JPS5841417A - Rotary head drum - Google Patents

Abstract

PURPOSE:To fix a rotary head drum to a rotary shaft only with tightening of fixing screws without shaft deflection, by giving deformation due to elastic strain to a center shaft hole of the rotary head drum. CONSTITUTION:A plurality of opening holes 7 are formed near the circumference of a center shaft hole 5a of a rotary head drum 5 prior to the processing of the hole 5a so that the opening holes 7 have equal intervals mutually. Then, the center shaft hole 5a is shaped and processed and the thickness of external circumference of the center shaft hole 5a where the opening holes 7 exist is formed thin in thickness. This thin part is deformed toward the opening holes 7 during the processing of the hole 5a and restores to the original shape after the processing is finished to deform the hole 5a. This thin part, i.e., a deformed part 5b abuts on an external circumference 4b of a cylinder 4a when the center shaft hole 5a is inserted to the cylinder 4a of a flange 4, a clearance provided between the hole 5a and the external circumference 4b is damped and the centering of the rotary head drum 5 can be done.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating head drum for a helical scan video tape recorder.

In recent years, helical scan type VTRs have been widely adopted as video tape recorders (VTRs) for business use in broadcasting stations and the like.

In such a so-called professional VTIFL, high image quality, high reliability, and good maintainability are required, and therefore, the rotating head driver generally has an axial deviation of 6 m. In addition, when the magnetic head or drum becomes worn or damaged, it must be able to be replaced quickly and easily, and the required accuracy can be easily maintained at that time.

In order to meet such demands, rotary head drums such as those shown in FIGS. 1 and 2 have conventionally been used.

1 and 2, 1 is a fixed guide drum, 2 is a rotating shaft, 8 is a bearing, 4 is a flange member, and 5 is a rotating shaft.
is a rotating head drum, and 6 is a mounting screw.

The rotating shaft 2 is supported by a guide dot IK by a bearing 8, and is rotationally driven at a predetermined rotational speed by a driving means (not shown).

A cylindrical portion 4m is formed on the flange member 1, and is fixed to the rotating shaft 8 by tight fit or the like.

The rotating head drum 5 has a cylindrical portion 4aK with a flange member number.
A center shaft hole 5m is formed to fit into the center shaft hole 5.
m is inserted into the cylindrical portion 4a and then attached to the flange member 4 with a plurality of screws 6.

Therefore, according to this conventional example, the rotating head drum 5 can be easily attached and removed by tightening and removing the mounting screws 6, and the magnetic head (not shown) and the rotating head drum b can be easily attached and removed. Easy to replace when worn or damaged.

However, in this conventional example, the rotary head drum 6 is attached to the flange member 4 with the center shaft hole 6m inserted into the cylindrical portion 4a of the cylindrical member 40. The clearance between the outer circumferential surface 4b of the blade and the central shaft hole 5a of the rotary head drum 5 cannot be made sufficiently small.

That is, if this clearance is made small, it becomes difficult to insert or extract the center shaft hole 5m of the rotary head drum 5 into the cylindrical portion 4a, and the rotary head drum 5 can be easily attached or removed. This is because you will not be able to do it.

On the other hand, if the above-mentioned clearance exists between the center shaft hole 5a and the outer station 1i1i 4b, shaft wobbling will remain when the rotating head drum 5 is fixed to the flange member 4 with the mounting screws 6. There is a risk of it being lost.

In other words, when the rotary head drum 5 is attached to the rotary shaft 8 via the flange member number, the rotation center of the rotary head drum 50 is maintained by the fit of the center shaft hole 5a with the cylinder s4m, and therefore, this part If a clearance is provided for this, the shaft runout will be at most eight times the clearance.

Therefore, in the conventional rotating rad drum mentioned above,
When assembling or replacing the rotary head drum, it is necessary to adjust the centering of the rotary head drum, and in this case, special measuring tools such as a lever-type indicator are required to keep the shaft runout within an allowable value of, for example, 5 μm or less. Moreover, because it requires a high level of skill, maintenance work such as replacing rotating head drums and magnetic heads cannot be performed by users, such as VTR operators at broadcasting stations, etc., which reduces the operating rate of VTRs and requires maintenance. However, the disadvantage was that a considerable amount of cost would have to be considered.

An object of the present invention is to provide a rotating head drum that eliminates the drawbacks of the prior art described above and allows the rotating head drum to be fixed to a rotating shaft by simply tightening screws, with almost no shaft wobbling. is to provide.

In order to achieve this object, the present invention is characterized in that the central shaft hole of the rotary head drum is deformed by elastic strain, thereby absorbing the clearance of the fitting portion.

Embodiments of the rotary head drum according to the present invention will be described below with reference to the drawings.

Figures 8 and 4 show an embodiment of the present invention, and parts that are equivalent or the same as those of the conventional example shown in Figures 1 and 2 are given the same reference numerals, and detailed explanations thereof are omitted. .

The embodiments shown in FIGS. 8 and 4 are similar to those shown in FIGS. 1 and 2.
The only difference from the conventional example shown in the figure is that a plurality of openings 7 are provided near the periphery of the central shaft hole 5a of the rotary head drum 5 so as to be spaced apart from each other. When processing the rotary rad drum 6, these plurality of openings 7 are prepared in advance prior to processing the center shaft hole 5m.

