WO2024057868A1 - Palier hydrodynamique, dispositif de palier hydrodynamique et moteur - Google Patents

Palier hydrodynamique, dispositif de palier hydrodynamique et moteur Download PDF

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Publication number
WO2024057868A1
WO2024057868A1 PCT/JP2023/030575 JP2023030575W WO2024057868A1 WO 2024057868 A1 WO2024057868 A1 WO 2024057868A1 JP 2023030575 W JP2023030575 W JP 2023030575W WO 2024057868 A1 WO2024057868 A1 WO 2024057868A1
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WIPO (PCT)
Prior art keywords
dynamic pressure
sintered body
bearing
groove
hill
Prior art date
Application number
PCT/JP2023/030575
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English (en)
Japanese (ja)
Inventor
慎治 小松原
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Ntn株式会社
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Publication of WO2024057868A1 publication Critical patent/WO2024057868A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
    • B22F3/12—Both compacting and sintering
    • 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
    • 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
    • F16C17/04—Sliding-contact bearings for exclusively rotary movement for axial load only
    • F16C17/08—Sliding-contact bearings for exclusively rotary movement for axial load only for supporting the end face of a shaft or other member, e.g. footstep bearings
    • 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
    • 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
    • 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/08—Structural association with bearings

Definitions

  • the present invention relates to a hydrodynamic bearing.
  • a dynamic pressure bearing is a cylindrical bearing member with dynamic pressure grooves formed on its inner peripheral surface.
  • the hydrodynamic bearing and the shaft member inserted into its inner circumference rotate relative to each other, the pressure of the fluid film generated in the radial bearing gap between the outer circumference of the shaft member and the inner circumference of the hydrodynamic bearing is reduced by the hydrodynamic groove.
  • This pressure allows the shaft member to be relatively rotatably supported in a non-contact manner. Due to its excellent rotational accuracy and quietness, fluid dynamic bearing devices having the above-mentioned hydrodynamic bearings and shaft members are used in spindle motors of HDD disk drives, polygon scanner motors of laser beam printers, and electronic devices. It is suitably used to support the rotating shaft of a cooling fan motor, etc.
  • dynamic pressure groove sizing As a method for forming dynamic pressure grooves on the inner circumferential surface of a hydrodynamic bearing, so-called dynamic pressure groove sizing is known, in which dynamic pressure grooves are molded on the inner circumferential surface of a cylindrical sintered body.
  • a sizing pin is inserted into the inner circumference of the sintered compact, and the sintered compact is press-fitted into the inner circumference of the die while being compressed in the axial direction by an upper punch and a lower punch.
  • the inner peripheral surface of the body is pressed against a mold formed on the outer peripheral surface of the sizing pin. As a result, the shape of the mold is transferred to the inner circumferential surface of the sintered body, and dynamic pressure grooves are formed (see, for example, Patent Document 1).
  • FIG. 14 and 15 are diagrams showing the shapes (profiles) of dynamic pressure grooves of dynamic pressure bearings formed under the same conditions.
  • the maximum diameter difference between each dynamic pressure groove and the adjacent hill portion on one side in the circumferential direction is defined as the depth of each dynamic pressure groove (hereinafter also referred to as "groove depth") Hf1 to Hf6.
  • the groove depths Hf1 to Hf6 have small variations (the difference between the maximum groove depth and the minimum groove depth is about 0.3 ⁇ m), and as shown in Fig. 15, the groove depths Hf1 to Hf6 are small.
  • an object of the present invention is to stably supply a hydrodynamic bearing with high bearing rigidity.
  • the inner peripheral surface of the sintered body 28 is pressed against a mold 35 formed on the outer peripheral surface of the core rod 31, and the sintering process is performed.
  • the material (meat) of the body 28 is introduced into the recess 35a of the mold 35.
