JPS5813982B2 - tape recorder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a tape speed variation phenomenon (generally called "wow and flak") caused by uneven rotation of a capstan shaft that occurs when a tape recorder runs the tape.

) This invention relates to a tape recorder designed to prevent such problems.

FIG. 1 shows the structure around the capstan shaft 1 in a conventional tape recorder, where 2 is a pulley that transmits the rotation of the drive belt 3 to the capstan shaft 1, and 4 is the structure between the capstan shaft 1 and the pinch roller 5. A pinch roller 5, which is a magnetic tape located between the capstan shaft 1 and the capstan shaft 1, moves toward and away from the capstan shaft 1 depending on how the tape recorder is used.

6 is an upper bearing that supports the radial load of the capstan shaft 1, and I is a lower bearing that supports the axial load.

In the conventional device with the above configuration, the drive belt 3 and the pulley 2
Even if the capstan shaft 1 is rotated through the capstan shaft 1, if the pinch roller 5 is kept separated from the capstan shaft 1,
The vinyl roller 5 does not rotate, and the magnetic tape 4 and capstan shaft 1 are in a sliding state.

When running the magnetic tape 4, when the pinch roller 5 is pressed against the rotating capstan shaft 1 with the magnetic tape 4 held between them, the axial length is longer than the width of the magnetic tape 4. A pinch roller 5, which is generally made of an elastic material such as rubber, rotates together with the capstan shaft 1, and the magnetic tape 4 between them runs at a speed equal to the outer peripheral speed of the capstan shaft 1.

By the way, in such a conventional tape recorder, eccentricity, backlash, friction, unbalance, slip, etc. of each rotating part appear as rotational unevenness of the capstan shaft 1, and this rotational unevenness of the capstan shaft 1 is caused by magnetic This not only causes uneven speed of the tape 1 (wow, flak), but also inevitably causes fluctuations in the frequency of the reproduced signal. Improvements such as increasing the speed have been made, but there are limits to this type of improvement, and there are certain limits to suppressing the speed unevenness phenomena (wow, flak) and fluctuations in the reproduction frequency.

The present invention is based on an idea different from the above-mentioned conventional improvements, and solves the problem of capstan shaft unevenness, that is, tape speed unevenness,
This is intended to reduce fluctuations in the reproduction frequency, and an auxiliary shaft having a flywheel is disposed near the capstan shaft, and the auxiliary shaft rotates via an elastic body that receives rotation of the capstan shaft. By constructing a torsional vibration system vibration absorber, the above-mentioned drawbacks are eliminated.

The invention will now be described with reference to illustrated embodiments.

FIG. 2 shows the basic configuration on which the present invention is based, and reference numerals 1 to 7 indicate the same components as in the conventional device shown in FIG.

Thus, 8 is an auxiliary shaft arranged parallel to the capstan shaft 1 at an appropriate distance, and 9 is stretched between a small pulley 10 of the auxiliary shaft 8 and an intermediate pulley 11 attached to the capstan shaft 1. , is an endless belt made of an elastic body, and the auxiliary shaft 8 is equipped with a flywheel 12.

13 and 14 indicate bearings of the auxiliary shaft 8.

In the tape recorder having the above configuration, when the capstan shaft 1 is rotated via the drive belt 3 and the pulley 2, the auxiliary shaft 8 having the flywheel 12 is also rotated via the intermediate pulley 11, the belt 9, and the small pulley 10. A torsional vibration system composed of a rotating and running belt 9 and an auxiliary shaft 8 having rotational inertia absorbs rotational irregularities of the capstan shaft 1.

That is, when the belt 9 made of an elastic material runs, since the belt 9 has spring characteristics in its running direction, a torsional vibration system is formed by the spring characteristics and the rotational inertia around the auxiliary shaft 8 having the flywheel 12. Therefore, when rotational unevenness occurs in the capstan shaft 1, by matching the natural frequency of the torsional vibration system to the frequency of the rotational unevenness, the rotational unevenness of the capstan shaft 1 is absorbed by the auxiliary shaft 8 having the flywheel 12. and decrease.

If the uneven rotation of the capstan shaft 1 contains various frequency components, a plurality of auxiliary shafts each having a flywheel may be provided and each of these shafts may be arranged to rotate via an elastic body using the rotational force of the capstan shaft. By configuring a plurality of torsional vibration systems, and by making the natural frequency of each of these torsional vibration systems match the individual frequency components of the rotational unevenness, all rotational unevenness of the capstan shaft 1 can be eliminated. is absorbed, and fluctuations in the reproduction frequency are prevented.

