JPH0759326A - Disk driving motor - Google Patents

Abstract

PURPOSE:To obtain a disk driving motor capable of making the size smaller or the thickness thinner while maintaining a sufficient performance. CONSTITUTION:In a disk driving motor, a thrust pad 2 supported in axial direction by a fixing shaft 1 fixed to a stator is formed inside a recessed portion 3a at one end of a linkage pin 3 fixed to a rotor having a hub base, and the outside diameter of the linkage pin 3 has the dimensions of outside diameter corresponding to the central hole of the disk. Peripheral wall of the recessed portion 3a of the linkage pin 3 can be used as a radial bearing. Part of the linkage pin 3 can be used as the hub base. The fixing shaft 1 can be formed by a sintered material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk drive motor for rotationally driving a floppy disk or the like.

[0002]

2. Description of the Related Art A motor for rotating a disk medium such as a floppy disk is known. 11 to 13 show a conventional example of such a motor. Figure 1
In FIG. 1 and FIG. 13, a hole is formed on the substrate 37, and the thrust bearing 32 is attached to this hole. A cylindrical bearing holder 43 is attached to the outer periphery of the thrust bearing 32. A cylindrical radial bearing 36 is fitted and fixed to the inner peripheral surface of the bearing holder 43, and the rotary shaft 31 is inserted in the center of the radial bearing 36. The lower end of the rotary shaft 31 is in contact with the thrust bearing 32, and the rotary shaft 31 is supported by the thrust bearing 32 in the thrust direction. The rotary shaft 31 is rotatably supported by a radial bearing 36.

A flange 43 is provided below the bearing holder 43.
a is formed, and the stator core 41 is placed on the upper surface of the flange 43a. The stator core 41 is configured by stacking core bodies, and a plurality of salient poles are formed on the outer circumference, and a coil 42 is wound around each salient pole. On the other hand, a spacer 44 is interposed between the substrate 37 and the stator core 41. Stator core 41
Is a screw 9 that penetrates the stator core 41 and the spacer 44.
0 is fixed by being screwed onto the substrate 37. Further, the bearing holder 43 is fixed to the substrate 37 by pressing the flange 43 a of the bearing holder 43 toward the substrate 37 by the inner peripheral edge of the stator core 41.

A substantially disk-shaped hub base 34 is attached to the tip end of the rotary shaft 31 by press fitting or the like, and a cup-shaped rotor case 35 is attached to the lower surface of the hub base 34 by caulking or the like. ing. Rotor case 3
A ring-shaped drive magnet 38 is attached to the inner surface of the peripheral wall of No. 5. The inner surface of the drive magnet 38 faces the salient poles of the stator core 41 with a certain gap. For this reason, the drive magnet 38 and the rotor case 35 are rotationally driven, and the rotary shaft 31 is rotationally driven, by energizing the coil 42 wound around the salient pole.

A hole is formed in the rotor case 35 at a specific position outside the hub base 34, and a drive pin 45 supported by a leaf spring or the like is arranged inside the hole.

A media hub 46 such as a floppy disk is mounted on the upper surface of the hub base 34. As shown in FIG. 12, a drive pin engaging hole 47 and a spindle engaging hole 48 are formed in the media hub 46, and the drive pin engaging hole 47 is formed.
The drive pin 45 and the tip of the rotary shaft 31 are engaged with the spindle engaging hole 48 and the spindle engaging hole 48, respectively.
6 is positioned and locked on the hub base 34, and is rotationally driven.

[0007]

In recent years, disk drive motors have been made thinner and smaller. In FIG. 13, the diameter φ of the rotary shaft 31 is most effective for thinning and downsizing.
d1 downsizing, the axial dimension L4 of the sliding portion between the rotary shaft 31 and the radial bearing 36, or the axial dimension L5 of the hemispherical portion that abuts the thrust bearing 32 at the lower end of the rotary shaft 31. Etc. However, it is difficult to downsize while maintaining sufficient performance by the above method.

