JP2013161501A - Method for manufacturing rotary apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which allows an operating time required for temporarily curing an adhesive lying between a bearing unit and a base to be reduced and achieves sufficient bonding strength of the adhesive after curing.SOLUTION: A method for manufacturing a rotary apparatus includes: a formation step 218 of forming a bearing unit and a base; an adhesion step 200 of bonding the bearing unit to the base; a transfer step 214 of transferring an assembly of the bearing unit and the base, including an adhesive in a temporarily cured state; a reheating step 216 of heating the assembly; and a total assembly step 220 of assembling a rotary apparatus with the heated assembly. The adhesion step 200 includes the steps of: heating the base; applying a thermosetting adhesive to the inner peripheral surface of a through-hole in the heated base; inserting the bearing unit in the through-hole from one end adjacent to the applied thermosetting adhesive toward the other end; and temporarily curing the thermosetting adhesive lying between the bearing unit and the base.

Description

  The present invention relates to a method of manufacturing a rotating device including a hub on which a recording disk is to be placed, a bearing unit that rotatably supports the hub, and a base in which a through hole is formed along the rotation axis of the hub. About.

  Disk drive devices such as hard disk drives are becoming smaller and larger in capacity, and are mounted on various electronic devices. In particular, the mounting of disk drive devices in portable electronic devices such as notebook computers and portable music playback devices is advancing. Conventionally, for example, a disk drive device described in Patent Document 1 has been proposed.

  Patent Document 2 discloses a method for manufacturing such a disk drive device. In this manufacturing method, the bearing unit is bonded and fixed to the bearing hole of the base.

JP 2007-198555 A JP 2011-165257 A

  In factories that produce disk drives, many parts of the production line are usually flow operations. In the bonding operation between the bearing unit and the base, the adhesive is often cured after a certain time after the adhesive is applied. At this time, if it waits until the adhesive has a nominal adhesive strength, it takes too much time for the bonding operation, and it becomes difficult to incorporate the bonding operation into the flow operation. Therefore, the bearing unit and the base are first bonded with an initial strength that does not deviate from each other, the main assembly work is performed in that state, and then the adhesive is applied to the nominal adhesive strength by batch processing using a heating furnace or the like. It is conceivable to cure until it has. In order to shorten the time required for the bonding work for obtaining this initial strength, it is conceivable to use a curing accelerator (Primer). Thereby, the time required for the bonding work for obtaining the initial strength can be made close to the line tact, and such a bonding work can be easily incorporated into the flow work.

  However, if a primer is used, foreign matters are mixed into the adhesive, and the original adhesive strength may not be obtained.

  Such a problem can occur not only in the disk drive device but also in other types of rotating equipment.

  The present invention has been made in view of such a situation, and its purpose is related to an operation for setting a temporary curing state in which an adhesive interposed between a bearing unit and a base of a rotating device can be further cured by a predetermined heat treatment. An object of the present invention is to provide a rotating device manufacturing technique capable of obtaining sufficient adhesive strength for the adhesive after such heat treatment while reducing the time.

  One embodiment of the present invention relates to a method for manufacturing a rotating device. The manufacturing method includes a hub on which a recording disk is to be placed, a bearing unit that rotatably supports the hub, and a base in which a through hole is formed along the rotation axis of the hub. The step of forming the bearing unit and the base, the step of heating the base, the step of applying an adhesive that hardens faster as the temperature increases to the inner peripheral surface of the through hole of the heated base, The step of inserting the bearing unit from one end to the other end of the through hole closer to the adhesive and the adhesive interposed between the bearing unit and the base can be further cured by a predetermined heat treatment. In the step of temporarily setting the assembly including the step of setting the cured state, the bearing unit, the base, and the adhesive interposed between them and the temporarily cured state, the bearing unit and the base are Comprising the stage had he the step of moving to another stage, heating the assembly in another stage, and a step of assembling a rotary apparatus using a heating assembly.

  According to this aspect, the temperature of the adhesive when the adhesive is in a temporarily cured state can be made relatively high.

  Note that any combination of the above-described constituent elements, and those obtained by replacing the constituent elements and expressions of the present invention with each other among methods, apparatuses, systems, etc. are also effective as an aspect of the present invention.

  According to the present invention, such a heat treatment is performed while shortening the time required for an operation of setting the adhesive interposed between the bearing unit and the base of the rotating device to a temporarily cured state that can be further cured by a predetermined heat treatment. Adhesive strength sufficient for the adhesive after applying can be obtained.

