JP4948825B2 - Bearing member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a bearing member having an electroformed part and a manufacturing method thereof.

  This type of bearing member uses the fact that the surface deposited on the master surface, which is the molding base of the electroformed part, can be formed with high accuracy following the surface accuracy of the master surface. It is suitably used as a bearing member that constitutes a bearing surface.

For example, Japanese Patent Application Laid-Open No. 2003-56552 (Patent Document 1) proposes a bearing member in which an electroformed part is integrally molded as an insert part. This bearing member is formed by depositing a cylindrical electroformed part, which is an electroformed shell, in a region other than the non-conductive masking part of the master shaft that is the molding base of the electroformed part, and this electroformed part serves as a bearing. After the member is molded with resin, the electroformed part of the bearing member is separated from the master shaft, so that the inner peripheral surface of the electroformed part that becomes the separation surface can be used as it is as a bearing surface It is.
JP 2003-56552 A

  In the bearing member formed by the above method, the separation between the electroformed part and the master shaft is performed along with the release of the residual stress, so that the separation between the outer peripheral surface of the master shaft and the inner peripheral surface of the electroformed part is performed. The gap is uniform in the axial direction. Conventionally, since the electroformed part is formed over the entire length in the axial direction of the bearing member, in the above method, the entire length of the bearing member is provided between the inner peripheral surface of the bearing member and the outer peripheral surface of the bearing member. Only gaps of uniform width can be obtained.

  However, depending on the required characteristics of the bearing, gaps with partially different widths may be required. For example, when a seal space is formed at the end of the bearing member to prevent oil leakage, or when an escape portion is formed between two bearing surfaces, the inner peripheral surface of the bearing member and the outer peripheral surface of the shaft member It is necessary to form a gap having a width larger than that of the bearing gap.

  The gaps with different radial dimensions in the axial direction (different-diameter gaps) can also be obtained by, for example, post-processing the inner peripheral surface of the electroformed part and enlarging the inner diameter dimension. Since the thickness is usually 1 mm or less, it is not practical in consideration of accuracy and cost.

  Accordingly, an object of the present invention is to obtain a highly accurate different-diameter gap at a low cost.

In order to achieve the above object, the present invention comprises an electroformed part formed by electrolytically depositing a target metal on a master surface, and a molded part formed integrally with the electroformed part, and has an inner periphery of the electroformed part. The bearing member is formed with a bearing surface for supporting the shaft member on the surface, and the inner peripheral surface is formed by the inner peripheral surface of the molding part and the inner peripheral surface of the electroformed part separated from the master surface. and the inner circumferential surface of the forming portion, Chi lifting a step with respect to the inner peripheral surface of the electroformed part, to provide a bearing member which is a forming surface which is molded by the film formed on the surface of the master.

  Thus, according to the present invention, since the inner peripheral surface of the bearing member is formed by the inner peripheral surface of the molded part and the inner peripheral surface of the electroformed part, there is a gap between the outer peripheral surface of the shaft member. However, it is formed not only between the inner peripheral surface of the electroformed part but also between the inner peripheral surface of the molded part. At this time, the inner peripheral surface of the molded part has a step with respect to the inner peripheral surface of the electroformed part, so that a different-diameter gap can be formed between the inner peripheral surface of the molded part and the outer peripheral surface of the shaft member. it can. In addition, the inner peripheral surface of the electroformed part formed by electroforming can be obtained with high precision, and the inner peripheral surface of the molded part can also be obtained with high precision by using the inner peripheral surface of the molded part as a molding surface. . Therefore, a different diameter gap formed between the inner peripheral surface and the outer peripheral surface of the shaft member can be obtained with high accuracy.

  The bearing member configured as described above includes, for example, this bearing member and a shaft member inserted into the inner periphery of the bearing member, and a radial gap is formed between the inner peripheral surface of the molded portion and the outer peripheral surface of the shaft member. It can be provided as a bearing device. In this case, the seal space can be formed by the gap in the radial direction. Further, the escape portion can be formed by the radial gap.

  Further, as the shape of the different-diameter gap, a configuration in which one of the inner peripheral surfaces of the electroformed portion and the molded portion is disposed on both axial sides of the other inner peripheral surface is conceivable. For example, when the seal space is formed by the gap in the radial direction, the inner peripheral surface of the molded part is arranged on both sides in the axial direction of the inner peripheral surface of the electroformed part, and the radial gap is arranged in the axial direction of the bearing device. It is preferable to form at both ends. In the case where the clearance portion is formed by the radial gap, the inner peripheral surface of the electroformed portion is arranged on both sides in the axial direction of the inner peripheral surface of the molded portion, and the radial gap is formed into a plurality of bearing surfaces. It is preferable to form in between. Of course, the gap of different diameters according to the present invention is not limited to the configuration illustrated above, and can take various forms.

