JPH07322543A - Spindle motor - Google Patents

Abstract

PURPOSE:To obtain a spindle motor producing a stabilized rotation by a structure wherein the cutting face of a copper foil lead-out part is disposed oppositely to a groove and a circuit board is fixed to a fixing member such that the groove is located at a lead-out hole. CONSTITUTION:A flexible circuit board 5 comprises a laminate structure of a base film, a copper foil part 10 and a cover film wherein the copper foil part 10 is covered with a cover film except the hatched parts. Each copper foil part 10 is connected with a copper foil lead-out part 13 being used at the time of electroplating wherein the cutting face of each copper foil lead-out part 1 is disposed oppositely to a groove 27 and fixed to the rear surface at a bracket part so that the groove 27 is located at the lead-out hole 4. Even if the copper foil sags from the cutting face of the circuit board 5, it does not slide on the rear surface at the bracket part and a current is fed positively from the circuit board 5 to the coil wire to produce stabilized rotation of rotor hub.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor mainly used for rotationally driving a recording disk or the like.

[0002]

2. Description of the Related Art A conventional spindle motor is shown in FIG.
As shown in FIG. 5, the fixing member 1, the stator 2 attached to the fixing member 1, the coil wire 3 provided on the lower surface of the fixing member 1, and drawn out from the stator 2 are formed in the fixing member 1. 4, a flexible circuit board 5 electrically connected to the rotor 4, a rotor hub 8 rotatably supported by the fixed member 1 through a pair of bearings 6 and 7, and a rotor magnet fixed to the rotor hub 8 and facing the stator 2. 9 and 9. And the circuit board 5
5 is formed in an approximately arc shape as shown in FIG. 5, the portion indicated by the broken line on the peripheral surface is the copper foil portion 10, and the portion indicated by the diagonal lines is the solder portion 11A to which the coil wire 3 is soldered and the power source. And the copper foil portion is exposed in both cases. The exposed copper foil portion oxidizes when exposed to air and causes rust, so gold plating is performed. Here, the gold plating process will be described with reference to FIG.

FIG. 6 shows a part of a substrate 12 in which four copper foil portions 10 are lined up on the same circumference, and the portions indicated by broken lines are all copper foil portions. This substrate 12 is formed by patterning a copper foil portion on an insulating base film, and further covering this with a cover film. Also,
The copper foil portion includes a copper foil portion 10 arranged on the same circumference, a copper foil lead-out portion 13 extending from each copper foil portion 10, and a collective electrode portion 14 to which each copper foil lead-out portion 13 is connected. The copper foil portions are covered with the cover film except for the portions corresponding to the solder portions 11A and the connection portions 11B. Then, such a substrate 12 is immersed in an electrolytic solution containing gold ions, and is exposed from the cover film by applying a negative potential through the connector to the collecting electrode portion 14 in a state where a positive potential is applied to this electrolytic solution. Gold adheres only to the copper foil portion in the shaded portion, that is, the solder portion 11A and the connection portion 11B, and is subjected to gold plating.

The substrate 12 that has been subjected to the gold plating process is pressed out into a substantially arc shape shown by a chain double-dashed line to complete the circuit board 5.

The completed flexible circuit board 5 is shown in FIG.
As shown in FIG. 6, the inner peripheral edge of the fixing member 1 was attached so that it was slightly displaced radially outward from the lead-out hole 4 formed in the fixing member 1.

[0006]

After the above-mentioned flexible circuit board 5 is plated with gold, the copper foil lead-out portion 13 is cut off in the middle of press-cutting. The cut surface 15 has copper foil. Often does not cut well and causes sagging of the copper foil. In such a conventional structure, the inner peripheral edge of the flexible circuit board 5 attached to the lower surface of the fixing member 1, that is, the cut surface 15 of the copper foil lead-out portion 13, is a lead-out hole formed in the fixing member 1. 4 is located at a position slightly outward in the radial direction with respect to No. 4, and has such a shape and size that the sagging of the copper foil is worn off on the lower surface of the fixing member 1 or near the entrance of the lead-out hole 4. . As a result, the current sent from the external power source to the circuit board 5 flows through the sag of the copper foil to the conductive fixing member 1, so that the motor does not reach the predetermined rotation speed, The desired motor characteristics cannot be obtained. Therefore, the rotational driving force of the motor and back electromotive force become insufficient,
Further, there is a problem that the electric current that has flowed to the fixing member 1 is transmitted to other parts that fix the fixing member 1.

Further, the coil wire 3 drawn out from the stator 2 is guided to the flexible circuit board 5 through the lead-out hole 4 formed in the fixing member 1. If the coil wire 3 rubs or hits the portion, the insulating coat coated on the coil wire 3 will come off. As a result, the current flowing through the coil wire 3 leaks,
It flows into the fixing member 1 which is electrically conductive, and the above-mentioned problems similarly occur.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a spindle motor capable of obtaining stable rotation.