FIGS. 1A and 1B are a top view and a side view showing a rotating device manufactured by the manufacturing method according to the embodiment. It is the sectional view on the AA line of Fig.1 (a). It is a typical manufacturing process figure which shows the manufacturing method which concerns on embodiment. It is a manufacturing process figure which shows typically each channel of an adhesion process. It is a schematic diagram which shows the jig | tool for bearing adhesion | attachment. It is a schematic diagram which shows a mode when a base contacts a heater block. It is a graph which shows an example of the temperature rise of the base in a base heating process. It is sectional drawing of the base with which the thermosetting type adhesive agent was apply | coated. It is a figure which shows distribution of adhesive strength when a bearing unit and a base are adhere | attached on various conditions.

  Hereinafter, the same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are appropriately omitted. In addition, the dimensions of the members in each drawing are appropriately enlarged or reduced for easy understanding. Also, in the drawings, some of the members that are not important for describing the embodiment are omitted.

  The rotating device manufactured by the manufacturing method according to the embodiment includes a hub on which the recording disk is to be placed, a bearing unit that rotatably supports the hub, and a through hole formed along the rotation axis of the hub. And a base. Such a rotating device includes a disk drive device for rotating a magnetic recording disk, in particular, a hard disk drive.

  In the manufacturing method according to the present embodiment, the bearing unit is inserted into the through-hole of the base, and bonded and fixed with an adhesive that cures faster as the temperature is higher, such as a thermosetting adhesive. At this time, in order to quickly bring the thermosetting adhesive into a temporarily-cured state, not the primer but the preheated base heat is used. Thereby, a thermosetting adhesive agent can be rapidly made into a temporary hardening state, avoiding the bad influence to the adhesive strength by a primer. As a result, the temporary curing step of the thermosetting adhesive can be incorporated into the flow operation of the factory production line, and sufficient adhesive strength can be ensured during the main curing of the thermosetting adhesive.

The “temporarily cured state” of the thermosetting adhesive is a state in which the thermosetting adhesive can be further cured by a predetermined heat treatment, and can prevent displacement and inclination due to the weight of the members to be bonded. The adhesive strength may be lower than the nominal adhesive strength of the adhesive, or may be in a state where an initial strength that does not hinder work is obtained.
The “main cured state” of the thermosetting adhesive is a state obtained as a result of applying heat treatment to the thermosetting adhesive in a temporarily cured state, and no further heat treatment is required. Also good.

(Rotating equipment)
FIGS. 1A and 1B are a top view and a side view showing a rotating device 1 manufactured by the manufacturing method according to the present embodiment. FIG. 1A is a top view of the rotating device 1. FIG. 1A shows a state in which the top cover 2 is removed in order to show the inner configuration of the rotating device 1. The rotating device 1 includes a base 4, a rotor 6, a magnetic recording disk 8, a data read / write unit 10, and a top cover 2. The rotating device 1 is a hard disk drive that rotates the magnetic recording disk 8.
Hereinafter, the side on which the rotor 6 is mounted with respect to the base 4 will be described as the upper side.

The magnetic recording disk 8 is a glass 2.5-inch magnetic recording disk having a diameter of 65 mm, and the diameter of the hole in the center is 20 mm and the thickness is 0.65 mm.
The magnetic recording disk 8 is placed on the rotor 6 and rotates as the rotor 6 rotates. The rotor 6 is rotatably attached to the base 4 via a bearing unit 12 (not shown in FIG. 1A).

  The base 4 is formed by molding an aluminum alloy by die casting. The base 4 has a bottom plate portion 4 a that forms the bottom portion of the rotating device 1, and an outer peripheral wall portion 4 b that is formed along the outer periphery of the bottom plate portion 4 a so as to surround the mounting area of the magnetic recording disk 8. Six screw holes 22 are provided in the upper surface 4c of the outer peripheral wall 4b.

  The data read / write unit 10 includes a recording / reproducing head 13, a swing arm 14, a voice coil motor 16, and a pivot assembly 18. The recording / reproducing head 13 is attached to the tip of the swing arm 14, records data on the magnetic recording disk 8, and reads data from the magnetic recording disk 8. The pivot assembly 18 supports the swing arm 14 so as to be swingable around the head rotation axis S with respect to the base 4. The voice coil motor 16 swings the swing arm 14 around the head rotation axis S, and moves the recording / reproducing head 13 to a desired position within a predetermined swing range 15 on the upper surface of the magnetic recording disk 8. The swing range 15 is an arcuate region where the recording / reproducing head 13 can be located. The voice coil motor 16 and the pivot assembly 18 are configured using a known technique for controlling the position of the head.

