JPH0442726B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a special structure of a vibration absorbing wheel suitable for use in a magnetic recording/reproducing device (VTR).

In VTRs, especially small portable ones, the resonance frequencies of the drum shaft that forms the rotating magnetic head device and its motor are close to each other, so resonance (torsional vibration) is likely to occur, and based on this, the reproduced image There was a tendency for so-called image shaking to occur.

In order to avoid this, a vibration absorbing wheel has conventionally been mounted on the rotating shaft as shown in FIG. This will be briefly explained above. 1 is a rotating shaft, 2 and 3 are bearings, and 4 is a lower drum (fixed), the inside of which forms a so-called bearing housing. 5 and 6 are bearing holders, 7 is a preload spring, and 8 is an injection hole through which adhesive is injected to fix the bearing 3 to the fixed drum 4. Reference numeral 9 denotes a rotating flange, which is press-fitted and fixed to the rotating shaft 1. 10 is a rotor of a rotating transformer, 11 is a rotating disk fixed to the side of the rotating flange 9, 12 is a head base, 1
3 is a rotating magnetic head (video head). 1
Reference numeral 4 indicates a stator of a rotating transformer which is provided to correspond to and be magnetically connected to the rotor 10 of the rotating transformer, 15 is a drum support member attached to the side of the stationary drum 4, 16 is a drum mounting bracket, and 17 is a drum support member. The upper drum (fixed), this fixed drum 17
is attached to the drum support member 1 via the drum mounting bracket 16.
5.

18 is a motor rotor boss attached to the lower end of the rotating shaft 1, 19 is a motor magnet case fixed to the boss 18, and 20 is a motor magnet placed in the case 19. This constitutes a rotor 21 of a flat type motor. 22
23 is a motor stator base plate attached to the bottom of the fixed drum 4; 23 is a flexible printed circuit board 26 attached to a metal plate 25 provided below the base plate 22 with a shield case 24 interposed therebetween; is a motor coil electrically connected to the circuit pattern of the printed circuit board 23, 27 is a motor printed circuit board mounted on the base board 22, and the circuit patterns of the printed circuit boards 23 and 27 are electrically connected, A power supply lead wire for the motor is taken out from the printed circuit board 27 even though it is not shown. And these 22
Stator 2 of flat motor with ~27 parts
8.

In the head drum constructed as described above, a vibration absorbing wheel 30 is attached to the rotating shaft 1 in order to avoid the torsional vibration mentioned at the beginning.

This vibration absorbing wheel 30 has conventionally been configured as shown in an enlarged cross-section in FIG. 2. That is, it has an outer wheel 31 and an inner wheel 32 formed into an annular shape and a disk shape, and these are made of metal so as to be relatively heavy. Reference numeral 33 denotes a center hole formed at the center of the inner wheel 32, through which the rotating shaft 1 is attached. 34 are these two wheels 31,
This is a molded member made of an elastic material that connects the wheels 32 to each other, thereby connecting both wheels 31 and 32 concentrically. This mold member 34 is made of, for example, rubber. In this case, the mold member 34 is formed from two upper and lower parts 35a and 35b, as is clear from FIG. When manufacturing the inner wheel 32, the upper mold member 35a is molded in advance, the lower mold member 35b is formed separately, and the outer wheel 31 is fitted and bonded to the lower mold member 35b. , and is bonded to the upper mold member 35a with an adhesive. Therefore, the adhesive is used between the upper surface of the lower mold member 35b and the lower surface of the outer wheel 31, between the lower surface of the upper mold member 35a and the upper surface of the outer wheel 31, and between the upper surface of the lower mold member 35b and the lower surface of the outer wheel 31. This is between the inner wheel 32 and the lower surface of the inner wheel 32.

As is clear from the above description, the wheel 30 uses adhesive at multiple locations, which not only complicates the entire manufacturing process, but also makes the wheel 30 difficult to use.
Two manufacturing molds are required for a and 35b, resulting in a relatively high cost.

The present invention avoids such drawbacks, and in explaining an example of the wheel 30 according to the present invention with reference to FIG. 3, parts corresponding to those in FIG. . That is, in the present invention, a plurality (about 10) of through holes 31a and 32a are provided on the inside of the outer wheel 31 and the outside of the inner wheel 32, for example, on the same circumference, and
Both wheels 31 and 32 including these through holes 31a and 32a are integrally molded using a molding member 34.

In this case, the numbers of through holes 31a and 32a of both wheels 31 and 32 are not necessarily the same (similar).
There is no need to do this, and when you twist and mold the third
As shown in the figure, there is no need for the upper and lower through holes 31a and 32a to correspond to each other. In this example, the outer diameter φ ₂ of the inner wheel 32 is larger than the inner diameter φ ₁ of the outer wheel 31 (φ ₁ <φ ₂ ).

Moreover, the inner wheel 32 in the present invention is
A peripheral surface portion 32b of the center hole 33 is horizontally bent to have a cap-like cross section.
A through hole 38 is provided near the center hole 33 at b.

