JP4890202B2 - Bearing member and bearing device including the same - Google Patents

Description

  The present invention relates to a bearing member, in particular, a bearing member having a bearing surface formed of an electroformed part, and a bearing device including the bearing member.

  Bearing devices are widely used as dynamic mechanism parts in various fields such as automobiles, industrial equipment, precision equipment, electricity, and electronics. Especially in sliding bearings and fluid bearings that support rotating bodies, the bearing performance is greatly affected by the surface accuracy of the inner peripheral surface of the bearing member that becomes the bearing surface or the outer peripheral surface of the shaft that faces this inner peripheral surface. Various proposals have been made to obtain bearing surface accuracy.

For example, Japanese Patent Application Laid-Open No. 2003-56552 (Patent Document 1) proposes a bearing member in which a resin part is integrally molded using an electroformed part as an insert part. This bearing member is formed after forming a cylindrical electroformed part, which is an electroformed shell, in the non-masking region of the master shaft, which is the molding base of the electroformed part, and molding the resin part using this electroformed part as an insert part By separating the electroformed part from the master shaft, the inner peripheral surface of the electroformed part that becomes the separation surface (deposition start surface) can be used as it is as the inner peripheral surface (bearing surface) of the bearing member. To do.

Here, electroforming is a technique for forming a metal layer by electrodeposition (electrolytic deposition) of metal ions on the master surface. Due to the characteristics of electroforming, the surface shape of the master is high on the inner surface of the electroformed part. Transferred with accuracy. Therefore, if a master shaft with improved surface accuracy is used, an inner peripheral surface (bearing surface) having high surface accuracy can be obtained at low cost without any post-processing.
JP 2003-56552 A

On the other hand, in this type of bearing member, because of problems such as workability, the electroformed part is used as an insert part, and the resin part (molded part) that holds the electroformed part on the inner periphery is integrated with the electroformed part. In many cases, the mold is formed and the electroformed part is fixed simultaneously with the mold forming. However, if the coupling force between the two members is insufficient, for example, there is a possibility that peeling occurs between the outer peripheral surface of the electroformed part and the inner peripheral surface of the resin part.

  In particular, when the molded product is released from the mold after insert molding, a considerable pulling force acts on the resin part, so the coupling force (prevention force) is improved between the resin part and the electroformed part. It is necessary to plan. Normally, when a molded product is released from a mold, the molded product is ejected from the mold by an extrusion mechanism called an ejector. At that time, the bonding force between the electroformed part and the resin part is discharged. This is because the resin portion that has been subjected to the pushing force by the ejector may come off from the electroformed portion (usually an integral part of the electroformed portion and the master).

  This type of problem can also occur when the master is pulled out of the electroformed part. That is, insert molding of the resin part (molding part) is usually performed by using an integral part of the electroformed part and the master as an insert part, and after molding, an integral part (bearing member) of the electroformed part and the resin part and the master. And are separated. At this time, the drawing of the master is performed in a state in which an integral product of the electroformed part and the resin part, actually a resin part having a large holding area is held. Therefore, even when the master is pulled out, a considerable pulling force acts on the resin portion. Accordingly, it is necessary to ensure a sufficient bonding force (prevention force) between the resin portion and the electroformed portion.

  In view of the above circumstances, the present invention provides a bearing member that improves the retaining force when releasing a molded product integrally having an electroformed part from a molding die or pulling out a master. Technical issue.

In order to solve the above-mentioned problems, the present invention comprises an electroformed part provided with a separation surface from the master on the inner periphery, and a mold part that is located outside the electroformed part and is formed integrally with the electroformed part. The outer diameter of the electroformed part was reduced in the direction of pulling out the master from the electroformed part by changing the thickness of the electroformed part in the axial direction to make the outer peripheral surface tapered . A bearing member is provided (claim 1). Here, the electroformed part in the present invention includes not only those formed by a method according to electrolytic plating, but also those formed by a method according to electroless plating.

