Motors and rotary drive devices

Abstract

The present invention provides a motor having a structure that provides electrical conductivity between a rotating body and a stationary part. [Solution] The spindle motor 3 comprises a conductive member 130 that deforms when subjected to force, an end cap 100 to which the conductive member 130 is attached, and an upper conical bearing member 72 that contacts the conductive member 130 in a deformed state. The conductive member 130 has a mounting portion 131 attached to the end cap 100, and a deformable portion 132 extending from the mounting portion 131 that deforms when subjected to force and contacts the upper conical bearing member 72. The deformable portion 132 extends axially when not subjected to force, and deforms radially intersecting the axial direction when subjected to force, generating force by causing at least one of the end cap 100 and the upper conical bearing member 72 to rotate.

Description

Technical Field

[0006] , ,

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[0001] The present invention relates to a motor and a rotational drive device.

Background Art

[0002] Motors are known to include bearings and rotors. In such a motor, when the rotor rotates, a voltage may be applied to the rotor and the bearing. Here, when the conductivity of the rotor and the bearing is low, the rotor and the bearing are charged by the applied voltage. As a result, it is conceivable that discharge occurs from the rotor and the bearing toward another member, damaging the other member.

[0003] For example, Patent Document 1 discloses a current shunt ring fixed to a rotating shaft. This current shunt ring has a conductive segment that expands radially by the centrifugal force generated when the shaft rotates. When this conductive segment contacts the housing, the shaft and the housing are electrically connected. As a result, the occurrence of discharge from the shaft and the bearing is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in the technique described in Patent Document 1, the current shunt ring is configured to contact the shaft and the housing. It is also conceivable to provide such a conductive member at another part of the motor.

[0006] An object of the present invention is to provide a motor having a structure for electrically connecting a rotating body and a stationary part.

Means for Solving the Problems

[0007] To solve the above problems, a motor is provided comprising a conductive member that deforms when subjected to force, a first member to which the conductive member is attached, and a second member that contacts the conductive member in a deformed state, wherein the conductive member has a mounting portion attached to the first member and a deformable portion extending from the mounting portion that deforms when subjected to force and contacts the second member, and the deformable portion extends in a first direction when not subjected to force, and deforms in a second direction intersecting the first direction when subjected to force, thereby generating the force by the rotation of at least one of the first member and the second member. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a motor having a structure that electrically connects a rotating body and a stationary part. [Brief explanation of the drawing]

[0009] [Figure 1] This is a perspective view of the hard disk drive unit 1. [Figure 2] This is a partial cross-sectional view of the spindle motor 3. [Figure 3] This is an enlarged view of part III in Figure 2. [Figure 4] This is an enlarged view of section IV in Figure 2. [Figure 5] These are cross-sectional and bottom views of the conductive member 130. [Figure 6] This is a cross-sectional view of a conductive member 130 having a slit 135. [Figure 7] These are cross-sectional and bottom views of the conductive member 130 when one deformable portion 132 is provided at the end of the mounting portion 131. [Figure 8] This is a cross-sectional view of a conductive member 130 having a weight portion 136. [Figure 9] This figure shows the conductive member 130 shown in Figure 7 attached to the end cap 100. [Figure 10] This figure shows the conductive member 130 shown in Figure 7 attached to the outer edge portion 84. [Figure 11]It is a partial cross-sectional view of the spindle motor 203. [Figure 12] It is an enlarged view of part XII of FIG. 11. [Figure 13] It is a cross-sectional view and a bottom view of the conduction member 300. [Figure 14] It is a partial cross-sectional view of the spindle motor 403. [Figure 15] It is an enlarged view of part XV of FIG. 14. [Figure 16] It is a cross-sectional view of the motor 600. [Figure 17] It is an enlarged view of part XVII of FIG. 16. [Figure 18] It is an enlarged view of part XVIII of FIG. 16.

Mode for Carrying Out the Invention

[0010] =First Embodiment= Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, although various technically preferable limitations are imposed on the embodiments described below for carrying out the present invention, the scope of the present invention is not limited to the following embodiments and illustrated examples.

[0011] FIG. 1 is a perspective view showing the configuration of the hard disk drive 1. FIG. 2 is a partial cross-sectional view showing an example of the spindle motor 3 used in the hard disk drive 1.

[0012] Here, as shown in FIG. 2 and the like, the direction parallel to the central axis of the shaft 50 described later is the axial direction, the direction around the central axis of the shaft 50 is the circumferential direction, and the direction perpendicular to the axial direction is the radial direction. Also, for the sake of explanation, the axial direction is the vertical direction, the cover 20 side is the upper side, and the base plate 10 side is the lower side.

[0013] <Hard Disk Drive> The hard disk drive 1 (an example of a rotary drive device) includes a housing 2, a spindle motor 3, a recording disk 4, and a data reading / writing device 5.

[0014] The housing 2 is a box-shaped case that houses the spindle motor 3 and the like. The housing 2 comprises a base plate 10 and a cover 20. The base plate 10 has a box-like shape with one side open and a bottom. The cover 20 is fastened to the base plate 10 using screws 21, which are fasteners. A sealing means (not shown), such as a gasket or adhesive, is provided between the base plate 10 and the cover 20. As a result, the base plate 10 and the cover 20 form a housing 2 having an internal space S.

[0015] The internal space S of the housing 2 is filled with air or helium gas, which has a lower density than air. In addition to air or helium gas, the internal space S may also be filled with, for example, nitrogen gas or a mixture of helium and nitrogen gas. The internal space S houses the spindle motor 3, the recording disk 4, and the data reading / writing device 5.

[0016] The spindle motor 3 supports multiple recording disks 4 so that they can rotate. The detailed structure of the spindle motor 3 will be described later.

[0017] Multiple recording discs 4 are provided and supported by the spindle motor 3 so that their respective disc surfaces face each other. A gap is formed between each recording disc 4.

[0018] The data reading / writing device 5 records data to the recording disk 4 or reads data from the recording disk 4. The data reading / writing device 5 includes a pivot post 5a, a swing arm 5b, a voice coil motor 5c, and a magnetic head 5d.

[0019] The pivot post 5a pivotably supports multiple swing arms 5b. The pivot post 5a is a member that extends in the vertical direction. The pivot post 5a has a female threaded portion 5e on its upper surface. In this embodiment, the pivot post 5a is integrated with the base plate 10. However, the pivot post 5a may be configured as a separate part from the base plate 10 and attached to the base plate 10.

[0020] The voice coil motor 5c causes the swing arm 5b to oscillate around the pivot post 5a as the center of rotation. The voice coil motor 5c also causes the swing arm 5b to oscillate parallel to the surface of the recording disc 4.

[0021] The magnetic head 5d applies magnetism to the recording disk 4 and reads magnetism from the recording disk 4. The magnetic head 5d is located at the tip of the swing arm 5b. One magnetic head 5d is provided for each of the multiple recording disks 4, one for the front surface and one for the back surface.

[0022] The magnetic head 5d is located on a ramp mechanism 6, which is positioned away from the recording disk 4. The ramp mechanism 6 is the part that forms the retracted position of the magnetic head 5d. When the voice coil motor 5c is activated and the swing arm 5b swings, the magnetic head 5d moves from the ramp mechanism 6 to the surface above or under the back surface of the recording disk 4, or moves from the surface above or under the back surface of the recording disk 4 to the ramp mechanism 6.

[0023] When the spindle motor 3 rotates, the recording disk 4 also rotates. In this state, when the swing arm 5b swings, the magnetic head 5d moves from the lamp mechanism 6 to either the surface of the rotating recording disk 4 or the underside of its underside. The magnetic head 5d then applies magnetism to the recording disk 4 and records data onto the recording disk 4. The magnetic head 5d also reads magnetism from the recording disk 4 to read the data recorded on the recording disk 4. On the other hand, when the magnetic head 5d does not apply magnetism to the recording disk 4, or when the magnetic head 5d does not read magnetism from the recording disk 4, the swing arm 5b swings, and the magnetic head 5d moves from either the surface of the rotating recording disk 4 or the underside of its underside to the lamp mechanism 6.

[0024] <Spindle Motor> Next, the detailed configuration of the spindle motor 3 will be described. Figure 2 is a partial cross-sectional view of the spindle motor 3, the recording disk 4, and the cover 20. The spindle motor 3 comprises a stationary part 30 and a rotating part 40 that rotates relative to the stationary part 30 via a bearing mechanism.

[0025] (Stationary part) The stationary part 30 includes a base plate 10, a shaft 50, and a stator core 60.

[0026] The base plate 10 is a metal component. The base plate 10 has a through hole 11, a circumferential groove 12, and a circumferential wall 13.

