JPH0547100A - Flexible disk - Google Patents

Abstract

PURPOSE:To provide the flexible disk device with a bearing part capable of supporting the rotation with high accuracy in spite of its thin structure. CONSTITUTION:An axis 2 is vertically fixed to a substrate 1. A thrust member 4 is intervened between its bearing part, and thrust load is supported by covering a cylindrical medium rotational axis 3 forming the closed bottom part. The radial load is supported by the outer peripheral surface of the axis 2 and the inner peripheral surface of the outer axis 3, and a hub 5 is fixed to the outer peripheral surface of the medium rotational axis 3, constituting a rotor 6 and a rotor part. In the substrate 1, a winding coil 8 is arranged. The rotor part is rotated by applying electric current. The thrust member shall be part of the medium rotational axis 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible disk device used as an external storage device in a computer or the like.

[0002]

2. Description of the Related Art A conventional flexible disk device (hereinafter, simply referred to as a device) has a medium rotating shaft for rotating a recording medium press-fitted onto a bearing boss such as a ball bearing or an oil-impregnated metal bearing, or fixed by adhesion to support rotation. By doing so, the flexible disk (hereinafter referred to as disk) on the rotor fixed to the medium rotation shaft is rotated.

In the ball bearing or the oil-impregnated metal bearing having the above-mentioned structure, in the radial direction (the direction perpendicular to the axis), the inner ring of the ball bearing and the inner peripheral surface of the oil-impregnated metal bearing support the medium rotating shaft. However, the load in the thrust direction (axial direction) is supported by the shaft and the bearing inner ring surface. There is also a structure in which a plurality of washers are inserted between a hub fixed to a shaft and a ball bearing or an end surface of an oil-impregnated metal to support the medium rotation shaft.

[0004]

However, in the above-mentioned conventional apparatus, when the apparatus is made thin, the length of the bearing portion supporting the medium rotating shaft becomes short in proportion to the thickness of the apparatus, As a result, the clearance between the media rotation shaft and the inner ring of the bearing and the clearance in the radial direction of the bearing increase the runout of the media rotation shaft, lowering the centering accuracy of the recording media, and failing to function as a device. There was a problem that it was impossible to make it thinner.

When the oil-impregnated metal bearing is made thinner, the bearing length becomes shorter and
Due to the bearing clearance, there is a problem that the lateral pressure increases due to the deviation of the shaft, resulting in a large bearing loss and a decrease in durability.

In view of the above, the present invention provides a flexible disk device which has a simple structure and is durable because the bearing length is ensured even when the device is made thin and therefore the rotation of the medium rotation shaft can be supported with high accuracy. To aim.

[0007]

According to the present invention, a thrust member is arranged between a shaft top of a shaft fixed vertically to a substrate and a bottom provided on a cylindrical body forming a medium rotation shaft, or the above-mentioned cylinder. The thrust load is supported by forming the portion of the body facing the shaft top with a thrust member, and the radial load is applied over almost the entire length of the medium rotation shaft (excluding the thickness of the bottom of the medium rotation shaft). Is supported so that the bearing length is secured and the medium rotation shaft is rotated with high accuracy.

The hub fixing position on the medium rotation shaft is set within the range of the bearing length to prevent uneven contact and suppress surface wobbling to reduce lateral pressure, and the shaft apex is formed into a spherical surface or a flat surface. A ceramic or plastic thrust member is combined with the shape of the shaft top.

[0009]

According to the present invention, the thrust member arranged between the top of the shaft and the bottom of the cylindrical body forming the medium rotation shaft enables thrust support with a simple structure.

Further, since the thrust member is arranged between the bottom of the medium rotating shaft and the shaft apex of the shaft, or the portion corresponding to the shaft apex of the shaft of the medium rotating shaft is formed by the thrust member. The friction of the thrust support of the medium rotating shaft is small and the bearing loss is small.

Further, since it is possible to radially support the medium rotating shaft over substantially the entire length (excluding the thickness of the bottom portion), the medium rotating shaft can rotate with high precision.

Further, since the bearing portion is constituted by the cylindrical inner peripheral surface of the medium rotating shaft, the whole constitution is simplified.

Further, since the fixed portion between the medium rotating shaft and the hub can be provided with a length on the outer peripheral surface of the medium rotating shaft which can ensure sufficient accuracy, the runout of the rotor can be reduced and the rotating accuracy of the motor can be improved. can do.

Further, by combining the shaft member with a spherical surface or a flat surface and combining the thrust member with ceramics or plastics, a durable flexible disk device with low friction of thrust support and low bearing loss can be realized.

