JP2000175403A - Mounting structure of motor substrate in motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mechanically and electrically positively connect a motor frame to a motor board, without much effort. SOLUTION: A through-hole 32 is formed in a motor board 30 of a motor so as to be overlaid on a land part 34, the motor board 30 is overlaid on a motor frame 40 so that the protrusion 42 of the motor frame 40 passes through the through-hole 32, and the protrusion 42 is then crushed. The crushed protrusion 42 spreads around the through-hole 32 of the motor board 30, and the motor board 30 is fixed to the motor frame 40. The crushed part of the protrusion 42 is connected to the land part 34 of the motor board 30, and it is possible to let the static electricity generated at the motor board 30 escape to the motor frame 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor board mounting structure for a motor in which a motor board for supplying current to an armature is mounted on a motor frame.
More specifically, the present invention relates to a mechanical and electrical connection structure between a motor frame and a motor board.

[0002]

2. Description of the Related Art As shown in FIG. 8 (a), for example, a motor used in a disk drive device of a floppy disk includes an armature 12 in which a winding coil 9 is wound around each salient pole 10, and an electric motor. It has a motor frame 20 made of an aluminum alloy for holding the child 12, and a motor board 30 attached to the bottom 22 of the motor frame 20 to supply current to the winding coil 9. Here, the motor frame 2
A pair of ball bearings 6 are supported at 0, and the rotating shaft 71 is rotatably supported by these ball bearings 6. A hub 70 is fixed to the rotating shaft 71, and the drive magnet 14 is fixed to the inner peripheral surface of the side plate of the hub 70 via a rotor core 76.

In mounting the motor substrate 30 on the bottom portion 22 of the motor frame 20 in the motor 1 configured as described above, the motor frame 20 and the motor substrate 3
A structure using riveting with a resin rivet that passes through 0 is disclosed in Japanese Utility Model Registration No. 3017024. However, the structure disclosed in this publication is effective as a technique for preventing an electrical short circuit,
The static electricity generated on the motor board 30 cannot be released.

Therefore, in place of the resin rivet, FIG.
As shown in (b), the bottom portion 22 of the motor frame 20 is enlarged, and a structure using a ground screw 79 (tapping screw) may be adopted. FIG. 8B shows the motor frame 30 upside down with respect to FIG. 8A so that the process of attaching the motor substrate 30 to the bottom 22 of the motor frame 20 is easy to understand. FIG. 9 shows the ground screw 7
9 is a process diagram when the motor substrate 30 is attached to the bottom portion 22 of the motor frame 20 using FIG.

[0005] As shown in FIG.
The motor substrate 3 is mounted on the bottom 22 of the motor frame 20 by using
To attach 0, first, a through hole 32 overlapping the land portion 39 is formed in the motor board 30, while a pilot hole 78 overlapping the through hole 32 is formed in the bottom portion 22 of the motor frame 20. . Then, after the mount of the motor substrate 30 is peeled off with tweezers (step ST1 in FIG. 9).
0), the through hole 32 of the motor board 30 and the motor frame 2
The motor substrate 30 is superimposed on the bottom portion 22 of the motor frame 20 so that the lower hole 78 overlaps with the lower hole 78 (step ST20 in FIG. 9). Next, the ground screw 79 is screwed in from the motor board 30 using a torque driver (step ST31 in FIG. 9). After that, ground screw 7
9 is coated with a screw lock 77 (step ST32 in FIG. 9). As a result, the bottom portion 22 of the motor frame 20
The motor board 30 is attached to the motor frame 30, and the head of the ground screw 79 and the land 39 of the motor board 30 are electrically connected to each other.
And are electrically connected. As a result, the land portion 39 of the motor board 30 is electrically connected to the motor frame 20 via the ground screw 79, so that the static electricity generated on the motor board 30 can be released to the motor frame 20.

[0006]

However, in the conventional mounting structure, it is necessary to screw the ground screw 79 using a torque driver after the through hole 32 of the motor board 30 and the lower hole 78 of the motor frame 20 overlap. Yes, all of these tasks are time-consuming. Also,
When the motor frame 20 is a cast product and the bottom portion 22 of the base frame 22 is as thin as about 0.6 mm,
The opening edge of the pilot hole 78 is chamfered at both the upper and lower sides.
In such a case, only one or two threads (grooves) are formed even when the ground screw 79 is tightened, so that the mechanical and electrical connection between the base frame 22 and the ground screw 79 is sufficiently secured. There is a problem that cannot be achieved. In such a case, it is impossible to increase the mechanical connection strength even if the connection is reinforced by the screw lock 77, while the electrical connection state is reduced by the screw lock 77.