For example, if the diameter φd1 of the rotary shaft 31 is reduced, it becomes impossible to accurately position the media hub 46. Further, if the dimension L4 of the sliding portion of the rotary shaft 31 and the radial bearing 36 is shortened, the shaft runout accuracy of the rotary shaft 31 deteriorates, and the rotary shaft 31 and the radial bearing 36.
Wear will shorten the life of the motor. Further, if the radius of curvature of the hemispherical portion is increased in order to reduce the size L5 of the hemispherical portion at the lower end of the rotary shaft 31, the contact portion with the thrust bearing 32 increases, so noise increases. It should be noted that if a hemispherical portion is formed only on a part of the lower end of the rotary shaft 31 that comes into contact with the thrust bearing 32, sufficient characteristics can be obtained, but it is difficult to process and the cost rises.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a disk drive motor which can be made compact or thin while maintaining sufficient performance. To do.

[0010]

The invention according to claim 1 is
A thrust receiving portion axially supported by a fixed shaft fixed to the stator is formed in a recess at one end of an engaging pin fixed to a rotor having a hub base, and the outer diameter of the engaging pin is a disc. It is characterized in that it has an outer diameter dimension corresponding to the center hole of the.

The invention according to claim 2 is characterized in that the peripheral wall of the recess of the engaging pin is a radial bearing.

The invention according to claim 3 is characterized in that a part of the engaging pin serves as a hub base.

According to a fourth aspect of the present invention, the fixed shaft is formed of a sintered material.

The invention according to claim 5 is characterized in that a convex portion is formed at one end of the fixed shaft, and the convex portion is fitted to the substrate.

The invention according to claim 6 is characterized in that the fixed shaft has a contact surface with the substrate.

The invention according to claim 7 has a core fixed to a stator, and a part of the core is pressed against a fixed shaft.

The invention according to claim 8 is characterized in that at least one point of the engaging pin, the radial bearing and the fixed shaft is impregnated with lubricating oil.

According to a ninth aspect of the present invention, the axial dimension of the shaft fixing hole of the substrate is larger than the thickness dimension of the substrate.

[0019]

The thrust receiving portion formed in the recess at one end of the engaging pin contacts the fixed shaft, and the engaging pin is supported in the thrust direction. The engaging pin rotates integrally with the rotor having the hub base. The engaging pin engages with the disc hub,
The outer diameter of the engagement pin is set to a sufficiently large size suitable for positioning the disk hub, and the disk hub can be positioned with high accuracy. Moreover, since the thrust receiving portion formed on the engaging pin is brought into contact with the fixed shaft mounted on the substrate to support the engaging pin in the thrust direction, it is possible to reduce the thickness and size while maintaining the performance.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a disk drive motor according to the present invention will be described below with reference to the drawings. In FIG. 1, an engaging pin 3 having a hemispherical end and engaged with a spindle engaging hole of a disc hub (not shown) is formed by sintering powder of stainless steel or the like.
The diameter dimension φd1 of the engagement pin 3 is set to the most suitable dimension for accurately positioning the engagement pin 3 in the spindle engagement hole of the disk hub. A recess 3b is formed at the lower end of the engagement pin 3, and the outer periphery of the recess 3b is a peripheral wall 3a. A thrust receiving portion 2 that is hemispherical and has a smooth finish is formed in the center of the bottom of the recess 3b. A hub base 4 on which a disc or the like is placed is attached to the outer periphery of the engagement pin 3. A rotor case 5 is fixed to the outer peripheral edge of the lower surface of the hub base 4 by caulking or the like. The rotor case 5 is formed in a cup shape, and a drive magnet is attached to the inner surface of the peripheral wall of the rotor case 5, but the peripheral wall of the rotor case 5 and the drive magnet are not shown. Further, the drive pin 45 is arranged in the rotor case 5 as in the conventional example, but this is also not shown. The manufacturing method of the engagement pin 3 is not limited to the powder sintering method, and other manufacturing methods such as casting, plastic working such as pressing, cutting, and injection molding sintering method may be used. Also, the material of the engagement pin 3 is not limited to stainless steel,
Other materials such as steel and copper alloy may be used.