  FIG. 1B is a side view of the rotating device 1. The top cover 2 is fixed to the upper surface 4 c of the outer peripheral wall portion 4 b of the base 4 using six screws 20. The six screws 20 correspond to the six screw holes 22, respectively. In particular, the top cover 2 and the upper surface 4c of the outer peripheral wall 4b are fixed to each other so that no leakage occurs from the joint portion to the inside of the rotating device 1.

  FIG. 2 is a cross-sectional view taken along line AA in FIG. The rotating device 1 further includes a laminated core 40 and a coil 42. The laminated core 40 has an annular portion and twelve salient poles extending outward in the radial direction (that is, the direction orthogonal to the rotation axis R), and is fixed to the upper surface 4 d side of the base 4. The laminated core 40 is formed by laminating four thin electromagnetic steel plates and integrating them by caulking. An insulating coating such as electrodeposition coating or powder coating is applied to the surface of the laminated core 40. A coil 42 is wound around each salient pole. When a three-phase substantially sinusoidal drive current flows through the coil 42, a drive magnetic flux is generated along the salient poles. On the upper surface 4 d of the base 4, an annular annular wall 4 e centering on the rotation axis R of the rotor 6 is provided. The laminated core 40 is press-fitted into the outer peripheral surface 4g of the annular wall portion 4e or bonded and fixed by a clearance fit.

  A through hole 4 h is formed in the base 4 along the rotation axis R of the rotor 6. On the inner peripheral surface of the through hole 4h, an annular first recess 4k and second recess 4m with the rotation axis R as the center are formed apart from each other in the axial direction (direction parallel to the rotation axis R). The first recess 4k is formed on the upper end side of the through hole 4h, and the second recess 4m is formed on the lower end side of the through hole 4h. The bearing unit 12 is inserted into the through hole 4h and fixed there. The adhesive used in this bonding is a thermosetting adhesive.

The bearing unit 12 includes a housing 44 and a sleeve 46 and rotatably supports the rotor 6 with respect to the base 4. The housing 44 has a bottomed cup shape in which a cylindrical portion and a bottom portion are integrally formed. That is, the housing 44 has a recess 44a that opens upward with the rotation axis R as the center. The housing 44 is fixed to the through-hole 4h of the base 4 by bonding with the bottom part facing down.
An ultraviolet curable conductive resin 52 is applied to the lower edge of the through hole 4 h from the base 4 to the housing 44.

  The sleeve 46 is a cylindrical member that is inserted into the concave portion 44 a of the housing 44 and fixed by adhesion. At the upper end of the sleeve 46, an overhanging portion 46a is formed projecting outward in the radial direction. This overhanging portion 46 a limits the movement of the rotor 6 in the axial direction in cooperation with the flange 30.

The shaft 26 is accommodated in the sleeve 46. A lubricant 48 is injected into a space between the shaft 26 and the hub 28 and the flange 30 which are a part of the rotor 6 and the bearing unit 12 which is a part of the stator.
On the inner peripheral surface of the sleeve 46, a pair of herringbone-shaped radial dynamic pressure grooves 50 spaced apart in the vertical direction are formed. A herringbone-shaped first thrust dynamic pressure groove (not shown) is formed on the lower surface of the flange 30 facing the upper surface of the housing 44. A herringbone-shaped second thrust dynamic pressure groove (not shown) is formed on the upper surface of the flange 30 facing the lower surface of the overhanging portion 46a. When the rotor 6 rotates, the rotor 6 is supported in the radial direction and the axial direction by the dynamic pressure generated in the lubricant 48 by these dynamic pressure grooves.

  A pair of herringbone-shaped radial dynamic pressure grooves may be formed in the shaft 26. Further, the first thrust dynamic pressure groove may be formed on the upper surface of the housing 44, and the second thrust dynamic pressure groove may be formed on the lower surface of the overhanging portion 46a.