  • the ratio h'/Hf' between the circumferential width h' [mm] and the depth Hf' [ ⁇ m] of the recess 35a is too small, that is, the circumferential width h' of the recess 35a is too small, If the depth Hf' of the recess 35a is too deep, it becomes difficult for the material of the sintered body 28 to enter the recess 35a. Therefore, it becomes difficult to fill the entire area of the recess 35a with the material of the sintered body 28, and the molding accuracy of the hill portion and, ultimately, the molding accuracy of the dynamic pressure groove decreases.
  • the ratio (flatness) h'/Hf' between the circumferential width h' [mm] and the depth Hf' [ ⁇ m] of the concave portion of the mold is made larger than 0.1. This makes it easier for the material of the sintered body to penetrate into the corners of the recesses, so we can stably supply products with variations in the height of multiple hills, that is, the depth of multiple dynamic pressure grooves, of 1 ⁇ m or less. can do.
  • the shape of the concave part of the core rod is transferred to the hill part between the dynamic pressure grooves formed in the sintered body, so the circumferential width h [mm] and the height (the circumferential direction of the concave part) of each hill part are
  • the ratio (flatness) h/Hf to the depth (depth) Hf [ ⁇ m] of the dynamic pressure groove adjacent to one side (flatness) becomes larger than 0.1.
  • the ratio h'/Hf' between the circumferential width h' [mm] and the depth Hf' [ ⁇ m] of the concave part of the mold that is, the circumferential width h [mm] and the height of the hill part of the sintered body. It is preferable that the ratio h/Hf to the height Hf [ ⁇ m] be smaller than a predetermined value, and specifically, it is preferable to be smaller than 0.65.
  • the present invention provides a hydrodynamic bearing including a sintered body in which a hydrodynamic pressure generating part is molded on the inner peripheral surface.
  • the dynamic pressure generating portion has a plurality of dynamic pressure grooves extending in a direction inclined with respect to the circumferential direction, and a plurality of inclined hill portions provided between the plurality of dynamic pressure grooves in the circumferential direction,
  • the ratio h/Hf of the circumferential width h [mm] of each inclined hill portion to the depth Hf [ ⁇ m] of the dynamic pressure groove adjacent to one circumferential side of the inclined hill portion is 0.1 ⁇ h /Hf ⁇ 0.65, It can be characterized as a hydrodynamic bearing in which the variation in depth Hf of the plurality of hydrodynamic grooves is 1 ⁇ m or less.
  • the density of the sintered body is low, when forming dynamic pressure grooves by pressing the sintered body from the outside diameter side, it will be difficult to apply pressure to the inner peripheral surface of the sintered body, so the dynamic pressure grooves will not be formed. It becomes difficult to mold with high precision. Therefore, it is preferable to set the density of the sintered body to be high. Specifically, the density ratio of the sintered body (density of the sintered body/density assuming that the sintered body has no pores) is set to a high value. It is preferably 80% or more.
  • the density of the sintered body is too high, the pores formed inside the sintered body will be too small, impairing the circulation of lubricating fluid through the internal pores, so the density ratio of the sintered body will be 95% or less. It is preferable that
  • the corner of the outer diameter end of the mold for the core rod interferes with the hill formed on the inner circumference of the sintered body, causing the hill of the sintered body to There is a risk of being destroyed.
  • the cross-sectional shape of the dynamic pressure groove is a perfect rectangle, and the more the groove is out of the rectangle, the more the dynamic pressure decreases. Therefore, if the corners of the outer diameter end of the mold are rounded as described above, the bottom corners of the dynamic pressure groove formed with this mold will be rounded and will collapse from the rectangular shape, so a drop in dynamic pressure can be avoided. I can't do it.
  • the corner on the side (one axial side) that interferes with the dynamic pressure groove when pulled out from the inner periphery of the sintered body is It is preferable to round off the corners of the other side).
  • the corner on one axial side of the groove bottom of the dynamic pressure groove is rounded more than the corner on the other axial side.
  • FIG. 2 is an axial cross-sectional view of the fluid dynamic bearing device incorporated in the fan motor of FIG. 1.
