JP5060902B2 - Hard disk drive motor - Google Patents

Description

The present invention relates to a motor for a hard disk drive, in particular motor for a hard disk drive including a flexible wiring board for supplying a driving current from the outside through the base frame to the stator coils, the flexible printed circuit board The present invention relates to a hard disk drive motor that can prevent dust from entering a hard disk drive from a portion penetrating a base frame.

  In general, a motor used as a drive source for precision equipment uses a flexible printed circuit (FPC) that does not require a large wiring area as a means for supplying a drive current to the stator coil from the outside. This is pulled out from the slit-shaped through hole formed in the base frame to the outside of the motor. However, if the flexible wiring board is only passed through the base frame, dust will enter the motor through the through hole. The rotational performance of the motor is impaired, and there is a possibility that the information recording / reproducing may be hindered in the hard disk drive (HDD).

  For this reason, the through hole is closed with an adhesive so that dust does not enter from the through hole through the flexible wiring board (for example, Patent Document 1).

  In particular, at the position of the through hole through which the flexible wiring board is passed, a seal is attached from the inside of the base frame to close the through hole, and then an ultraviolet curable resin is injected into the through hole from the outside of the base frame. Curing is performed (for example, Patent Document 2).

  In addition, in a lens barrel of a single-lens reflex camera in which a motor is incorporated, a flexible wiring board is assigned to a through hole formed in a housing so as to be loaded with a motor, thereby closing the through hole ( For example, Patent Document 3).

Japanese Patent Laid-Open No. 2002-300746 (paragraph 0021, FIG. 1)

JP-A-11-299168 (paragraph 0028, FIGS. 1 to 7) JP-A-1-235909 (pages 2 and 3, FIGS. 1 to 3)

  However, according to Patent Document 1, the flexible wiring board C passed through the through hole H as shown in FIG. 13 bends to the state of being lifted from the base frame F outside the motor. Even if A is injected, the through hole H remains open at the bent portion Df of the flexible wiring board C. In particular, as shown in FIG. 14 (when FIG. 13 is viewed from below), when the width of the flexible wiring board C is substantially the same as the longitudinal length of the through-hole H, the adhesive A injected into the through-hole H is added to the flexible wiring board. Since it cannot wrap around the bending part Df of C satisfactorily, dust enters the motor from that part (see the arrow shown in FIG. 13).

  Further, as shown in FIG. 15 (when FIG. 13 is viewed from below), when the width of the flexible wiring board C is reduced with respect to the through hole H, the adhesive injected into the through hole H is deflected by the flexible wiring board C. Even though the adhesive can wrap around Df, most of the adhesive flows into the motor through the gap between the flexible wiring board C and the through hole H, so it becomes difficult to seal the through hole H. There is a possibility that the adhesive that has flowed into the motor adheres to the drive unit and interferes with motor performance.

  On the other hand, in Patent Document 2, since the seal is used together, it is possible to prevent the adhesive from flowing into the motor from the through hole. However, it is difficult to apply the seal in accordance with the position of the through hole. Since the number of man-hours and the number of parts increase, there is a problem that the productivity of the motor deteriorates and the cost increases.

  In addition, as described in Patent Document 3, if the flexible wiring board is only assigned to the through hole, the sealing of the through hole becomes uncertain, and it is applicable to a motor having a structure in which the flexible wiring board is drawn out from the through hole. Can not.

The present invention has been made in view of the circumstances as described above, and an object of the present invention is to prevent the intrusion of dust from the through hole through the flexible wiring board into the hard disk drive device formed by the motor. The object is to provide a motor for a hard disk drive .