  As described above, the present invention has an outer peripheral surface shape of an electroformed part having a separation surface with a master on the inner periphery and a mold forming part on the outer side, an extrusion direction at the time of mold release, and a pulling direction of the master. Is determined in consideration of According to this configuration, the molded part is formed integrally with the outer peripheral surface of the electroformed part located on the inner side thereof so as to face the part whose outer diameter is enlarged. The electroformed part is engaged in a direction to receive the pushing force by the ejector. Alternatively, when the master is pulled out, the molded part is engaged with the electroformed part in a direction in which the molded part is restrained (receives a restraining force) by a jig or the like. As a result, it is possible to improve the retaining force between the electroformed part and the mold forming part, and it is possible to prevent slipping at the time of mold release or master drawing. In particular, when the inner peripheral surface that becomes the bearing surface is precisely formed following the outer peripheral surface of the master, like the electroformed part, the outer peripheral surface is also precisely formed according to the inner peripheral surface. On the other hand, there may be a case where the retaining force is insufficient with the resin part. However, with the configuration according to the present invention, it is possible to ensure the retaining force by the engagement between the mold part and the electroformed part. It becomes.

  Thus, the electroformed part in which the outer diameter dimension is varied in the axial direction can be formed, for example, by performing electroforming in a state where the facing distance from the electrode is controlled (claim 4). This is because the deposition rate is increased at a location where the facing distance between the anode surface to be an electrode and the master surface is relatively narrow, and the deposition rate is slow at a location where the facing distance is relatively wide. It is formed. In this case, a portion having a low precipitation rate is a small-diameter portion, and a portion having a high precipitation rate compared to the small-diameter portion is a large-diameter portion. Therefore, according to this method, the outer diameter dimension can be easily changed by simply setting the shape or arrangement of the electrode (anode) with respect to the master in accordance with the shape of the electroformed part to be formed. Different electroformed parts can be formed. Of course, since the inner peripheral surface is precisely transferred to follow the master, a very precise inner peripheral surface can be obtained regardless of whether the outer peripheral surface has a different diameter, and this can be used as a bearing surface. Can be used as

As a bearing member having the above-described configuration, for example, one end of the electroformed part is opened and the other end is closed, and the outer diameter of the electroformed part is larger on the other end closed side than on the one end opened side. (Claim 3 ). In this case, regardless of whether or not the master is integrally formed, the side of the molding die that is inserted into the inner periphery of the electroformed portion or the side that holds the master (for example, movable) In many cases, an integrally molded product remains on the mold side. This is because the molded product according to the present invention usually shrinks and molds toward the center of the shaft, and tends to bite into the shaft portion of the master or the inserted mold located on the inner periphery of the electroformed portion. Therefore, if the above-described configuration is adopted, the pushing force by the ejector acts to push the mold forming part from the one end opening side to the other end closing side of the electroformed part. Therefore, if the diameter is larger on the other end closing side than the one end opening side of the electroformed part, the molded part and the electroformed part are engaged in the ejecting direction of the ejector, thereby improving the retaining force. Can be achieved. Of course, in the case of the bearing member having the above-described form, the pulling direction of the master inevitably coincides with the direction from the other end closing side to the one end opening side. It becomes possible.

As described above, the outer diameter of the electroformed part may be set so as to be reduced in the drawing direction of the master (or expanded in the direction of being pushed out by the ejector). case, the outer peripheral surface of, for example, electroformed part, Ru configuration is valid der to shape reduced in diameter in the direction to pull out the master tapered. For example, when the outer peripheral surface of the electroformed part has a stepped shape, the required strength cannot be secured depending on the material of the mold forming part because the extrusion force concentrates on the stepped part at the time of mold release (when ejected with an ejector). There is a fear. On the other hand, in the case of an electroformed part having an outer peripheral surface formed in a taper shape, the force received from the electroformed part by the mold forming part is evenly distributed over the entire surface of the taper surface, and the engagement area is also increased. , The concentration of the engaging force can be relaxed. According to this, it is possible to further strengthen the retaining force.

  Further, in the above configuration, the case where the outer diameter dimension of the electroformed part is varied in the axial direction has been described. In addition, for example, the outer diameter dimension of the electroformed part is varied around the circumferential direction. It is also possible to do. According to this configuration, not only can the electroformed part be prevented from being removed from the molded part, but, for example, when this bearing member is used for supporting the rotation of the shaft, the periphery of the electroformed part with respect to the molded part is prevented. Can function as. In addition, the outer peripheral surface shape for aiming at a rotation stop is not ask | required. For example, a different diameter shape in which the outer diameter dimension is smoothly changed, such as an elliptical shape, or a shape in which the outer diameter dimension changes abruptly, such as a polygonal shape, may be used.

