JPS62197949A - Rotary head assembly - Google Patents

Abstract

PURPOSE:To attach high fidelity and reliability on a device, by providing at least one recessed groove on the tape guide plane of a cylinder whose lower part is fixed. CONSTITUTION:The titled device is constituted of a cylinder 8, the tape guide plane 9 of the cylinder 8, and a recessed groove 10 provided on the tape guide plane 9. The tape guide plane 9 is a tape guide plane 5 having the same width remaining at both sides of the recessed groove 10, and the depth of the recessed groove 10 is set at a dimension within which no vibration of a magnetic tape 1 is generated, and the width of the recessed groove 10 is set at the dimension by which the magnetic tape 1 is guided without a trouble on the tape guide plane 9. Thus, frictional resistance between both particles generated in the traveling time of the magnetic tape 1, can be reduced, and squeaking between the magnetic tape 1 and the cylinder 8 whose lower part is fixed, can be prevented from generating, and the magnetic tape 1 is prevented from attaching on the cylinder 8 whose lower part is fixed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to a rotary head assembly for a VTR or the like.

(Prior Art) A conventional rotary head assembly of this type has an upper rotary cylinder 2 and a lower fixed cylinder 3, as shown in Figure 6, and the magnetic tape 1 is helically arranged so as to span both cylinders 2.3. It is wrapped around the vehicle and runs at a constant speed. magnetic head 4
is mounted on the upper rotating cylinder 2 and rotates under restraint, recording/producing signals on the magnetic tape l.

In addition, 5 is a tape guide surface, 6 is the rotating shaft of the upper rotating cylinder 2, and 7 is a bearing of the rotating shaft 6 provided in the lower fixed cylinder 3.

The tape running state of the rotary head assembly having such a configuration is very complicated.

FIG. 7 shows a cross section of a conventional rotary head assembly and the running state of the magnetic tape 1. Since the upper rotating cylinder 2 rotates at high speed, air is caught between the upper rotating cylinder 2 and the magnetic tape 1, creating a minute air layer.
That is, an air film is formed, and the magnetic tape 1 travels from the rotating cylinder 2 while moving a distance. However, since the relative speed between the magnetic tape 1 and the tape guiding surface 5 of the lower fixed cylinder 3 is small, an air layer is not formed as in a direct arrangement, and the magnetic tape 1 is attached to the tape guiding surface 5 of the lower fixed cylinder 3. In this way, in the conventional rotating head assembly,
The magnetic desol l is i1F in the upper rotating cylinder 2 part.
Although it travels without receiving any force, the lower fixed cylinder 30 portion travels while experiencing frictional resistance due to sliding motion.

This resistance is already greatest at the exit side of the magnetic tape l, since the contact area between the magnetic tape 1 and the tape guide surface 5 increases from the population side a of the magnetic tape 1 to the exit side.

For this reason, the following problems occurred. (1)! ! Running load is applied to the magnetic tape. (2) Squeaks occur between the magnetic tape l and the lower fixed cylinder 3. (3) In a high humidity atmosphere, the magnetic tape 1 adheres to the lower fixed cylinder 3, making it impossible for the magnetic tape 1 to run. (4
) The tape 1 is scratched and the magnetic film separates. (5
) The lower fixed cylinder 3 wears out.

Due to these factors, conventional rotary head assemblies have been unable to record and reproduce signals with high reliability.

It is an object of the present invention to solve these conventional problems and provide a rotating fixed assembly having high quality and high reliability.

(Means for Solving the Problems) A rotary head assembly according to the present invention is provided with at least one groove on the tape guide surface of the lower fixed cylinder.

[Effect]

The grooves in this invention reduce the contact area between the magnetic tape and the tape guide surface of the F-portion fixed cylinder, thereby reducing the frictional resistance between them that occurs when the magnetic tape runs. This reduces the running load on the magnetic tape, prevents squeaking between the magnetic tape and the lower fixed cylinder, and prevents the magnetic tape from adhering to the lower fixed cylinder in times of high humidity. It also reduces damage to the magnetic tape and wear on the lower cylinder.

[Embodiments of the invention]

1 to 3 show a first embodiment of the present invention, FIG. 1 is a side view, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIG. 3 is a sectional view showing the state in which the magnetic tape is wound. be.

In FIG. 1, the same or equivalent parts as in FIG. 6.7 are given the same reference numerals. 8 is a lower fixed cylinder, 9 is a tape guide surface of the lower fixed cylinder 8, and IO is a groove provided in the tape guide surface 9. In comparison with the conventional example, this groove 10 is provided on the tape guide surface 5 shown in FIG. 6.7. This is the tape guide surface 5. The depth of the groove 10 is set to such an extent that the running magnetic tape 1 does not swing.
The width of the groove 10 is such that the magnetic tape 1 can be guided by the tape guides Wi9 on both sides without any trouble. FIG. 2 is an enlarged view of the cross-sectional shapes of the tape guide surface 9 and the groove 10.

Projections 9a are provided on the surface of the tape guide surface 9 at a constant pitch P, but the bottom surface of the groove 10 is provided with projections 10a having the same pitch as the projections 9a, as shown in FIG. There are cases where it is provided, and cases where it is not provided as shown in FIG. However, in either case, the width P2 of the groove 10 is larger than the pitch P1 of the protrusions 10a.

Next, the action will be explained.

Since the groove 10 reduces the contact area between the tape guide surface 9 and the magnetic tape 1, the frictional resistance between the two 1.9 that occurs when the magnetic tape 1 runs is reduced accordingly.

If the frictional resistance is reduced, the running load on the magnetic tape 1 will be reduced, and no squealing will occur between the magnetic tape 1 and the lower fixed cylinder 8. Furthermore, even in times of high humidity, the magnetic tape 1 will not stick to the lower fixed cylinder 8 and become unable to run, and the magnetic tape 1 will not peel off or the lower fixed cylinder 8 will wear out. The frequency of doing so will also decrease.

4 and 5 show a second embodiment of the invention. 7
1') The same or corresponding parts as in FIG. 1 and FIG. 3 are given the same reference numerals.

In comparison with the conventional example, this embodiment has a plurality of grooves 11 on the tape guide surface 5 shown in FIG.
This is an example of 7 rows in the running direction. 12 is a tape guide surface formed in this way. The effect is the first
There is nothing essentially similar to that of the embodiment.

(Effects of the Invention) As described above, according to the present invention, since the concave groove is provided in the tape guide surface of the lower fixed cylinder, it is possible to obtain a rotary head assembly having high quality and high reliability.

[Brief explanation of drawings]

FIG. 1 is a side view of a rotary head assembly according to a first embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of the main part of FIG. 1, and FIG. 3 is a cross-sectional view showing the running state of the magnetic tape in the first embodiment. 4 is a side view of the rotary head assembly of the second embodiment, FIG. 5 is a sectional view showing the running state of the magnetic tape in the second embodiment, and FIG. 6 is a perspective view of the conventional rotary head assembly. FIG. 7 is a sectional view showing the running state of the magnetic tape in the conventional example shown in FIG. 2−−−−−−−− Upper rotating cylinder 8−= −−−
---Lower fixed cylinder 9...Tape guide surface 10-----Concave groove 111' Example 4P1 side view Figure 7 (a) (b) Key points of $1 implementation Enlarged sectional view Fig. 2

Claims (1)

[Claims] A rotary head assembly characterized in that a tape guide surface of a lower fixed cylinder is provided with at least one groove.