[0007] In view of the above problems, an object of the present invention is to provide:
An object of the present invention is to provide a motor board mounting structure for a motor that can securely and mechanically connect a motor frame and a motor board without any trouble.

[0008]

According to the present invention, there is provided an armature having a winding coil wound around each salient pole, a motor frame for holding the armature, and a winding coil. In a motor board mounting structure for a motor having a motor board mounted on the motor frame to supply current to the motor frame, a protrusion formed on the motor frame is formed so as to overlap a land on the motor board. By being crushed through the through-hole, the motor substrate is attached to the motor frame, and the crushed protrusion is electrically connected to the land. It is characterized by the following.

In the present invention, a protrusion is formed on the motor frame, while a through hole is formed on the motor substrate so as to overlap the land portion, and the motor is mounted so that the protrusion of the motor frame passes through the through hole. After the board is overlaid on the motor frame, the protrusions are crushed and processed. As a result, the crushed protrusion spreads around the through hole of the motor substrate, and the motor substrate is sandwiched between the crushed portion of the protrusion and the motor frame and fixed to the motor frame. In this state, the crushed portion of the projection is connected to the land of the motor substrate, so that the static electricity generated on the motor substrate can be released to the motor frame.

In this way, when the motor frame and the motor board are mechanically and electrically connected to each other, according to the present invention, after the projection of the motor frame is passed through the through hole of the motor board, the projection is crushed. Since it is good, it is not necessary to perform the troublesome work of tightening the tapping screw with a torque driver after stacking the holes as in the past, and
No components such as tapping screws are required. Further, even if the motor frame is formed of a cast product and the thickness of the portion to which the motor frame is attached is as thin as about 0.6 mm, the protrusion formed on the motor frame is not mechanically fixed between the motor frame and the motor substrate. Further, a structure suitable for electrical connection can be formed, and there is no influence from the method of forming the motor frame or the thickness of a portion where the motor frame is mounted. Furthermore, when the motor frame is formed from a cast product, a conventionally used mold is
Since it is only necessary to cut away the portion of the motor frame to which the projection is to be formed as a concave portion, there is also an advantage that a conventionally used mold is not wasted.

In the present invention, a conductive material such as a conductive adhesive or solder is formed so as to cover the crushed protrusion and the land.
The mechanical and electrical connection between the motor frame and the motor board may be reinforced.

In the present invention, the projection may have a cylindrical shape, but at least the crushed portion has a hollow inside before the crushing so that the crushing is likely to cause plastic deformation. Is preferred. In this case, the protrusions may be completely cylindrical, or may be arranged so that a plurality of protrusions form one cylindrical shape.

In the present invention, the motor frame includes:
It is formed of an aluminum-silicon alloy, and the composition ratio of silicon in the aluminum-silicon alloy is preferably in the range of 1% by weight to 13% by weight with respect to aluminum. Aluminum-silicon alloys are more rigid than pure aluminum, and the higher the composition of silicon, the greater the rigidity (hardness). Therefore, an amount suitable for making a mechanical and electrical connection between the motor frame and the motor substrate (1% by weight to 13% by weight with respect to aluminum)
It is preferable that the motor frame is formed from an aluminum-silicon alloy containing silicon (up to the range). That is, the composition ratio of silicon is 1% by weight with respect to aluminum.
Below, the elastic deformation when crushing the projection is too large, the crushed projection returns to its original shape,
The reliability of the mechanical and electrical connection between the motor frame and the motor board is reduced. On the other hand, when the composition ratio of silicon exceeds 13% by weight with respect to aluminum, it becomes too brittle and cracks or the like are generated in the projections when the projections are crushed. The reliability of the mechanical and electrical connection with the substrate is reduced.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

(Schematic Structure of Entire Motor) FIGS. 1 and 2 are side views showing a motor according to the present embodiment with a part cut away, and an enlarged view of a main part of a motor substrate mounting structure in the motor. It is sectional drawing. However, in FIG. 2, the process of attaching the motor substrate to the bottom of the motor frame is shown in an upside-down state with respect to FIG.

