JP2019062710A - Measuring method and adjustment method - Google Patents

Abstract

To improve assembly accuracy by measuring dimensions between bearing members with high accuracy, and adjusting.SOLUTION: In a motor having a shaft placed along the medial axis 9, a hub 50 having a through hole 210 into which the shaft is inserted, and a one side ring 111 and the other side ring 112 fixed to the shaft on the farther one axial side than the hub and on the farther the other axial side than the hub, axial clearance dimensions between the hub and the one and the other side rings are measured. At first, the hub is fixed, and axial movement of the hub is limited. Next, the shaft is pushed to one side in the axial direction, and the other side ring is brought into contact with the hub. Subsequently, the shaft is pushed to the other side in the axial direction, and the one side ring is brought into contact with the hub. Travel of one side end of the shaft in the axial direction is measured. The other side end of an elastic member 63 having fixed one side end is brought into contact with the shaft directly or indirectly, thus giving an elastic force E to the shaft for directing toward the other side in the axial direction.SELECTED DRAWING: Figure 4

Description

  The present invention relates to measurement methods and adjustment methods.

Conventionally, a disk drive device for driving a hard disk or an optical disk is known. A motor for rotating the disk is mounted on the disk drive. The motor performs high speed rotation by having a dynamic pressure bearing between the rotating member and the non-rotating member. In order to improve the stability and accuracy of rotation of a disk or the like during high-speed rotation, there is a need for a technique for improving the accuracy of each member forming a bearing in a motor. About the manufacturing method of the conventional motor bearing, it describes in Unexamined-Japanese-Patent No. 2008-309189, for example.
JP, 2008-309189, A

  However, when measuring the dimensions of the members forming the bearing after assembly, if errors or variations occur in the measurement accuracy, errors may occur in the assembly accuracy of the bearing after the additional adjustment based on the evaluation result.

  An object of the present invention is to provide a technique capable of improving the assembly accuracy after adjustment based on the measurement result by measuring the dimensions between members forming the bearing with high accuracy.

  According to a first exemplary invention of the present application, a shaft disposed along a vertically extending central axis, a hub having a through hole into which the shaft is inserted, and a shaft fixed to the shaft on one axial side with respect to the hub Axial direction between the hub and the one side ring and the other side ring in a motor having one of the side rings and the other side ring fixed to the shaft on the other side in the axial direction with respect to the hub Measuring the gap dimension of the a), and a) fixing the hub to limit axial movement of the hub; b) pushing the shaft axially to one side, the other side Contacting the ring with the hub; c) pressing the shaft axially to the other side after the step b), contacting the one side ring with the hub; Measuring the axial movement of one end of the shaft from the end of step b) to the end of step c), at least step b), c), And in the step d), the elastic force E directed to the other side in the axial direction is applied to the shaft by bringing the other end of the elastic member, one end of which is fixed, into direct or indirect contact with the shaft. give.

  According to the first exemplary invention of the present application, the axial clearance dimension between the hub forming a part of the bearing and the one side ring and the other side ring can be measured with high accuracy. As a result, the assembly accuracy of the bearing after adjustment based on the measurement result can be improved.

FIG. 1 is a cross-sectional view of the disk drive device according to the first embodiment. FIG. 2 is a partially enlarged view of the spindle motor of FIG. FIG. 3 is a cross-sectional view schematically showing how the thrust clearance of the fluid bearing according to the first embodiment is measured. FIG. 4 is a cross-sectional view schematically showing how a thrust gap of the fluid bearing according to the first embodiment is measured. FIG. 5 is a flow chart showing the process of measuring and adjusting the thrust clearance of the fluid bearing according to the first embodiment. FIG. 6 is a diagram showing the result of analyzing the relationship between the magnitude of the elastic force E according to the first embodiment and the variation in the measurement result of the thrust gap. FIG. 7 is a diagram showing the result of analyzing the relationship between the difference between the magnitude of the force F and the magnitude of the elastic force E and the variation of the measurement result of the thrust gap according to the first embodiment. FIG. 8 is a cross-sectional view schematically showing how a thrust gap of a fluid bearing according to a modification is measured.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. In the following embodiments, a spindle motor will be described as an example of the “motor” including the “fluid bearing”. In addition, the direction parallel to the central axis of the motor is "axial direction", the direction perpendicular to the central axis of the motor is "radial direction", and the direction along an arc centered on the central axis of the motor is "circumferential direction". It is called. In the following embodiments, the axial direction is the vertical direction, and the shape and positional relationship of each part will be described with the cover unit side up with respect to the stator unit. However, the definition in the vertical direction is not intended to limit the use direction of the motor and the disk drive to be measured according to the present invention. Further, in the present application, the “parallel direction” also includes a substantially parallel direction. Furthermore, in the present application, the “orthogonal direction” also includes a substantially orthogonal direction.