[0009]

In order to achieve the above object, a spindle motor according to the present invention is provided with a fixing member, a stator attached to the fixing member, a lower surface of the fixing member, and the stator. A substantially arc-shaped flexible circuit board in which a coil wire drawn out from is electrically connected through a lead-out hole formed in the fixed member, and a rotor hub rotatably supported on the fixed member via a pair of bearings, In a spindle motor including a rotor magnet fixed to the rotor hub and facing the stator, the circuit board includes a base film, a copper foil portion patterned on the base film, and a cover film covering the copper foil. And a copper foil lead portion that is used during the plating treatment of the copper foil portion and is then cut A groove that guides the coil wire to the lower side of the circuit board is formed on the inner peripheral edge of the circuit board, and a cut surface of the copper foil lead-out portion is arranged so as to face the groove, and the circuit board, It is characterized in that the groove is attached to the fixing member so as to be located in the lead-out hole.

An insulating bush is provided on the stator side of the fixing member, and a cylindrical portion is provided on the insulating bush so as to cover the inner circumference of the lead-out hole. A coil wire from the stator is tubular. It is desirable to be led out through the inside of.

[0011]

In the above-described spindle motor of the present invention, the flexible circuit board is attached to the fixing member such that the arcuate groove formed in the flexible circuit board is located in the lead-out hole formed in the fixing member. Since it has been
Even if the copper foil is dripped on the cut surface of the copper foil lead-out portion after the processing of the flexible circuit board, the droop does not rub against the lower surface of the fixing member.

Further, if an annular insulating bush provided with a cylindrical portion covering the inner circumference of the lead-out hole is provided on the stator side of the fixing member, the fixing member in which the current flowing through the coil wire is conductive To prevent it from flowing. Furthermore, the insulation bush is
Because it is made of a relatively soft material such as resin,
Even when the coil wire pulled out from the stator passes through the lead-out hole covered with the insulating bush and is worn on the inner peripheral surface thereof, the insulating coat coded on the coil wire is not peeled off. Even if it comes off, the fixing member is covered with the insulating bush, so that the electric current is not transmitted to the fixing member.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments.

FIG. 1 is a right half sectional view showing an embodiment of a spindle motor according to the present invention, and FIG. 2 is a bottom view of a flexible circuit board provided in the spindle motor. 3A is a sectional view of the insulating bush, and FIG. 3B is a bottom view thereof.

In FIG. 1, 8 is a rotor hub, and the rotor hub 8 has a hub portion 22 and a shaft portion 23. Hub part 2
A rotor magnet 9 is annularly arranged on an annular side wall portion inside 2.

Reference numeral 1 denotes a fixing member, which is fixed to a base member (not shown) of the drive unit and also rotatably supports the rotor hub 8. The fixing member 1 is integrally formed with a bracket portion 24 and a cylindrical portion 25 having a cylindrical shape coaxial with the rotation axis.

The stator 2 is fitted and fixed to the outer peripheral portion of the cylindrical portion 25, and is arranged so as to face the rotor magnet 9. On the other hand, a pair of bearings 6 and 7 are fitted and fixed to the inner peripheral portion of the cylindrical portion 25, and the rotor hub 8 is rotatably supported via these.

Reference numeral 26 denotes a seal member, which covers the shaft portion 23, the bearing 7 and the lower surface of the cylindrical portion 25, and serves to enhance the airtightness in the motor.

On the lower surface of the bracket portion 24, the stator 2
A substantially arc-shaped flexible circuit board 5 is attached to which the coil wire 3 drawn from is electrically connected through a lead-out hole 4 formed in the bracket portion 24.

Reference numeral 27 is an arcuate groove for guiding the coil wire 3 from the stator 2 to the lower side of the flexible circuit board 5.

The flexible circuit board 5 has a laminated structure of a base film, a copper foil portion 10 and a cover film, and the other portions of the copper foil portion 10 except the hatched portion shown in FIG. 2 are covered with the cover film. ing. The soldered portion 11A, which is one shaded portion, is a portion to which the coil wire 3 drawn from the stator 2 is soldered, and the connecting portion 11B, which is the other shaded portion, is a connector (not shown) from the main body side of the hard disk device or the like. ) Is the part to be connected.

A copper foil lead-out portion 13 used during electroplating is connected to each copper foil portion 10, and an arcuate groove 27 is formed at a position corresponding to each copper foil lead-out portion 13. The cut surface of the copper foil lead-out portion 13 faces the groove 27. A circle indicated by a chain double-dashed line in FIG. 2 indicates the lead-out hole 4 formed in the bracket portion 24, and the flexible circuit board 5 is attached to the lower surface of the bracket portion 24 so that the groove 27 is located in the lead-out hole 4. ing.