In order to achieve the above object, the present invention comprises an electroformed part formed by electrolytically depositing a target metal on a master surface, and a molded part formed integrally with the electroformed part. When manufacturing a bearing member having a bearing surface on the inner peripheral surface , electroforming is performed using a master having a non-conductive coating formed on a part of the surface, and then the electroformed portion formed on the master surface and non-conductive What line injection molding sex film while insert after forming the inner peripheral surface of the molded part in a non-conductive coating, provide a method of manufacturing a bearing member, characterized in that the removal of the non-conductive coating To do.

  In order to form the inner peripheral surface of the bearing member having the inner peripheral surface of the electroformed part and the inner peripheral surface of the molded part having a step with respect to the inner peripheral surface of the electroformed part, for example, the master shaft is a stepped shaft. When the shape master is used, the shape of the inner peripheral surface of the molded product basically depends on the shape of the inner peripheral surface of the master shaft, so the degree of freedom of the inner peripheral surface shape is reduced. Moreover, it takes time and effort to process the master axis for each shape change or dimension change, which causes an increase in cost.

  On the other hand, electroforming is performed using a master shaft whose surface is partially covered with a non-conductive coating, and then injection molding is performed by inserting the master shaft including the electroformed portion and the non-conductive coating. Thereafter, if the master shaft is separated and the non-conductive film is removed, the inner peripheral surface of the bearing member independent of the surface shape of the master can be obtained, so that the degree of freedom in shape can be increased.

  In particular, when the bearing member has a structure in which one of the inner peripheral surface of the electroformed portion and the molded portion is disposed on both sides in the axial direction of the other inner peripheral surface, the former method uses the master shaft after injection molding. When separating, the step on the outer peripheral surface of the master shaft and the step on the inner peripheral surface of the bearing member interfere with each other in the axial direction. Since the master can have a uniform diameter, this type of interference can be eliminated, and the master and the bearing member can be reliably separated.

  Further, since a master with a uniform diameter can be used as the master (particularly for the shaft portion), the manufacturing cost can be reduced. Since the non-conductive film only needs to be formed on the surface of the master, its control is relatively easy compared to the case where high-precision processing is performed on the inner peripheral surface, and further cost reduction can be achieved. It is.

  As a method for forming the non-conductive film on the master surface, for example, a general coating method such as a spin coating method can be used. In addition to this, it is possible to use a method in which a small amount of droplet-like ink is supplied to the master surface by an ink jet method or the like, and a film is formed with such an aggregate of inks. As materials suitable for non-conductive coatings, resin materials with excellent plating resistance (resistance to electrolyte solution), environmental resistance, heat resistance, and solvent solubility are selected and used in consideration of the work process. It is preferable to do this.

  However, what forms the inner peripheral surface of the resin portion does not need to be a non-conductive coating for masking the master surface, and may be any material that can be removed after the formation of the resin portion. Therefore, as a method of forming a gap of different diameter, when producing a bearing member having a bearing surface in the electroformed part, after performing electroforming using a master having a non-conductive coating formed on a part of the surface, After removing the non-conductive film, forming a resin layer in part or all of the removal area, and then performing injection molding with the electroformed part of the master surface and the resin layer inserted, and then removing the resin layer A way to do it is also conceivable. In this case, the material for the non-conductive film may be any material that mainly satisfies the plating resistance, and the material for the resin layer may be any material that has excellent heat resistance and is easily soluble in a solvent. Thereby, the selection range of the material which can be used spreads, and a cheaper material can be selected and used.

  As described above, according to the present invention, a highly accurate different diameter gap can be obtained at low cost.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 shows a cross-sectional view of a bearing device 1 according to an embodiment of the present invention. In FIG. 1, a bearing device 1 includes a shaft member 2 and a bearing member 3 capable of inserting the shaft member 2 into the inner periphery. Of these, the bearing member 3 includes an electroformed part 4 and a molded part 5, and is integrally injection-molded with a resin material using the electroformed part 4 as an insert part.

  A region of the inner peripheral surface of the bearing member 3 excluding both axial ends is formed by the inner peripheral surface 4 a of the electroformed part 4. Between the inner peripheral surface 4a of the electroformed part 4 and the outer peripheral surface 2a of the opposing shaft member 2, a bearing clearance 6 having a clearance width C1 is formed. Further, the second molding surfaces 5a and 5a that are located at both ends in the axial direction and constitute the inner circumferential surface of the bearing member 3 together with the inner circumferential surface 4a are described later, but the outer surface of the non-conductive coating 9 (molding surface 9a1). And has a step with respect to the inner peripheral surface 4 a of the electroformed part 4. In this embodiment, the second molding surface 5a is a cylindrical surface having a constant diameter, and a radial gap 7 is formed between the outer peripheral surface 2a of the opposing shaft member 2. The gap width C <b> 2 of the radial gap 7 is larger than the gap width C <b> 1 of the bearing gap 6.

