JPH0410123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary magnetic head device for a magnetic recording/reproducing device for recording and reproducing data on and from a magnetic tape, and more particularly to a rotary magnetic head device for a rotary magnetic head device having a configuration that can improve the assembly of the rotary cylinder. This relates to a centering mechanism.

First, the conventional technology will be explained. FIG. 1 is a top view schematically showing a magnetic recording/reproducing apparatus using a rotating magnetic head device 1. As shown in FIG. In the figure, a tape 3 contained in a cassette 2 is wound around a rotating magnetic head device 1 via guide pins 4 and 5, and is driven by a capstan 6 and a pinch roller 7. FIGS. 2 and 3 show a conventional rotating magnetic head device 1.
Figure 2 is a top view and Figure 3 is a top view.
FIG. This rotating magnetic head device 1 includes two magnetic heads 10a and 10.
b and a fixed cylinder 12 that guides the tape 3 and supports the rotating cylinder 8.
It is made up of. Bases 16a and 16b to which two magnetic heads 10a and 10b are respectively fixed are fixed to the rotating cylinder 8 by screws 17a and 17b. Moreover, this rotating cylinder 8 is
Shaft 1 supported by fixed cylinder 12
A fixing screw 15 is attached to the disk 9 that is integrated with the disk 8.
It is screwed by a and 15b. The fixed cylinder 12 fixed to the chassis 11 has a guide stage 12a on its outer periphery for guiding the tape 3, and further includes ball bearings 19a for supporting the shaft 18.
19b are arranged in two places, upper and lower. In addition, a rotary transformer 20 (not shown in FIG. 3) for transmitting signals between a video signal processing circuit and the magnetic heads 10a, 10b is provided. The rotating cylinder 8 with the above configuration is normally rotated at 1800 rpm,
A video signal recording track C as shown in FIG. 4 is scanned by magnetic heads 10a and 10b. In this case, if the rotating cylinder 8 is eccentric with respect to the shaft 18, the tape 3 as shown in FIGS.
The relationship between the magnetic heads 10a and 10b occurs, and the magnetic head scanning line on the tape 3 changes to the sixth magnetic head every time the two magnetic heads 10a and 10b alternately scan
It is known that the scanning locus changes as shown in Figures D and D'. Therefore, normally the rotating cylinder 8
It has become necessary to control the eccentricity to a few μm or less when assembling. By the way, conventionally, as a means for controlling eccentricity, when fixing the rotary cylinder 8 placed on the disk 9 with the fixing screws 15a and 15b, the outer periphery of the rotary cylinder 8 is corrected while being monitored with an electric micrometer or a dial gauge. We are taking steps to do so. However, this method has the disadvantage that the outer circumference of the rotary cylinder 8 is damaged or deformed, as shown by E in FIG.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art as described above, and to provide a rotary cylinder of a rotary magnetic head device that allows the rotary cylinder to be assembled with high precision without damaging or deforming the outer circumference of the rotary cylinder. To provide a centering mechanism. In order to achieve the above object, the present invention disposes feeders having tapered surface portions at several locations near the outer periphery of the disk, for example, at angular intervals of 120°, and feeds the rotary cylinder in the direction of the rotation axis or approximately in the direction of the rotation axis. As the feeder moves, the tapered surface portion of the side surface presses against the inner peripheral portion of the rotary cylinder, thereby finely moving the rotary cylinder in the radial direction.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 8 is a top view of the rotating magnetic head device of this embodiment, and FIG. 9 is an expanded sectional view taken along A'-O-B' of FIG. The rotating magnetic head device of this embodiment has a ninth
As shown in the figure, the structure is almost the same as the conventional example shown in Figures 2 and 3, except for the provision of three adjustment screws that serve as adjustment mechanisms, and the same symbols as the conventional example refer to the same parts. show. In this way, the rotating magnetic head device of this embodiment has the following features as shown in FIGS. 8 and 9.
Three adjustment screws 13 each consisting of a flathead screw that tapers toward the head and neck of the tightening section.
a, 13b, 13c near the periphery of disk 9.
They are arranged at 120° angular intervals. Furthermore, the inner circumferential surface of the rotary cylinder 8 and the outer circumferential surface of the disk 9 opposing the same are in a relationship with a higher step on the rotary cylinder 8 side, unlike the conventional examples shown in FIGS. 2 and 3. It's summery. Adjustment screws 13a, 13b,
13c, each tapered portion presses against the corner of the inner peripheral portion of the rotary cylinder 8, so that the eccentricity of the rotary cylinder 8 can be adjusted. This adjustment mechanism, as mentioned earlier,
Since they are arranged at angular intervals of 120 degrees, by feeding the adjusting screw while monitoring the outer circumference of the rotary cylinder 8 with an electric micrometer or dial gauge, the outer circumference of the rotary cylinder 8 can be adjusted without hitting the outer circumference of the rotary cylinder 8. The eccentricity of 8 can be adjusted.

As explained above, according to the present invention, when adjusting the eccentricity of the rotating cylinder of a rotating magnetic head device, the adjustment can be made without hitting the rotating cylinder as in the conventional case, thereby avoiding scratches on the outer periphery of the rotating cylinder. Peripheral runout can be reduced to several μm or less without attaching or deforming the material.

[Brief explanation of drawings]

FIG. 1 is a top view schematically showing a magnetic recording/reproducing apparatus using a rotating magnetic head device, FIG. 2 is a top view of a conventional rotating magnetic head device, and FIG. 3 is a top view of a conventional rotating magnetic head device.
-O-B developed sectional view; Figure 4 is an explanatory diagram showing the video signal recording track drawn on the tape by the magnetic head; Figures 5a and b are explanatory diagrams showing the relationship between the outer circumferential runout of the rotating cylinder and the tape. , Fig. 6 is an explanatory diagram showing the video signal recording track due to the outer circumference runout of the rotary cylinder, Fig. 7 is an explanatory diagram showing scratches or deformation on the outer circumference of the rotary cylinder caused by the conventional adjustment method, and Fig. 8 is an explanatory diagram showing the recording track of the video signal due to the outer circumference vibration of the rotary cylinder. A top view of one embodiment of the rotating cylinder centering mechanism according to the invention, FIG. 9 is similar to that of FIG.
It is an A'-O-B' developed cross-sectional view. Explanation of symbols 1 ... Rotating magnetic head device, 3... Tape, 8... Rotating cylinder, 9... Disk, 10
a, 10b...Magnetic head, 12...Fixed cylinder,
13a, 13b...adjustment screw, 15a, 15b...fixing screw, 18...shaft.

Claims (1)

[Scope of Claims] 1. A fixed cylinder having a tape guide, a rotating cylinder to which a magnetic head is attached, a disk to which the rotating cylinder is fixed concentrically, and a disk to which the rotating cylinder is aligned and fixed to the disk after centering adjustment. A centering mechanism for a rotary cylinder comprising a fixing member for fixing, wherein the disk is fitted in a portion of the rotary cylinder with a gap in the inner circumferential portion of the rotary cylinder in the direction of the rotation axis or approximately in the direction of the rotation axis. three or more insertion recesses are individually provided with a circumferential spacing of 180 degrees or less, and each of the insertion recesses has a tapered part, and the tapered part is arranged in the inner part of the rotary cylinder. 1. A centering mechanism for a rotary cylinder, characterized in that a pressure contact member is inserted into the rotary cylinder, the pressure contact member being in contact with the circumference and applying a radial movement force to the rotary cylinder according to the amount of insertion.