sleeve 83 is not limited to a melted material, and is formed of, for example, a sintered metal having a higher elastic modulus than the sintered bodies 81 and 82 (for example, a sintered metal having a higher density than the sintered bodies 81 and 82). Also good.
  • the intermediate sleeve 83 has a substantially cylindrical shape, and its inner peripheral surface 83a is a cylindrical surface having no irregularities.
  • the inner peripheral surface 83a of the intermediate sleeve 83 has a larger diameter than the small-diameter inner peripheral surfaces 81a and 82a of the sintered bodies 81 and 82 (specifically, the cylindrical regions 81a2 and 82a2 other than the radial bearing surfaces A1 and A2).
  • the intermediate sleeve 83 has a large-diameter outer peripheral surface 83b and small-diameter outer peripheral surfaces 83c and 83d provided on both axial sides thereof.
  • Shoulder surfaces 83e and 83f are provided between the large-diameter outer peripheral surface 83b and the small-diameter outer peripheral surfaces 83c and 83d, respectively.
  • the shoulder surfaces 83e and 83f are flat surfaces orthogonal to the axial direction.
  • the large-diameter outer peripheral surface 83b of the intermediate sleeve 83 has a smaller diameter than the outer peripheral surfaces 81e and 82e of the sintered bodies 81 and 82.
  • the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed and integrated with each other in a state before being fixed to the housing 7.
  • the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed by being fitted with a fastening margin in the radial direction.
  • the large-diameter inner peripheral surface 81b of the first sintered body 81 and the small-diameter outer peripheral surface 83c on the upper side of the intermediate sleeve 83 are fitted with a margin.
  • the large-diameter inner peripheral surface 82b of the second sintered body 82 and the small-diameter outer peripheral surface 83d on the lower side of the intermediate sleeve 83 are fitted with a margin.
  • the regions on the shaft end side of the large-diameter inner peripheral surfaces 81b and 82b of the sintered bodies 81 and 82 and the small-diameter outer peripheral surfaces 83c and 83d of the intermediate sleeve 83 are slightly toward the shaft end side, respectively. It is formed in a tapered surface shape with a reduced diameter, and these are taper-fitted. Of course, these may be straight cylindrical surfaces.
  • the lower end surface 81f of the first sintered body 81 is in contact with the upper shoulder surface 83e of the intermediate sleeve 83
  • the upper end surface 82f of the second sintered body 82 is the lower shoulder surface of the intermediate sleeve 83. It is in contact with 83f.
  • the upper end surface 83g of the intermediate sleeve 83 is in contact with the shoulder surface 81c of the first sintered body 81
  • the lower end surface 83h of the intermediate sleeve 83 is in contact with the shoulder surface 82c of the second sintered body 82. Yes.
  • an axial gap may be provided on both sides.
  • an axial gap may be provided on both sides.
  • the bearing member 8 is fixed to the inner peripheral surface 7 a of the housing 7.
  • the outer peripheral surfaces 81e and 82e of the sintered bodies 81 and 82 are fixed to the inner peripheral surface 7a of the housing 7 by appropriate means such as press-fitting, gap bonding, and bonding with press-fitting.
  • the sintered bodies 81 and 82 and the intermediate sleeve 83 constituting the bearing member 8 are integrated with high dimensional accuracy, it is preferably fixed to the housing 7 by gap adhesion in order not to reduce the dimensional accuracy.
  • a radial clearance is provided between the large-diameter outer peripheral surface 83 b of the intermediate sleeve 83 and the inner peripheral surface 7 a of the housing 7.
  • a communication path F through which oil can flow is formed.
  • the radial distance between the large-diameter outer peripheral surface 83b of the intermediate sleeve 83 and the inner peripheral surface 7a of the housing 7 is smaller than the radial depth of the axial grooves 81e1 and 82e1 of the sintered bodies 81 and 82. .
  • the lid member 10 is formed in a disk shape from metal or resin.
  • the lid member 10 is fixed to the lower end of the inner peripheral surface 7 a of the housing 7. In the example of illustration, it fixes to the large diameter part 7a1 provided in the lower end of the internal peripheral surface 7a of the housing 7.
  • FIG. A thrust bearing surface C is provided on the upper end surface 10 a of the lid member 10.
  • a spiral dynamic pressure groove 10a1 as shown in FIG. 5 is formed on the thrust bearing surface C as a thrust dynamic pressure generating portion.
  • the illustrated dynamic pressure groove 10a1 is a pump-in type that pushes the lubricating oil filled in the thrust bearing gap into the inner diameter side.
  • the seal member 9 is formed in an annular shape with resin or metal and is fixed to the upper end portion of the inner peripheral surface 7a of the housing 7.
  • the lower end surface 9b of the seal member 9 is in contact with the upper end surface of the bearing member 8 (the upper end surface 81d of the upper sintered body 81).
  • An inner peripheral surface 9a of the seal member 9 is opposed to a tapered surface 2a2 provided on the outer peripheral surface of the shaft portion 2a in the radial direction, and a wedge-shaped seal space in which the radial dimension is gradually reduced downward therebetween. S is formed.
  • the seal space S When the shaft member 2 rotates, the seal space S functions as a capillary force seal and a centrifugal force seal, and prevents leakage of the lubricating oil filled in the housing 7 to the outside.
  • the wedge-shaped seal space S may be formed by using the outer peripheral surface of the shaft portion 2a as a cylindrical surface and the inner peripheral surface 9a of the seal member 9 as a tapered surface.
  • Lubricating oil as a lubricating fluid is injected into the fluid dynamic bearing device 1 composed of the above components.
