JP2009028633A - Cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning method capable of effectively removing dust and pollutants stuck to a motor unit without affecting a bearing or the like even in a state where the unit is completed. <P>SOLUTION: A nozzle unit where a first nozzle for jetting dry ice and a second nozzle for sucking and recovering the dry ice are integrated is traversed relatively to the surface to be cleaned of an object to be cleaned, the dry ice is jetted from the first nozzle to the surface to be cleaned, and particulates peeled off from the surface of the object to be cleaned or the pollutants dissolved from the surface of the object to be cleaned are sucked and recovered together with the dry ice from the second nozzle. Thus, cleaning is surely executed without the secondary contamination of bearing oil, and since a large load is not given to the object to be cleaned, thereby preventing deformation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cleaning method for parts that require high cleanliness, and more particularly to a recording disk drive device, a spindle motor used therefor, and a cleaning method for the parts.

  In recent years, hard disk devices (hereinafter abbreviated as HDDs), optical disk devices, and the like have been required to significantly improve recording density, and as a result, the area per bit on the disk surface has been rapidly reduced. As a result, the distance between the recording disk and the head element for recording / reproducing the signal is allowed only a small value year by year in order to suppress the error rate of the reproduction signal, and the flying height of the head element is 10 nm. It is as follows.

  Here, if dust particles (submicron order) are caught between the head and the surface of the recording disk while the recording disk is rotating, the head element cannot float from the recording disk, and the head element and the head gimbal on which the head element is mounted There is a risk of crashing the assembly. In order to prevent the occurrence of such a crash, the cleanliness of the air in the recording disk drive device needs to be maintained at a high level.

  Also, when assembling HDD parts such as a spindle motor, the operator's sebum adheres to the motor, etc., and it is transferred to another part of the HDD during the recording disk mounting work, or may cause outgassing. May remain as a contamination to the recording disk or the head element, and the head may stick when the disk starts rotating.

  In order to keep the cleanness of the air at a high level, not only the HDD is sealed so as to prevent the inflow of dust by blocking the inside of the recording disk drive device from the outside air but also generating dust particles in the recording disk device. In addition, it is necessary to prevent adhesion / remaining of sebum on the surface of the HDD internal parts.

  Therefore, when assembling such a motor, each member is first cleaned with a cleaning solution to remove dust particles and oils (cutting oil, worker's sebum) adhering to the surface of the member, and then cleaned in a clean room, etc. It is necessary to assemble each member sequentially in a high-degree environment under strict control (dust generation from the assembly environment, worker's sebum, etc.).

  However, even if individual parts are cleaned, it is difficult to completely prevent various types of contamination during assembly, and in order to suppress dust in the motor completed state, cleaning in the unit state (motor completed state) has begun to be required. It was.

  Here, as a cleaning method in the unit, for example, as shown in Patent Document 1, ultrasonic cleaning is performed by applying a water-repellent member to the opening of the rotor hub and the base and immersing the entire motor unit in the cleaning liquid. There is.

  Further, as shown in Patent Document 2, liquefied carbon dioxide (mainly dry ice) is jetted onto the object to be cleaned together with the carrier gas and the cleaning liquid, and the energy when the liquefied carbon dioxide collides and the energy when the liquefied carbon dioxide sublimates. There is something to clean with.

In addition, as shown in Patent Document 3, using a supercritical fluid obtained by pressurizing and heating CO2 gas to 75.2 kg / cm 2 or 31.1 ° C. or higher, oil and fat adhering to the object to be cleaned, moisture, There are those that wash away organic solvents, granular materials remaining on the surface of the object to be cleaned, exfoliated materials, and the like.
JP 2006-314188 A JP 2003-211106 A Japanese Patent Laid-Open No. 10-24270

  However, even if a water-repellent film is formed in a minute gap as in the method described in Patent Document 1, ultrasonic cleaning is essential for cleaning in the unit state, and the water-repellent film can be easily destroyed. . If the water-repellent film is partially broken, cleaning liquid may enter the motor and the motor bearing oil may come off, or a serious defect such as a short circuit inside the motor may occur. Further, the peeled water-repellent film becomes dust and causes secondary contamination.

