JP6189065B2 - Fluid dynamic bearing device and assembly method thereof - Google Patents

Description

  The present invention relates to a fluid dynamic pressure bearing device that supports an inner member in a relatively rotatable manner by a dynamic pressure action of lubricating oil generated in a bearing gap between the inner member and the outer member, and an assembling method thereof.

  A motor mounted on an electric device such as a ventilation fan incorporates a bearing, and the rotation shaft is supported by the bearing so as to be relatively rotatable. As this type of bearing, a so-called rolling bearing comprising an outer ring, an inner ring, a plurality of rolling elements interposed therebetween, and a cage for holding the plurality of rolling elements is generally used ( For example, Patent Document 1).

  For example, a small ventilation fan installed in a house, especially a small ventilation fan provided in a 24-hour ventilation system, is required to be low in cost, but the rolling bearing is composed of many parts as described above. Therefore, there is a limit to cost reduction. Moreover, since the ventilation fan of the said system is fundamentally operated continuously, it is calculated | required that it is especially low noise. However, rolling bearings avoid the generation of so-called cage noise caused by collision between the cage pocket and rolling elements during operation, and friction noise caused by rolling of the rolling elements on the raceway surface of the inner and outer rings. Since it is not possible, it is difficult to meet the demand for further improvement in quietness.

  In view of the above circumstances, a fluid dynamic pressure bearing may be used as a bearing incorporated in a motor such as a ventilation fan. For example, as shown in FIG. 12, the fluid dynamic pressure bearing device disclosed in Patent Document 2 includes an inner member 101, and an outer member 102 that surrounds the outer peripheral surface 101 a and both end surfaces 101 b and 101 c of the inner member 101. The space between the inner member 101 and the outer member 102 is filled with lubricating oil. When the inner member 101 rotates, a radial bearing gap R ′ is formed between the outer peripheral surface 101a of the inner member 101 and the inner peripheral surface 102a of the outer member 102, and both axial end surfaces of the inner member 101 Thrust bearing gaps T ′ are formed between 101b and 101c and the inner end faces 102b and 102c of the outer member 102, respectively, and the dynamic pressure generated in the lubricating oil in these radial bearing gaps R ′ and thrust bearing gaps T ′. The inner member 101 is rotatably supported. Thus, by replacing the rolling bearing with a fluid dynamic pressure bearing, the cost is reduced by reducing the number of parts and the quietness is improved.

JP 2000-249142 A JP 2011-231874 A

  In Patent Document 1, as shown in FIG. 12, an outer member 102 is configured by combining a first outer member 110 and a second outer member 120 having an L-shaped cross section. When assembling the outer member 102, the cylindrical portion 111 of the first outer member 110 and the cylindrical portion 121 of the second outer member 120 are fitted together, and an adhesive is injected between them. It is fixed by that. In this case, it is necessary to hold the first outer member 110 and the second outer member 120 until the adhesive is cured. In Patent Document 1, as shown in FIG. 13, protrusions 130 are provided at a plurality of circumferential positions on the outer peripheral surface of the first outer member 110, and the cylindrical inner periphery of the second outer member 120 facing the protrusion 130. Both are temporarily fixed by press-fitting into the surface.

  However, when the protrusions 130 are press-fitted, the cylindrical portion 111 of the first outer member 110 is deformed in the diameter reducing direction, leading to a decrease in accuracy of the radial bearing surface, or the cylindrical portion 121 of the second outer member 120 is expanded. There is a possibility that the assembly to other members may be deteriorated due to deformation in the radial direction. In addition, by pressing the first outer member 110 and the second outer member 120, shavings are generated, and the shavings fall to the surroundings or are mixed into the lubricating oil inside the bearing as contamination, thereby reducing the bearing performance. There is a risk of letting

  In order to avoid the above problems, the first outer member 110 and the second outer member 120 may be fitted through a gap, and both may be bonded and fixed in this state (gap adhesion). However, in this case, since it is necessary to hold the first outer member 110 and the second outer member 120 with a jig until the adhesive is cured, another assembly is required to assemble the next outer member during this time. Tools are required. Therefore, when the fluid dynamic bearing device is mass-produced by such a method, an enormous number of jigs are required, and the production cost increases.

  In view of the above circumstances, an object of the present invention is to facilitate assembly of a fluid dynamic bearing device without causing deformation of an outer member, generation of shavings, and cost increase.

  For example, if the first outer member and the second outer member are fixed using an adhesive having a high curing speed (for example, an instantaneous adhesive), the first outer member and the second outer member are held by a jig. Since it is possible to reduce the time required for the jig, the number of jigs can be reduced. However, since the lubricating oil is filled between the outer member and the inner member, the radial direction between the outer peripheral surface of the cylindrical portion of the first outer member and the inner peripheral surface of the cylindrical portion of the second outer member. It is necessary to completely seal the gap with an adhesive to prevent the lubricant from leaking out. However, instant adhesives are often inferior in their ability to completely fill the gap and seal (sealing performance). The above-mentioned radial gap cannot be completely sealed, and oil leakage may occur.

