JPH0222869Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a drive shaft of a disk rotation drive device that is attached to the rotational center of a sheet-like magnetic disk in the form of a disk, for example, and that rotates the magnetic disk. The present invention relates to a center core of a magnetic disk device that is inserted into and engaged with the center core of a magnetic disk device.

[Conventional technology]

Conventionally, information signals such as still image information are recorded on a disk-shaped sheet-like magnetic disk that is rotated by a disk rotation drive device, or magnetic recording is such that the recorded information signals are read and reproduced. A playback device has been proposed.

As shown in FIG.
It is housed in a jacket 102 consisting of 2a and 102b, and is mounted in the magnetic recording/reproducing apparatus while being housed in this jacket 102. and,
At the center of rotation of the magnetic disk 101 is a drive shaft 10 of a disk rotation drive device 103 provided on the side of the magnetic recording/reproducing device when the magnetic disk 101 is installed in the device.
A center core 105 is attached to which 4 is inserted and engaged. The center core 105 includes a positioning member 106 made of an annular magnetic metal, to which the magnetic disk 101 is bonded and fixed;
Core body 1 integrally formed of synthetic resin fixed to inner hole 107 of positioning member 106
It consists of 08.

A shaft insertion hole 109 into which the drive shaft 104 is inserted and engaged is formed in the center of the core body 108 . On the inner peripheral side of this shaft insertion hole 109, as shown in FIG.
0 is formed. These positioning surfaces 110,
110 are formed so as to be inclined to each other so as to form a wedge shape. Further, at a position facing the pair of positioning surfaces 110, 110 of the core body 108,
A slotted groove 112 is bored in a substantially U-shape, and a pressing piece 111 is formed.

A pair of positioning surfaces 110, 110 as described above.
By forming the pressing piece 111 opposite to these positioning surfaces 110, 110, the shaft insertion hole 1 is
When the drive shaft 104 is inserted into and engaged with the positioning surface 11, the pressing piece 111 is elastically displaced and the positioning surface 11
0 and 110 are brought into pressure contact with the outer peripheral surface of the drive shaft 104. As a result, the center core 105 presses and holds the drive shaft 104, and the center core 105
The magnetic disk 101, which has a fixed rotation center, can rotate integrally with the drive shaft 104 while maintaining a constant center of rotation.

[The problem that the idea aims to solve]

By the way, the core body 108 is formed of a synthetic resin molded body, and the pressing piece 1 is integrally formed with the core body 108.
In the case of the center core 105 formed with 11,
In order to guarantee the mechanical strength of the pressing piece 111,
A pair of positioning surfaces 110, 110 are connected to the drive shaft 104.
It is extremely difficult to form a structure so as to obtain sufficient elastic displacement force to press and support it. That is, in order to guarantee the connection strength of the pressing piece 111 to the core body 108 and maintaining the mechanical strength of the pressing piece 111 itself, it is necessary to increase the thickness of the pressing piece 111. As a result, the spring constant as the elastic displacement force of the pressing piece 111 has become unnecessarily large.

If the spring constant of the pressing piece 111 becomes unnecessarily large as described above, a large force will be required to insert and engage the center core 105 into the drive shaft 104, and the drive shaft 104 of the magnetic disk 101 will
It becomes impossible to perform a smooth installation operation. If the diameter of the shaft insertion hole 109 surrounded by the pair of positioning surfaces 110, 110 and the pressing piece 111 cannot be formed to a predetermined size, especially if the diameter of the shaft insertion hole 109 is not the same as that of the drive shaft 104. In cases where the diameter is extremely smaller than the diameter,
The pressing displacement force by the pressing piece 111 changes greatly, and not only is it impossible to smoothly insert the driving shaft 104 into the shaft insertion hole 109, but also the center core
05 is not horizontally inserted and engaged with the drive shaft 104, but is tilted, and the axis of rotation of the magnetic disk 101 is inclined with respect to the axis of the drive shaft 104. If the axis of rotation of the magnetic disk 101 is tilted in this manner, it becomes impossible to perform stable rotation of the magnetic disk 101.

However, the core body 10 including the pressing piece 111
8 is integrally molded from synthetic resin, so it is difficult to form the thin pressing piece 111 with high dimensional accuracy.

Furthermore, since the pressing piece 111 is made of synthetic resin, when it is used in an environment of 65° C. for 15 hours, for example, the internal stress generated by the spring force of the pressing piece 111 is relaxed, and the Pressing piece 11
The spring force of No. 1 will decrease. As described above, when the spring force of the pressing piece 111 decreases, the gripping state of the driving shaft 104 by the pressing piece 111 becomes unstable, and when the magnetic disk 101 is rotating, the center of rotation of the magnetic disk 101 is Drive shaft 10
There is a risk of eccentricity with respect to the axis of No. 4.

