JP2009008160A - Fluid dynamic pressure bearing mechanism, manufacturing method of fluid dynamic pressure bearing, and motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily apply an oil repellent agent in an appropriate range in a tapered seal part that holds lubricating oil in a tapered gap of a fluid dynamic bearing. <P>SOLUTION: A bearing mechanism 2 includes a cap 25 for covering the outside face and the upper face of a sleeve, and an annular tapered part 2412 covering the outer periphery of the cap 25 and its diameter increased toward the upper direction. The tapered seal part 271 for holding the lubricating oil is formed in the tapered gap formed by the outside face of the cap 25 and the inside face 2414 of the annular tapered part 2412. In the tapered seal part 271, a first step 2417 is formed at an upper part of the inside face 2414 of the annular tapered part 2412, and a second step 2515 is formed at an upper part of the outside face of the cap 25. By these steps, the oil repellent agent can be easily applied in an appropriate range. Further, axial positions of the first step 2417 and the second step 2515 are substantially matched with each other, and the lubricating oil is stably held in the tapered seal part 271. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fluid dynamic pressure bearing mechanism used for an electric motor.

  In a small spindle motor (hereinafter referred to as “motor”) used in a recording disk drive or the like, a low-noise fluid dynamic bearing mechanism is often used as a bearing mechanism, and the fluid dynamic bearing mechanism is tapered. Is provided with a taper seal portion that holds the lubricating oil by utilizing the capillary force in the gap (hereinafter referred to as “taper gap”). For example, in Patent Document 1, the lubricating oil is provided between the cover member attached to the upper portion of the sleeve and the outer surface of the shaft while circulating the lubricating oil in order along the inner surface, the lower surface, the outer surface, and the upper surface of the sleeve. A technique is disclosed in which lubricating oil is retained by an inner tapered seal portion and an outer tapered seal portion provided between a sleeve housing that covers the outer surface of the sleeve and the outer surface of the cover member.

  On the other hand, in order to extend the life of the fluid dynamic pressure bearing mechanism, it is necessary to prevent the lubricating oil from splashing from the taper seal portion and adhering to other portions than the bearing portion or the lubricating oil being insufficient. Therefore, conventionally, by applying an oil repellent near the lubricating oil interface of the taper seal part, measures have been taken to prevent the interface from moving out of the taper seal part or the scattered lubricating oil from spreading. It has been. For example, in Patent Document 2, it is easy to recognize the application state by adding a colorant or a fluorescent agent to an oil repellent that is generally colorless and transparent, and to efficiently check whether or not the oil repellent is applied and the application range. Techniques to do are disclosed.

In Patent Document 3, in order to set the thrust bearing gap to a predetermined dimension when the fluid dynamic pressure bearing mechanism is assembled, the lower surface of the flange portion of the shaft member is brought into contact with the inner bottom surface of the housing, and the lower surface of the sleeve is A method has been proposed in which the shaft member and the sleeve are moved relative to the housing after being brought into contact with the upper surface.
JP 2005-155912 A JP 2001-27242 A JP 2003-239974 A

  By the way, in the fluid dynamic pressure bearing mechanism, in order to prevent leakage of the lubricating oil from the taper seal portion, assembly accuracy when forming the taper gap and accurate application of the oil repellent agent to the oil repellent region provided around the taper seal portion are required. It becomes important.

  The present invention has been made in view of the above problems, and has as its main purpose to accurately apply an oil repellent to a fluid dynamic pressure bearing, and further to stably hold the lubricating oil at the taper seal portion of the bearing mechanism. Also aimed.

  The invention according to claim 1 is a fluid dynamic pressure bearing mechanism used for an electric motor, wherein a cylindrical sleeve centering on a predetermined central axis, and an upper end inserted into the sleeve from the sleeve. A projecting shaft, a lubricating oil in which a fluid dynamic pressure is induced that fills a radial gap between the inner surface of the sleeve and the outer surface of the shaft and generates a supporting force to support the shaft; The lubricating oil in the gap between the upper cap that covers the upper surface of the sleeve and the upper surface of the sleeve and the outer surface of the upper cap and has an opening into which the upper end is inserted, and between the outer surface of the upper cap An upper cylindrical portion that forms a capillary seal portion that is held by surface tension, and a dynamic pressure that communicates with the lower portion of the radial gap or the lower portion as the fluid dynamic pressure is generated when the shaft rotates. The lubricating oil flows in from a gap, and communicates the lower part of the radial gap or the dynamic pressure gap with the capillary seal part, the pore provided in the sleeve or the sleeve, and the sleeve A gap between the upper cap and the capillary seal part and the upper part of the radial gap, and a second flow path through which the lubricating oil flows from the first flow path. A first step portion that is recessed radially outward from the inner side surface is formed above the lubricating oil on the inner side surface in the central axis direction, and more than the lubricating oil on the outer side surface of the upper cap. A second step portion that is recessed radially inward from the outer surface is formed in the upper direction of the central axis, and an oil repellent film is formed on the surfaces of the first step portion and the second step portion. ing.

  A second aspect of the present invention is the fluid dynamic pressure bearing mechanism according to the first aspect, wherein the positions of the first step portion and the second step portion in the central axis direction substantially coincide with each other.

  The invention according to claim 3 is the fluid dynamic pressure bearing mechanism according to claim 1 or 2, wherein the positions of the upper end of the upper cylindrical portion and the upper surface of the upper cap in the central axis direction substantially coincide.

  Invention of Claim 4 is the fluid dynamic pressure bearing mechanism in any one of Claim 1 thru | or 3, Comprising: The said 1st level | step difference part is formed in the upper part of the said inner surface of the said upper cylindrical part, A second stepped portion is formed at the upper portion of the outer surface of the upper cap, and the first stepped portion and the upper end surface of the upper cylindrical portion are connected with a smooth curved surface, and the second stepped portion and A smooth curved surface is connected to the upper surface of the upper cap.

  The invention according to claim 5 is the fluid dynamic pressure bearing mechanism according to any one of claims 1 to 4, wherein the first stepped portion is formed in the circumferential direction on the inner side surface of the upper cylindrical portion. It is a lower edge of the groove, and the second step portion is a lower edge of the groove formed in the circumferential direction on the outer surface of the upper cap.

  A sixth aspect of the present invention is the fluid dynamic pressure bearing mechanism according to any one of the first to fifth aspects, comprising a lower cylindrical portion and an upper cylindrical portion that cover a lower portion of the outer surface of the sleeve. A bottomed cylindrical sleeve housing is further provided.

  The invention according to claim 7 is the fluid dynamic pressure bearing mechanism according to claim 6, wherein the sleeve housing connects between the upper cylindrical portion and the lower cylindrical portion and faces upward. A housing step portion having an enlarged diameter is provided, and a cross-sectional shape of an inner edge of the housing step portion by a surface including the central axis is a substantially arc shape.

  The invention according to claim 8 is the fluid dynamic pressure bearing mechanism according to claim 7, wherein the upper cylindrical portion, the housing stepped portion and the lower cylindrical portion are made of a plate-shaped or cylindrical press. It is formed by processing.

  A ninth aspect of the present invention is an electric motor having the fluid dynamic pressure bearing mechanism according to any one of the first to eighth aspects, a field magnet attached to the upper end of the shaft. A rotor portion and a stator portion having an armature that is fixed to the fluid dynamic pressure bearing mechanism and faces the field magnet.

  The invention according to claim 10 is a method of manufacturing a fluid dynamic pressure bearing mechanism used for an electric motor, comprising: a) covering an upper portion of a cylindrical sleeve with an upper surface of the sleeve and an upper portion of an outer surface; Press-fitting an upper cap having an opening into the upper cap; and b) attaching an upper cylindrical portion that surrounds the outer surface of the upper cap and forms a gap between the outer cap and the upper cap to the sleeve. The inner side surface of the upper cylindrical portion has a first step portion that is recessed radially outward from the inner side surface toward the upper side, and the outer side surface of the upper cap extends from the outer side surface toward the upper side. A second stepped portion that is recessed inward in the radial direction, and in the step b), the upper end of the upper cylindrical portion and the upper surface of the upper cap are brought into contact with one jig and the first step in the central axis direction The relative position of the second step portion with respect to one step portion Having a constant to step.