<1. First embodiment>
<1-1. Disk drive configuration>
FIG. 1 is a cross-sectional view of a disk drive device 100 according to a first embodiment of the present application. The disk drive device 100 is a hard disk device that reads information from the magnetic disk 101 and writes information to the magnetic disk 101 while rotating three magnetic disks 101 having a circular hole at the center. As shown in FIG. 1, the disk drive device 100 has a spindle motor 1, three magnetic disks 101, an access portion 102, and a housing 103 for housing these.

  The spindle motor 1 rotates the magnetic disk 101 about the central axis 9 while supporting the magnetic disk 101. The structure of the spindle motor 1 will be described in detail later.

  The magnetic disk 101 is a medium on which information is recorded. In the present embodiment, three magnetic disks 101 are arranged. The three magnetic disks 101 are axially stacked via the spacers 105 and 106. The number of magnetic disks 101 may be two or less, or four or more.

  The access unit 102 has three sets of heads 107 and arms 108 and a head moving mechanism 109. The head 107 approaches the surface of the magnetic disk 101 and magnetically reads at least one of the information recorded on the magnetic disk 101 and the information written on the magnetic disk 101. The head 107 is supported by an arm 108. The arm 108 swings while being supported by the head moving mechanism 109.

  The housing 103 has a base portion 40 and a cover portion 104. The base portion 40 is also a part of the spindle motor 1, and a part of the base portion 40 radially spreads on the lower side of the magnetic disk 101. The base 40 is molded by casting, for example. The base 40 has an opening. The cover portion 104 is fitted in the opening of the base portion 40. Thus, the housing 103 is configured. The base portion 40 and the cover portion 104 are combined so that the airtightness in the housing 103 is not lost.

  The internal space of the housing 103 is preferably a clean space with extremely little dust or dirt. In the present embodiment, the inside of the housing 103 is filled with helium gas, which is a gas having a density lower than that of air. As a result, wind noise and the like when the magnetic disk 101 rotates is reduced. However, hydrogen gas, nitrogen gas, or air may be filled instead of helium gas. In addition, a mixed gas of helium gas, hydrogen gas, or nitrogen gas and air may be filled.

<1-2. Configuration of spindle motor>
Subsequently, the configuration of the spindle motor 1 will be described. FIG. 2 is a partially enlarged view of the spindle motor 1 of FIG. As shown in FIG. 2, the spindle motor 1 has a shaft 10, an annular member 11, a rotating portion 20, a stator unit 30, and a base portion 40. The spindle motor 1 according to the first embodiment of the present application is a three-phase motor.

  The shaft 10 is a substantially cylindrical member disposed along the central axis 9. The shaft 10 rotatably supports the rotating unit 20 around the central axis 9. The shaft 10 is formed of, for example, a metal such as stainless steel. The upper end portion of the shaft 10 is fixed to the cover portion 104 of the housing 103 (see FIG. 1). The lower end of the shaft 10 is fixed to the base 40. The shaft 10 may be a hollow shaft having a through hole that penetrates in the axial direction.

  An annular member 11 is provided on the outer peripheral surface of the shaft 10. The annular member 11 is a member fixed to the shaft 10 and protruding radially outward from the outer peripheral surface of the shaft 10. The annular member 11 is composed of an upper ring 111 and a lower ring 112. The upper ring 111 is at least partially fixed to the shaft 10 axially above the sleeve 21 described later. The lower ring 112 is at least partially fixed to the shaft 10 axially below the sleeve 21 described later.