  • FIG. 3 is an axial cross-sectional view of a bearing sleeve (dynamic bearing) of the fluid dynamic bearing device of FIG. 2.
  • FIG. 4 is a cross-sectional view of the bearing sleeve taken along line XX in FIG. 3 in an axis orthogonal direction.
  • FIG. 2 is an axial cross-sectional view of the sizing mold and the sintered body, showing a state before the sintered body is inserted into the inner periphery of the die.
  • FIG. 6 is a side view of the core rod of the sizing mold of FIG.
  • FIG. 6 is a cross-sectional view of the sintered body and core rod of FIG. 5 in an axis orthogonal direction.
  • FIG. 2 is an axial cross-sectional view of the sizing mold and the sintered body, showing a state in which the sintered body is inserted into the inner periphery of the die.
  • 9 is a cross-sectional view of the sintered body and the core rod of FIG. 8 in a direction perpendicular to the axis.
  • FIG. 3 is a cross-sectional view of the sintered body and the core rod taken out from the inner periphery of the die in the direction orthogonal to the axis.
  • FIG. 2 is an axial cross-sectional view showing an example of a sintered body and a core rod taken out from the inner periphery of the die.
  • FIG. 6 is a side view showing a step of rounding the corners of the mold for the core rod.
  • FIG. 7 is an axial cross-sectional view showing another example of the sintered body and core rod taken out from the inner periphery of the die. It is a figure showing the shape (profile) of the dynamic pressure groove of a dynamic pressure bearing. It is a figure showing the shape (profile) of the dynamic pressure groove of a dynamic pressure bearing.
  • FIG. 1 conceptually shows an example of a fan motor.
  • the fan motor shown in the figure is built into, for example, a portable information device such as a notebook computer or a tablet terminal, and generates an airflow to cool a heat generating source such as a CPU.
  • This fan motor includes a fluid dynamic pressure bearing device 1, a motor base 5 constituting the stationary side of the motor, a rotor 3 fixed to a shaft member 2 of the fluid dynamic pressure bearing device 1, and blades attached to the rotor 3. 4, and a stator 6a and a magnet 6b that are arranged opposite to each other with a radial gap therebetween.
  • the stator 6a is attached to the housing 7 of the fluid dynamic bearing device 1, and the magnet 6b is attached to the rotor 3.
  • the magnet 6b and the rotor 3 rotate together.
  • an airflow is generated in an axial direction or a radially outward direction depending on the shape of the blades 4 attached to the rotor 3.
  • the fluid dynamic bearing device 1 includes a shaft member 2, a housing 7, a bearing sleeve 8 as a dynamic pressure bearing according to an embodiment of the present invention, and a seal member 9.
  • the internal space of the housing 7 is filled with lubricating oil.
  • the side where the shaft member 2 protrudes from the housing 7 in the axial direction (the upper side in FIG. 2) will be referred to as the "upper side”
  • the opposite side (the lower side in FIG. 2) will be referred to as the "lower side”.
  • this is not intended to limit the posture in which the fluid dynamic bearing device 1 is used.
  • the shaft member 2 is made of a metal material such as stainless steel. At least a region of the outer circumferential surface 2a of the shaft member 2 that faces the inner circumferential surface of the bearing sleeve 8 in the radial direction is a cylindrical surface that is not provided with irregularities such as dynamic pressure grooves. A convex spherical surface 2b is provided at the lower end of the shaft member 2. A rotor 3 is fixed to the upper end of the shaft member 2.
  • the housing 7 has a cylindrical portion 7a and a bottom portion 7b that closes the lower end opening of the cylindrical portion 7a.
  • the cylindrical portion 7a and the bottom portion 7b are integrally formed of resin or metal material.
  • a shoulder surface 7b2 arranged above the center portion is provided at the outer diameter side end of the upper end surface (inner bottom surface 7b1) of the bottom portion 7b.
  • a stator 6a and a motor base 5 are fixed to an outer circumferential surface 7a2 of the cylindrical portion 7a.