  In order to prevent the cleaning liquid from entering the gap between the rotor and the stator, an O-ring can be fitted into the gap between the rotor and the stator. It is necessary to prepare it every time, and the manufacturing cost is increased, and the defect rate can be increased due to defective maintenance of the jig. In addition, the contact between the O-ring and the motor parts, the sliding portion of the O-ring holding jig itself is unavoidable in principle, and there is a problem that the cause of dust generation increases.

  Also, as described in Patent Document 2, by causing dry ice to collide with a motor component such as a hub at high speed from the injection nozzle, an eccentric load is applied to the hub (moment load is applied), and as a result, the shaft / hub press-fit portion As a result, the press-fit accuracy is deteriorated (for example, axial surface runout axial repetitive run out; hereinafter abbreviated as ARRO), and the bearing is damaged to affect the motor performance. Also, the dry ice sprayed from the spray nozzle scatters together with the surface contaminants after cleaning the component surface, causing secondary contamination. Furthermore, before the dry ice is sprayed by the spray nozzle, the dry ice is charged in the supply pipe, the object to be cleaned is also charged, and the dust peeled off by the dry ice is adsorbed again. Had the problem of losing.

  In addition, as described in Patent Document 3, a method using a supercritical fluid that is an intermediate form of gas and liquid as a cleaning agent can be said to be a very effective means for high-level cleaning of a single part, but has a low viscosity and penetration. In the method of immersing in a supercritical fluid with good properties, even if a water repellent is applied, it penetrates through a slight gap. Here, since the supercritical fluid has a density close to that of a liquid, the solubility of nonpolar substances such as oil is large. Therefore, the supercritical fluid that has permeated from the slight gap to the oil retaining portion of the bearing has a problem that even the oil in the bearing portion is dissolved (oil loss).

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a cleaning method capable of cleaning without causing deterioration in accuracy of parts even after a motor is assembled.

  In order to solve the above-described conventional problems, a cleaning method according to the present invention provides a nozzle unit in which a first nozzle that ejects dry ice and a second nozzle that sucks and collects dry ice are integrated. A step of preparing a traverse device capable of moving the nozzle unit relative to the surface to be cleaned of the object to be cleaned, a step of setting the object to be cleaned at a predetermined position, and a step of covering the nozzle unit by the traverse device. While moving relative to the cleaning surface, the dry ice is ejected from the first nozzle to the surface to be cleaned, and the granular material is peeled from the surface of the object to be cleaned together with the dry ice from the second nozzle. Alternatively, the method includes a step of sucking and collecting the contaminants dissolved from the surface of the object to be cleaned, and a step of removing the cleaning object from a predetermined position.

  This makes it possible to clean the unit without causing bearing oil omission, and the load applied to the parts by the dry ice ejected from the nozzle can be canceled by the suction force, thus suppressing the possibility of component deformation. It becomes possible to do. Further, since the peeled granular material or dissolved contaminant can be sucked on the spot, there is no fear of secondary contamination.

  The cleaning method according to the present invention is such that dry ice is accelerated by the carrier gas and ejected from the first nozzle.

  As a result, the amount of high-pressure liquefied carbon dioxide used for producing dry ice can be reduced, the impact load on the dry ice components can be increased, and the cleaning ability can be further improved.

  In the cleaning method according to the present invention, the carrier gas is carbon dioxide gas or air.

  As a result, the carrier gas itself can be compressed air piped in the factory or carbon dioxide gas obtained by sublimating recovered dry ice. Can reduce the environmental load.

  Furthermore, the cleaning method according to the present invention is such that the object to be cleaned is heated at least at any point before and after cleaning.

  Accordingly, it is possible to prevent moisture in the air from condensing on the surface of the component during or after cleaning, and the water droplets becoming “stain” on the surface of the component.