  In the outer peripheral surface of the upper ring 111, the diameter of the outer peripheral surface 111A at the upper part from the approximate center in the axial direction decreases as it goes upward. In the outer peripheral surface of the upper ring 111, the diameter of the outer peripheral surface 111B at the lower part from the approximate center in the axial direction decreases in the downward direction. Further, in the outer peripheral surface of the lower ring 112, the diameter of the outer peripheral surface 112A at the lower part from the approximate center in the axial direction decreases as it goes downward. In the outer peripheral surface of the lower ring 112, the diameter of the outer peripheral surface 112B at the upper part from the approximate center in the axial direction decreases in the upward direction. The shaft 10 and the annular member 11 constitute a “stationary member” according to the present embodiment.

  The rotating portion 20 is a “rotating member” that rotates around the central axis 9 with respect to the shaft 10 and the annular member 11. The rotating portion 20 includes a sleeve 21, an outer hub 22, a clamp member 23, a rotor magnet 24, and a yoke 25. In the present embodiment, the sleeve 21 and the outer hub 22 are formed as separate members. However, the sleeve 21 and the outer hub 22 may be members in one connection.

  The sleeve 21 is a cylindrical member that annularly expands around the shaft 10. For the material of the sleeve 21 and the outer hub 22 described later, for example, a metal such as an aluminum alloy or a ferromagnetic stainless steel is used. A radially inner side of the sleeve 21 is provided with a through hole 210 penetrating the sleeve 21 in the axial direction. The shaft 10 is inserted into the through hole 210. Further, as described later, the sleeve 21 is rotatable with respect to the shaft 10 and the annular member 11 about the central axis 9. The sleeve 21 opposes the first inner circumferential surface 211A opposite to the outer circumferential surface 111B of the upper ring 111 with a slight gap, and the outer circumferential surface of the shaft 10 with a slight gap above the groove 21C described later. And a second inner circumferential surface 211B. Further, the sleeve 21 has a slight gap with the first inner circumferential surface 212A opposed to the outer circumferential surface 112B of the lower ring 112 with a slight gap, and with the outer circumferential surface of the shaft 10 below the groove 21C described later. And a second inner circumferential surface 212B facing each other.

  The first inner circumferential surface 211A of the sleeve 21 and the outer circumferential surface 111B of the upper ring 111, and the second inner circumferential surface 211B and the outer circumferential surface of the shaft 10 face each other via a slight gap filled with a fluid such as lubricating oil. Further, the first inner circumferential surface 212A of the sleeve 21 and the outer circumferential surface 112B of the lower ring 112, and the second inner circumferential surface 212B and the outer circumferential surface of the shaft 10 face each other through a minute gap filled with a fluid such as lubricating oil. Do. As the fluid, for example, a polyol ester oil and / or a diester lubricating fluid is used. A groove 21C recessed outward in the radial direction is provided between the second inner circumferential surface 211B and the second inner circumferential surface 212B in the axial direction. The groove 21C is a groove for circulating air for stabilizing the interface of the fluid.

  The first inner circumferential surface 211 </ b> A is a thrust bearing surface facing the outer circumferential surface 111 </ b> B of the annular member 11. The first inner circumferential surface 212 </ b> A is a thrust bearing surface facing the outer circumferential surface 112 </ b> B of the annular member 11. The second inner circumferential surfaces 211 </ b> B and 212 </ b> B are radial bearing surfaces facing the outer circumferential surface of the shaft 10. In the first inner circumferential surface 211A, 212A and the second inner circumferential surface 211B, 212B, a dynamic pressure groove array (not shown) for generating a dynamic pressure of fluid is respectively provided. The “fluid bearing” according to the present embodiment is configured by the shaft 10, the annular member 11, and the sleeve 21.

  A seal member 300 is provided on the axial upper side and the axial lower side of the sleeve 21 in order to prevent the lubricating fluid from leaking to the outside of the spindle motor 1. The seal member 300 covers the upper and lower surfaces of the annular member 11 and the sleeve 21, and is fixed to the sleeve 21.

  The outer hub 22 is a cylindrical member that annularly expands around the central axis 9 on the radially outer side of the sleeve 21. The outer hub 22 rotates around the central axis 9 together with the sleeve 21. In addition, the outer hub 22 has a flange portion 221 that extends outward in the radial direction from the outer peripheral surface of the lower portion.

  The clamp member 23 is supported by the outer hub 22. As shown in FIG. 1, the three magnetic disks 101 are held between the clamp member 23 and the flange portion 221 of the outer hub 22. Thus, the three magnetic disks 101 are supported by the rotating portion 20 and rotate around the central axis 9 together with the rotating portion 20.

