JPH09167431A - Disk rotating drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve recording and reproducing characteristics by supporting a rotary shaft fitted with a turntable to a chassis by a radial bearing in the radial direction and also a thrust bearing in the thrust direction respectively. SOLUTION: The shaft is supported by the thrust bearing 57 having a large diameter D to be supported in the thrust direction of a boss member 42 used in common with the turntable. Consequently, tripping of the rotary shaft 40 is prevented by the thrust bearing 57, and also the rotary shaft 40 is stabilized on the chassis 7 in the right and left direction by the radial bearing 38, thereby suppressing backlash of the rotary shaft 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk rotating apparatus having a rotating shaft rotatably supported by a chassis and rotationally driven by a motor, and a turntable attached to the rotating shaft for rotating the disk. The present invention relates to a drive device, and is particularly suitable for application to a micro floppy disk device.

[0002]

2. Description of the Related Art A conventional example of a micro-floppy disk rotation driving device will be described with reference to FIG.

First, a spindle motor 1 of this micro-floppy disk rotation driving device is composed of a rotary shaft 2 composed of a motor shaft, a rotor 3, a stator 4 and a turntable 5. Then, a pair of upper and lower bearings 9 and 10 are incorporated in the boss portion 8 provided on the chassis 7 of the disk rotation drive device, and both bearings 9 and 10 are incorporated.
The motor shaft 2 is rotatably supported by the lower part thereof in a vertical manner. A radial rolling bearing is used for the upper bearing 9, and a radial sliding bearing made of a metal bearing is used for the lower bearing 10.

Next, on the outer periphery of the central portion of the motor shaft 2, a rotor boss 12 corresponding to the flange-shaped member in the present invention is provided.
Is fixed by press-fitting or adhesion, and this rotor boss 1
The rotor 3 is horizontally attached to the rotor 2. The rotor 3 includes a disk-shaped yoke 13 having a central opening and a ring-shaped magnet 14 fixed to the lower surface of the rotor 13. The inner peripheral portion 13a having a small diameter of the yoke 13 has a rotor boss 1.
It is fixed to the outer peripheral portion of 2. The stator 4 is horizontally arranged below the rotor 3. The stator 4 includes a plurality of coils 17 formed on the lower surface of a printed circuit board 16 and a yoke 18 fixed on the chassis 7. That is, the motor 1 is a flat motor in which the rotor 3 and the stator 4 face each other in a plane.

Next, the turntable 5 is mounted horizontally above the motor shaft 2. The turntable 5 includes a disk-shaped turntable main body 20 forming a chuck yoke and a magnet plate 21 fixed to an upper surface thereof and forming a chuck magnet.
The inner periphery of the turntable body 20 is fixed to the outer periphery of the upper portion of the motor shaft 2 by press-fitting, bonding, or the like. A drive pin support lever 22 is attached to the lower surface of the turntable body 20, and a drive pin 23 is vertically fixed on one end of the lever 22. The drive pin 23 projects upward through a drive pin insertion hole 24 provided in the turntable body 20. In addition,
The lever 22 is moved and urged by a tension spring (not shown) such that the drive pin 23 is moved and urged in a direction away from the center of the turntable 5 on the front side in the rotation direction of the turntable 5.

By the way, the micro floppy disk (hereinafter referred to as "disk") 26 which is rotationally driven by the motor 1 is rotatably housed in a cartridge case 27 composed of upper and lower halves 27a and 27b. . A central disc 28 made of a metal plate is fixed to the central portion of the disc 26, and a central hole 29 and a drive pin insertion hole 30 are provided at the center of the central disc 28 and a position eccentric from the central disc 28. There is. The center hole 29 is formed in a square shape, and the drive pin insertion hole 30 is formed in a rectangular shape. The center disk 28 is loosely fitted in a turntable insertion hole 31 provided in the lower half 27b.