  Therefore, a fluid dynamic pressure bearing device according to the present invention includes an annular inner member, a cylindrical portion that faces the outer peripheral surface of the inner member in the radial direction, and one axial end surface of the inner member in the axial direction. The 1st outer member which has a flat plate part which opposes, the cylindrical part fixed to the outer peripheral surface of the cylindrical part of the 1st outer member, and the flat plate part which faces the other axial end face of an inner member in the axial direction A radial bearing gap formed between the inner peripheral surface of the cylindrical portion of the first outer member and the outer peripheral surface of the inner member, and one end surface in the axial direction of the inner member. A thrust bearing gap, a radial bearing gap and a thrust formed between the flat plate portion of the first outer member and between the other axial end surface of the inner member and the flat plate portion of the second outer member. Lubricating oil interposed in the bearing gap, the outer peripheral surface of the cylindrical portion of the first outer member and the cylindrical portion of the second outer member A first adhesive that temporarily fits the first outer member and the second outer member into the radial gap, and a radial gap is fitted into the peripheral surface without being press-fitted through the radial gap. A second adhesive that completely seals is interposed.

  In this fluid dynamic pressure bearing device, an inner member is arranged between the first outer member and the second outer member in the axial direction, and the outer peripheral surface of the cylindrical portion of the first outer member and the second outer member are arranged. The first outer member in a state in which the inner circumferential surface of the cylindrical portion is fitted through the radial gap without press fitting, and the gap widths of the first thrust bearing gap and the second thrust bearing gap are set. And the second outer member can be assembled by sequentially performing a step of temporarily fixing the second outer member with the first adhesive and a step of completely sealing the radial gap with the second adhesive.

  As described above, by causing the first outer member and the second outer member to be fitted through the radial gap without press-fitting, deformation due to press-fitting and generation of shavings can be avoided. In addition, since the first adhesive that temporarily fixes the first outer member and the second outer member does not require sealing properties, an adhesive having a short curing time (for example, an instantaneous adhesive) can be used. In this manner, the first outer member and the second outer member are temporarily fixed with an instantaneous adhesive or the like to hold the first outer member and the second outer member in a state where the thrust bearing gap is set. Since the time, that is, the time for using the jig can be shortened, the number of jigs used in mass production can be reduced. At this time, if the curing accelerator is applied to the first adhesive supplied to the radial gap between the first outer member and the second outer member, the curing time of the first adhesive is further shortened, The time for holding the first outer member and the second outer member with the jig can be further shortened. Furthermore, by temporarily fixing the first outer member and the second outer member, the second adhesive that is subsequently filled into the radial gap has no limitation on the curing time, and has excellent sealing properties. Therefore, the radial gap can be completely sealed.

  As the first adhesive, for example, a cyanoacrylate-based instantaneous adhesive or an anaerobic adhesive can be used. As the second adhesive, for example, an epoxy-based adhesive or an ultraviolet curable adhesive can be used.

  The radial gap between the first outer member and the second outer member is preferably in the range of 30 to 100 μm. When the radial gap is less than 30 μm, it is difficult to fill the adhesive, and when the radial gap exceeds 100 μm, temporary fixing with the first adhesive is difficult.

  A first gap and a second gap having different sizes are provided in a radial gap between the first outer member and the second outer member, and the first adhesive is disposed in the first gap, and the second gap If a 2nd adhesive agent is distribute | arranged to, a 1st clearance gap and a 2nd clearance gap can be set to the magnitude | size suitable for a 1st adhesive agent and a 2nd adhesive agent, respectively. For example, the first adhesive preferably has a short curing time, but since such adhesives often have poor sealing properties, the first gap is preferably relatively small. Further, since many second adhesives have high viscosity, it is preferable that the second gap is relatively large. From the above, it is preferable that the first gap is smaller than the second gap.

  For example, when the first adhesive is applied and temporarily fixed to the end portion on the air opening side of the radial gap between the first outer member and the second outer member, the cured first adhesive becomes an obstacle. Therefore, the supply of the second adhesive to the radial gap may be hindered. Therefore, if the first adhesive is disposed on the closed side of the radial gap and the second adhesive is filled on the air opening side with respect to the first adhesive, the above-described problem can be avoided.

  As described above, according to the present invention, the assembly of the fluid dynamic pressure bearing device can be facilitated without causing deformation of the outer member, generation of shavings, and cost increase.