  • a thrust plate 10 is provided on the inner bottom surface 7b1 of the housing 7.
  • the thrust plate 10 is formed into a disk shape from a material that has better sliding properties than the material from which the housing 7 is formed.
  • the convex spherical surface 2b at the lower end of the shaft member 2 is supported in contact with the upper end surface of the thrust plate 10.
  • the thrust plate 10 may be omitted, and in that case, the convex spherical surface 2b of the shaft member 2 is supported in contact with the inner bottom surface 7b1 of the housing 7.
  • the seal member 9 is formed into an annular shape from a resin or metal material, and is fixed to the upper end of the inner circumferential surface 7a1 of the cylindrical portion 7a of the housing 7.
  • the lower end surface 9b of the seal member 9 is in contact with the upper end surface 8b of the bearing sleeve 8.
  • An annular seal space S is formed between the inner circumferential surface 9a of the seal member 9 and the outer circumferential surface 2a of the opposing shaft member 2.
  • this fluid dynamic pressure bearing device 1 is a so-called partial fill type in which lubricating oil and air are mixed inside the housing 7, but the present invention is not limited to this.
  • a so-called full-fill type may be used. In the case of the full-fill type, the oil level of the lubricating oil is always maintained within the axial range of the seal space S.
  • the bearing sleeve 8 is made of a cylindrical sintered body formed by sintering a compression molded body of metal powder, such as a copper-based sintered body containing copper as the main component or an iron-based sintered body containing iron as the main component. or a copper-iron sintered body whose main components are copper and iron.
  • the bearing sleeve 8 is fixed to the inner periphery of the housing 7 in an oil-impregnated state in which the internal pores of the sintered body are impregnated with lubricating oil.
  • the bearing sleeve 8 is fixed to the inner periphery of the cylindrical portion 7a of the housing 7 with its lower end surface 8c in contact with the shoulder surface 7b2 of the bottom portion 7b of the housing 7.
  • the bearing sleeve 8 is fixed to the inner circumferential surface 7a1 of the cylindrical portion 7a by press-fitting, adhesion, press-fitting adhesion (combination of press-fitting and adhesion), or the like.
  • the bearing sleeve 8 is fixed to the inner circumference of the housing 7 by sandwiching it between the seal member 9 and the shoulder surface 7b2 of the housing 7 from both sides in the axial direction. You can also.
  • a dynamic pressure generating portion is formed on the inner peripheral surface 8a of the bearing sleeve 8.
  • dynamic pressure generating portions A1 and A2 are provided at two locations in the axial direction of the inner circumferential surface 8a of the sintered body.
  • a plurality of dynamic pressure grooves G1 extending in a direction inclined with respect to the circumferential direction and arranged side by side in the circumferential direction are provided, and a plurality of dynamic pressure grooves G1 are provided between the plurality of dynamic pressure grooves G1 in the circumferential direction.
  • each of the dynamic pressure generating portions A1 and A2 includes a dynamic pressure groove G1 arranged in a herringbone shape, an annular hill portion G2, and a plurality of dynamic pressure grooves G1 extending from the annular hill portion G2 to both sides in the axial direction.
  • a plurality of inclined hill portions G3 are provided circumferentially between.
  • the inner diameter surfaces of the annular hill portion G2 and the inclined hill portion G3 are arranged on the same cylindrical surface.
  • the groove bottoms of the dynamic pressure grooves G1 are arranged on the same cylindrical surface.
  • the entire inner circumferential surface 8a of the bearing sleeve 8, including the bottom surface of the dynamic pressure groove G1, the inner diameter surfaces of the annular hill portion G2 and the inclined hill portion G3, is a molded surface formed by pressing a mold.
  • An axial groove 8d1 is formed on the outer peripheral surface 8d of the bearing sleeve 8.
  • a radial groove 8b1 and an annular groove 8b2 are formed in the upper end surface 8b of the bearing sleeve 8.