The motor 1 shown in FIG. 1 is a motor applied to a 2.5 inch hard disk drive. The motor 1 rotates a rotating shaft 71 via a hub 70 holding a hard disk (not shown), a rotating shaft 71 extending downward from the center of the hub 70, and two ball bearings 5 and 6. And a motor frame 40 having a cylindrical portion 49 freely supported.
The stator core 10 is attached to the cylindrical portion 49 of the motor frame 40.
Are attached, and the coil 9 is wound around each salient pole of the stator core 10, thereby forming an armature 12.

The hub 70 has a cup shape with the opening facing downward, and the tip of the rotating shaft 71 is fixed to the center of the top plate 75. An annular rotor core 76 is fixed to the inner peripheral surface of the side plate of the hub 70, and the annular rotor magnet 14 is fixed to the inner peripheral surface of the rotor core 76 so as to face the armature 12. Therefore, by supplying current to the coil 9, the hub 70 rotates and the hub 7 rotates.
The hard disk mounted on the disk rotates.

(Motor board 30 to motor frame 40)
In the motor 1 configured as described above, the current supply to the coil 9 of the armature 12 is performed via the conductive pattern formed on the motor board 30 formed of a flexible printed board. That is, the motor substrate 30 is fixed in a state of being attached to the outer end surface of the bottom portion 41 of the motor frame 40.
The terminal of the coil 9 pulled out through a hole (not shown) formed in the bottom 41 of the motor frame 40 is processed.

In carrying out such fixing, in this embodiment, as shown in FIG. 2, a circular through hole 3 is formed in the motor substrate 30 at a position overlapping the land portion 34 of the motor substrate 30.
2 are formed. Here, a ground conductive pattern is connected to the land portion 34 on the motor board 30. On the other hand, among the bottom portion 41 of the motor frame 40, a columnar projection 42 is provided on the outer end surface 47 (the side opposite to the side where the armature 12 is located). Here, the protrusion 42 is in a crushed state, and the crushed protrusion 42 is in a state of spreading around the through hole 32 of the motor board 30. Therefore, the motor board 30 is sandwiched between the crushed portion of the projection 42 and the bottom 41 of the motor frame 40 and is fixed to the motor frame 40. In this state,
Since the crushed portion of the protrusion 42 is connected to the land 34 of the motor board 30, the static electricity generated on the motor board 30 can be released to the motor frame 40.

(Motor board 30 to motor frame 40)
The method of mechanically and electrically connecting the motor frame 40 and the motor board 30 in this manner is as follows.
This will be described with reference to FIGS. 3, 4, and 5. FIG. FIG. 3 is a process diagram when the motor board 30 is mounted on the motor frame 40. 4 and 5 are cross-sectional views each showing a state before the motor board 30 is mounted on the motor frame 40.
FIG. 4 is a cross-sectional view showing a state in which the motor board 30 is being mounted on the motor frame 40. Here, in FIGS. 4 and 5, as in FIG. 2, FIG. 1 and FIG.
Are shown upside down.

First, as shown in FIG.
And a motor frame 40 are prepared. Here, the motor frame 40 is, as shown in FIG.
The bottom 41 has a columnar projection 42 formed on an outer end surface 47 (the side opposite to the side where the armature 12 is located), and the motor substrate 30 is provided with an outer end surface 47 of the bottom 41 of the motor frame 40. A through hole 32 is formed at a position overlapping the projection 42 when the motor substrate 30 is stacked. This through hole 32
Are formed at positions overlapping the land portions 34 of the motor board 30. Here, the outer dimension of the base of the protrusion 42 is substantially equal to the inner diameter dimension of the through hole 32 formed in the motor board 30. In addition, since the motor frame 40 is a cast product made of an aluminum-silicon alloy integrally formed including the protrusion 42, the outer dimensions of the protrusion 42 are gradually reduced from the root toward the tip. In this embodiment,
The aluminum-silicon alloy used for the motor frame 40 has a silicon composition ratio in the range of 1% by weight to 13% by weight with respect to aluminum.

In order to mechanically and electrically connect the motor board 30 and the motor frame 40 configured as described above, the motor board 30 is peeled off from the backing paper (step ST10 in FIG. 3), and the outer end face 47 (the protrusion 42). ) Faces the motor frame 40 so that the upper surface 6 of the jig 60 faces upward.
0a is placed upside down.

Next, as shown in FIG. 5, the motor substrate 30 is overlaid on the outer end surface 47 of the bottom 41 of the motor frame 40 (step ST20 in FIG. 3). At this time, the protrusions 42 of the motor frame 40 are inserted into the through holes 32 of the motor board 30.
Penetrates.

