JP2010091002A - Sintered bearing and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sintered bearing supplying oil from a bearing surface while reducing the quantity of internally impregnated oil. <P>SOLUTION: A sintered body is impregnated with a resin, whereby the quantity of oil impregnated in internal pores thereof can be reduced. Pores 80 not impregnated with the resin are opened in a bearing surface (inner circumferential surface 8a), whereby the oil retained in the pores 80 can be supplied to a bearing clearance, and the pores 80 can be made to function as a filter for trapping contamination such as abrasive powder within the bearing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a sintered bearing having a bearing surface.

  The sintered bearing is formed by sintering a compression-molded body of metal powder, and has countless pores inside. For example, Patent Document 1 includes a sintered bearing (bearing sleeve) in which internal pores are impregnated with oil, and a shaft member inserted into the inner periphery of the sintered bearing, There is shown a bearing device that rotatably supports a shaft member with an oil film generated in a radial bearing gap between the shaft member and the outer peripheral surface thereof. During rotation of the shaft member, oil impregnated in the sintered bearing is supplied to the radial bearing gap from the pores opened in the bearing surface, thereby improving the lubricity between the shaft member and the sintered bearing. This bearing device is provided with a seal space, which absorbs the volume expansion associated with the temperature rise of the lubricant filled in the bearing device, thereby preventing the lubricant from leaking to the outside. ing.

JP 2007-250095 A JP 2005-337274 A

  However, in the bearing device as described in Patent Document 1, the amount of oil filled in the bearing increases as the internal pores of the sintered bearing are impregnated with the lubricating oil. Change also increases. Therefore, it is necessary to expand the volume of the seal space that absorbs the volume change of the oil, and there is a risk that the axial dimension of the bearing device is increased or the bearing rigidity is reduced due to the reduction of the bearing span.

  For example, as in Patent Document 2, if the internal pores of the sintered bearing are impregnated and cured, the internal pores of the sintered bearing are not impregnated with oil, and the amount of oil filled in the bearing can be reduced. Therefore, the above-mentioned problems can be avoided. However, if the entire sintered bearing is impregnated with resin, oil cannot be supplied to the bearing gap from the pores opened in the bearing surface of the sintered bearing, and there is a risk of poor lubrication due to insufficient oil.

  An object of the present invention is to provide a sintered bearing capable of reducing the amount of oil impregnated inside and supplying oil from the bearing surface.

  In order to solve the above-mentioned problems, the present invention provides a sintered bearing obtained by impregnating a sealing material into internal pores of a sintered body obtained by sintering a compression molded body of metal powder. In addition, the pores not impregnated with the sealing material are opened.

  Thus, the amount of oil impregnated in the internal pores can be reduced by impregnating the sintered body with the sealing material. In addition, since a lubricant (oil) can be retained in the pores by opening pores that are not impregnated with a sealing material on the bearing surface, lubrication can be achieved by supplying this oil to the sliding portion. Is increased. Further, the pores opened in the bearing surface exert a filter effect of capturing the wear powder and the like inside the bearing, thereby preventing the occurrence of contamination.

  As the sealing material, for example, a low-viscosity resin such as acrylic or epoxy, or a low melting point metal such as tin or zinc can be used. The low melting point metal means a metal material having a melting point lower than the sintering temperature of the sintered body.

  The sintered bearing as described above is obtained by sintering a compression molded body of metal powder to form a sintered body, and impregnating a sealing material from a region other than the bearing surface in the surface of the sintered body. It can be manufactured by opening pores not impregnated with a sealing material on the bearing surface.

  For example, when the sintered body has a cylindrical shape having a bearing surface on the inner peripheral surface, the sealing material is dropped from a region (outer peripheral surface) other than the bearing surface by dropping the sealing material on the outer peripheral surface of the sintered body. Can be impregnated into the pores. Alternatively, the pores can be impregnated into the pores from the outer peripheral surface by rolling the sintered body in a container containing the sealing material. Further, the sealing material can be impregnated from a region other than the bearing surface by immersing in the sealing material with the bearing surface covered with a coating agent.