  Invention of Claim 11 is a manufacturing method of the fluid dynamic pressure bearing mechanism of Claim 10, Comprising: The upper side of the said 1st level | step-difference part of the said upper cylindrical part, and the said 2nd level | step-difference part of the said upper cap The method further includes the step of applying an oil repellent on the upper side.

  The invention according to claim 12 is the method of manufacturing a fluid dynamic bearing mechanism according to claim 10 or 11, wherein in the step b), the upper end of the upper cylindrical portion and the upper surface of the upper cap Abuts against a plane perpendicular to the central axis of the jig.

  A thirteenth aspect of the invention is a method of manufacturing a fluid dynamic bearing mechanism according to any one of the tenth to twelfth aspects, wherein the upper cylindrical portion covers a lower portion of the outer surface of the sleeve. Part of a sleeve housing having a cylindrical portion.

  The invention according to claim 14 is the method of manufacturing the fluid dynamic bearing mechanism according to claim 13, wherein the sleeve housing connects the upper cylindrical portion and the lower cylindrical portion and moves upward. A housing step portion whose diameter increases toward the surface, and a cross-sectional shape of an inner edge of the housing step portion by a surface including the central axis is a substantially arc shape, and in the step b), the upper cylindrical portion The sleeve is inserted into the sleeve housing toward the lower cylindrical portion.

  The invention according to claim 15 is a cylindrical sleeve, a shaft member inserted into the sleeve and having an upper end protruding from the sleeve, a shaft member positioned at the lower end of the shaft, and an outer surface of the sleeve A fluid dynamic bearing mechanism comprising: a cylindrical housing body having a lower cylindrical portion covering at least a lower portion thereof; and a bottomed cylindrical lower cap covering a lower surface of the thrust plate, wherein: Inserting the sleeve into the lower cylindrical portion of the housing body; b) inserting the shaft of the shaft member from the lower side of the sleeve so that the upper surface of the thrust plate contacts the lower surface of the sleeve; C) moving the shaft member relative to the sleeve so that the lower surface of the sleeve and the thrust plate A step of securing a thrust gap of a predetermined size between the upper surface of the housing and d) fitting the lower cap to a lower portion of the outer side surface of the housing body, and the inner bottom surface of the lower cap and the thrust A step of contacting the lower surface of the plate, and e) a step of fixing the lower cap to the housing body.

  According to a sixteenth aspect of the present invention, there is provided a cylindrical sleeve, a shaft member inserted into the sleeve and having an upper end protruding from the sleeve, a shaft member positioned at the lower end of the shaft, and an outer surface of the sleeve A fluid dynamic pressure bearing mechanism comprising: a lower cylindrical portion that covers at least a lower portion of the thrust plate; and a bottomed cylindrical sleeve housing having a bottom portion that covers a lower surface of the thrust plate, and a) of the shaft member Inserting the shaft from below the sleeve to bring the upper surface of the thrust plate into contact with the lower surface of the sleeve; b) moving the shaft member relative to the sleeve; Securing a thrust gap of a predetermined size between the upper surface of the thrust plate and the upper surface of the thrust plate; c) before Fitting the lower cylindrical portion of the sleeve housing to a lower portion of the outer side surface of the sleeve and bringing the inner bottom surface of the sleeve housing into contact with the lower surface of the thrust plate; and d) attaching the sleeve housing to the sleeve. A fixing step.

  According to the present invention, the oil repellent can be easily applied to an appropriate range using the first step portion and the second step portion. In the invention of claim 2, the lubricating oil is stabilized in the capillary seal portion. Can be held. In the inventions of claims 3, 10 and 12, the bearing mechanism can be easily assembled, and in the invention of claim 4, the lubricating oil can be easily applied to the stepped portion.

  In the inventions of claims 7 and 14, the sleeve can be easily inserted into the lower cylindrical portion, and in the invention of claim 8, the manufacturing cost of the fluid dynamic pressure bearing mechanism can be suppressed. In the inventions of claims 15 and 16, the width of the thrust gap can be easily determined, and the gap width can be reset before the lower cap is attached.

  FIG. 1 is a longitudinal sectional view showing an outer rotor type electric motor 1 (hereinafter referred to as “motor 1”) according to an embodiment of the present invention. The motor 1 is used as a drive source of a recording disk drive device. Is done. The motor 1 includes a rotor unit 11 that is a rotating assembly, a stator unit 12 that is a fixed assembly, and a fluid dynamic pressure bearing mechanism 2 that supports the rotor unit 11 rotatably with respect to the stator unit 12 (hereinafter referred to as “bearing mechanism”). 2 ”). In the following description, for convenience, the rotor part 11 side is described as the upper side and the stator part 12 side is the lower side along the central axis J1, but the central axis J1 does not necessarily coincide with the direction of gravity.

  The rotor unit 11 includes a substantially covered cylindrical rotor hub 111 to which the recording disk 13 is fixed, and a field magnet 112 attached to the rotor hub 111 and disposed around the central axis J1. The stator portion 12 includes a base bracket 121 that is a base portion having a hole formed in the center, and an armature 122 that is attached to the base bracket 121 around the hole portion and faces the field magnet 112. The armature 122 generates a rotational force (torque) around the central axis J1 between the armature 122 and the annular magnetic field magnet 112 magnetized. The bearing mechanism 2 is fixed to the hole of the base bracket 121 with a thermosetting adhesive.

  FIG. 2 is a longitudinal sectional view showing the bearing mechanism 2 that uses the fluid dynamic pressure of the motor 1. The bearing mechanism 2 has a cylindrical sleeve 21 centered on the central axis J1, a shaft 22 inserted into the sleeve 21, a lower end of the shaft 22, a thrust plate 23 facing the lower surface of the sleeve 21, and a lower surface of the thrust plate 23. And a bottomed cylindrical sleeve housing 24 that covers the outer surface of the sleeve 21, and an upper cap 25 that covers the upper surface of the sleeve 21 and the upper portion of the outer surface.

  In the sleeve housing 24, a bottomed cylindrical lower cap 242 that covers the lower outer surface of the housing main body 241 and the lower surface of the thrust plate 23 is fitted to the lower portion of the substantially cylindrical housing main body 241 that covers the outer surface of the sleeve 21. And fixed by bonding. The upper cap 25 has an opening 2511 into which the upper end of the shaft 22 protruding from the sleeve 21 is inserted, and the upper end of the shaft 22 is attached to the rotor portion 11 as shown in FIG. The part 12 is supported so as to be rotatable.

  3, 4 and 5 are a plan view, a longitudinal sectional view and a bottom view of the sleeve 21, respectively. The sleeve 21 has a plurality of upper surface grooves 2111 extending radially in the upper surface 211, a plurality of outer surface grooves 2121 extending in a direction parallel to the central axis J1 in the outer surface 212, and a spiral thrust dynamic pressure groove 2131 in the lower surface 213. Have. The upper surface groove 2111 is located at three positions at equal intervals in the circumferential direction, and the outer surface groove 2121 is formed at the same circumferential position as the position of the upper surface groove 2111. The depth of the upper surface groove 2111 is smaller than the axial width of the chamfered portion provided on the outer edge of the upper surface 211 and the chamfered portion provided on the inner edge of the upper surface 211, and the depth of the outer surface groove 2121 is the outer edge of the upper surface 211. It is smaller than the width of the chamfered portion in the radial direction. The sleeve 21 is a porous sintered metal body, and an upper surface groove 2111, an outer surface groove 2121 and a thrust dynamic pressure groove 2131 are formed during press molding.