  The rotor magnet 24 is fixed to the inner peripheral surface of the outer hub 22 via the yoke 25. The rotor magnet 24 has an annular shape centered on the central axis 9. The inner circumferential surface of the rotor magnet 24 is a magnetic pole surface in which N and S poles are alternately arranged along the circumferential direction.

  The stator unit 30 is disposed radially inward of the rotor magnet 24. The stator unit 30 generates a torque for rotating the rotating unit 20. The stator unit 30 has a stator core 31 and a plurality of coils 32.

  The stator core 31 is a laminated structure in which a plurality of annular magnetic bodies centered on the central axis 9 are laminated. The stator core 31 is fixed to the base 40. The stator core 31 has a plurality of teeth projecting radially outward.

  The plurality of coils 32 are wound around a plurality of teeth and arranged annularly around the central axis 9. The plurality of coils 32 are configured by three coil groups. The three coil groups are for U phase, V phase and W phase respectively. Each coil group is comprised by one conducting wire. The stator core 31 and the coil 32 and the rotor magnet 24 face each other in the radial direction.

  In such a spindle motor 1, when a drive current is supplied to the coil 32, radial magnetic flux is generated in a plurality of teeth. The magnetic flux generated in the teeth interacts with the magnetic flux of the rotor magnet 24 to generate a circumferential torque for rotating the rotating portion 20 around the central axis 9. As a result, with respect to the “stationary member” including the shaft 10 and the annular member 11, the “rotational member” including the sleeve 21 and the outer hub 22 rotates around the central axis 9. In addition, the three magnetic disks 101 supported by the rotating unit 20 rotate around the central axis 9 together with the rotating unit 20.

  When the spindle motor 1 rotates, dynamic pressure is generated in the fluid filled in a slight gap between the “stationary member” and the “rotation member” by the above-described dynamic pressure groove array (not shown). Thereby, the first inner peripheral surfaces 211A and 212A of the sleeve 21 are supported from the outer peripheral surfaces 111B and 112B of the annular member 11 in a noncontact manner in the thrust direction. Further, the second inner circumferential surfaces 211B and 212B of the sleeve 21 are supported from the outer circumferential surface of the shaft 10 in a non-contact manner in the radial direction. As described above, when the spindle motor 1 rotates, the rotational accuracy of the magnetic disk 101 that rotates with the rotating unit 20 is improved, and errors and damage when reading or writing the magnetic disk 101 are suppressed. There is a need to improve the assembly accuracy of each part forming a bearing. That is, it is required to improve the dimensional accuracy of the clearance in the thrust direction and the clearance in the radial direction of the bearing. In the following, a method of measuring a thrust gap with high accuracy between the first inner circumferential surfaces 211A and 212A of the sleeve 21 forming the bearing and the outer circumferential surfaces 111B and 112B of the annular member 11 will be described. Thus, the thrust gap can be adjusted with high accuracy based on the measurement result, and the final assembly accuracy of the bearing can be improved.

<1-3. Measurement method of thrust gap>
Hereinafter, a method of measuring the thrust gap between the first inner circumferential surfaces 211A and 212A of the sleeve 21 and the outer circumferential surfaces 111B and 112B of the annular member 11 will be described. 3 and 4 are cross-sectional views schematically showing how the thrust gap is measured.

  Hereinafter, the rotating body constituted by the sleeve 21 and the outer hub 22 will be referred to as a "hub 50". Moreover, in FIG. 3 and FIG. 4, the shape of each member is simplified and shown in figure. For example, in FIG. 2, the first inner peripheral surfaces 211A and 212A of the sleeve 21 and the outer peripheral surfaces 111B and 112B of the annular member 11 are inclined surfaces which are inclined with respect to the axial direction, respectively. In 4, it is illustrated as a plane perpendicular to the central axis 9. The upper surface of the hub 50 in FIGS. 3 and 4 shows the first inner peripheral surface 211A of the sleeve 21, and the lower surface of the hub 50 shows the first inner peripheral surface 212A of the sleeve 21. The lower surface of the upper ring 111 in FIGS. 3 and 4 shows the outer peripheral surface 111B of the annular member 11, and the upper surface of the lower ring 112 shows the outer peripheral surface 112B of the annular member 11. As shown in FIGS. 3 and 4, the shaft 10 is inserted into the through hole 210 of the hub 50, and the upper ring 111 is fixed to the shaft 10 by press fitting above the hub 50 in the axial direction. In the state where the lower ring 112 is fixed to the shaft 10 by press fitting, the measurement of the thrust gap is performed.