  • a radial groove 8c1 is formed in the lower end surface 8c of the bearing sleeve 8.
  • the annular groove 8b2 is provided to identify the up-down direction (ie, rotational direction) when the bearing sleeve 8 is assembled into the housing 7.
  • the axial groove 8d1 and the radial grooves 8b1 and 8c1 form a communication path that communicates the space faced by the bottom 7b of the housing 7 with the atmosphere in the fluid dynamic bearing device 1 (see FIG. 2). Note that if there is no particular need, any or all of the radial grooves 8b1 and 8c1, the annular groove 8b2, and the axial groove 8d1 may be omitted.
  • FIG. 4 is a cross-sectional view (cross-sectional view taken along line XX in FIG. 3) of the dynamic pressure groove G1 of the bearing sleeve 8 at the axial center, developed so that the circumferential direction is straight, and the radius It is a diagram with exaggerated dimensions in the direction (vertical direction in the figure).
  • the depth Hf of the dynamic pressure groove G1 is defined as the minimum diameter of the top surface (inner diameter surface) of each inclined hill portion G3 and the dynamic pressure groove adjacent to one circumferential side (left side in FIG. 4) of the inclined hill portion G3. This is the difference in diameter from the maximum diameter of the bottom surface of the pressure groove G1.
  • the circumferential width h of the inclined hill portion G3 is determined by the least square line L between the dynamic pressure groove G1 and the inclined hill portion G3 (line L of all the dynamic pressure grooves G1 in the circumferential direction in the axis orthogonal cross section shown in FIG.
  • the depths of all the dynamic pressure grooves G1 formed in the inner circumferential surface 8a of the bearing sleeve 8 are approximately uniform, and specifically, the variation in the depth Hf of each dynamic pressure groove G1 is set to be 1 ⁇ m or less. That is, the difference between the depth Hf (MAX) of the deepest dynamic pressure groove G1 and the depth Hf (MIN) of the shallowest dynamic pressure groove G1 among the plurality of dynamic pressure grooves G1 is 1 ⁇ m or less.
  • the density ratio of the bearing sleeve 8 is 80 to 95%.
  • the density ratio of the bearing sleeve 8 is a value measured in a dry state in which the internal pores of the sintered body are not impregnated with oil.
  • the variation in density ratio in the axial direction and the radial direction of the sintered body forming the bearing sleeve 8 is set to be 3% or less. Specifically, the difference in the density ratio between the three equal parts of the sintered body in the axial direction and the difference in the density ratio between the three equal parts in the radial direction of the sintered body are both 3%. The following shall apply.
  • a radial bearing gap is formed between the outer peripheral surface 2a of the shaft member 2 and the inner peripheral surface 8a of the bearing sleeve 8.
  • the pressure of the oil film generated in the radial bearing gap is increased by the dynamic pressure generating portions A1 and A2 (dynamic pressure grooves G1) formed on the inner circumferential surface 8a of the bearing sleeve 8, and this pressure (dynamic pressure action)
  • a radial bearing portion R is formed to support the member 2 in the radial direction (see FIG. 2).
  • the bearing sleeve 8 is manufactured through a compression molding process, a sintering process, and a sizing process in this order.
  • a cylindrical green compact having approximately the same shape as the bearing sleeve 8 in FIG. 3 is formed by compression molding raw material powder whose main raw material is metal powder.
  • the inner circumferential surface of the powder compact has a cylindrical shape with no irregularities.
  • An axial groove 8d1, a radial groove 8b1, and a radial groove 8c1 are formed on the outer peripheral surface, upper end surface, and lower end surface of the powder compact, respectively.
  • metal powder for example, one or more of copper-based powder (copper powder or copper-based alloy powder), iron-based powder (iron powder or iron-based alloy powder), copper-iron alloy powder ⁇ is used.
  • a mixed powder is used as the main raw material and mixed with various fillers such as molding aids and solid lubricants.
  • the green compact is heated at a predetermined sintering temperature to obtain a sintered body in which adjacent metal powder particles are bonded to each other via sintering necks.