One embodiment of the present invention relates to a motor for a hard disk drive. The hard disk drive motor includes a base frame to which a stator core is fixed, a base frame that is rotatably disposed, a field magnet that is radially opposed to the stator core, and a rotor hub that supports the hard disk, and a stator core. A stator coil formed by winding a conductor wire and a thin plate-like flexible wiring board for energizing the stator coil are provided. The flexible wiring board is formed in the base frame and the inner wiring portion disposed on the inner bottom surface side, which is the side on which the hard disk of the base frame is supported, having a land portion that conductively connects the end portions of the conductor wires. A lead-out wiring portion drawn from the inner bottom surface side to the outer bottom surface side opposite to the inner bottom surface through the elongated hole-shaped through hole, and the width of the lead-out wiring portion is smaller than the longitudinal length of the through-hole, The lead-out wiring part and the inner wiring part are connected via a wide sealing part larger than the width of the lead-out wiring part, and the wide sealing part is arranged at a position closing the through hole, and a sealing material is injected into the through hole. The sealing material is characterized in that it extends between the base frame and the lead-out wiring part over the entire width of the lead-out wiring part.

  The motor according to the present invention includes a flexible wiring board for energizing the stator coil, and has an inner wiring portion and a lead wiring portion that is continuously drawn out from the through hole to the inner wiring portion, Since the width of the lead-out wiring portion is made smaller than the longitudinal length of the through hole, the operation of passing through the through hole can be easily performed.

  In addition, the lead-out wiring part and the inner wiring part are connected via a wide sealing part larger than the width of the lead-out wiring part, and the wide sealing part is arranged at a position closing the through hole. When injected into the sealant, it is possible to prevent the sealing material from leaking from the through hole and adhering to an unintended portion.

  In particular, at the boundary portion between the lead-out wiring part and the wide sealing part, the sealing material goes well between the base frame forming the through hole and the lead-out wiring part, and this extends along the width direction of the lead-out wiring part. As a result, the through hole can be securely closed and dust can be prevented from entering the motor from the outside, and the wide sealing part is fixed to the base frame with a sealing material at the position where the through hole is blocked, and the lead-out wiring The part is also fixed to the base frame by the sealing material that wraps around the base frame at the boundary with the wide sealing part, so that the adhesive strength of the flexible wiring board by the sealing material is increased and the peeling is prevented, so the dust-proof effect Can be maintained over a long period of time.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In the following description, an HDD motor that rotationally drives a hard disk will be described as a representative example, but the present invention can also be applied to a disk driving motor that rotationally drives other disks, a scanning motor that rotationally drives a polygon mirror, and the like. .

  FIG. 1 is a longitudinal sectional view showing a configuration example of a motor according to the present invention. The motor constitutes a hard disk drive (HDD), and the form thereof is an outer rotor type in which a rotor 2 (rotor) is provided on the outer periphery of a stator 1 (stator).

  In this example, the stator 1 includes a base frame 11 having a cylindrical portion 11a in the center portion, a cylindrical bearing 12 fitted into the cylindrical portion 11a, and the like. The base frame 11 is formed by cutting a casting (aluminum die casting or the like) or pressing a metal plate (aluminum plate or iron plate with nickel plating) or the like. A stator core 13 made of a laminate of silicon steel plates or the like is fitted and fixed to the outer periphery.

  The stator core 13 has a plurality of magnetic pole teeth 13a (tooth-like protrusions) that spread radially, and a conductor wire (coil winding) such as a copper wire coated with an insulating film is wound around each magnetic pole tooth 13a. A stator coil 14 is formed. A driving current (armature current) is allowed to flow through the stator coil 14 through a flexible wiring board 3 (FPC) described later.

  The bearing 12 is a radial dynamic pressure bearing formed of copper-based sintered metal, stainless steel (SUS), or the like, and one end thereof is sealed with a seal plate 15. In particular, the bearing 12 is fixed in the cylindrical portion 11a of the base frame by press-fitting or adhesive in order to obtain high assembly accuracy. A rotor shaft 21 made of stainless steel or the like is inserted into the bearing 12, and the rotor shaft 21 is rotatably supported via lubricating oil filled in the bearing 12.

  As shown in FIG. 1, a flange portion 21a sandwiched between the bearing 12 and the seal plate 15 is formed on the outer periphery of one end of the rotor shaft 21, and the bearing 12 and the seal facing the flange portion 21a or both upper and lower surfaces of the flange portion 21a. A dynamic pressure generating groove (not shown) is formed in a portion of the plate 15 so that a thrust load acting on the rotor shaft 21 is supported by pressurization of lubricating oil.