[0027] The through-hole 11 is a hole for fixing the shaft 50. The through-hole 11 is provided so as to penetrate the base plate 10 in the axial direction. The through-hole 11 is cylindrical, and the inner diameter of the cylinder is approximately the same as or smaller than the outer diameter of the shaft 50. In this case, the shaft 50 is fixed into the through-hole 11 by press-fitting. The inner diameter of the cylinder of the through-hole 11 may be larger than the outer diameter of the shaft 50.

[0028] The circumferential groove 12 is formed on the radially outer side of the through hole 11. The circumferential groove 12 is an annular groove provided so as to be coaxial with the central axis of the through hole 11 when viewed in the axial direction.

[0029] The circumferential wall portion 13 is provided projecting upward in the axial direction from the bottom surface of the circumferential groove portion 12 when viewed in the axial direction. The circumferential wall portion 13 is an annular wall provided so as to be coaxial with the central axis of the through hole 11 when viewed in the axial direction. The diameter of the circumferential wall portion 13 is larger than the diameter of the through hole 11.

[0030] The shaft 50 is a cylindrical metal member. The shaft 50 has a through-hole insertion portion 51, a first mounting portion 52, and a second mounting portion 53 formed on it, starting from the lower end. These portions are spaced apart in the axial direction.

[0031] The through-hole insertion portion 51 is inserted into the through-hole 11 and joined. If the outer diameter of the through-hole insertion portion 51 is larger than the diameter of the through-hole 11, the through-hole insertion portion 51 is inserted into the through-hole 11 and joined, for example, by press-fitting. In this way, the shaft 50 is fixed and connected to the base plate 10. If the outer diameter of the through-hole insertion portion 51 is smaller than the diameter of the through-hole 11, the through-hole insertion portion 51 is inserted into the through-hole 11 and then joined to the through-hole 11 by a method such as adhesive bonding.

[0032] The lower conical bearing member 71 is fixed to the first mounting portion 52, and the upper conical bearing member 72 is fixed to the second mounting portion 53. The lower conical bearing member 71 and the upper conical bearing member 72 have conical outer surfaces, with the conical outer surfaces facing radially outward.

[0033] The stator core 60 is a component formed by stacking multiple annular electromagnetic steel sheets in the axial direction when viewed axially. The stator core 60 is placed inside the circumferential groove 12 and fixed by adhesive or other methods. The stator core 60 has pole teeth (salient poles) that extend radially outward and are arranged in multiple locations along the circumferential direction. Coils 61 are wound around the pole teeth. The stator core 60 generates magnetic flux when current flows through the coils 61.

[0034] (Rotating part) The rotating part 40 includes a rotor hub 80, a rotor magnet 90, an end cap 100, a spacer ring 110, a clamp 120, and a conductive member 130.

[0035] The rotor hub 80 is a component that rotates relative to the shaft 50. The rotor hub 80 has an inner cylindrical wall portion 81, a disc portion 82, an outer cylindrical wall portion 83, and an outer edge portion 84.

[0036] The inner cylindrical wall portion 81 is a substantially cylindrical member. A rotor hub through hole 85 is formed at the center of the inner cylindrical wall portion 81 (the part corresponding to the rotation center of the rotor hub 80), and penetrates the rotor hub 80 in the axial direction. The shaft 50 is inserted through the rotor hub through hole 85. The rotor hub through hole 85 has a lower conical inner surface 86 at its lower end and an upper conical inner surface 87 at its upper end.

[0037] The inner surface 86 of the lower cone faces the lower conical bearing member 71 via a small gap 140a. The inner surface 87 of the upper cone faces the upper conical bearing member 72 via a small gap 140b.

[0038] The disc portion 82 is a disc-shaped member that is coaxial with the center of the inner cylindrical wall portion 81 when viewed in the axial direction. The disc portion 82 is formed radially outward from the inner cylindrical wall portion 81.

[0039] The outer cylindrical wall portion 83 is a cylindrical member having thickness in the radial direction. The outer cylindrical wall portion 83 is provided so as to be coaxial with the center of the inner cylindrical wall portion 81 in an axial view, and protrudes downward in the axial direction. The outer cylindrical wall portion 83 is provided on the outer edge of the disc portion 82.

[0040] The outer edge portion 84 is an annular member. The outer edge portion 84 is provided at the lower end of the outer cylindrical wall portion 83. The outer edge portion 84 protrudes radially outward from the outer cylindrical wall portion 83 and is formed in a flange shape. Multiple recording disks 4 are installed above the outer edge portion 84 and radially outward from the outer cylindrical wall portion 83.

[0041] Multiple recording discs 4 are installed so as to be stacked in the axial direction. A spacer ring 110 is placed between two axially adjacent recording discs 4, creating a gap. In other words, the recording discs 4 and spacer rings 110 are stacked alternately in the axial direction. The multiple recording discs 4 and spacer rings 110 stacked in this manner are fixed to the rotor hub 80 by clamps 120 attached to the upper surface of the rotor hub 80 with screws 121. Here, the multiple recording discs 4, spacer rings 110 and clamps 120 fixed to the rotor hub 80, which is part of the rotating part 40, rotate in conjunction with the rotation of the rotor hub 80.

[0042] The rotor magnet 90 is an annular member having a magnetic pole structure in which the polarity reverses along the circumferential direction in an axial view, in the order N, S, N, S…. The rotor magnet 90 is attached to the inner circumferential surface of the outer cylindrical wall portion 83.

[0043] The end cap 100 is an annular member fixed to the inner cylindrical wall portion 81. The end cap 100 has a through hole in its center when viewed axially. The shaft 50 is inserted through the through hole in the end cap 100. A small gap is formed between the end cap 100 and the shaft 50 so that the end cap 100 does not obstruct the rotation of the rotor hub 80. The end cap 100 is fixed to the upper and lower ends of the inner cylindrical wall portion 81 of the rotor hub 80, respectively, by adhesive, or by adhesive and press-fitting.

[0044] Lubricating oil is filled into the minute gaps 140a and 140b. Furthermore, a dynamic pressure generating groove (not shown) is formed on at least one of the lower cone inner surface 86 and the lower cone bearing member 71, and on at least one of the upper cone inner surface 87 and the upper cone bearing member 72. This forms a fluid dynamic pressure bearing 141.

[0045] [Conductive material] The conductive member 130 makes two members electrically connected by contacting them. The conductive member 130 is formed of a material in which all parts are conductive, or is configured such that a conductive path is formed between the parts that contact the two members. The conductive member 130 is a material that contains electrically conductive materials such as metals such as brass, aluminum, and stainless steel, or polymer compounds such as polyacetylene and polythiophene. As shown in Figures 3 and 4, the conductive member 130 is attached to the end cap 100 and the outer edge portion 84 (both examples of the first member). The conductive member 130 has a mounting portion 131 and a deformable portion 132. Figure 5 shows a conductive member 130 attached to the end cap 100 as an example of the conductive member 130. Figure 5(a) is a cross-sectional view of the conductive member 130, and Figure 5(b) is a bottom view of the conductive member 130.

[0046] The mounting portion 131 is a part that is attached to another member. The mounting portion 131 has a flat plate portion 133 and a cylindrical portion 134.

[0047] The flat plate portion 133 is a plate-shaped member formed in an annular shape. The upper or lower surface of the flat plate portion 133 is fixed to the member to which the mounting portion 131 is to be fixed by a method such as bonding with a conductive adhesive.

[0048] The cylindrical portion 134 is a part that protrudes from the flat plate portion 133. The cylindrical portion 134 extends from the outer or inner edge of the flat plate portion 133 in a direction perpendicular to the flat plate portion 133, i.e., in the axial direction. Furthermore, the cylindrical portion 134 extends circumferentially along the outer or inner edge of the flat plate portion 133. The cylindrical portion 134 is provided around the entire circumference of the outer or inner edge of the flat plate portion 133 and has a cylindrical shape.

[0049] The deformable portion 132 is a member that deforms when subjected to force and comes into contact with another member. The deformable portion 132 is provided at the end of the cylindrical portion 134 that is not continuous with the flat plate portion 133 (i.e., the lower end of the cylindrical portion 134). The deformable portion 132 extends axially from the lower end of the cylindrical portion 134. Thus, when not subjected to force, the deformable portion 132 extends axially. The deformable portion 132 is provided at the lower end of the cylindrical portion 134, extending almost the entire circumference in the circumferential direction. The deformable portion 132 has a slit 135. The deformable portion 132 may also be divided into multiple parts in the circumferential direction and provided at intervals in the circumferential direction. In this case, the deformable portion 132 does not have a slit 135.

[0050] At least one slit 135 is provided in the deformable portion 132, which extends substantially around the entire circumference in the circumferential direction. The slit 135 divides the deformable portion 132 in the circumferential direction. The slit 135 extends axially from the lower end to the upper end of the deformable portion 132. By providing the slit 135 in the deformable portion 132, the deformable portion 132 becomes capable of deforming when subjected to force. In the conductive member 130 shown in Figures 5(a) and 5(b), the deformable portion 132 deforms in a direction intersecting the axial direction, with the end on the side continuous with the cylindrical portion 134 fixed. It is preferable that the slit 135 has a shape in which the length of the lower end (width of the slit at the lower end) is shorter than the length of the upper end (width of the slit at the upper end), as shown in Figure 6.