However, in the above configuration, the distance between the cab stan shaft and the auxiliary shaft with the flywheel is constant, so if the belt connecting both shafts is the same, the natural frequency of the torsional vibration system is limited to a constant value. It turns out.

Therefore, in addition to the above configuration, the present invention is characterized in that the position of the auxiliary shaft can be adjusted to adjust the distance between the auxiliary shaft and the capstan shaft,
This configuration makes it possible to change the natural frequency of the torsional vibration system by changing the transmission force of the rotation transmission mechanism between the auxiliary shaft with a flywheel and the capstan shaft, which rotates in response to the rotation of the capstan shaft. This makes it possible to easily match the vibration frequency that can be absorbed by the torsional vibration system to the frequency of rotational irregularities that should be absorbed by the capstan shaft.

To explain the embodiment shown in FIG. 3, bearings 13 and 14 of an auxiliary shaft 8 equipped with a flywheel 12 are supported by a bearing housing 15, and the bearing housing 15 is movable with respect to a fixed base 16 so that the auxiliary shaft 8 capstan shaft 1
It is now possible to change the distance between the two.

Reference numeral 17 denotes an adjustment bolt for adjusting the position of the bearing housing 15, and thus the auxiliary shaft 8. Its base is screwed into the threaded portion 16a of the fixing base 16, and its tip is inserted through the through hole 15a of the bearing housing 15. A retaining ring 18 that engages with the wall surface of the bearing housing 15 is attached to the tip thereof.

19 is a compression spring for pressing the bearing housing 15 toward the capstan shaft 1, and 20 is a clamp bolt for fixing the bearing housing 15 to the fixing base 16 via the spacer 21.

Note that the other configurations are the same as those of the apparatus shown in FIG. 2, so the same parts are given the same reference numerals and the explanation will be omitted.

According to the present device having the above configuration, the bearing housing 15 moves forward and backward by the rotating operation of the adjustment bolt 17, and the distance between the auxiliary shaft 8 and the capstan shaft 1 is adjusted.

Therefore, since the tension of the belt 9 stretched between the small pulley 10 and the medium pulley 11 of both shafts 8 and 1 is adjusted by the above operation, it can be absorbed by the natural frequency of the torsional vibration system, that is, by the main torsional vibration system. The vibration frequency can be changed, and in response to the uneven rotation of the capstan shaft 1 that causes fluctuations in the reproduction frequency, any frequency component of the frequency of the rotational irregularity can be reduced to effectively prevent fluctuations in the reproduction frequency. This makes it possible to reduce the

In addition, even in the above configuration, it is possible to provide a plurality of auxiliary shafts each having a flywheel whose position can be adjusted with respect to the capstan shaft, thereby absorbing various frequency components of rotational irregularities of the capstan shaft 1. Of course.

In the above description, as an embodiment of the present invention, the capstan shaft 1 and the auxiliary shaft 8 are connected by a belt 9 made of an elastic body. Even if an idle roller made of a body is arranged and the auxiliary shaft is rotated by the rotation of the capstan shaft via the idle roller, the same effect as the above embodiment can be obtained as a torsional vibration system.

As described above, the tape recorder of the present invention has a torsional vibration system by installing an auxiliary shaft equipped with a flywheel and configuring this auxiliary shaft to rotate in response to the rotation of the capstan shaft via an elastic body. In addition, the auxiliary shaft is provided so that its position can be adjusted to adjust the distance between the shafts and the capstan shaft, so that the natural frequency of this torsional vibration system can be adjusted to the frequency of rotational unevenness of the capstan shaft. This makes it easy to match, and this makes it possible to reduce the uneven rotation phenomenon (wow, flak) and rotate the capstan shaft at a nearly constant speed, which also contributes to reducing fluctuations in the reproduction frequency. effective.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing the configuration around the capstan shaft in a conventional tape recorder, FIG. 2 is a sectional view showing the basic configuration that is the premise of the present invention, and FIG. FIG. 2 is a front view showing an embodiment of the invention, with a part of the area around the capstan shaft in cross section. 1: Capstan shaft, 3: Auxiliary shaft, 9: Belt, 12:
Flywheel, 15: Bearing housing, 16: Fixed base.

Claims (1)

[Scope of Claims] 1. An auxiliary shaft having a flywheel is rotatably disposed near the capstan shaft, and the position of the auxiliary shaft is adjustable to adjust the distance between the shafts and the capstan shaft, A tape recorder further characterized in that the auxiliary shaft is configured to rotate via an elastic body that receives rotation of the capstan shaft. 2. The tape recorder according to claim 1, wherein the auxiliary shaft and the capstan shaft are connected by a belt made of an elastic body.