JPH0884460A - Spindle motor - Google Patents

Abstract

PURPOSE: To maintain concentricity between a fixed-side stator and a rotor hub that is rotated and driven, eliminate the uneven rotation of the rotor hub, prevent read/write errors of a head, and improve ease of assembly. CONSTITUTION: A bracket 1 consists of a shaft securing tube 2 and a stator supporting tube 3 that are integrated with each other. The shaft securing tube 2 is fit into a base 7, and a fixed shaft 12 is fit into the bore 5 in the shaft securing tube 2. Thus concentricity is maintained between a stator 6, which is secured on the circumference of the stator supporting tube 3, and a rotor hub 15, which is supported on the fixed shaft 12, regardless of the base 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor for rotatably driving a recording medium such as a hard disk, and more particularly to a base having a stationary shaft and a stator support cylinder for holding a stator fixed to a stationary base of the apparatus. The present invention relates to an integrated spindle motor.

[0002]

2. Description of the Related Art There are various types of spindle motors for rotationally driving a recording medium. Among them, a base-integrated spindle motor in which a spindle motor is directly incorporated into a stationary side base of a hard disk drive is widely used. ing. 3 and 4 show the specific structure.

As shown in FIG. 3, the base 7a is formed by integrally forming a base base 27 fixed to the apparatus side and an annular support cylinder 28 standing from the base base 27. A shaft fixing hole 5a which is concentric with the support cylinder 28 is formed in the central portion. The fixed shaft 12a is fitted in the shaft fixing hole 5a, and the stator 6 is fixed to the outer circumference of the support cylinder 28. The rotor hub 15a is pivotally supported by the fixed shaft 12a via the upper bearing 13 and the lower bearing 14, and the cylindrical portion 16a on the center side of the rotor hub 15a, into which the outer rings of the upper and lower bearings 13 and 14 are fitted, is connected to the outer circumference thereof. The labyrinth gap 1 is formed between the support cylinder 28 and the inner surface thereof.
8a is inserted inside the support cylinder 28.
On the other hand, the yoke 19 and the rotor magnet 2 are provided on the inner surface of the large diameter portion 17a which is concentric with the cylindrical portion 16a of the rotor hub 15a.
0 is fixed. The rotor magnet 20 and the stator 12 are arranged to face each other with a gap in between. Further, the stator 6 is composed of a stator core 10, a coil 11 and the like as shown. A cap 22a is fitted over the upper surface of the rotor hub 15a so as to cover the upper bearing 13. The cap 22a is for preventing grease and the like from the upper bearing 13 and the lower bearing 14 from scattering to the disk chamber. Further, the rotor hub 15a is formed with a scraping hole 23 for mounting a recording medium (not shown) and a clamping screw hole 24.

Although the spindle motor shown in FIG. 4 has substantially the same structure as that of the spindle motor shown in FIG. 3, the structure of the support cylinder 28a is different. In the case of the spindle motor of FIG. 3, the support cylinder 2
8 is formed integrally with the base base 27, but the support cylinder 28a of this spindle motor is formed separately. That is, the base base 27 has an annular recess 29.
Is formed. On the other hand, an annular convex portion 30 that fits into the annular concave portion 29 is formed on the separate support cylinder 28a. Annular recess 2
9 and the annular protrusion 30 are fitted to each other to support the support cylinder 28a.
Are integrated with the base base 27. In FIG. 4, the same reference numerals as those in FIG. 3 denote the same or functional objects,
The description is omitted.

[0005]

In the case of a spindle motor, it is necessary to secure the concentricity between the fixed side support cylinders 28 and 28a for firmly holding the stator and the rotary side rotor hub 15a. If the concentricity is poor, the rotor hub 15a may have uneven rotation, resulting in problems such as head read / write errors and damage to the bearings. However, in the case of the spindle motor shown in FIG. 3, the support cylinder 28 has an integral structure with the base 7a, and a large size is required to machine the base 7a so as to maintain the concentricity of the support cylinder 28 and the shaft fixing hole. Since it is necessary to simultaneously process the base 7a while rotating, the processing of the base 7a becomes extremely complicated, and it is difficult to maintain desired concentricity. On the other hand, in the spindle motor shown in FIG. 4, since the support cylinder 28a and the base base 27 are separate bodies as described above, the above-mentioned problems are temporarily solved. However, it is difficult to maintain the accuracy of concentric processing between the annular recess 29 of the base base 27 and the shaft fixing hole 5a, and the work of assembling the annular recess 29 and the annular projection 30 to maintain the fitting accuracy is easy. However, there is a problem that it is difficult to maintain concentricity as a result.