  The device for measuring the thrust gap has a main body 60, an air cylinder 61, a displacement gauge 62, an elastic member 63, and a hub fixing portion 64. The air cylinder 61, the displacement gauge 62, and the hub fixing portion 64 are each fixed to the main body 60. The main body 60 has an upper side wall portion 601 and a lower side wall portion 602. The upper side wall portion 601 extends in the radial direction on the upper side of the shaft 10. The lower side wall portion 602 extends in the radial direction below the shaft 10.

  The air cylinder 61 has a cylinder body 611, a cylinder displacement portion 612, and a cylinder contact portion 613. The air cylinder 61 displaces the cylinder displacement portion 612 in the axial direction by supplying and discharging air to the cylinder body 611. The cylinder main body 611 is fixed to the lower side wall portion 602 of the main body 60, and its axial and radial movements are restricted. A resin-made cylinder contact portion 613 having a large surface friction force is fixed to the upper end portion of the cylinder displacement portion 612. The lower surface of the shaft 10 contacts the cylinder contact portion 613. Thereby, the positional deviation of the shaft 10, damage and the like are suppressed.

  The displacement gauge 62 has a displacement gauge fixing portion 621, a displacement gauge displacement portion 622, and a displacement gauge contact portion 623. The displacement gauge fixing portion 621 is fixed to the upper side wall portion 601 of the main body 60, and the movement in the axial direction and the radial direction is limited. The displacement gauge displacement portion 622 is axially displaceably supported relative to the displacement gauge fixing portion 621. However, due to the engagement structure (not shown) provided between the upper end of the displacement gauge displacement portion 622 and the displacement gauge fixing portion 621, the displacement gauge displacement portion 622 may fall off the displacement gauge fixing portion 621 and fall It is suppressed. At the lower end portion of the displacement gauge displacement portion 622, a displacement gauge contact portion 623 made of resin having a large surface friction force is fixed. The upper surface of the shaft 10 contacts the displacement meter contact portion 623. Thereby, the positional deviation of the shaft 10, damage and the like are suppressed.

  As described above, at least a part of the displacement gauge displacement portion 622 is located between the displacement gauge fixing portion 621 and the displacement gauge contact portion 623 in the axial direction. The outer diameter of the displacement gauge displacement portion 622 is smaller than the outer diameter of the displacement gauge fixing portion 621 and the outer diameter of the displacement gauge contact portion 623. The elastic member 63 is attached in a state where the elastic member 63 is compressed in the axial direction more than the natural length between the radial outside of the displacement gauge displacement portion 622 and the axial direction between the displacement gauge fixing portion 621 and the displacement gauge contact portion 623 It is done. The upper end portion of the elastic member 63 is fixed to the displacement gauge fixing portion 621. The lower end portion of the elastic member 63 is fixed to the displacement meter contact portion 623. The displacement gauge displacement portion 622 extends downward by the elastic force E of the elastic member 63 in a state where no upward force is applied.

  The hub fixing portion 64 has a clamp structure. The hub fixing portion 64 sandwiches and fixes the hub 50 from the upper and lower sides in the axial direction, and restricts the axial and radial movement of the hub 50.

  FIG. 5 is a flow chart showing the process of measuring and adjusting the thrust gap. As shown in FIG. 5, at the time of measurement of the thrust gap, first, the hub 50 is fixed by the hub fixing portion 64, and axial movement of the hub 50 is limited (step S1). At this time, the upper end portion of the shaft 10 is indirectly brought into contact with the lower end portion of the elastic member 63 via the displacement meter contact portion 623. Further, the lower end portion of the shaft 10 is adjusted to be positioned directly above the cylinder contact portion 613.

  Next, the air cylinder 61 is driven to displace the cylinder displacement portion 612 upward. Then, the lower end portion of the shaft 10 is pushed upward via the cylinder contact portion 613 (step S2), and the lower ring 112 fixed to the shaft 10 is brought into contact with the hub 50. The upward force applied to the shaft 10 by pushing up the air cylinder 61 is defined as "force F".

