JP2006177387A5 - - Google Patents

Claims (15)

The powder material was charged rod-like inner shape type for primary molding in the outer mold for primary molding, which is inserted inside, the compression molding in the axial direction by the upper die contact and lower die for the primary molding a primary molding step for molding the primary molded article,
The primary molded body is inserted into an outer mold for secondary molding in which a rod-shaped inner mold for secondary molding is inserted, and the upper mold or the lower mold facing the primary molded body is pressed. The inner peripheral part of the surface is compression-molded in the axial direction using the upper mold and the lower mold for secondary molding protruding in the pressing direction from the outer peripheral part, and the inner peripheral part is more than the outer peripheral part. secondary molding step and to produce a secondary molded member for the sleeve is a high compression ratio
A method for manufacturing a sleeve for a hydrodynamic bearing. 2. The hydrodynamic bearing according to claim 1, wherein either one of the upper mold and the lower mold for primary molding has the pressing surface substantially flat, and the one end surface is formed to be substantially flat. For manufacturing a sleeve. The inner peripheral portion near the pressing surface of the upper mold or the lower mold for the secondary molding projecting in the pressing direction than the outer peripheral portion close to the upper mold or the lower mold, the flat surface of the primary molded body The manufacturing method of the sleeve for hydrodynamic fluid bearings of Claim 2 which opposes and opposes . A method of manufacturing a hydrodynamic bearing sleeve for forming a molded article for a sleeve having a stepped recess in which a thrust flange is accommodated and a thrust plate is fitted and fixed on the outer side in the axial center direction. ,
The powder material is filled in the outer shape die for primary molding, which is inserted into a rod-like inner shape type for primary molding, a first stepped protrusion of substantially a shape corresponding to the stepped recess A primary molding step in which a primary molded body is molded by compression molding in the axial direction using an upper mold or a lower mold for primary molding provided with
The primary molded body is inserted into an external mold for secondary molding in which a rod-shaped inner mold for secondary molding is inserted, and a second step having a shape substantially corresponding to the stepped recess. A secondary molding step of producing a secondary molded body by compression molding in the axial direction using an upper mold or a lower mold for secondary molding provided with a convex portion;
Have
The first stepped protrusion and the second stepped protrusion are:
The axial dimension corresponding to the thrust flange accommodating space of the second stepped convex portion is smaller than the axial dimension corresponding to the thrust flange accommodating space of the first stepped convex portion,
The axial dimension corresponding to the thrust plate storage space of the second stepped convex portion is smaller than the axial dimension corresponding to the thrust plate storage space of the first stepped convex portion,
The ratio of the axial dimension of the second stepped protrusion corresponding to the thrust flange storage space to the axial dimension of the first stepped protrusion corresponding to the thrust flange storage space is greater than the ratio of the axial dimension of the second stepped protrusion corresponding to the thrust flange storage space. The ratio of the axial dimension of the second stepped convex portion corresponding to the thrust plate storage space to the axial dimension of the first stepped convex portion corresponding to the thrust plate storage space is small. A method for manufacturing a sleeve for a hydrodynamic bearing. A molded body having a shape in which a rod-shaped inner mold is inserted into an outer mold and filled with a powder material, compression-molded in the axial direction by an upper mold and a lower mold, and having a stepped recess on the inner peripheral side A method for manufacturing a hydrodynamic bearing sleeve for molding
A method for manufacturing a sleeve for a hydrodynamic bearing, wherein a powder material finer than other places is filled in an outer peripheral portion of the stepped recess in a space filled with the powder material, and compression molding is performed. The method for producing a sleeve for a hydrodynamic bearing according to any one of claims 1 to 5, further comprising a sealing treatment step of sealing pores existing on the surface of the secondary compact. The method of manufacturing a sleeve for a hydrodynamic fluid bearing according to claim 6, wherein in the sealing treatment step, the air hole is impregnated with a sealing agent that does not allow the working fluid of the hydrodynamic bearing to pass through and cured. A spindle motor equipped with a hydrodynamic bearing sleeve manufactured by the manufacturing method according to claim 1. A cylindrical outer peripheral surface;
A cylindrical inner peripheral surface into which the shaft is inserted;
A stepped portion provided at the end in the axial direction, the inner peripheral portion being recessed in the axial direction than the outer peripheral portion
Have
A sleeve for a hydrodynamic bearing, which is made of a sintered metal material and has an inner peripheral side portion corresponding to the stepped portion having a higher compressibility than the outer peripheral side portion. The hydrodynamic bearing sleeve according to claim 9, further comprising a stepped portion on one end side of which a thrust plate is inserted and fixed so as to face the shaft. The hydrodynamic bearing sleeve according to claim 9 or 10, wherein the shaft projects in an axial direction from the stepped portion. The sleeve for a hydrodynamic fluid bearing according to any one of claims 9 to 11, wherein a hole existing on a surface of the sleeve for the hydrodynamic bearing is sealed. The sleeve for a hydrodynamic bearing according to claim 10, wherein the hole is impregnated with a sealing agent that does not allow the working fluid of the hydrodynamic bearing to pass through and cured. A spindle motor on which the hydrodynamic bearing sleeve according to claim 9 is mounted. A hard disk device on which the spindle motor according to claim 8 is mounted.