It is a longitudinal cross-sectional view of the bearing unit for ventilation fan motors. 1 is a longitudinal sectional view of a fluid dynamic bearing device according to an embodiment of the present invention. (A) is the side view which looked at the inward member from A direction of FIG. 2, (b) is the side view seen from the B direction, (c) is the side view seen from the C direction. FIG. 3 is an enlarged view of FIG. 2. It is sectional drawing which shows the assembly method of the said fluid dynamic pressure bearing apparatus. It is sectional drawing which shows the assembly method of the said fluid dynamic pressure bearing apparatus. It is sectional drawing which shows the assembly method of the said fluid dynamic pressure bearing apparatus. It is sectional drawing which shows the assembly method of the said fluid dynamic pressure bearing apparatus. It is an expanded sectional view of the fluid dynamic bearing device concerning other embodiments. It is an expanded sectional view of the fluid dynamic bearing device concerning other embodiments. It is sectional drawing of the fluid dynamic pressure bearing apparatus which concerns on other embodiment. It is sectional drawing of the conventional fluid dynamic pressure bearing apparatus. It is sectional drawing in the XX line of FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an axial sectional view of a bearing unit 1 incorporating a fluid dynamic bearing device 4 according to an embodiment of the present invention. The bearing unit 1 is used, for example, by being incorporated in a small ventilation fan motor (more strictly speaking, an inner rotor type motor for a ventilation fan) of a 24-hour ventilation system installed in a living room of a house. The bearing unit 1 is a motor rotor for rotatably supporting a rotating body including a rotating shaft 2, a motor rotor 3 fixed to the outer peripheral surface of the rotating shaft 2, and a fan 6 provided at an end of the rotating shaft 2. 3, and a pair of fluid dynamic bearing devices 4, 4 disposed between the rotating shaft 2 and the housing 5. A spring 7 is disposed in a compressed state between the fluid dynamic bearing device 4 and the housing 5 on one axial side (the right side in the figure). The stator is not shown.

  As shown in FIG. 2, the fluid dynamic bearing device 4 includes an inner member 10 and an outer member 20 that rotatably supports the inner member 10. The inner member 10 has an inner peripheral surface 13 fixed to the outer peripheral surface of the rotary shaft 2 by press-fitting or bonding (see FIG. 1). The outer member 20 is attached so that the outer peripheral surface 22a2 is fitted to the inner peripheral surface of the housing 5 and is slidable in the axial direction (see FIG. 1). Lubricating oil is interposed between the surfaces of the inner member 10 and the outer member 20 (radial bearing gap R and thrust bearing gap T) facing each other in the axial direction and the radial direction (see FIG. 2). Note that the fluid dynamic bearing devices 4 and 4 in FIG. 1 have the same structure.

  The inner member 10 has an annular shape and is formed of a metal, for example, a sintered metal. The inner member 10 includes a substantially cylindrical bearing portion 10a having a substantially rectangular cross section, a substantially cylindrical fixing portion 10b provided on the inner periphery of the bearing portion 10a and fixed to the outer peripheral surface of the rotary shaft 2. Have In the present embodiment, the bearing portion 10a and the fixed portion 10b are integrally formed. In FIG. 2, a conceptual boundary between the bearing portion 10a and the fixed portion 10b is indicated by a dotted line.

  The outer peripheral surface 11 of the bearing portion 10a of the inner member 10 forms a cylindrical surface, and this surface functions as a radial bearing surface. A dynamic pressure groove 11a is formed on the outer peripheral surface 11 of the bearing portion 10a. In the present embodiment, for example, a herringbone-shaped dynamic pressure groove 11 a as shown in FIG. 3B is formed on the entire outer peripheral surface 11. The dynamic pressure groove 11a is formed by rolling, for example. In this embodiment, since the inner member 10 is formed of sintered metal, the plastic flow of the outer peripheral surface 11 of the inner member 10 due to compression of the rolling process can be absorbed by the internal pores of the sintered metal. For this reason, the rise of the surface of the inner member 10 due to plastic flow is suppressed, and the dynamic pressure groove 11a can be formed with high accuracy. In addition, in FIG.3 (b), the hill part between the dynamic-pressure grooves 11a is shown by cross hatching.

  End surfaces 12 on both axial sides of the bearing portion 10a of the inner member 10 extend in a direction orthogonal to the axial direction, and these surfaces function as thrust bearing surfaces. Dynamic pressure grooves 12a are formed on the end faces 12 on both axial sides of the bearing portion 10a. In this embodiment, for example, as shown in FIGS. 3A and 3C, a herringbone-shaped dynamic pressure groove 12 a is formed on the entire end surface 12. In this embodiment, since the inner member 10 is formed of a sintered metal, the dynamic pressure groove 12a can be formed with high accuracy by pressing. The dynamic pressure groove 12a can be molded simultaneously with the sizing of the inner member 10 made of sintered metal, for example. 3A and 3C, the hill portion between the dynamic pressure grooves 12a is indicated by cross hatching.

  The fixed portion 10b protrudes outward in the axial direction from the end surfaces 12 on both axial sides of the bearing portion 10a, and the outer peripheral surface 14 of the protruding portion faces the inner diameter end of the outer member 20 in the radial direction. The inner peripheral surface 13 of the fixed portion 10 b is fixed to the outer peripheral surface of the rotating shaft 2.