  Return to FIG. FIG. 3 shows the state when step S2 is completed. The upper end portion of the shaft 10 at the end of step S2 has a height h1. In at least step S2, step S3 to be described later, and step S4 to be described later, a downward elastic force E is applied to the upper end portion of the shaft 10 by the elastic member 63. On the other hand, the magnitude of the upward force F applied to the shaft 10 by pushing up the air cylinder 61 is larger than the magnitude of the elastic force E. Thus, the shaft 10 can be pushed upward even in a state in which the downward elastic force E is applied to the shaft 10.

  After completion of step S2, the driving of the air cylinder 61 is stopped, and the cylinder displacement portion 612 is displaced downward. At this time, the downward elastic force E applied to the shaft 10 by the elastic member 63 is maintained. Thereby, the shaft 10 is pushed downward, and the upper ring 111 fixed to the shaft 10 is brought into contact with the hub 50 (step S3). Return to FIG. FIG. 4 shows the state when step S3 is completed. The upper end portion of the shaft 10 at the end of step S3 has a height h2.

  Furthermore, the displacement gauge 62 is an axial distance between the height h1 of the upper end of the shaft 10 at the end of step S2 and the height h2 of the upper end of the shaft 10 at the end of step S3 (shaft The movement distance D) of 10 is measured (step S4). Here, the movement distance D corresponds to an axial clearance dimension between the hub 50 and the upper ring 111 and the lower ring 112. Thus, by going through the process of step S1 to step S4, the gap size, that is, the first inner peripheral surface 211A, 212A of the sleeve 21 forming the fluid bearing, and the outer peripheral surface 111B, 112B of the annular member 11 The thrust gap between them can be measured with high accuracy.

  Note that the magnitude of the upward force F applied to the shaft 10 by pushing up the air cylinder 61 in step S2 is preferably, for example, 600 gf or less. Thereby, the floating of the hub 50 due to the force F being excessively increased can be suppressed.

  More preferably, the magnitude of the upward force F applied to the shaft 10 by pushing up the air cylinder 61 in step S2 is 350 gf or more and less than 450 gf. Furthermore, it is desirable that the magnitude of the elastic force E be 250 gf or more and less than 350 gf, and the difference between the magnitude of the force F and the magnitude of the elastic force E be 50 gf or more and less than 250 gf (particularly 100 gf or more). FIG. 6 is a diagram showing the result of analysis of the relationship between the magnitude of the elastic force E and the variation of the measurement result of the movement distance D (thrust gap) of the shaft 10. Further, FIG. 6 shows the results of analysis using three types of samples P, Q and R, respectively. As shown in FIG. 6, when the magnitude of the elastic force E is within a specific range X (250 gf or more and less than 350 gf in this embodiment) for all three types of samples P, Q and R, the moving distance D of the shaft 10 It can be seen that the variation in the results of measuring (thrust gap) is reduced. That is, the measurement error of the movement distance D (thrust gap) can be further suppressed. FIG. 7 is a diagram showing the result of analysis of the relationship between the difference between the magnitude of the force F and the magnitude of the elastic force E and the variation of the measurement result of the movement distance D (thrust gap) of the shaft 10. As shown in FIG. 7, when the difference between the magnitude of the force F and the magnitude of the elastic force E is within a specific range Y (more than 50 gf and less than 250 gf in this embodiment), the moving distance D of the shaft 10 (thrust gap It can be seen that the dispersion of the results of measuring) is reduced. That is, the measurement error of the movement distance D (thrust gap) can be further suppressed. In addition, when the force F is smaller than the specific range Y, the force F for pushing up the shaft 10 is not sufficient, and the position of the shaft 10 is not stable, so that it is considered that the measurement result tends to be uneven.

  Return to FIG. After completion of step S4, it is determined whether the measurement result of the movement distance D is within a predetermined tolerance, greater than a predetermined tolerance, or smaller than a predetermined tolerance (step S5). When it is determined that the measurement result of the movement distance D is larger than the predetermined allowable range, adjustment (steps S6 and S7) for reducing the thrust gap indicated by the movement distance D is performed.