  The bearing member having the above-described configuration is not particularly limited as long as it supports the shaft inserted in the inner periphery. However, as in the present invention, the bearing surface is a separation surface from the master serving as a deposition start surface. Can be suitably used, for example, as a sliding bearing or a fluid bearing that rotatably supports the shaft. Specifically, a radial gap is provided between the inner peripheral surface of the electroformed part and the outer peripheral surface of the shaft, and a bearing member and a shaft inserted in the inner periphery of the bearing member. Can be suitably provided as a bearing device (fluid bearing device) in which the above is formed. Of course, at least one of the inner peripheral surface of the electroformed part that becomes the bearing surface and the outer peripheral surface of the shaft facing this is provided with a dynamic pressure generating part for generating a dynamic pressure action of fluid in the radial gap, It can also be provided as a hydrodynamic bearing device.

  As described above, according to the present invention, it is possible to provide a bearing member that is improved in retaining force when a molded product integrally having an electroformed part is released from a molding die or when a master is pulled out. Can do.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Note that the “up and down” direction in the following description simply indicates the up and down direction in each drawing for convenience of description, and does not specify the installation direction or usage mode of the bearing device or the motor.

  FIG. 1 is a cross-sectional view of a motor incorporating a bearing device 1 according to an embodiment of the present invention. This motor is used, for example, as a cooling motor equipped with a fan. The bearing device 1 rotatably supports the shaft 2, the rotor plate portion 3 provided at one end of the shaft 2, and the radial direction, for example. And a drive unit 4 including a stator coil 4a and a rotor magnet 4b opposed to each other with a gap therebetween. In this embodiment, the base portion of the motor is formed integrally with the mold forming portion 9 of the bearing device 1. A rotor magnet 4b is fixed to the inner periphery of the rotor plate portion 3 via a yoke 5, and one or a plurality of fans (blades) 6 are integrally or separately provided on the outer periphery thereof.

  In the motor having the above configuration, when the stator coil 4a is energized, the rotor magnet 4b is rotated by the exciting force between the stator coil 4a and the rotor magnet 4b. Accordingly, the rotor plate portion 3 and the fan 6 fixed to the rotor plate portion 3 rotate integrally with the shaft 2. By this rotation, the fan 6 generates an air flow in the direction of the rotation axis of the motor, and the air flow is sent toward a component to be cooled (not shown) to cool the component. .

  FIG. 2 shows a cross-sectional view of the bearing device 1. In FIG. 1, the bearing device 1 includes a shaft 2 and a bearing member 7 capable of inserting the shaft 2 into the inner periphery. Among these, the bearing member 7 includes an electroformed part 8 and a mold forming part 9 that is located on the outer periphery of the electroformed part 8 and is formed integrally with the electroformed part 8. In this embodiment, the electroformed part 8 has a bottomed cylindrical shape, opens at the upper end in the axial direction, and closes the lower end in the axial direction. Here, the mold forming portion 9 is formed so as to cover the outer peripheral surface 8a and the lower end surface 8b of the electroformed portion 8 having a bottomed cylindrical shape.

  The inner peripheral surface 8c of the electroformed part 8 functions as a radial bearing surface for the shaft 2 inserted into the inner periphery of the bearing member 7 (electroformed part 8). In this embodiment, the inner peripheral surface 8 c forms a cylindrical surface having a constant diameter, and forms a radial bearing gap 10 between the inner peripheral surface 8 c and the outer peripheral surface 2 a of the opposite shaft 2. The internal space including the bearing gap 10 is filled with a lubricating fluid such as lubricating oil, and an oil film of lubricating oil is formed in the bearing gap 10 when the shaft 2 rotates. The shaft 2 is supported so as to be relatively rotatable through the oil film.

  In this embodiment, the upper end surface 8d at the bottom of the electroformed portion 8 is in contact with the one end surface 2b of the shaft 2 in a state where the shaft 2 is inserted into the inner periphery of the bearing member 7, and the shaft 2 is rotated. In the state, the shaft 2 is contact-supported (pivot supported) so as to be relatively rotatable.

  The outer peripheral surface 8a of the electroformed part 8 has a shape in which the outer diameter is made different in the axial direction. In the molding process of the mold forming part 9 to be described later, the side that receives the pushing force by the ejector has a small diameter, and the pushing force is reduced. The side opposite to the receiving side has a large diameter. In this embodiment, the outer peripheral surface 8a has a small diameter at one end opening side of the electroformed portion 8 and a large diameter at the other end closing side. Moreover, in this embodiment, the outer peripheral surface 8a has a shape that expands in a tapered shape from one end opening side to the other end closing side.