  6 is a front view of the shaft 22. The shaft 22 includes a radial dynamic pressure groove 221 formed on the outer surface, an annular recess 222 centered on the central axis J1 formed above the radial dynamic pressure groove 221, and The lower end surface has a female screw 223 along the central axis J1. The radial dynamic pressure grooves 221 are formed at two locations separated in the axial direction, and the lubricating oil fills the radial gap 261 (see FIG. 2) between the inner surface of the sleeve 21 and the outer surface of the shaft 22 by the rotation of the shaft 22. As a result, a radial dynamic pressure, which is a supporting force for supporting the shaft 22, is induced, whereby the shaft 22 is supported by the sleeve 21 in the radial direction in a non-contact manner. The upper groove (collection) 2211 and the lower groove (collection) 2212 of the radial dynamic pressure groove 221 each have a herringbone shape, and the upper straight portion of the groove 2211 is longer than the lower straight portion. Simultaneously with the pressure, a dynamic pressure is generated to send the lubricating oil downward in the radial gap 261. In the groove 2212, the lengths of the upper and lower linear portions are equal, and only radial dynamic pressure is generated. The annular recess 222 has a tapered surface 2221 on the lower side, and the tapered surface 2221 is inclined so that the outer diameter of the shaft 22 decreases from the lower side to the upper side.

  7 and 8 are a front view and a bottom view of the thrust plate 23. The thrust plate 23 has a disk-shaped plate portion 231 and a male screw 232 protruding upward from the center of the plate portion 231 as shown in FIG. And is fixed to the lower end portion of the shaft 22 by screwing with a female screw 223 (see FIG. 6) of the shaft 22. Further, as shown in FIG. 8, the plate portion 231 has a spiral-shaped thrust dynamic pressure groove 2311 (shown with parallel oblique lines) on the lower surface.

  As shown in FIG. 2, when the shaft 22 and the thrust plate 23 rotate, the lubricating oil flows from the radial gap 261 into the first thrust gap 262 between the lower surface 213 of the sleeve 21 and the upper surface of the thrust plate 23. On the other hand, a thrust dynamic pressure is generated in the first thrust gap 262 by the thrust dynamic pressure groove 2131 (see FIG. 5) on the lower surface 213. The second thrust gap 263 between the thrust plate 23 and the lower cap 242 is also filled with lubricating oil, and the second thrust gap 263 is formed by a thrust dynamic pressure groove 2311 (see FIG. 8) on the lower surface of the thrust plate 23. Thrust dynamic pressure is generated, and the shaft 22 is supported in the thrust direction by the thrust dynamic pressure of the first thrust gap 262 and the second thrust gap 263. Further, a gap 264 that communicates the first thrust gap 262 and the second thrust gap 263 is provided between the outer side surface of the thrust plate 23 and the inner side surface and the inner bottom surface of the sleeve housing 24, and is filled with lubricating oil. Yes.

  FIG. 9 is a longitudinal sectional view of a substantially cylindrical housing body 241 of the sleeve housing 24. As shown in FIG. 2, the housing main body 241 has a cylindrical portion 2411 that is a lower cylindrical portion that covers the lower portion of the outer surface of the sleeve 21, and an upper portion that is an upper cylindrical portion that surrounds the outer surface of the upper cap 25 and a lower portion. An annular taper portion 2412 whose diameter gradually increases from the top toward the top. The inner diameter of the lower end portion of the annular tapered portion 2412 is larger than the inner diameter of the cylindrical portion 2411, and the annular tapered portion 2412 and the cylindrical portion 2411 connect between the annular tapered portion 2412 and the cylindrical portion 2411 and move upward. A housing step portion 2413 having an increased diameter is formed. The housing stepped portion 2413 has a cross-sectional shape of an inner edge formed by a surface including the central axis J1 having a substantially arc shape (hereinafter referred to as “R shape”), and the width and the central axis of the R shape in the direction of the central axis J1. The width in the direction perpendicular to J1 is larger than the width in the direction of the central axis J1 and the width in the direction perpendicular to the central axis J1 of the chamfered portion (see FIGS. 4 and 5) provided on the outer edge of the lower surface 213 of the sleeve 21, respectively. large. The R shape is formed by bending when the housing main body 241 (that is, the annular tapered portion 2412, the housing stepped portion 2413, and the cylindrical portion 2411) is formed by pressing a plate-shaped or cylindrical material.

  10 is a plan view of the lower cap 242 of the sleeve housing 24, and FIG. 11 is a cross-sectional view at a position indicated by an arrow A in FIG. The lower cap 242 has a disk-shaped bottom portion 2421 and a cylindrical side portion 2422. The lower cap 242 is fitted into the cylindrical portion 2411 (see FIG. 9) of the housing main body 241 from below and bonded with an adhesive. The The bottom portion 2421 has a convex portion 2423 that is annular around the central axis J1 and slightly protrudes upward, and the convex portion 2423 locally forms a gap between the lower surface of the thrust plate 23 as shown in FIG. The thrust dynamic pressure in the second thrust gap 263 is increased by narrowing it to ˜.

  As shown in FIG. 11, narrow grooves 2424 extending in the circumferential direction for holding the adhesive are provided at two locations in the axial direction on the inner surface of the side portion 2422, and projecting upward at the upper end portion of the side portion 2422. Three claw portions 2425 are provided at equal intervals in the circumferential direction. As shown in FIG. 2, the sleeve 21 is press-fitted and fixed to the inner surface of the cylindrical portion 2411 of the housing body 241, and the outer surface groove 2121 (see FIG. 3) of the sleeve 21 and the outer surface of the sleeve 21 and the cylindrical portion 2411. A flow path 265 for guiding the lubricating oil from the first thrust gap 262 upward (hereinafter referred to as “outer lower flow path 265”) is formed between the inner side surface and the inner side surface.

  12 is a bottom view of the substantially cap-shaped cylindrical upper cap 25, and FIG. 13 is a cross-sectional view at a position indicated by an arrow B in FIG. The upper cap 25 has an annular and plate-like upper portion 251 and a cylindrical portion 252 extending downward from the outer periphery of the upper portion 251, and as shown in FIG. 2, the upper end of the shaft 22 is inserted into the central circular opening 2511, The upper portion of the sleeve 21 is press-fitted into the cylindrical portion 252. The inner diameter of the opening 2511 is larger than the outer diameter of the shaft 22, and the inner side surface 2513 of the opening 2511 is a cylindrical surface parallel to the central axis J1 as shown in FIG.

  FIG. 14 is an enlarged view showing the upper part of the bearing mechanism 2. As shown in FIGS. 12 to 14, convex portions 2512 that are four circular protrusions are provided at equal intervals in the circumferential direction on the lower surface of the upper portion 251 of the upper cap 25. As shown in FIG. Abuts on the upper surface 211 of the sleeve 21. As shown in FIGS. 12 and 13, four concave portions 2521 extending in parallel to the central axis J <b> 1 from the lower end portion to the lower surface of the upper portion 251 are provided on the inner surface of the cylindrical portion 252 at equal intervals in the circumferential direction. Is located in the middle of the two convex portions 2512 in the circumferential direction. The circumferential width of the convex portion 2512 of the upper portion 251 is made larger than the circumferential width of the upper surface groove 2111 of the sleeve 21 shown in FIG. 3, thereby preventing the convex portion 2512 from fitting into the upper surface groove 2111. . The concave portion 2521 is a groove facing the outer surface 212 of the sleeve 21, and the circumferential width of the portion between the adjacent concave portions 2521 is made larger than the width of the outer surface groove 2121 of the sleeve 21 shown in FIG. The portion between the recesses 2521 is prevented from fitting into the outer surface groove 2121.