Next, the projection 42 is crushed by the press head 62 disposed above. Here, since the head surface 620 of the press head 62 is curved and concave,
The protrusion 42 is crushed according to this shape (step ST30 in FIG. 3).

As a result, as described with reference to FIG. 2, the protrusion 42 has its tip 42a crushed into a hemisphere,
The crushed protrusion 42 extends around the through hole 32 of the motor board 30. Therefore, the motor board 30 is sandwiched between the crushed portion of the protrusion 42 and the bottom 41 of the motor frame 40 and is fixed to the motor frame 40. Also,
The crushed portion of the projection 42 connects to the land 34 of the motor board 30.

(Effect of this embodiment) As described above,
The mounting structure of the motor board 30 according to the present embodiment is configured such that when the motor frame 40 and the motor board 30 are mechanically and electrically connected, the protrusion 42 of the motor frame 40 is passed through the through hole 32 of the motor board 30. Since the protrusions 42 may be crushed, there is no need to perform the laborious work of tightening the tapping screws with a torque driver after overlapping the holes as in the related art, and there is no need for components such as tapping screws. is there. Further, the motor frame 40 is formed of a cast product, and the bottom
Even if the thickness of 1 is as thin as about 0.6 mm, the protrusions 42 formed on the motor frame 40 can be formed so as to be suitable for mechanical and electrical connection between the motor frame 40 and the motor board 30. It is not affected by the method of forming the motor frame 40 or the thickness of the portion to which the motor frame 40 is attached. Furthermore, when the motor frame 40 is formed of a cast product, it is only necessary to cut a portion of the motor frame 40 where the projection 42 is to be formed into a concave portion with respect to a conventionally used mold. There is also an advantage that the used mold is not wasted.

The motor frame 40 is made of an aluminum-silicon alloy, and the composition ratio of silicon in the aluminum-silicon alloy is in the range of 1% by weight to 13% by weight with respect to aluminum. Amount suitable for mechanical and electrical connection between the motor substrate 30 and the motor substrate 30 (1% by weight based on aluminum)
To 13% by weight) of silicon. That is, the composition ratio of silicon is 1% by weight with respect to aluminum.
Below, the elastic deformation when the projection 42 is crushed is too large, and the crushed projection 42 returns to its original shape, and the mechanical and electrical connection between the motor frame 40 and the motor board 30 is performed. The reliability of the device decreases. on the other hand,
If the silicon composition ratio exceeds 13% by weight with respect to aluminum, it becomes too brittle and cracks or the like are generated in the projections 42 when the projections 42 are crushed. In this case, the motor frame 40 and the motor substrate 30 And the reliability of the mechanical and electrical connection with the wire decreases. On the other hand, in the present embodiment, since the composition ratio of silicon is in the range of 1% by weight to 13% by weight with respect to aluminum, it has appropriate rigidity (hardness). When the crushing process is performed, the crushed projection 42 does not return to the original shape, and when the crushing process is performed, the projection 42 does not crack. Therefore, the mechanical and electrical connection structure between the motor frame 40 and the motor board 30 according to the present embodiment has high reliability.

FIG. 6 is a cross-sectional view showing a motor board mounting structure according to an improvement of the above embodiment. As shown in this figure, also in this example, when the motor frame 40 and the motor board 30 are mechanically and electrically connected, after the protrusion 42 of the motor frame 40 is passed through the through hole 32 of the motor board 30, The projection 42 is crushed. Furthermore, in this example, the crushed projection 4
2, and a conductive adhesive 50 (conductive material) is applied so as to cover the upper surface of the land portion 34 of the motor substrate 30.
Such a conductive adhesive 50 is obtained by mixing conductive particles such as silver and carbon with a resin component (adhesive component). Therefore, the protrusion 42 and the land 34 are mechanically reinforced by the caulking by the protrusion 42 and the adhesive force of the conductive adhesive 50, and the electrical connection is also reinforced by the conductive adhesive 50. I have.

The motor frame 40 and the motor board 3
As a conductive material that reinforces the mechanical and electrical connection with zero, a solder layer may be formed so as to cover the crushed projection 42 and the upper surface of the land portion 34 of the motor board 30.