  Further, as shown in FIG. 1, a herringbone-shaped dynamic pressure generating groove 21b is also formed on the outer peripheral portion of the rotor shaft 21, so that the radial load acting on the rotor shaft 21 is supported by the pressurization of the lubricating oil. However, such a groove may be formed on the inner peripheral surface of the bearing 12 or may be formed on both the bearing 12 and the rotor shaft 21. The bearing 12 is not limited to the dynamic pressure type, and can be replaced with other sliding bearings or rolling bearings.

  On the other hand, the rotor 2 includes the rotor shaft 21 and the rotor hub 22 fixed to the rotor shaft 21. The rotor hub 22 is a member having a concave cross section formed of stainless steel or the like, and its center is fixed to the tip of the rotor shaft 21 protruding from the bearing 12. In particular, a flange 22a is formed on the outer periphery of the rotor hub 22, and the disk D (hard disk in this example) is supported by the flange 22a. Further, on the inner peripheral surface of the rotor hub 22, a field magnet that generates a magnetic flux (field magnetic flux) necessary for generating a rotational force in the vicinity of the tip surface (a salient pole) of each magnetic pole tooth portion 13 a of the stator core 13. 23 is attached. The field magnet 23 is a ring-shaped permanent magnet (for example, Nd—Fe—B system) in which N poles and S poles are alternately magnetized in the circumferential direction, and nickel plating is applied to the surface thereof. .

  According to the motor configured as described above, a driving current is passed through the stator coil 14 to generate a rotating magnetic field, and the magnetic flux of the field magnet 23 acts on this to rotate the rotor hub 22.

  FIG. 2 is a partially enlarged view of the motor. As is apparent from this figure, the base frame 11 is formed with a through hole 11b that communicates with the motor interior (the part inside the rotor hub 22 where the stator coil 14 and the like are located), and the flexible wiring is formed through the through hole 11b. The plate 3 is drawn from the inner bottom surface 11c side of the base frame 11 to the outer bottom surface 11d side opposite to the inner bottom surface.

  Further, a concave portion 11e is formed on the outer bottom surface 11d of the base frame 11 so that the flexible wiring board 3 drawn out from the through hole 11b can be put. The recess 11e is covered with a dustproof plate 16 fixed to the base frame 11. However, since one end of the recess 11e is open to the outside, the through-hole is formed from one end of the recess 11e unless the through-hole 11b is closed. Dust enters the motor through 11b. For this reason, a liquid adhesive 4 (viscosity is 5000 mPa · s or more) made of an ultraviolet curable resin or the like as a sealing material is injected into the through-hole 11b, and the through-hole 11b is blocked by the hardening.

  FIG. 3 is a bottom view of the through-hole portion as seen from the outside, and the hatched portion in FIG. 3 represents the application region of the adhesive 4. As is apparent from FIG. 3, the through hole 11b is a long hole extending in a direction perpendicular to the drawing direction of the flexible wiring board 3 (radial direction of the base frame 11) (its longitudinal length L is the flexible wiring board). In this example, the longitudinal length L is 6.7 mm, and the gap dimension S is 1.0 mm.

  Next, FIG. 4 shows a flexible wiring board. As is apparent from this figure, the flexible wiring board 3 is formed of a resin sheet or the like with the insulating base 3a as a support, and a plurality of conductor patterns 3b (four in this example) made of copper foil or the like formed thereon. In the thin plate form, one side is an arc-shaped inner wiring portion 31, and a strip-shaped lead wiring portion 32 is connected to one end side of the inner wiring portion 31.

  The inner wiring portion 31 is provided with a plurality of (four in this example) land portions 31a in which each one end of the conductor pattern 3b is individually conductively connected, and a conductor wire forming a stator coil in each land portion 31a. The end of (coil winding) is conductively connected. In this example, the stator coil 14 shown in FIG. 1 has three conductor wires wound around every nine magnetic pole tooth portions 13a in order to make a three-phase star connection. Each end of the conductor lines is separately conductively connected to the three land portions 31a, and each other end of the conductor wires is conductively connected to one land portion 31a remaining as a common terminal.