  As adjustment for reducing the thrust gap, first, the upper ring 111 is fixed to restrict the axial movement of the upper ring 111 (step S6). Next, the lower end of the shaft 10 is pushed upward by pushing up the air cylinder 61 or the like (step S7). Thereby, the axial clearance dimension between the hub 50 and the upper ring 111 and the lower ring 112 can be reduced. After the adjustment of the thrust gap is completed, steps S1 to S5 are executed again to measure and judge the dimension of the axial gap between the hub 50 and the upper ring 111 and the lower ring 112.

  If it is determined in step S5 that the measurement result of the movement distance D is within the predetermined allowable range, it is determined that the adjustment of the thrust gap is not necessary, and the process proceeds to the next assembly process. On the other hand, when it is determined that the measurement result of the movement distance D is smaller than the predetermined allowable range, the hub 50 or the like is treated as being defective (unusable). As described above, the final assembling accuracy of the bearing can be improved by performing the adjustment again as necessary based on the result of measuring the thrust gap with high accuracy.

  In the flowchart shown in FIG. 5, the determination in step S5 is performed after one process of steps S1 to S4. However, the process of steps S1 to S4 may be performed multiple times before the process proceeds to step S5. Then, in step S5, the determination may be performed using data for a specific number of times from the measurement results of the moving distance D multiple times, and the determination may be performed using the average value of the measurement results of the moving distance D multiple times You may

<2. Modified example>
Although the exemplary embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments.

  In the above-described embodiment, in step S2 to step S4, the lower end portion of the elastic member 63 indirectly contacts the upper end portion of the shaft 10 via the displacement meter contact portion 623 and a downward elastic force E is applied. . However, the displacement meter contact portion 623 may not be provided, and the upper end portion of the shaft 10 may be in direct contact with the lower end portion of the elastic member 63.

  In the above embodiment, the displacement gauge 62 to which the elastic member 63 is attached is provided on the upper side of the shaft 10, and the air cylinder 61 provided on the lower side of the shaft 10 is used to push the shaft 10 upward. It was being done. However, this configuration may be upside down. FIG. 8 is a cross-sectional view schematically showing how a thrust gap is measured according to a modification. In the example of FIG. 8, the lower end portion of the shaft 10B contacts the displacement gauge contact portion 623B of the displacement gauge 62B provided below the shaft 10B. The elastic member 63B is attached to the displacement gauge displacement portion 622B in a state of being compressed in the axial direction more than the natural length. Further, the displacement gauge displacement portion 622B is supported by the displacement gauge fixing portion 621B so as to be capable of being displaced axially upward. Thereby, the displacement gauge displacement portion 622B is displaced upward by the elastic force E of the elastic member 63B in a state where a downward force is not applied, and the upward elastic force E is applied to the shaft 10B. The upper end portion of the shaft 10B contacts a cylinder contact portion 613B of an air cylinder 61B provided above the shaft 10B.

  Then, the hub 50B is fixed to limit axial movement of the hub 50B, the air cylinder 61B is driven to press the upper end of the shaft 10B downward, and the air cylinder 61B is stopped to drive the shaft 10B. Through the steps of pushing up and measuring the moving distance of the lower end of the shaft 10B, the thrust clearance of the fluid bearing can be measured.

  That is, according to the measuring method of the present invention, the hub has a through hole into which the shaft is inserted, the one side ring fixed to the shaft on one side in the axial direction with respect to the hub, and the shaft on the other side in the axial direction with respect to the hub A) fixing the hub to limit axial movement of the hub, and b) pushing the shaft to one side in the axial direction to fix the other ring to the hub. And c) after the step b), pressing the shaft to the other side in the axial direction to bring the one side ring into contact with the hub, and d) from the end of the step b) to the end of the step c) In the steps of measuring and performing the axial moving distance of one end of the shaft, at least steps b), c), and d), the other end of the elastic member to which the one end is fixed The by direct or indirect contact with the shaft, it is sufficient to give an elastic force E toward the other axial side to the shaft. Thereby, the axial clearance dimension between the hub and the one side ring and the other side ring, that is, the thrust clearance can be measured with high accuracy.

  In the above-mentioned embodiment and modification, a spindle motor was mentioned as an example and explained as an example of a "motor." However, the motor of the present invention may be used, for example, as a fan motor to provide an air flow.

  The detailed shapes of the motor and the disk drive may be different from the configurations and shapes shown in the drawings of the present application. In addition, each element appearing in the above-described embodiment and modification may be combined appropriately as long as no contradiction occurs.