  As shown in FIG. 14, the outer upper surface 212 is formed between the outer surface 212 of the sleeve 21 and the inner surface of the cylindrical portion 252 of the upper cap 25 by the outer surface groove 2121 of the sleeve 21 and the recess 2521 on the inner surface of the upper cap 25. A flow path 266 is formed, and a gap 2514 is provided between the upper surface 211 of the sleeve 21 and the lower surface of the upper portion 251 of the upper cap 25, and the convex portion 2512 of the upper cap 25 abuts against the upper surface 211 of the sleeve 21. The upper flow path 267 is formed by the upper surface groove 2111 of the sleeve 21. Lubricating oil flows from the outer lower channel 265 into the outer upper channel 266, flows upward, flows into the upper channel 267, and returns to the central radial gap 261.

  As shown in FIG. 13, the outer surface of the lower end portion of the cylindrical portion 252 is a cylindrical cut surface 2522 formed at the time of cutting by the press at the time of manufacturing the upper cap 25, and the central axis J1 The diameter of the parallel cut surface 2522 is slightly larger than the outer diameter of the cylindrical portion 252 above the cut surface 2522. Further, the lower portion of the inner side surface of the cylindrical portion 252 has an R shape with a substantially arc-shaped cross section (depending on the surface including the central axis J1). The width of the R shape in the direction of the central axis J1 and the direction perpendicular to the central axis J1 Is made larger than the width in the direction of the central axis J1 and the width in the direction perpendicular to the central axis J1 of the chamfered portion (see FIGS. 3 and 4) provided at the outer edge of the upper surface 211 of the sleeve 21.

  As shown in FIG. 2, in the bearing mechanism 2, a circulation path 26 is formed by the radial gap 261, the first thrust gap 262, the outer lower flow path 265, the outer upper flow path 266, and the upper flow path 267, and the lubricating oil circulates. The passage 26 is continuously filled and circulated by dynamic pressure generated as the shaft 22 rotates. On the other hand, the outer surface of the upper cap 25 is provided with a first taper seal portion 271 which is a capillary seal portion in which the lubricating oil is held by surface tension in the gap between the annular taper portion 2412 shown in FIG. A second taper seal portion 272 that is a capillary seal portion is also provided on the inner periphery of the cap 25, and lubricating oil is held by these taper seal portions 271 and 272. Here, the lubricant flows into the outer lower flow path 265 of the circulation path 26 from the first thrust gap 262 that is a dynamic pressure gap communicating with the lower portion of the radial gap as the fluid dynamic pressure is generated when the shaft 22 rotates. In addition, the outer upper flow path 266 that serves as a flow path (first flow path 26a) that connects the first thrust gap 262 and the first taper seal portion 271 and is a gap between the sleeve 21 and the upper cap 25. The upper flow path 267 serves as a flow path (second flow path 26b) through which the first tapered seal portion 271 communicates with the upper portion of the radial gap 261 and lubricating oil flows from the outer lower flow path 265.

  FIG. 15 is an enlarged view showing the first taper seal portion 271 and the second taper seal portion 272. The first taper seal portion 271 has a tapered gap 2712 between the inner surface 2414 of the annular taper portion 2412 of the housing body 241 and the outer surface of the cylindrical portion 252 of the upper cap 25 located inside the annular taper portion 2412. (Hereinafter referred to as “first taper gap 2712”). The first taper gap 2712 gradually expands upward. In the first taper seal portion 271, a capillary force is generated downward by the first taper gap 2712, and the first interface 2711 is located at a position that balances the internal pressure. A capillary seal portion is formed to hold the lubricating oil. An oil repellent is applied to the upper part of the first taper gap 2712 to prevent leakage of the lubricating oil.

  The second taper seal portion 272 has a tapered gap 2722 (hereinafter, “second taper”) formed by the taper surface 2221 of the shaft 22 and the inner surface 2513 of the opening 2511 (see FIG. 13) of the upper cap 25 above the radial gap 261. It is referred to as a gap 2722 "). The second taper gap 2722 gradually expands upward. In the second taper seal portion 272, a capillary force is generated downward by the second taper gap 2722, and the second interface 2721 is located at a position that balances the internal pressure. A capillary seal portion that is formed and holds lubricating oil continuous from the radial gap 261 is formed. An oil repellent agent is applied to the upper side of the tapered surface 2221 of the shaft 22 and the upper surface of the upper cap 25 to prevent leakage of the lubricating oil.

  FIG. 16 is an enlarged view showing the upper part of the bearing mechanism 2, and shows the upper part 251 of the upper cap 25 and the upper end part of the annular taper part 2412 that is a part of the sleeve housing 24 (that is, the upper part of the first taper seal part 271). Show. The inner surface 2414 of the annular taper portion 2412 is recessed radially outward from the inner surface toward the upper side in the central axis J1 direction (and the upper portion of the inner surface 2414) from the lubricating oil interface 2711. A first stepped portion 2417 whose diameter increases toward the surface is formed, and an upper portion of the first stepped portion 2417 has an R shape in which a section including the central axis J1 is substantially arc-shaped, An R portion 2418 that connects the portion 2417 and the upper end surface of the annular tapered portion 2412 with a smooth curved surface is formed. A region from the first step portion 2417 to the upper end surface of the annular taper portion 2412 is an oil repellent region, and an oil repellent film is formed by applying a fluoropolymer or the like. In addition, the outer surface of the upper cap 25 is recessed radially inward from the outer surface toward the upper side in the central axis J1 direction (and the upper portion of the outer surface) from the lubricant interface 2711, that is, upward. A second stepped portion 2515 whose diameter decreases toward the bottom is formed, and the upper portion of the second stepped portion 2515 is also R-shaped, and the second stepped portion 2515 and the upper end surface of the upper cap 25 are smooth curved surfaces. An R portion 2516 to be connected is provided, and a region from the second step portion 2515 to the upper surface of the upper cap 25 is an oil repellent region, and an oil repellent film is formed.

  The positions of the upper end of the annular tapered portion 2412 and the upper surface of the upper cap 25 in the direction of the central axis J1 are substantially the same, and the axial height from the first stepped portion 2417 to the upper end surface of the housing body 241; The height in the axial direction from the second step portion 2515 to the upper surface of the upper cap 25 is equalized as indicated by h in FIG. Therefore, the positions of the first stepped portion 2417 and the second stepped portion 2515 in the direction of the central axis J1 are substantially the same, and the first interface 2711 has risen to the first stepped portion 2417 and the second stepped portion 2515. However, the interfacial tension can be maintained in a well-balanced manner, and the lubricating oil can be stably held by the taper seal portion 271. The first stepped portion 2417 and the R portion 2418, and the second stepped portion 2515 and the R portion 2516, when the housing body 241 and the upper cap 25 are formed by pressing, respectively, are pressed and bent during pressing. Can be easily formed. Thereby, the manufacturing cost of the bearing mechanism 2 can be suppressed.

  Next, a method for manufacturing the bearing mechanism 2 will be described. FIG. 17 is a view showing a flow of manufacturing the bearing mechanism 2, and FIGS. 18 to 25 are views showing manufacturing steps of the bearing mechanism 2. For convenience of explanation, FIGS. 18 to 25 show the bearing mechanism 2 in the same direction as FIG. 16, but the upper side is the lower side in the gravity direction in the actual work process.

  First, before assembling, an oil repellent region composed of an R portion 2418 located above the first step portion 2417 of the annular taper portion 2412 and the upper end surface of the annular taper portion 2412 shown in FIG. The oil repellent agent is applied to the oil repellent region formed by the R portion 2516 located above the second step portion 2515 and the upper surface of the upper cap 25. When the oil repellent is applied, the operation can be performed easily and accurately by performing the work using the first step portion 2417 and the second step portion 2515 as marks. Further, the first step portion 2417 and the second step portion 2515 prevent the oil repellent agent from flowing into the first taper seal portion 271. The applied oil repellent is baked by heating (step S11).