Then, when cutting the central shaft hole 5 of the rotary head drum b, the outer circumferential wall thickness of the central shaft hole 5a becomes thinner in the areas where these openings 7 exist, and these The part 7a in Fig. 5 cannot withstand the stress applied in the outer circumferential direction by the cutting tool.
The central shaft hole 5a is machined in a state where elastic deformation as shown in FIG.

As a result, when the machining of the center shaft hole 5a is completed and the stress in the outer circumferential direction applied by the cutting tool is removed, M
The part shown in Figure 5? The part that had been deformed as shown in Jl 5 returns to its original state due to elasticity, and the center shaft hole 5a is deformed as shown in part 5b in Fig. 6, and only the part where the hole 7 was present on its inner peripheral surface is Make it into an inflated shape.

Then, if the material of the rotating head drum 5, the diameter of the center shaft hole 5 and the hole 7, and the wall thickness of the portion 7m or 5b after finishing are appropriately selected, the portion 5b17 shown in FIG. ) The dimension t is approximately equal to or slightly larger than the clearance between the central shaft hole 5m and the outer peripheral surface 4b of the cylindrical part number.

Then, when the central shaft hole 5a of the rotary head drum 5 is inserted into the cylindrical portion 4m of the 7-rank member 4, the plurality of deformed portions 5b formed near these openings abut against the outer peripheral surface 4b. Since the centering of the rotary head drum 5 was performed by absorbing the clearance provided between the center shaft hole 5a and the outer peripheral surface 4b, the rotary head drum 5 was simply inserted into the cylindrical portion 4a of the seventh rank member 40. If you can immediately obtain the correct rotation center by just doing this, it becomes K.

Therefore, after that, the rotary head drum can be mounted without any axial wobbling by simply tightening the screws 6 without requiring any adjustment.

At this time, the fitted state between the rotary head drum 5 and the cylindrical portion 4a of the flange member 4 is such that a plurality of deformed portions 5b
Even if there is no clearance, the rotary head drum 5 can be inserted into and removed from the cylindrical portion 4m smoothly, making installation and replacement easier. can be done.

That is, when inserting and removing the rotating head drum 5,
Even if the clearance between the deformed portion 5b and the outer peripheral surface 4b of the cylindrical portion 4a is zero, the wall thickness of these deformed portions 5b is considerably thinner, so that the rotating head drum 5
These deformed portions 3b are easily elastically deformed by the stress applied by insertion and removal into the shape 5 shown in FIG. 5, and therefore can be easily inserted and removed.

In addition, in order for the present invention to exhibit sufficient effects and to achieve a state of installation without shaft wobbling, the plurality of deformed portions 5b must be symmetrical with respect to the center of the rotating shaft 3, and at least 8 Needless to say, it is necessary to provide more than one.

Further, in the above embodiment, the plurality of openings 7 are round holes, but these are not limited to round holes and may be of any shape.

Furthermore, the center shaft hole 5a of the rotary head drum 5 may be directly fitted into the rotary ring 2 without providing the flange member 4&C cylindrical portion 4m.

In addition, the size of the bulge in Fig. 7 is several μm! In reality, the deformed parts 5b and 7b are almost invisible to the naked eye, as it is common for the deformed portions to be deformed by the naked eye, but Figures 5 to 7 are exaggerated to make it easier to understand. This is what is shown.

As explained above, according to the present invention, a plurality of holes are provided in the vicinity of the periphery of the central shaft hole of the rotary head drum in a simple structure, and the holes are provided at the fitting portion of the rotary head drum with respect to the rotation shaft. Since shaft wobbling due to clearance can be eliminated, the drawbacks of the conventional technology can be eliminated, and the rotary head drum can be easily installed and removed while maintaining high precision, making it possible to create a low-cost rotary head drum for helical scan type VTRs that is easy to maintain. can be provided with.

[Brief explanation of the drawing]

Figure 1 is a front view showing a conventional example of a rotating head drum;
8 is a front view showing an embodiment of the rotary head drum according to the present invention, FIG. 4 is a sectional view taken along B-B@, 11G5, 6, and FIG. 7 is an explanatory diagram for showing the action and effect. 1...-Fixed guide drum, 2...
・Rotating shaft, 8...Bearing, 4...
...Flange member, 41...Cylindrical part,
4b・・・・・・・・・Outer peripheral surface, 5・・・・・・・・・
・Rotating head drum, 5a...- Center shaft hole,
5b--Deformed part, 6--Curved part is screw, 7--Open hole, 7a--Deformed part. Figure 1 Figure 2 Figure 3 Figure 4 Figure 2155 Figure 6 Figure 7

Claims (1)

[Claims] (1) In a rotating rad drum that is attached to the rotating shaft via a flange member having a cylindrical portion that is fitted and fixed to the rotating shaft, a cylindrical portion formed on the rotating rad drum is fitted to the outer periphery of the cylindrical portion of the flange member. A plurality of holes are provided in the vicinity of the periphery of the center shaft hole to be processed, and the elasticity shape of the rad drum causes the rotation generated in the portion where the plurality of holes are provided during the processing of the center shaft hole to reduce the rotation of the seven-rank member. 4. A rotary head drum characterized in that the center shaft hole is fitted into the cylindrical portion in an elastic tight fit state. (section) In claim 1, the aperture is formed of at least eight round holes, and these round holes are provided at equal intervals along the vicinity of the periphery of the central shaft hole. The rotating head drum is characterized by