  Further, in the cleaning method according to the present invention, the tip of the nozzle outlet of the first nozzle has a substantially annular shape, and the second nozzle is sucked so as to surround the tip of the nozzle outlet of the first nozzle in a substantially ring shape. The mouth is formed.

  Thereby, the dry ice ejected from the first nozzle and the granular material peeled off from the surface of the object to be cleaned or the contaminant dissolved from the surface of the object to be cleaned can be reliably recovered, and the secondary contamination can be further reduced. It can be surely prevented.

  Further, in the cleaning method according to the present invention, a heating means is provided at the tip of the second nozzle.

  Thereby, the condensation of the nozzle tip and the object to be cleaned can be prevented. Further, the clogging of the first nozzle can be prevented.

  In the cleaning method according to the present invention, the object to be cleaned is grounded at least during cleaning.

  Thereby, it is possible to prevent charging due to static electricity caused by internal friction generated when dry ice is conveyed at high speed in the first nozzle or in the pipe, and it is possible to prevent reattachment of particles such as once separated particles.

  Further, in the cleaning method according to the present invention, the object to be cleaned is neutralized by an ionizer after cleaning.

  As a result, static electricity generated during cleaning can be removed from the object to be cleaned, and small powder particles scattered in the clean room after cleaning can be prevented from being drawn to the surface of the object to be cleaned.

  In addition, the cleaning method according to the present invention provides a plurality of nozzle units for cleaning the surface of an object to be cleaned that has a substantially rotationally symmetric shape around the rotation center axis. It is moved relatively so as to be arranged substantially evenly with respect to the rotation center axis.

  Thereby, since it arrange | positions in the substantially equal position with respect to the center axis | shaft of to-be-cleaned objects, such as a hub of a motor, an offset load is no longer applied with respect to to-be-cleaned object. As a result, it is possible to prevent the perpendicularity of the hub with respect to the shaft from deteriorating and the A-RRO of the disk when the disk is attached to be deteriorated.

  Furthermore, the cleaning method according to the present invention is such that the suction force generated by the air flow sucked from the second nozzle is larger than the jet power that the dry ice sprayed from the first nozzle gives to the surface of the object to be cleaned. is there.

  As a result, it is possible to reliably recover the dry ice and carrier gas ejected from the first nozzle, and the granular material peeled off from the surface of the object to be cleaned or the contaminant dissolved from the surface of the object to be cleaned.

  Further, the cleaning method according to the present invention measures the force applied to the object to be cleaned by the nozzle unit, and the ejection state of the first nozzle or the second nozzle so that a load exceeding a predetermined amount is not applied to the object to be cleaned. At least one of the suction states is controlled.

  Thereby, it is possible to suppress an excessive force from being applied to the object to be cleaned, and to minimize the deformation of the object to be cleaned.

  Furthermore, the cleaning method according to the present invention is such that the tip of the first nozzle is farther from the surface to be cleaned of the object to be cleaned than the tip of the suction port of the second nozzle.

  Thereby, it becomes easy to reliably recover the dry ice, the carrier gas, the granular material, or the contaminants without being scattered.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to apply the dry ice washing | cleaning which can remove oils and fats reliably as washing | cleaning methods to washing | cleaning of a completed motor. That is, oils and fats, powder particles on the product surface, and the like can be reliably removed and recovered without causing adverse effects such as deformation caused by spraying dry ice on the object to be cleaned.

  Moreover, since the motor can be effectively cleaned in a unit state by traversing the object to be cleaned with the injection nozzle and the suction nozzle as an integrated structure, the cleanliness of the motor can be dramatically improved.

  In addition, since the motor surface can be cleaned in the unit state after the motor is assembled, it is less necessary to clean the parts that make up the outer surface of the motor in advance. Management can be greatly simplified.

  In addition, management of dust adhering during motor assembly (cleaning of parts themselves and clean environment during assembly) can be simplified, so that significant cost reduction (equipment and quality control) is possible.

