JP3432361B2 - Spindle motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle motor applied to a drive device such as a floppy disk. More specifically, the present invention relates to a fixing structure for a stator core and a motor board.

[0002]

2. Description of the Related Art A spindle motor applied to a drive device such as a floppy disk has a stator core having windings wound around each salient pole mounted on a motor substrate.
However, since it is necessary to secure a winding space between the salient poles and the substrate, a spacer plate made of resin or the like is often sandwiched between the stator core and the substrate to float the stator core from the substrate. .

[0003]

However, in the structure in which the stator core and the spacer plate separate from each other are used to secure the winding space, the number of parts and the number of assembling steps increase, so that the cost of the spindle motor increases. There is.

Therefore, a structure is conceivable in which an auxiliary core plate is provided at the lowermost portion of the stator core without using the spacer plate as a separate member and the winding space is secured by this auxiliary core plate.
However, in this structure, since the auxiliary core plate is in contact with the motor board, even if the conductor pattern on the motor board is covered with the insulating layer, the insulating layer is damaged by the auxiliary core plate and the conductor pattern and the stator core are separated from each other. There is a problem of short circuit.

An object of the present invention is to solve the above problems and to bring about a significant cost increase.
An object of the present invention is to provide a spindle motor that can reliably insulate a conductor pattern on a motor board from a stator core.

[0006]

In order to solve the above-mentioned problems, the present invention provides a motor board having an insulating layer formed on the surface side of a conductor pattern, and a motor board fixed on the motor board to each salient pole. In a spindle motor having a stator core around which a winding is wound, the stator core includes an auxiliary core plate for securing a winding space between the salient pole and the substrate between the motor substrate and On the motor board
Passes through the auxiliary core plate and
Attach at least 3 screws to secure the motor board
One screw mounting hole is formed and the circumference of the screw mounting hole is formed.
In the enclosure, the conductor pattern is formed,
On the insulating layer that covers the conductor pattern, the screw
The area that overlaps the conductor pattern formed around the attachment hole
The insulating print layer is formed by silk printing
It is characterized by

In the present invention, the stator core and the
The motor board means that the auxiliary core plate is in contact with the printed layer.
It is in a fixed state in a closed state.

In the present invention, the auxiliary is provided at the bottom of the stator core.
A core plate is arranged and this auxiliary core plate is a conductor pattern.
It floats by the thickness of the printed layer and the printed layer. Therefore, the size
It is possible to secure a large winding space, and
However, because the number of parts and the number of assembly steps do not increase, significant cost
Not up. Also, the auxiliary of the surface of the motor board
In the area where the core plates overlap, an insulating layer is formed on the surface of the conductor pattern.
Not only that, because the insulating print layer is formed,
Since the edge layer is not scratched, the conductor pattern is
Do not short with the auxiliary core plate of the core.

Further , a conductor pattern is provided around the screw mounting hole.
Is formed and covers this conductor pattern.
On the insulation layer, the conductor pattern around the screw mounting hole and the
Insulation printing layer is formed by silk printing at
ing. Therefore, the motor board and the auxiliary core plate overlap.
Of the parts, the shortest around the screw mounting hole
It is possible to improve the insulating property in the easy part. Well
In addition, around the screw mounting hole, the convex portion is
Is formed on the surface of the motor board.
It is in a state of being floated by the thickness dimension of the printing layer. Therefore,
In the part where the motor board and the auxiliary core board overlap,
Body pattern Even if a printed layer is formed on the surface of the insulating layer
Good, but only for the conductor pattern around the screw mounting hole
Even if a printed layer is formed on the surface of the insulating layer,
This ensures reliable insulation between the taco core and the conductor pattern.
It Moreover, since there are three such parts, even if
Stator core is stable even if the motor board is distorted
Fixed in state.

In the present invention, the stator core includes a plurality of core plates having the salient poles and the auxiliary core plate made of the same material as the core plates. The core plate is preferably formed by laminating and crimping. According to this structure, since the auxiliary core plate and the core plate are made of the same material and are integrated by laminating and crimping, they can be manufactured by a series of pressing steps. Therefore, the stator core can be manufactured at low cost, and the cost of the spindle motor can be reduced.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a spindle motor to which the present invention is applied.

As shown in this figure, for example, a spindle motor 1 serving as a drive device for a 3.5-inch floppy disk or the like includes a rotor assembly 2 and a stator assembly 3.
It consists of and.