Therefore, the present invention aims to solve the problems that arise from integrally molding the core body from synthetic resin, and even when the core body is integrally molded from synthetic resin, it is possible to obtain the necessary and sufficient pressing and clamping force against the drive shaft. is,
Another object of the present invention is to provide a center core in a magnetic disk device that can be smoothly inserted into and engaged with the drive shaft and that prevents the center of rotation of the magnetic disk from being eccentric with respect to the axis of the drive shaft. It is what was done.

[Means to solve the problem]

Therefore, in order to achieve the above-mentioned object, the present invention includes a positioning member made of an annular magnetic metal to which a magnetic disk is fixed, and a pair of positioning surfaces and a pressing piece that are fixed to the inner hole of the positioning member. In the center core of a magnetic disk device, the core body is integrally molded with synthetic resin and has a shaft insertion hole in a space surrounded by the pair of positioning surfaces and the pressing piece. , is formed continuously with the pair of positioning surfaces with a predetermined width in the axial direction of the drive shaft to be inserted into the shaft insertion hole, and its main body is movable with respect to the axis of the drive shaft. The notch portion is provided at least in a portion between the main body portion and the positioning surface.

[Effect]

In the present invention, a drive shaft of a disk rotation drive device is inserted into and engaged with a shaft insertion hole surrounded by a pair of positioning surfaces and a pressing piece, and the pair of positioning surfaces is inserted and engaged using the elastic displacement force of the pressing piece. Pressed against the outer peripheral surface of the drive shaft.

Furthermore, when the drive shaft is inserted into the shaft insertion hole, the pressing piece is tilted and displaced not only in the radial direction of the core body but also in the axial direction.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

The magnetic disk 2 to which the center core 1 according to the present invention is attached is also housed in a jacket 3 consisting of upper and lower halves 3a and 3b, as shown in FIG. 3, similarly to the conventional disk. Both axial ends 1a and 1b of the center core 1 face openings 3a and 3b formed in the center of the jacket 3.

The center core 1 includes a positioning member 4 formed of an annular magnetic metal to which the magnetic disk 2 is bonded and fixed on one surface, and a synthetic resin fixed to the inner hole of the positioning member 4, which are integrally molded. The core body 6 is formed by

The other surface of the positioning member 4 opposite to the one surface to which the magnetic disk 2 is bonded is formed parallel to the magnetic recording surface 2a of the magnetic disk 2,
It serves as a position reference surface supported by an annular positioning rib 9 protruding from a rotary table 8 provided on the drive shaft 7 side of the disk rotation drive device. That is, in the magnetic disk 2, the center core 1 is supported by the tip of the positioning rib 6, so that the magnetic recording surface 2a is in a stable state with respect to the magnetic head disposed on the magnetic recording/reproducing apparatus side. It is now possible to contact.

On the other hand, the core body 6 is connected to the positioning member 4.
It is integrally formed by outsert molding synthetic resin around the circumference of the inner hole 5, and a shaft insertion hole 10 into which the drive shaft 7 is inserted and engaged is formed in the center thereof. On the inner peripheral side of this shaft insertion hole 10,
As shown in FIG. 4, a pair of positioning surfaces 11, 11 are formed similarly to the conventional core body.
These positioning surfaces 11, 11 are formed so as to be inclined to each other so as to form a wedge shape. Further, at a position of the core body 6 facing the pair of positioning surfaces 11, 11, a slotted groove 12 is bored in a substantially U-shape to form a pressing piece 13. That is, the shaft insertion hole 101 is configured to have a space surrounded by the pair of positioning surfaces 11, 11 and the pressing piece 13 in the core body 6.

Incidentally, the slotted groove 12 is bored until both ends thereof reach the respective ends of the positioning surfaces 11, 11. Therefore, the pressing piece 13 is formed so that both ends thereof are connected to the respective ends of the positioning surfaces 11, 11, respectively. Further, since the slotted groove 12 is formed so as to communicate with the core body 6 in the axial direction, the continuous portion 13a of the pressing piece 13 with respect to each positioning surface 11,
13b is formed to have the same width as the thickness of the core body 6.

The upper end side of the main body part 13c that presses and supports the drive shaft 7 formed in the center of the pressing piece 13 and the continuous part 13 with respect to the positioning surfaces 11, 11 are provided.
Concave notches 14, 15, and 16 are formed on the lower end sides near a and 13b, respectively, and serve as width narrowing portions. In this way, each positioning surface 1
By providing narrow notches 15 and 16 in the vicinity of the continuous portions 13a and 13b with respect to the shaft insertion holes 10 and 11, the pressing piece 13 can insert the drive shaft 7 into the shaft insertion hole 10.
When the notches 15,
16, the narrowed portion is used as a fulcrum to be twisted and elastically displaced in the direction of arrow A in FIG. That is, when the pressing piece 13 is elastically displaced to expand the diameter of the shaft insertion hole 10, a spring force is generated due to torsional stress, and the spring constant thereof becomes small.