  In this embodiment, the radial gap 7 becomes a seal space for the lubricating oil filled in the bearing. When the bearing gap 6 is filled with the lubricating oil, the oil surface of the lubricating oil always has a seal space at both ends in the axial direction. Maintained within (radial gaps 7, 7). The bearing gap 6 and the radial gap 7 shown in FIG. 1 are both smaller than those of the shaft member 2 and the bearing member 3, but in FIG. The gap width C1 and the gap width C2 of the radial gap 7 are drawn larger (exaggerated) than the radial dimension of the shaft member 2.

  In the bearing device 1 having the above-described configuration, when the shaft member 2 is relatively rotated, the lubricating oil filled in the bearing gap 6 forms an oil film, and the shaft member 2 is relative to the bearing member 3 in the radial direction via the oil film. It is supported rotatably. At this time, since the radial gap 7 serving as a seal space is formed adjacent to the atmosphere opening side of the bearing gap 6, the lubricating oil leaks from the bearing gap 6 to the outside of the bearing with the relative rotation of the shaft member 2. It is possible to keep the lubricating oil inside the bearing.

  Hereinafter, an example of the manufacturing process of the bearing device 1 will be described focusing on the manufacturing process of the bearing member 3.

  The bearing member 3 forms a non-conductive film 9 on the surface of a master 8 used in electroforming, and electroforms the master 8 on which the non-conductive film 9 is formed to form an electroformed part 4. A process, a process of performing molding (insert molding) of the bearing member 3 using the electroformed part 4 and the master 8 having the nonconductive coating 9 as an insert part, a process of separating the electroformed part 4 and the master 8, and a bearing member 3 through a step of removing the non-conductive coating 9 from the substrate 3.

  In this embodiment, the master 8 serving as a molding base of the electroformed part 4 has an axial shape. For example, the master 8 is formed of a stainless steel that has been subjected to a quenching process so as to have a perfectly circular cross-sectional shape and a uniform diameter in the axial direction. The material of the master 8 can be arbitrarily selected from metals and non-metals as long as it has masking properties, electrical conductivity, and chemical resistance, such as a chromium alloy and a nickel alloy, in addition to stainless steel. is there.

  The master 8 may be a solid shaft in which a hollow shaft or a hollow portion is filled with resin in addition to the peeled shaft (solid shaft). Moreover, since the outer peripheral surface accuracy of the master 8 directly affects the surface accuracy of the inner peripheral surface 4a of the electroformed part 4 serving as a bearing surface, it is desirable that the master 8 be finished as high as possible.

  On the surface of the master 8, a non-conductive coating 9 for masking is formed in a region excluding the region where the electroformed part 4 is to be formed. Further, in this embodiment, the non-conductive coating 9 is for forming the second molding surface 5a of the molding unit 5 and forming the radial gap 7 between the outer peripheral surface 2a of the shaft member 2. . Therefore, as shown in FIG. 2, in the nonconductive film 9 formed on the surface of the master 8, the portion (molded portion 9 a) corresponding to the second molded surface 5 a of the molded portion 5 is meat compared to the other portions. It is formed thick.

  Various methods can be used as a method of forming the non-conductive coating 9 on the surface of the master 8, and examples thereof include a spin coating method. In addition, a method of supplying a small amount of droplet-like ink to the master surface by an ink jet method or the like and forming the non-conductive film 9 with an aggregate of such a minute amount of ink can be considered. Among the methods described above, the former is an excellent method for forming a uniform-thickness film in a short time, whereas the latter is an excellent method for forming a fine and complex-shaped film. . For this reason, it is preferable to use the above-mentioned method properly in accordance with the shape of the nonconductive film 9 to be formed.

  As a material for forming the non-conductive coating 9, not only insulation (non-electrolytic precipitation), but also corrosion resistance to the electrolyte solution, and further, durability (heat resistance) with respect to the molding temperature of the molded part 5 to be described later and solubility to the solvent It is preferable that the material has ease (solubility), and examples thereof include vinyl acetate resin, ethyl cellulose, acetylbutyl cellulose, shellac (natural resin), and the like.

  Electroforming is performed by immersing the master 8 in an electrolyte solution containing metal ions such as Ni and Cu, and energizing the electrolyte solution to remove the target metal from the surface of the master 8 excluding the nonconductive film 9 ( This is performed by electrolytic deposition on the exposed area of the outer peripheral surface 8a. The electrolyte solution may contain a sliding material such as carbon or a stress relaxation material such as saccharin as necessary. The kind of the deposited metal is appropriately selected according to required properties such as hardness required for the bearing surface of the bearing or resistance to lubricating oil (oil resistance).