[Modification 2 to the above embodiment] In the above embodiment, the protrusion 42 provided on the motor frame 40 is
Although the shape before processing was a simple columnar shape, the tip portion to be crushed has an inner side as shown in FIG. 7A so that the projection 42 spreads over a large area when crushed. Hollow (tubular) projection 4
2 may be formed. That is, the protrusion 42 shown here
The tip portion to be crushed has three protruding pieces 48.
Are arranged circumferentially, and the inside is hollow. Therefore, the press head 6 for crushing the projection 42
In the second head surface 620, the portions that each of the projections 48 hits are respectively curved and concave.

Accordingly, in this embodiment, the head surface 620 of the press head 62 can crush the three projections 48 with a relatively small force, and the projections 42 have a large area as shown in FIG. Crushed to spread over. Therefore, the motor frame 40 and the motor board 30
Can be reliably connected mechanically and electrically, and the motor board 30 can be prevented from being damaged by receiving an excessive load.

[0032]

As described above, according to the present invention, when the motor frame and the motor board are mechanically and electrically connected to each other, the protrusion of the motor frame is passed through the through hole of the motor board, and then the protrusion is formed. Since it only has to be crushed, there is no need to perform the cumbersome work of tightening the tapping screw with a torque driver after overlapping the holes as in the past,
Also, no components such as tapping screws are required. Also,
Even when the motor frame is formed of a cast product and the thickness of the portion to which the motor frame is attached is thin, the protrusions formed on the motor frame are suitable for mechanical and electrical connection between the motor frame and the motor board. The motor frame can be formed without being affected by the method of forming the motor frame or the thickness of the portion to which the motor frame is attached.
Furthermore, when the motor frame is formed of a cast product, the portion of the motor frame that is to be protruded may be cut into a concave portion with respect to the conventionally used mold. There is also an advantage that is not wasted.

[Brief description of the drawings]

FIG. 1 is a side view showing a motor to which the present invention is applied, with a part cut away.

FIG. 2 is an enlarged sectional view showing a main part of a mounting structure of a motor board in the motor shown in FIG.

FIG. 3 is a process diagram showing a procedure for attaching a motor substrate to a motor frame in the motor shown in FIG. 1;

FIG. 4 is a cross-sectional view showing a state before the motor substrate is mounted on the motor frame in the motor substrate mounting structure of the motor shown in FIG. 1;

FIG. 5 is a cross-sectional view showing a state where the motor board is being mounted on the motor frame in the motor board mounting structure of the motor shown in FIG. 1;

6 is a cross-sectional view of the mounting structure of the motor shown in FIG. 1 according to a first modification of the embodiment shown in FIGS. 2, 4 and 5;

FIGS. 7 (a) and 7 (b) each show a crushing process of a projection used in a second modification of the embodiment shown in FIGS. 2, 4 and 5 in the motor board mounting structure of the motor shown in FIG. 1; It is a perspective view showing a shape before, and a perspective view showing a shape after being crushed.

8A and 8B are half sectional views of a conventional motor,
FIG. 3 is an enlarged cross-sectional view showing a main part of a motor substrate mounting structure in the motor.

9 is a process chart showing a procedure for attaching a motor board to a motor frame in the motor shown in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor 5, 6 Ball bearing 9 Coil 10 Stator core 12 Armature 14 Rotor magnet 40 Motor frame 41 Bottom part of motor frame 30 Motor board (FPC) 32 Through hole 34 Land part 42 Projection 47 End face 48 Projection piece 50 Conductive adhesive 60 Receiving jig 62 Press head 70 Hub 71 Rotary shaft 76 Rotor core

Claims (4)

[Claims] 1. An armature having a winding coil wound around each salient pole, a motor frame holding the armature, and a motor board attached to the motor frame to supply current to the winding coil. In the mounting structure of the motor substrate in the motor having the above, the protrusion formed on the motor frame is passed through a through hole formed on the motor substrate so as to overlap the land portion, and is crushed. The motor substrate mounting structure for a motor, wherein the motor substrate is mounted on the motor frame, and the crushed protrusion is electrically connected to the land. 2. The mounting structure of a motor board according to claim 1, wherein a conductive material is further formed so as to cover the crushed protrusion and the land. 3. The motor substrate mounting structure according to claim 1, wherein at least the crushed portion of the protrusion is hollow inside before the crushing process. 4. The method according to claim 1, wherein
The motor frame is formed of an aluminum-silicon alloy, and a composition ratio of silicon in the aluminum-silicon alloy is 1% by weight to 13% by weight with respect to aluminum.
A mounting structure for a motor board in a motor, wherein