  When the sintered body is impregnated with a sealing material and then sized (recompressed), the sealing material cured inside the pores of the sintered body is elastically repelled, and the dimensional accuracy of the sintered bearing (bearing Surface accuracy, inner diameter, outer diameter, axial dimension, etc.) may not be sufficiently increased. Therefore, it is preferable to impregnate the sealing material after sizing the sintered body. As described above, impregnation with resin from a region other than the bearing surface leaves pores not impregnated with resin on the bearing surface, which facilitates plastic deformation of the bearing surface. Can be processed well. Therefore, if there is no problem in the dimensional accuracy of the part other than the bearing surface, it is possible to size the sintered body after impregnating the sealing material.

  As described above, according to the present invention, it is possible to obtain a sintered bearing capable of reducing the amount of oil impregnated inside and supplying oil from the bearing surface.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a spindle motor for information equipment having a sintered bearing (bearing sleeve 8) according to an embodiment of the present invention. The spindle motor is used in a disk drive device such as an HDD, and includes a fluid dynamic bearing device 1 that rotatably supports the shaft member 2 in a non-contact manner, a disk hub 3 mounted on the shaft member 2, and a radius, for example. A stator coil 4 and a rotor magnet 5 are provided to face each other with a gap in the direction. The stator coil 4 is attached to the outer periphery of the motor bracket 6, and the rotor magnet 5 is attached to the inner periphery of the disk hub 3. The disk hub 3 holds one or a plurality of magnetic disks D (two in FIG. 1) on its outer periphery. In the spindle motor configured as described above, when the stator coil 4 is energized, the rotor magnet 5 rotates, and accordingly, the disk hub 3 and the disk D held by the disk hub 3 rotate integrally with the shaft member 2.

  A fluid dynamic pressure bearing device 1 shown in FIG. 2 includes a shaft member 2, a bottomed cylindrical housing 7, a bearing sleeve 8 as a sintered bearing, and a seal member 9 as main components. . In the following description, for convenience of description, the closed side of the housing 7 in the axial direction is defined as the lower side, and the opening side is defined as the upper side.

  The shaft member 2 is formed of a metal material such as stainless steel, for example, and includes a shaft portion 2a and a flange portion 2b provided at the lower end of the shaft portion 2a. The shaft portion 2a has a cylindrical outer peripheral surface 2a1 and a tapered surface 2a2 that is gradually reduced in diameter upward. The outer peripheral surface 2 a 1 of the shaft portion 2 a is disposed on the inner periphery of the bearing sleeve 8, and the tapered surface 2 a 2 is disposed on the inner periphery of the seal member 9. In addition to integrally forming the shaft portion 2a and the flange portion 2b, the shaft member 2 can also be partially formed of resin (for example, both end faces 2b1 and 2b2 of the flange portion 2b). The flange portion 2b is not necessarily provided. For example, a pivot bearing may be configured by forming a spherical portion at the end of the shaft portion and sliding the spherical portion and the bottom portion 7b of the housing 7 in contact with each other. it can.

  The bearing sleeve 8 is composed of a sintered body obtained by sintering a compression molded body of metal powder, and is formed in a substantially cylindrical shape in this embodiment. The inner peripheral surface 8a of the bearing sleeve 8 functions as a radial bearing surface, and the lower end surface 8c functions as a thrust bearing surface. For example, a resin is impregnated as a sealing material in a region excluding the bearing surfaces of the bearing sleeve 8 (radial bearing surface and thrust bearing surface, the same applies hereinafter). 3 (a) and 3 (b), the region impregnated with the resin is indicated by hatching. In the present embodiment, of the surface of the bearing sleeve 8, the inner peripheral surface 8a (radial bearing surface), the lower end surface 8c (thrust bearing surface), and the upper end surface 8b are not impregnated with resin, and are opened in the outer peripheral surface 8d. The resin is impregnated with the pores inside and the pores connected to the pores. Accordingly, the inner peripheral surface 8a and the lower end surface 8c serving as bearing surfaces are formed of a sintered metal base metal material (copper or copper and iron in the present embodiment), and over the entire bearing surface, Innumerable pores that are not impregnated with resin are opened. Specifically, as conceptually shown in FIG. 3 (b), the pore 80 communicating with the bearing surface 8a (8c) is provided with a region not impregnated with resin to a predetermined depth (region where no resin is present). Lubricating oil can be retained in the region.