[0015]

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

FIG. 1 is a sectional view showing the structure of a motor section of a flexible disk device according to a first embodiment of the present invention.
The base end of the shaft 2 is vertically fixed to the substrate 1, and the medium rotation shaft 3
Is formed in a cylindrical shape having an opening and a bottom formed by closing the other end, envelops the shaft 2, and disposes a thrust member 4 between the shaft top of the shaft 2 and the bottom. A thrust load is supported by the shaft 2 via the shaft 2.

On the other hand, the spherical outer peripheral surface of the medium rotation shaft 3 guides the center hole (not shown) of the disc when the disc is mounted. The hub 5 is fixed to the outer peripheral surface of the bottom portion of the medium rotating shaft 3 by press fitting or the like, and the inner peripheral hole of the rotor 6 is narrowed and fixed at the outer peripheral step portion of the hub 5, and the medium rotating shaft 3 and the rotor 6 are integrated. It is rotatable. A magnet 7 is attached to the upper surface of the rotor 6 by adhesion or the like, and attracts and rotates the center core of the driven disk. Further, a magnet 9 is similarly attached to the inner surface of the rotor 6 by adhesion or the like, and constitutes the rotor of the motor section.

On the other hand, the substrate 1 itself constitutes a circuit substrate or is provided with a thin circuit substrate (not shown), and a plurality of winding coils 8 are arranged so as to face the magnets 9 of the rotor 6. And constitutes the stator of the motor section.
Therefore, when the winding coil 8 is energized, the magnet 9 receives a rotational force and the rotor 6 rotates. At this time, the outer peripheral surface of the shaft 2 and the inner peripheral surface of the medium rotating shaft 3 constitute a radial bearing that supports a force from a direction perpendicular to the shaft 2.

Since the material of the substrate 1 is made of iron plate, silicon steel plate or the like in order to improve the magnetic efficiency of the motor part, an attractive force is generated between the substrate 9 and the magnet 9, and the bottom of the medium rotating shaft 3 is It is pressed against the thrust member 4 side for bearing the load in the direction of the shaft 2.

FIG. 2 is a detailed sectional view showing the bearing portion of the above-mentioned first embodiment of the present invention. Since the base end portion 21 of the shaft 2 is fixed to the substrate 1, a seat portion is formed so as to be one step thinner than the outer peripheral surface 22 of the shaft 2, and the seat portion is crushed and expanded by squeezing or the like.
It is fixed to the hole provided in the substrate 1. At the same time, the seat portion vertically fixes the shaft 2 to the substrate 1. The shaft top of the shaft 2 is formed into a spherical surface 23 and is in contact with the thrust member 4. The medium rotation shaft 3 includes an inner peripheral surface 31, a bottom portion 32, and an inner peripheral surface 31.
It has a cylindrical shape having an outer peripheral surface 34 on which an escape portion 33 for finishing processing is formed.

The outer peripheral surface 22 of the shaft 2 and the inner peripheral surface 31 of the medium rotating shaft 3
A slight clearance is provided in the shaft, and constitutes a radial bearing portion against a load from the lateral direction in the figure, and the spherical surface 23 of the shaft 2
Since the bottom portion 32 of the medium rotating shaft 3 supports the load in the thrust direction via the thrust member 4, the cylindrical inner peripheral surface 31 of the medium rotating shaft 3 constitutes a bearing portion. A lubricant is injected into the bearing portion having the above structure.

The hub 5 is constructed by providing an inner peripheral hole 51, a rotor core fixing portion 52, and a center core receiving surface 53 of a floppy disk for driving the inner peripheral hole 51. The inner peripheral hole 51 is press-fitted and fixed to the outer peripheral surface 34 of the medium rotating shaft 3 by press fitting or the like. Has been done. The inner peripheral hole 51 of the hub 5 is set long enough to reduce the surface runout of the rotor 6, but is within the range of the length of the outer peripheral surface 22 that supports the radial load of the shaft 2.

In the above embodiment, when the winding coil 8 (FIG. 1) is energized, a rotating force is generated in the magnet 9, and the rotor 6, the hub 5 and the medium rotating shaft 3 rotate integrally.

On the other hand, since the bearing portion formed on the inner peripheral surface 31 of the medium rotating shaft 3 and the outer peripheral surface 22 of the shaft 2 is long regardless of the thinning of the device, the medium rotating shaft 3 is prevented from swinging and is highly accurately radial. Supports directional loads.

Further, since the positional relationship between the radial load support and the hub 5 is within the range of the length of the shaft 2 for radial support, there is no one-sided contact between the shaft 2, the medium rotation shaft 3 and the radial clearance, and the runout is suppressed. At the same time, the lateral pressure decreases,
Low friction rotation can be performed.

The shaft 2 made of stainless steel or bearing steel
The smooth spherical surface 23 and the ceramic thrust member 4 suppress the load in the thrust direction with low friction, and maintain the smooth rotation of the medium rotation shaft 3.