The rotor assembly 2 includes a rotating shaft 4, a cup-shaped rotor case 5 concentrically fixed to the rotating shaft 4, and a rotor magnet fixed to the inner peripheral surface of the rotor case 5 via a yoke 6. 7 and 7. Further, a hub base 9a is attached to the upper end surface of the rotor case 5 concentrically with the rotating shaft 4. Further, at a position displaced from the rotation shaft 4, the drive pin 9b projects from the groove 9c formed in the hub base 9a. A metal hub (not shown) attached to the center of the 3.5-inch floppy disk is held on the hub base 9a. A frequency power generating magnet 5a is attached to the outer peripheral surface of the rotor case 5. The frequency power generation magnet 5a faces a frequency power generation pattern (not shown), and the frequency power generation magnet 5a rotates together with the rotor assembly 2 to generate a frequency signal in the frequency power generation pattern. With this frequency signal, the rotation speed of the rotor assembly 2 can be detected. The rotor assembly 2 is supported by a thrust bearing 11 attached to a stator assembly 3 described below, and is rotatable about a rotary shaft 4.

The stator assembly 3 includes a motor board 10
A bearing holder 8 attached to a center hole 10a formed in the motor board 10, a thrust bearing 11 attached to the outer peripheral surface of the bearing holder 8, and a concentric arrangement with the thrust bearing 11 on the surface of the motor board 10. And a winding 14 wound around a salient pole 15b of the stator core 13.

As will be described later with reference to FIGS. 2 to 4, the stator core 13 has the same shape as that of the salient poles 15b.
It is composed of a single core plate 15 and an auxiliary core plate 12 having no salient poles. These are stacked with the auxiliary core plate 12 at the bottom. The auxiliary core plate 12 forms a space for the winding wire 14 between the salient pole 15b of the stator core 13 and the motor board 10.

FIG. 2 is a plan view of the stator core. FIG. 3 is a plan view of the auxiliary core plate used for the stator core. FIG. 4 is a sectional view of a portion corresponding to about ½ of the stator core.

As shown in FIG. 2, the core plate 15 has an annular base portion 15a and a plurality of salient poles 15b radially protruding from the base portion 15a at equal angular intervals. The tip of the salient pole 15b is a flange portion 15c that widens in the circumferential direction. The winding 14 is wound around the salient pole 15b. The auxiliary core plate 12 is
As shown in FIG. 3, an outer peripheral portion 12a having an E-shaped ring shape as a whole and formed in a substantially C shape, and protruding portions 12b and 12c protruding inward from both end portions of the outer peripheral portion 12a.
And a protruding portion 12d that protrudes inward from the central portion of the outer peripheral portion 12a. Outer peripheral portion 1 of the auxiliary core plate 12
2a has a shape that completely overlaps with the base portion 15a of the core plate 15,
The auxiliary core plate 12 and the core plate 15 are formed with three holes 13d at angular intervals of about 120 ° in the overlapping portion.

Here, the core plate 15 and the auxiliary core plate 12 are made of the same magnetic material. Also, the core plate 1
5 and the auxiliary core plate 12 are integrally formed by caulking in a laminated state. Outer peripheral portion 1 of the auxiliary core plate 12
As shown in FIG. 3, four caulking holes 12e are formed in the 2a at intervals. Therefore, as shown in FIG. 4, in a state where the three core plates 15 are stacked on the auxiliary core plate 12, the corresponding portion of the core plate 15 is directed toward the caulking hole 12e of the auxiliary core plate 12. These are integrated by pushing in with a press machine etc., and the stator core 1
3 is manufactured. The stator core 13 configured in this way
Are mounted and fixed on the motor substrate 10 shown in FIG.

FIG. 5 is a plan view showing the motor board.

As shown in this figure, the motor substrate 10 is
The bearing holder 8 has a central hole 10a in which the screw holder 10 is mounted, and three screw mounting holes 10b are formed around the central hole 10a at angular intervals of approximately 120 °. These screw mounting holes 10b are positioned so as to overlap the holes 13d formed in the stator core 13 when the stator core 13 is arranged on the motor board 10. Around the screw mounting hole 10b, a printing layer 19 described later is formed in a substantially C shape so as to surround the screw mounting hole 10b.

FIG. 6 is an explanatory view showing a state in which the portion A shown in FIG. 1 is enlarged.

As shown in this figure, the motor substrate 10 is
The base plate 10c is made of, for example, iron, an insulating base layer 18a that covers the base plate 10c, a conductor pattern 17 formed on the base layer 18a, and an insulating layer 18b that covers the entire surface. With respect to the motor board 10 having such a configuration, the screw 16 stopped from the screw mounting hole 10b penetrates the auxiliary core plate 12 and fits into the hole 13d of the stator core 13,
The stator core 13 and the motor board 10 are fastened together. However, with such a structure, when the insulating film 18b is damaged by the auxiliary core plate 12, the auxiliary core plate 12 and the conductor pattern 17 are short-circuited.