The inner member 10 is formed of, for example, a copper iron-based sintered metal, and in this embodiment, the inner member 10 is formed of a copper iron-based sintered metal with a copper blending ratio of 20 to 80%. If the copper content is less than 20%, there will be a problem with the formability and lubricity of the dynamic pressure groove. On the other hand, if the copper content exceeds 80%, the iron content will be too low and wear resistance may be insufficient. Because there is. Moreover, the outer peripheral surface 11 which forms a radial bearing surface at least among the inward members 10 makes the surface opening rate of a sintered member 2-20%. When the surface opening ratio is less than 2%, the circulation of the lubricating oil is not sufficient, and when the surface opening ratio exceeds 20%, the pressure of the lubricating oil decreases. Further, the density of the inner member 10 is set to 6 to 8 g / cm ³ in order to maintain the communication property and plastic workability of the lubricating oil.

  As shown in FIG. 2, the outer member 20 includes an annular first outer member 21 and second outer member 22 having an L-shaped cross section. The first outer member 21 integrally includes a cylindrical portion 21a and a flat plate portion 21b extending from the one axial end of the cylindrical portion 21a (the right end in FIG. 2) to the inner diameter side. The second outer member 22 integrally includes a cylindrical portion 22a and a flat plate portion 22b extending from the other axial end of the cylindrical portion 22a (the left end in FIG. 2) to the inner diameter side. In the present embodiment, for example, the first outer member 21 and the second outer member 22 are formed by pressing a metal plate. A stainless steel plate, a cold-rolled steel plate, etc. can be used for a metal plate, The plate | board thickness is about 0.1-1 mm.

  As shown in FIG. 4, the outer peripheral surface 21a2 of the cylindrical portion 21a of the first outer member 21 and the inner peripheral surface 22a1 of the cylindrical portion 22a of the second outer member 22 are not press-fitted in any place, It fits via the radial clearance P. In the illustrated example, the outer peripheral surface 21a2 of the first outer member 21 and the inner peripheral surface 22a1 of the second outer member 22 are both smooth cylindrical surfaces, and the radial gap P is constant in the axial direction. The size of the radial gap P is set in a range of 30 to 100 μm, for example.

  The first adhesive Q1 and the second adhesive Q2 are interposed in the radial gap P. The first adhesive Q1 is for temporarily fixing the first outer member 21 and the second outer member 22. As the first adhesive Q1, a material having a short curing time is used. However, if the curing time is too short, the working time required for setting a thrust bearing gap, which will be described later, cannot be secured. Those that do not are preferred. Specifically, as the first adhesive Q1, for example, an instantaneous adhesive (cyanoacrylate adhesive), an anaerobic adhesive, an ultraviolet curable adhesive, or the like is used. The second adhesive Q2 completely seals the entire circumference of the radial gap P. As the second adhesive Q2, one having excellent sealing properties can be used. For example, a material that undergoes volume shrinkage upon curing may not be able to completely seal the radial gap P, so that the second adhesive preferably does not cause volume shrinkage. Further, since the gap width of the actual radial gap P is not completely uniform, if the viscosity of the second adhesive Q2 is too low, the second adhesive moves to the narrow gap side due to capillary action, and the radial gap P may not be completely sealed. Accordingly, the second adhesive Q2 is preferably one having a relatively high viscosity (for example, 2800 cp or more (23 ° C., 50 rpm / cp)). Specifically, for example, an epoxy adhesive or an ultraviolet curable adhesive can be used as the second adhesive Q2. In the present embodiment, a cyanoacrylate adhesive is used as the first adhesive Q1, and an epoxy adhesive is used as the second adhesive Q2. The first adhesive Q1 is disposed, for example, at a plurality of locations separated in the circumferential direction, and is disposed closer to the closed side (left side in FIG. 4) of the radial gap P than the second adhesive Q2. In addition, the arrangement | positioning location of the 1st adhesive agent Q1 and the 2nd adhesive agent Q2 is not restricted above, For example, you may distribute | arrange the 1st adhesive agent Q1 to a perimeter.

  As shown in FIG. 2, the inner peripheral surface 21a1 of the cylindrical portion 21a of the first outer member 21 is formed as a smooth cylindrical surface and functions as a radial bearing surface. The inner end surface 21b1 of the flat plate portion 21b of the first outer member 21 and the inner end surface 22b1 of the flat plate portion 22b of the second outer member 22 are formed as smooth flat surfaces, and each function as a thrust bearing surface. A radial bearing gap R is formed between the inner peripheral surface 21 a 1 (radial bearing surface) of the outer member 20 and the outer peripheral surface 11 (radial bearing surface) of the bearing portion 10 a of the inner member 10. Thrust bearing gaps T are formed between the inner end surfaces 21b1 and 22b1 (thrust bearing surfaces) and both end surfaces 12 (thrust bearing surfaces) of the bearing portion 10a of the inner member 10, respectively.