A cylindrical radial bearing 6 is press-fitted into the center hole of the hub base 4 from below. At the upper end of the radial bearing 6, the outer peripheral edge of the center hole 6b projects upward to form a protrusion 6a, and the protrusion 6a is press-fitted into the center hole of the hub base 4. The upper end surface of the protrusion 6 a is in contact with the lower end surface of the engagement pin 3. A rotor set is composed of the engaging pin 3, the hub base 4, the rotor case 5, the radial bearing 6, the drive magnet 38 (not shown), and the drive pin 45.

On the other hand, a hole is formed in the center of the substrate 7, and the fixed shaft 1 is press-fitted and fixed in the hole. The fixed shaft 1 has a center hole 6b of a radial bearing 6 which constitutes the rotor set.
Is inserted, and the thrust receiving portion 2 of the engaging pin 3 and the upper end surface of the fixed shaft 1 contact each other, so that the rotor set is supported in the thrust direction. Also, the fixed shaft 1 and the fixed shaft 1
The rotor assembly is rotatably supported by the fixed shaft 1 by a radial bearing 6 covering the outer peripheral surface of the rotor with a constant gap.

According to the disk drive motor as described above, the shaft involved in the rotation of the rotor set (the fixed shaft 1 in this case)
Since the engaging pin 3 that engages with the center hole of the disc hub is not integrated but is configured separately, the outer diameter dimension φd1 of the engaging pin 3 is most suitable for accurately positioning in the center hole of the disc hub. It is possible to reduce the outer diameter dimension φd2 of the fixed shaft 1 that supports the rotor set while reducing the size of the motor to a suitable size. Further, since a part of the upper end of the radial bearing 6 is inserted into the center hole of the hub base 4, the dimension L4 of the sliding portion of the radial bearing 6 with the fixed shaft 1 is set.
Height L of the disk drive motor without shortening
2 can be shortened by the amount of the protrusion 6a inserted into the center hole of the hub base 4, and the thickness can be reduced.

Further, since the thrust receiving portion 2 is installed inside the hub base or the engaging pin 3, the thrust receiving portion 2 can be thinned by the axial dimension L5 of the hemispherical portion of the lower end portion of the rotary shaft 31 in the conventional example. It will be possible. Here, the radius of curvature of the hemispherical thrust receiving portion 2 is set to be the same as the radius of curvature of the hemispherical portion at the lower end of the rotary shaft 31 in the conventional example. For this reason, noise generated when the rotor set rotates and the thrust receiving portion 2
Wear can be maintained at the same level as conventional products. Further, if the engaging pin 3 is formed by a powder sintering method of stainless steel or the like, an injection molding sintering method, or the like, various shapes can be easily manufactured at a relatively low cost.

When the disk drive motor having the above-described structure is formed in the same size as the conventional example, the radial bearing 6
Since it is possible to secure a large dimension L4 of the sliding portion with the fixed shaft 1, it is possible to further improve the shaft runout accuracy.

In order to rotate the rotor assembly smoothly, as shown in FIG. 2 (a), a lubricating oil 10 such as grease is interposed at a portion where the thrust receiving portion 2 and the upper end portion of the fixed shaft 1 are in contact with each other. May be. In addition, as shown in FIG. 2B, in the contact portion between the thrust receiving portion 2 and the fixed shaft 1, the portion on the engagement pin 3 side is a flat surface, and the upper end of the fixed shaft 1 that abuts on this flat surface. The part may be hemispherical. Further, as shown in FIG. 2C, a thrust bearing 11 made of synthetic resin or the like is mounted on the flat bottom surface of the recess 3b formed on the engagement pin 3 side, and the thrust bearing 11 has a semi-spherical fixed shaft. You may make it contact an upper end part. This makes it possible to rotate the rotor set more smoothly.