  • the internal space of the fluid dynamic bearing device 1 including the internal pores of the sintered bodies 81 and 82 of the bearing member 8 is filled with the lubricating oil, and the oil level is always maintained within the range of the seal space S.
  • grease or magnetic fluid may be used as the lubricating fluid.
  • a radial bearing gap is formed between the radial bearing surfaces A1 and A2 of the sintered bodies 81 and 82 of the bearing member 8 and the outer peripheral surface (cylindrical surface 2a1) of the shaft portion 2a. Then, the pressure of the oil film in the radial bearing gap is increased by the dynamic pressure grooves 81a1 and 82a1 formed on the radial bearing surfaces A1 and A2, and the first radial bearing portion R1 and the second radial bearing portion R1 that support the shaft member 2 rotatably and in a non-contact manner.
  • a radial bearing portion R2 is configured.
  • a thrust bearing gap is formed between the upper end surface 2b1 of the flange portion 2b and the lower end surface 82d (thrust bearing surface B) of the second sintered body 82 of the bearing member 8, and the flange portion 2b
  • a thrust bearing gap is formed between the lower end surface 2b2 and the upper end surface 10a (thrust bearing surface C) of the lid member 10.
  • the pressure of the oil film of each thrust bearing gap is increased by the dynamic pressure groove 82d1 formed in the lower end surface 82d of the second sintered body 82 and the dynamic pressure groove 10a1 formed in the upper end surface 10a of the lid member 10.
  • the space on the outer diameter side of the flange portion 2 b of the shaft member 2 includes a communication path F formed between the outer peripheral surface of the bearing member 8 and the inner peripheral surface 7 a of the housing 7, and the bearing member 8. It communicates with the seal space S via a radial groove 81d2 in the upper end surface (the upper end surface 81d of the first sintered body 81).
  • the space on the outer diameter side of the flange portion 2b is always in a state close to atmospheric pressure, and generation of negative pressure in this space can be prevented.
  • One or both of the dynamic pressure grooves 81a1 and 82a1 formed on the inner peripheral surfaces 81a and 82a of the sintered bodies 81 and 82 are asymmetric in the axial direction, and the radial bearing gap is lubricated as the shaft member 2 rotates. A pumping force that pushes oil downward may be generated.
  • the lubricating oil circulates in a path of radial bearing clearance ⁇ thrust bearing clearance of the first thrust bearing portion T1 ⁇ communication path F ⁇ radial groove 81d2 ⁇ radial bearing clearance, the lubricating oil filled in the housing 7 is filled. Thus, local negative pressure can be reliably prevented from occurring.
  • the bearing member 8 forms first and second sintered bodies 81 and 82 and an intermediate sleeve 83, respectively, and sizing the sintered bodies 81 and 82 and these and the intermediate sleeve 83.
  • the internal pores of the sintered bodies 81 and 82 are impregnated with oil.
  • the first and second sintered bodies 81 and 82 are respectively a mixing step in which various metal powders are mixed to create a raw material powder, and the raw green powder is compression-molded to form a first green compact and a second green compact. It is formed through a compacting process for forming powder and a sintering process for sintering each compact.
  • a common raw material powder is created using the same mixing apparatus.
  • the sintering conditions heatating temperature, heating time, heating atmosphere, etc.
  • axial grooves 81e1 and 82e1 are formed on the outer peripheral surface of each compact, and an annular groove 81d1 and a radial groove 81d2 are formed on the end surface of the first compact. Is done. Accordingly, the axial grooves 81e1 and 82e1 are provided on the outer peripheral surfaces of the respective sintered bodies 81 and 82 before the sizing, and the annular grooves 81d1 and the radius are provided on the end surface of the first sintered body 81. A direction groove 81d2 is provided.
  • the intermediate sleeve 83 is formed by subjecting the melted material to plastic working such as forging or machining such as turning.
  • the assembly X is configured by combining the sintered bodies 81 and 82 and the intermediate sleeve 83 thus formed.
  • an intermediate sleeve 83 is disposed between the sintered bodies 81 and 82 in the axial direction, the large-diameter inner peripheral surface 81b of the first sintered body 81, the small-diameter outer peripheral surface 83c of the intermediate sleeve 83, and the first The large-diameter inner peripheral surface 82b of the second sintered body 82 and the small-diameter outer peripheral surface 83d of the intermediate sleeve 83 are fitted to each other to constitute the assembly X (see FIG. 7A).
  • the large-diameter inner peripheral surfaces 81b and 82b of the sintered bodies 81 and 82 and the small-diameter outer peripheral surfaces 83c and 83d of the intermediate sleeve 83 are fitted via a radial gap. That is, at this time, the sintered bodies 81 and 82 and the intermediate sleeve 83 are not fixed. At this time, the sintered bodies 81 and 82 and the intermediate sleeve 83 may be temporarily fixed by light press-fitting or the like, or may be completely fixed by press-fitting or adhesion.
  • the sintered bodies 81 and 82 are molded to a predetermined size, and at the same time, the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed and integrated.
  • the sizing and integration process will be described in detail with reference to FIGS. 7A to 7E.
  • the mold used in this process includes a die 21, a core rod 22, an upper punch 23 and a lower punch 24.
  • the inner diameter of the die 21 is slightly smaller than the outer diameter of the sintered bodies 81 and 82 before sizing and slightly larger than the outer diameter of the intermediate sleeve 83 (see FIG. 7A).
  • Formed on the outer peripheral surface of the core rod 22 are molding dies 22a and 22b having shapes corresponding to the dynamic pressure grooves 81a1 and 82a1 provided in the sintered bodies 81 and 82 (see FIG. 7B).