  Hereinafter, an example of the manufacturing process of the bearing member 7 will be described with reference to FIGS.

  The bearing member 7 is, for example, a process of depositing and forming an electroformed part 8 that is an electroformed shell on the outer surface of the master 11 (electroforming process), and the mold of the molded part 9 using the electroformed part 8 and the master 11 as insert parts. It is manufactured through a process of forming (insert molding process) and a process of separating the electroformed part 8 and the master 11 in order.

  FIG. 3 conceptually shows an example of an electroforming process, and a master 11 (to be subjected to electroforming) in an electrolyte solution 13 (also referred to as an electroforming bath; the same applies hereinafter) filling the bathtub 12. A cathode) and an anode 14 are provided. The master 11 and the anode 14 are electrically connected to the power supply unit 15 via an electric wire or the like, and a predetermined voltage is applied between the electrodes 11 and 14 by the power supply unit 15.

The master 11 serving as a molding base of the electroformed part 8 is formed of, for example, stainless steel that has been subjected to quenching. In this embodiment, at least in the region where the electroformed part 8 is formed, it is formed so as to have a perfect cross-sectional contour and a uniform diameter in the axial direction. The material of the master 11 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. Master 11
When the shaft 2 is used as the shaft 2, in addition to the above characteristics, it is desirable that the material satisfies the mechanical strength, rigidity, slidability, heat resistance, etc. required as a component of the bearing. In this case, it is desirable to apply a surface treatment for reducing the frictional force with the electroformed part 8, for example, a fluorine-based resin coating, to at least a region where the electroformed part 8 is to be formed on the outer surface of the master 11.

The master 11 has a peeled shaft (solid shaft), a hollow shaft or other material (resin etc.) in the hollow portion.
It may be a solid shaft filled with. Further, the accuracy of the outer peripheral surface of the master 11 directly affects the surface accuracy of the inner peripheral surface 8c of the electroformed portion 8 that becomes the radial bearing surface of the bearing member 7, so that it is desirable to finish the master 11 as accurately as possible.

As shown in FIG. 3, a non-conductive masking portion 16 is formed in advance on the outer surface of the master 11 except for the region where the electroformed portion 8 is to be formed. As a material for forming the masking portion 16, a material having non-conductive properties and corrosion resistance to the electrolyte solution is selectively used.

As the electrolyte solution 13, a solution containing a metal (for example, Ni, Cu, or the like) that is a deposition material of the electroformed portion 8 is used. The kind of the deposited metal is appropriately selected according to required characteristics such as hardness or oil resistance required for the inner peripheral surface 8c serving as the radial bearing surface. In addition, the electrolyte solution 13 may contain a sliding material such as carbon or a stress relaxation material such as saccharin as necessary.

  In this embodiment, the anode 14 is a plate-like member whose inner peripheral surface has a shape (true cylindrical shape) imitating the outer peripheral surface 11a of the master 11, and a plurality of anodes 14 are arranged at equal intervals around the master 11 serving as a cathode. Established. In this case, the anode 14 is disposed in the bath in a state where the position and the angle with respect to the master 11 are adjusted such that the distance between the anode 14 and the master 11 is constant around the circumferential direction. Moreover, the anode 14 is arrange | positioned in a bath in the state which adjusted the position with respect to the master 11, especially an angle so that the opposing space | interval with the master 11 may differ in an axial direction. In this embodiment, the anode 14 is arranged in a state inclined at a predetermined angle with respect to the axis of the master 11 so that the distance between the master 11 and the master 11 is constant in the circumferential direction and varies primarily in the axial direction. .

From the above state, the power supply unit 15 applies a DC voltage to the master (cathode) 11 and the anode 14, and energizes the electrolyte solution 13 between the electrodes 11 and 14. Thereby, the ionized metal starts to be deposited on the outer peripheral surface 11 a of the master 11 in the region excluding the masking portion 16.