The inner wheel 32 thus formed and the outer wheel 31 described above are used to form the wheel 30 shown in FIG. 3 using a mold as shown in FIG. 4, for example. That is, the center hole surrounding surface portion 32b of the inner wheel 32 is positioned at the inner diameter portion of the outer wheel 31 between the upper and lower molds 36 and 37 at a required interval, and the through hole 32
By injecting the mold member 34 into the mold space 40 and solidifying the mold member 34 with the outer peripheral surface portion provided with a corresponding to the inner peripheral surface portion of the outer wheel 31 at a required interval within the mold space 40. A wheel 30 shown in FIG. 3 is formed. Incidentally, this mold member 34 can be made of rubber, that is, SBR.

The wheel 30 formed in this way is attached to the rotating shaft 1
To install it, as shown in phantom lines in Figure 3,
The inner wheel 31 is inserted into the rotating shaft 1 at the center hole 33, and the peripheral surface 3 of the center hole 33 is inserted.
2b is brought into contact with the flange portion 1a fixed to the rotating shaft 1, that is, the cap-shaped bulge portion of the inner wheel 31 is fitted into the flange portion 1a, and the screw 39 is inserted into the through hole 38 provided in the peripheral surface portion 32b. By inserting the wheel 3 and tightening it to the flange 1a, the wheel 3
0 is integrally attached to the rotating shaft 1. Therefore, by making the cross-sectional shape of the inner wheel 32 into a cap shape in this way, it is possible to eliminate the dead space on the inner diameter side of the wheel 30, and moreover, it is possible to eliminate the dead space on the inner diameter side of the wheel 30. By molding the outer circumferential surface part with the mold member 34, the inner wheel 3 is moved from the rotating shaft 1.
The torsional vibration transmitted to the wheel 2 can be effectively transmitted to the molded member 34, thereby increasing the damping effect of the wheel. Further, the flange portion 1a protruding from the rotary shaft 1 in a flange-like manner is fitted into the cap-shaped bulge portion of the inner wheel 32, and the inner wheel 32 is
Since the wheel 30 can be fixed to the flange portion 1a protruding like a brim from the rotating shaft 1 with screws 39 in the through hole 38 provided near the center hole 33 of The wheel 30 does not shift or the entire wheel 30 tilts, and since the wheel 30 is screwed near the rotating shaft 1, the wheel 30 has good balance and can be stably supported without causing unnecessary vibration. The wheel 30 can be easily attached to and detached from the rotating shaft 1.

According to the present invention described above, the wheel 30 according to the present invention can be formed using one type of mold compared to the case shown in FIG. It has the feature that manufacturing costs can be lowered compared to conventional methods. In addition, in the wheel shown in FIG. 2, since the outer wheel 31 and the inner wheel 32 are each adhered (fixed) to the mold member 34 with an adhesive, the mold that is interposed only between the two wheels 31 and 32 is Only the member 34 contributed to the wheel effect as an elastic part, and since the distance between these wheels was short, the effect was low. On the other hand, according to the present invention, the mold member 34 is not bonded to both the wheels 31 and 32 in any way, but simply passes through the through holes 31a and 32a of both wheels. 31
Elasticity also occurs between a and 32a and the mold member 34, and in addition to this, the mold member 34 between both wheels 31 and 32 also becomes an elastic part, so the path of the elastic part is smaller than that in FIG. becomes longer (assuming the distance between wheels 31 and 32 is the same),
Therefore, it has the feature that the wheel effect can be improved accordingly.

In addition to the above-mentioned effects, by making the cross-sectional shape of the inner wheel into a cap shape, it is possible to eliminate dead space on the inner diameter side of the wheel, and as a result, torsional vibration transmitted from the rotating shaft to the inner wheel can be effectively transmitted to the wheel. It is possible to obtain an excellent damper effect by conveying the desired effect. Furthermore, since the inner wheel can be screwed onto the rotating shaft through a through hole near its center hole, the wheel will not shift in the radial direction with respect to the rotating shaft, and the entire wheel will not tilt. It also has the effect of supporting the wheels with good balance.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a head drum of a magnetic recording/reproducing device using a vibration absorbing wheel.
Figure 2 is a sectional view of the vibration absorbing wheel, Figure 3 is a sectional view of the vibration absorbing wheel.
The figure is a sectional view showing an example of a vibration absorbing wheel according to the present invention, and FIG. 4 is a sectional view showing a mold for forming this wheel. 30 is a vibration absorbing wheel, 31 is an outer wheel, 32 is an inner wheel, and 34 is a molded member.

Claims (1)

[Claims] 1 A rotating shaft rotated by a motor, a rotating drum having a magnetic head attached to this rotating shaft, and an inner wheel and an outer wheel each having a through hole formed therein are integrally formed using an elastic material in a concentric arrangement relationship. a vibration-absorbing wheel molded into a vibration-absorbing wheel, the vibration-absorbing wheel being disposed above the rotating drum on the rotating shaft;
The motor is disposed below the rotating drum, and the inner wheel is formed to have a cap-like cross section, and the inner wheel is fitted into a flange fixed to the rotating shaft and is disposed near the center hole. A rotary head drum device characterized in that it is attached with screws in a through hole.