  On the inner peripheral surface 8a of the bearing sleeve 8, a radial dynamic pressure generating portion for generating a dynamic pressure action on the fluid film (oil film) in the radial bearing gap is formed. In this embodiment, as shown in FIG. In addition, two dynamic pressure groove regions in which herringbone-shaped dynamic pressure grooves 8a1 and 8a2 are arranged are formed apart from each other in the axial direction. Of the two dynamic pressure groove regions, portions with cross hatching except for the dynamic pressure grooves 8a1 and 8a2 are hill portions. In the upper dynamic pressure groove region, the dynamic pressure groove 8a1 is formed in an axially asymmetric shape, specifically, the axial direction of the upper groove with respect to the belt-like portion formed in the substantially central portion in the axial direction of the hill. The dimension X1 is larger than the axial dimension X2 of the lower groove (X1> X2). In the lower dynamic pressure groove region, the dynamic pressure groove 8a2 is formed in an axially symmetrical shape. Due to the unbalance of the pumping ability in the vertical dynamic pressure groove region described above, the oil filled between the inner peripheral surface 8a of the bearing sleeve 8 and the outer peripheral surface of the shaft portion 2a is rotated during the rotation of the shaft member 2. It will be pushed downward.

  A thrust dynamic pressure generating portion for generating a dynamic pressure action on the oil film in the thrust bearing gap is formed on the lower end surface 8 c of the bearing sleeve 8. In the present embodiment, the thrust dynamic pressure generating portion has a spiral shape as shown in FIG. On the outer peripheral surface 8d of the bearing sleeve 8, axial grooves 8d1 are formed at a plurality of locations (for example, three locations) at equal intervals in the circumferential direction. In a state where the outer peripheral surface 8d of the bearing sleeve 8 and the inner peripheral surface 7c of the housing 7 are fixed, the axial groove 8d1 functions as an oil communication path, and the pressure balance inside the bearing is maintained within an appropriate range by this communication path. be able to.

  The housing 7 has a cup shape opened in one axial direction, and integrally includes a cylindrical side portion 7a in which a bearing sleeve 8 is held on the inner periphery and a bottom portion 7b that closes the lower end of the side portion 7a. The material of the housing 7 is not particularly limited, and a metal such as brass or an aluminum alloy, an inorganic material such as resin, glass, or the like can be used. As the resin material, either a thermoplastic resin or a thermosetting resin can be used. Further, if necessary, a resin composition in which various additives such as carbon nanomaterials such as glass fiber, carbon fiber, and carbon black, and graphite are blended can be used. On the upper end surface 7b1 of the bottom 7b of the housing 7, for example, a spiral dynamic pressure groove is formed as a thrust dynamic pressure generating portion for generating a dynamic pressure action on the oil film in the thrust bearing gap (not shown).

  The seal member 9 is formed in an annular shape with, for example, a resin material or a metal material, and is disposed on the inner periphery of the upper end portion of the side portion 7 a of the housing 7. The inner peripheral surface 9a of the seal member 9 is opposed to the tapered surface 2a2 provided on the outer periphery of the shaft portion 2a in the radial direction, and a seal space S in which the radial dimension is gradually reduced downward is formed therebetween. The Due to the capillary force of the seal space S, the lubricating oil is drawn into the inside of the bearing, and oil leakage is prevented. In this embodiment, since the taper surface 2a2 is formed on the shaft portion 2a side, the seal space S also functions as a centrifugal force seal.