  • the density ratio of the sintered body thus formed is 80 to 95%. Further, the variation in density ratio in the axial direction and the radial direction of the sintered body 28 is 3% or less.
  • the compression ratio in the compression molding step, the sintering temperature and time in the sintering step, etc. are set so that the density ratio of the sintered body satisfies the above.
  • the sizing mold 30 includes a core rod 31, an upper punch 32, a lower punch 33, and a die 34.
  • a mold 35 is formed on the outer peripheral surface of the core rod 31 .
  • the mold 35 has a hill portion 35c, an annular recess 35b, and an inclined recess 35a.
  • recesses 35a and 35b scattering regions are formed on the cylindrical outer peripheral surface of the core rod 31, and the region remaining between the inclined recesses 35a in the circumferential direction becomes a hill portion 35c.
  • the hill portion 35c, the annular recess 35b, and the inclined recess 35a have shapes that are the inversions of the unevenness of the dynamic pressure groove G1, the annular hill G2, and the inclined hill G3 shown in FIG. 3, respectively.
  • Each inclined recess 35a has a ratio (flatness) h'/Hf' of circumferential width h' [mm] to depth Hf' [ ⁇ m] of 0.1 ⁇ h'/Hf' ⁇ 0.65. (See Figure 7).
  • the depth Hf' of each inclined recess 35a is the maximum diameter between the bottom surface (outer diameter surface) of each inclined recess 35a and the outer diameter surface of the hill portion 35c adjacent to one side in the circumferential direction of the inclined recess 35a. It's the difference.
  • the core rod 31 is inserted into the inner circumference of the sintered body 28, and the axial width of the sintered body 28 is restrained by the upper and lower punches 32, 33. At this time, since the inner diameter of the sintered body 28 is slightly larger than the outer diameter of the core rod 31, a minute radial gap is formed between the inner peripheral surface of the sintered body 28 and the outer peripheral surface of the core rod 31. (See Figure 7).
  • the flatness h'/Hf' of the inclined recess 35a is larger than 0.1, so that the material of the sintered body 28 is pressed against the inclined recess 35a. (Meat) can enter easily. As a result, the material of the sintered body 28 can be filled up to the corners of the inclined recess 35a, so that the height of the inclined hill G3 formed in the inclined recess 35a, that is, the dynamic pressure adjacent to the inclined hill G3 is increased. The accuracy of the depth Hf of the groove G1 can be improved.
  • the depths of the dynamic pressure grooves G1 molded on the inner circumferential surface of the sintered body 28 can be made approximately uniform, and specifically, the depth Hf of all the dynamic pressure grooves G1 can be made substantially uniform.
  • the variation can be suppressed to 1 ⁇ m or less.
  • the sintered body 28, the core rod 31, and the upper and lower punches 32, 33 are raised, and the sintered body 28 and the core rod 31 are taken out from the inner periphery of the die 34.
  • the inner peripheral surface 28a of the sintered body 28 expands in diameter due to springback, and is separated from the mold 35 on the outer peripheral surface of the core rod 31 (see FIG. 10).
  • the core rod 31 is pulled out from the inner periphery of the sintered body 28 (that is, the bearing sleeve 8) in which the dynamic pressure groove G1, the annular hill portion G2, and the inclined hill portion G3 are formed on the inner circumferential surface.
  • the density ratio of the sintered body 28 is set to be high (80 to 95%), and the density ratio is substantially uniform in the axial direction and the radial direction.
  • the variation in the amount of springback is suppressed, and the diameter of the entire inner circumferential surface 28a of the sintered body 28 can be uniformly expanded.
  • the present invention is not limited to the above embodiments. Other embodiments of the present invention will be described below, but descriptions of points similar to the above embodiments will be omitted.
  • the dynamic pressure groove G1 When the core rod 31 is pulled out from the inner periphery of the sintered body 28 (bearing sleeve 8) in the axial direction (arrow direction in the figure), the corner e1 on the axial one side of the hill portion 35c is sintered. There is a risk that it will interfere with the ridges G2, G3 on the inner circumferential surface of the body 28, and the ridges G2, G3 may be damaged.