  • a molding die having a shape corresponding to the dynamic pressure groove 82b1 provided in the second sintered body 82 is provided (not shown).
  • the assembly X of the sintered bodies 81 and 82 and the intermediate sleeve 83 is disposed above the die.
  • the assembly X is arranged so that the first sintered body 81 is on the lower side and the second sintered body 82 is on the upper side. That is, the assembly X is arranged in a state where the bearing member 8 shown in FIG.
  • the core rod 22 is inserted into the inner periphery of the assembly X of the sintered bodies 81 and 82 and the intermediate sleeve 83.
  • the sintered bodies 81 and 82 and the intermediate sleeve 83 and the core rod 22 are fitted via a gap.
  • the end face of the second sintered body 82 is pressed downward by the upper punch 23, so that the assembly X is moved into the die 21. Push around (see FIG. 7C).
  • the sintered bodies 81 and 82 are press-fitted into the inner periphery of the die 21, and the intermediate sleeve 83 is fitted to the die 21 through a gap. Then, when the lower end surface of the assembly X (the lower end surface in the drawing of the second sintered body 82) is in contact with the upper end surface of the lower punch 24, the upper punch 23 is further lowered slightly, and the sintered bodies 81, 82. And the intermediate sleeve 83 is compressed in the axial direction. At this time, if necessary, the lower punch 24 may be slightly raised.
  • the sintered bodies 81 and 82 are pressed toward the inner diameter.
  • the small-diameter inner peripheral surfaces 81a and 82a of the sintered bodies 81 and 82 are pressed against the outer peripheral surface of the core rod 22, and the shapes of the molding dies 22a and 22b are formed on the small-diameter inner peripheral surfaces 81a and 82a of the sintered bodies 81 and 82.
  • the dynamic pressure grooves 81a1 and 82a1 are formed.
  • the large-diameter inner peripheral surfaces 81 b and 82 b of the sintered bodies 81 and 82 become the small-diameter outer peripheral surfaces 83 c and 83 d of the intermediate sleeve 83. They are pressed and come into close contact with each other. Thereby, the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed, and the bearing member 8 is formed.
  • the intermediate sleeve 83 since the small-diameter outer peripheral surfaces 83c and 83d of the intermediate sleeve 83 are pressed toward the inner diameter via the sintered bodies 81 and 82, the upper and lower ends of the inner peripheral surface 83a of the intermediate sleeve 83 can be slightly reduced in diameter. There is sex. Even in such a case, the inner diameter or the like of the intermediate sleeve 83 is set so that the inner peripheral surface 83 a of the intermediate sleeve 83 does not contact the outer peripheral surface of the core rod 22.
  • the sintered bodies 81 and 82 and the intermediate sleeve 83 are pressed in the axial direction. At this time, since the internal pores of the sintered bodies 81 and 82 are crushed, the amount of axial deformation (compression) is relatively large.
  • the intermediate sleeve 83 is formed of a material having a smaller load deformation amount in the axial direction than the sintered bodies 81 and 82, the deformation amount in the axial direction is smaller than that of the sintered bodies 81 and 82. In particular, by forming the intermediate sleeve 83 from a melted material, it hardly deforms due to axial compression.
  • the deformation amount of the entire bearing member 8 due to sizing is suppressed. Therefore, the axial total length L of the bearing member 8 (see FIG. 3), the axial distance between the radial bearing surfaces A1 and A2, specifically, the maximum surface pressure generating portion (in the illustrated example) of each radial bearing surface A1 and A2.
  • the variation in the product in the axial interval P of the annular hill portion provided at the center in the axial direction is suppressed.
  • the intermediate sleeve 83 is hardly compressed, a compression force is easily applied to the sintered bodies 81 and 82. Therefore, the radial bearing surfaces A1 and A2 of the sintered bodies 81 and 82, and the dynamic pressure grooves 81a1 and 81a1 are further provided. 82a1 can be accurately molded.
  • the thrust bearing surface B and further the dynamic pressure groove 82d1 are formed on the lower end surface 82d of the sintered body 82 by the above sizing process, so that these can be formed with high accuracy.
  • the intermediate sleeve 83 since the intermediate sleeve 83 is not compressed, it becomes easy to apply the same pressing force to the sintered bodies 81 and 82, so that the sintered bodies 81 and 82 are finished with the same dimensional accuracy, and in particular, the radial bearing surface. A difference in inner diameter between A1 and A2 is suppressed.
  • the bearing member 8, the core rod 22, and the upper and lower punches 23, 24 are raised together and taken out from the inner periphery of the die 21.
  • FIG. 7E after the core rod 22 and the upper punch 23 are raised and the core rod 22 is pulled out from the inner periphery of the bearing member 8, the bearing member 8 is discharged from the mold.
  • the bearing member 8 thus assembled is transferred to the oil impregnation process. Specifically, after the bearing member 8 is immersed in oil under a reduced pressure environment, the internal pores of the sintered bodies 81 and 82 are impregnated with oil by returning to normal pressure.
  • the fluid dynamic bearing device 1 shown in FIG. 2 is completed by assembling the bearing member 8, the shaft member 2, the housing 7, and the seal member 9 and injecting oil into the housing 7.
  • the present invention is not limited to the above embodiment.
  • part which has a function similar to said embodiment attaches
  • the embodiment shown in FIG. 8 is different from the above-described embodiment in the connection state between the sintered bodies 81 and 82 and the intermediate sleeve 83.
  • the inner peripheral surfaces and outer peripheral surfaces of the sintered bodies 81 and 82 and the intermediate sleeve 83 have a substantially straight cylindrical shape.
