JPS62247748A - Spindle motor - Google Patents

Abstract

PURPOSE:To enlarge the effective flux of a stator coil, by making approximately constant the effective length of a conductor to form a print pattern of the stator coil along the axial direction of a rotor magnet facing the stator coil. CONSTITUTION:A cylindrical projection 10b with a through hole 10a is perpendicularly provided to a bracket 10 used in the installation of a spindle motor. A bearing 12 is inserted to the projection 10b to support a spindle shaft 11 pivotably. On the outside circumference of the projection 10b are inserted a stator yoke 14 made of cylindrical magnetic material and a stator coil 16 made of a cylindrical coil 15. The effective length of a conductor to form a print pattern of the stator coil 16 is kept approximately constant along the axial direction of a rotor magnet 20 facing the stator coil 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The invention relates to a spindle motor used as a drive source for a magnetic disk, etc., and particularly to a spindle motor used as a stator coil of the spindle motor. It is related to the structure of

[Prior Art] Conventionally, the above-mentioned spindle motor has been disclosed in Utility Model Registration Application No. 1599 filed in 1985 by the present applicant.
There is a spindle motor applied to ``Magnetic Disk Device No. 1 Magnetic Disk Device No. 83'', and the stator coil of this spindle motor has a conductor 2.2 spirally formed on the - side of the insulating sheet 1, as shown in Fig. 4. Sorting coil 3 is used.

As shown in detail in FIG. 5, the sheet coil 3 has two
100 μm on both sides of an insulating sheet 1 with a thickness of about 0 to 50 μm.
Copper foils 4.4 with a thickness of μm or less are pasted with adhesive 5.5 (Fig. 5 (A)), and these copper foils 4.4 are patterned with masking agent 6.6 (Fig. 5 (A)). Diagram (B)
), and a spiral print pattern (indicated by the symbol U in FIG. 1) is further formed by etching (FIG. 5(C)).

After covering both sides of the sheet coil 3 with an insulating film (not shown), the stator coil is wound into a cylindrical shape so as to be laminated on the outer peripheral surface of the stator yoke 7 as shown in FIGS. 6(A) and 6(B). It is something that turns.

"Problems to be Solved by the Invention" By the way, in the stator coil described above, the effective length of the conductor 2 per sheet coil 3 (the length of the conductor to generate the magnetic flux necessary for rotation of the motor) difference)
becomes smaller toward the center of the spiral, causing variations in the effective length of the conductor 2, which causes uneven rotation of the rotor magnet 8, which is provided at intervals on the outside of the stator coil. was there.

On the other hand, in the sheet coil 3 facing the rotor magnet 8, the conductor 2, which does not generate effective magnetic flux, is disposed over a wide area, so there is a natural limit to the improvement in the torque generated by the motor.

"Means for Solving the Problems" This invention has been made in view of the above circumstances, and is intended to prevent uneven rotation of the rotor and to prevent the occurrence of uneven rotation of the motor.
・The purpose is to obtain a spindle motor that improves the torque, and in order to achieve this purpose, a stator coil is provided whose outer circumferential surface faces the inner circumferential surface of the rotor magnet, and the stator coil has a conductor whose effective length is , is characterized in that it is configured with a printed pattern that is substantially constant along the axial direction of the rotor magnet.

"Function" According to the present invention, since the effective length of the conductor forming the printed pattern of the stator coil is substantially constant along the axial direction of the rotor magnet facing the stator coil, the stator The effective magnetic flux of the coil increases, and the torque generated by the motor improves.

"Example" Hereinafter, an example of the present invention will be described with reference to FIGS. 1 to 3.

First, the basic structure of the entire spindle motor will be explained with reference to FIG. 3. In the figure, reference numeral IO is a bracket used when attaching the spindle motor. The bracket IO has a cylindrical protrusion 10 having a through hole 10a.
b is provided vertically, and a bearing I2 that rotatably supports the spindle shaft 11 is inserted into the protrusion 10b with the same axis, and a ring-shaped seal member 1 is inserted into the protrusion 10b.
3 is fitted into the through hole 10a and the spindle shaft 11.
It is designed to create a seal between the

On the other hand, a stator yoke 14 made of a cylindrical magnetic material is provided on the outer periphery of the protrusion 10b.
A stator coil 16 consisting of a cylindrical coil 15 and a cylindrical coil 15 arranged concentrically is fitted therein.

Further, at the tip of the spindle shaft 11, there is a spindle hub 17 on which a plurality of magnetic disks (shown in the figure) are mounted.
is installed. The spindle hub I7 is composed of a cylindrical part 17a and a flan part 17b, and on the inner periphery of the cylindrical part 17a, there is a cylindrical ring magnet 18 and a magnetic field that prevents leakage of magnetic flux from above and below the ring magnet 18. A rotor magnet 20 consisting of shielding members +9A and 19B is fixed. The stator coil 16 and rotor magnet 20 constitute a so-called inside hub spindle motor.

Next, the configuration of the coil 15 will be explained.