  The oil level of the lubricating oil filled in the internal space of the housing 7 sealed with the seal member 9 is maintained within the range of the seal space S. That is, the seal space S has a volume that can absorb the volume change of the lubricating oil. In the present embodiment, as described above, the internal pores of the bearing sleeve 8 are impregnated with the resin, so that the amount of oil entering the internal pores is reduced, thereby reducing the total amount of oil filled in the bearing. Therefore, compared with the case where the resin is not impregnated in the internal pores of the bearing sleeve 8, the volume change of the oil with the temperature is reduced, so that the volume of the seal space S can be reduced. Thereby, since the axial direction dimension of the sealing member 9 can be reduced, size reduction of the fluid dynamic pressure bearing apparatus 1 is achieved. Alternatively, the axial rigidity (bearing span) of the first and second radial bearing portions R1 and R2 can be expanded without changing the size of the device, thereby improving the bearing rigidity (especially moment rigidity).

  In the fluid dynamic bearing device 1 having the above configuration, when the shaft member 2 rotates, a radial bearing gap is formed between the inner peripheral surface 8a (radial bearing surface) of the bearing sleeve 8 and the outer peripheral surface 2a1 of the shaft portion 2a. . The oil film pressure generated in the radial bearing gap is increased by the dynamic pressure grooves 8a1 and 8a2 formed on the inner peripheral surface 8a of the bearing sleeve 8, and the dynamic pressure action allows the shaft portion 2a to be rotatably supported in a non-contact manner. A first radial bearing portion R1 and a second radial bearing portion R2 are configured.

  At the same time, a thrust bearing gap between the upper end surface 2b1 of the flange portion 2b and the lower end surface 8c (thrust bearing surface) of the bearing sleeve 8, and the lower end surface 2b2 of the flange portion 2b and the upper portion of the bottom portion 7b of the housing 7 An oil film is formed in the thrust bearing gap with the end surface 7b1, and the pressure of the oil film is increased by the dynamic pressure action of the dynamic pressure groove. By this dynamic pressure action, the first thrust bearing portion T1 and the second thrust bearing portion T2 are configured to support the flange portion 2b in a non-contact manner so as to be rotatable in both thrust directions.

  At this time, as described above, since the bearing surface (inner peripheral surface 8a, lower end surface 8c) of the bearing sleeve 8 is not impregnated with resin, the pores opened in the bearing surface can function as an oil reservoir. . By supplying the oil retained in the pores to the radial bearing gap or the thrust bearing gap, the lubricity between the shaft member 2 and the bearing sleeve 8 is enhanced. Further, since the pores opened in the bearing surface function as a filter that captures wear powder generated by contact between the bearing sleeve 8 and the shaft member 2, contamination can be prevented from entering the oil film in the bearing gap. In particular, the filter effect can be enhanced by allowing a plurality of pores opened in the bearing surface to communicate with each other inside the bearing sleeve 8 and allowing oil to pass through a path inside the bearing.

  Hereinafter, the manufacturing method of the sintered bearing (bearing sleeve 8) which concerns on embodiment of this invention is demonstrated based on drawing. The bearing sleeve 8 is manufactured through a compression molding process (see FIG. 4), a sintering process (not shown), a sizing process (see FIG. 5), and a resin impregnation process (see FIG. 6).

  In the compression molding step, first, as shown in FIG. 4A, the metal powder M is filled into a cylindrical cavity surrounded by the die 11, the core rod 12, and the lower punch 13. As the metal powder M to be filled, for example, copper powder, copper alloy powder, or those in which iron powder is blended are used, and an appropriate amount of graphite or the like is added to and mixed with the metal powder as necessary. From this state, the upper punch 14 is lowered, the metal powder M is compressed from the upper side in the axial direction (see FIG. 4B), and then the compression molded body Ma is released from the mold (see FIG. 4C). ).

  In the sintering step, the compression molded body Ma is sintered at a predetermined sintering temperature, whereby a cylindrical sintered body 15 is obtained. The sintering process is performed, for example, in a vacuum or in an inert gas atmosphere, and is sintered at a predetermined sintering temperature. As described above, when copper powder or iron powder is used as the metal powder M, the sintering temperature is set within a range of about 700 to 1100 ° C.