  • Grooves 83g1 and 83h1 are formed in both end faces 83g and 83h of the intermediate sleeve 83.
  • a plurality of (four in the illustrated example) grooves 83g1 and 83h1 are arranged at equal intervals in the circumferential direction on both end faces 83g and 83h of the intermediate sleeve 83.
  • Each groove 83g1, 83h1 has a gradually narrowing circumferential width as it goes to the outer diameter side.
  • FIGS. 9A and 9C in the both end faces 83g and 83h of the intermediate sleeve 83, the formation regions of the grooves 83g1 and 83h1 are dotted.
  • the end surfaces 81f and 82f of the sintered bodies 81 and 82 are provided with convex portions 81f1 and 82f1 that enter the grooves 83g1 and 83h1 of the intermediate sleeve 83, respectively.
  • the grooves 83g1 and 83h1 of the intermediate sleeve 83 and the projections 81f1 and 82f1 of the sintered bodies 81 and 82 are in close contact with each other in the direction perpendicular to the axis, whereby the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed.
  • the convex portions 81f1 and 82f1 of the sintered bodies 81 and 82 are in close contact with the side surfaces and the bottom surface on both sides in the circumferential direction of the grooves 83g1 and 83h1 of the intermediate sleeve 83. Is engaged.
  • the shapes of the grooves 83g1 and 83h1 are not limited to the above, and for example, a circumferential annular groove, a radial groove, or both of them may be provided.
  • the above-described bearing member 8 can be manufactured by the following procedure. First, sintered bodies 81 and 82 having flat end surfaces not provided with the convex portions 81f1 and 82f1 are formed.
  • the intermediate sleeve 83 is formed in a finished product shape shown in FIGS.
  • the intermediate sleeve 83 is formed of, for example, a molten material so that the amount of load deformation in the axial direction is smaller than that of each of the sintered bodies 81 and 82.
  • the intermediate sleeve 83 and the sintered bodies 81 and 82 are combined to form an assembly X, and the assembly X is sized in the same procedure as shown in FIG.
  • convex portions 81f1 and 82f1 that enter the grooves 83g1 and 83h1 of the intermediate sleeve 83 are formed on the end surfaces 81f and 82f of the sintered bodies 81 and 82, and the sintered bodies 81 and 82 and the intermediate sleeve 83 are fixed.
  • the assembly X is inserted into the inner periphery of the die 21 through a radial gap, and in this state, the assembly X is compressed from both sides in the axial direction to expand the sintered bodies 81 and 82 in the radial direction. You may make it press on the die
  • the present invention is not limited to this.
  • three or more sintered bodies or two or more intermediate sleeves are provided. Or you may.
  • the radial dynamic pressure generating portions provided on the radial bearing surfaces A1 and A2 of the bearing member 8 are not limited to the herringbone-shaped dynamic pressure grooves 81a1 and 82a1, but include, for example, spiral-shaped dynamic pressure grooves and axial directions. Alternatively, a step-shaped dynamic pressure groove extending in the direction may be used.
  • the thrust dynamic pressure generating portions provided on the thrust bearing surface B of the bearing member 8 and the thrust bearing surface C of the lid member 10 are not limited to the spiral-shaped dynamic pressure grooves 82d1 and 10a1, but have a herringbone shape, a step shape, or the like. Other shapes of dynamic pressure grooves may be used.
  • the flange portion 2b of the shaft member 2 is omitted, a spherical convex portion is provided at the lower end of the shaft portion 2a, and the convex bearing and the upper end surface 10a of the lid member 10 are brought into contact with each other to thereby provide a thrust bearing portion (pivot bearing).
  • a thrust bearing portion pivot bearing
  • the dynamic pressure groove 82d1 provided on the end surface of the bearing member 8 and the dynamic pressure groove 10a1 provided on the upper end surface 10a of the lid member 10 are omitted.
  • a dynamic pressure generating portion may be formed on the outer peripheral surface (cylindrical surface 2a1) of the shaft member 2 facing the surface through a bearing gap, the upper end surface 2b1 and the lower end surface 2b2 of the flange portion 2b.
  • both the inner peripheral surface of the bearing member 8 and the outer peripheral surface of the shaft member 2 may be cylindrical surfaces to constitute a perfect circle bearing. In this case, a dynamic pressure action is generated in the lubricating fluid in the radial bearing gap due to the swing of the shaft member 2.
  • the shaft rotation type fluid dynamic pressure bearing device in which the shaft member 2 rotates is shown.
  • the present invention is not limited thereto, and the shaft member 2 is fixed, and the shaft fixed type in which the bearing member 8 side rotates.
  • the present invention can also be applied to a fluid dynamic bearing device or a fluid dynamic bearing device in which both the shaft member 2 and the bearing member 8 rotate.
  • fluid dynamic pressure bearing device described above can be applied not only to a fan motor but also to an HDD spindle motor, a polygon scanner motor of a laser beam printer, a color wheel of a projector, and the like.
  • a fluid dynamic bearing device 101 shown in FIG. 10 has a bearing member 103 according to an embodiment of the present invention, a shaft member 102 inserted in the inner periphery of the bearing member 103, and adhesion or press-fit adhesion (adhesion in a press-fit state). And a cylindrical housing 104 in which the bearing member 103 is fixed to the inner periphery by appropriate means.
  • the shaft member 102 is supported so as to be relatively rotatable in the radial direction by radial bearing portions R1 and R2 formed at two positions spaced apart in the axial direction.
  • the bearing member 103 includes a plurality of cylindrical bodies (in the present embodiment, a first cylindrical body 131 and a second cylindrical body 132) that are arranged in a row in the axial direction.