  Here, the electroforming is performed in a state where the facing distance between the master 11 and the anode 14 is varied in the axial direction. Therefore, as shown by the length of the arrow in FIG. 3, on the lower end side of the master 11 (side away from the masking portion 16), the facing distance between the two 11 and 14 is relatively narrow, so that the deposition rate increases, and the master 11 On the upper end side (side adjacent to the masking portion 16), the deposition rate is slow because the facing interval is relatively wide. Thereby, the electroformed part 8 formed by precipitation has a small diameter on the upper end side of the master outer peripheral surface 11a which becomes the opening side of the finished product (bearing member 7) and a large diameter on the lower end side of the outer peripheral surface 11a which becomes the closing side. It becomes.

  FIG. 4 shows an integrated product of the electroformed part 8 and the master 11 formed by the above-described electroforming process. As shown in the figure, the radial thickness of the electroformed part 8 is constant around the circumferential direction. On the other hand, in the axial direction, the thickness of the electroformed part 8 increases from the side adjacent to the masking part 16 (one end opening side) to the side separated from the other end closed side. In this embodiment, since the facing distance between the master 11 and the anode 14 is primarily increased from the one end opening side of the bearing member 7 toward the other end closing side, the anode 14 is disposed and electroforming is performed. The electroformed part 8 having a shape in which the outer peripheral surface 8a is expanded in a tapered shape is formed. In addition, in this embodiment, since the master 11 having a perfectly circular cross section and a constant diameter in the axial direction is used, the electroformed portion 8 having a shape in which the radial thickness increases primarily in the axial direction is formed. In this embodiment, the bottomed cylindrical electroformed part 8 is formed by performing electroforming on one end side of the master 11 including the end face.

  A master 11 (hereinafter, referred to as an electroformed shaft 17) provided with an electroformed part 8 on the outer periphery manufactured through the above steps is supplied and arranged as an insert part in a mold for insert molding the mold part 9. .

  FIG. 5 conceptually shows the insert molding process of the mold part 9. The pair of molding dies 18 and 19 used in this molding process is provided with a runner (not shown) and a gate 20, and when both the dies 18 and 19 are clamped, A cavity 21 is formed inside 19. In addition, an ejection mechanism for extruding the molded product and discharging it out of the mold is provided on the side of the molds 18 and 19 where the insert molded product remains when the mold is opened (in this embodiment, the movable mold 19). It is done. Specifically, a plurality of extrusion pins 22 are provided on one end opening side of the bearing member 7 (electroformed portion 8), and these extrusion pins 22 can be moved relative to the movable die 19 by a drive mechanism (not shown). It is configured. In this embodiment, the gate 20 is a dotted gate, and is formed at a position corresponding to the center of the bottom of the molding part 9 of the molding die (for example, the fixed mold 18). The gate area of each gate 20 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 having the above-described configuration, the movable mold 19 is brought close to the fixed mold 18 and clamped with the electroformed shaft 17 inserted in a predetermined position. Next, in a state where the mold is clamped, molten resin is injected and filled into the cavity 21 through the spool, the runner (both are not shown), and the gate 20, and the mold forming portion 9 is molded integrally with the electroformed shaft 17. To do. Thereby, the resin mold part 9 is formed in a shape that covers the outer surface of the electroformed part 8 (here, the outer peripheral surface 8a and the bottom lower end surface 8b).

  In addition, as a resin material, crystalline resins, such as LCP, PPS, PEEK, POM, PA, can be used conveniently, for example. Of course, these are merely examples, and any resin material including an amorphous resin can be selected as long as it is suitable for the application and use environment of the bearing. If necessary, a mixture of a plurality of resins other than those described above or other than the above can also be used. Alternatively, the properties can be improved by adding various fillers such as reinforcing materials (in any form such as fibers and powders), lubricants, and conductive agents.

  After the molding, the mold is opened, and the molded product in which the master 11, the electroformed part 8, and the molded part 9 are integrated is released from the movable mold 19. Specifically, after the mold is opened, the ejecting pin 22 of the ejection mechanism provided in one mold (here, the movable mold 19) is moved relative to the movable mold 19 toward the fixed mold 18 to thereby move the movable mold. The molded product remaining on the 19 side is pushed out to the fixed mold 18 side and discharged out of the mold. At this time, an extrusion trace having a shape following the end surface of the extrusion pin 22 may remain on the end surface 9 a on the one end opening side of the mold forming portion 9.

  In this case, the mold forming part 9 is formed integrally with the outer peripheral surface 8a of the electroformed part 8 located on the inner periphery thereof so as to face the portion whose outer diameter is enlarged. As shown, the molded part 9 is engaged with the electroformed part 8 in a direction to receive the pushing force by the pushing pin 22. Thereby, the coupling force (prevention force) between the electroformed part 8 and the mold forming part 9 is improved, and it is possible to prevent the mold forming part 9 from coming out of the electroformed part 8 at the time of ejection as much as possible. .