  By passing through the above process, as shown in FIG. 3, the electroformed shaft 10 in which the electroformed part 4 is formed in a region other than the non-conductive coating 9 forming region on the surface of the master 8 is manufactured. At this stage, the electroformed shaft 10 forms a cylindrical electroformed portion 4 in a partial region in the axial direction of the outer peripheral surface 8 a of the master 8, and is adjacent to both ends of the electroformed portion 4 in the axial direction. Nine molded parts 9a are formed. In addition, the thickness of the electroformed part 4 is calculated | required since it will lead to the durable fall of a bearing surface (inner peripheral surface 4a), etc., when this is too thin, and the peelability from the master 8 may fall when too thick. The optimum thickness is set in accordance with the bearing performance, the bearing size, and the application, for example, in the range of 10 μm to 200 μm.

  The electroformed shaft 10 manufactured through the above steps is supplied and arranged as an insert part in a mold for insert-molding the bearing member 3.

  FIG. 4 conceptually shows an insert molding process of the bearing member 3, and a runner 13, a gate 14, and a cavity 15 are provided in a mold including the movable mold 11 and the fixed mold 12. In this embodiment, the gate 14 is a dotted gate shown in the figure, and a plurality of gates 14 are provided at equal intervals in the circumferential direction at positions corresponding to one end surface in the axial direction of the molding portion 5 of the molding die. The gate area of each gate 14 is set to an appropriate value according to the viscosity of the molten resin to be filled and the shape of the molded product.

  In the mold configured as described above, the movable mold 11 is brought close to the fixed mold 12 and clamped while the electroformed shaft 10 is positioned and arranged. At this time, both the electroformed part 4 and the nonconductive film 9 formed on the surface of the electroformed shaft 10 (master 8) are in the cavity 15. Next, in a state where the mold is clamped, molten resin P is injected and filled into the cavity 15 through the sprue (not shown), the runner 13, and the gate 14, and the molded part 5 is integrated with the electroformed shaft 10. Mold.

  Thereby, the shaping | molding part 5 is shape | molded by the shape according to the cavity 15 provided in the metal mold | dies 11 and 12. FIG. Moreover, the area | region located in the outer-diameter side of the electroformed part 4 among the internal peripheral surfaces of the shaping | molding part 5 is shape | molded by the outer peripheral surface 4b of the electroformed part 4 (1st shaping | molding surface 5b). Moreover, the area | region located in the axial direction both ends side of the electroformed part 4 among the internal peripheral surfaces of the shaping | molding part 5 is shape | molded according to the shaping | molding surface 9a1 of the nonelectroconductive film 9 which forms a part of cavity 15. FIG. (Second molding surfaces 5a, 5a).

  Examples of the molten resin P include crystalline polymers such as liquid crystal polymer (LCP), polyphenylene sulfide (PPS) resin, polyacetal resin, polyamide resin, polyphenylsulfone (PPSU), polyethersulfone (PES), and polyether. Amorphous resin such as imide (PEI) can be used. Of course, these are merely examples, and a resin material suitable for the application and use environment of the bearing can be arbitrarily selected. You may add various fillers, such as a reinforcement (regardless of forms, such as a fiber form and a powder form), a lubrication agent, and a electrically conductive agent as needed.

  After the mold opening, the molded product in which the master 8, the nonconductive film 9, the electroformed part 4, and the molded part 5 are integrated is removed from the molds 11 and 12. This molded product is separated into a secondary molded product composed of the electroformed part 4, the nonconductive film 9, and the molded part 5 and the master 8 in a subsequent separation step.

  In the separation step, for example, the inner peripheral surface 4 a of the electroformed part 4 is peeled from the outer peripheral surface 8 a of the master 8 by applying an impact to the master 8 or the electroformed part 4. Thereby, the master 8 is pulled out from the bearing member 3 (electroformed part 4).

  In addition to the above-described means, the electroformed part 4 may be separated by, for example, a method in which the electroformed part 4 and the master 8 are heated (or cooled) to cause a difference in thermal expansion between them, or both. Means using both means (impact and heating) can be used.

  After separating the electroformed part 4 from the master 8, the non-conductive coating 9 remaining on the inner circumferences at both axial ends of the electroformed part 4 is dissolved with a solvent. Thereby, the nonconductive film 9 is removed, and the bearing member 3 as a finished product is obtained. Further, with the removal of the non-conductive coating 9, the second molding surface 5a of the molding part 5 is exposed to the inner periphery of the bearing member 3.