The present invention solves the above problems, and the concentricity of the fixed side and the rotating side of the spindle motor is easily maintained, the rotor hub can be rotated stably and smoothly, and head read / write errors can be prevented. An object of the present invention is to provide a spindle motor that does not generate, has good assemblability, and does not cause damage to the bearing.

[0007]

In order to achieve the above object, the present invention provides a fixed shaft fixed to a base on the stationary side of an apparatus, and an outer periphery thereof fixed to the base concentrically with the fixed shaft. A spindle integrated with a base including a bracket having a stator fixed thereto, a rotor hub having a rotor magnet fixed at a position which is pivotally supported by the fixed shaft and faces the stator, and a recording medium or the like is mounted on an outer peripheral side thereof. In the motor, the bracket includes a small-diameter shaft fixing cylinder fitted to the base, a large-diameter stator supporting cylinder that firmly holds the stator, and the shaft fixing cylinder and the stator supporting cylinder concentric and integrated. And a fixed circular shaft that is coupled to each other, and constitutes the spindle motor in which the fixed shaft is fitted into the inner hole of the shaft fixing cylinder. That.

[0008]

The shaft fixing tube of the bracket is fitted in the shaft fixing hole of the base. The fixed shaft is fitted into the inner hole of the shaft fixing cylinder of the bracket. Therefore, it is possible to easily maintain the concentricity between the fixed shaft and the stator support cylinder. The stator is fixed to the stator support cylinder, and the rotor hub is pivotally supported on the fixed shaft, so that the stator side and the rotor hub side are held concentrically. When assembling the motor, for example, a bracket may be fitted to the base, the stator may be fixed to the stator support cylinder, and then the fixed shaft may be fitted to the shaft fixing cylinder of the bracket, or the stator support cylinder of the bracket may be previously fitted with the stator. May be fixed, and the bracket may be fitted to the base and then the fixed shaft may be fitted. In either case, the assembly work is easily performed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an axial sectional view showing the overall structure of this embodiment, and FIG.
FIG. 2 is an enlarged partial axial cross-sectional view showing the coil lead-out structure of the stator in FIG. 1.

As shown in FIG. 1, a bracket 1 is formed by integrally forming a small-diameter shaft fixing cylinder 2, a large-diameter stator supporting cylinder 3 concentric therewith, and an annular disc 4 connecting the two. Consists of. An inner hole 5 is concentrically formed in the shaft fixing cylinder 2. A stator 6 is fixed to the outer circumference of the stator support cylinder 3. On the other hand, a fixing hole 8 and a through hole 9 are formed through the base 7. The outer diameter of the shaft fixing cylinder 2 of the bracket 1 is fitted into the fixing hole 8. The stator 6 includes a stator core 10 and a coil 11.

The fixed shaft 12 has an outer diameter that fits into the inner hole 5 of the shaft fixing barrel 2 of the bracket 1, and has an inner ring 13a of the upper bearing 13 and an inner ring 14 of the lower bearing 14.
a is fitted.

The rotor hub 15 is composed of a cylindrical portion 16 near the center and a large diameter portion 17 on the outer peripheral side. The inner ring of the cylindrical portion 16 has an outer ring 13b of the upper bearing 13 and an outer ring 14b of the lower bearing 14.
Is fitted. Further, a labyrinth gap 18, which is a minute gap having a labyrinth sealing function, is formed between the outer periphery of the cylindrical portion 16 and the inner hole of the stator support cylinder 3. A yoke 19 is fixed to the inner surface of the large diameter portion 17 of the rotor hub 15, and a rotor magnet 20 is fixedly attached to the inner surface of the yoke 19. The rotor magnet 20 and the stator 6 are arranged to face each other with a minute gap 21 in between. Further, the cap 22 is fitted on the upper surface side of the rotor hub 15 to prevent the grease from scattering. Further, on the upper surface side of the rotor hub 15, a scraping hole 23 for mounting a recording medium (not shown) and a screw hole 24 for clamping are formed.