[0051] The shape of the conductive member 130 is not limited to the shape described above. Specific shapes will be described in the embodiments below, but the conductive member 130 may have a mounting portion 131 composed of only one of either a flat plate portion 133 or a cylindrical portion 134, with a deformable portion 132 extending from either the flat plate portion 133 or the cylindrical portion 134. Furthermore, the mounting portion 131 and the deformable portion 132 may not be annular, but rather rectangular plate members or rod-shaped members.

[0052] In this embodiment, the conductive member 130 attached to the end cap 100 is attached with a conductive adhesive or the like so that the lower surface of the flat plate portion 133 contacts the upper surface of the end cap 100, as shown in Figure 3(a). The cylindrical portion 134 is positioned to contact the radially inner surface of the through hole in the end cap 100. Alternatively, a conductive adhesive or the like may be applied to the radially outer surface of the cylindrical portion 134 to attach it to the radially inner surface of the through hole in the end cap 100. The deformable portion 132 is provided at the lower end of the cylindrical portion 134, extending substantially around its entire circumference. This deformable portion 132 has two slits 135. In the deformable portion 132, the two slits 135 are provided at 180-degree intervals in the circumferential direction.

[0053] Furthermore, the conductive member 130 attached to the outer edge portion 84 is attached with a conductive adhesive or the like so that the lower surface of the flat plate portion 133 contacts the upper surface of the outer edge portion 84, as shown in Figure 4(a). The cylindrical portion 134 is positioned to contact the radially outer surface of the outer edge portion 84. Alternatively, a conductive adhesive or the like may be applied to the radially inner surface of the cylindrical portion 134 to attach it to the radially outer surface of the outer edge portion 84. The deformable portion 132 is provided at the lower end of the cylindrical portion 134, extending almost the entire circumference in the circumferential direction. This deformable portion 132 has two slits 135. In the deformable portion 132, the two slits 135 are provided at 180-degree intervals in the circumferential direction.

[0054] As shown in Figure 7, in the conductive member 130, at least one deformable portion 132 may be provided at the end of the cylindrical portion 134 that is not continuous with the flat plate portion 133 (i.e., the lower end of the cylindrical portion 134). Figure 7(a) is a cross-sectional view of the conductive member 130, and Figure 7(b) is a bottom view of the conductive member 130. The deformable portion 132 extends axially from any part of the lower end of the cylindrical portion 134. In such a conductive member 130, it is preferable that the deformable portion 132 has a weight portion 136 at its lower end (the end that is not continuous with the cylindrical portion 134), as shown in Figure 8.

[0055] Figure 9(a) shows the conductive member 130 shown in Figure 7 attached to the end cap 100. Figure 10(a) also shows the conductive member 130 shown in Figure 7 attached to the outer edge portion 84.

[0056] <Spindle motor operation> When current is applied to the coil 61, the magnetic attraction and repulsion forces between the magnetic poles of the rotor magnet 90 and the pole teeth of the stator core 60 switch. As a result, the rotating part 40 rotates around the shaft 50.

[0057] As the rotor hub 80 of the rotating part 40 rotates at high speed, the lubricating oil filled in the minute gap 140a between the lower conical inner surface 86 and the lower conical bearing member 71, and the minute gap 140b between the upper conical inner surface 87 and the upper conical bearing member 72, is pressurized by the dynamic pressure generating groove. As a result, dynamic pressure is generated in the fluid dynamic bearing 141. Due to the generated dynamic pressure, the rotor hub 80 rotates while being supported in a non-contact state with respect to the shaft 50, the lower conical bearing member 71, and the upper conical bearing member 72.

[0058] When the rotating part 40 rotates, a radial centrifugal force acts on the conductive member 130 that intersects with the axial direction in which the deformable part 132 extends. As a result, the deformable part 132 deforms in a direction intersecting with the axial direction. Specifically, as shown in Figure 3(b), the deformable part 132 of the conductive member 130 attached to the end cap 100 deforms in a direction intersecting with the axial direction and comes into contact with the upper conical bearing member 72. Also, as shown in Figure 4(b), the deformable part 132 of the conductive member 130 attached to the outer edge 84 deforms and comes into contact with the base plate 10. Note that the direction intersecting with a certain direction (for example, the axial direction) does not need to be parallel to the direction in which the deformable part 132 extends (the axial direction in this embodiment).

[0059] Furthermore, if a conductive member 130 as shown in Figure 7 is attached to the end cap 100, as shown in Figure 9(b), when the rotating part 40 rotates, the deformable part 132 deforms and comes into contact with the upper conical bearing member 72. Also, if a conductive member 130 as shown in Figure 7 is attached to the outer edge 84, as shown in Figure 10(b), when the rotating part 40 rotates, the deformable part 132 deforms and comes into contact with the base plate 10.

[0060] When the rotating part 40 rotates, it may become charged. As a result, unintended discharge may occur from the rotating part 40 toward nearby components, potentially damaging them. In this embodiment, the spindle motor 3 deforms as the rotating part 40 rotates, causing it to contact both the components of the rotating part 40 (end cap 100 and outer edge 84) and the components of the stationary part 30 (upper conical bearing member 72 and base plate 10). Therefore, the charge accumulated in the rotating part 40 flows to the stationary part 30 through the conductive member 130. Consequently, unintended discharge from the rotating part 40 toward nearby components is less likely to occur.

[0061] In particular, as shown in Figure 6, when the length of the lower end of the slit 135 (the width of the slit at the lower end) is shorter than the length of the upper end (the width of the slit at the upper end), the lower side of the deformed portion 132 becomes heavier than the upper side of the deformed portion 132. Therefore, a greater centrifugal force is more likely to be applied to the lower side of the deformed portion 132, causing the deformed portion 132 to deform more easily in the radial direction. As a result, the deformed portion 132 is more likely to come into contact with the member of the stationary portion 30, making it even less likely for unintended discharges to occur from the rotating portion 40 toward nearby members.

[0062] Furthermore, in the case of the conductive member 130 as shown in Figure 8, since the deformable portion 132 has a weight portion 136 at its lower end (the end not continuous with the cylindrical portion 134), a greater centrifugal force is easily applied to the lower side of the deformable portion 132. Therefore, the deformable portion 132 is more likely to deform in the radial direction. As a result, the deformable portion 132 is more likely to come into contact with the member of the stationary portion 30, making it even less likely for unintended discharges to occur from the rotating portion 40 toward nearby members.

[0063] =Second Embodiment= Next, the spindle motor 203 of the second embodiment will be described. The spindle motor 203 is a shaft-mounted motor, similar to the spindle motor 3.

[0064] <Spindle Motor> Figure 11 is a partial cross-sectional view of the spindle motor 203. The spindle motor 203 comprises a stationary part 230 and a rotating part 240 that rotates relative to the stationary part 230 via a bearing mechanism.

[0065] (Stationary part) The stationary section 230 includes a base plate 210, a sleeve 250, a stator core 260, and a shaft 270.

[0066] The base plate 210 is a metal component. The base plate 210 has a through hole 211, a circumferential groove 212, and a circumferential wall 213.

[0067] The through-hole 211 is a hole for fixing the sleeve 250. The through-hole 211 is provided so as to penetrate the base plate 210 in the axial direction. The through-hole 211 is cylindrical, and the inner diameter of the cylinder is approximately the same as or larger than the outer diameter of the sleeve 250.

[0068] The circumferential groove 212 is formed on the radially outer side of the through hole 211. The circumferential groove 212 is an annular groove provided so as to be coaxial with the central axis of the through hole 211 when viewed in the axial direction.

[0069] The circumferential wall portion 213 is formed as an annular wall portion that protrudes axially upward from the bottom surface of the circumferential groove portion 212 along the through hole 211 when viewed in the axial direction. The circumferential wall portion 213 separates the through hole 211 and the circumferential groove portion 212.

[0070] The sleeve 250 fixes the shaft 270 to the base plate 210 and forms a dynamic pressure bearing between itself and the rotating part 240. The sleeve 250 is a cylindrical iron component such as stainless steel. The sleeve 250 is inserted into the through hole 211. The sleeve 250 is fixed to the through hole 211 by adhesive applied to one or both sides of the outer surface of the sleeve 250 and the inner surface of the through hole 211. The sleeve 250 has a sleeve through hole 251 and a sleeve recess 252.

[0071] The sleeve through-hole 251 is located at the center of the sleeve 250 in an axial view and is provided to penetrate the sleeve 250 in the axial direction. The diameter of the sleeve through-hole 251 is approximately the same as, or larger than, the outer diameter of the shaft 270.