In the example of FIG. 1, the engaging pin 3 and the radial bearing 6 are fixed to the hub base 4, but the radial bearing 6 may be directly fixed to the engaging pin 3. For example, as shown in FIG. 3A, the axial dimension of the peripheral wall 3a of the engagement pin 3 is set to be relatively long, and the protrusion 6a of the radial bearing 6 is press-fitted and fixed to the inner surface of such peripheral wall 3a. Alternatively, as shown in FIG. 3 (b),
The axial dimension of the peripheral wall 3a may be set longer to cover most of the outer circumference of the radial bearing 6 with the peripheral wall 3a. Further, as shown in FIG. 3 (c), the upper side of the center hole 6b of the radial bearing 6 is a large diameter portion, and the small diameter peripheral wall 3a of the engagement pin 3 is press-fitted into this large diameter portion so that the end face of the peripheral wall 3a is The upper end surface of the radial bearing 6 may be brought into contact with the end surface of the engagement pin 3 outside the peripheral wall 3a, respectively, on the stepped surface of the center hole 6b.

As yet another embodiment, as shown in FIG. 4, a press or the like is applied to the rotor case 5 between the end surface of the engagement pin 3 outside the small-diameter peripheral wall 3a and the upper end surface of the radial bearing 6. Alternatively, the engaging pin 3, the radial bearing 6, and the rotor case 5 may be fixed by sandwiching the edge portion of the central hole of the protruding portion 5a which is formed as a hub base. By doing so, the hub base 4 as a separate member can be omitted, so that the cost can be reduced.

As yet another embodiment, as shown in FIG. 5, a sleeve 13 may be fitted around the radial bearing 6. The sleeve 13 can prevent leakage of bearing oil and the like and minimize the influence of the bearing oil on other parts, particularly when the radial bearing 6 is formed of a sintered oil-impregnated bearing or the like. It is valid.

As yet another embodiment, as shown in FIG. 6, a flange 3c may be formed on the outer periphery of the engagement pin 3, and the upper end surface of the flange 3c may be a hub base on which a disk or the like is placed. Since a hub stand as a separate member is not required, the cost can be reduced, and the lower surface of the flange 3c contacts the upper end surface of the rotor case 5, so that the perpendicularity of the rotor case 5 with respect to the engagement pin 3 can be improved. You can

Next, an embodiment of the disk drive motor in which the engagement pin and the radial bearing are integrally formed will be described. In FIG. 7, an engaging pin 3 having a semi-spherical tip and engaging with a center hole of a disc hub (not shown) is formed in a bottomed cylindrical shape. The outer diameter φd1 of the engagement pin 3 is set to the most suitable size for accurately positioning the engagement pin 3 in the center hole of the disk hub. A concave portion 3b is formed in such an engagement pin 3. The peripheral wall 3a of the engagement pin 3 having the recess 3b also serves as a radial bearing. Recess 3b
A thrust receiving portion 2 that is hemispherical and has a smooth finish is formed at approximately the center of the bottom portion of the. A rotor case 5 is fixed to the outer periphery of the peripheral wall 3a. The rotor case 5 is
The portion outside the engagement pin 3 is a protrusion 5a,
The upper surface of the protruding portion 5a serves as a hub base on which a disc or the like is placed.

On the other hand, a hole is formed in the center of the substrate 7, and the fixed shaft 1 is press-fitted and fixed in this hole. The recess 3b of the engagement pin 3 of the rotor set including the engagement pin 3 and the rotor case 5 is fitted to the fixed shaft 1 so that the rotor set is rotatably supported. The upper end surface of the fixed shaft 1 contacts the thrust receiving portion 2 of the engagement pin 3 to support the rotor set in the thrust direction. Also, the engagement pin 3
The peripheral wall 3a covers a large part of the fixed shaft 1 with a certain minute gap, and supports the rotor set in the radial direction.