Next, a method of assembling the spindle motor of this embodiment will be described. First, the stator 6 is fixed to the bracket 1. The coil 11 of the stator 6 is connected to a pin 25, which will be described in detail later. Bracket 1 that holds stator 6
To the base 7. In this case, as will be described later in detail, the pin 25 is inserted into the through hole 9 of the base 7, the shaft fixing cylinder 2 of the bracket 1 is fitted into the inner hole 5 of the base 7, and the lower surface of the annular disc 4 of the bracket 1 is fixed. The connection between the bracket 1 and the base 7 is completed by contacting the upper surface of the base 7. Next, the fixed shaft 12 is fitted into the inner hole 5 of the shaft fixing cylinder 2. On the other hand, the rotor hub 15 has an upper bearing 13 and a lower bearing 14 fixed thereto. Rotor hub 15
The upper bearing 13 and the lower bearing 1
4 is fitted on the fixed shaft 12 and a bearing preload is applied to the balls 26. As described above, the fixed shaft 12 side and the rotor hub 15 side are assembled concentrically, and the stator 6 and the rotor magnet 20 of the rotor hub 15 are held concentrically with a predetermined gap.

The procedure for assembling the spindle motor is not limited to the above, but the bracket 1 is fitted to the base 7,
The stator 6 is firmly attached to the bracket 1, and the bracket 1
Alternatively, the fixed shaft 12 may be fitted to the fixed shaft 12. In addition, a rotor hub 15 is rotatably supported in advance on the fixed shaft 12 via an upper bearing 13 and a lower bearing 14 to form a so-called rotor assembly, and the fixed shaft 12 in this state is fitted to the bracket 1. You may In this case, bearing preload is applied in the rotor assembly.

Next, the lead-out connection structure of the coil 11 of the stator 6 will be described. First, a conventional technique will be described. As shown in FIG. 5, conventionally, a through hole 31 is provided in the base base 27, and an insulating bush 41 is fitted therein. The coil 11 of the stator 6 is pulled out and passed through the insulating bush 41, the coil 11 is pulled out to the lower side in the figure, and then connected to the power source side. In FIG. 6, a flexible circuit board (FPC) 32 is attached on the base 27 and the coil 11 is soldered and connected to this terminal. Further, in the conventional technique of FIG. 7, the conductive rubber connector 33 is fitted into the through hole formed in the base pedestal 27, and the flexible circuit board 32 on the base pedestal 27 and the HDD side arranged below the base pedestal 27. The terminal 35 of the circuit board 34 is connected via the conductive rubber connector 33, and the coil 11 and the circuit board 34 on the HDD side are connected.

In the coil connecting structure shown in FIGS. 5 to 7, the coil 11 is pulled out from the stator 6 after assembly, the base base 27 is passed through, and the coil 11 is soldered and fixed to the circuit board side. However, there is a problem that the workability is extremely poor and a soldering error is likely to occur.

As shown in FIG. 1 and FIG. 2, in the case of the spindle motor of this embodiment, the lead-out connection structure of the coil 11 is devised. That is, in this embodiment, the pin unit 36 is adopted. The pin unit 36 is composed of an insulating member 37 and a pin 25 or the like connecting the proximal end side to the insulating member 37. The coil 11 of the stator 6 passes through the insulating member 37, is wound around the pin 25, and is soldered and connected. On the other hand, a through hole 9 is bored in the annular disc 4 of the bracket 1, and the through hole 9
An insulating member 37 is fixed to the. Since the pin unit 36 is fixed to the bracket 1 side as described above, when the bracket 1 is fitted to the base 7 side, the through hole 9 of the base 7
The pin 25 of the pin unit 36 can be easily inserted therein. When the pin 25 is inserted, rubber 38 is inserted in the through hole 9.
Then, the pin 25 and the rubber 38 are hardened with an ultraviolet curable adhesive 39. By connecting the pin 25 to the circuit board side (not shown), the stator 6 and the circuit board are easily and reliably connected. Further, as shown in the figure, a sheet-shaped insulating material 40 made of polyester or the like is provided between the lower surface side of the insulating member 37 of the pin unit 36 and the upper surface of the base 7. This prevents the coil 11 from being short-circuited to the base 7 side. In the case of the lead-out connection structure of the present embodiment, unlike the prior art, it is not necessary to draw out or solder the coil 11 after assembly, so the coil 1
The connection work of 1 is extremely easily and surely performed.