  Next, as shown in FIG. 18, the sleeve 21 is held by the jig 92 while the upper surface 211 of the sleeve 21 is opposed to the lower surface of the upper portion 251 of the upper cap 25, and the upper cap 25 is held by the jig 91. The sleeve 21 moves upward in the axial direction (actually downward in the direction of gravity), and the upper portion of the sleeve 21 is press-fitted into the upper cap 25. At this time, as shown in FIG. 19, the sleeve 21 is inserted until the upper surface 211 of the sleeve 21 comes into contact with the convex portion 2512 provided on the lower surface of the upper portion 251 of the upper cap 25 (step S12).

  Thereafter, as shown in FIGS. 20 and 21, the housing main body 241 is placed on the lower side of the sleeve 21 and the upper cap 25 by a jig 93 having an opening at the center while the annular taper portion 2412 is opposed to the lower surface 213 of the sleeve 21. The sleeve 21 is inserted into the cylindrical portion 2411 from the annular tapered portion 2412 toward the cylindrical portion 2411. At this time, the sleeve 21 can be easily inserted into the cylindrical portion 2411 by the R shape provided on the inner surface of the housing step portion 2413 connecting the annular tapered portion 2412 and the cylindrical portion 2411 of the housing body 241. It is possible. Further, the outer surface side of the housing stepped portion 2413 contacts and is supported by the jig 93, so that the sleeve 21 can be stably inserted into the cylindrical portion 2411.

  As shown in FIG. 21, the upper surface of the upper cap 25 is in contact with a surface 911 perpendicular to the central axis of the jig 91 (which coincides with the central axis of the bearing mechanism 2 during assembly), and the cylindrical portion of the sleeve 21. The insertion into 2411 is performed until the upper end portion of the annular taper portion 2412 contacts the surface 911. As shown in FIG. 16, since the heights of the upper portions of the stepped portions 2417 and 2515 are equal, the first stepped portion 2417 and the second stepped portion are brought into contact with the surface 911 by the annular tapered portion 2412 and the upper cap 25 contacting each other. The relative position in the central axis direction with respect to 2515 is determined, and the heights substantially coincide. With the above operation, the attachment of the housing main body 241 having the annular tapered portion 2412 to the sleeve 21 is completed (step S13). Here, since the inner diameter of the sleeve 21 is distorted by press-fitting the sleeve 21 into the housing main body 241, the assembly shown in FIG. 21 is transferred to a device (not shown) that applies plastic deformation accompanying cutting to the inner surface of the sleeve 21. Thus, the inner diameter of the sleeve 21 is adjusted.

  When the inner diameter of the sleeve 21 is adjusted, as shown in FIG. 22, the assembly of the housing body 241, the sleeve 21 and the upper cap 25 is supported by a jig 94 having an opening in the center, and the thrust plate 23 is fixed to the lower end. The shaft 22 thus inserted is inserted from the lower portion of the sleeve 21, and the upper surface of the thrust plate 23 contacts the lower surface 213 of the sleeve 21 as shown in FIG. 23 (step S14).

  Next, as shown in FIGS. 23 and 24, the contact member 95 comes into contact with the tip of the shaft 22 (ie, the lower part in the direction of gravity) from the opening of the jig 94 and pushes the shaft 22 toward the thrust plate 23 side. Thus, the shaft member which is the shaft 22 and the thrust plate 23 moves relative to the sleeve 21, and a thrust gap 268 (hereinafter referred to as “hereinafter,“ thrust gap ”268) having a predetermined size between the thrust plate 23 and the lower surface 213 of the sleeve 21. A gap 268 ") is ensured. In this state, the position of the contact member 95 is fixed, and the relative position of the thrust plate 23 with respect to the sleeve 21 is fixed. The width of the gap 268 is the combined width of the first thrust gap 262 and the second thrust gap 263 shown in FIG. 2 (step S15).

  Thereafter, as shown in FIG. 25, the lower cap 242 is fitted from the lower surface side of the thrust plate 23 to the lower portion of the outer surface of the cylindrical portion 2411 of the housing body 241, and the inner bottom surface of the lower cap 242 contacts the lower surface of the thrust plate 23. To do. An anaerobic adhesive is applied to the inner surface of the lower cap 242 in advance, and the cylindrical portion 2411 is inserted into the lower cap 242 so that the space between the outer surface of the cylindrical portion 2411 and the inner surface of the lower cap 242 is reduced. Adhesive spreads. In this state, the lower cap 242 is held until the adhesive is solidified, and is fixed to the cylindrical portion 2411 (step S16).

  As described above, in the bearing mechanism 2, the oil repellent agent can be easily applied to an appropriate range using the first step portion 2417 and the second step portion 2515 as shown in FIG. Further, the R portion 2418 and the R portion 2516 can easily apply the lubricating oil to the stepped portion by utilizing the action of spreading the oil repellent agent itself. Further, the upper end portion of the annular taper portion 2412 and the upper surface of the upper cap 25 are brought into contact with one jig 91 so that their positions in the central axis direction coincide with each other, whereby the first step portion 2417 and the second step portion. Positioning with 2515 can be easily performed, and the assembly of the bearing mechanism 2 can be easily performed. On the other hand, according to the assembling method shown in FIGS. 22 to 25, the width of the thrust gap can be easily determined without being influenced by the shape accuracy of each part. Even if the gap 268 is set incorrectly, the lower cap The gap width can be reset before attaching 242. As a result, it is possible to prevent a load from being applied to the assembled bearing mechanism as in the case of adjustment after assembly, and to improve the reliability of the bearing mechanism.

  In the bearing mechanism 2, the sleeve housing 24 is configured by parts formed by press working, and the first step portion 2417 and the second step portion 2515 are formed by using press work. The manufacturing cost can be greatly reduced as compared with the case where the overall shape of the sleeve housing and the stepped portion are formed.

  FIG. 26 is a longitudinal sectional view showing another example of a bearing mechanism used in the motor 1. The bearing mechanism 2a shown in FIG. 26 differs from the bearing mechanism 2 shown in FIG. 2 in that it has a sleeve housing 24a formed integrally instead of the sleeve housing 24 constituted by two members. In addition, the sleeve housing 24a and the upper cap 25 are provided with the first step portion 2417 and the second step portion 2515 similar to those in FIG. The bearing mechanism 2 a includes a cylindrical sleeve 21, an upper cap 25 that is press-fitted into the upper portion of the sleeve 21, a shaft 22 that is inserted into the sleeve 21 and has an upper end protruding from the sleeve 21, and a thrust plate 23 that is positioned at the lower end of the shaft 22. A shaft member having a bottom, and a cylindrical sleeve housing 24a having a bottom, the sleeve housing 24a being an upper tapered cylindrical portion 2412, a cylindrical portion 2411a being a lower cylindrical portion covering the outer surface of the sleeve 21, and A bottom portion 2421 a that covers the lower surface of the thrust plate 23 is provided.

  FIG. 27 is a view showing a flow of manufacturing the bearing mechanism 2a, and FIGS. 28 to 31 are longitudinal sectional views showing a state of manufacturing the bearing mechanism 2a. In assembling the bearing mechanism 2a, first, similarly to step S11 of FIG. 17, an R portion 2418 (see FIG. 16) located above the first step portion 2417 of the annular taper portion 2412 and an upper end surface of the annular taper portion 2412 An oil repellent is applied to the oil repellent region composed of the above and the oil repellent region composed of the R portion 2516 located above the second step portion 2515 of the upper cap 25 and the upper surface of the upper cap 25, and the oil repellent is fired by heating. (Step S21). Next, as in the case of the bearing mechanism 2, the operation shown in FIGS. 18 and 19 is performed, and the sleeve 21 until the upper surface 211 of the sleeve 21 comes into contact with the convex portion 2512 provided on the lower surface of the upper portion 251 of the upper cap 25. 21 is inserted (step S22), and then, as shown in FIG. 28, the assembly of the sleeve 21 and the upper cap 25 is supported by a jig 94 having an opening in the center, and the shaft with the thrust plate 23 fixed to the lower end. 22 is inserted from the lower portion of the sleeve 21, and the upper surface of the thrust plate 23 contacts the lower surface 213 of the sleeve 21 as shown in FIG. 29 (step S23).