  The inner diameter end of the flat plate portion 21 b of the first outer member 21 and the inner diameter end of the flat plate portion 22 b of the second outer member 22 have an appropriate radial clearance from the outer peripheral surface 14 of the fixed portion 10 b of the inner member 10. Opposite. In the illustrated example, tapered surfaces 21b2 and 22b2 having diameters increased outward in the axial direction are formed at the inner diameter ends of the flat plate portions 21b and 22b, and between the tapered surfaces 21b2 and 22b2 and the outer peripheral surface 14 of the fixing portion 10b. A wedge-shaped seal space S is formed. The seal space S prevents leakage of the lubricating oil. Furthermore, if an oil repellent is applied to the end surface 15 of the fixed portion 10b of the inner member 10 and the outer end surface of the outer member 20 (the outer end surfaces of the flat plate portions 21b and 22b), oil leakage from the seal space S can be ensured. Can be prevented.

  The internal space of the fluid dynamic bearing device 4 having the above configuration is filled with lubricating oil including the internal pores of the sintered metal inner member 10. As shown in FIG. 2, the lubricating oil is filled in the gap between the inner member 10 and the outer member 20, and the outer diameter side (radial bearing gap R side) is generated by the capillary force of the thrust bearing gap T and the seal space S. ). The oil surface of the lubricating oil is held in the thrust bearing gap T or the seal space S.

  When the rotating shaft 2 rotates, the pressure of the oil film in the radial bearing gap R of each fluid dynamic bearing device 4 is increased by the dynamic pressure groove 11a, and the rotating shaft 2 and the inner member 10 are moved outward by the dynamic pressure action of the oil film. The member 20 is supported in a non-contact manner in the radial direction. At the same time, the pressure of the oil film in the thrust bearing gap T of each fluid dynamic pressure bearing device 4 is increased by the dynamic pressure groove 12a, so that the rotary shaft 2 and the inner member 10 are in both thrust directions with respect to the outer member 20. Non-contact support (see FIG. 2).

  When a dynamic pressure action occurs in the lubricating oil in the thrust bearing gap T, the outer member 20 of the fluid dynamic pressure bearing device 4 on the right side in the figure slides to the right side in the figure to compress the spring 7, thereby both fluid dynamic pressures. The thrust bearing gap T of the bearing devices 4 and 4 is ensured. Thus, the thrust bearing gap T can be set with high accuracy by fitting the outer member 20 to the housing 5 so as to be movable in the axial direction. Thereby, the inner member 10 is reliably non-contact supported with respect to the outer member 20, and generation | occurrence | production of the noise by contact sliding can be prevented more reliably.

  Next, a method for assembling the fluid dynamic bearing device 4 will be described.

  As shown in FIG. 5, the jig 30 used in this assembling method includes a fixing jig 31 and a moving jig 32 that is arranged inside the fixing jig 31 and is movable in the vertical direction. The fixing jig 31 has a mounting surface 31a, a guide surface 31b, and an inner peripheral surface 31c that is slidably fitted to the moving jig 32. The moving jig 32 has an outer peripheral surface 32c that is slidably fitted to the shoulder surface 32a, the guide surface 32b, and the fixing jig 31.

  First, the flat plate portion 22b of the second outer member 22 is inserted downward into the guide surface 31b of the fixing jig 31, and the flat plate portion 22b is placed in contact with the mounting surface 31a. Thereafter, the inner peripheral surface 13 of the inner member 10 is fitted to the guide surface 32 b of the moving jig 32, and the inner member 10 is inserted into the inner periphery of the second outer member 22. The lower end surface 12 of the portion 10 a is brought into contact with the inner end surface 22 b 1 of the flat plate portion 22 b of the second outer member 22. At this time, the shoulder surface 32 a of the moving jig 32 is positioned below the lower end surface 15 of the fixed portion 10 b of the inner member 10.

  Thereafter, as shown in FIG. 6, the moving jig 32 is raised, and the shoulder surface 32 a of the moving jig 32 is brought into contact with the lower end surface 15 of the fixed portion 10 b of the inner member 10. With this position as a reference position, the moving jig 32 is further raised to separate the inner member 10 from the second outer member 22 and stopped at a position where the total amount Δ of both thrust bearing gaps T is reached. Maintain state.

  Next, as shown in FIG. 7, the first outer member 21 is assembled to the second outer member 22. At this time, the first adhesive Q1 is applied in advance to the outer peripheral surface 21a2 of the cylindrical portion 21a of the first outer member 21. In this embodiment, the 1st adhesive agent Q1 is apply | coated to the some location spaced apart in the circumferential direction a little below the axial direction center among the outer peripheral surfaces 21a2 of the cylindrical part 21a (illustration omitted). Thus, the outer circumferential surface 21a2 of the cylindrical portion 21a of the first outer member 21 to which the first adhesive Q1 is applied is not pressed into the inner peripheral surface 22a1 of the cylindrical portion 22a of the second outer member 22, and a radial gap is formed. When the lower end surface 21b1 of the flat plate portion 21b comes into contact with the upper end surface 12 of the bearing portion 10a of the inner member 10, the setting of the thrust bearing gap T is completed. If the first adhesive Q1 is cured before the setting of the thrust bearing gap T is completed, the operation is hindered. Therefore, the first adhesive Q1 has a setting time that can secure the setting work time of the thrust bearing gap T. Those having (for example, 60 seconds or more) are used. In addition, by using the first adhesive Q1 having a viscosity of 800 mPa · sec or more, the first adhesive Q1 hangs down and adheres to the radial bearing surface or the thrust bearing surface, and the thrust bearing gap T It is possible to prevent the first adhesive Q1 from being cured before the setting is completed.