When the cartridge case 27 is inserted into the disk rotation driving device constructed as described above, the disk 26 is horizontally mounted on the turntable 5 of the spindle motor 1, and the center disk 28 of the disk 26 Is mounted on the turntable body 20, and the center hole 29 of the center disk 28 and the drive pin insertion hole 30 are inserted into the upper part of the motor shaft 2 and the drive pin 23. Then, so-called magnet chucking in which the center disk 28 is attracted by the magnet plate 21 of the turntable 5 is performed.

After the chucking of the disk 26 is completed in this way, when a current is sequentially passed through the plurality of coils 17 of the stator 4 of the motor 1, this current links with the magnetic flux of the magnet 14 of the rotor 3. Since the rotor 3 is rotated, the motor shaft 2 is rotated. As a result, the turntable 5 is rotated, and the disk 26 chucked on the turntable 5 is driven to rotate. At this time, the drive pin 23 presses the outer peripheral side 30a of the drive pin insertion hole 30 so that the disk 26
Since the central disk 28 of the central disk 28 is urged to move away from the center of the turntable 5, the central hole 29 of the central disk 28 is
Edge 29a contacts the outer periphery of the upper portion of the motor shaft 2, and the center of the disk 26 is positioned at the center of the turntable 5. Further, as the turntable 5 rotates, the drive pin 23 presses the peripheral surface of the drive pin insertion hole 30 to rotate the disk 26. And disk 2
The desired recording / reproduction is performed by a magnetic head (not shown) contacting the recording surface of 6.

[0009]

However, the above-mentioned conventional micro-floppy disk rotation driving device has the following problems.

That is, in the conventional disk rotation drive device, surface runout of the rotor 3 as shown by arrow a in FIG. 4 and surface runout of the turntable 5 as shown by arrow b due to rattling of the motor shaft 2 are prevented. For this purpose, it is necessary to separate the pair of radial bearings 9 and 10 by a large amount in the vertical direction. Therefore, if the height of the bearing structure including the pair of radial bearings 9 and 10 is reduced, rattling of the motor shaft 2 is likely to occur, and if the rattling of the motor shaft 2 is to be eliminated, the height of the bearing structure increases. There is a problem that the disk rotation drive device cannot be made thin because it becomes large.

Therefore, according to the present invention, the height of the bearing structure for supporting the rotary shaft including the motor shaft to which the turntable is attached is reduced to make the disk rotary drive thinner, and the rattling of the rotary shaft is reduced. This is to prevent it as much as possible.

[0012]

According to the present invention, there is provided a disk rotation driving device as described above, wherein a flange member attached to a rotary shaft and a radial bearing for supporting the rotary shaft in a radial direction with respect to a chassis. A thrust bearing that supports the rotary shaft in the thrust direction with respect to the chassis by rotatably supporting the flange-shaped member on the chassis, the thrust bearing from the axial direction of the rotary shaft. As seen, while being configured to be arranged at an outer position of the radial bearing between the flange-shaped member and the chassis, the radial bearing is viewed from a direction orthogonal to the axial direction of the rotary shaft, It is configured so as to at least partially overlap the thrust bearing in the axial direction of the rotary shaft.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a micro-floppy disk rotation driving device will be described below with reference to FIGS. The above

2. Description of the Related Art The same parts as those of the prior art described in the section of the prior art are denoted by the same reference numerals and the description thereof will be omitted.

First, in the disk rotation driving device of the present embodiment, a radial slide bearing 38 is incorporated in a boss portion 37 provided on the chassis 7 of the disk rotation driving device, and the radial bearing 38 is incorporated into the motor of the spindle motor 35. A shaft (which constitutes a rotating shaft in the present invention) 40 is vertically rotatably inserted in a lower portion thereof.
Therefore, the motor shaft 40 is supported by the radial bearing 38 in the radial direction with respect to the chassis 7. The length of the motor shaft 40 is shorter than the length of the conventional motor shaft 2 shown in FIG. The radial bearing 3
Although a radial sliding bearing composed of a metal bearing is used for 8, a radial rolling bearing may be used.