  When the shaft 22 is inserted into the sleeve 21, as shown in FIGS. 29 and 30, the contact member 95 comes into contact with the tip end portion of the shaft 22 (ie, the lower portion in the direction of gravity) from the opening of the jig 94. By pushing 22 toward the thrust plate 23, the shaft 22 and the shaft member which is the thrust plate 23 move relative to the sleeve 21, and a predetermined size is provided between the thrust plate 23 and the lower surface 213 of the sleeve 21. The gap 268 is secured. In this state, the position of the contact member 95 is fixed, and the relative position of the thrust plate 23 with respect to the sleeve 21 is fixed (step S24). Thereafter, as shown in FIG. 31, the sleeve housing 24 a is externally fitted to the lower portion of the outer surface of the sleeve 21 from the thrust plate 23 side until the inner bottom surface of the bottom portion 2421 a of the sleeve housing 24 a contacts the lower surface of the thrust plate 23. As a result, the anaerobic adhesive previously applied to the inner surface of the cylindrical portion 2411a spreads between the outer surface of the sleeve 21 and the inner surface of the cylindrical portion 2411a and is held until the adhesive is solidified. Is fixed to the sleeve 21 (step S25).

  As described above, by the method shown in FIGS. 28 to 31, the width of the thrust gap 268 can be easily determined even in the assembly of the bearing mechanism 2a, and the gap width before the sleeve housing 24a is attached. It can be reset. Similarly to the bearing mechanism 2 shown in FIG. 16, the lube repellant is easily applied to an appropriate range by using the first step portion 2417 of the annular taper portion 2412 and the second step portion 2515 of the upper cap 25. be able to.

  FIG. 32 is a view showing still another example of the bearing mechanism. The bearing mechanism 2b shown in FIG. 32 includes a substantially cylindrical sleeve 30, an annular tapered portion 2412a which is an upper cylindrical portion attached to the sleeve 30, and a sleeve. A shaft-like lower cap 242a that closes the lower portion of the shaft 30 is inserted, and the shaft 22, the thrust plate 23, and the upper cap 25 that are inserted into the sleeve 30 and project the upper end upward as in the bearing mechanism 2 shown in FIG. Is further provided.

  The sleeve 30 has a small diameter at the upper portion, and an annular convex portion 301 that protrudes downward is provided at the outer peripheral edge of the lower surface. A shaft 22 is inserted into the sleeve 30 from below, and a thrust plate 23 attached to the lower end of the shaft 22 is positioned inside the annular convex portion 301. An upper cap 25 that covers the upper surface and the outer surface of the sleeve 30 is press-fitted into the upper portion of the sleeve 30, and an annular taper whose diameter gradually increases toward the outer periphery of the step portion provided on the outer surface of the sleeve 30. The part 2412a is fixed. As a result, a first taper seal portion 271 similar to that shown in FIG. 2 is formed on the outer periphery of the sleeve 30, and a second taper seal portion 272 is formed around the shaft 22. Further, the lower cap 242a is fixed in the annular convex portion 301 on the lower surface of the sleeve 30, whereby the lower surface side of the thrust plate 23 is closed.

  In the sleeve 30, a communication path extending in parallel to the central axis J <b> 1 direction from the lower surface toward the stepped portion is provided, whereby the first thrust gap 262 between the lower surface of the sleeve 30 and the upper surface of the thrust plate 23 is provided. The lubricating oil is guided to the lower part of the one taper seal portion 271. That is, in the bearing mechanism 2b of FIG. 31, the lubricating oil flows from the first thrust gap 262 as the fluid dynamic pressure is generated when the shaft 22 rotates, and the first thrust gap 262 and the first taper seal portion 271 communicate with each other. A first flow path 26 a is formed in the sleeve 30. The second flow path 26b in which lubricating oil flows in from the first flow path 26a and connects the first taper seal portion 271 and the second taper seal portion 272 is the same as the outer upper flow path 266 and the upper flow path 267 in FIG. Formed.

  In the bearing mechanism 2b as well, as in the assembly process of the bearing mechanism 2 shown in FIGS. 20 and 21, first, the opening of the annular tapered portion 2412a is opposed to the lower surface of the sleeve 30, and the upper cap 25 is in contact with it. The annular tapered portion 2412a is inserted into the sleeve 30 until the upper end surface of the annular tapered portion 2412a comes into contact with the surface of the tool. As a result, as in the case of FIG. 16, the positions of the upper end of the annular taper portion 2412a and the upper surface of the upper cap 25 in the axial direction coincide with each other, and the first step portion 2417 provided on the annular taper portion 2412a and the upper cap 25 The positions of the two step portions 2515 (see FIG. 16) in the central axis direction also substantially coincide. As a result, also in the bearing mechanism 2b, the lubricating oil is stably held by the first taper seal portion 271 in FIG.

  FIG. 33 is a view showing still another example of the bearing mechanism. Compared with the bearing mechanism 2b of FIG. 32, the bearing mechanism 2c of FIG. 33 is formed on the upper portion of the sleeve 31 from the vicinity of the lower portion of the first taper seal portion 271. The difference is that a pore 311 that penetrates to the lower part of the second taper seal portion 272 is provided, and the flow path between the upper cap 25 and the sleeve 21 is omitted. Other configurations are the same as those in FIG. 32, and are denoted by the same reference numerals.

  In the bearing mechanism 2c of FIG. 33, in the same manner as the bearing mechanism 2b of FIG. 32, the fluid dynamic pressure is generated during the rotation of the shaft 22, and the first thrust gap 262 between the sleeve 31 and the thrust plate 23 enters the sleeve 31. Lubricating oil flows into the formed first flow path 26a, and the lubricating oil is removed from the radial gap by the pores 311 that are the second flow paths 26b that connect the first taper seal portion 271 and the second taper seal portion 272. Returned to the top.

  Also in the assembly of the bearing mechanism 2c, the first stepped portion 2417 and the second stepped portion 2417 and the second stepped portion 2412 are formed by substantially matching the positions of the upper end of the annular tapered portion 2412a and the upper surface of the upper cap 25 in the central axis direction, as in the bearing mechanism 2b of FIG. The position of the stepped portion 2515 (see FIG. 16) in the central axis direction can be easily made substantially coincident, and the lubricating oil can be stably held in the first taper seal portion 271.

  FIG. 34 is a view showing still another example of the bearing mechanism, and shows an enlarged upper part of the bearing mechanism. A bearing mechanism 2d shown in FIG. 34 replaces the first step portion 2417 and the second step portion 2515 of the bearing mechanism 2 shown in FIG. 16, and a first groove 2417a extending in the circumferential direction above the inner side surface 2414 of the annular taper portion 2412. Another difference is that a second groove 2515a extending in the circumferential direction is provided at the upper part of the outer surface of the upper cap 25. The first groove 2417a and the second groove 2515a are formed by cutting or pressing.

  In the bearing mechanism 2d of FIG. 34, the lower edge of the first groove 2417a is radially upward from the inner side surface 2414 upward in the central axis direction above the lubricant interface 2711 on the inner side surface 2414 of the annular taper portion 2412. It is a first step portion that is recessed outward (that is, the diameter increases upward), and the upper portion of the first groove 2417a has a substantially arc-shaped cross section with a plane including the central axis. An R portion 2418 that is shaped and connects the first groove 2417a and the upper end surface of the annular tapered portion 2412 with a smooth curved surface is formed. An oil repellent film is formed on the surface from the first groove 2417a (that is, the first stepped portion) to the upper end surface of the annular tapered portion 2412 by applying a fluoropolymer or the like.