Embodiments of the cleaning method of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a spindle motor to which the cleaning method according to Embodiment 1 of the present invention is applied. This spindle motor is used for driving a recording disk and constitutes a part of a recording disk device such as an HDD.
<Configuration of spindle motor>
The spindle motor includes a base 100 constituting a stator (stationary member) 2, a rotor hub 101 made of aluminum or an iron alloy material constituting the rotor 1, and a rotor 1 for rotatably supporting the rotor 1 with respect to the stator 2. A hydrodynamic bearing device is provided.

  The hydrodynamic bearing device includes a hollow cylindrical sleeve 102, a shaft 106, and a disk-shaped thrust plate 105 that closes a lower portion of the sleeve 102. The sleeve 102 is formed of a metal material such as iron, iron alloy, copper, or copper alloy, and is fixed to the base 100.

  A disc-shaped thrust plate 105 is fixed to the sleeve 102 by a method such as adhesion, caulking, press-fitting, or welding. The opposite side (upper side in the figure) of the sleeve 102 to which the thrust plate 105 is fixed is open, the open end of the sleeve 102 is inclined toward the inside of the hydrodynamic bearing device, and the gap with the shaft 106 is open. Since it is arranged so as to become narrower from the end toward the hydrodynamic bearing device, it functions as the taper seal portion 108 and stably holds the lubricating oil 107 as a lubricant in the gap between the shaft 106 and the sleeve 102. ing. Further, on the inner peripheral surface side of the sleeve 106, a radial dynamic pressure generating groove (not shown) having a herringbone shape is formed side by side in the axial direction. The radial dynamic pressure generating groove may have a spiral shape. The surface of the sleeve 106 may be subjected to a surface hardening process such as a nickel plating process.

  The shaft 106 is a member made of a metal material and having a cylindrical outer peripheral surface with a diameter of 2 to 4 mm, and is inserted into the inner peripheral surface of the sleeve 106 in a rotatable state. Further, a disc-shaped thrust flange 109 is joined to the lower end of the shaft 106 by a method such as welding, press-fitting, adhesion, or screw tightening. Since the shaft 106 is used as an axis of rotation center, for example, a hard material such as SUS is used.

  The thrust flange 109 is a disk-shaped member, and is attached to the lower end side of the shaft 106 (the closed side of the hydrodynamic bearing device) as described above. The thrust flange 109 is disposed in a space surrounded by the step portion of the sleeve 102 and the thrust plate 105. The lower surface of the thrust flange 109 faces the thrust plate 105, and the upper surface of the thrust flange 109 faces the sleeve 102. A thrust dynamic pressure generating groove is formed on at least one surface of the facing surface.

  The thrust plate 105 is a member on a disc attached so as to cover the bottom surface of the hydrodynamic bearing device, and a thrust dynamic pressure generating groove (not shown) is formed on one side of the opposing surface of the opposing thrust flange 109. ing. The surface on which the thrust dynamic pressure generating groove is formed is not limited to the configuration of the present embodiment, and may be formed on any one of the opposing surfaces while forming a gap in the axial direction. That is, a thrust dynamic pressure generating groove may be formed on the lower surface of the thrust flange 109 or the upper surface of the thrust flange 109.

  Further, the shaft 106 including the radial dynamic pressure generating groove and the thrust dynamic pressure generating groove, the gap between the sleeve 102 and the inner peripheral cylindrical portion, and between the thrust flange 109 and the sleeve 102 and between the thrust flange 109 and the thrust plate 105. The gap is filled with lubricating oil 107.

  The rotor hub 101 which is the rotor 1 has a substantially bowl-like shape, a through hole is formed in the center portion, and the shaft 106 is fixed by adhesive press fitting, welding or the like. A substantially annular rotor magnet 104 is attached to the inner periphery of the rotor hub 101 and faces the stator core 103 in the radial direction. A disk mounting surface is formed on the upper surface of the rotor hub 101.