[0072] The sleeve recess 252 is a circular recess formed in the sleeve 250 in an axial view. The sleeve recess 252 is provided coaxially with the central axis of the sleeve through-hole 251 in an axial view. The sleeve recess 252 connects to the sleeve through-hole 251 and is formed on the upper side of the sleeve through-hole 251. A thrust dynamic pressure generating groove 253 is formed on the bottom surface of the sleeve recess 252. The thrust dynamic pressure generating groove 253 is provided in an annular shape in an axial view.

[0073] The stator core 260 is a component formed by stacking multiple annular electromagnetic steel sheets in the axial direction when viewed axially. The stator core 260 is placed inside the circumferential groove 212 and fixed by methods such as adhesive bonding. The stator core 260 has pole teeth (salient poles) that extend radially outward and are arranged in multiple locations along the circumferential direction. Coils 261 are wound around the pole teeth. The stator core 260 generates magnetic flux when current flows through the coils 261.

[0074] The shaft 270 is a cylindrical metal member. The outer diameter of the shaft 270 is approximately the same as, or smaller than, the inner diameter of the sleeve through-hole 251. The lower end of the shaft 270 is inserted into the sleeve through-hole 251. The shaft 270 is fixed to the sleeve through-hole 251 by adhesive applied to one or both sides of the outer circumferential surface of the shaft 270 and the inner circumferential surface of the sleeve through-hole 251, and is connected to the sleeve 250. The shaft 270 has a radial dynamic pressure generating groove 271 and a flange portion 272.

[0075] The radial dynamic pressure generating grooves 271 are provided on the outer circumferential surface of the shaft 270 in the portion inserted into the rotor hub 280, which will be described later. In this modified example, the radial dynamic pressure generating grooves 271 are formed on the outer circumferential surface of the shaft 270 in a continuous row in the circumferential direction, and two rows are formed with an interval between them in the axial direction.

[0076] The flange portion 272 is formed integrally with the shaft 270 near the upper end of the shaft 270. The flange portion 272 is a member that extends radially outward from the shaft 270. The flange portion 272 has a thrust dynamic pressure generating groove 273.

[0077] The thrust dynamic pressure generating groove 273 is formed on the lower surface of the flange portion 272. The thrust dynamic pressure generating groove 273 is provided in an annular shape when viewed in the axial direction.

[0078] The rotating part 240 includes a rotor hub 280, a rotor magnet 290, and a conductive member 300.

[0079] The rotor hub 280 is a component that rotates relative to the sleeve 250 and the shaft 270. The rotor hub 280 is positioned on the outside of the shaft 270, with a portion of its lower side positioned in the sleeve recess 252. The rotor hub 280 has an inner cylindrical wall portion 281, a disc portion 282, an outer cylindrical wall portion 283, an outer edge portion 284, and an enlarged diameter portion 286.

[0080] The inner cylindrical wall portion 281 is a substantially cylindrical member. A gap 310a is formed between the lower end surface of the inner cylindrical wall portion 281 and the bottom surface of the sleeve recess 252 of the sleeve 250. A rotor hub through hole 285 is formed at the center of the inner cylindrical wall portion 281 (the part corresponding to the rotation center of the rotor hub 280), and penetrates the rotor hub 280 in the axial direction. The diameter of the rotor hub through hole 285 is larger than the outer diameter of the shaft 270. The shaft 270 is inserted into the rotor hub through hole 285. A gap 310b is formed between the inner circumferential surface of the rotor hub through hole 285 and the outer circumferential surface of the shaft 270.

[0081] The disc portion 282 is a disc-shaped member that is coaxial with the center of the inner cylindrical wall portion 281 when viewed in the axial direction. The disc portion 282 is formed radially outward from the upper end side of the inner cylindrical wall portion 281.

[0082] The outer cylindrical wall portion 283 is a cylindrical member having thickness in the radial direction. The outer cylindrical wall portion 283 is provided so as to be coaxial with the center of the inner cylindrical wall portion 281 in an axial view, and protrudes in the axial direction. The outer cylindrical wall portion 283 is provided on the outer edge of the disc portion 282.

[0083] The outer edge portion 284 is an annular member. The outer edge portion 284 is provided at the lower end of the outer cylindrical wall portion 283. The outer edge portion 284 protrudes radially outward from the outer cylindrical wall portion 283 and is formed in a flange shape. Multiple recording disks 4 are installed above the outer edge portion 284 and radially outward from the outer cylindrical wall portion 283 (see Figure 1).

[0084] The enlarged diameter portion 286 is a cylindrical member having thickness in the radial direction. The enlarged diameter portion 286 is provided below the disc portion 282 and radially outward from the inner cylindrical wall portion 281. The outer diameter of the enlarged diameter portion 286 is smaller than the inner diameter of the circumferential wall portion 213.

[0085] The rotor magnet 290 is an annular member having a magnetic pole structure in which the polarity reverses along the circumferential direction in an axial view, in the order N, S, N, S…. The rotor magnet 290 is attached to the inner circumferential surface of the outer cylindrical wall portion 283. The rotor magnet 290 is located in approximately the same position as the stator core 260 in the axial direction.

[0086] Lubricating oil is filled between the rotor hub 280 and the sleeve 250, and between the rotor hub 280 and the shaft 270. Specifically, lubricating oil is filled into the gaps 310a and 310b and the gap between the lower surface of the flange portion 272 and the rotor hub 280.

[0087] [Conductive material] The conductive member 300 makes two members electrically connected by contacting them. The conductive member 300 is made of a conductive material, or is configured such that a conductive path is formed between the parts that contact the two members. The conductive member 300 is a material that easily conducts electricity, such as metals such as brass, aluminum, and stainless steel, or polymer compounds such as polyacetylene and polythiophene. As shown in Figure 12, the conductive member 300 is attached to the enlarged diameter portion 286. The conductive member 300 has a mounting portion 301 and a deformable portion 302. Figure 13 shows an example of a conductive member 300 attached to the enlarged diameter portion 286. Figure 13(a) is a cross-sectional view of the conductive member 300, and Figure 13(b) is a bottom view of the conductive member 300.

[0088] The mounting portion 301 is a part that is attached to another member. The mounting portion 301 is a plate-shaped member formed in an annular shape. The mounting portion 301 has a shape that does not have a cylindrical portion 134 (i.e., only a flat plate portion 133) compared to the mounting portion 131 of the first embodiment. The upper or lower surface of the mounting portion 301 is fixed to the member to which the mounting portion 301 is to be fixed by a method such as bonding with a conductive adhesive.

[0089] The deformable portion 302 is a member that deforms when subjected to force and comes into contact with another member. At least one deformable portion 302 is provided at any point on the radial outer or inner edge of the annular mounting portion 301. The deformable portion 302 extends axially from the mounting portion 301. The deformable portion 302 may have a weight portion 136 at its lower end (the end not continuous with the mounting portion 301) (see Figure 8).

[0090] In this embodiment, the conductive member 300 attached to the enlarged diameter portion 286 is attached with a conductive adhesive or the like so that the upper surface of the mounting portion 301 is in contact with the lower surface of the enlarged diameter portion 286, as shown in Figure 12(a). The outer diameter of the mounting portion 301 is approximately equal to the outer diameter of the enlarged diameter portion 286. One deformable portion 302 is provided so as to extend downward from the outer edge of the mounting portion 301.

[0091] <Spindle motor operation> When current is applied to the coil 261, the magnetic attraction and repulsion forces between the magnetic poles of the rotor magnet 290 and the pole teeth of the stator core 260 switch. As a result, the rotating part 240 rotates around the shaft 270 relative to the stationary part 230.

[0092] The rotor hub 280 rotates relative to the shaft 270. During this rotation, the lubricating oil is pressurized by the radial dynamic pressure generating groove 271 and the thrust dynamic pressure generating groove 273, generating dynamic pressure in the lubricating oil. The dynamic pressure generated by the radial dynamic pressure generating groove 271 supports the rotor hub 280 radially in a non-contact manner relative to the shaft 270. In addition, the dynamic pressure generated by the thrust dynamic pressure generating groove 273 supports the rotor hub 280 axially in a non-contact manner relative to the shaft 270.

[0093] The rotor hub 280 rotates relative to the sleeve 250. During this rotation, the lubricating oil is pressurized by the thrust dynamic pressure generating groove 253, generating dynamic pressure in the lubricating oil. The dynamic pressure generated by the thrust dynamic pressure generating groove 253 supports the rotor hub 280 in a non-contact manner in the axial direction relative to the sleeve 250.

[0094] When the rotating part 240 rotates, a radial centrifugal force acts on the conductive member 300, intersecting the axial direction in which the deformable part 302 extends. As a result, the deformable part 302 deforms in a direction intersecting the axial direction. Specifically, as shown in Figure 12(b), the deformable part 302 of the conductive member 300 attached to the enlarged diameter part 286 deforms in a direction intersecting the axial direction and comes into contact with the circumferential wall part 213 of the base plate 210. Note that the direction intersecting a certain direction (for example, the axial direction) does not need to be parallel to the direction in which the deformable part 302 extends (the axial direction in this embodiment).