  The rotor 6 includes a shaft 26, a hub 28, a flange 30, and a cylindrical magnet 32. The magnetic recording disk 8 is mounted on the disk mounting surface 28 a of the hub 28. Three disk fixing screw holes 34 are provided around the rotation axis R of the rotor 6 at intervals of 120 degrees on the upper surface 28 b of the hub 28. The clamper 36 is pressure-bonded to the upper surface 28b of the hub 28 by three disk-fixing screws 38 screwed into the three disk-fixing screw holes 34, and the magnetic recording disk 8 is pressure-bonded to the disk mounting surface 28a of the hub 28. Let

  The hub 28 is made of a steel material such as SUS430F having soft magnetism. The hub 28 is formed by, for example, pressing or cutting a steel plate, and is formed in a substantially cup-shaped predetermined shape. As the steel material of the hub 28, for example, stainless steel having a trade name of DHS1 supplied by Daido Steel Co., Ltd. is preferable because it has less outgas and is easy to process. Similarly, stainless steel of the product name DHS2 supplied by the company is more preferable in terms of further excellent corrosion resistance.

The shaft 26 is fixed to a hole 28c provided in the center of the hub 28 and provided coaxially with the rotation axis R of the rotor 6 in a state where press-fitting and adhesion are used in combination. The shaft 26 is formed of a steel material such as SUS420J2 that is harder than the raw material of the hub 28.
The flange 30 has an annular shape, and the flange 30 has an inverted L-shaped cross section. The flange 30 is fixed to the inner peripheral surface 28e of the hanging part 28d of the hub 28 by adhesion.

  The cylindrical magnet 32 is bonded and fixed to a cylindrical inner peripheral surface 28 f corresponding to the cylindrical surface inside the substantially cup-shaped hub 28. The cylindrical magnet 32 is formed of a rare earth material such as neodymium, iron, or boron, and faces the 12 salient poles of the laminated core 40 in the radial direction. The cylindrical magnet 32 is magnetized for driving with 16 poles in the circumferential direction (tangential direction of a circle with the rotation axis R as the center and perpendicular to the rotation axis R). The surface of the cylindrical magnet 32 is rust-proofed by electrodeposition coating or spray coating.

  There is a demand for a rotating device 1 as shown in FIG. 1 and FIG. 2 to increase the storage capacity while making it smaller. One technique for meeting this requirement is to increase the recording density of the magnetic recording disk 8. However, generally, when the recording density is increased, the influence of variations in the assembly accuracy and processing accuracy of the rotating device 1 tends to appear more strongly. For example, the error rate at the time of data reading / writing may deteriorate and the yield may decrease. There is.

  Among the assembling accuracy of the rotating device 1, the inclination of the magnetic recording disk 8 with respect to the recording / reproducing head 13 has a relatively large influence on the error rate. In particular, the magnetic field around an axis (axis G2 in FIG. 1) that is substantially orthogonal to the desired direction (direction G1 in FIG. 1) from the rotation axis R of the rotor 6 within a plane parallel to the upper surface 4d of the base 4 is shown. When the recording disk 8 rotates (tilts), the distance between the recording / reproducing head 13 and the upper surface of the magnetic recording disk 8 changes relatively large within the swing range 15. As a result, the error rate may be deteriorated.

Therefore, it is possible to suppress the tilt of the magnetic recording disk 8 around the axis G2 and more generally the axis that intersects the direction G1 in a plane parallel to the upper surface 4d of the base 4 (hereinafter referred to as the intersecting axis). It is desired.
From the viewpoint of variation in the distance between the recording / reproducing head 13 and the upper surface of the magnetic recording disk 8, the influence of the inclination of the magnetic recording disk 8 about the axis substantially along the direction G1 is relatively small. Further, if the magnetic recording disk 8 is not tilted from any direction, the work for attaching the bearing unit 12 to the base 4 needs to be performed more carefully and may take longer. There is sex. Further, since the processing accuracy required for the hub 28 is increased, the defect rate of the hub 28 may increase. For this reason, by placing emphasis on the inclination of the magnetic recording disk 8 around the cross axis and suppressing it to a smaller value, it is possible to ensure the desired effect of suppressing the inclination while suppressing an increase in the working time.

  The degree of inclination of the magnetic recording disk 8 is the maximum value and the minimum value of the height of the disk mounting surface 28a in the cross section of the rotating device 1 by a plane having a normal line parallel to the axis G2 and including the rotation axis R. Can be defined as the difference between The height of the disk mounting surface 28a may be determined based on a reference surface provided on the base 4, that is, the upper surface 4d. As an example, it is required to suppress this difference to 20 μm or less.

  In general, in the rotating device 1, the bonding gap between the bearing unit 12 and the base 4, that is, the gap between the inner peripheral surface of the through hole 4 h and the outer peripheral surface of the housing 44 does not become too small in consideration of ease of assembly and bonding work. Designed. The inventor has recognized that this relatively large gap is one of the causes of the inclination of the magnetic recording disk 8 around the cross axis. That is, since the bearing unit 12 can move relatively easily in the through hole 4h, there is a high possibility that the bearing unit 12 is bonded to the base 4 in an inclined state.