The rotor magnet 104 is attached in the circumferential direction on the inner peripheral surface side of the rotor hub 101. On the other hand, a sleeve 102 is fixed to the base 100 by bonding, adhesive press fitting, welding, or the like. A stator core 103 around which a coil 110 is wound is fixed substantially coaxially with the sleeve 102 by a method such as adhesion. A rotating magnetic field is generated by the rotor magnet 104 and the stator core 103 to apply a rotational force to the rotor hub 101.
<Configuration of cleaning device>
Next, FIG. 2A is a plan view showing a schematic configuration of a cleaning apparatus to which the cleaning method of the present embodiment is applied, and FIG. The stator 2 of the spindle motor is fixed to the cleaning mount 3 by a clamp 4. The cleaning mount 3 is grounded by a grounding means 14 to prevent the spindle motor from being charged. The grounding means is preferably connected to the rotor 1 when the object to be cleaned is the rotor 1, and is preferably connected to the stator 2 when the object to be cleaned is the stator 2.

  As shown in FIGS. 3 (a) and 3 (b), the cleaning apparatus includes a first nozzle 25 for spraying dry ice to clean the spindle motor, separated particles such as dust 7 (particles), The nozzle unit 24 is integrated with a second nozzle 26 that sucks and collects dissolved contaminants (contamination) and the like together with dry ice sublimated. The detailed configuration of the nozzle unit 24 will be described later. The first nozzle 25 is connected to the cleaning fluid supply pipe 5, and the second nozzle 26 is connected to the suction recovery pipe 6.

The nozzle unit 24 is fixed to the traverse units 11 and 12 and the rotary table 13 provided so as to be movable / rotatable in the horizontal direction, the vertical direction, and the rotation axis direction with respect to the spindle motor. Thereby, the nozzle unit 24 can be moved relative to the cleaning surface of the object to be cleaned.

  In addition, since the object to be cleaned has a substantially rotationally symmetric shape around the rotation center axis, a plurality of the nozzle units 24 are prepared for cleaning the surface of the object to be cleaned. The traverse units 11 and 12 and the rotary table 13 are relatively moved with respect to the rotation center axis.

The cleaning mount 3 is provided with a heating device (not shown) and is disposed on the cleaning device base 18 by the elastic support portion 15. The elastic support portion 15 is provided with a plurality of load sensors 16 for measuring a load applied to the spindle motor by injection. Then, the reaction force when the cleaning agent is injected / sucked is measured and fed back to the pressure control device 17 to control the injection force and the suction force.
<Configuration of nozzle unit>
As shown in FIG. 3 (b), the nozzle unit 24 injects liquefied carbon dioxide 20 for cleaning an object to be cleaned together with a carrier gas 22 (for example, compressed clean air or carbon dioxide gas) to dry ice. A first nozzle 25 for generating and ejecting pellets 27, a dry ice pellet 27 partially sublimated, and a second nozzle 26 for sucking and collecting the separated granular material such as dust 7 and dissolved contaminants. It is united.

  More specifically, a liquefied carbon dioxide supply pipe 21 for supplying liquefied carbon dioxide 20 and a carrier gas supply pipe 23 for supplying a carrier gas 22 around the first nozzle 25 are coaxial from the pressure control device 17. Are connected to each other. The cleaning fluid supply pipe 5 described above has a liquefied carbon dioxide supply pipe 21 and a carrier gas supply pipe 23 arranged coaxially.

  Here, the tip of the carrier gas supply pipe 23 protrudes from the tip of the liquefied carbon dioxide supply pipe 21. Further, a second nozzle 26 is disposed so as to surround the first nozzle 25. Here, the tip of the second nozzle 26 is configured to protrude further than the tip of the first nozzle. The liquefied carbon dioxide supply pipe 21 is composed of a metal or conductive flexible tube and is grounded.