  Further, when the bearing member 7 is formed in a so-called cup shape as in this embodiment, the pushing force by the pushing pin 22 of the ejector mechanism pushes the die forming part 9 from the one end opening side of the electroformed part 8. Acts as follows. Therefore, if the electroformed part 8 is formed so as to have a larger diameter on the other end closing side than the one end opening side, the mold forming part 9 and the molded part 9 are directed toward the pushing direction of the ejector mechanism (the pushing pin 22). It is possible to engage the electroformed part 8 and improve the retaining force.

  As described above, during the electroforming process, only by appropriately adjusting the arrangement mode of the electrode (anode 14) with respect to the master 11, it is possible to improve the retaining force between the molded part 9 and the electroformed part 8 at the time of ejection. Therefore, it is not necessary to add another process such as a roughening process, and the cost increase can be suppressed.

  Moreover, in this embodiment, since the outer peripheral surface 8a of the electroformed part 8 is formed in a shape in which the diameter is increased in a tapered shape from one end opening side to the other end closing side, the mold forming part 9 is electroformed during ejection. Since the force received from the portion 8 is evenly distributed over the entire surface of the tapered outer peripheral surface 8a and the surface area can be increased, it is possible to further improve the retaining force. Or, since the radial direction thickness on the large diameter side of the electroformed part 8 does not have to be so large due to the improvement of the retaining force, the diameter of the bearing member 7 can be reduced. Further, if the outer peripheral surface 8a is tapered, as shown in FIG. 32, the anode 14 used to form the electroformed part 8 having a constant thickness is simply disposed in an inclined state with respect to the master 11. And can be adjusted very easily.

  Furthermore, in this embodiment, since the electroformed part 8 is formed in a bottomed cylindrical shape and the mold forming part 9 is formed so as to cover the lower end face 8b of the bottom part, the lower end face 8b of the electroformed part 8; Further strengthening of the retaining force is achieved by the coupling force with the bottom upper end surface 9b of the molded part 9 in contact with this surface. Further, if the mold forming portion 9 is formed in such a shape, a pin gate is sufficient as shown in the figure, so that the manufacturing cost of the mold can be reduced.

  Of course, since the inner peripheral surface 8c of the electroformed portion 8 is precisely transferred and formed following the outer peripheral surface 11a of the master 11, even if the outer peripheral surface 8a has a different diameter, it can be formed very precisely. Therefore, this inner peripheral surface 8c can be suitably used as a radial bearing surface.

  The molded product released as described above is separated into a bearing member 7 (see FIG. 2) including the electroformed portion 8 and the molded portion 9 and the master 11 in a subsequent separation step.

  In the separation step, for example, the inner peripheral surface 8 c of the electroformed part 8 is peeled from the outer peripheral surface 11 a of the master 11 by applying an impact to the master 11, the electroformed part 8, or the mold forming part 9. Thereby, the master 11 is pulled out from the electroformed part 8 and the die forming part 9, and the bearing member 7 as a finished product is obtained. In this embodiment, since the electroformed part 8 is formed to have a larger diameter on the other end closing side than on the one end opening side, when the master 11 is pulled out, for example, in the axial direction acting on the mold forming part 9 A sufficiently high coupling force (prevention force) can be given to the electroformed part 8 even with respect to the extraction force of the master 11 (for example, a binding force by a jig).

  Of course, the means for separating the electroformed part 8 is not limited to the above means, for example, a method in which the electroformed part 8 and the master 11 are heated (or cooled), and a difference in thermal expansion is generated between them, or A means using both means (impact and heating) in combination can also be used. In addition, the separation step can be performed simultaneously with the molding step of the mold forming unit 9, more precisely at the time of mold release by the ejector mechanism.

  For example, the shaft 2 provided with the rotor plate portion 3 is inserted into the inner periphery of the bearing member 7 formed as described above, and the outer peripheral surface 2a of the shaft 2 and the inner periphery of the electroformed portion 8 facing the outer peripheral surface 2a. Lubricating oil is poured into the radial gap (bearing gap 10) between the surface 8c from the atmosphere opening side (one end opening side). Thereby, the bearing device (fluid bearing device) 1 in which the bearing internal space including the bearing gap 10 is filled with the lubricating oil is completed.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to this embodiment and can adopt other configurations.