Therefore, in the present invention, in the portion where the motor board 10 and the auxiliary core plate 12 overlap, the conductor pattern 17 formed around the screw mounting hole 10b is provided on the surface of the insulating layer 18b that covers it. The insulating print layer 19 is formed by silk printing. Here, the printed layer 19 is processed even if the printed layer 19 is formed by printing the characters for displaying the component name, the mounting position of the component, etc. on the surface of the motor board at the same time as the silk printing. There is an advantage that the number of steps does not increase.

By doing so, in the portion where the motor board 10 and the auxiliary core plate 12 overlap, the screw mounting hole 10
Since the conductor pattern 17 is covered with the printed layer 19 in addition to the insulating layer 18b at the portion where the short circuit is most likely to occur, such as around b, the insulating property can be improved. Also,
Around the screw mounting hole 10b, a protrusion is formed by the thickness of the printed layer 19, so that the auxiliary core plate 12 is in a state of being floated from the surface of the motor substrate 10 by the thickness dimension of the printed layer 19. Therefore, the motor board 10 and the auxiliary core plate 12
In the portion where and overlap, the printed layer 19 may be formed on the surface of the insulating layer 18b for all the conductor patterns 17.
Even when the printed layer 19 is formed on the surface of the insulating layer 18b only for the conductor pattern 17 around the screw mounting hole 10b, the insulation between the stator core 13 and the conductor pattern 17 can be reliably achieved. Moreover, since there are three such portions, even if the motor substrate 10 is distorted, the stator core 12 is fixed in a stable state.

As described above, in the spindle motor 1 to which the present invention is applied, since the winding space is secured by the auxiliary core plate 12 formed at the bottom of the stator core 13, the number of parts and the number of assembling steps do not increase. Therefore, the cost does not increase significantly. Further, in the portion of the surface of the motor substrate 10 where the auxiliary core plate 12 overlaps, not only the insulating layer 18b but also the insulating printed layer 19 is formed on the surface of the conductor pattern 17, so that the insulating layer 18b is damaged. Because it is hard to attach,
The conductor pattern 17 is the auxiliary core plate 12 of the stator core 13.
Do not short circuit with.

Further, in the present invention, since the auxiliary core plate 12 and the core plate 15 are made of the same material and integrated by laminating and crimping, the stator core 13 can be manufactured by a series of pressing steps. Therefore, the stator core 13 can be manufactured at low cost, and the cost of the spindle motor 1 can be reduced.

[0028]

As described above, in the spindle motor of the present invention, a silk-printed insulating print layer is formed on the insulating layer that covers the conductor pattern at the portion of the stator core that overlaps with the auxiliary core plate. Has been done. For this reason, the insulating layer is not damaged by the auxiliary core plate, so that the stator core and the conductor pattern are not short-circuited.

[Brief description of drawings]

FIG. 1 is a sectional view showing a spindle motor to which the present invention is applied.

FIG. 2 is a plan view of a stator core.

FIG. 3 is a plan view showing an auxiliary core plate.

FIG. 4 is a sectional view of a portion corresponding to about ½ of the stator core.

FIG. 5 is a plan view showing a motor board.

FIG. 6 is an explanatory diagram showing a state in which an A portion of FIG. 1 is enlarged.

[Explanation of symbols]

1 Spindle motor 2 rotor assembly 3 Stator assembly 4 rotation axes 5 rotor case 7 rotor magnet 10 motor board 10b Screw mounting hole 11 bearings 12 Auxiliary core plate 13 Stator core 14 windings 15 core plate 15b salient pole 16 screws 17 conductor pattern 18b insulation layer 19 Printing layer

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Claims (3)

(57) [Claims] 1. A spindle motor comprising: a motor board having an insulating layer formed on the front surface side of a conductor pattern; and a stator core fixed on the motor board and having a winding wound around each salient pole. Is an auxiliary core plate for securing a winding space between the salient poles and the substrate, the motor substrate
And the motor substrate through the auxiliary core plate.
Attach the screws that fix the data core and the motor board.
At least three screw mounting holes are formed, and the conductor pattern is formed around the screw mounting holes.
And on the insulating layer covering the conductor pattern, the screw
The area that overlaps the conductor pattern formed around the attachment hole
A spindle motor, characterized in that an insulating printing layer is formed on the substrate by silk printing . 2. The stator core according to claim 1,
The motor board means that the auxiliary core plate contacts the printed layer.
Spind characterized by being fixed in contact
Lumotor. 3. The auxiliary core according to claim 1, wherein the stator core includes a plurality of core plates having the salient poles, and the auxiliary core plate made of the same material as the core plates. A spindle motor, wherein the plate and the plurality of core plates are laminated and caulked.