[0095] When the rotating part 240 rotates, it may become charged. As a result, unintended discharge may occur from the rotating part 240 toward nearby components, potentially damaging them. In this embodiment, the spindle motor 203 deforms as the rotating part 240 rotates, causing the conductive member 300 to contact both the components of the rotating part 240 (the enlarged diameter portion 286 of the rotor hub 280) and the components of the stationary part 230 (the circumferential wall portion 213 of the base plate 210). Therefore, the charge accumulated on the rotating part 240 flows to the stationary part 230 through the conductive member 300. Consequently, unintended discharge from the rotating part 240 toward nearby components is less likely to occur.

[0096] =Third Embodiment= Next, the spindle motor 403 of the third embodiment will be described. The spindle motor 403 is the fan motor of the blower. Here, in the third embodiment, components similar to those in the second embodiment are denoted by the same reference numerals as in the second embodiment, and detailed descriptions are omitted.

[0097] As shown in Figure 14, the spindle motor 403 comprises a stationary part 430 and a rotating part 440 that rotates relative to the stationary part 430 via a bearing mechanism.

[0098] (Stationary part) The stationary section 430 includes a base plate 410, a bearing sleeve 450, and a stator core 460.

[0099] The base plate 410 is a metal component. The base plate 410 has a through hole 411, a circumferential groove 412, a circumferential wall 413, and a plate recess 414.

[0100] The through-hole 411 is a hole for fixing the bearing sleeve 450. The through-hole 411 is provided so as to penetrate the base plate 410 in the axial direction. The through-hole 411 is cylindrical, and the inner diameter of the cylinder is approximately the same as or larger than the outer diameter of the bearing sleeve 450.

[0101] The circumferential groove 412 is formed on the radially outer side of the through hole 411. The circumferential groove 412 is an annular groove provided so as to be coaxial with the central axis of the through hole 411 when viewed in the axial direction.

[0102] The circumferential wall portion 413 is formed radially outside the through hole 411 and inside the circumferential groove portion 412. The circumferential wall portion 413 is an annular wall provided so as to be coaxial with the central axis of the through hole 411 in an axial view, and it protrudes upward in the axial direction.

[0103] The plate recess 414 is formed radially inward of the circumferential wall portion 413. The plate recess 414 is a cylindrical space provided so as to be coaxial with the central axis of the through hole 411 in an axial view, and it opens upward. The diameter of the plate recess 414 is larger than the outer diameter of the through hole 411. The plate recess 414 is connected axially to the upper side of the through hole 411.

[0104] The bearing sleeve 450 rotatably supports the shaft 470, which will be described later. The bearing sleeve 450 is a cylindrical iron component such as stainless steel. The bearing sleeve 450 is inserted into the through hole 411. The bearing sleeve 450 is fixed to the through hole 411 by adhesive applied to one or both sides of the outer circumferential surface of the bearing sleeve 450 and the inner circumferential surface of the through hole 411. The bearing sleeve 450 is provided with a radial dynamic pressure generating groove 451 and a thrust dynamic pressure generating groove 452.

[0105] The radial dynamic pressure generating grooves 451 are provided on the inner circumferential surface 450a of the bearing sleeve 450. In this embodiment, the radial dynamic pressure generating grooves 451 are formed on the inner circumferential surface 450a in a continuous row in the circumferential direction, and two rows are formed with an interval between them in the axial direction.

[0106] The thrust dynamic pressure generating groove 452 is provided on the end face 454 of the axially upper sleeve end 453a of the bearing sleeve 450. The thrust dynamic pressure generating groove 452 is provided in an annular shape so as to be coaxial with the central axis of the bearing sleeve 450 when viewed in the axial direction.

[0107] A large-diameter recess 455 and a small-diameter recess 456 are formed axially in a continuous manner at the axial lower sleeve end 453b of the bearing sleeve 450. A counter plate 457 is attached to the large-diameter recess 455.

[0108] The large-diameter recess 455 is formed at the sleeve end 453b. The large-diameter recess 455 is a cylindrical space provided so as to be coaxial with the central axis of the through hole 411 in an axial view. The large-diameter recess 455 opens downward.

[0109] The small-diameter recess 456 is formed on the upper side of the large-diameter recess 455 at the sleeve end 453b. The small-diameter recess 456 is a cylindrical space provided so as to be coaxial with the central axis of the through hole 411 in an axial view. The small-diameter recess 456 is connected to the large-diameter recess 455 in the axial direction. The diameter of the small-diameter recess 456 is smaller than the diameter of the large-diameter recess 455. As a result of the formation of the small-diameter recess 456 at the sleeve end 453b, the bearing sleeve 450 has an annular surface 458 in an axial view and an inner circumferential surface 459 in the circumferential direction.

[0110] The counter plate 457 is a disc-shaped cover inserted into the large-diameter recess 455 from below the sleeve end 453b. The counter plate 457 closes the large-diameter recess 455 and the small-diameter recess 456. The counter plate 457 is made of iron, such as stainless steel. The outer diameter of the counter plate 457 is approximately equal to the inner diameter of the large-diameter recess 455. The axial thickness of the counter plate 457 is approximately equal to the depth of the large-diameter recess 455.

[0111] When the counter plate 457 is inserted into the large-diameter recess 455, the outer edge of the counter plate 457 and the inner edge of the large-diameter recess 455 are joined by laser welding. In this way, the counter plate 457 is fixed to the bearing sleeve 450 without any gaps and closes the large-diameter recess 455 and the small-diameter recess 456.

[0112] The stator core 460 is a component formed by stacking multiple annular electromagnetic steel sheets in the axial direction when viewed axially. The stator core 460 is placed inside the circumferential groove 412 and fixed by methods such as adhesive bonding. The stator core 460 has pole teeth (salient poles) that extend radially outward and are arranged in multiple locations along the circumferential direction. Coils 461 are wound around the pole teeth. The stator core 460 generates magnetic flux when current flows through the coils 461.

[0113] (Rotating part) The rotating part 440 includes a shaft 470, a rotor hub 480, a rotor magnet 490, and a conductive member 300.

[0114] The shaft 470 is the rotating axis component of the spindle motor 403. The shaft 470 is rotatably supported inside the bearing sleeve 450. The shaft 470 has a columnar shaft portion 471 and a flange portion 472. The shaft portion 471 and the flange portion 472 of the shaft 470 are integrated.

[0115] The shaft portion 471 is a cylindrical shaft member. The shaft portion 471 has a flange portion 472 integrally attached to its lower shaft end portion 473. The shaft portion 471 is positioned inside the bearing sleeve 450 with the shaft end portion 473, to which the flange portion 472 is attached, facing downwards. In other words, the outer circumferential surface of the shaft portion 471 is surrounded by the inner circumferential surface 450a of the bearing sleeve 450. The outer circumferential surface of the shaft portion 471 and the inner circumferential surface 450a of the bearing sleeve 450 face each other with a small gap between them. Alternatively, instead of the inner circumferential surface 450a of the bearing sleeve 450, a radial dynamic pressure generating groove 451 may be formed on the outer circumferential surface of the shaft portion 471.

[0116] The flange portion 472 is an annular flange member that expands radially in an axial view. The flange portion 472 is positioned in the small-diameter recess 456 when the shaft 470 is supported by the bearing sleeve 450. The outer diameter of the flange portion 472 is smaller than the inner diameter of the small-diameter recess 456. The upper surface of the flange portion 472 faces the annular surface 458 formed by the small-diameter recess 456 on the bearing sleeve 450, separated by a small gap. The lower surface of the flange portion 472 faces the upper surface of the counter plate 457, separated by a small gap. The side surface of the flange portion 472 faces the inner circumferential surface 459, separated by a small gap. By positioning the flange portion 472 between the annular surface 458 and the counter plate 457, axial movement of the flange portion 472 and the shaft 470 is prevented.

[0117] Lubricating oil is filled between the shaft 470 and the bearing sleeve 450. Specifically, the lubricating oil is filled between the outer circumferential surface of the shaft portion 471 and the inner circumferential surface 450a of the bearing sleeve 450, between the upper surface of the flange portion 472 and the annular surface 458, between the lower surface of the flange portion 472 and the upper surface of the counter plate 457, and between the side surface of the flange portion 472 and the inner circumferential surface 459.

[0118] The rotor hub 480 is a component that rotates together with the shaft 470. The rotor hub 480 is attached to the upper end of the shaft 470 and connected to the shaft 470. The rotor hub 480 has a disc portion 481, a first cylindrical portion 482, a second cylindrical portion 483, and an outer edge portion 484.