  In addition, a rectangular terminal portion 33 is continuously formed on one end side of the lead wiring portion 32, and the terminal portion 33 is connected to a drive circuit via a connector (not shown).

Here, the lead-out wiring portion 32 and the terminal portion 33 have widths W ₂ and W ₃ smaller than the longitudinal length L (see FIG. 3) of the through-hole so that they can be passed through the through-hole 11b (in this example). W ₂ is the 2.4 mm) is the, in the continuous portion of the inner lead portion 31 and the lead-out wiring portion 32, wide wide sealing portion 34 from the lead-out wiring portion 32 is formed. That is, the inner wiring portion 31 and the lead wiring portion 32 are connected via the wide sealing portion 34 that is larger than the width of the lead wiring portion 32. The wide sealing portion 34 is a protrusion of the wing projecting on both sides in the width direction of the lead wire sections 32, the width W ₁ is the same as or longitudinal length L of the through hole is slightly smaller than that ing.

  According to the flexible wiring board 3, the lead-out wiring portion 32 is passed through the through hole 11 b from the terminal portion 33 side, and the inner wiring portion 31 is adhered and fixed to the inner bottom surface 11 c of the base frame with a double-sided tape or the like. . In particular, the wide sealing portion 34 is disposed at a position to close the through hole 11b, and the wide sealing portion 34 closes the through hole 11b leaving a slight gap at the peripheral edge thereof.

  FIG. 5 is an enlarged view showing a portion of the through hole through which the flexible wiring board is passed. FIG. 6 shows the portion viewed from the outside (on the bottom surface 11d side of the base frame), and FIG. 7 shows the portion inside. The state seen from the inner bottom surface 11c side of the base frame is shown.

  As is apparent from FIG. 5, the wide sealing portion 34 is introduced into the through hole 11b on the lead wiring portion 32 side with the edge 34a on the inner wiring portion 31 side overlapping the inner bottom surface 11c of the base frame. In particular, according to this example, the wide sealing portion 34 has a gap p between the edge 34b and the through hole 11b, with the edge 34b on the lead-out wiring portion 32 side not overlapping the outer bottom surface 11d of the base frame. Is formed.

  Thus, when an adhesive is injected into the through-hole 11b from the outer bottom surface 11d side of the base frame 11, the wide sealing portion 34 serves as a support for the adhesive 4, and the adhesive 4 does not sag inside the motor. The wide sealing portion 34 is fixed to the base frame 11, and the adhesive 4 wraps between the base frame 11 and the lead wiring portion 32 from the gap p, whereby the lead wiring portion 32 is also wide sealing portion. 34 is fixed to the base frame 11 at the boundary portion. Therefore, the lead-out wiring part 32 does not float up and the bending part Df does not expand.

  In particular, the adhesive 4 that wraps around between the base frame 11 and the lead-out wiring portion 32 spreads well in the flexible portion Df of the flexible wiring board 3 as shown by the arrows in FIG. As shown in FIG. 7, since the adhesive 4 is continuous over the entire width of the lead-out wiring portion 32 and the through hole 11b is completely blocked, the intrusion of dust from the through hole 11b into the motor is prevented. Depending on the width of the lead-out wiring portion 32 and the viscosity of the adhesive 4, the adhesive 4 may not be continuous over the entire width of the lead-out wiring portion 32. Even if remains, the communication portion with the through hole 11b becomes extremely small, so there is almost no possibility of dust intrusion.

  Here, the wide sealing portion 34 is not limited to the end edge 34a on the inner wiring portion 31 side being overlapped with the base frame 11, but the end edge 34b on the lead wiring portion 32 side as shown in FIG. It may overlap with the outer bottom surface 11d. Even in this case, the adhesive 4 is driven between the base frame 11 and the lead-out wiring portion 32 from the boundary portion between the wide sealing portion 34 and the lead-out wiring portion 32 as shown in FIG. The through-hole 11b can be completely closed while the lead-out wiring portion 32 is fixed to the base frame 11 with the adhesive 4.