  • the internal space of the housing 104 is filled with lubricating oil as a lubricating fluid.
  • the description will proceed with the side on which the first cylindrical body 131 is disposed as the upper side and the side on which the second cylindrical body 132 is disposed on the lower side, but the fluid dynamic pressure bearing device 101 (bearing member 103).
  • the use mode there is no limitation on the use mode.
  • the shaft member 102 is formed of, for example, a metal material such as stainless steel, and a portion of the outer peripheral surface 102a that faces the inner peripheral surface of the bearing member 103 is formed as a smooth cylindrical surface without unevenness.
  • the first cylindrical body 131 and the second cylindrical body 132 constituting the bearing member 103 are both made of a sintered metal porous body mainly composed of copper or iron and formed in a substantially cylindrical shape.
  • the yield point of the first cylindrical body 131 is relatively small, and the yield point of the second cylindrical body 132 is relatively large.
  • the second cylindrical body 132 is formed of a sintered metal having a higher strength than the first cylindrical body 131.
  • the sintered metal cylinders 131 and 132 having different yield points for example, make the composition of the raw material powders different from each other, make the molding pressures different when obtaining the green compact of the raw material powder, or It can be obtained by adopting means such as different sintering conditions.
  • a radial bearing surface A1 is provided.
  • a dynamic pressure generating portion (radial dynamic pressure generating portion) 108 for generating a dynamic pressure action on the lubricating oil in the radial bearing gap of the radial bearing portion R1 is formed on the radial bearing surface A1.
  • the illustrated dynamic pressure generator 108 includes a plurality of upper dynamic pressure grooves 108a1 inclined with respect to the axial direction, a plurality of lower dynamic pressure grooves 108a2 inclined in a direction opposite to the upper dynamic pressure grooves 108a1, and a dynamic pressure
  • the grooves 108a1 and 108a2 are divided into convex hills, and the dynamic pressure grooves 108a1 and 108a2 are arranged in a herringbone shape as a whole.
  • the hill portion includes an inclined hill portion 108b provided between the dynamic pressure grooves adjacent to each other in the circumferential direction, and an annular hill portion 108c that is provided between the upper and lower dynamic pressure grooves 108a1 and 108a2 and has substantially the same diameter as the inclined hill portion 108b. Consists of.
  • the inner peripheral surface 132a of the second cylindrical body 132 is partitioned into a relatively small-diameter small-diameter internal peripheral surface 132a1 and a relatively large-diameter large-diameter internal peripheral surface 132a2.
  • the radial bearing surface A2 is formed with a dynamic pressure generating portion (radial dynamic pressure generating portion) 8 for generating a dynamic pressure action on the lubricating oil in the radial bearing gap of the radial bearing portion R2. ing.
  • the dynamic pressure generation unit 108 has the same configuration as the dynamic pressure generation unit 108 provided on the inner peripheral surface 131a (radial bearing surface A1) of the first cylindrical body 131.
  • the large-diameter inner peripheral surface 132a2 is disposed between the two radial bearing surfaces A1 and A2 to form a middle escape portion B.
  • the shape of the dynamic pressure generator 108 provided on both the radial bearing surfaces A1 and A2 is merely an example, and it is of course possible to adopt other known dynamic pressure generators 108.
  • the first cylindrical body 131 and the second cylindrical body 132 constituting the bearing member 103 are coupled by a concave and convex fitting structure 107 formed between the cylindrical bodies 131 and 132.
  • the concave-convex fitting structure 107 is an upper end surface of the second cylindrical body 132 among two surfaces (here, the lower end surface 131b of the first cylindrical body 131 and the upper end surface 132c of the second cylindrical body 132) facing each other in the axial direction.
  • a convex raised portion 106 (convex portion) provided on the lower end surface 131b of the first cylindrical body 131 is brought into close contact with the inner wall surface of the concave portion 105 provided in 132c.
  • the concave portion 105 and the convex raised portion 106 in close contact with the concave portion 105 each have an annular shape.
  • the annular region excluding the portion where the raised portion 106 is formed in the lower end surface 131b of the first cylindrical body 131 and the annular region excluding the portion where the recess 105 is formed in the upper end surface 132c of the second cylindrical body 132 are These are all formed on a flat surface extending in a direction orthogonal to the axis (axial direction), and the two flat surfaces are in close contact with each other.
  • the radial fitting surfaces A1 and A2 having the dynamic pressure generating portion 108 are provided on the inner peripheral surfaces of the two cylindrical bodies 131 and 132, respectively, and the concave-convex fitting structure formed between the two cylindrical bodies 131 and 132.
  • the bearing member 103 formed by coupling the two cylindrical bodies 131 and 132 by the 107 is a first cylindrical body 131 and a second cylindrical body 132 that are arranged in a line in the axial direction (strictly speaking, each of the first and second cylindrical bodies 131 and 132 has the above-described configuration by sizing.
  • the first cylindrical material 131 ′ and the second cylindrical material 132 ′) finished into the first and second cylindrical bodies 131 and 132 are obtained by sizing.
  • the sizing process will be described in detail with reference to FIGS. 12A to 12C.
  • the sizing process is performed using a sizing die 110 including a core rod 111, a cylindrical die 112, and a pair of upper and lower punches 113 and 114 arranged coaxially.
  • a sizing die 110 including a core rod 111, a cylindrical die 112, and a pair of upper and lower punches 113 and 114 arranged coaxially.
  • an uneven mold corresponding to the shape of the dynamic pressure generating portions 108 and 108 (having the radial bearing surfaces A1 and A2) is vertically spaced on the outer peripheral surface of the core rod 111. It is provided in two places.