[0119] The disc portion 481 is a disc-shaped member that is coaxial with the central axis of the shaft 470 in an axial view. The disc portion 481 has a rotor hub through hole 485. The rotor hub through hole 485 is located at the center of the disc portion 481 in an axial view. The disc portion 481 is fixed to the shaft 470. Specifically, the upper end of the shaft 70 is inserted into the rotor hub through hole 485 and the disc portion 481 is fixed to the shaft 470 by a method such as press-fitting or adhesive. When the shaft 470 is supported by the bearing sleeve 450, the disc portion 481 faces the end face 454 of the bearing sleeve 450 with a small gap between them.

[0120] The first cylindrical portion 482 is a cylindrical member having thickness in the radial direction. The first cylindrical portion 482 is provided so as to be coaxial with the central axis of the rotor hub through hole 485 in an axial view, and protrudes downward in the axial direction from the lower surface of the disc portion 481. The inner diameter of the first cylindrical portion 482 is larger than the outer diameter of the bearing sleeve 450. The inner circumferential surface of the first cylindrical portion 482 faces the outer circumferential surface of the bearing sleeve 450 with a gap between them. The outer diameter of the first cylindrical portion 482 is smaller than the inner diameter of the circumferential wall portion 413. The outer circumferential surface of the first cylindrical portion 482 faces the inner circumferential surface of the circumferential wall portion 413 with a gap between them.

[0121] The second cylindrical portion 483 is a cylindrical member having thickness in the radial direction. The second cylindrical portion 483 is provided so as to be coaxial with the central axis of the rotor hub through hole 485 in an axial view, and protrudes downward in the axial direction from the lower surface of the disc portion 481. The second cylindrical portion 483 is provided on the outer edge of the disc portion 481.

[0122] The outer edge portion 484 is an annular member. The outer edge portion 484 is provided at the lower end of the second cylindrical portion 483. The outer edge portion 484 protrudes radially outward from the second cylindrical portion 483 and is formed in a flange shape. Multiple blades 500 are provided above the outer edge portion 484 and radially outward from the second cylindrical portion 483, spaced apart in the circumferential direction.

[0123] Lubricating oil is filled between the rotor hub 480 and the bearing sleeve 450. Specifically, the lubricating oil is filled between the lower surface of the disc portion 481 located axially inward from the first cylindrical portion 482 and the end face 454 of the axially upper sleeve end portion 453a of the bearing sleeve 450.

[0124] The rotor magnet 490 is an annular member having a magnetic pole structure in which the polarity reverses along the circumferential direction in an axial view, in the order N, S, N, S… In this embodiment, the rotor magnet 490 is attached to the inner circumferential surface of the second cylindrical portion 483.

[0125] In this embodiment, the conductive member 300 is attached with a conductive adhesive or the like so that the upper surface of the mounting portion 301 is in contact with the lower surface of the first cylindrical portion 482, as shown in Figure 15(a). The outer diameter of the mounting portion 301 is approximately equal to the outer diameter of the first cylindrical portion 482. One deformable portion 302 is provided so as to extend downward from the outer edge of the mounting portion 301.

[0126] <Spindle motor operation> When current is applied to the coil 461, the magnetic attraction and repulsion forces between the magnetic poles of the rotor magnet 490 and the pole teeth of the stator core 460 switch. As a result, the rotating part 440 rotates relative to the stationary part 430 with the shaft 470 as its axis of rotation.

[0127] The shaft 470 rotates relative to the bearing sleeve 450. During this rotation, the lubricating oil is pressurized by the radial dynamic pressure generating groove 451, generating dynamic pressure in the lubricating oil. This generated dynamic pressure supports the shaft 470 radially relative to the bearing sleeve 450 in a non-contact manner.

[0128] As the shaft 470 rotates, the rotor hub 480 rotates relative to the bearing sleeve 450. At this time, the lubricating oil is pressurized by the thrust dynamic pressure generating groove 452, generating dynamic pressure in the lubricating oil. Due to the generated dynamic pressure, the rotor hub 480 is supported axially in a non-contact manner relative to the bearing sleeve 450.

[0129] When the spindle motor 403 rotates, the multiple blades 500 also rotate. The rotation of the multiple blades 500 creates an axial flow of air (a flow from top to bottom or bottom to top in Figure 14).

[0130] When the rotating part 440 rotates, a radial centrifugal force acts on the conductive member 300, intersecting the axial direction in which the deformable part 302 extends. As a result, the deformable part 302 deforms in a direction intersecting the axial direction. Specifically, as shown in Figure 15(b), the deformable part 302 of the conductive member 300 attached to the first cylindrical part 482 deforms in a direction intersecting the axial direction and comes into contact with the circumferential wall part 413 of the base plate 410.

[0131] Furthermore, when the rotation of multiple vanes 500 generates an airflow from bottom to top as shown in Figure 14, an airflow from bottom to top is generated in the gap between the first cylindrical portion 482 and the circumferential wall portion 413 in Figure 15(a). Consequently, an airflow from the radially inner to the outer direction is generated in the gap continuous with this gap, where the lower surface of the first cylindrical portion 482 and the base plate 410 face each other. This airflow also collides with the deformable portion 302, causing the deformable portion 302 to deform in a direction intersecting the axial direction.

[0132] When the rotating part 440 rotates, it may become charged. As a result, unintended discharge may occur from the rotating part 440 toward nearby components, potentially damaging them. In this embodiment, the spindle motor 403 deforms as the rotating part 440 rotates, causing it to contact both the rotating part 440 (the first cylindrical part 482 of the rotor hub 480) and the stationary part 430 (the circumferential wall part 413 of the base plate 410). Therefore, the charge accumulated in the rotating part 440 flows through the conductive member 300 to the stationary part 430. Consequently, unintended discharge from the rotating part 440 toward nearby components is less likely to occur.

[0133] =Fourth Embodiment= Next, the motor 600 of the fourth embodiment will be described. The motor 600 is, for example, a drive motor for an electric vehicle. As shown in Figure 16, the motor 600 comprises a casing 610, a bearing 620, a shaft 630, a magnet 640, a stator core 650, a conductive member 300, and a conductive member 660.

[0134] The casing 610 is a housing that contains the components of the motor 600. The casing 610 is constructed by combining the case 611 and the lid 612.

[0135] The case 611 is a cylindrical member with one opening closed. The case 611 has a bearing mounting portion 613 and a stator core mounting portion 614. The bearing mounting portion 613 is provided on the closed surface of the case 611. The bearing mounting portion 613 is an annular wall provided so as to be coaxial with the central axis of the case 611 in an axial view, and protrudes upward in the axial direction. The inner diameter of the bearing mounting portion 613 is approximately equal to the outer diameter of the bearing 620. The stator core mounting portion 614 is provided so as to protrude inward from the side wall portion of the case 611. The stator core mounting portion 614 is provided along the side wall portion of the case 611 in the circumferential direction over its entire circumference.

[0136] The lid 612 is a disc-shaped member that closes the opening of the case 611. The lid 612 is attached to the opening of the case 611 so as to be coaxial with the case 611. As shown in Figures 16 and 18, the lid 612 has a through hole 615, a bearing mounting portion 616, and a thrust dynamic pressure generating groove 617. The through hole 615 is a hole provided so as to be coaxial with the central axis of the lid 612 and penetrates the lid 612 in the axial direction. The bearing mounting portion 616 is an annular wall provided so as to be coaxial with the central axis of the lid 612 in an axial view and protrudes downward from the lower surface of the lid 612 (the surface facing the case 611). The inner diameter of the bearing mounting portion 616 is approximately equal to the outer diameter of the bearing 620. The thrust dynamic pressure generating groove 617 is provided on the upper surface of the lid 612 and near the through hole 615. The thrust dynamic pressure generating groove 617 is provided in an annular shape so as to be coaxial with the central axis of the cover 612 when viewed in the axial direction.

[0137] The bearing 620 is a component that rotatably supports the shaft 630. The bearing 620 is a rolling bearing such as a ball bearing or a roller bearing. The inner diameter of the bearing 620 is approximately equal to the outer diameter of the shaft 630. The bearing 620 is fixed to the bearing mounting portion 613 and the bearing mounting portion 616 by methods such as press-fitting and adhesive bonding.

[0138] The shaft 630 is the rotating axis component of the motor 600. The shaft 630 is rotatably supported by two bearings 620. The shaft 630 has a columnar shaft portion 631 and a flange portion 632.

[0139] The shaft portion 631 is a cylindrical shaft member. The shaft portion 631 is tapered at both its upper and lower ends 633 compared to its central portion. The outer diameter of the ends 633 is approximately equal to the inner diameter of the bearing 620. The shaft 630 is supported by the bearings 620 by press-fitting the upper and lower ends 633 into the two bearings 620 fixed to the bearing mounting portions 613 and 616, respectively.

[0140] The flange portion 632 is an annular flange member that expands radially in an axial view. The flange portion 632 is provided on the upper end 633 of the shaft portion 631. When the motor 600 is assembled, the flange portion 632 is positioned above the cover 612. The lower surface of the flange portion 632 faces the upper surface of the cover 612 with a small gap between them.