  For example, in the above embodiment, electroforming is performed by arranging the anode 14 so that the distance between the master 11 and the master 11 is constant around the circumferential direction, so that the outer diameter is constant around the circumferential direction. Although the case where the part 8 was formed was demonstrated, it is also possible to form the electroformed part 8 which makes shapes other than this. That is, at the time of electroforming, by changing the facing distance between the master 11 and the electrode (anode) around the circumferential direction, electroformed parts having different outer diameter dimensions around the circumferential direction (for example, an elliptical cross section or a polygonal cross section) It is possible to form a rotation stopper between the molded part and the mold forming part. For example, as shown in FIG. 7, by performing electroforming in a state in which three anodes 23 are arranged at an equal interval of 120 ° around the master 11, the shape indicated by the broken line in FIG. It is possible to deposit and form an electroformed part forming the following. Further, it is not necessary that portions of the electroformed portion 8 having relatively different outer diameter dimensions be provided over the entire axial length or the entire circumference of the outer peripheral surface 8a, as long as such different diameter portions are part of the outer peripheral surface 8a. Good.

  Further, when the electroformed part 8 has a shape other than the bottomed cylindrical shape, for example, when it has a cylindrical shape with openings at both ends, the problem of disconnection at the time of mold release or at the time of pulling out the master can be caused similarly. Therefore, even if the electroformed part is formed in a cylindrical shape with both ends open, the present invention is effectively applied to the retaining.

  Further, in the above embodiment, the case where the anode 14 is disposed around the master 11 to perform electroforming is described. However, as long as the facing distance between the electrodes 11 and 14 can be controlled to a predetermined value, for example, A method of performing electroforming with the master 11 disposed around the anode 14 is also possible. In this case, for example, the electroformed portion 8 can be formed by rotating the rack around the anode 14 while rotating the rack while holding the plurality of masters 11 in a jig called a rack. Of course, in this case as well, it is preferable that the position and the inclination angle of the anode 14 are appropriately determined so that the outer diameter (thickness) of the electroformed portion 8 is different in the axial direction.

  In the above-described embodiment, the eject mechanism is configured by a plurality of push pins 22, but is not limited thereto. In consideration of the extrusion area of the molded product, for example, one extrusion pin having an annular extrusion surface can be used. Further, this type of ejection mechanism does not necessarily have to be provided on the movable mold 19 side, and in consideration of the form of the mold forming portion 9 (or bearing member 7) to be insert-molded, the side on which the molded product remains when the mold is opened It is important to install in

  Moreover, in the above embodiment, although the case where resin was used as a material of the shaping | molding part 9 was demonstrated, it is also possible to shape | mold the shaping | molding part 9 by filling the metal in the cavity 21 and solidifying. In this case, a metal having a melting point lower than that of the electroformed metal can be used.

  Moreover, although the case where the special sealing means was not provided in the one end opening side of the bearing member 7 was illustrated in the said embodiment, it is not restricted to this but arbitrary sealing means can be arrange | positioned. For example, an electroformed part is formed by using a master 11 having a tapered surface on the master 11, and a seal space is formed between the outer peripheral surface 2a of the shaft 2 with a tapered surface formed on the inner peripheral surface of the electroformed part. It can also be formed. Alternatively, the seal space may be formed by the inner peripheral surface of the molded part 9 by devising the shape of the cavity 21 and the arrangement of the electroformed shaft 17.

  Moreover, although the said embodiment demonstrated the case where a perfect circle bearing was comprised between the axis | shaft 2 and the bearing member 7 which rotationally supports this, bearings other than this can also be comprised. For example, a dynamic pressure generating portion for generating a fluid dynamic pressure action is provided on either the inner peripheral surface 8c of the electroformed portion 8 or the outer peripheral surface 2a of the shaft 2 when facing the inner peripheral surface 8c. Thus, a dynamic pressure bearing can be configured. In this case, the shape of the dynamic pressure generating portion constituting the dynamic pressure bearing is not limited. For example, although illustration is omitted, a region in which a plurality of axial grooves extending in the axial direction are arranged at equal intervals in the circumferential direction can be formed. It is also possible to form a so-called multi-arc bearing in which a plurality of arc surfaces are formed and the radial gap between the arc surfaces and the surfaces facing the arc surfaces is reduced in a wedge shape in the circumferential direction. . Alternatively, it is possible to form a region in which a plurality of grooves (dynamic pressure grooves) inclined with respect to the axial direction are arranged in a herringbone shape. These dynamic pressure generating portions may be provided on the outer peripheral surface 2 a side of the shaft 2 in addition to the inner peripheral surface 8 c side of the bearing member 7.