Next, FIG. 9 shows a modification of the wide sealing portion. 9, the wide sealing portion 34 is in the form of continuous without boundary and the inner lead portion 31, the width W ₁ is also greater than the extension wire 32 and the above example, with respect to the longitudinal length L of the through-hole 11b Same or slightly smaller. Further, this kind of wide sealing portion 34 is also introduced into the through hole 11b to support the adhesive 4, and at the boundary portion between the wide sealing portion 34 and the lead-out wiring portion 32, as shown in FIG. As in the case shown in FIG. 8, the adhesive 4 can be inserted between the base frame 11 and the lead-out wiring portion 32 to completely close the through-hole 11b.

The width W ₁ of the wide sealing portion 34 is the same as the longitudinal length L of the through-hole 11b, or not limited to it slightly is less than, than the longitudinal length L of the width W ₁ through hole 11b In this case, the wide sealing portion 34 is disposed at a position closing the through hole 11b, but is not introduced into the through hole 11b, and the inner bottom surface 11c side of the base frame 11 as shown in FIG. The lead wiring portion 32 is drawn out to the outer bottom surface 11d side of the base frame through the through hole 11b.

  In the embodiment shown in FIG. 10, the wide sealing portion 34 is fixed to the base frame 11 by the adhesive 4 injected into the through hole 11b from the outer bottom surface 11d side of the base frame, and the wide sealing is performed. At the boundary portion between the stop portion 34 and the lead-out wiring portion 32, the adhesive 4 wraps around between the lead-out wiring portion 32 and the base frame 11 (side wall of the through hole 11 b), and the lead-out wiring portion 32 is fixed to the base frame 11. The In particular, since the adhesive 4 completely closes the through hole 11b as in the above example even if the flexible portion Df is formed on the flexible wiring board 3, dust can be prevented from entering the motor.

  FIG. 11 is a longitudinal sectional view showing another configuration example of the motor according to the present invention. In addition, about the part which has the same function and structure as Example 1, the same code | symbol is attached | subjected here and detailed description is abbreviate | omitted. Here, the form of this motor is different from that of the first embodiment, and is an inner rotor type in which a rotor 2 (rotor) is provided on the inner periphery of the stator 1 (stator).

  The inner rotor type motor is mainly applied to a motor having a severe axial design restriction such as a 1.8 inch HDD. In this type, the stator core 13 can be installed on the outer side (position farther from the rotor shaft 21) and the rotor portion can be enlarged and designed in the axial direction. While having the advantage of being able to do so, there is no space in the base frame 11 for installing the flexible wiring board 3 (FPC) as in the structure shown in FIG. For this reason, a plate material called a shield plate 17 is attached to the base frame 11 above the stator core 13, and the flexible wiring board 3 is fixed to the surface of the shield plate 17 facing the base frame 11.

  Originally, the shield plate 17 does not leak the magnetic flux emitted from the stator core 13 or the field magnet 23 existing in the rotor portion, which is exposed in the inner rotor type, to the disk D which is a medium for recording information magnetically. For this purpose, in this example, the flexible wiring board 3 is fixed to the bottom surface of the shield plate 17, while the base frame 11 is mounted on the base frame 11 in the same manner as in the first embodiment inside the motor (outer periphery of the rotor hub 22 and the stator core 13. A through hole 11b leading to a portion adjacent to the inner bottom surface), and the flexible wiring board 3 is drawn from the inner bottom surface 11c side of the base frame 11 to the outer bottom surface 11d side opposite to the inner bottom surface through the through hole 11b.

  Even in such a mode, the wide sealing portion 34 is formed on the base frame 11 as shown in FIG. 12 by the adhesive 4 injected into the through hole 11b from the outer bottom surface 11d side of the base frame 11 as in the first embodiment. At the boundary between the wide sealing portion 34 and the lead-out wiring portion 32, the adhesive 4 wraps around between the lead-out wiring portion 32 and the base frame 11 (side wall of the through hole 11b). 32 is fixed to the base frame 11. In particular, as shown in FIGS. 5 to 10, even when the flexible wiring board 3 is formed with the bent portion Df, the adhesive 4 completely closes the through hole 11b as in the first embodiment, so that dust enters the motor. Can be prevented.