Next, a turntable-cum-boss member (which constitutes a flange-shaped member in the present invention) 42 is attached to the outer periphery of the motor shaft 40 from the substantially central portion to the upper portion. The boss member 42 is formed by integrally molding a cylindrical boss portion 43 and a disc-shaped turntable portion 44 that horizontally extends outward from the upper portion of the boss member 42. The inner peripheral portion of the boss portion 43 of the boss member 42 is fixed to the outer periphery of the motor shaft 40 substantially from the center to the upper portion by press-fitting or bonding.

Next, a rotor 46 is attached to the outer peripheral portion of the turntable portion 44 of the boss member 42. A disk-shaped yoke 47 having a central opening of the rotor 46 has an inner peripheral portion 47a formed with a large diameter, and the inner peripheral portion 47a is formed on an annular support portion 48 formed on the outer peripheral portion of the turntable portion 44. Fixed. That is, a fitting groove 49 is formed on the outer peripheral surface of the annular support portion 48, and the inner peripheral portion 47 a of the disc-shaped yoke 47 is fitted into the fitting groove 49.

Next, as shown in FIG. 3, on the upper surface of the boss member 42, the inner peripheral portion of the boss portion 43 projects upward to form an annular projection portion 43a, and the turntable portion thereof. The outer peripheral portion of the protrusion 44 projects upward to form an annular protrusion 48a.
Since the protruding lengths and height positions of “a” and “48a” are substantially the same, an annular concave portion 45 is formed between these protruding portions 43a and 48a. A magnet plate 21 that constitutes a chucking magnet is arranged on the inner periphery of the annular concave portion 45. Therefore, the annular projection 43a, the annular recess 45, and the annular projection 48a are sequentially arranged in a direction away from the axis of the motor shaft 40.
1, and a circumferential portion 47a of a disk-shaped yoke 47 is fixed to a support portion 48 on which the annular projecting portion 48b is formed. Therefore, the boss member 42 and the magnet plate 2 attached to the boss member 42
The thickness of the composite structure composed of the first and yoke 47 is small in spite of the large vertical height of the inner peripheral portion of the boss portion 43.

Next, as shown in FIG. 3, the outer peripheral portion of the turntable portion 44 projects downward to form an annular projection 48.
The supporting portion 48 is formed by the projection 48b, the projection 48a, and the outer periphery of the turntable portion 44 between the projections 48a, 48b. A groove 49 is formed. The lower end of the projection 48b is located above the lower end of the boss 43. Further, since the inner peripheral portion of the boss portion 43 protrudes downward to form a protrusion 43b similar to the protrusion 43a, the inner peripheral portion of the boss portion 43 has a protrusion length of the upper and lower protrusions 43a and 43b. Only the boss part 43
Is longer in the up-down direction than the outer peripheral portion.

Next, the rotor 46 is attached to the outer peripheral portion of the turntable portion 44 of the boss member 42, so that the space 50 is secured below the turntable portion 44. In this space 50, a drive pin support lever 52 having a drive pin 23 is arranged. That is, as shown in FIG. 1, a substantially arc-shaped lever 52 is pivotally supported on the lower surface of the turntable portion 44 by the support shaft 53. The drive pin 23 is connected to a tension coil spring 5 stretched between a spring locking pin 54 fixed to the lower surface of the turntable portion 44 and the other end of the lever 52.
5, the turntable portion 44 is urged to move in the direction away from the center of the turntable portion 44 on the front side in the rotational direction of the turntable portion 44.

Next, a thrust bearing 57 is interposed between the lower end surface of the boss portion 43 of the boss member 42 and the upper end surface of the boss portion 37 of the chassis 7. This thrust bearing 57 is
The thrust rolling bearing may be composed of a plurality of steel balls 59 supported by a ring-shaped holder 58. In this case, a pair of ring-shaped substrates 60 and 61 that sandwich the plurality of steel balls 59 from above and below can be provided as needed. In addition, a shaft supporting portion of the thrust bearing 57 (a circle passing through the respective ball centers of the plurality of steel balls 59)
Since the diameter D of does not affect the height of the motor 35,
It can be made large enough. Further, in order to prevent the motor shaft 40 from falling down by the thrust bearing 57,
The raceway surface of the base plate 60 above the thrust bearing 57 (steel ball 59
The contact surface with) is set to be orthogonal to the axis of the motor shaft 40. Further, the structure of the bearing 57 can be variously changed as long as it is a thrust bearing.