  In the sizing process, the inner peripheral surface, outer peripheral surface, and axial dimension of the sintered body 15 impregnated with resin are corrected to appropriate dimensions, and dynamic pressure generating portions are formed on the inner peripheral surface and the lower end surface. Specifically, first, as shown in FIG. 5 (a), as shown in FIG. 5 (b), the sintered body 15 is supported (restrained) from both sides in the axial direction by the upper and lower punches 18 and 19. The sintered body 15 is press-fitted into the inner periphery of the die 16. As a result, the sintered body 15 is deformed by receiving a pressing force from the die 16 and the upper and lower punches 18 and 19, and is sized in the radial direction. Along with this, the inner peripheral surface 15a of the sintered body 15 is pressed against the molding die 17a of the core rod 17, and the irregular shape of the molding die 17a is transferred to the inner peripheral surface 15a of the sintered body 15, and moves on this surface. A pressure groove is formed. At the same time, the lower end surface 15c of the sintered body 15 is pressed against a forming die (not shown) of the upper end surface 19a of the lower punch 19, and a dynamic pressure groove is formed on this surface. Then, as shown in FIG.5 (c), the die | dye 16 is lowered | hung and the sintered compact 15 is extracted from the die | dye 16, and the radial direction compression force is cancelled | released. At this time, with release from the die 16, a radial spring back is generated in the sintered body 15, a minute gap is formed between the sintered body 15 and the core rod 17, and both are separable. Become. Then, by pulling the sintered body 15 out of the core rod 17, the sintered body 15 is released. In FIG. 5, the depths of the dynamic pressure grooves and the molding die 17a are exaggerated for easy understanding.

  In the resin impregnation step, the resin is impregnated in a region excluding the radial bearing surface (inner peripheral surface 15a) and the thrust bearing surface (end surface 15c) of the sintered body 15. As the resin used at this time, a resin having a low viscosity is suitable so that the internal pores of the sintered body 15 are easily impregnated. For example, an acrylic resin (viscosity: about 20 mPa · s) or an epoxy resin (viscosity: about 40 to 50 mPa · s) can be preferably used. Moreover, you may mix | blend additives, such as a hardening | curing agent, in the resin solution.

  Specifically, as shown in FIG. 6, the sintered body 15 is arranged so that the axial direction is horizontal, and a shaft 41 is inserted into the inner periphery of the sintered body 15, so that the sintered body 15 and the shaft 41 are inserted. The resin is dropped from the nozzle 40 onto the outer peripheral surface 15d of the sintered body 15 while rotating the nozzle integrally. The resin dropped on the outer peripheral surface 15d penetrates into the inner diameter side of the sintered body 15 (see arrows in FIG. 6A) and spreads on both sides in the axial direction (see arrows in FIG. 6B). At this time, the dripping amount and dropping speed of the resin, the viscosity of the resin, and the resin soaked into the sintered body 15 do not reach the inner peripheral surface 15a serving as the radial bearing surface and the end surface 15c serving as the thrust bearing surface. The rotational speed of the sintered body 15 or the porosity (density) of the sintered body 15 is adjusted. Further, as shown in the figure, if the nozzle 40 is arranged offset from the axially central portion of the sintered body 15 to the side away from the end surface 15c serving as the thrust bearing surface, the resin is disposed on the end surface 15c serving as the thrust bearing surface. Can be prevented. Thereafter, the resin is cured to complete the resin impregnation step.

  As described above, by performing the sizing step before the resin impregnation step, it is possible to size the sintered body in which the internal pores are not impregnated with the resin. Can be increased sufficiently.

  Contrary to the above, when the sizing process is performed after the resin impregnation process, there is a risk that the dimensional accuracy of parts other than the bearing surface may be reduced due to the repulsion of the resin. Since pores not impregnated with resin (that is, pores having a hollow inside) are left on the inner peripheral surface 15a and the lower end surface 15c, the bearing surface of the sintered body 15 is easily plastically deformed in the sizing process. Surface molding accuracy can be secured. In particular, as described above, when the dynamic pressure generating portion (dynamic pressure groove) is formed on the bearing surface, the amount of plastic deformation due to sizing is larger than that of a smooth bearing surface. It is effective to leave the surface and improve the moldability. Therefore, the sizing process may be performed after the resin impregnation process if there is no problem in the dimensional accuracy other than the bearing surface depending on the type of resin, the porosity of the sintered body, or the use of the bearing. Is possible.