  The bearing device 1 shown in FIG. 1 is completed by inserting the shaft member 2 created separately from the pulled-out master 8 into the inner periphery of the bearing member 3 formed as described above. In this case, the radial clearance width C2 of the radial gap 7 formed between the second molding surface 5a and the outer peripheral surface 2a of the shaft member 2 is equal to the outer peripheral surface of the inner peripheral surface 4a of the electroformed part 4 and the shaft member 2. It is larger than the radial clearance width C1 of the bearing clearance 6 between the surface 2a by the radial thickness of the molded portion 9a of the non-conductive coating 9.

  In this way, the electroformed part 4 is formed in a state where the nonconductive film 9 is formed on the surface of the master 8, and the molding surface of the nonconductive film 9 is formed in the subsequent insert molding of the molded part 5 (bearing member 3). By molding the second molding surface 5a of the molding part 5 with 9a1 and removing the non-conductive coating 9, the inner circumferential surface 5a of the molding part 5 adjacent to the inner circumferential surface 4a of the electroformed part 4 through a step. Can be formed. Also, the bearing gap 6 between the outer peripheral surface 2a of the shaft member 2 and the inner peripheral surface 4a of the electroformed portion 4 is adjacent to the axial gap and the radial gap width is different (C1 <C2). A directional gap 7 can be formed. Accordingly, by appropriately adjusting the shape of the molded portion 9a of the non-conductive coating 9, the inner peripheral surface of the bearing member 3 including the inner peripheral surface 4a of the electroformed portion 4 and a uniform diameter inserted into the inner periphery. The radial gap formed between the outer peripheral surface 2a of the shaft member 2 is not limited by the surface shape of the master 8, and can be formed in a free shape.

  Further, the shape of the outer peripheral surface 8a (surface shape) of the master 8 does not have to be a shape corresponding to the radial gap 7, and may be a cylindrical surface shape having a constant diameter as in the above embodiment. Therefore, it is not necessary to forcibly remove the master 8, and damage to the inner peripheral surface 4a of the electroformed portion 4 serving as a bearing surface can be prevented.

  Further, in the bearing device 1 according to this embodiment, since the inner peripheral surface 4a of the electroformed part 4 is formed with high accuracy, the bearing clearance 6 formed between the outer peripheral surface 2a of the shaft member 2 is increased. High bearing performance (runout accuracy, etc.) can be obtained even if it is set small (about several μm). Therefore, for example, if the radial gap 7 is sized so that the gap width C2 of the radial gap 7 with respect to the gap width C1 of the bearing gap 6 is 3 ≦ (C2 / C1) ≦ 50, it has high sealing performance and dust resistance. This is preferable because it is possible to exhibit (preventing entry of foreign matter from the outside).

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment.

  In the above embodiment, the electroformed part 4 is formed on the master 8 having the nonconductive film 9 formed on the surface, and the electroformed shaft 10 having the nonconductive film 9 and the electroformed part 4 is used as an insert part to form a molded part. While the case where the second molding surface 5a is molded with the molding surface 9a1 of the non-conductive coating 9 has been described while 5 (the bearing member 3) is injection molded, other methods may be employed. For example, as shown in FIG. 5, after the electroformed portion 4 is deposited on the outer peripheral surface 8a of the master 8 having the nonconductive film 9 formed on the surface, the nonconductive film 9 is removed, and the nonconductive film is removed. A resin layer 19 made of a material different from the non-conductive coating 9 is formed in a partly removed region of 9. Then, after molding the molded part 5 (the bearing member 3) using the electroformed shaft 20 on which the resin layer 19 is formed as an insert part (with the electroformed part 4 and the resin layer 19 inserted into the cavity 15), the resin layer A method of removing 19 can be implemented. In this case, the second molding surface 5 a of the molding part 5 is molded following the surface 19 a of the resin layer 19.

  According to such a method, the material for the non-conductive coating 9 does not need to take into consideration the heat resistance at the time of injection molding and the fluidity at the time of removing the coating (ease of flowing into the inner periphery), while the resin layer It is not necessary to consider the corrosion resistance at the time of electroforming and the like for the material for 19. Therefore, the selection range of materials that can be used for each of the coating films 9 and 19 is widened, and it is possible to use cheaper materials. For example, a resin such as vinyl acetate resin, acetylbutyl cellulose, or acetyl cellulose that can be dissolved in a general-purpose solvent such as acetone can be used for the resin layer 19.