  • a first cylindrical material 131 ′ shown in FIG. 12A is finished to a first cylindrical body 131 having the above-described configuration by sizing, and a radial bearing surface A1 (dynamic pressure generating portion 108) is provided on the inner peripheral surface thereof. Absent. Further, in the first cylindrical material 131 ′, the lower end surface 131 b ′ that becomes the lower end surface 131 b of the first cylindrical body 131 after sizing is formed as a flat surface in the direction orthogonal to the axis.
  • the second cylindrical material 132 ′ is finished to the second cylindrical body 132 having the above-described configuration by sizing, and the inner peripheral surface thereof is a relatively small-diameter small-diameter inner peripheral surface and a relatively large-diameter large-diameter inside. Although divided into a peripheral surface, the radial bearing surface A2 (dynamic pressure generating portion 108) is not provided on the small-diameter inner peripheral surface. However, of the second cylindrical material 132 ′, an annular recess 105 is provided on the upper end surface 132 c ′ which becomes the upper end surface 132 c of the second cylindrical body 132 after sizing.
  • the first and second cylindrical materials 131 ′ and 132 ′ having the above configuration are both sintered metal porous bodies obtained by sintering a green compact of raw material powder.
  • the first cylindrical material 131 ′ of this embodiment has a yield point smaller than that of the second cylindrical material 132 ′.
  • both cylindrical materials 131 ′ and 132 ′ are arranged on the upper end surface 112 a of the die 112 so as to be connected in the axial direction (superposed vertically). More specifically, the second cylindrical material 132 ′ is placed on the upper end surface 112a of the die 112 in an upright posture with the upper end surface 132c ′ provided with the recess 105 on the upper side, and the lower end surface 131b ′ is placed on the lower side. The first cylindrical material 131 ′ is placed on the second cylindrical material 132 ′ in the standing posture. Then, the core rod 111 is inserted into the inner circumference of both cylindrical materials 131 ′ and 132 ′.
  • both cylindrical materials 131 ′ and 132 ′ are press-fitted into the inner periphery of the die 112, and the outer peripheral surfaces of both cylindrical materials 131 ′ and 132 ′. Is restrained.
  • FIG. 12C when the core rod 111 and the upper punch 113 are further lowered and both the cylindrical materials 131 ′ and 132 ′ are compressed in the axial direction by the upper punch 113 and the lower punch 114, both the cylindrical materials 131 ′ and 132 ′.
  • both cylindrical materials 131 ′ and 132 ′ are pressed against the inner peripheral surface 112 b of the die 112 and the outer peripheral surface 111 a of the core rod 111, respectively.
  • the outer peripheral surface and inner peripheral surface of both cylindrical materials 131 ′ and 132 ′ are deformed following the inner peripheral surface 112b of the die 112 and the outer peripheral surface 111a of the core rod 111, and the inner peripheral surface of the first cylindrical material 131 ′.
  • the radial bearing surfaces A1 and A2 having the dynamic pressure generating portion 108 are formed on the inner peripheral surface (small inner peripheral surface) of the second cylindrical material 132 ′.
  • the lower end surface 131b ′ of the first cylindrical material 131 ′ protrudes from the portion facing the concave portion 105 provided on the upper end surface 132c ′ of the second cylindrical material 132 ′.
  • a raised portion 106 is formed, and the raised portion 106 is in close contact with the inner wall surface of the recess 105.
  • the concave-convex fitting structure 107 is formed between the cylindrical materials 131 ′ and 132 ′.
  • the core rod 111 and the upper and lower punches 113 and 114 are raised integrally to form both cylindrical materials 131 ′ and 132 ′.
  • the upper punch 113 and the core rod 111 are further raised.
  • the radial bearing surface A1 having the dynamic pressure generating portion 108 is formed on the inner peripheral surface 131a of the first cylindrical body 131, and the inner peripheral surface 132a (small diameter inner peripheral surface 132a1) of the second cylindrical body 132 is moved.
  • a bearing member 103 is obtained in which a radial bearing surface A2 having a pressure generating portion 108 is formed, and the two cylindrical bodies 131 and 132 are coupled by the concave-convex fitting structure 107.
  • the radial bearing surfaces A1 and A2 that are spaced apart at two locations on the inner periphery of the bearing member 103, and these A radial bearing gap is formed between the shaft member 102 and the outer peripheral surface 102a facing each other.
  • the pressure of the oil film formed in the radial bearing gaps is increased by the dynamic pressure action of the dynamic pressure generating portions 108 and 108.
  • the shaft member 102 is moved in the radial direction.
  • Radial bearing portions R1 and R2 that are supported in a non-contact manner so as to be relatively rotatable are formed at two locations separated in the axial direction.
  • a cylindrical lubricating oil reservoir is formed between the two radial bearing gaps by providing the cylindrical surface escape portion B on the inner periphery of the bearing member 103 (second cylindrical body 132). Therefore, it is possible to prevent as much as possible an oil film breakage between the radial bearing gaps, that is, a reduction in bearing performance of the radial bearing portions R1 and R2.
  • the fluid dynamic bearing device 101 described above includes, for example, (1) a spindle motor for a disk device, (2) a polygon scanner motor for a laser beam printer, or (3) a fan for a PC. Used as a bearing device for a motor such as a motor.
  • a disk hub having a disk mounting surface is provided integrally or separately on the shaft member 102
  • a polygon mirror is provided integrally or separately on the shaft member 102.
  • a fan having blades on the shaft member 102 is provided integrally or separately.
  • any one of the lower end surface 131b of the first cylindrical body 131 and the upper end surface 132c of the second cylindrical body 132 facing each other in the axial direction [
  • the concave portion 105 provided only on the upper end surface 132c (132c ′)]
  • the convex raised portion 106 generated on the other end surface (here, the lower end surface 131b (131b ′)] is brought into close contact with the sizing.