  On the other hand, for example, a method of suppressing the degree of freedom of the attitude of the bearing unit 12 by narrowing the bonding gap between the bearing unit 12 and the base 4 is conceivable. There is a possibility that the amount decreases and the adhesive strength decreases. Alternatively, when the bearing unit 12 is inserted into the through hole 4h, the contact surface is gnawed, the insertion operation cannot be performed smoothly, and the operation time may be long.

  Therefore, the present inventor has come up with the idea of promoting temporary curing by preheating the base 4.

(Production method)
The case where the above-described rotating device 1 is manufactured by the manufacturing method according to the present embodiment will be described.
FIG. 3 is a schematic manufacturing process diagram showing the manufacturing method according to the present embodiment. The manufacturing method according to the present embodiment is as follows:
A forming step 218 for forming a member of the rotating device 1 including the bearing unit 12 and the base 4;
A rotor side assembly step 219 for attaching the hub 28 to the bearing unit 12 and injecting the lubricant 48 into the bearing unit 12;
A base side assembly step 221 for attaching the laminated core 40 provided with the coil 42 to the base 4;
A cleaning step 215 for removing foreign matter adhering to the disk mounting surface 28a of the hub 28 by dripping IPA (Isopropyl Alcohol, isopropyl alcohol);
A bonding process 200 for bonding and fixing the bearing unit 12 to the base 4;
The assembly including the bearing unit 12 and the base 4 and the thermosetting adhesive interposed between them and being in a temporarily cured state is taken out from the stage where the bearing unit 12 and the base 4 are placed in the bonding process 200, and is electrically conductive. A conductive resin application step 211 for applying the conductive resin 52;
A UV irradiation step 213 for irradiating and curing the applied conductive resin 52 with UV (Ultraviolet);
A moving step 214 for moving the assembly after the conductive resin 52 is cured to a stage different from the stage where the bearing unit 12 and the base 4 are placed in the bonding step 200;
A reheating step 216 that heats the assembly in another stage to bring the thermosetting adhesive into a fully cured state;
An overall assembly step 220 of assembling the rotating device 1 using the assembly and other members that have undergone the reheating step 216;
An inspection process 222 for inspecting the appearance, operation, function, etc. of the assembled rotating device 1;
Is provided.
Note that another processing step may exist between the bonding step 200 and the conductive resin coating step 211 or between the moving step 214 and the reheating step 216.

  The forming step 218 may be configured using a known processing technique such as cutting or casting. The cleaning step 215 may be configured using a hub cleaning technique described with reference to FIG. 5 of Japanese Patent Application Laid-Open No. 2011-165286, for example. The rotor side assembly process 219, the base side assembly process 221 and the overall assembly process 220 may be configured using a known assembly technique. The inspection process 222 may be configured using known inspection techniques.

  The bearing unit 12 and the base 4 that have undergone the formation process 218, the rotor-side assembly process 219, and the base-side assembly process 221 are put into the head of the main production line. The cleaning process 215, the adhesion process 200, the conductive resin application process 211, the UV irradiation process 213, and the movement process 214 are performed in part of the main production line, that is, inline, and the reheating process 216 is performed in a batch process.

In the moving step 214, the assembly after the conductive resin 52 is cured through the UV irradiation step 213 is transferred to a jig different from the bearing bonding jig 300 described later.
In the reheating step 216, a predetermined number of assemblies are collected and put together in a heating furnace. In the heating furnace, heating is performed under the heating conditions necessary to change the thermosetting adhesive from the temporarily cured state to the fully cured state. The heating condition is, for example, heating at 95 degrees for 2 hours.

  The bonding process 200 includes eight channels 200a-200h in parallel. The working time in each of the eight channels 200a to 200h is equal to or longer than the line tact, but the time obtained by dividing the working time by the number of channels is within the line tact. As an example, the working time (hereinafter referred to as set time) in each of the eight channels 200a to 200h is 45 seconds, and the set time (45 seconds) is divided by the number of channels (8) (5.6 seconds). ) Is within the line tact (7 seconds). Alternatively, the number of channels in the bonding process 200 is set to a natural number larger than the number obtained by dividing the set time by the line tact.

  FIG. 4 is a manufacturing process diagram schematically showing each channel of the bonding process 200. Each channel of the bonding process 200 includes a base heating process 206, a heating release process 204, an adhesive application process 208, an insertion process 210, and a temporary curing process 212. Each process is continuously performed by a flow operation using the bearing bonding jig 300. Further, the base heating process 206 is performed continuously with the cleaning process 215 and the flow operation.