As described in the conventional example, the cut surface 15 of the copper foil lead-out portion 13 is formed after the flexible circuit board 5 is pressed.
May cause sagging of copper foil. However, even if the copper foil sags, the flexible circuit board 5 is attached to the bracket portion 24 so that the cut surface 15 is located exactly in the lead-out hole 4, so that the sagging occurs on the lower surface of the bracket portion 24. There is no chance of passing.

Reference numeral 28 denotes an annular insulating bush, which is shown in FIG.
As shown in (a) and (b) of FIG. 4, the reinforcing member 29 is formed upright on the outer peripheral line, and four tubular portions 30 corresponding to the respective lead-out holes 4 of the bracket portion 24 are formed. The coil wire 3 is inserted into the lead-out hole 4 to cover the inner periphery thereof, and the coil wire 3 from the stator 2 is led out through the inside of the tubular portion 30.

Since the insulating bush 28 is attached to the portion of the fixed member 1 corresponding to the position of the stator 2 over the entire circumference, an insulating wire corresponding to the bracket portion 24 of the stator coil can be secured.

Even if the insulation coating of the coil wire 3 from the stator 2 is peeled off, the tubular portion 30 of the insulating bush 28 covers the inner circumference of the lead-out hole 4, and the coil wire 3 has the tubular portion 30. Since it is led out through the inside of, the electric current does not flow to the fixing member 1.

Although the embodiment of the spindle motor according to the present invention has been described above, the present invention is not limited to this embodiment, and various modifications can be made without departing from the scope of the present invention.

[0028]

Since the present invention is configured as described above, it has the following effects. After the flexible circuit board 5 is cut, the copper foil is not cut well on the cut surface of the copper foil lead-out portion 13 and the sagging of the copper foil occurs. However, a groove 27 for guiding the coil wire 3 drawn out from the stator 2 to the lower side of the circuit board 5 is formed on the inner peripheral edge of the circuit board 5, and this groove 27 is a lead-out hole formed in the bracket portion 24. 4, the circuit board 5 is attached to the lower surface of the bracket portion 24,
Even if the copper foil sags from the cut surface of the bracket 24
The copper foil does not drip on the lower surface of the coil, and the current sent through the circuit board 5 is surely supplied to the coil wire 3, and stable rotation of the rotor hub 8 is obtained.

Further, since an annular insulating bush 28 is provided on the side of the bracket 24 on the stator 2,
It is possible to prevent the coil wire 3 drawn out from the stator 2 from slipping on the inner circumference or corners of the lead-out hole 4, and to prevent the current flowing through the coil wire 3 from flowing through the fixed member 1, thus stabilizing the rotor hub 8. The obtained rotation is obtained.

[Brief description of drawings]

FIG. 1 is a right half sectional view showing an embodiment of a spindle motor according to the present invention.

FIG. 2 is a bottom view of the flexible circuit board in FIG.

3A and 3B show the insulating bush in FIG. 1, in which FIG. 3A is a sectional view and FIG. 3B is a bottom view.

FIG. 4 is a right half sectional view showing a conventional spindle motor.

FIG. 5 is a bottom view of the flexible circuit board in FIG.

FIG. 6 is a plan view for explaining the method of manufacturing the flexible circuit board.

[Explanation of symbols]

 1 Fixing Member 2 Stator 3 Coil Wire 4 Outlet Hole 5 Flexible Circuit Board 6 Bearing 7 Bearing 8 Rotor Hub 9 Rotor Magnet 10 Copper Foil Part 27 Groove 28 Insulation Bush 30 Cylindrical Part

Claims (2)

[Claims] 1. A fixing member, a stator attached to the fixing member, a coil wire provided on a lower surface of the fixing member, and drawn out from the stator electrically through a lead-out hole formed in the fixing member. A spindle motor comprising: a substantially arc-shaped flexible circuit board to be connected; a rotor hub rotatably supported by the fixing member via a pair of bearings; and a rotor magnet fixed to the rotor hub and facing the stator. The circuit board has a laminated structure of a base film, a copper foil portion patterned on the base film, and a cover film covering the copper foil, and the copper foil portion is plated with the copper foil portion. A copper foil lead-out portion used during processing and then cut is connected, and a groove for guiding the coil wire to the lower side of the circuit board is formed on the inner peripheral edge of the circuit board. Is, the copper cut surface of the foil deriving unit is disposed facing the groove, a spindle motor in which the circuit board, wherein the groove is attached to the fixed member so as to be positioned on the outlet hole. 2. An insulating bush is provided on the stator side of the fixing member, a cylindrical portion is provided on the insulating bush to cover an inner circumference of the lead-out hole, and a coil wire from the stator is tubular. The spindle motor according to claim 1, wherein the spindle motor is led out through the inside of the.