[0018]

According to the present invention, the following remarkable effects are obtained. 1) By adopting a structure in which the shaft fixing cylinder and the stator supporting cylinder are integrally formed on the bracket, and after the fitting to the base, the fixing shaft is fitted into the inner hole of the shaft fixing cylinder. The concentricity with the stator fixed to is maintained, and as a result, the concentricity of the stator side and the rotor hub can be improved. 2) Since the stator support cylinder of the bracket and the shaft fixing cylinder can obtain the concentricity of the stator side and the rotor hub side, the hole drilling accuracy of the base is not required so much.
The base can be easily processed. 3) Stable rotation is obtained without uneven rotation of the rotor hub,
Head read / write error does not occur. 4) Since the concentricity is maintained, the bearing is not damaged. 5) Easy to assemble and improved assembling efficiency.

[Brief description of drawings]

FIG. 1 is an axial sectional view of an embodiment of the present invention.

FIG. 2 is an enlarged partial cross-sectional view showing a connection structure of a coil of a stator and a circuit board side in the embodiment of FIG.

FIG. 3 is an axial sectional view of a conventional spindle motor.

FIG. 4 is an axial sectional view of another conventional spindle motor.

FIG. 5 is a partial cross-sectional view for explaining a method of connecting a stator coil in a conventional spindle motor.

FIG. 6 is a partial cross-sectional view for explaining another coupling method of the coils of the stator in the conventional spindle motor.

FIG. 7 is a partial cross-sectional view for explaining still another coupling method of the coils of the stator in the conventional spindle motor.

[Explanation of symbols]

 1 Bracket 2 Shaft Fixed Cylinder 3 Stator Support Cylinder 4 Annular Disc 5 Inner Hole 6 Stator 7 Base 8 Fixed Hole 12 Fixed Shaft 13 Upper Bearing 14 Lower Bearing 15 Rotor Hub 20 Rotor Magnet

Claims (3)

[Claims] 1. A fixed shaft fixed to a non-moving side base of the apparatus, a bracket fixed on the base concentrically with the fixed shaft and holding a stator on the outer periphery thereof, and pivotally supported on the fixed shaft. A base-integrated spindle motor including a rotor hub or the like having a rotor magnet fixed to a position facing the stator and a recording medium or the like mounted on an outer peripheral side thereof, wherein the bracket has a small diameter fitted to the base. Of a shaft fixing cylinder and a large-diameter stator supporting cylinder that firmly holds the stator, and an annular disc that concentrically and integrally connects the shaft fixing cylinder and the stator supporting cylinder, and the fixed shaft fixes the shaft. A spindle motor fitted into an inner hole of a cylinder. 2. The rotor hub has a cylindrical portion near the center and a large-diameter portion on the outer peripheral side, the cylindrical portion being rotatably supported by the fixed shaft via a bearing, and the outer peripheral surface of the cylindrical portion and the outer peripheral surface of the cylindrical portion. 2. The spindle motor according to claim 1, wherein a labyrinth gap forming a labyrinth seal is formed between the stator support cylinder and the inner peripheral surface of the stator support cylinder. 3. A pin unit is disposed at a proper position on the annular disc, and the pin unit includes an insulating member fitted in a mounting hole of the annular disc and a pin having a base end side joined thereto. Having, the coil wire end portion of the stator fixed to the stator support cylinder is electrically connected to the pin,
The spindle motor according to claim 1, wherein the pin is led out through a through hole provided in the base.