JPH0341320Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The invention is applicable to detecting the rotational position of, for example, magnetic disks, floppy disks for electronic cameras, CDs, VDs (laser disks, VHD), and other rotating driven objects. related to a device for

[Conventional technology]

A magnetic disk is a typical example of a rotationally driven body. In recent years, recording and reproducing devices using small magnetic disks and the like as recording media have come to be widely used as information recording or image recording devices for small computers.

FIG. 1 is a perspective view showing a part of a conventional magnetic disk recording/reproducing apparatus of this type. First, the configuration of the magnetic disk pack 100 will be explained. A magnetic disk 101, which is made of a flexible polyester base or the like coated with magnetic recording medium components, has a center core 1.
02, and is rotatably housed in a jacket 103 made of rigid plastic. In addition, disk 101, center core 10
2 is rotatable within the jacket 103. In the center of both the front and back walls of the jacket 103,
Hole 1 for chucking center core 102
04, 105, and holes 106, 107 for inserting a magnetic head or the like. Above hole 1
06,107 is shutter 10 when not in use.
8 and locked by a locking device (not shown). In this way, dust and the like are prevented from adhering to the surface of the disk 101 when the disk 101 is not in use. Further, the jacket 103 is provided with a frame counter dial 109. This frame counter dial 109 is for displaying the number of recorded tracks, and is used when recording images.

Next, the configuration of the recording/reproducing apparatus main body 200 will be explained. A disk drive motor 202 is fixed to the central portion of the chassis 201. A chuck magnet 204 is coaxially attached to the spindle 203 of the disk drive motor 202. The spindle 203 and the chuck magnet 204 are designed to rotate around a fixed shaft 205. Further, a regulation plate 206 is fixed to the chassis 201, and this regulation plate 206 is fixed to the chassis 201.
06 is provided with regulating pins 207 and 208. In the hole 209 provided in the regulation plate 206,
The magnetic head 210 is housed with its tip slightly protruding from the regulating plate 206. The magnetic head 210 is moved in the radial direction of the disk drive motor 202 by a head feeding mechanism (not shown).

First holder 211 for chassis 201
A second holder 212 is rotatably attached via a shaft 213. A holding plate 215 including a stabilizing plate 214 is attached to the inner surface of the first holder 211 . The above retaining plate 21
A pulse generator coil (hereinafter abbreviated as PG coil) 216 for detecting the rotational position of the magnetic disk 101 is fixed to 5 . In addition,
The retaining plate 215 has three adjustment screws 217, 21.
8 and 219, the regulation pins 207 and 208 provided on the chassis 201 side and the fixed shaft 20
5, the position is adjustable. Note that the retaining plate 215 is attached to the first holder 211,
It is supported via a position-adjustable elastic member (not shown).

On the other hand, the second holder 212 has bent portions 220 and 221 on both sides thereof, and is designed to guide the magnetic disk pack 100. A pin 222 is provided inside the bent portion 220. This pin 222 is connected to the shutter 1.
It is planted at a position corresponding to 08. A large notch 2 is provided on the wall surface of the second holder 212.
23 are provided.

Note that as shown in the figure, the first holder 211 is
The structure is such that it surrounds the holder 212.

Next, the operation of the conventional example configured as described above will be briefly explained. In the state shown in FIG. 3, when the magnetic disk 101 is inserted into the second holder 212 from one end as shown by the dashed-dotted arrow, the shutter 108 is opened by the pin 222 in the process. Note that the shutter lock device (not shown) is also released at the same time. Next, with the first holder 211 and the chassis 201 in a substantially parallel state, they are locked by a locking mechanism (not shown). In this state, the magnetic disk pack 100
is positioned and supported with respect to the chassis 201 by a reference pin (not shown) or the like. A center core 102 located at the center of the magnetic disk 101 is fixed to a spindle 203 of a disk drive motor 202 by a chuck magnet 204. The magnetic disk 101 is located within the gap created by the regulating plate 206 and the stabilizing plate 214. When the disk drive motor 202 is rotated at a high speed (usually 3600 RPM) in this state, the disk 101 is stably guided by the regulating plate 206 and the stabilizing plate 214 and comes into stable contact with the magnetic head 210. This is mainly because an air layer is formed between the stabilizer plate 214, the regulating plate 206, and the disk 101 as the disk 101 rotates at high speed. Thus the magnetic head 21
0 enables information to be recorded and reproduced on the disk 101.

The reason why the holders 211 and 212 have a double structure is that the stabilizing plate 214 is attached to the jacket 1.
03 and close to the disk 101, for example, when the jacket 103 is fixed to the second holder 212, the stabilizing plate 214 prevents the jacket 103 from being inserted into or removed from the second holder 212. This is to put it away. In other words, the first
The holder 211 is configured to rotate more widely with respect to the chassis 201 than the second holder 212.

Further, the actual rotation angle of the holders 211 and 212 is smaller than the state shown in FIG. 3. In other words,
The above angle is such that the jacket 103 is attached to the spindle 203 and the regulating plate 206 with respect to the second holder 212.
It is sufficient that the jacket 103 does not come into contact with it when it is inserted or removed.

By the way, the PG coil 216 as a rotational position detector detects the magnetic flux from the tracking magnet 204 obtained through a magnetic piece (not shown) provided in the center core 102, and is used for recording and reproducing. This type of PG coil is also used in a magnetic sheet device as shown in, for example, Japanese Utility Model Application Publication No. 58-69372.

FIG. 2 is a diagram showing a typical example of a conventional PG coil. In FIG. 2, 301 is a ferrite rod with a sharply pointed conical tip, and this ferrite rod 301 is made of a plastic bobbin 3.
It is inserted into the hollow part of 02. Above bobbin 30
A coil 303 is wound around the outer periphery of 2. The above ferrite rod 301, bobbin 302, coil 30
3 is integrated with an adhesive or the like.