According to the embodiment as described above, in addition to the effect that it can be made thinner while maintaining the same performance as the conventional product as in the example of FIG. 1, the engaging pin 3
Since the peripheral wall 3a is a radial bearing, the number of parts can be reduced and the manufacturing cost can be reduced. If the peripheral wall 3a is formed by a powder sintering method such as stainless steel or an injection molding sintering method, the peripheral wall 3a has a bottomed cylindrical shape as shown in FIG.
A shape in which the portion a is long in the axial direction can be easily formed without increasing the cost. Further, since the rotor case 5 is projected upward on the outer peripheral side of the engagement pin 3 to form the projecting portion 5a, which is used as the hub base, the number of parts can be further reduced, and the manufacturing cost can be reduced. You can

Further, the peripheral wall 3a of the engagement pin 3 may be impregnated with lubricating oil as required. When it is worried that the lubricating oil may leak from the outer surface of the peripheral wall 3a, the outer surface of the peripheral wall 3a may be crushed, or the sleeve 13 as shown in FIG. Is preferably attached.

Further, as shown in FIG. 8A, a flange 1c may be formed on the lower end side of the fixed shaft 1 so that the upper surface of the substrate 7 and the lower surface of the flange 1c are brought into contact with each other. By doing so, the perpendicularity of the fixed shaft 1 can be improved. Further, a flange 3c is formed on the outer peripheral surface of the engagement pin 3 attached to the upper end of the fixed shaft 1 to form a hub base, and the lower surface of the flange 3c is brought into contact with the upper surface of the rotor case 5. Good. By doing this, the engagement pin 3
The verticality of the rotor case 5 with respect to can be improved.

In addition to the above configuration, FIG.
As shown in (b), a tongue piece 14a may be formed on the stator core 14, and the tongue piece 14a may press the upper surface of the flange 1c of the fixed shaft 1. According to this example, FIG.
The fixing strength of the fixed shaft 1 can be further improved as compared with the above example.

As a method of obtaining the perpendicularity of the fixed shaft 1 with respect to the substrate 7, as shown in FIG. 9A, a small-diameter protrusion 1f is formed at the base end of the fixed shaft 1 and the protrusion 1f is formed. There is also a method of press-fitting and fixing the substrate 7. Since the stepped portion 1e of the fixed shaft 1 main body and the protruding portion 1f contacts the upper surface of the substrate 7,
The perpendicularity of the fixed shaft 1 can be improved. In addition to this, as shown in FIG. 10, the axial dimension of the protrusion 1f may be larger than the plate thickness of the substrate 7. According to this example,
Since a part of the protruding portion 1f protrudes from the back surface of the substrate 7, this protruding portion can be used as a positioning member when the disk drive motor is attached to another member, and the motor can be easily positioned. Further, in order to improve the strength of the fixed shaft 1, as shown in FIG. 9B, the outer periphery of the fixed shaft 1 may be pressed and held by the protrusion 14b which is a part of the stator core 14. Alternatively, FIG.
As shown in (c), a burring portion 7c may be formed on the substrate 7 and the fixed shaft 1 may be press-fitted into the burring portion 7c. According to the example of FIG. 9C, the fixed shaft 1
Since the contacting portion between the substrate 7 and the substrate 7 increases, the fixing strength can be remarkably improved.

[0038]

According to the first aspect of the invention, the thrust receiving portion axially supported by the fixed shaft fixed to the stator has the recessed portion at one end of the engaging pin fixed to the rotor having the hub base. Since it is formed inside, it can be made smaller or thinner by that amount, and if it is a disk drive motor of the same physique, it is possible to improve shaft runout accuracy and obtain high torque. Further, since the outer diameter of the engagement pin can be set to the outer diameter corresponding to the center hole of the disk, the positioning accuracy of the disk hub is high.

According to the second aspect of the invention, since the peripheral wall of the recess of the engaging pin is a radial bearing, it is not necessary to use the radial bearing as a separate component, and the number of components can be reduced.
The manufacturing cost can be reduced.