  Further, the lower edge of the second groove 2515a is also recessed inward in the radial direction from the outer surface toward the upper side in the central axis direction above the lubricant interface 2711 on the outer surface of the upper cap 25 (that is, The second step portion has a diameter that decreases toward the top), and the upper portion of the second groove 2515a has an R shape, and the second groove 2515a and the upper end surface of the upper cap 25 have a smooth curved surface. An R portion 2516 to be connected is provided, and an oil repellent film is formed on the surface from the second groove 2515a (that is, the second step portion) to the upper surface of the upper cap 25.

  Similarly to the bearing mechanism 2 of FIG. 16, in the bearing mechanism 2d of FIG. 34, the positions of the upper end of the annular tapered portion 2412 and the upper surface of the upper cap 25 in the central axis direction are substantially the same, and the first step portion and the second step portion. The positions in the direction of the central axis also substantially coincide with each other, and even when the first interface 2711 rises to the first step portion and the second step portion, the interface tension can be maintained in a balanced manner, and the taper seal portion 271 is maintained. The lubricating oil can be stably held at. Further, the lubricating oil can be easily applied to the stepped portion only by applying the lubricating oil to the upper end surface of the annular tapered portion 2412 and the upper surface of the upper cap 25 by the R portion 2418 and the R portion 2516. Note that the oil repellent may be applied only to the inside of the groove.

  FIG. 35 is a longitudinal sectional view showing still another example of the bearing mechanism. The bearing mechanism 2e shown in FIG. 35 is different from the bearing mechanism 2a shown in FIG. 26 in that the thrust plate 23 is omitted and the lower end of the shaft 22 contacts the plate 28 attached to the inner bottom surface of the sleeve housing 24a. To do. Further, in the second taper seal portion 272, an inclined surface is provided on the inner side surface of the opening of the upper cap 25. The other structure is the same as that of the bearing mechanism 2a of FIG.

  The lower end portion of the shaft 22 has a spherical shape, and a pivot bearing that supports the shaft 22 in the thrust direction is configured by making point contact with the upper surface of the plate 28 made of a wear-resistant material. . In the bearing mechanism 2e, as the fluid dynamic pressure is generated when the shaft 22 rotates, the lubricating oil flows into the gap 269 between the lower surface of the sleeve 21 and the upper surface of the plate 28 from the lower portion of the radial gap. The outer lower flow path formed by the groove and the gap 269 serve as the first flow path 26a that connects the radial gap 261 and the first taper seal portion 271. The first taper seal portion 271 and the second taper seal portion 272 are connected to each other. The communicating second flow path 26b is provided between the upper cap 25 and the sleeve 21 in the same manner as the bearing mechanism 2a in FIG. 26 (or the bearing mechanism 2 in FIG. 2). Also in the bearing mechanism 2e of FIG. 35, the oil repellent is easily applied to an appropriate range using the first step portion 2417 of the annular taper portion 2412 and the second step portion 2515 of the upper cap 25 as shown in FIG. be able to.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the said embodiment, A various change is possible.

  For example, the upper part of the first step part 2417 and the upper part of the second step part 2515 shown in FIG. 16 are not limited to an R shape having a substantially arc-shaped cross section, and the surface extends linearly from the step part to the upper end surface in the cross section. It may be. 20 and 21, the surface 911 of the jig 91 on which the upper cap 25 and the annular taper portion 2412 abut is not limited to a plane, and the center axis direction between the upper surface of the upper cap 25 and the upper end of the annular taper portion 2412 is designed. If these positions are different, they may abut on individual surfaces of the jig 91.

  Further, the formation of the gap between the lower surface of the sleeve 21 and the thrust plate 23 in the assembly process shown in FIGS. 22 to 24 is a method of moving the shaft 22 while fixing the sleeve 21, the upper cap 25 and the housing body 241. Without limitation, the shaft 22 may be fixed and the sleeve 21, the upper cap 25, and the housing body 241 may be moved.

  In the radial gap 261 shown in FIG. 2, a radial dynamic pressure groove may be formed on the inner surface of the sleeve 21 instead of the radial dynamic pressure groove 221 (see FIG. 6) formed on the shaft 22. Further, in the first thrust gap 262, a thrust dynamic pressure groove may be formed on the upper surface of the thrust plate 23 instead of the thrust dynamic pressure groove 2131 (see FIG. 5) on the lower surface 213 of the sleeve 21, and the second thrust gap 263 is formed. The thrust dynamic pressure grooves may be formed on the inner bottom surface of the sleeve housing 24 instead of the thrust dynamic pressure grooves 2311 (see FIG. 8) on the lower surface of the thrust plate 23. The shaft 22 and the thrust plate 23 may be formed of a single member.

  The annular tapered portion 2412 that is the upper cylindrical portion may be a cylindrical portion whose inner surface is parallel to the central axis J1, and in this case also, the surface is formed in the gap between the outer surface of the upper cap 25 and the inner surface of the upper cylindrical portion. A capillary seal portion in which lubricating oil is held by tension can be formed.

  The motor 1 in FIG. 1 is not limited to an outer rotor type motor, but may be an inner rotor type motor. The motor 1 may be used for purposes other than the recording disk drive.

It is a longitudinal cross-sectional view of a motor. It is a longitudinal cross-sectional view of a bearing mechanism. It is a top view of a sleeve. It is a longitudinal cross-sectional view of a sleeve. It is a bottom view of a sleeve. It is a front view of a shaft. It is a front view of a thrust plate. It is a bottom view of a thrust plate. It is a longitudinal cross-sectional view of a housing main body. It is a top view of a lower cap. It is a longitudinal cross-sectional view of a lower cap. It is a bottom view of an upper cap. It is a longitudinal cross-sectional view of an upper cap. It is an enlarged view of the upper part of a bearing mechanism. It is a figure which shows the structure of a taper seal part. It is a figure which shows the upper part of a taper seal part. It is a figure which shows the flow of an assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a longitudinal cross-sectional view which shows the other example of a bearing mechanism. It is a figure which shows the flow of an assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a figure which shows the assembly of a bearing mechanism. It is a longitudinal cross-sectional view which shows the other example of a bearing mechanism. It is a longitudinal cross-sectional view which shows the other example of a bearing mechanism. It is an enlarged view which shows the other example of a bearing mechanism. It is a longitudinal cross-sectional view which shows the other example of a bearing mechanism.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2, 2a-2e Bearing mechanism 11 Rotor part 12 Stator part 21, 30, 31 Sleeve 22 Shaft 23 Thrust plate 24, 24a Sleeve housing 25 Upper cap 26a 1st flow path 26b 2nd flow path 91 Jig 112 Field Magnets 122 Armature 211 Upper surface of sleeve 212 Outer surface of sleeve 213 Lower surface of sleeve 241 Housing body 242, 242a Lower cap 261 Radial gap 262 Thrust gap 268 Thrust gap 271 First taper seal portion 311 Small hole 911 (Jig) surface 2411, 2411a (Housing main body) cylindrical portion 2412, 2412a Annular taper portion 2413 Housing step portion 2414 Inner side surface (annular taper portion) 2417 First step portion 2417a First groove 2418 R 2421a (a housing body) bottom 2515 second groove 2516 R unit second step portion 2515A 2712 tapering gap J1 central axis S11 to S16, S21 to S25 step

Claims (16)