  The present invention is applicable to measurement methods and adjustment methods.

DESCRIPTION OF SYMBOLS 1 spindle motor 9 central axis 10, 10B housing 11 annular member 20 rotation part 21 sleeve 21C groove 22 outer hub 23 clamp member 24 rotor magnet 25 yoke 30 stator unit 31 stator core 32 coil 40 base part 50, 50B hub 60 main body 61, 61B Air cylinder 62, 62B Displacement gauge 63, 63B Elastic member 64 Hub fixing portion 100 Disk drive device 101 Magnetic disk 102 Access portion 103 Housing 104 Cover portion 105 Spacer 106 Spacer 107 Head 108 Arm 108 Head moving mechanism 111 Upper ring 111A, 111B Outer circumference Surface 112 lower ring 112A, 112B outer peripheral surface 210 through hole 211A first inner peripheral surface 211B second inner peripheral surface 212A first inner peripheral surface 12B Second inner circumferential surface 221 Flange portion 300 Seal member 601 Upper side wall portion 602 Lower side wall portion 611 Cylinder body 612 Cylinder displacement portion 613 and 613B Cylinder contact portion 621 and 621B Displacement meter fixed portion 622 and 622B Displacement meter displacement portion 623 and 623B Displacement meter contact point D Travel distance E Elastic force F Force h1 Height h2 Height

Claims (11)

A shaft disposed along a central axis extending up and down;
A hub having a through hole into which the shaft is inserted;
A side ring fixed to the shaft on one side in the axial direction with respect to the hub;
The other side ring fixed to the shaft on the other side in the axial direction with respect to the hub;
A measuring method for measuring an axial clearance dimension between the hub and the one side ring and the other side ring in a motor having the
a) restricting the axial movement of the hub by fixing the hub;
b) pushing the shaft in one axial direction to bring the other ring into contact with the hub;
c) after the step b), pushing the shaft axially to the other side to bring the one side ring into contact with the hub;
d) measuring an axial movement distance of one end of the shaft from the end of the step b) to the end of the step c);
Have
In at least the step b), the step c), and the step d), the shaft is brought into contact with the shaft directly or indirectly by contacting the other end of the elastic member to which one end is fixed. Measurement method to give an elastic force E toward the other side in the axial direction. The measurement method according to claim 1, wherein
The movement distance is measured by a displacement gauge,
The displacement gauge is
Fixed part,
A contact portion axially displaceable with respect to the fixed portion and in contact with one end of the shaft;
Have
The measurement method, wherein the elastic member is attached between the fixing portion and the contact portion in a state of being compressed in the axial direction more than a natural length. The measurement method according to claim 1 or 2, wherein
In the step b), an air cylinder is pressed to the other end of the shaft. The measurement method according to claim 3, wherein
The magnitude | size of the force F which goes to the axial direction one side added to the said shaft by pressing of the said air cylinder is larger than the magnitude | size of the said elastic force E. The measurement method according to claim 3, wherein
The measuring method, wherein the magnitude of the force F directed to one side in the axial direction applied to the shaft by the pressing of the air cylinder is 600 gf or less. The measurement method according to claim 3, wherein
The measurement method, wherein the magnitude of the force F directed to one side in the axial direction applied to the shaft by the pressing of the air cylinder is 350 gf or more and less than 450 gf. The measurement method according to claim 4, wherein
The measurement method, wherein the difference between the magnitude of the force F and the magnitude of the elastic force E is 100 gf or more. The measurement method according to claim 4, wherein
The measuring method, wherein the difference between the magnitude of the force F and the magnitude of the elastic force E is 50 gf or more and less than 250 gf. The measurement method according to any one of claims 1 to 8, wherein
The measurement method, wherein the magnitude of the elastic force E is 250 gf or more and less than 350 gf. The measurement method according to any one of claims 1 to 9, wherein after the step d) e) the movement distance measured in the step d) is within a predetermined range, A method of measuring, comprising determining whether it is larger than a predetermined range or smaller than the predetermined range. The measurement method according to claim 10,
In the step e), when it is determined that the measurement result of the movement distance is larger than the predetermined range,
f) limiting axial movement of the shaft by fixing the shaft;
g) pressing the one side ring axially to the other side with respect to the shaft after the step f);
Run
h) performing the steps a) to e) again after the step g),
How to adjust.

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