  • the corners of the outer diameter end of the mold 35 of the core rod 31 may be rounded.
  • the abrasive material 50 onto the workpiece (in this case, the core rod 31) using the spray device 55, the surface of the workpiece is polished by friction with the abrasive material 50, and the shape is formed.
  • the outer diameter end corner of the hill portion 35c of the mold 35 is rounded.
  • the core rod 31 is set to form a predetermined inclination angle with respect to the projection direction of the abrasive material 50.
  • the axis of the core rod 31 is inclined at a predetermined angle ⁇ with respect to the Y direction.
  • the end of the core rod 31 on one axial side (the opposite axial end, the right side in the figure) of the mold 35 is closer to the injection device than the end on the other axial side (the axial end, the left side in the figure).
  • the axis of the core rod 31 is inclined with respect to the Y direction perpendicular to the projection direction X of the abrasive material 50.
  • each hill portion 35c is rounded, the core rod 31 can be pulled out from the inner circumference of the sintered body 28 in the axial direction (in the direction of the arrow in FIG. 13).
  • the corner portion e1 and the hill portions G2 and G3 interfere with each other, it is possible to prevent the hill portions G2 and G3 from being bent.
  • the corner e2 on the other side in the axial direction is not rounded, the shape of the hill portions G2 and G3, and ultimately the shape of the dynamic pressure groove G1, can be approximated to a rectangular shape. can be secured.
  • the shape of the dynamic pressure groove G1 formed on the inner circumferential surface of the dynamic pressure bearing (bearing sleeve 8) is not limited to the above.
  • the dynamic pressure groove G1 inclined on one side with respect to the circumferential direction and the dynamic pressure groove G1 inclined on the other side with respect to the circumferential direction are made to be continuous, and
  • the inclined hill part G3 and the inclined hill part G3 inclined to the other side may be made to be continuous.
  • the dynamic pressure generating parts A1 and A2 may be spaced apart in the axial direction, and a cylindrical surface may be provided between them.
  • a dynamic pressure generating portion (for example, a spiral-shaped dynamic pressure groove and a hill portion) may be formed on one end surface of the dynamic pressure bearing in the axial direction.
  • the shaft member is provided with a flange portion, and the fluid film pressure generated in the thrust bearing gap between one axial end surface of the hydrodynamic bearing and the end surface of the flange portion of the shaft member is provided on the end surface of the hydrodynamic pressure bearing.
  • the shaft member is supported in a non-contact manner in the thrust direction by this pressure.
  • the hydrodynamic bearing is on the fixed side and the shaft member is on the rotating side is shown, but the present invention is not limited to this, and the shaft member may be on the fixed side and the hydrodynamic bearing on the rotating side.
  • the dynamic pressure bearing according to the present invention is not limited to the sintered oil-impregnated bearing in which the inside is impregnated with lubricating oil as described above, but can also be used in a dry state without impregnating lubricating oil. Furthermore, the fluid dynamic pressure bearing device 1 having a dynamic pressure bearing according to the present invention is applicable not only to a fan motor but also to a spindle motor of a disk drive device of an HDD and a polygon scanner motor of a laser beam printer.