This coil 15 is connected to an insulating sheet 2 as shown in FIG.
A sheet coil 31 formed by forming 8 spiral print patterns 30, 30, . It is triple laminated on the outer circumferential surface of the . and,
The conductors 32, 32, . . . forming the front eight self-printed patterns 30, 30, .
As shown by reference numerals in FIG. 1, the lengths in the direction (direction) are approximately the same as or greater than the height of the stator yoke 14. Further, the conductors 32, 32, located in the coil center portion 15a are arranged in the axial direction of the stator yoke 14 (
(direction of arrow m-n), along the axial direction of the Zunaichi rotor magnet 20.

As shown in FIG. 1, the coil 15 has a central portion (
15a) is disposed on the outer circumferential surface of the stator yoke I4, and a band-shaped portion (indicated by code +5b) along the upper side and a band-shaped portion (indicated by 15c) along the lower side are arranged on the outer peripheral surface of the stator yoke I4. 14, and these folded parts 15d and 15e are provided with iron support members 36 for fixing the coil I5, as shown in FIG. 2(B). ing. The support member 36 abuts against the inner circumferential surface of the stator yoke 14 and a ring-shaped support portion 36a136b that is disposed at the upper and lower ends of the stator yoke 14 and supports the folded portions 15d and 15e of the coil 15, respectively. and a cylindrical support portion 36c that prevents magnetic flux from leaking into the interior.

In the spindle motor configured as above,
By sequentially switching the direction of the current flowing through the coil 15, the rotor magnet 20 rotates and the magnetic disk is driven.

In the stator coil 16 of the spindle motor shown in
5a conductor 32, 32,... or the rotor magnet 2
Since the coil 16 is provided with a substantially constant length along the axial direction of the coil 16, there is no unevenness in the rotating magnetic field generated along the circumferential direction of the coil 16, thereby making the rotation of the rotor magnet 20 uniform. Ru.

Furthermore, since the conductors 32, 32, .

On the other hand, in the above spindle motor, the stator coil 1
6, the effective magnetic flux generation range is wider than that of a conventional spindle motor, so if the same amount of torque as a conventional spindle motor is to be generated, the magnetic force per unit area of the rotor magnet 20 is reduced and the rotor magnet 20 is The thickness of the magnet 20 can be reduced, and it is possible to reduce the weight and weight of the magnet 20.

In addition, the upper part 15b of the coil I5 where no effective magnetic flux is generated.
Since the lower portion 15c is folded back toward the inner peripheral surface of the stator yoke I4, the rotation of the rotor magnet 20 is not adversely affected.

In addition, in the above stator coil, the device current is 2A.
As long as the above can be ensured, the adjacent spiral printed patterns 30, 30, . . . may be connected to the power source in parallel or in series. Further, as shown in FIG. 2(C), the coil I
The stator yoke 14 of No. 5 may be bonded.

"Effects of the Invention" As explained in detail above, according to the present invention, the effective length of the conductor constituting the printed pattern of the stator coil is made substantially constant along the axial direction of the rotor magnet. , the rotating magnetic field generated along the circumferential direction of the stake coil is uniform, and the rotation of the rotor magnet becomes uniform. Furthermore, since the effective magnetic flux is larger than that of a conventional spindle motor, the torque generated by the motor can be directed.

[Brief explanation of drawings]

1 to 3 are diagrams showing the configuration of an embodiment of the present invention, in which FIG. 1 is a plan view showing the sheet coil in an expanded state, and FIG. 2(A) is a stator coil and rotor magnet. Fig. 2 (B) is a plan view showing the relationship between the sheet coil and the stator yoke;
Figure (C) is a perspective view showing another aspect of the stator yoke, Figure 3 is an exploded perspective view of the spindle motor, and Figures 4 to 6 are diagrams used to explain the conventional spindle morph. , Fig. 4 is a plan view showing the expanded state of the note coil, Figs. 5(A) to 5(C) are sectional views of the sheet coil, and Fig. 6(A) is a diagram showing the relationship between the stator coil and rotor magnet. FIG. 6(B) is a plan view showing the relationship, and FIG. 6(B) is a perspective view showing how the sheet coil is attached to the stator yoke. lO... Bracket 10b Projection 11 Spindle shaft 12 Bearing 14 Stator yoke 16 Stator coil 17 Spindle hub 20 Rotor magnet 29 Insulation note 30 Print Pattern 3I...Sheet coil 32 conductor

Claims (1)

[Scope of Claims] 1. A bearing fitted into a bracket, a spindle shaft fitted to this bearing, and a hollow body that concentrically surrounds this spindle shaft and is fixed to the spindle shaft and rotates together with the bearing. a spindle hub; a rotor magnet provided on the inner periphery of a hollow portion of the spindle hub; A spindle motor comprising a stator coil fixed to a bracket, wherein the stator coil is configured with a printed pattern such that the effective length of the conductor is substantially constant along the axial direction of the rotor magnet. spindle motor. 2. The stator coil is a sheet coil formed by forming a spiral printed pattern on the top surface of an insulating sheet, and is wound around a cylindrical stator yoke, and the stator coil does not function effectively with respect to the rotor magnet. The spindle motor according to claim 1, characterized in that the spindle motor is disposed outside the facing surface of the rotor magnet.