  • the first and second cylindrical bodies 131 and 132 that are adjacent in the axial direction are joined together by the concave-convex fitting structure 107 formed in (1).
  • a convex raised portion 106 that is in close contact with the concave portion 105 is formed on the lower end surface 131b ′ along with sizing.
  • the shape of the lower end surface 131b ′ of the first cylindrical material 131 ′ before the sizing can be arbitrarily set. Therefore, before the sizing, the entire lower end surface 131b ′ of the first cylindrical material 131 ′ is flat with the direction orthogonal to the axis, that is, the upper end surface 132c ′ of the second cylindrical material 132 ′ (as described above).
  • the yield of the second cylindrical body 132 (second cylindrical material 132 ′) provided with the recess 105 is provided. Since the point is relatively large, it is possible to prevent as much as possible a situation in which the concave portion 105 of the second cylindrical body 132 is deformed with sizing and the cylindrical bodies 131 and 132 are not properly coupled. Can do.
  • the bearing member 103 according to an embodiment of the present invention and the fluid dynamic pressure bearing device 101 including the bearing member 103 have been described above, but various changes have been made to the bearing member 103 without departing from the gist of the present invention. Can be applied.
  • the concave portion 105 for forming the concave / convex fitting structure 107 has two end surfaces (the lower end surface 131b of the first cylindrical body 131b and the second cylindrical body 132 of the first cylindrical body 131) facing each other in the axial direction.
  • the upper end surface 132c is configured by an annular groove provided at a substantially central portion in the radial direction.
  • FIG. 13A specifically shows an example of this, and the concave portions 105 each formed of an annular groove are provided at two locations spaced in the radial direction of the upper end surface 132 c of the second cylindrical body 132.
  • the convex raised portions 106 that are in close contact with the concave portion 105 are formed at two locations that are spaced apart from each other in the radial direction of the lower end surface 131 b of the first cylindrical body 131.
  • the concave portion 105 for forming the concave / convex fitting structure 107 can be constituted by a groove having a circumferential end as shown in FIGS. 13B and 13C, for example, in addition to the annular groove.
  • FIG. 13B is an example of the case where the concave portion 105 is configured by a radial groove whose groove width gradually decreases toward the outer diameter side
  • FIG. 13C is the case where the concave portion 105 is configured by a radial groove having a constant groove width.
  • the shape of the recess 105 is not limited to that described above, and the recess 105 may be configured by, for example, a spiral groove or dimple (a recess having a substantially semicircular cross section) (not shown).
  • the concave-convex fitting structure 107 includes a first and a first arranged in an axial direction with respect to the concave portion 105 provided on the lower end surface 131b of the first cylindrical body 131 (the lower end surface 131b ′ of the first cylindrical material 131 ′).
  • the upper end surface 132c of the second cylindrical body 132 (the upper end surface 132c ′ of the second cylindrical material 132 ′). It is also possible to form the ridges 106 by bringing them into close contact with each other.
  • the middle escape portion B may be configured not by the second cylindrical body 132 but by the inner peripheral surface of the first cylindrical body 131, or by both the inner peripheral surfaces of the first and second cylindrical bodies 131 and 132. It may be configured.
  • the bearing member 103 is connected in the axial direction as shown in FIG. 14, in addition to the two cylindrical bodies (first and second cylindrical bodies 131 and 132) connected in the axial direction. It is also possible to configure by connecting three cylindrical bodies arranged in the same manner. More specifically, the bearing member 103 shown in FIG. 14 is disposed at one end (upper end) in the axial direction, and includes a first cylindrical body 131 made of sintered metal having a radial bearing surface A1 on the inner peripheral surface 131a, and an axial direction. And a second cylindrical body 132 made of sintered metal having a radial bearing surface A2 on the inner peripheral surface 132a, and a third cylindrical body 133 disposed therebetween.
  • a middle escape portion B is formed by the inner peripheral surface 133 a of the third cylindrical body 133.
  • the first cylindrical body 131 and the third cylindrical body 133 that are adjacent in the axial direction are joined together by an uneven fitting structure 107 formed therebetween.
  • the third cylindrical body 133 and the second cylindrical body 132 that are adjacent in the axial direction are coupled together by the concave-convex fitting structure 107 formed therebetween.
  • the convex raised portion 106 formed on the lower end surface 131 b of the first cylindrical body 131 is formed with respect to the concave portion 105 formed of an annular groove provided on the upper end surface 133 b of the third cylindrical body 133.
  • the concave-convex fitting structure 107 that joins the first and third cylindrical bodies 131 and 133 is formed.
  • the convex ridge 106 formed on the upper end surface 132c of the second cylindrical body 132 is brought into close contact with the concave portion 105 formed of an annular groove provided on the lower end surface 133c of the third cylindrical body 133, whereby the first A concave-convex fitting structure 107 that couples the second and third cylindrical bodies 132 and 133 is formed.
  • either one or both of these two concave-convex fitting structures 107 can be formed by a concave portion 105 as shown in FIGS. 13A to 13C and a convex raised portion 106 in close contact therewith.
  • the bearing member 103 shown in FIG. 14 is also obtained by sizing the three cylindrical bodies 131 to 133 arranged in the axial direction in the same manner as the bearing member 103 shown in FIG. . That is, both radial bearing surfaces A1 and A2 are formed by the above sizing. With this sizing, convex raised portions 106 are formed on the lower end surface 131b of the first cylindrical body 131 and the upper end surface 132b of the second cylindrical body 132, and these raised portions 106 are respectively connected to the third cylindrical body 133.