  Thus, the first adhesive Q1 interposed in the radial gap P between the cylindrical portion 21a of the first outer member 21 and the cylindrical portion 22a of the second outer member 22 in a state where the thrust bearing gap T is set. The first outer member 21 and the second outer member 22 are temporarily fixed by curing. In the present embodiment, the curing of the first adhesive Q1 is promoted by applying a curing accelerator to the first adhesive Q1 interposed in the radial gap P. As a result, even the first adhesive Q1 having a relatively long curing time can be used. The curing accelerator is dropped from a plurality of locations (for example, two locations facing each other in the diametrical direction) separated in the circumferential direction among the end portions (the upper end in FIG. 7) of the radial gap P on the atmosphere opening side. As a hardening accelerator, what contains 0.1-30% of aromatic amines as a hardening acceleration | stimulation component can be used, for example. As a solvent for the curing accelerator, a highly volatile organic solvent such as acetone can be used. In this way, by adjusting the components of the curing accelerator and managing the volatilization time, it is possible to prevent a situation where the first adhesive Q1 protrudes from the first gap P1 before it cures and goes around to the radial bearing surface or the thrust bearing surface. Can do.

  When the first adhesive Q1 is cured and the first outer member 21 and the second outer member 22 are temporarily fixed, the sub-assembly including the inner member 10 and the outer member 20 is removed from the jig 30. Thus, by temporarily fixing the first outer member 21 and the second outer member 22 and removing them from the jig 30, the usage time of the jig 30 in the manufacturing process of each product is shortened. It can be used in the assembly process of the next product (fluid dynamic bearing device 4). As a result, the number of jigs 30 used in mass production can be reduced, and the production cost can be reduced.

  Thereafter, as shown in FIG. 8, the nozzle is formed in the radial gap P between the outer peripheral surface 21 a 2 of the cylindrical portion 21 a of the first outer member 21 and the inner peripheral surface 22 a 1 of the cylindrical portion 22 a of the second outer member 22. The second adhesive Q2 is injected from 40 to completely seal the radial gap P. At this time, by providing the tapered surface 22a3 at the end of the cylindrical portion 22a of the second outer member 22, the injection of the second adhesive Q2 is facilitated. Then, the second adhesive Q2 is solidified by firing together with the subassembly. In addition, baking is unnecessary when the 2nd adhesive agent Q2 is an anaerobic adhesive agent.

  Lubricating oil is injected between the inner member 10 and the outer member 20 assembled as described above, including the internal pores of the inner member 10 made of sintered metal. After that, the fluid dynamic pressure bearing device 4 is heated to a set temperature exceeding the maximum temperature (upper limit) assumed in the usage environment, and the lubricating oil overflowing from the seal space S due to thermal expansion at this time is wiped off. Thereafter, the lubricating oil contracts by cooling to room temperature, and the oil surface is retracted to the bearing inner side (outer diameter side) and held in the vicinity of the inner diameter side end of the thrust bearing gap T or in the seal space S. Thereby, if it is in the assumed temperature range, lubricating oil will not leak by thermal expansion. Thus, the fluid dynamic bearing device 4 is completed.

  The present invention is not limited to the above embodiment. Hereinafter, although other embodiment of this invention is described, the same code | symbol is attached | subjected to the location which has the function similar to said embodiment, and duplication description is abbreviate | omitted.

  In the above embodiment, the case where the first adhesive Q1 is disposed closer to the closed side (the left side in FIG. 4) of the radial gap P than the second adhesive Q2 is shown, but the present invention is not limited thereto. For example, as shown in FIG. 9, the first adhesive Q1 is disposed at a plurality of locations in the circumferential direction at the end portion (right end in the drawing) of the radial gap P on the atmosphere opening side, and the second adhesive is disposed closer to the closing side than this. Q2 may be arranged. In this case, since it is necessary to inject the second adhesive Q2 into the radial gap P after the first adhesive Q1 is cured at the end of the radial gap P on the atmosphere opening side, the cured first adhesive There is a possibility that the operation of injecting the second adhesive Q2 may be hindered by Q1 being in the way. Therefore, from the viewpoint of workability, it is preferable to fill the second adhesive Q2 closer to the atmosphere release side than the first adhesive Q1 as in the above embodiment.