In the second embodiment, since the shield plate 17 is present, ultraviolet rays can be irradiated only from the outer bottom surface 11d side of the base frame 11. Therefore, the adhesive 4 is a thermosetting adhesive or the like in consideration of outgas. Use dry-curing adhesive.

1 is a longitudinal sectional view showing a configuration example of a motor according to the present invention. Partial enlarged sectional view of the motor Bottom view showing the lead-out part of the flexible wiring board Plan view showing flexible wiring board Cross-sectional view of a through hole through which a flexible wiring board is passed Explanatory drawing which shows the state which looked at the part of FIG. 5 from the motor exterior Explanatory drawing which shows the state which looked at the part of FIG. 5 from the inside of a motor Cross-sectional view showing another mode of through hole through which flexible wiring board is passed Plan view showing an example of changing the flexible wiring board Cross-sectional view showing another mode of through hole through which flexible wiring board is passed FIG. 5 is a longitudinal sectional view showing another configuration example of the motor according to the present invention. Partial enlarged view of FIG. Cross-sectional view of the main part showing a conventional example Illustration of conventional example Illustration of conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Base frame 11b Through-hole 11c Inner bottom face 11d Outer bottom face 13 Stator core 14 Stator coil 3 Flexible wiring board 31 Inner wiring part 31a Land part 32 Lead wiring part 34 Wide sealing part 4 Sealing material (adhesive)

Claims (9)

A base frame with a fixed stator core;
A rotor hub that is rotatably arranged on the base frame, is mounted with a field magnet facing the stator core in the radial direction, and supports a hard disk;
A stator coil formed by winding a conductor wire around the stator core;
A thin flexible wiring board for energizing the stator coil;
Equipped with,
The flexible wiring board is
An inner wiring portion disposed on an inner bottom surface side, which is a side on which the hard disk of the base frame is supported , having a land portion electrically connected to an end portion of the conductor wire;
A lead wiring portion led out from the inner bottom surface side to the outer bottom surface side opposite to the inner bottom surface through a long hole-shaped through hole formed in the base frame,
The width of the lead-out wiring portion is smaller than the longitudinal length of the through hole, and the lead-out wiring portion and the inner wiring portion are connected via a wide sealing portion larger than the width of the lead-out wiring portion,
The wide sealing portion is disposed at a position closing the through hole ,
A sealing material is injected into the through hole,
The hard disk drive motor according to claim 1, wherein the sealing material is continuous over the entire width of the lead-out wiring section between the base frame and the lead-out wiring section . 2. The motor for a hard disk drive device according to claim 1, wherein the wide sealing portion is disposed so as to close a peripheral portion of the through hole with a slight gap . The wide sealing portion, a hard disk drive motor according to claim 1 or claim 2, characterized in that said a wing-like protrusion which protrudes in the width direction on both sides of the lead wire sections. 4. The motor for a hard disk drive device according to claim 1 , wherein the wide sealing portion has a shape continuously connected to the inner wiring portion. 5. The hard disk drive motor according to claim 3 or 4 , wherein a width of the wide sealing portion is equal to or less than a longitudinal length of the through hole. The hard disk drive motor according to any one of claims 1 to 5 , wherein the flexible wiring board is bonded and fixed to the inner bottom surface. The flexible wiring board, a hard disk drive motor according to any one of claims 1 to 5, characterized in that it is fixed to the shield plate attached to the base frame. Edge of the lead-out wiring portion side of the wide sealing portion, to any one of claims 1 to 7, characterized in that it is arranged a gap is formed between the base frame The motor for hard disk drives described. 9. The hard disk drive device according to claim 1, wherein a boundary portion between the lead-out wiring portion and the wide sealing portion is fixed to the base frame by the sealing material. use motor.

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