Therefore, the thrust bearing 57 rotatably supports the turntable-cum-boss member 42 on the chassis 7 via the upper substrate 60 and the lower substrate 61,
As a result, the motor shaft 40 is supported in the thrust direction with respect to the chassis 7 via the turntable-cum-boss member 42. Further, as is apparent from FIG. 2, the thrust bearing 57 is arranged at an outer position of the radial bearing 38 between the turntable / boss member 42 and the chassis 7 when viewed from the axial direction of the motor shaft 40. . Furthermore, FIG.
As is apparent from the above, the upper surface 38a of the radial bearing 38 is
Is the upper surface 61a of the lower substrate 61 (in other words, the steel ball 5
Since the radial bearing 38 is positioned above the lower end 9 of the motor shaft 40, the radial bearing 38 is located in the axial direction of the motor shaft 40 when viewed from the direction orthogonal to the axial direction of the motor shaft 40.
7 at least partially overlaps. Therefore, the height of the bearing structure including the radial bearing 38 and the thrust bearing 57 can be reduced, and the disk rotation drive device can be made thin.

According to the disk drive device constructed as described above, the turntable-cum-boss member 42 is formed by integrally molding the boss portion 43 and the turntable portion 44, and the turntable portion is also formed. Since the rotor 46 is attached to the outer peripheral portion of the rotor 44,
Since the distance between the turntable portion 44 and the turntable portion 44 (the distance S in the conventional example shown in FIG. 4) is eliminated, the height H ₂ of the turntable portion 44 is higher than the height H ₁ in the conventional example shown in FIG. It will be significantly lower. Further, since the boss portion 43 is arranged in the central space formed by the central opening of the yoke 47 and the central opening of the ring-shaped magnet 14, the turntable portion 44, the boss portion 43, and the rotor 46.
The height of the composite structure consisting of is also significantly reduced. Moreover,
By attaching the rotor 46 to the outer peripheral portion of the turntable portion 44, the space 50 is secured below the turntable portion 44, so that the drive pin support lever 52 can be arranged in the space 50. Therefore, the height H ₂ of the turntable portion 44 does not increase due to the lever 52.

Further, the boss member 42, in which the boss portion 43 and the turntable portion 44 are integrally formed, is fixed to the motor shaft 40 by press fitting or adhesion without increasing the height of the entire disk rotation driving device. Boss part 43
It is possible to make the thickness T ₁ of the film sufficiently thick. Therefore, the horizontal accuracy of the boss member 42 with respect to the motor shaft 40 can be easily obtained, so that the rotor 46 and the turntable portion 44 can be obtained.
It is possible to prevent the surface wobbling.

By the way, in the disk rotation driving device of this embodiment, the thrust bearing 57 having a large diameter D at its shaft supporting portion axially supports the turntable / boss member 42 in the thrust direction. Therefore, the tilt of the motor shaft 40 is prevented by the thrust bearing 57, and the lateral stability of the motor shaft 20 with respect to the chassis 7 is stabilized by the radial bearing 38.
The rattling of the motor shaft 40 is suppressed.

That is, as described in the conventional example shown in FIG. 4, the bearing structure including the pair of upper and lower radial bearings 9 and 10 has a gap L ₁ between the radial bearings 9 and 10 when the motor 1 is made thin. Becomes shorter. For this reason, the rattling of the motor shaft 2 becomes large, and the disc 26
Since the position of the head with respect to is unstable, tracking accuracy deteriorates. In this case, the eccentricity between the motor shaft 2 and the radial bearing 9 and the gap between the motor shaft 2 and the radial bearing 10 cause the motor shaft 2 to swing around the point A and rattle, so that the swing at the point B is L ₁ and L ₂ . Determined by the length ratio. Conventionally, as a measure against this type of shaft runout, it is common to provide a preload mechanism by using a rolling bearing as the bearing and forming the housing so that the number of press-fitted points with respect to the motor shaft 2 is as large as possible. This is difficult because it has space problems and is expensive.