[0141] The flange portion 632 may also be an impeller attached to the shaft 630.

[0142] The magnet 640 is an annular member having a magnetic pole structure in which the polarity reverses along the circumferential direction in an axial view, in the order N, S, N, S… In this embodiment, the magnet 640 is mounted between the upper and lower ends 633 in the axial direction of the shaft portion 631.

[0143] The stator core 650 is a component formed by stacking multiple annular electromagnetic steel sheets in the axial direction when viewed axially. The stator core 650 is placed on the stator core mounting portion 614 and fixed by adhesive or other methods. When the motor 600 is assembled, the stator core 650 faces the magnet 640 in the radial direction. The stator core 650 has pole teeth (salient poles) that extend radially inward and are arranged in multiple locations along the circumferential direction. Coils 651 are wound around the pole teeth. The stator core 650 generates magnetic flux when current flows through the coils 651.

[0144] In this embodiment, the conductive member 300 is attached with a conductive adhesive or the like so that the upper surface of the mounting portion 301 contacts the lower end surface of the shaft 630, as shown in Figure 17(a). The outer diameter of the mounting portion 301 is approximately equal to the outer diameter of the end portion 633 of the shaft 630. One deformable portion 302 is provided so as to extend downward from the outer edge of the mounting portion 301.

[0145] The conductive member 660 makes two members electrically connected by contacting them. The conductive member 660 is formed of a conductive material, or is configured such that a conductive path is formed between the parts that contact the two members. The conductive member 660 is a material that easily conducts electricity, such as metals such as brass, aluminum, and stainless steel, or polymer compounds such as polyacetylene and polythiophene. Unlike the conductive members 130 and 300 described in the above embodiment, the conductive member 660 is a plate-shaped member. The conductive member 660 has a mounting portion 661 and a deformable portion 662.

[0146] The mounting portion 661 is a part that is attached to another member. The mounting portion 661 is a rectangular plate-shaped member. The upper or lower surface of the mounting portion 661 is fixed to the member to which the mounting portion 661 is to be fixed by a method such as bonding with a conductive adhesive.

[0147] The deformable portion 662 is a member that deforms when subjected to force and comes into contact with another member. The deformable portion 662 extends in the same plane from the end of the mounting portion 661.

[0148] In this embodiment, the conductive member 660 is a rectangular member in plan view. As shown in Figure 18(a), the conductive member 660 is attached with a conductive adhesive or the like so that the lower surface of the mounting portion 661 is in contact with the upper surface of the lid 612. In this case, the mounting portion 661 extends radially inward. The deformable portion 662 is provided so as to extend further radially inward from the radially inward end of the mounting portion 661.

[0149] <Motor operation> When current is applied to the coil 651, the magnetic attraction and repulsion forces between the magnetic poles of the magnet 640 and the pole teeth of the stator core 650 switch. As a result, the shaft 630 rotates.

[0150] As the shaft 630 rotates, the flange portion 632 rotates relative to the lid 612. At this time, the air between the flange portion 632 and the lid 612 is pressurized by the thrust dynamic pressure generating groove 617, generating dynamic pressure in the air. Due to the dynamic pressure generated by the thrust dynamic pressure generating groove 617, the air between the flange portion 632 and the lid 612 flows from the radially inner side to the radially outer side.

[0151] Furthermore, if the flange portion 632 is an impeller, when the shaft 630 rotates, an axial airflow (from bottom to top) is generated in the air between the shaft 630 and the cover 612.

[0152] When the shaft 630 rotates, a radial centrifugal force acts on the conductive member 300, intersecting the axial direction in which the deformable portion 302 extends. As a result, the deformable portion 302 deforms in a direction intersecting the axial direction. Specifically, as shown in Figure 17(b), the deformable portion 302 of the conductive member 300 attached to the shaft 630 deforms in a direction intersecting the axial direction and comes into contact with the case 611.

[0153] Furthermore, when the shaft 630 rotates, a force generated by the airflow acts on the conductive member 660. Specifically, as shown in Figure 18(b), the air between the flange portion 632 and the lid 612 flows from the radially inward to the outward. Then, the air in the gap between the shaft 630 and the lid 612, which is connected to the flange portion 632 and the lid 612, flows from bottom to top (i.e., axially). The air flowing axially, which is perpendicular to the radial direction in which the deformable portion 662 extends, collides with the lower surface of the deformable portion 662, causing the deformable portion 662 to deform in a direction perpendicular to the radial direction. Also, if the flange portion 632 is an impeller, the air flowing from bottom to top collides with the lower surface of the deformable portion 662, causing the deformable portion 662 to deform in a direction perpendicular to the radial direction. Note that the direction perpendicular to a certain direction (for example, the radial direction) does not need to be parallel to the direction in which the deformable portion 662 extends (the radial direction in this embodiment).

[0154] When the shaft 630 rotates, the shaft 630 and the bearing 620 may become charged. As a result, unintended discharge may occur from the shaft 630 toward a nearby component, or from the rolling elements of the bearing 620 toward the stationary part, potentially damaging the component. In this embodiment, the motor 600 deforms as the shaft 630 rotates, causing the conductive member 300 to contact both the shaft 630 and the case 611. Also, as the shaft 630 rotates, the conductive member 660 deforms, causing it to contact both the flange portion 632 and the cover 612. Therefore, the charge accumulated on the shaft 630 and the bearing 620 flows through the conductive members 300 and 660 to the case 611 and cover 612. Consequently, unintended discharge from the shaft 630 toward a nearby component is less likely to occur. Similarly, unintended discharge from the rolling elements of the bearing 620 toward the stationary part is less likely to occur.

[0155] <Variation> Furthermore, the spindle motors 3, 203, 403 and motor 600 may be used in appropriate combinations of the aforementioned conductive members 130, 300, and 660. In addition, the conductive members 130, 300, and 660 may be combinations of the modifications described below.

[0156] (1) Variation 1 The mounting portion 131 and the deformable portion 132 may be composed of a conductive member having electrical conductivity and a protective material to protect the conductive member. For example, the mounting portion 131 and the deformable portion 132 may have a structure in which the conductive member is covered with a protective material, except for the parts that come into contact with other members. The conductive members of the mounting portion 131 and the deformable portion 132 are configured to be connected to each other.

[0157] (2) Modification example 2 The mounting portion 131 and the deformable portion 132 only need to have a conductive member provided on at least a part of their surface. For example, the mounting portion 131 and the deformable portion 132 may be a plate-shaped base material with a plate-shaped conductive member attached, or a plate-shaped base material with a linear conductive member attached. The conductive members of the mounting portion 131 and the deformable portion 132 are configured to be connected to each other.

[0158] (3) Modification example 3 The conductive member provided in the deformable portion 132 may have an abrasion-resistant coating formed on the part that comes into contact with other members when deformed. The abrasion-resistant coating may be made of DLC (Diamond-Like Carbon), for example.

[0159] <Effects> (Aspect 1) In this embodiment, the spindle motor 3 comprises a conductive member 130 that deforms when subjected to force, an end cap 100 to which the conductive member 130 is attached, and an upper conical bearing member 72 that contacts the conductive member 130 in a deformed state. The conductive member 130 has a mounting portion 131 attached to the end cap 100, and a deformable portion 132 extending from the mounting portion 131 that deforms when subjected to force and contacts the upper conical bearing member 72. The deformable portion 132 extends axially when not subjected to force, and deforms radially intersecting the axial direction when subjected to force, generating force by causing at least one of the end cap 100 and the upper conical bearing member 72 to rotate.

[0160] According to the spindle motor 3 described above, centrifugal force is generated when the rotating part 40 rotates, and the deformable part 132 extending in the axial direction is deformed in the radial direction intersecting the axial direction by the centrifugal force. As a result, the conductive member 130 comes into contact with both the end cap 100 (first member) and the upper conical bearing member 72 (second member). Therefore, current flows through the end cap 100 and the upper conical bearing member 72 via the conductive member 130. Here, the end cap 100 is a member of the rotating part 40, and the upper conical bearing member 72 is a member of the stationary part 30. In other words, it is possible to provide a motor having a structure that makes the rotating part 40 and the stationary part 30 electrically connected.

[0161] Furthermore, because the rotating part 40 and the stationary part 30 of the spindle motor 3 are electrically connected, unintended discharge phenomena are less likely to occur. As a result, the lifespan of the spindle motor 3 is extended.

[0162] Furthermore, since the deformable portion 132 of the conductive member 130 deforms in a direction intersecting the direction in which the deformable portion 132 extends, even if the two members, such as the end cap 100 and the upper conical bearing member 72, are not arranged on the same plane, the conductive member 130 attached to the end cap 100 can deform and come into contact with the upper conical bearing member 72. Therefore, there is a high degree of freedom in the placement position of the conductive member 130.