According to the third aspect of the present invention, since a part of the engaging pin serves as a hub base, the number of parts can be reduced also from this point, and the manufacturing cost can be reduced.

According to the fourth aspect of the invention, since the fixed shaft is made of a sintered material, it is possible to form fixed shafts of various shapes at low cost.

According to the fifth aspect of the present invention, the convex portion is formed at one end of the fixed shaft, the convex portion is fitted to the substrate, and the dimension of the convex portion is larger than the thickness of the substrate. The convex portion protruding from can be used as a positioning member of the disk drive motor, and positioning of the motor becomes easy.

According to the sixth aspect of the invention, since the fixed shaft is formed with the contact surface with the substrate, the perpendicularity of the fixed shaft to the substrate can be improved.

According to the invention as set forth in claim 7, since a part of the core fixed to the stator is pressed against the fixed shaft, the fixing strength of the fixed shaft can be improved.

According to the invention described in claim 8, the engaging pin,
Since at least one point of the radial bearing and the fixed shaft is impregnated with the lubricating oil, the rotor can be smoothly rotated.

According to the ninth aspect of the invention, since the area of the fitting portion between the substrate and the fixed shaft is large, the fixing strength of the fixed shaft can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a disk drive motor according to the present invention.

2A to 2C are cross-sectional views showing another example of a contact portion between a fixed shaft and an engagement pin of a disk drive motor according to the present invention.

3A to 3C are sectional views showing another example of fixing a radial bearing of a disk drive motor according to the present invention.

FIG. 4 is an enlarged sectional view of an essential part showing another embodiment of the disk drive motor according to the present invention.

FIG. 5 is an enlarged sectional view of an essential part showing still another embodiment of the disk drive motor according to the present invention.

FIG. 6 is an enlarged cross-sectional view of an essential part showing still another embodiment of the disk drive motor according to the present invention.

FIG. 7 is an enlarged sectional view of an essential part showing still another embodiment of the disk drive motor according to the present invention.

8A and 8B are cross-sectional views showing another example of an engagement pin and a fixed shaft applied to the disk drive motor according to the present invention.

9A to 9C are sectional views showing another example of a fixed shaft applied to a disk drive motor according to the present invention.

FIG. 10 is a sectional view showing another example of a fixed shaft applied to the disk drive motor according to the present invention.

FIG. 11 is a sectional view showing an example of a conventional disk drive motor.

FIG. 12 is a plan view showing a state where the disk drive motor locks the media hub.

FIG. 13 is an enlarged cross-sectional view of the main part of the same.

[Explanation of symbols]

 1 fixed shaft 2 thrust receiving portion 3 engaging pin 3a recessed portion 6 radial bearing 7 substrate

Claims (9)

[Claims] 1. A disk drive motor, wherein a thrust receiving portion axially supported by a fixed shaft fixed to a stator is provided in a recess at one end of an engagement pin fixed to a rotor having a hub base. A disk drive motor characterized in that the outer diameter of the engagement pin is formed according to the center hole of the disk. 2. The disk drive motor according to claim 1, wherein a peripheral wall of the recess of the engagement pin is a radial bearing. 3. The disk drive motor according to claim 1, wherein a part of the engagement pin serves as a hub base. 4. The disk drive motor according to claim 1, wherein the fixed shaft is made of a sintered material. 5. The disk drive motor according to claim 1, wherein a convex portion is formed at one end of the fixed shaft, and the convex portion is fitted on the substrate. 6. The disk drive motor according to claim 1, wherein the fixed shaft has a contact surface with the substrate. 7. The disk drive motor according to claim 1, further comprising a core fixed to the stator, wherein a part of the core is pressed against the fixed shaft. 8. The disk drive motor according to claim 1, wherein at least one of the engagement pin, the radial bearing, and the fixed shaft is impregnated with lubricating oil. 9. The disk drive motor according to claim 1, wherein an axial dimension of a shaft fixing hole which constitutes a part of the stator and in which a fixed shaft is fitted and fixed is larger than a thickness of the substrate. .