  In the above embodiment, the shaft 2 is pivotally supported by the upper end surface 8d at the bottom of the electroformed part 8, but in this case as well, one end surface 2b of the shaft 2 or the upper end surface 8d of the electroformed part 8 is illustrated. It is possible to provide a dynamic pressure generating portion on at least one of these and to constitute a thrust dynamic pressure bearing between both surfaces 2b and 8d. In this case, as the shape that the thrust dynamic pressure generating portion can take, in addition to the above-mentioned herringbone shape, a configuration in which a plurality of dynamic pressure generating grooves are arranged in a spiral shape or step shape, or a configuration having wave-shaped unevenness Any form can be adopted. Of course, the dynamic pressure generating portion can be provided at an arbitrary position depending on the shape of the bearing member 7 or the shaft 2 regardless of radial or thrust.

  In the above embodiment, the lubricating oil is exemplified as the fluid that is supplied to the radial bearing gap and the thrust bearing gap formed in the bearing device 1 and generates a fluid film in the bearing gap. For example, a fluid such as a gas such as air, a fluid lubricant such as a magnetic fluid, or lubricating grease may be used. Alternatively, if the bearing device 1 is used as a sliding bearing device, it is not always necessary to fill the inside of the bearing with the fluid, and only a necessary minimum amount may be supplied.

  Further, in this embodiment, the case where the shaft 11 is manufactured separately from the master 11 and the shaft-shaped member having the rotor plate portion 3 attached to one end thereof is used as the shaft 2 is described. However, the master 11 is used as the shaft 2 as it is. It is also possible.

  The bearing device of the present invention is not limited to the above examples, and can be widely applied to support the rotating shaft of the drive mechanism. Among them, this bearing device has a high coupling force with respect to the die forming portion 9 of the electroformed portion 8 and a high-precision bearing surface as described above. The present invention can be suitably used for small motors for information equipment that require high rotational accuracy even under high-speed rotation, such as spindle motors for spindles, and spindle motors for driving magneto-optical disks for optical disks.

It is sectional drawing of the motor provided with the bearing apparatus which concerns on one Embodiment of this invention. It is sectional drawing of a bearing apparatus. It is a figure which shows notionally an example of an electroforming process. It is a partial cross section perspective view of an electroformed shaft. It is a figure which shows notionally an example of the molding process of a bearing member. It is a figure which shows notionally the movement of the metal mold | die at the time of ejection. It is a figure which shows notionally the other example of an electroforming process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bearing apparatus 2 Shaft 2a Outer peripheral surface 6 Fan 7 Bearing member 8 Electroformed part 8a Outer peripheral surface 8c Inner peripheral surface (radial bearing surface)
9 Molding portion 9a One end opening side end face 10 Bearing gap 11 Master 11a Outer peripheral face 14 Anode 18 Fixed mold 19 Movable mold 22 Extrusion pin 23 Anode

Claims (5)

In a bearing member provided with an electroformed part provided with a separation surface from the master on the inner periphery, and a mold part that is located outside the electroformed part and is formed integrally with the electroformed part,
The outer diameter of the electroformed part is reduced in the direction of pulling out the master from the electroformed part by changing the thickness of the electroformed part in the axial direction to make the outer peripheral surface tapered. Bearing member.   The bearing member according to claim 1, wherein an outer diameter dimension of an electroformed portion on an ejector side provided in the molding die is reduced.   The bearing member according to claim 1, wherein one end of the electroformed part is opened and the other end is closed, and the outer diameter of the electroformed part is larger on the other end closed side than on the one end open side.   The bearing member according to claim 1, wherein the outer diameter dimension of the electroformed part is varied in the axial direction by performing electroforming in a state in which the distance between the electrodes is controlled. A bearing member according to any one of claims 1 to 4 and a shaft inserted in an inner periphery of the bearing member, wherein a lubricating fluid is supplied between an inner peripheral surface of the electroformed part and an outer peripheral surface of the shaft. A bearing device characterized in that a radial gap is formed.

Images