  In the base heating step 206, the base 4 is heated using the bearing bonding jig 300. By this heating, the temperature of the base 4 rises above the glass transition temperature of the thermosetting adhesive applied in the adhesive application process 208.

  FIG. 5 is a schematic diagram showing a bearing bonding jig 300. The bearing bonding jig 300 includes a head 302, a head guide portion 304, a head drive portion 306, a base holding portion 308, a slide portion 310, a slide portion 312, a slide pin 313, and a heater block 314. And a heater 316.

  When the base 4 is heated using the bearing bonding jig 300, first, the base 4 to be heated is attached to the base holding portion 308. Energization of the heater 316 is started, and the temperature of the heater block 314 is raised to a predetermined heating temperature. The sliding part 312 slides downward along the sliding pin 313 by the action of a slide driving part (not shown). As a result, the base 4, the base holding portion 308, the slide portion 310, and the slide portion 312 move together downward. The lower surface 4n of the base 4 is in contact with the upper surface 314a of the heater block 314.

  FIG. 6 is a schematic diagram showing a state when the base 4 is in contact with the heater block 314. In the base heating step 206, the base 4 is heated by bringing the base 4 into contact with the heater block 314 that has been heated by the heater 316 and has a high temperature in advance. The heating temperature of the heater block 314 and the heating time of the base 4 are determined so that the temperature in the vicinity of the through-hole 4h of the base 4 is not lower than the glass transition temperature of the thermosetting adhesive and not higher than the heat resistant temperature by this heating.

  In the heating release step 204, the heating of the base 4 is released. More specifically, when the heating time elapses after the base 4 and the heater block 314 come into contact with each other, the slide unit 310 is moved upward by a slide drive unit (not shown), and the base 4 and the heater block 314 are separated. .

  FIG. 7 is a graph showing an example of the temperature rise of the base 4 in the base heating step 206. The vertical axis in FIG. 7 indicates the measured value of the temperature in the vicinity of the through hole 4h of the base 4, and the horizontal axis indicates the time since the start of heating. The temperature of the heater block 314 was maintained at 230 degrees by the heater 316 before and after the base 4 was brought into contact with the heater block 314. In this way, by bringing the base 4 and the preheated heater block 314 into contact with each other, the temperature of the base 4 can be raised relatively quickly, and the base 4 can be heated for a relatively long time after the heating of the base 4 is finished. It can be seen that the high temperature state of 4 can be maintained.

  FIG. 8 is a cross-sectional view of the base 4 to which the thermosetting adhesive 54 is applied. In the adhesive application step 208, the thermosetting adhesive 54 is applied to the inner peripheral surface of the through hole 4 h of the base 4 that has been heated through the base heating step 206 and then released in the heat release step 204. In the adhesive application step 208, the thermosetting adhesive 54 is applied in a strip shape from the adhesive discharge nozzle 318 of the bearing bonding jig 300 to the inner peripheral surface of the through hole 4h over the entire inner peripheral surface. . In particular, the thermosetting adhesive 54 is applied to a region including the first recess 4k and is not applied to the second recess 4m. The temperature of the base 4 when the thermosetting adhesive 54 is applied is lower than the glass transition temperature and higher than the ambient temperature.

  Returning to FIG. 4, in the insertion step 210, using the head 302, the head guide unit 304, and the head driving unit 306, one end of the through hole 4 h closer to the applied thermosetting adhesive 54, that is, the through hole 4 h. The bearing unit 12 with the hub 28 is inserted from the upper end toward the lower end. In order to complete the insertion while the viscosity of the thermosetting adhesive 54 is relatively low, the bearing unit 12 is inserted within 10 seconds after the thermosetting adhesive 54 is applied in the adhesive application step 208.

  In the temporary curing step 212, the thermosetting adhesive 54 interposed between the bearing unit 12 and the base 4 is brought into a temporary cured state. In the temporary curing step 212, the temperature of the thermosetting adhesive 54 is raised from the ambient temperature due to the residual heat of the base 4. Thereby, hardening acceleration of the thermosetting adhesive 54 is achieved. In order to ensure the coaxiality between the bearing unit 12 and the base 4 or to prevent a change in height in the axial direction, the bearing bonding jig 300 is used until the thermosetting adhesive 54 is temporarily cured. The bearing unit 12 and the base 4 are held in a desired posture. Particularly, the bearing adhering jig 300 holds the disc mounting surface 28a of the hub 28 with respect to the upper surface 4d of the base 4 while adjusting the parallelism, the axial height, or both at the same time.