A fluid dynamic bearing mechanism used in an electric motor,
A cylindrical sleeve centered on a predetermined central axis;
A shaft inserted into the sleeve and having an upper end protruding from the sleeve;
A lubricating oil in which a fluid dynamic pressure is induced that fills a radial gap between the inner surface of the sleeve and the outer surface of the shaft and generates a supporting force to support the shaft;
An upper cap having an opening into which the upper end of the shaft is inserted, and covering an upper surface of the sleeve and an upper portion of the outer surface;
An upper cylindrical portion that surrounds an outer surface of the upper cap and forms a capillary seal portion in which the lubricating oil is held by surface tension in a gap between the upper cap and the outer surface;
As the fluid dynamic pressure is generated when the shaft rotates, the lubricating oil flows in from the lower part of the radial gap or from the dynamic pressure gap communicating with the lower part, and the lower part of the radial gap or the dynamic pressure gap and the capillary seal A first flow path communicating with the section;
A fine hole provided in the sleeve or a gap between the sleeve and the upper cap, which communicates the capillary seal portion and the upper part of the radial gap, and the lubricating oil flows from the first flow path. A second inflow channel;
With
A first step portion that is recessed radially outward from the inner surface toward the upper side is formed above the lubricating oil on the inner surface of the upper cylindrical portion,
A second step portion that is recessed radially inward from the outer surface toward the upper side is formed above the lubricating oil on the outer surface of the upper cap in the central axis direction,
An oil-hydrodynamic bearing mechanism, wherein an oil repellent film is formed on the surfaces of the first step portion and the second step portion. The fluid dynamic bearing mechanism according to claim 1,
The fluid dynamic pressure bearing mechanism, wherein the first stepped portion and the second stepped portion substantially coincide with each other in the central axis direction. The fluid dynamic bearing mechanism according to claim 1 or 2,
The fluid dynamic pressure bearing mechanism, wherein the upper end of the upper cylindrical portion and the upper surface of the upper cap substantially coincide with each other in the central axis direction. The fluid dynamic bearing mechanism according to any one of claims 1 to 3,
The first step portion is formed on an upper portion of the inner surface of the upper cylindrical portion, and the second step portion is formed on an upper portion of the outer surface of the upper cap;
The first step portion and the upper end surface of the upper cylindrical portion are connected by a smooth curved surface, and the second step portion and the upper surface of the upper cap are connected by a smooth curved surface. Fluid dynamic pressure bearing mechanism. The fluid dynamic bearing mechanism according to any one of claims 1 to 4,
The first step portion is a lower edge of a groove formed in the circumferential direction on the inner surface of the upper cylindrical portion, and the second step portion is formed in the circumferential direction on the outer surface of the upper cap. A fluid dynamic pressure bearing mechanism characterized by being a lower edge of a groove. The fluid dynamic bearing mechanism according to any one of claims 1 to 5,
A fluid dynamic bearing mechanism, further comprising a bottomed cylindrical sleeve housing having a lower cylindrical portion and a upper cylindrical portion covering a lower portion of the outer surface of the sleeve. The fluid dynamic bearing mechanism according to claim 6,
The sleeve housing has a housing step portion that connects between the upper cylindrical portion and the lower cylindrical portion and whose diameter increases toward the upper side, and the inside of the housing step portion by a surface including the central axis The fluid dynamic pressure bearing mechanism is characterized in that the cross-sectional shape of the edge of the is substantially arc-shaped. The fluid dynamic bearing mechanism according to claim 7,
The fluid dynamic pressure bearing mechanism, wherein the upper cylindrical portion, the housing step portion, and the lower cylindrical portion are formed by pressing a plate-shaped or cylindrical material. An electric motor,
A fluid dynamic pressure bearing mechanism according to any one of claims 1 to 8,
A rotor portion attached to the upper end of the shaft and having a field magnet;
A stator portion having the armature facing the field magnet, wherein the fluid dynamic bearing mechanism is fixed;
A motor comprising: A method of manufacturing a fluid dynamic pressure bearing mechanism used for an electric motor,
a) a step of press-fitting an upper cap having an opening at the center thereof on the upper portion of the cylindrical sleeve, covering the upper surface of the sleeve and the upper portion of the outer surface;
b) attaching an upper cylindrical portion to the sleeve that surrounds the outer surface of the upper cap and forms a gap with the outer surface of the upper cap;
With
An inner surface of the upper cylindrical portion has a first step portion that is recessed radially outward from the inner surface toward the upper side, and the outer surface of the upper cap has a diameter from the outer surface toward the upper side. Having a second step portion recessed inward in the direction,
The step b) determines the relative position of the second stepped portion with respect to the first stepped portion in the central axis direction by bringing the upper end of the upper cylindrical portion and the upper surface of the upper cap into contact with one jig. A method of manufacturing a fluid dynamic bearing mechanism, comprising: a step. It is a manufacturing method of the fluid dynamic bearing mechanism according to claim 10,
The method of manufacturing a fluid dynamic pressure bearing mechanism, further comprising a step of applying an oil repellent agent to the upper side of the first step portion of the upper cylindrical portion and the upper side of the second step portion of the upper cap. It is a manufacturing method of the fluid dynamic bearing mechanism according to claim 10 or 11,
In the step b), the upper end of the upper cylindrical portion and the upper surface of the upper cap are in contact with a plane perpendicular to the central axis of the jig. A method for manufacturing a fluid dynamic bearing mechanism according to any one of claims 10 to 12,
The method of manufacturing a fluid dynamic pressure bearing mechanism, wherein the upper cylindrical portion is a part of a sleeve housing having a lower cylindrical portion that covers a lower portion of the outer surface of the sleeve. It is a manufacturing method of the fluid dynamic bearing mechanism according to claim 13,
The sleeve housing has a housing step portion that connects between the upper cylindrical portion and the lower cylindrical portion and whose diameter increases toward the upper side, and the inside of the housing step portion by a surface including the central axis The cross-sectional shape of the edge is substantially arc-shaped,
In the step b), the sleeve is inserted into the sleeve housing from the upper cylindrical portion toward the lower cylindrical portion. A cylindrical sleeve;
A shaft member having a shaft inserted into the sleeve and having an upper end protruding from the sleeve and a thrust plate located at a lower end of the shaft;
A cylindrical housing body having a lower cylindrical portion covering at least a lower portion of the outer surface of the sleeve;
A bottomed cylindrical lower cap covering the lower surface of the thrust plate;
A fluid dynamic pressure bearing mechanism comprising:
a) inserting the sleeve into the lower cylindrical portion of the housing body;
b) inserting the shaft of the shaft member from below the sleeve to bring the upper surface of the thrust plate into contact with the lower surface of the sleeve;
c) moving the shaft member relative to the sleeve to secure a thrust gap of a predetermined size between the lower surface of the sleeve and the upper surface of the thrust plate;
d) fitting the lower cap to the lower part of the outer side surface of the housing body, and contacting the inner bottom surface of the lower cap and the lower surface of the thrust plate;
e) fixing the lower cap to the housing body;
A method for producing a fluid dynamic bearing mechanism, comprising: A cylindrical sleeve;
A shaft member having a shaft inserted into the sleeve and having an upper end protruding from the sleeve and a thrust plate located at a lower end of the shaft;
A lower cylindrical portion covering at least a lower portion of the outer surface of the sleeve, and a bottomed cylindrical sleeve housing having a bottom portion covering the lower surface of the thrust plate;
A fluid dynamic pressure bearing mechanism comprising:
a) inserting the shaft of the shaft member from below the sleeve to bring the upper surface of the thrust plate into contact with the lower surface of the sleeve;
b) moving the shaft member relative to the sleeve to secure a thrust gap of a predetermined size between the lower surface of the sleeve and the upper surface of the thrust plate;
c) externally fitting the lower cylindrical portion of the sleeve housing to a lower portion of the outer surface of the sleeve, and bringing the inner bottom surface of the sleeve housing into contact with the lower surface of the thrust plate;
d) fixing the sleeve housing to the sleeve;
A method for producing a fluid dynamic bearing mechanism, comprising:

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