[0163] (Aspect 2) In aspect 1, the direction in which the deformable portion 132 extends when no force is applied is one of the following: the axial direction parallel to the rotation axis of the spindle motor 3, the radial direction perpendicular to the axial direction, or the circumferential direction perpendicular to both the axial and radial directions.

[0164] In the spindle motor 3 described above, the deformable portion 132 extends in one of the axial, radial, or circumferential directions. Since many of the components of the spindle motor 3 are parallel to the axial, radial, and circumferential directions, the conductive member 130 is easy to attach to the components of the spindle motor 3.

[0165] (Aspect 3) In aspect 1 or 2, the mounting portion 131 and the deformed portion 132 each have a conductive member having electrical conductivity and a protective material covering the conductive member.

[0166] With the spindle motor 3 described above, the mounting portion 131 and the deformation portion 132 are made of conductive material, and since the conductive material is covered with a protective material, it is possible to prevent the conductive material from coming into contact with an unintended area and causing current to flow.

[0167] (Aspect 4) In aspect 1 or 2, the mounting portion 131 and the deformed portion 132 are provided with a conductive member having conductivity on at least a portion of their surface.

[0168] With the spindle motor 3 described above, by providing a conductive member on a part of the surface of the mounting portion 131 and the deformable portion 132, it is possible to prevent the conductive member from coming into contact with an unintended area and causing current to flow.

[0169] (Aspect 5) In aspect 4, the conductive member provided on the deformed portion 132 has a wear-resistant conductive film formed on the portion that comes into contact with the upper conical bearing member 72.

[0170] In the spindle motor 3 described above, a conductive, wear-resistant film is formed on the portion of the conductive member that comes into contact with the upper conical bearing member 72, making that portion less susceptible to wear. Therefore, the function of the conductive member is less likely to be impaired by wear.

[0171] (Aspect 6) In any of aspects 1 to 5, the mounting portion 131 is annular.

[0172] With the spindle motor 3 described above, since the mounting portion 131 is annular, it is easy to attach the conductive member 130 to two opposing members along a gap that extends in the circumferential direction.

[0173] (Aspect 7) In any of aspects 1 to 5, the mounting portion 131 is rod-shaped or plate-shaped.

[0174] With the spindle motor 3 described above, the mounting portion 131 is rod-shaped or plate-shaped, making it easy to manufacture the conductive member 130.

[0175] (Aspect 8) In any of aspects 1 to 6, the deformed portion 132 has a slit 135.

[0176] With the spindle motor 3 described above, since the deformable portion 132 has a slit 135, the deformable portion 132 can be made into a substantially annular shape divided by the slit 135 in an axial view. Therefore, the deformable portion 132 can be made large in the circumferential direction of the end cap 100, and the conductive member 130 can easily come into contact with the upper conical bearing member 72.

[0177] (Aspect 9) In aspect 8, the length of the end of the upper conical bearing member 72 of the slit 135 is shorter than the length of the end on the end cap 100 side.

[0178] According to the spindle motor 3 described above, the shape of the slit 135 such that the length of the end on the upper conical bearing member 72 side is shorter than the length of the end on the end cap 100 side, means that when the deformed portion 132 extends downward from the end cap 100, the end on the upper conical bearing member 72 side becomes heavier. When the spindle motor 3 rotates, a greater centrifugal force is applied to the end of the deformed portion 132 on the upper conical bearing member 72 side, making the deformed portion 132 more prone to deformation. In other words, the deformed portion 132 is more likely to come into contact with the upper conical bearing member 72.

[0179] (Aspect 10) In any of aspects 1 to 9, the force is generated by the flow of the fluid.

[0180] With the spindle motor 3 described above, the force that deforms the deformable part 132 is generated by the flow of a fluid such as air. Therefore, by configuring the spindle motor 3 to generate the fluid flow through its rotation, the deformable part 132 can be deformed without adding any other power source.

[0181] (Aspect 11) In aspect 10, the fluid flow is generated by an impeller provided on at least one of the first member and the second member.

[0182] According to the spindle motor 403 described above, fluid flow is generated by providing an impeller on at least one of the first member and the second member. In the spindle motor 403, a plurality of blades 500 are provided on the rotor hub 480, which is the rotating part 440. Since one of the first member and the second member is a rotating body, the rotation of the spindle motor 403 can generate a force that deforms the deformable part 302.

[0183] (Aspect 12) In aspect 10, the fluid flow is generated by a fluid dynamic pressure groove provided in at least one of the first member and the second member.

[0184] With the motor 600 described above, fluid flow is generated by providing a fluid dynamic pressure groove in at least one of the first member and the second member. In the motor 600, a thrust dynamic pressure generating groove 617 is provided in the cover 612. Since one of the first member and the second member is a rotating body, the rotation of the motor can generate a force that deforms the deformable part 662.

[0185] (Aspect 13) In any of aspects 1 to 12, the force is generated by centrifugal force.

[0186] With the spindle motor 3 described above, the force that deforms the deformable part 132 is generated by centrifugal force. Therefore, by configuring the motor so that centrifugal force is applied to the deformable part 132 by the rotation of the motor, the deformable part 132 can be deformed without adding any other power source.

[0187] (Aspect 14) In aspect 13, the deformed portion 132 is heavier on the side that contacts the upper conical bearing member 72 than on the end cap 100 side.

[0188] With the spindle motor 3 described above, the deformable portion 132 is configured such that the side in contact with the upper conical bearing member 72 is heavier than the side with the end cap 100, thereby applying a large centrifugal force to the side in contact with the upper conical bearing member 72. As a result, the deformable portion 132 becomes more easily deformed and more likely to come into contact with the upper conical bearing member 72. In particular, by providing a weight portion 136 on the side of the deformable portion 132 that is in contact with the upper conical bearing member 72, the deformable portion 132 becomes even more easily deformed and more likely to come into contact with the upper conical bearing member 72.

[0189] (Aspect 15) The hard disk drive unit 1 is equipped with a spindle motor 3 according to any of aspects 1 to 14.

[0190] The hard disk drive 1 described above is equipped with a spindle motor 3 that is less prone to unintended discharge phenomena. Since the lifespan of this spindle motor 3 is extended compared to conventional products, the lifespan of the hard disk drive 1 is similarly extended. [Explanation of symbols]

[0191] 1…Hard disk drive unit (rotational drive unit), 3, 203, 403…Spindle motor, 10…Base plate (second member), 72…Upper conical bearing member (second member), 84…Outer edge (first member), 100…End cap (first member), 130, 300, 660…Conductive member, 131, 301, 661…Mounting part, 132, 302, 662…Deformed part, 135…Slit, 213, 413…Circumferential wall part (second member), 286…Enlarged diameter part (first member), 482…First cylindrical part (first member), 611…Case (second member), 612…Lid (second member), 617…Thrust dynamic pressure generating groove (fluid dynamic pressure groove), 630…Shaft (first member), 632…Flange part (first member)

Claims

1. A conductive member that deforms when subjected to force, The first member to which the conductive member is attached, The conductive member contacts a second member in a deformed state, Equipped with, The conductive member has a mounting portion attached to the first member and a deformable portion extending from the mounting portion, which deforms upon receiving the force and contacts the second member. The deformable portion extends in a first direction when not subjected to the force, and deforms in a second direction intersecting the first direction when subjected to the force. The force is generated by the rotation of at least one of the first member and the second member. Motor.

2. The motor according to claim 1, wherein the first direction is any of the axial direction parallel to the rotation axis of the motor, the radial direction perpendicular to the axial direction, or the circumferential direction perpendicular to the axial direction and the radial direction.

3. The motor according to claim 1, wherein the mounting portion and the deformation portion each have a conductive member having electrical conductivity and a protective material covering the conductive member.

4. The motor according to claim 1, wherein the mounting portion and the deformation portion are provided with a conductive member having conductivity on at least a portion of their surface.

5. The motor according to claim 4, wherein the conductive member provided in the deformed portion has a conductive, wear-resistant film formed on the portion that contacts the second member.

6. The motor according to claim 1, wherein the mounting portion is annular.

7. The motor according to claim 1, wherein the mounting portion is rod-shaped or plate-shaped.

8. The motor according to claim 1, wherein the deformed portion has a slit.

9. The motor according to claim 8, wherein the length of the end of the slit on the second member side is shorter than the length of the end of the slit on the first member side.

10. The motor according to claim 1, wherein the force is generated by the flow of a fluid.

11. The motor according to claim 10, wherein the fluid flow is generated by an impeller provided on at least one of the first member and the second member.

12. The motor according to claim 10, wherein the fluid flow is generated by a fluid dynamic pressure groove provided in at least one of the first member and the second member.

13. The motor according to claim 1, wherein the force is generated by centrifugal force.

14. The motor according to claim 13, wherein the deformed portion is heavier on the side that contacts the second member than on the side that contacts the first member.

15. A rotary drive device comprising a motor according to any one of claims 1 to 14.

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