  In the above embodiment, the case where the shape of the non-conductive film 9, particularly the shape of the molded portion 9 a is made constant, is exemplified, but of course other shapes may be used. FIG. 6 shows an example thereof, and shows an enlarged main part of the master 8 in which the electroformed part 4 is formed on the outer periphery. In the figure, the non-conductive film 29 formed on the surface of the master 8 has a diameter difference, and is adjacent to the electroformed part 4 in the axial direction on the large diameter part side. By forming the molding part 5 (bearing member 3) using the electroformed shaft provided with the non-conductive coating 29 having such a shape as an insert part, the inner periphery of the molding part 5 is non-conductive as shown in FIG. A large-diameter side inner peripheral surface 5c having a shape following the large-diameter side molding surface 29a of the coating 29 and a small-diameter side inner peripheral surface 5d having a shape following the small-diameter side molding surface 29b are respectively formed. Among these, the large-diameter side inner peripheral surface 5c has a step between the axially adjacent inner peripheral surface 4a of the electroformed part 4. Thus, in a state where the shaft member 2 is inserted into the inner periphery of the bearing member 3, there is a gap between the large-diameter side inner peripheral surface 5c and the small-diameter side inner peripheral surface 5d and the outer peripheral surface 2a of the opposing shaft member 2. A radial gap 27 having a different width in the axial direction (C3> C4) is formed.

  In this case, a relatively large amount of lubricating oil is retained in the region of the clearance gap C3 in the radial gap 27, and the region of the clearance width C4 in the radial clearance 27 functions as a seal space. Therefore, abundant lubricating oil can always be supplied to the bearing surface constituted by the inner peripheral surface 4a of the electroformed portion 4 or the bearing gap 6 without continuously supplying the lubricating oil into the bearing. Such a bearing device can be used stably over a long period of time.

  FIG. 8 shows another embodiment of the nonconductive film 9 that can be formed on the surface of the master 8. The non-conductive film 39 in the figure has a so-called tapered surface shape in which the film thickness is gradually increased in the axial direction, and is adjacent to the electroformed part 4 on the thin wall side (small diameter side). By forming the molded part 5 (bearing member 3) using the electroformed shaft provided with the non-conductive coating 39 having such a shape as an insert part, as shown in FIG. A tapered inner peripheral surface 5e having a shape following the tapered forming surface 39a of the coating 39 is formed. The lower end side (small diameter side) of the tapered inner peripheral surface 5e has a step between the inner peripheral surface 4a of the electroformed part 4 adjacent in the axial direction. Thus, in a state where the shaft member 2 is inserted into the inner periphery of the bearing member 3, the gap width C5 is directed upward in the axial direction between the tapered inner peripheral surface 5e and the outer peripheral surface 2a of the opposing shaft member 2. Thus, a radial gap 37 that is gradually enlarged is formed.

  In this case, in the radial gap 37, a sealing action by capillary force occurs. Therefore, a higher sealing function can be exhibited in the radial gap 37 as compared to a sealing space having a constant diameter as shown in FIG.

  In the above embodiment, the non-conductive coatings 9, 29, and 39 are formed on the surface of the master 8 so that the radial gaps 7, 27, and 37 are formed at both axial ends of the bearing member 3. It is also possible to form in other places. For example, a non-conductive coating 9 having a predetermined thickness is formed in advance at a location corresponding to the center in the axial direction of the bearing member 3, and electroforming is performed in this state. Thereby, for example, as shown in FIG. 10, an inner peripheral surface 5 a having a larger diameter than the inner peripheral surface 4 a of the electroformed part 4 can be formed as a molding surface of the molded part 5 between the plurality of electroformed parts 4. it can. Therefore, a radial gap 7 (gap width C2 C2> C1) as a so-called relief portion is formed between a plurality of (two in the illustrated example) bearing gaps 6 (gap width C1) spaced apart in the axial direction. The formed bearing member 3 can be obtained.

  In any case, the position, shape, size, etc. of the radial gaps 7, 27, 37 can be adjusted by the non-conductive coatings 9, 29, 39. For example, in the above-described embodiment, the case where the radial gaps 7, 27, and 37 are formed at both ends in the axial direction of the bearing member 3 is illustrated, but may be formed only at one end in the axial direction. Of course, the above-described configuration is the same when the inner peripheral surface (second molding surface 5a) of the molded part 5 is molded with the resin layer 19 shown in FIG. 5 instead of the non-conductive coatings 9, 29, and 39. It is applicable to.

  In the above embodiment, the case where the nonconductive films 9, 29, 39 are removed after the master 8 is pulled out has been described. However, the above steps can be performed in the reverse order. That is, as long as the non-conductive coatings 9, 29, 39 can be dissolved by the solvent from the axial ends, the non-conductive coatings 9, 29, 39 can be removed prior to the master 8 being pulled out. Of course, as long as the non-conductive coatings 9, 29, 39 are peeled and removed from the molded part 5 integrally with the master 8 when the master 8 is pulled out, it does not matter. Of course, it is also possible to use the shaft 8 as it is without pulling out the master 8.