  Here, the liquefied carbon dioxide 20 is supplied from a storage cylinder (not shown) having a pressure of several tens of atmospheres, the pressure and flow rate of which are controlled via the pressure controller 17. The carrier gas 22 is compressed clean air supplied into the factory, and is supplied with the pressure and flow rate controlled via the pressure controller 17. Note that the pressure of the liquefied carbon dioxide 20 and the carrier gas 22 is controlled by the pressure controller 17 to several atmospheric pressures (about 3 to 6 atmospheric pressures). Further, the second nozzle 26 is also connected to the pressure control device 17, and the suction pressure and the flow rate are controlled.

A heating device (not shown) is installed near the tip of the first nozzle 25 to warm the carrier gas and prevent the liquefied carbon dioxide 20 from being clogged in the supply pipe.
<Operation of device and cleaning action>
Next, operation | movement of this cleaning apparatus is demonstrated using the process flowchart shown in FIG. First, the object to be cleaned is fixed to the cleaning mount 3 using the clamp 4. At this time, the object to be cleaned is set to be grounded by the grounding means 14. Next, the object to be cleaned is preheated as necessary. This prevents condensation during cleaning. A plurality of objects to be cleaned may be set at the same time.

  Next, the plurality of nozzle units 24 are moved relative to the object to be cleaned (here, a spindle motor), and arranged so as to be substantially at the target positions around the rotation axis.

  Then, the cleaning fluid 9 is ejected and the sublimate is sucked and collected together with the contaminants. Then, if necessary, the object to be cleaned is taken out by removing electricity or heating with an ionizer or the like. When a plurality of objects to be cleaned are attached to the cleaning mounting base 3, the cleaning may be performed sequentially.

  The liquefied carbon dioxide 20 is sucked out from the liquefied carbon dioxide supply pipe 21 at a high speed by the negative pressure generated when the carrier gas 22 flows through the carrier gas supply pipe 23 at a high speed. At this time, the liquefied carbon dioxide 20 is cooled by the adiabatic expansion that occurs abruptly and becomes dry ice pellets 27.

  Then, the dry ice pellets 27 are accelerated as they are generated and become the cleaning fluid 9 mixed with the carrier gas 22, and move toward the dust 7 and contaminants adhering to the surface of the object 1 to be cleaned at high speed (several tens to several hundreds m / sec). Injected at. Dirt adhering to the surface of the object to be cleaned 30 due to the collision energy when the dry ice pellets 27 injected from the first nozzle 25 (injection nozzle) collide and the expansion pressure accompanying the sublimation of the dry ice pellets 27 Is removed or dissolved in liquefied carbon dioxide and removed (cleaned) from the object to be cleaned. The dirt removed from the cleaning object 30 is sucked and collected by the second nozzle 26 together with the dry ice partially sublimated. Accordingly, since the cleaning fluid 9 and the separated dust and contaminants do not scatter, there is no possibility of causing secondary contamination after cleaning. Furthermore, although the temperature of dry ice itself is low, since it instantly sublimes due to collision energy, there is no concern that the object to be cleaned will be excessively cooled to cause thermal shock. However, if the cleaning time becomes long, the temperature of the object to be cleaned is too low, and there is a possibility that moisture in the air will be absorbed and condensed after cleaning. In order to prevent this, the object to be cleaned may be heated in advance, or the object to be cleaned may be heated during or after cleaning.

  According to the present embodiment, since the nozzle unit 24 can move relative to the object to be cleaned 30, the surface of the object to be cleaned 30 can be thoroughly cleaned. Further, since the second nozzle (suction nozzle) 26 is provided integrally with the first nozzle (jet nozzle) 25, the contaminants peeled or dissolved by the sprayed dry ice pellets are The nozzle 26 immediately collects it by suction. Therefore, the peeled contaminants are not diffused into the surrounding environment by jetting, and secondary contamination can be prevented.