  In the above embodiment, as shown in FIG. 4, the gap width of the radial gap P between the outer peripheral surface 21 a 2 of the first outer member 21 and the inner peripheral surface 22 a 1 of the second outer member 22 is an axis. Although the case where the direction is constant is shown, the present invention is not limited to this, and for example, as shown in FIG. 10, a first gap P1 and a second gap P2 having different gap widths may be provided. In this case, by arranging the first adhesive Q1 in the first gap P1 and arranging the second adhesive Q2 in the second gap P2, the first gap P1 and the second gap P2 are respectively changed to the first adhesive Q1. And it can set to the magnitude | size suitable for the 2nd adhesive agent Q2. For example, since the first adhesive Q1 is often inferior in sealing performance, the first gap P1 is preferably small, and the second adhesive Q2 is often viscous and difficult to enter the gap, so the second gap P2 Is preferably somewhat large. Accordingly, the first gap P1 is preferably smaller than the second gap P2. For example, the first gap P1 is in the range of 30 to 100 μm, the second gap P2 is in the range of 30 to 120 μm, and the first gap P1. Is set to a value smaller than the second gap P2.

  Also, in FIG. 10, the second gap P2 is arranged on the atmosphere opening side (on the one side in the axial direction, the right side in the drawing) with respect to the first gap P1, and the cross-sectional wedge has a gap width increased toward the atmosphere opening side. Shaped. Thus, by increasing the gap width of the opening (right end) of the second gap P2, the injection of the second adhesive Q2 into the second gap P2 is facilitated. In FIG. 10, a second gap P2 having a wedge-shaped cross section is formed between the tapered surface 21a20 provided on the outer peripheral surface 21a2 of the first outer member 21 and the cylindrical inner peripheral surface 22a1 of the second outer member 22. However, it is not limited to this. For example, a tapered surface is provided on the inner peripheral surface 22a1 of the second outer member 22, and a second gap P2 having a wedge-shaped cross section is formed between the tapered surface and the cylindrical outer peripheral surface 21a2 of the first outer member 21. (Not shown). Alternatively, both the outer peripheral surface 21a2 of the first outer member 21 and the inner peripheral surface 22a1 of the second outer member 22 may be provided with tapered surfaces, and a second gap P2 having a wedge-shaped cross section may be formed therebetween. (Not shown).

  Moreover, in said embodiment, although the case where a hardening accelerator was provided to the 1st adhesive agent Q1 was shown, when this is unnecessary, you may abbreviate | omit provision of a hardening accelerator. Moreover, when using an ultraviolet curable adhesive as the 1st adhesive Q1, it can irradiate with an ultraviolet-ray and can accelerate | stimulate hardening of the 1st adhesive Q1.

  In the above embodiment, the bearing portion 10a and the fixed portion 10b of the inner member 10 are integrally formed. However, the present invention is not limited thereto, and for example, as shown in FIG. 11, the bearing portion 10a and the fixed portion 10b. And may be formed separately. The inner peripheral surface of the bearing portion 10a and the outer peripheral surface of the fixed portion 10b are fixed by an appropriate method such as press-fitting, gap adhesion, press-fitting adhesion (press-fitting with an adhesive interposed). Thereby, since the shape of the bearing part 10a and the fixed part 10b can be simplified, these processes are facilitated. Moreover, the bearing part 10a and the fixing | fixed part 10b can be formed with a different material. For example, since the bearing portion 10a can slide with the outer member 20, it is formed of copper iron-based sintered metal with an emphasis on wear resistance, while the fixed portion 10b does not slide with the outer member 20. The steel can be formed of iron-based sintered metal or melted material with emphasis on strength. Note that the bearing portion 10a and the fixed portion 10b do not necessarily have to be formed of different materials, and may be formed of the same material separately.

  In addition, when the dynamic pressure grooves 11a and 12a are for one-way rotation as shown in FIG. 3, the first outer member 21 and the second outer member 22 have different hue surfaces in order to identify the rotation direction. By doing so, it is possible to prevent erroneous assembly. In order to form surfaces having different hues, for example, materials having different hues may be used or surface treatment may be performed.

  In the above embodiment, the outer peripheral surface of the outer member 20, that is, the outer peripheral surface 22 a 2 of the cylindrical portion 22 a of the second outer member 22 is fitted to the inner peripheral surface of the housing 5 and can slide in the axial direction. However, the present invention is not limited to this, and the outer peripheral surface of the outer member 20 may be fixed to the inner peripheral surface of the stationary member by appropriate means such as press fitting or adhesion.

  Moreover, although the case where the dynamic pressure grooves 11a and 12a were formed in the inner member 10 was shown in the above embodiment, the present invention is not limited to this, and the dynamic pressure grooves may be formed in the outer member 20. In particular, if the dynamic pressure grooves are formed on the inner end surfaces 21 b 1 and 22 b 1 of the outer member 20, the dynamic pressure grooves can be formed simultaneously with the pressing of the first outer member 21 and the second outer member 22. Further, it is not always necessary to form the dynamic pressure grooves, and one or both of the dynamic pressure grooves of the radial bearing surface and the thrust bearing surface may be omitted.