  Moreover, although the case where the molding part 5 formed integrally with the electroformed part 4 was formed by injection molding of resin was illustrated in the above embodiment, other materials, for example, metal mold molding (mold molding), etc. It is also possible to form the molded part 5. In addition to this, for example, the molded part 5 can be formed of a sintered metal formed by compacting (molding) metal powder and then sintering.

  In the above embodiment, a case where a fluid perfect circle bearing is configured as a bearing formed in the bearing gap 6 has been described. However, in addition to this, a dynamic pressure generating portion for generating a fluid dynamic pressure action is included. The structure provided in the surrounding surface 4a is employable. In this case, for example, although not shown, a region in which a plurality of grooves (dynamic pressure grooves) inclined with respect to the axial direction are arranged in a herringbone shape can be formed. Alternatively, although not shown, for example, a plurality of arc surfaces are formed on the inner circumferential surface 4a, and a radial clearance between the arc surface and the perfect circular outer circumferential surface 2a of the shaft member 2 facing the arc surface is formed. A so-called multi-arc bearing reduced in a wedge shape toward the circumferential direction can also be configured. These radial dynamic pressure generating portions can be provided on the inner peripheral surface (inner peripheral surface 4 a) side of the bearing member 3 or on the outer peripheral surface 2 a side of the shaft member 2.

  Further, as described above, the non-conductive coatings 9, 29, 39 are intermittently formed in the circumferential direction or the axial direction in addition to being continuously formed in the circumferential direction on the outer peripheral surface 8a of the master 8. May be. As a bearing surface shape when formed discontinuously in the circumferential direction, for example, although not shown, the inner peripheral surface 4a of the electroformed part 4 and the molded part 5 formed by the non-conductive coatings 9, 29, 39 are provided. There is a so-called step bearing in which inner circumferential surfaces are alternately arranged in the circumferential direction, and thereby a plurality of axial grooves are formed on the inner circumferential surface of the bearing member 3.

  Moreover, although what was called a radial bearing part was described in the above embodiment, this invention is applicable also to the bearing apparatus (bearing member) which provided the thrust bearing part (thrust bearing surface). For example, although not shown in the drawings, the present invention is also applied to a bearing member in which both the inner peripheral surface of the electroformed part serving as a radial bearing surface and the end surface (axial orthogonal end surface) of the electroformed part serving as a thrust bearing surface are formed. Can be applied.

  In the above embodiment, the lubricating oil is exemplified as the fluid that fills the inside of the bearing device 1 and forms the lubricating film between the bearing gaps. However, the present invention is not limited to this. For example, a gas such as air or a magnetic fluid is used. It is also possible to use a lubricant having fluidity such as lubricant grease or the like.

  The bearing device described above can be used by being incorporated in a motor for information equipment, for example. Hereinafter, a configuration example in which the bearing device is applied to the motor bearing will be described with reference to FIG. In addition, about the site | part and member which make the structure and effect | action same as embodiment shown in FIGS. 1-10 the same reference number, the duplicate description is abbreviate | omitted.

  FIG. 11 shows a cross-sectional view of the motor 100 in which the bearing device 101 is incorporated. The motor 100 is used as a spindle motor for a disk drive device such as an HDD, for example, and includes a bearing device 101 that rotatably supports a shaft member 102 in a non-contact manner, and a rotor ( Disk hub) 111, and a stator coil 112 and a rotor magnet 113 that are opposed to each other with a gap in the radial direction, for example. The stator coil 112 is attached to the outer periphery of the bracket 114, and the rotor magnet 113 is attached to the inner periphery of the disk hub 111. The disk hub 111 holds one or more disks D such as magnetic disks. When the stator coil 112 is energized, the rotor magnet 113 is rotated by electromagnetic force between the stator coil 112 and the rotor magnet 113, whereby the disk hub 111 and the disk D held by the disk hub 111 are integrated with the shaft member 102. Rotate to.

  In this embodiment, the bearing device 101 includes a bearing member 103 and a shaft member 102 that is inserted into the inner periphery of the bearing member 103. The bearing member 103 includes a bottomed cylindrical electroformed portion 104 having an open end, and a molded portion 105 formed integrally with the electroformed portion 104. The inner peripheral surface 105a of the molding portion 105 having a larger diameter than the inner peripheral surface 104a of the electroformed portion 104 and having a step between the inner peripheral surface 104a and the outer peripheral surface 102a of the opposed shaft member 102 is sealed. A radial gap 107 serving as a space is formed. In this case, the inner peripheral surface 105a is molded following the molding surface 9a1 of the non-conductive coating 9 formed on the surface of the master 8, as in the above embodiment.