  Moreover, the 1st nozzle 25 and the 2nd nozzle 26 are integrated as above-mentioned, and are jetting and suctioning. As a result, the spraying force applied to the object to be cleaned can be relatively weakened by the suction force, so that it also has an effect of reducing the stress applied to the object to be cleaned when spraying dry ice. Further, the injection force and the suction force are measured by a load sensor 16 disposed on an elastic support 15 that elastically supports the cleaning mount 3 and fed back to the pressure control device 17 so that the load applied to the object to be cleaned is always constant. It becomes possible to control. With these configurations, it is possible to prevent deterioration of the assembly accuracy of the object to be cleaned (motor) and damage to the bearing due to the load during the injection of liquefied carbon dioxide, which the conventional example has.

  In addition, since the plurality of nozzle units 24 are arranged so as to be almost evenly balanced with respect to the rotation axis, the uneven load due to the injection force, the deterioration of press-fitting accuracy with respect to the shaft 106 of the rotor hub 101 due to the uneven load, and the bearing Can prevent damage.

  Further, in the conventional apparatus, when liquefied carbon dioxide is transported in the supply pipe, it is charged by generating static electricity due to mutual friction and friction with the pipe inner wall constituting the supply pipe line. In some cases, dust reattaches and a good cleaning effect cannot be obtained. However, in this embodiment, the object to be cleaned, the cleaning mounting base 3 to which the object to be cleaned is fixed, and the liquefied carbon dioxide supply pipe 21 are grounded, so that they are not charged and the separated dust is immediately recovered. Therefore, a good cleaning effect can be obtained. If the charge cannot be completely suppressed even after that, the ionization may be performed by an ionizer as soon as possible after cleaning. This minimizes particulate adsorption due to static electricity.

  In addition, the cleaning mounting base 3 of the cleaning device has a heating device and a heating device (not shown) for heating the carrier gas at the tip of the injection nozzle. As a result, the problem that the object to be cleaned is condensed after cleaning can be solved.

<Modification of First Embodiment>
Although the first embodiment of the present invention has been described above, the present invention is not limited to the first embodiment, and various modifications can be made without departing from the scope of the invention.

(A)
In the description of the first embodiment, the one applied to the apparatus for cleaning the object to be cleaned from the direction parallel to the rotation axis (vertical direction) is used, but as a modification, as shown in FIG. It is also possible to wash by spraying dry ice from a direction perpendicular to the axis (horizontal direction). Further, in order to have a combination of the description of the first embodiment and this modification, it is also possible to provide an electromagnetic rotation mechanism in the nozzle unit base so that the vertical direction and the horizontal direction can be arbitrarily selected. is there.

(B)
In the above description, the object to be cleaned is a motor unit (spindle motor) in which the bearing portion is also completed. However, as shown in FIG. 5, the rotor hub 101 can be cleaned in a single product state.

(C)
In the above description, the object to be cleaned is a motor unit (spindle motor) in which the bearing portion is also completed, but it is also possible to clean the base 2 in a single product state as shown in FIG. When it is not necessary to consider the unbalanced load on the object to be cleaned as in the case of the base 2, or when the object to be cleaned is not axisymmetric about the rotation center axis, a plurality of nozzle units 24 need to be arranged uniformly. However, it can also be implemented with a single nozzle unit 24.

  In the above description, the motor shown in FIG. 1 is taken as an example, but the applicable range of the present invention is not limited to this, and it is needless to say that the present invention can be applied to any other form of motor. .

  The cleaning method according to the present invention can reliably perform cleaning without deteriorating the shape accuracy and performance of the apparatus even when the apparatus is completed or semi-completed, and particularly requires high cleanliness. It is useful as a cleaning method for information-related devices such as HDDs, semiconductor-related elements, and video devices.