  The present invention is not limited to the above embodiment. Hereinafter, other embodiments of the present invention will be described, but the same reference numerals are given to portions having the same configurations and functions as those of the above-described embodiments, and description thereof will be omitted.

  In the above embodiment, in the resin impregnation step of the bearing sleeve 8, the resin is directly dropped from the nozzle 40 to the outer peripheral surface 15 d of the sintered body 15, but not limited to this, as shown in FIG. It is also possible to impregnate the sintered body 15 with a resin by using an application member 42 made of felt or the like impregnated with a resin. Specifically, the resin impregnated in the application member 42 is made to contact the outer peripheral surface 15d of the sintered body 15 and the sintered body 15 is rotated with respect to the application member 42 so that the resin impregnated in the application member 42 is sintered. Pulled into the side. As in the example shown in FIG. 5, the resin drawn into the sintered body 15 permeates both the inner diameter side and the axial direction, thereby impregnating the resin in the pores in a predetermined region of the sintered body 15. As described above, since the application member 42 and the sintered body 15 are brought into contact with each other in a predetermined axial region, the resin is supplied from the entire contact region to the sintered body 15, so that the inside of the sintered body 15 is uniform. Can be impregnated with resin. Further, as shown in the figure, if the resin impregnation is performed while dripping the resin from the nozzle 40 to the application member 42, the application member 42 can be always impregnated with abundant resin. An amount of resin can be supplied. Further, in order to prevent the resin from reaching the thrust bearing surface, the application member 42 is separated from the end surface 15c serving as the thrust bearing surface with respect to the central portion in the axial direction of the sintered body 15 in the same manner as the nozzle 40 shown in FIG. It is preferable to arrange it in an offset direction.

  Further, in the resin impregnation step shown in FIG. 5, the resin is dropped from the single nozzle 40. However, the present invention is not limited to this. For example, the resin may be dropped from the plurality of nozzles 40 as shown in FIG. Simultaneously with the dropping of the resin, if a high-speed air flow 50 is passed through the inner periphery of the sintered body 15 by an air blower or the like as shown in the drawing, the pressure at the inner peripheral portion of the sintered body 15 is reduced, and the outer peripheral surface 15d. It becomes easy to impregnate the resin dripped in the inner diameter side.

  In the above embodiment, in the resin impregnation step, the resin is dropped onto the outer peripheral surface 15d from the nozzle 40 above the sintered body 15. However, the present invention is not limited to this. For example, as shown in FIG. The resin may be impregnated by rolling the sintered body 15 in the container 61 having a shallow bottom. Alternatively, instead of rolling the sintered body 15, as shown in FIG. 10, the sintered body 15 may be rotated on the spot in a state where the sintered body 15 is in contact with the resin 60. In addition, according to the method shown in FIG.9 and FIG.10, resin will be impregnated to the end surface 15c of the sintered compact 15 used as a thrust bearing surface, However, Resin is not impregnated into 15a used as a radial bearing surface, The radial bearing surface has pores that are not impregnated with resin. Thus, if the pore which is not impregnated with resin is opened in at least a part of the bearing surface, the effect of the present invention can be obtained.

  Alternatively, as shown in FIG. 11, in the sintered body 15, the inner peripheral surface 15 a serving as the radial bearing surface and the lower end surface 15 c serving as the thrust bearing surface are covered with the covering materials 71 and 72 and sintered in this state. It is also possible to impregnate the resin by immersing the body 15 in the resin solution. The covering material is preferably formed of a material capable of preventing the resin from entering by a physical or chemical action. For example, a film containing polyethylene or a substance containing water such as gel-like polyvinyl alcohol can be used. As a result, the resin is impregnated from the pores opened in the regions of the sintered body 15 that are not covered with the covering materials 71 and 72 (the outer peripheral surface 15d and the upper end surface 15b in the illustrated example). When the impregnation is completed, the sintered body 15 is taken out from the resin solution, and the covering materials 71 and 72 are removed. As described above, the resin can be impregnated in the sintered body 15 except for the radial bearing surface (inner peripheral surface 15a) and the thrust bearing surface (lower end surface 15c).