  In the bearing device 101 configured as described above, when the shaft member 102 rotates, an oil film of lubricating oil is formed in the radial bearing gap 106 between the outer peripheral surface 102a of the shaft member 102 and the bearing surface (inner peripheral surface 104a) of the bearing member 103. Thus, a radial bearing portion R that supports the shaft member 102 rotatably in the radial direction is formed. At the same time, a thrust bearing portion T that supports the shaft member 102 rotatably in the thrust direction is formed between the lower end surface 102b of the shaft member 102 and the inner bottom surface 104b of the electroformed portion 104 opposed thereto.

  FIG. 11 illustrates the case where the thrust bearing portion T is constituted by a so-called pivot bearing. However, in the present invention, the shaft member 102 is supported in a non-contact manner in the thrust direction by dynamic pressure generating means such as a dynamic pressure groove. It can be applied to a hydrodynamic bearing.

  The bearing device of the present invention is not limited to the above examples, and can be widely applied to support a rotating shaft of a motor. As described above, according to the present invention, the bearing device can be provided with excellent bearing performance including a sealing function due to a high degree of freedom in shape on the inner peripheral surface of the bearing member. It is also suitable for rotating shaft support in small motors for information equipment that require high rotational accuracy, such as spindle motors for driving magneto-optical disks for optical disks, polygon scanner motors for laser beam printers, etc. Can be used for

It is sectional drawing of the bearing apparatus which concerns on one Embodiment of this invention. It is a perspective view of the master which formed the nonelectroconductive film. It is a perspective view of an electroformed shaft. It is a figure which shows notionally the molding process of a bearing member. It is a perspective view of the electroformed shaft in which the resin film was formed. It is a principal part enlarged view which shows the other form of an electroformed shaft. It is a principal part enlarged view of the bearing apparatus which concerns on another form. It is a principal part enlarged view which shows the other form of an electroformed shaft. It is a principal part enlarged view of the bearing apparatus which concerns on another form. It is sectional drawing of the bearing apparatus which concerns on another form. It is sectional drawing which shows one form of the motor provided with the bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing apparatus 2 Shaft member 3 Bearing member 4 Electroformed part 5 Molding part 6 Bearing clearance 7 Radial clearance 8 Master 9 Non-conductive coating 15 Cavity 19 Resin layers 27 and 37 Radial clearance 29 and 39 Non-conductive coating 100 Motor DESCRIPTION OF SYMBOLS 101 Bearing apparatus 102 Shaft member 103 Bearing member 107 Radial direction clearance C1, C2, C3, C4, C5 Radial clearance width R Radial bearing part T Thrust bearing part

Claims (7)

An electroformed part formed by electrolytically depositing a target metal on the master surface, and a molded part formed integrally with the electroformed part, and a bearing surface for supporting the shaft member is provided on the inner peripheral surface of the electroformed part. A formed bearing member,
The inner peripheral surface is formed by the inner peripheral surface of the molded part and the inner peripheral surface of the electroformed part peeled from the master surface , and the inner peripheral surface of the molded part is Chi lifting the step bearing member which is a forming surface which is molded by the film formed on the surface of the master. The bearing member according to claim 1 , wherein the inner peripheral surface of the molded part is a molded surface exposed to the inner periphery of the bearing member by dissolving the coating after the molding of the molded part .   A bearing comprising the bearing member according to claim 1 and a shaft member inserted in the inner periphery of the bearing member, wherein a radial gap is formed between the inner peripheral surface of the molded part and the outer peripheral surface of the shaft member. apparatus.   The bearing device according to claim 3, wherein a seal space is formed by the gap in the radial direction.   The bearing device according to claim 3, wherein a relief portion is formed by the gap in the radial direction. Producing a bearing member having an electroformed portion formed by electrolytically depositing a target metal on the master surface and a molded portion formed integrally with the electroformed portion, and having a bearing surface on the inner peripheral surface of the electroformed portion. On the occasion
Perform electroforming using the master forming a non-conductive coating on a portion of the surface, then the line I injection molding while inserting the electroformed portion and nonconductive film formed on the surface of the master, the non A method for manufacturing a bearing member , comprising: forming an inner peripheral surface of a molded portion with a conductive film, and then removing the nonconductive film. When manufacturing a bearing member having a bearing surface in the electroformed part,
After electroforming using a master having a non-conductive coating formed on a part of the surface, the non-conductive coating is removed and a resin layer is formed on a part or the whole of the removal region, and then the master surface A method for producing a bearing member, comprising performing injection molding in a state where the electroformed part and the resin layer are inserted, and then removing the resin layer.

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