  • the concave-convex fitting structure 107 that couples the cylindrical bodies adjacent in the axial direction is formed.
  • the concave portion 105 is deformed with sizing and the possibility that the predetermined concave-convex fitting structure 107 cannot be obtained is reduced. Therefore, the third cylindrical body 133 having the concave portion 105 is replaced with the first cylindrical body 131 and the first cylindrical body 133. It is made of a material having a yield point larger than that of the two cylinders 132.
  • the third cylindrical body 133 may be formed of a sintered metal porous body in the same manner as the first and second cylindrical bodies 131 and 132, but here, the third cylindrical body 133 is made of a molten material such as stainless steel or brass. A cylindrical body 133 is formed.
  • the amount of lubricating oil to be filled in the internal space of the fluid dynamic bearing device 101 can be reduced as compared with the case where the third cylindrical body 133 is formed of sintered metal. This is advantageous in reducing the cost of the apparatus 101.
  • the bearing member 103 described above can be used not only for radial loads but also for supporting thrust loads.
  • a thrust bearing surface is provided on one or both of the upper end surface 131c of the first cylindrical body 131 and the lower end surface 132b of the second cylindrical body 132 in accordance with the shape of the shaft to be supported (the shaft member 102). be able to.
  • the thrust bearing surface can be molded at the same time as sizing a plurality of cylindrical bodies arranged in a row in the axial direction, and the thrust bearing surface has a dynamic pressure such as a dynamic pressure groove.
  • a generator thrust dynamic pressure generator
  • the thrust dynamic pressure generating portion can be molded simultaneously with sizing the plurality of cylindrical bodies.
  • the radial dynamic pressure generating portion 108 is molded on the inner peripheral surface of the bearing member 103. 108 may be provided on the outer peripheral surface 102 a of the shaft member 102 facing the inner peripheral surface of the bearing member 103.
  • the present invention is not limited to the case where the bearing member 103 is constituted by two or three cylindrical bodies arranged in a row in the axial direction, but also four or more pieces arranged in a row in the axial direction.
  • the present invention is also applicable when the bearing member 103 is formed of a cylindrical body.
  • the embodiment of the first invention of the present application and the embodiment of the second invention of the present application described above can be appropriately combined. That is, the configuration shown in the embodiment of the first invention of the present application can be applied to the embodiment of the second invention of the present application, and the configuration shown in the embodiment of the second invention of the present application is applied to the embodiment of the first invention of the present application. It can also be applied to.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Sliding-Contact Bearings (AREA)

Abstract

L'invention concerne un élément palier (8), lequel élément comprend : une pluralité de corps frittés (81, 82) comportant des surfaces de portée (A1, A2) sur leurs surfaces périphériques internes ; et un manchon intermédiaire (83) qui est disposé entre la pluralité de corps frittés (81, 82) dans une direction axiale. La pluralité de corps frittés (81, 82) sont dimensionnés selon un état dans lequel la pluralité de corps frittés (81, 82) et le manchon intermédiaire (83) sont reliés entre eux. La déformation dans la direction axiale sous une charge du manchon intermédiaire (83) est inférieure à la déformation dans la direction axiale sous une charge de chacun des corps frittés (81, 82).
PCT/JP2016/056947 2015-03-23 2016-03-07 Élément palier, dispositif de palier de pression dynamique à fluide le comportant, et procédé de fabrication d'élément palier WO2016152474A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP2015-059691 2015-03-23
JP2015059691A JP2016180427A (ja) 2015-03-23 2015-03-23 流体動圧軸受装置用軸受部材及びその製造方法
JP2015-062504 2015-03-25
JP2015062504A JP2016180496A (ja) 2015-03-25 2015-03-25 軸受部材及びその製造方法

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WO2016152474A1 true WO2016152474A1 (fr) 2016-09-29

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018079670A1 (fr) * 2016-10-26 2018-05-03 株式会社ダイヤメット Palier en métal fritté imprégné d'huile

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001041244A (ja) * 1999-07-27 2001-02-13 Hitachi Powdered Metals Co Ltd 軸受の製造方法
JP2007327546A (ja) * 2006-06-07 2007-12-20 Ntn Corp 流体軸受装置の製造方法
JP2007327544A (ja) * 2006-06-07 2007-12-20 Ntn Corp 動圧軸受装置
JP2008064123A (ja) * 2006-09-04 2008-03-21 Ntn Corp 流体軸受装置およびその製造方法
JP2008261396A (ja) * 2007-04-11 2008-10-30 Ntn Corp 流体軸受装置およびその製造方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001041244A (ja) * 1999-07-27 2001-02-13 Hitachi Powdered Metals Co Ltd 軸受の製造方法
JP2007327546A (ja) * 2006-06-07 2007-12-20 Ntn Corp 流体軸受装置の製造方法
JP2007327544A (ja) * 2006-06-07 2007-12-20 Ntn Corp 動圧軸受装置
JP2008064123A (ja) * 2006-09-04 2008-03-21 Ntn Corp 流体軸受装置およびその製造方法
JP2008261396A (ja) * 2007-04-11 2008-10-30 Ntn Corp 流体軸受装置およびその製造方法

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018079670A1 (fr) * 2016-10-26 2018-05-03 株式会社ダイヤメット Palier en métal fritté imprégné d'huile
JPWO2018079670A1 (ja) * 2016-10-26 2019-09-19 株式会社ダイヤメット 焼結含油軸受
US10865828B2 (en) 2016-10-26 2020-12-15 Diamet Corporation Oil-impregnated sintered bearing

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