Cross section of spindle motor (A) The top view of the washing | cleaning apparatus to which the washing | cleaning method in Embodiment 1 of this invention is applied, (b) The cross-sectional view of the washing | cleaning apparatus to which the washing | cleaning method in Embodiment 1 of this invention is applied. (A) Schematic diagram showing the relationship between the nozzle unit of the cleaning apparatus to which the cleaning method in Embodiment 1 of the present invention is applied and the traverse apparatus, (b) of the cleaning apparatus to which the cleaning method in Embodiment 1 of the present invention is applied. Cross section of nozzle unit (A) The top view of the washing | cleaning apparatus which applied the washing | cleaning method in the modification (A) of Embodiment 1 of this invention, (b) The washing | cleaning method in the modification (A) of Embodiment 1 of this invention was applied. Cross section of cleaning device Cross-sectional view of a cleaning apparatus to which the cleaning method in the modification (B) of the first embodiment of the present invention is applied. Cross-sectional view of a cleaning apparatus to which the cleaning method in the modification (C) of the first embodiment of the present invention is applied Process flow diagram of cleaning method in embodiment 1 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 3 Cleaning mount 4 Clamp 5 Cleaning fluid supply pipe 6 Suction collection pipe 7 Dust 9 Cleaning fluid 10 Collected substance 11, 12 Traverse unit 13 Rotary table 14 Grounding means 15 Elastic support part 16 Load sensor 17 Pressure control apparatus 18 Cleaning device base 20 Liquefied carbon dioxide 21 Liquefied carbon dioxide supply pipe 22 Carrier gas 23 Carrier gas supply pipe 24 Nozzle unit 25 First nozzle 26 Second nozzle 27 Dry ice pellet 30 Object to be cleaned 100 Base 101 Rotor hub 102 Sleeve 103 Stator core 104 Rotor magnet 105 Thrust plate 106 Shaft 107 Lubricating oil 108 Tapered seal part 109 Thrust flange 110 Coil

Claims (13)

Preparing a nozzle unit in which a first nozzle for ejecting dry ice and a second nozzle for sucking and collecting the dry ice are integrated;
Preparing a traverse device capable of moving the nozzle unit relative to the surface to be cleaned;
Setting the object to be cleaned at a predetermined position;
While the nozzle unit is moved relative to the surface to be cleaned by the traverse device, the dry ice is ejected from the first nozzle to the surface to be cleaned, and from the second nozzle, Sucking and collecting the granular material peeled off from the surface of the object to be cleaned together with the dry ice or the contaminant dissolved from the surface of the object to be cleaned;
And a step of removing the cleaning object from a predetermined position.   The cleaning method according to claim 1, wherein the dry ice is accelerated by a carrier gas and ejected from the first nozzle.   The cleaning method according to claim 2, wherein the carrier gas is carbon dioxide gas or air.   The cleaning method according to any one of claims 1 to 3, wherein the object to be cleaned is heated at least at any time point before and after cleaning.   The tip of the nozzle outlet of the first nozzle has a substantially annular shape, and the suction nozzle is formed so that the second nozzle surrounds the periphery of the tip of the nozzle of the first nozzle in a substantially ring shape. The cleaning method according to any one of claims 1 to 4, wherein:   The cleaning method according to claim 1, wherein a heating means is provided at a tip portion of the second nozzle.   The cleaning method according to claim 1, wherein the object to be cleaned is grounded at least during cleaning.   The cleaning method according to claim 1, wherein the object to be cleaned is neutralized by an ionizer after cleaning.   In order to clean the surface of an object to be cleaned that has a substantially rotationally symmetric shape around the rotation center axis, a plurality of the nozzle units are prepared, and at least during the cleaning, the plurality of nozzle units are substantially set with respect to the rotation center axis. The cleaning method according to any one of claims 1 to 8, wherein the cleaning method is relatively moved so as to be evenly arranged.   2. The suction force generated by the air flow sucked from the second nozzle is larger than the jet power given to the surface of the object to be cleaned by the dry ice ejected from the first nozzle. The washing | cleaning method of any one of 1-9.   The force exerted by the nozzle unit on the object to be cleaned is measured, and the spraying state at the first nozzle or the suction state at the second nozzle is not applied to the object to be cleaned. The cleaning method according to claim 1, wherein at least one of them is controlled.   The cleaning method according to claim 5, wherein the tip of the first nozzle is farther from the surface to be cleaned of the object to be cleaned than the tip of the suction port of the second nozzle. The cleaning method according to claim 1, wherein the component is a component used in a recording disk drive device.