Therefore, even if the diameter of the shaft insertion hole 10 is formed to be sufficiently smaller than the shaft diameter of the drive shaft 7, the drive shaft 7 can be smoothly inserted into and engaged with the shaft insertion hole 10. By stably pressing and supporting the outer circumferential surface of the drive shaft 7 horizontally by the pressing piece 13, the pair of positioning surfaces 11, 11 can be reliably brought into pressure contact with the outer circumferential surface of the drive shaft 7. . As a result, the magnetic disk 2 is mounted without eccentrically centering its rotation center with respect to the axis of the drive shaft 7.

Moreover, since the internal stress of the pressing piece 13 can be reduced by twisting the pressing piece 13, the stress relaxation can be reduced. Therefore, since the spring force of the pressing piece 13 can be maintained at a predetermined value, the driving shaft 7 can be inserted into the shaft insertion hole 1.
0, and eccentricity of the rotation center of the magnetic disk 2 with respect to the axis of the drive shaft 7 can be reliably prevented.

In the embodiment described above, the notches 14 and 15,
16 indicates the upper end side of the main body portion 13c of the continuous portion 13 and the continuous portions 13a, 1 with respect to the positioning surfaces 11, 11.
3b, as shown in FIG.
Concave notches 20 and 2 are provided on the upper end side of the vicinity.
1, 22, and 23 may be provided.

In this way, each notch 20, 21 and 22, 23
Even in the case where the magnetic disk 2
can be mounted horizontally to the drive shaft 7 without making the center of rotation eccentric.

Furthermore, since the stress relaxation of the pressing piece 13 can be reduced, the drive shaft 7 can be reliably pressed and supported within the shaft insertion hole 10, and the axis of the drive shaft 7, which is the center of rotation of the rotating magnetic disk 2, can be Eccentricity can be reliably prevented.

In addition, in the present invention, when the drive shaft 7 is inserted into the shaft insertion hole 10, the pressing piece 13 touches the positioning surfaces 11, 11.
The position of the notch is not limited to the above embodiments as long as it can be twisted using the continuous portion side as a fulcrum.

[Effect of idea]

As described above, in the present invention, the drive shaft of the disk rotation drive device is inserted into and engaged with the shaft insertion hole surrounded by the pair of positioning surfaces and the pressing piece, and the elastic displacement force of the pressing piece is utilized to The pair of positioning surfaces are brought into pressure contact with the outer peripheral surface of the drive shaft, and when the drive shaft is inserted into the shaft insertion hole, the pressing piece is tilted and displaced not only in the radial direction of the core body but also in the axial direction. Therefore, even when the core body is integrally molded from synthetic resin, the necessary and sufficient pressing and clamping force against the drive shaft can be obtained, and the insertion and engagement operation with respect to the drive shaft can be performed smoothly. It is possible to provide a center core in a magnetic disk device in which the center of rotation of the magnetic disk device is not eccentric with respect to the axis of the drive shaft.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of a conventional magnetic disk device, and FIG. 2 is a plan view showing a center core in the magnetic disk device. FIG. 3 is a sectional view showing the main parts of a magnetic disk device to which a center core according to the present invention is attached, FIG. 4 is a partially cutaway perspective view of the center core, and FIG. FIG. 7 is a partially cutaway perspective view showing another example of such a center core. 1...Center core, 2...Magnetic disk, 4
... positioning member, 5 ... inner hole of positioning member,
6... Core body, 7... Drive shaft, 10... Shaft insertion hole, 11... Positioning surface, 13... Pressing piece, 13
c...Main part of the pressing piece, 15, 16...Notch part.

Claims (1)

[Claims for Utility Model Registration] A positioning member made of an annular magnetic metal and to which a magnetic disk is fixed, and a pair of positioning surfaces and a pressing piece fixed to an inner hole of the positioning member, In the center core of a magnetic disk device, the core body is integrally molded from synthetic resin, and the space surrounded by the positioning surface and the pressing piece is the shaft insertion hole. At least the main body includes a notch portion that is formed continuously with the pair of positioning surfaces with a predetermined width in the axial direction of the drive shaft, and that allows the main body portion to be displaced relative to the axis of the drive shaft. A center core in a magnetic disk device, characterized in that the center core is provided in a portion between the positioning surface and the positioning surface.