However, in this embodiment, since the thrust bearing 57 having a large diameter D at its shaft support portion is used, the length L ₁ corresponds to the diameter D. The value of the diameter D can be increased to H ₂ or more even if the height of the motor 35 becomes low.
Even if the motor 35 is an eccentric motor, the vibration of the motor shaft 40 can be reduced. Then, as compared with the case where the preload mechanism is provided by forming the housing by using a pair of upper and lower radial bearings, it is possible to configure an effective bearing structure in which the component accuracy is reduced and the cost is low. Moreover, since the bearing 57 is a thrust bearing,
It can be easily incorporated into the motor 35 and can be automatically assembled.

The embodiment of the present invention has been described above.
The present invention is not limited to the embodiments described above, and various effective changes can be made based on the technical idea of the present invention.

For example, in the above-mentioned embodiment, the turntable for magnet chucking is shown, but a chucking structure in which the center core of the disc is press-fitted on the upper part of the motor shaft, or the center part of the disc is clamped on the turntable. A chucking structure for crimping may be used.

Further, the present invention is not limited to the micro-floppy disc rotation drive device, but can be applied to various disc rotation drive devices in which various discs are mounted on a turntable and driven to rotate.

[0030]

According to the present invention, the rotary shaft to which the turntable is attached is supported by the radial bearing in the radial direction and in the thrust direction by the thrust bearing, and the thrust bearing is the shaft of the rotary shaft. When viewed from the axial direction, it is arranged at a position outside the radial bearing between the flange-shaped member and the chassis. Therefore, the rotating shaft can be reliably supported in both the radial direction and the thrust direction, so that the rotation of the turntable can be stabilized, and thus the recording / reproducing characteristics of the disk can be improved.

Further, the thrust bearing has the axial center of the rotary shaft as seen from a direction orthogonal to the axial direction of the outer position of the radial bearing between the flange-shaped member and the chassis when viewed from the axial direction of the rotary shaft. At least partially overlaps the thrust bearing in the direction. Therefore, although the rotating shaft can be reliably supported in both the radial direction and the thrust direction, the height of the bearing structure including the radial bearing and the thrust bearing is reduced to make the disk rotation drive device thinner. be able to.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a main part in a longitudinal sectional state in an embodiment in which the present invention is applied to a micro-floppy disk rotation driving device.

FIG. 2 is a longitudinal sectional view of a main part of the micro floppy disk rotation drive device shown in FIG. 1 with a disk mounted on a turntable.

FIG. 3 is an enlarged vertical sectional view of a part of the micro-floppy disk rotation drive device shown in FIG. 2 with a disk and a drive pin support lever removed.

FIG. 4 is a longitudinal sectional view showing a state in which a disk is mounted on a turntable of a conventional microproppy disk rotation driving device.

[Explanation of symbols]

7 Chassis 26 Disk 35 Motor 38 Radial Bearing 40 Motor Shaft (Rotating Shaft) 42 Turntable / Boss Member (Flange Member) 44 Turntable Part 57 Thrust Bearing

Claims (1)

[Claims] 1. A disk rotation drive device comprising a rotation shaft rotatably supported by a chassis and rotationally driven by a motor, and a turntable attached to the rotation shaft for rotationally driving a disk. A flange-shaped member attached to the shaft; a radial bearing that supports the rotary shaft in a radial direction with respect to the chassis; and a rotary shaft that supports the rotary shaft by rotatably supporting the flange-shaped member on the chassis. A thrust bearing supported in the thrust direction with respect to, the thrust bearing, when viewed from the axial direction of the rotating shaft,
The rotary shaft is configured to be arranged at an outer position of the radial bearing between the flange-shaped member and the chassis, and the radial bearing is viewed from a direction orthogonal to the axial direction of the rotary shaft. Disk drive device configured to at least partially overlap the thrust bearing in the axial direction of the disk.