  In the above embodiment, the case where both the dynamic pressure grooves 11a and 12a have the herringbone shape is shown, but the present invention is not limited to this, and other shapes such as a spiral shape and a step shape may be used. In particular, the dynamic pressure groove 12a formed on the thrust bearing surface is preferably a pump-out type that pushes lubricating oil to the outer diameter side (not shown). Thereby, since lubricating oil is positively supplied to the radial bearing gap R, generation of negative pressure can be prevented.

DESCRIPTION OF SYMBOLS 1 Bearing unit 2 Rotating shaft 3 Motor rotor 4 Fluid dynamic pressure bearing apparatus 5 Housing 6 Fan 7 Spring 10 Inner member 20 Outer member 21 First outer member 21a Cylindrical part 21b Flat plate part 22 Second outer member 22a Cylindrical part 22b Flat plate portion 30 Jig 31 Fixing jig 32 Moving jig 40 Nozzle P Radial gap P1 First gap P2 Second gap Q1 First adhesive Q2 Second adhesive R Radial bearing gap T Thrust bearing gap S Seal space

Claims (8)

A first outer member having an annular inner member, a cylindrical portion that is radially opposed to the outer peripheral surface of the inner member, and a flat plate portion that is axially opposed to one axial end surface of the inner member. A cylindrical portion fixed to the outer peripheral surface of the cylindrical portion of the first outer member, and a second outer member having a flat plate portion facing the other end surface in the axial direction of the inner member in the axial direction; A radial bearing gap formed between an inner circumferential surface of the cylindrical portion of the first outer member and an outer circumferential surface of the inner member; one axial end surface of the inner member; and the first outer member. A thrust bearing gap formed between the flat plate portion of the inner member and the other end surface in the axial direction of the inner member and the flat plate portion of the second outer member, and the radial bearing gap and the thrust bearing. A fluid dynamic bearing device comprising a lubricating oil interposed in a gap,
The outer peripheral surface of the cylindrical portion of the first outer member and the inner peripheral surface of the cylindrical portion of the second outer member are fitted through a radial gap without press-fitting, and the radial gap is A first adhesive that temporarily fixes the first outer member and the second outer member, and a second adhesive that completely seals the radial gap ,
A taper surface having a diameter expanded toward the atmosphere opening side is provided on the atmosphere opening side end portion of the inner peripheral surface of the cylindrical portion of the second outer member,
Among the radial gaps, a first gap and a second gap having a gap width larger than the first gap are provided in a region closer to the side closer to the tapered surface,
A fluid dynamic bearing device in which the first adhesive is disposed in the first gap and the second adhesive is disposed in the second gap .   The fluid dynamic bearing device according to claim 1, wherein the first adhesive is a cyanoacrylate-based instantaneous adhesive or an anaerobic adhesive.   The fluid dynamic bearing device according to claim 1, wherein the second adhesive is an epoxy adhesive or an ultraviolet curable adhesive.   The fluid dynamic bearing device according to claim 1, wherein the radial gap is in a range of 30 to 100 μm.   The fluid dynamic bearing device according to claim 1, wherein the second adhesive is disposed closer to the atmosphere opening side of the radial gap than the first adhesive. A first outer member having an annular inner member, a cylindrical portion that is radially opposed to the outer peripheral surface of the inner member, and a flat plate portion that is axially opposed to one axial end surface of the inner member. A cylindrical portion fixed to the outer peripheral surface of the cylindrical portion of the first outer member, and a second outer member having a flat plate portion facing the other end surface in the axial direction of the inner member in the axial direction; A radial bearing gap formed between an inner circumferential surface of the cylindrical portion of the first outer member and an outer circumferential surface of the inner member; one axial end surface of the inner member; and the first outer member. And a thrust bearing gap formed between the other end surface in the axial direction of the inner member and the flat plate portion of the second outer member, and the second outer member. the atmosphere opening side end portion of the inner peripheral surface of the cylindrical portion of the fluid dynamic bearing device having a tapered surface which is expanded toward the atmosphere opening side A method of assembly,
The inner member is arranged between the first outer member and the second outer member in the axial direction, and the outer peripheral surface of the cylindrical portion of the first outer member and the cylindrical portion of the second outer member are arranged. The inner circumferential surface of the first gap is fitted through a radial gap without press-fitting, and a first gap and a gap larger than the first gap in a region closer to the closing side than the tapered surface in the radial gap. a step of Ru formed a second gap width is large,
With the gap widths of the first thrust bearing gap and the second thrust bearing gap set, a first adhesive is interposed in the first gap of the radial gap, and the first outer member and the second thrust gap are set. a step of temporarily fixing the outer member in said first adhesive,
An assembly method of a fluid dynamic bearing device, wherein the second gap of the radial gap is completely sealed with a second adhesive. The fluid dynamic bearing device assembly method according to claim 6 , wherein after the first adhesive is supplied to the radial gap, a curing accelerator is applied to the first adhesive. After temporarily fixing the first outer member and the second outer member with the first adhesive, the second adhesive is filled on the air opening side of the radial gap with respect to the first adhesive. A method of manufacturing a fluid dynamic bearing device according to claim 6 .

Images