  According to the manufacturing method according to the present embodiment, when the bearing unit 12 is bonded to the base 4, the base 4 is preheated, the thermosetting adhesive 54 is applied, and the bearing unit 12 is inserted. Therefore, even if a curing accelerator is not used, the thermosetting adhesive 54 can be brought into a temporarily cured state in a time equivalent to or shorter than when the curing accelerator is used. When the thermosetting adhesive 54 is temporarily cured in this way, for example, the possibility that the bearing unit 12 is inclined with respect to the base 4 in the subsequent moving step 214 is low, or the possibility that the axial height is changed is low. Therefore, the overall yield is improved and the ease of work in the moving process 214 is improved.

  FIG. 9 is a diagram showing a distribution of adhesive strength when the bearing unit 12 and the base 4 are bonded under various conditions. The left side of FIG. 9 shows the distribution of the adhesive strength of the thermosetting adhesive in the temporary curing state, and the right side shows the distribution of the adhesive strength of the thermosetting adhesive in the main curing state. The conditions for adhesion between the bearing unit 12 and the base 4 are as follows: (A) Primer used, set time 45 seconds, (B) Primer not used, Base preheating, set time 3 minutes, (C) Primer not used According to the following form, the base preheating and the set time of 45 seconds were adopted.

  When (A) and (C) are compared, it can be seen that (C) is superior in both the adhesive strength during temporary curing and the adhesive strength during main curing. Therefore, according to the condition (C), it is unlikely that the coaxiality of the bearing unit is impaired by the work after temporary curing, or the possibility that the height in the axial direction changes is low, and the rotating device has excellent impact resistance. Can be manufactured. It can also be seen that (C) has less variation in adhesive strength. (B) also gives the same result as (C), but in this case a relatively long set time of 3 minutes is required. Therefore, in-line bonding process is difficult under the condition (B).

  Further, in the manufacturing method according to the present embodiment, the set time of each channel in the bonding process 200 can be shortened as compared with the case where the base 4 is not preheated. Thereby, a practical number of channels can be provided in parallel, and the bonding process can be inlined. As a result, production efficiency is improved.

  In the manufacturing method according to the present embodiment, the base 4 is heated by bringing the base 4 into contact with the heater block 314. Therefore, the heating efficiency can be increased as compared with the case where the base 4 is heated in a non-contact manner.

  Assuming that the thermosetting adhesive 54 is applied to the bearing unit 12 with respect to the target to which the thermosetting adhesive 54 is applied, the bearing unit 12 may idle in accordance with the movement of the adhesive discharge nozzle 318 during application. On the other hand, in the manufacturing method according to the present embodiment, the thermosetting adhesive 54 is applied to the inner peripheral surface of the through hole 4h of the heated base 4. Since the base 4 is generally heavier than the bearing unit 12 and easily held by a jig, the movement of the base 4 during application of the thermosetting adhesive 54 is suppressed, and the application of the thermosetting adhesive 54 is easy. improves.

  Further, in the manufacturing method according to the present embodiment, the base 4 in a state where the thermosetting adhesive 54 is not applied is heated, then the heating is released, and the base 4 thus released from the heating is thermoset. A mold adhesive 54 is applied. In this case, since the thermosetting adhesive 54 has a relatively low viscosity immediately after application, the insertion step 210 can be performed. That is, the heating of the base 4 and the insertion of the bearing unit 12 can be performed separately in time. Thereby, the ease of each operation | work improves.

  In the manufacturing method according to the present embodiment, the base 4 is cooled by natural heat dissipation while waiting for the thermosetting adhesive 54 to be in a temporarily cured state in the temporary curing step 212. Therefore, the operator can handle the assembly immediately after the thermosetting adhesive 54 is in a temporarily cured state.

  Further, in the manufacturing method according to the present embodiment, from the preheating of the base 4 to the temporary curing of the thermosetting adhesive 54 is performed by the bearing bonding jig 300. Therefore, compared with the case where these processes are performed with separate jigs, temperature management becomes easier, and the production facility can be further downsized.

  Further, in the manufacturing method according to the present embodiment, since the through hole 4h of the base 4 is expanded by preheating the base 4, the operation of inserting the bearing unit 12 into the through hole 4h in the inserting step 210 becomes smoother.