As described above, according to the first embodiment described above, the bearing portion is formed on the inner peripheral surface of the medium rotating shaft 3 to support the load in the radial direction and the thrust direction. As a result, the bearing length does not become too short and the bearing length is secured, so that the rotation of the medium rotation shaft 3 can be supported with high accuracy.

Further, since the thrust member 4 is arranged on the spherical surface 23 of the shaft 2 and the bottom portion 32 of the medium rotating shaft 3, the structure is simplified and the assembling property is improved.

Further, since the fixing portion of the hub 5 is formed long on the outer peripheral surface 34 of the medium rotating shaft 3, the concentricity of the hub 5 and the medium rotating shaft 3 and the degree of suppression of runout are enhanced, and therefore the rotor 6 of the rotor 6 is prevented. While the run-out and eccentricity are eliminated and the characteristics of the motor are improved, the hub 5 can be positioned within the length of the outer peripheral surface 22 of the shaft 2 to support the radial load with low friction by eliminating one-sided contact. It has the effect of increasing durability.

Further, the spherical surface 23 of the shaft 2 and the ceramic thrust member 4 have an effect of excellent durability such as low friction and support of a load in the thrust direction.

FIG. 3 is a sectional view of the essential parts showing the second embodiment. In FIG. 3, the shaft 2a is fixed vertically to the substrate 1,
It supports the radial direction and the thrust direction of the medium rotation shaft 3. The end surface of the shaft apex that receives the thrust load of the shaft 2a is formed into a flat surface 23a, and the thrust member 4b formed of plastics is interposed between the shaft 2a and the inner bottom portion of the medium rotation shaft 3.
Abut. By forming the thrust member 4b from a plastic having a good sliding property, such as polyamide containing carbon particles, it is possible to reduce the friction coefficient and to support the thrust load with no lubricant.

As described above, according to the second embodiment, the shaft 2
The shaft top end surface of a is a flat surface 23a, and the surface pressure of the thrust member 4b is reduced to eliminate the creep of the thrust member 4b so that plastics can be used, and at the same time, the thrust is supported by the plastics having a low friction coefficient to provide lubrication. The thrust bearing portion of the medium rotating shaft 3 having excellent durability can be configured without using the agent.

FIG. 4 is a sectional view of the essential parts showing the third embodiment. In FIG. 4, the shaft 2 is vertically fixed to the substrate 1 and supports the rotation of the medium rotation shaft 3a. The medium rotation shaft 3a does not have a bottom portion whose both ends are open and closed. Medium rotating shaft 3a
The inner peripheral surface of is a short inner peripheral surface 31b that fixes the thrust member 4a to the inner peripheral surface 31a that constitutes the radial bearing portion, and the groove portion between them.
It has 33a and constitutes the inner peripheral surface.

The thrust member 4a has a flat surface portion 41 and a spherical surface portion 4
2 and a ventilation hole 43, which is made of metal or ceramics and is fixed to the inner peripheral surface 31b of the medium rotating shaft 3a by pressing the flat portion 41 toward the inner peripheral surface side.
It abuts the spherical surface 23 to support the thrust load.

On the other hand, the spherical surface portion 42 of the thrust member 4a forms an outer peripheral surface with a curvature continuing to the outer peripheral surface of the medium rotating shaft 3a and guides the center hole of the disk. Also, the ventilation holes 43
Is for releasing the internal pressure when assembling the medium rotating shaft 3a to the shaft 2 and facilitating the assembling.
The same effect can be obtained even if it is provided in a.

The operation of the embodiment shown in FIG. 4 is similar to that of the first embodiment, and the load in the radial direction and the thrust direction is applied to the medium rotating shaft 3.
It is rotatably supported by the bearing composed of the inner peripheral surface of a. On the other hand, since the thrust member 4a is fixed to the medium rotation shaft 3a, the thrust member 4a rotates integrally and is in contact with the spherical surface 23 of the shaft 2.
Support with even lower friction.

Further, since both ends of the inner peripheral surface of the medium rotating shaft 3a are open, finishing of the inner peripheral surface is easy, so that the finishing accuracy of the processing accuracy and surface roughness is improved, and the shaft 2 and the medium are improved. Friction of the radial bearing portion composed of the rotating shaft 3a is reduced, and smooth rotation with a small bearing loss is maintained.

The groove portion 33a of the medium rotating shaft 3a serves to absorb the deformation of the inner peripheral surface due to the pressure when the thrust member 4a is press-fitted and the like and to maintain the accuracy of the inner peripheral surface 31a.

As described above, according to the third embodiment,
In addition to the effects of the first embodiment, the medium rotating shaft 3a
Since both ends are open, the workability is improved, the accuracy and surface roughness of the inner peripheral surface are improved, and low friction and high durability can be realized.