  In the above embodiment, the resin is used as the sealing material impregnated in the sintered bearing. However, the present invention is not limited to this. For example, a low melting point metal such as tin, zinc, magnesium alloy, or solder is used. You can also. In this case, if all the pores of the sintered bearing are impregnated with a metal material, deformation due to sizing becomes difficult, and the desired dimensional accuracy may not be obtained. Therefore, when a metal material is impregnated as a sealing material, in order to facilitate dimensional adjustment by sizing, resin impregnation is performed after the sizing process, or pores that are not impregnated with the sealing material are opened on the bearing surface. Is particularly effective.

  In the above embodiment, the inner peripheral surface 8a and the lower end surface 8c of the bearing sleeve 8 function as a bearing surface. However, the present invention is not limited to this. For example, only the inner peripheral surface is a bearing surface. The manufacturing method of the present invention can also be applied to a solid bearing.

It is sectional drawing of a spindle motor. It is sectional drawing of a fluid dynamic pressure bearing apparatus. (A) is sectional drawing of a bearing sleeve, (b) is the elements on larger scale of the sectional drawing, (c) is a bottom view of a bearing sleeve. (A)-(c) is sectional drawing which shows the compression molding process of a bearing sleeve. (A)-(c) is sectional drawing which shows the sizing process of a bearing sleeve. (A) is a cross-sectional view which shows the resin impregnation process of a bearing sleeve, (b) is the longitudinal cross-sectional view. It is sectional drawing which shows the other example of the resin impregnation process of a bearing sleeve. It is sectional drawing which shows the other example of the resin impregnation process of a bearing sleeve. It is sectional drawing which shows the other example of the resin impregnation process of a bearing sleeve. It is sectional drawing which shows the other example of the resin impregnation process of a bearing sleeve. It is sectional drawing which shows the other example of the resin impregnation process of a bearing sleeve.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fluid dynamic pressure bearing apparatus 2 Shaft member 7 Housing 8 Bearing sleeve (sintered bearing)
9 Seal member 15 Sintered body 40 Nozzle R1, R2 Radial bearing portion T1, T2 Thrust bearing portion S Seal space

Claims (9)

A sintered bearing formed by impregnating a sealing material into the internal pores of a sintered body obtained by sintering a compression molded body of metal powder,
A sintered bearing having pores that are not impregnated with a sealing material on the bearing surface.   The sintered bearing according to claim 1, wherein the sealing material is a resin.   The sintered bearing according to claim 1, wherein the sealing material is a low melting point metal.   A sintered compact is formed by sintering a compression molded body of metal powder, and the sealing material is not impregnated by impregnating the sealing material from a region other than the bearing surface in the surface of the sintered body. A method of manufacturing a sintered bearing in which pores are opened in the bearing surface.   The method for manufacturing a sintered bearing according to claim 4, wherein the sintered body has a cylindrical shape having a bearing surface on the inner peripheral surface, and the sealing material is impregnated by dropping the sealing material on the outer peripheral surface of the sintered body.   The sintered bearing according to claim 4, wherein the sintered body has a cylindrical shape having a bearing surface on the inner peripheral surface, and the sealing material is impregnated by rolling the sintered body in a container containing the sealing material. Method.   The method for manufacturing a sintered bearing according to claim 4, wherein the sealing material is impregnated by dipping in the sealing material in a state where the bearing surface is covered with a coating agent.   The method for manufacturing a sintered bearing according to claim 4, wherein the sintered body is impregnated with a sealing material after sizing.   The method for manufacturing a sintered bearing according to claim 4, wherein sizing is performed after impregnating the sintered body with a sealing material.

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