  A lubricant 48 is used in the bearing unit 12 of the rotating device 1. Therefore, when the bearing unit 12 is heated to a temperature substantially exceeding the glass transition temperature of the thermosetting adhesive 54, the lubricant 48 used in the bearing unit 12 can be reduced by evaporation. That is, there is a demand for making the thermosetting adhesive 54 as high as possible in order to temporarily cure the thermosetting adhesive 54 in a shorter time, while there is also a demand for suppressing the temperature rise of the lubricant 48 due to this. is there. Therefore, in the manufacturing method according to the present embodiment, since the thermosetting adhesive 54 is applied and the bearing unit 12 is inserted after the base 4 side is heated to a high temperature, the thermosetting adhesive 54 is connected to the base 4 side from the base 4 side. While heat is transferred, relatively little heat reaches the lubricant 48 in the bearing unit 12. Therefore, the temperature rise of the lubricant 48 is suppressed as compared with the temperature rise of the thermosetting adhesive 54, and both temporary curing of the thermosetting adhesive 54 and evaporation suppression of the lubricant 48 can be achieved. .

  The method for manufacturing the rotating device according to the embodiment has been described above. This embodiment is an exemplification, and it is understood by those skilled in the art that various modifications can be made to the combination of each component, and such modifications are also within the scope of the present invention.

  In the embodiment, the case where the rotating device 1 that is a hard disk drive is manufactured has been described. However, the manufacturing target is not limited to the hard disk drive. For example, the technical idea of the embodiment can be applied to a manufacturing method of an arbitrary rotating device including a bearing unit and a base that are fixed to each other by adhesion.

  In the embodiment, the case where the bonding process 200 is performed using the bearing bonding jig 300 has been described. However, the present invention is not limited to this. For example, each process included in the bonding process 200 may be performed by an individual jig. Good.

  In the embodiment, the case where the base 4 is heated by bringing the base 4 into contact with the heater block 314 heated in advance by the heater 316 and having a high temperature in the base heating step 206 has been described, but the present invention is not limited thereto. . For example, in the base heating step, the base 4 may be heated by non-contact heating means such as a halogen heater or a far infrared heater. In this case, it is not necessary to relatively move the heating means and the base 4 for heating, and the working time is shortened. Further, the base 4 is hardly damaged.

  1 rotating device, 2 top cover, 4 base, 4h through hole, 6 rotor, 8 magnetic recording disk, 10 data read / write unit, 12 bearing unit, 26 shaft, 28 hub, 40 laminated core, 42 coil, 300 bearing adhesion Jig, R rotation axis.

Claims (8)

A manufacturing method of a rotating device comprising: a hub on which a recording disk is to be placed; a bearing unit that rotatably supports the hub; and a base in which a through hole is formed along the rotation axis of the hub,
Forming a bearing unit and a base;
Heating the base;
Applying an adhesive that cures faster as the temperature increases to the inner peripheral surface of the heated base through-hole;
Inserting the bearing unit from one end of the through hole closer to the applied adhesive toward the other end;
A step of setting the adhesive interposed between the bearing unit and the base to a temporarily cured state that can be further cured by a predetermined heat treatment;
The assembly including the bearing unit, the base, and the adhesive interposed between them and the temporarily cured state is moved to a stage different from the stage on which the bearing unit and the base are placed in the step of temporarily curing. Process,
Heating the assembly in a separate stage;
Assembling a rotating device using the heated assembly.   The manufacturing method according to claim 1, wherein the step of setting the temporarily cured state includes a step of holding the bearing unit and the base in a desired posture with a predetermined fixing jig.   The manufacturing method according to claim 1, wherein the step of heating the base, the step of applying, the step of inserting, and the step of setting the temporarily cured state are performed continuously in a flow operation.   4. The method according to claim 1, wherein in the step of heating the base, the temperature of the base rises above the glass transition temperature of the adhesive applied in the applying step. 5. .   The manufacturing method according to claim 1, wherein the step of heating the base includes a step of heating the base by bringing a heating member heated by a heater into contact with the base.   6. The step of inserting includes a step of inserting a bearing unit into a through-hole of a base within 10 seconds after the adhesive is applied in the applying step. Manufacturing method. Further including releasing the heating of the base,
The manufacturing method according to claim 1, wherein the applying step includes a step of applying an adhesive to the inner peripheral surface of the through hole of the base whose heating is released.   The manufacturing method according to claim 1, wherein the applying step includes a step of applying an adhesive to a region including an annular recess formed on an inner peripheral surface of a through hole of the base. Method.

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