Further, since the thrust member 4a is fixed to the medium rotating shaft 3a and integrally rotated, the thrust load supporting portion also has low friction, and a bearing portion having a small bearing loss and excellent durability is formed. Furthermore, since the thrust member 4a is fixed to the medium rotating shaft 3a, the structure is simple and the assembling property is improved.
When the thrust member is formed by firing or the like, there are many effects such as easy formation of ventilation holes.

[0041]

As described above, in the flexible disk device of the present invention, the shaft fixed to the substrate is wrapped by the inner peripheral surface of the cylindrical medium rotating shaft to form the bearing portion. Therefore, even if the apparatus is thinned, a bearing portion having a length close to the entire length of the medium rotation shaft is formed, and therefore, it is possible to support the highly accurate rotation of the rotor.

Further, since the thrust member is arranged between the shaft apex of the shaft or formed as a part of the medium rotating shaft to support the thrust load, the structure is simplified and the assemblability is improved. Be done.

Further, since the hub is fixed to the outer peripheral portion of the medium rotation shaft by press fitting, the hub does not have a bearing on the outer peripheral portion. Therefore, the length of the press fitting portion is sufficiently secured, and the surface wobbling of the rotor, It has the effect of eliminating eccentricity and can be expected to have a great effect when used in an external storage device of a computer.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a motor unit of a flexible disk device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing details of a bearing portion of the motor portion shown in FIG.

FIG. 3 is a sectional view showing details of a bearing portion of a motor portion in a second embodiment of the present invention.

FIG. 4 is a sectional view showing details of a bearing portion of a motor portion according to a third embodiment of the present invention.

[Explanation of Codes] 1 ... Substrate, 2, 2a ... Shaft, 3, 3a ... Medium rotation shaft,
4, 4a, 4b ... Thrust member, 5 ... Hub, 6 ... Rotor, 7, 9 ... Magnet, 8 ... Winding coil, 21 ... Base end part, 22, 34 ... Outer peripheral surface, 23 ... Spherical surface, 23a ... Plane, 3
1, 31a, 31b ... Inner peripheral surface, 32 ... Bottom part, 33 ... Relief part, 3
3a ... Groove portion, 41 ... Flat portion, 42 ... Spherical portion, 43 ... Vent hole,
51 ... Inner hole, 52 ... Rotor fixing part, 53 ... Center core receiving surface.

Claims (10)

[Claims] 1. A shaft for fixing a motor portion of a flexible disk device vertically to a substrate, a medium rotating shaft formed by capping a cylindrical body having a closed bottom portion on the shaft, and a shaft for rotating the shaft. The thrust member arranged between the shaft top and the bottom of the cylindrical body forming the medium rotation axis, the hub having the outer peripheral stepped portion fixed to the outer periphery of the cylindrical portion, and fixed to the outer peripheral stepped portion. The above-mentioned shaft top portion supports the thrust load to the medium rotating shaft via the thrust member, and the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical body of the medium rotating shaft. A flexible disk device, wherein the flexible disk device is configured to support a radial load on the medium rotation shaft. 2. The flexible disk device according to claim 1, wherein the shaft top is formed into a spherical surface, and the thrust member is formed of ceramics. 3. The flexible disk device according to claim 1, wherein the shaft top is formed in a flat surface, and the thrust member is formed of plastics. 4. The hub is fixed to the medium rotating shaft within the axial length of a radial load support portion formed by the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical body of the medium rotating shaft. The flexible disk device according to claim 1, which is characterized in that. 5. The flexible disk device according to claim 1, wherein the medium rotation shaft and the hub are integrally processed. 6. A bottom portion is formed by complementing and adhering a motor portion of a flexible disk device to a shaft vertically fixed to a substrate and one opening portion of a tubular body having both ends opened by using a thrust member. A medium rotating shaft formed by crowning a cylindrical body on the shaft; a hub provided with an outer peripheral step portion fixed to the outer periphery of the medium rotating shaft; and a rotor fixed to the outer peripheral step portion, The shaft apex of the shaft supports the thrust load of the medium rotating shaft via the thrust member of the opening, and the outer peripheral surface of the shaft and the cylindrical inner peripheral surface of the medium rotating shaft, A flexible disk device configured to support a radial load of a medium rotation shaft. 7. The flexible disk device according to claim 6, wherein the shaft top is formed into a spherical surface, and the thrust member is formed of ceramics. 8. The flexible disk device according to claim 6, wherein the shaft top portion is formed in a flat surface, and the thrust member is formed of plastics. 9. The hub is fixed to the medium rotating shaft within the axial length of a radial load supporting portion formed by the outer peripheral surface of the shaft and the inner peripheral surface of the cylindrical body of the medium rotating shaft. The flexible disk device according to claim 6, which is characterized in that. 10. The flexible disk device according to claim 6, wherein the medium rotation shaft and the hub are integrally processed.