[Problem that the invention attempts to solve]

The conventional PG coil with the above configuration had the following problems. That is, it is necessary to align the tip of the ferrite rod 301 accurately with the rotation locus of the magnetic piece called the PG yoke, but since the magnetic flux is concentrated at the sharp tip, this magnetic flux concentration It was extremely difficult to match the points accurately, and it was necessary to make fine adjustments after installation.

The present invention was developed taking these circumstances into consideration, and its purpose is to provide a rotational position detection device for a rotationally driven body that is easy to adjust and capable of highly accurate rotational position detection. do.

[Means for solving problems]

In order to solve the above problems and achieve the purpose, the present invention takes the following measures. That is, when the rotationally driven body is at a certain rotational position with respect to the magnetic piece disposed at a predetermined part of the attached rotationally driven body, the tip end of the body is positioned close to and opposite to the magnetic piece. a detector comprising a core formed such that at least the tip portion forms a linear edge of a predetermined size, and a winding wound around the core; It was configured to detect the rotational position of the rotary drive body.

[Effect]

By taking such measures, the following effects are achieved. In other words, since the tip of the core is formed to form a linear edge of a predetermined size, positioning adjustment with respect to the magnetic piece placed at a predetermined portion of the rotationally driven body is easy and can be performed with high precision. becomes.

〔Example〕

Next, one embodiment of the present invention will be described. 3 and 4 are diagrams showing an embodiment in which the present invention is applied to a magnetic disk recording/reproducing apparatus, and FIG. 3 is a diagram showing the relationship between the magnetic disk pack 100 and the holder 400. Note that the same parts as in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted. The center core 102 is provided with a PG yoke 102A. on the other hand,
The holder 400 is made of aluminum, plastic,
It is formed of a steel plate or the like, and mounting holes 401 and 402 are provided at one end on both sides for rotatably mounting it to the chassis. Holder 4
A bent portion 403 bent downward in the figure is provided at a position facing the PG yoke 102A on the wall surface of 00. A PG coil 404 as a detector is attached to this bent portion 403 as shown by a broken line.

Two square holes 405, 4 are provided around the bent portion 403.
06 and two slits 407 and 408 are provided so as to face each other. These square holes 405,
406 and slits 407 and 408 are the bent portion 4
This is to adjust the position of 03 in the direction of arrow A-B. For example, if you insert a flathead screwdriver into the slit 407 and widen the slit width,
The bent portion 403 is displaced in the entrance direction of the holder 400.

FIG. 4 is a diagram showing the PG coil 404 taken out in a vertically inverted state. As shown in FIG. 4, the bending portion 403 includes a PG having a winding wire 410 wound around a core 409 whose tip is chamfered and formed to form a linear edge of predetermined dimensions.
A coil 404 is attached. Note that the circle indicated by the broken line indicates the rotation locus of the PG yoke 102A.

In this embodiment configured in this way,
The tip of the core 409 of the PG coil 404 is formed to form a linear edge with a predetermined dimension W, and is arranged along the radial direction of the disk so that the edge is perpendicular to the magnetic flux generated by the PG yoke 102A.
Moreover, since the width W of the edge is formed to be sufficiently larger than the width of the PG yoke 102A, even if the holder 400 is guided by the mounting holes 401, 402 and shifts in the directions of arrows C and D, the winding 4
The detection output obtained at 10 is stable, and the rotational position of magnetic disk 101 can be detected satisfactorily.

Furthermore, square holes 405, 406 and slits 40
7,408, and the position of the bending part 403 is indicated by arrow A.
- Since it is adjustable in the B direction, the magnetic disk 1
The timing of the rotation position of 01 can be easily finely adjusted.

Note that the present invention is not limited to the above embodiments. For example, in the embodiment described above, an example was shown in which the edges of the core 409 were arranged along the radial direction of the disk, but the edges do not necessarily have to coincide with the radial direction of the disk. Further, although a magnetic disk is illustrated as an example of a rotationally driven body, the present invention is not limited to this. It goes without saying that various other modifications can be made without departing from the gist of the present invention.

[Effect of idea]

As described above, according to the present invention, the tip of the core of the detector is formed to form a linear edge having a predetermined dimension, and the winding wire is wound around this core.
It is possible to provide a rotational position detection device for a rotationally driven body that is easily adjustable and capable of highly accurate rotational position detection.

[Brief explanation of the drawing]

Figures 1 and 2 are diagrams showing conventional examples.
The figure is a perspective view showing the overall configuration of the device, and the second figure is
FIG. 3 is a perspective view showing a PG coil. Figures 3 and 4 are views showing one embodiment of the present invention, with Figure 3 being a perspective view showing the structure of the magnetic disk pack and holder, and Figure 4 being an enlarged perspective view of the PG coil portion. It is. 100...Magnetic disk pack, 102...Center core, 102A...PG yoke, 200...
Magnetic disk recording/playback device body, 216...PG
Coil, 400... Holder, 403... Bent part (core), 404... PG coil, 405, 406
...Square hole, 407,408...Slit, 409
... Core, 410 ... Winding wire.

Claims (1)

[Scope of utility model registration request] When the rotationally driven body is at a certain rotational position with respect to the magnetic piece disposed at a predetermined part of the mounted rotationally driven body, the tip of the magnetic body is provided so as to be close to and opposite to the magnetic piece. and a core formed such that at least the tip portion thereof forms a linear edge of a predetermined size, and a winding wound around the core, A rotational position detection device configured to detect a rotational position of a body.