  • Fluid dynamic pressure bearing device 2 Shaft member 3 Rotor 4 Vane 5 Motor base 6a Stator 6b Magnet 7 Housing 8 Bearing sleeve (dynamic pressure bearing) 9 Seal member 10 Thrust plate 28 Sintered body 30 Sizing mold 31 Core rod 32 Upper punch 33 Lower punch 34 Die 35 Molding die 35a Inclined recess 35b Annular recess 35c Hill portion 50 Abrasive material 55 Injector A1, A2 Dynamic pressure generating portion G1 Dynamic pressure groove G2 Annular hill portion G3 Inclined hill portion R Radial bearing portion S Seal space T Thrust bearing portion

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Power Engineering (AREA)
  • Sliding-Contact Bearings (AREA)
  • Connection Of Motors, Electrical Generators, Mechanical Devices, And The Like (AREA)

Abstract

L'invention porte sur un palier hydrodynamique (manchon de palier (8)) équipé d'un corps fritté dans lequel des parties de génération de pression dynamique (A1, A2) sont formées par moulage sur sa surface circonférentielle interne. Les parties de génération de pression dynamique (A1, A2) possèdent une pluralité de rainures de pression dynamique (G1) qui s'étendent dans une direction qui est inclinée par rapport à la direction circonférentielle, et une pluralité de sections de côte inclinées (G3) qui sont disposées entre les rainures de la pluralité de rainures de pression dynamique (G1) dans la direction circonférentielle. La largeur de direction circonférentielle h [mm] de chaque section en colline (G3) inclinée et la profondeur Hf [μm] de rainure de pression dynamique (G1) adjacente à ladite section en colline (G3) sur un côté de celle-ci dans la direction circonférentielle satisfont 0,1 < h/Hf < 0,65, et la variation de la profondeur Hf de la pluralité de rainures de pression dynamique (G1) n'est pas supérieure à 1 µm.
PCT/JP2023/030575 2022-09-16 2023-08-24 Palier hydrodynamique, dispositif de palier hydrodynamique et moteur WO2024057868A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022148262A JP2024043207A (ja) 2022-09-16 2022-09-16 動圧軸受、動圧軸受装置及びモータ
JP2022-148262 2022-09-16

Publications (1)

Publication Number Publication Date
WO2024057868A1 true WO2024057868A1 (fr) 2024-03-21

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PCT/JP2023/030575 WO2024057868A1 (fr) 2022-09-16 2023-08-24 Palier hydrodynamique, dispositif de palier hydrodynamique et moteur

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Country Link
JP (1) JP2024043207A (fr)
CN (2) CN220850360U (fr)
WO (1) WO2024057868A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05177545A (ja) * 1991-12-28 1993-07-20 Konica Corp ブラスト加工装置及び動圧式エアベアリング並びにポリゴンミラーユニット
JP2002061650A (ja) * 2000-08-22 2002-02-28 Hitachi Powdered Metals Co Ltd 動圧溝付き焼結軸受の製造方法
JP2007170577A (ja) * 2005-12-22 2007-07-05 Sony Corp 動圧軸受用部材の製造方法
JP2015064019A (ja) * 2013-09-24 2015-04-09 Ntn株式会社 焼結金属軸受、及びこの軸受を備えた流体動圧軸受装置
JP2016050648A (ja) * 2014-09-01 2016-04-11 Ntn株式会社 流体動圧軸受装置とこれに用いられる軸受部材及び軸部材
JP2018040458A (ja) * 2016-09-09 2018-03-15 Ntn株式会社 動圧軸受およびその製造方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH05177545A (ja) * 1991-12-28 1993-07-20 Konica Corp ブラスト加工装置及び動圧式エアベアリング並びにポリゴンミラーユニット
JP2002061650A (ja) * 2000-08-22 2002-02-28 Hitachi Powdered Metals Co Ltd 動圧溝付き焼結軸受の製造方法
JP2007170577A (ja) * 2005-12-22 2007-07-05 Sony Corp 動圧軸受用部材の製造方法
JP2015064019A (ja) * 2013-09-24 2015-04-09 Ntn株式会社 焼結金属軸受、及びこの軸受を備えた流体動圧軸受装置
JP2016050648A (ja) * 2014-09-01 2016-04-11 Ntn株式会社 流体動圧軸受装置とこれに用いられる軸受部材及び軸部材
JP2018040458A (ja) * 2016-09-09 2018-03-15 Ntn株式会社 動圧軸受およびその製造方法

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CN117722435A (zh) 2024-03-19
CN220850360U (zh) 2024-04-26

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