JPS6050737A - Rotary head assembly - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a rotary head assembly for a video tape recorder (hereinafter abbreviated as VTR).

Configuration of Conventional Example and Its Problems As a conventional example, a VH8 type VTR will be explained. The conventional rotary head assembly has a magnetic tape (hereinafter abbreviated as tape) 1 and 7, as shown in FIG.
1, rotation of the rotary tank ΦJ1 at 1000 to 200 Orpm) 11 A2 and a fixed member 3 that slides in a non-rotating manner support this fixed part It3-1
- is provided with a lead 4 for controlling the position of the tape 1 during running. Rotation) 91 (Mounted on material 2-1, 11) The magnetic head 5 helically scans the tape 1 from 4 to 1', thereby rotating the tape 1%.
fi video 1. -', ; , 1-j reliable input/output is realized. 4: :I'b.6 is a magnetic head mounting window. The magnetic head 6 protrudes outward from the outer peripheral surface of the L rotating member 2 by approximately several tens of microns [7] and is held therein.

Video credit? The magnetic head on the rotary member, which is used to generate the human output, is l! -: The I-unit rotates and comes into contact with the tape, and abrasion occurs between the magnetic head surface and the tape, producing abrasion particles.The tape also comes into contact with a part of the rotating member, and wear occurs here as well. Because of this, abrasion powder is generated, and this C abrasion powder moves while being attached to the rotating member-1-Fuji. Towara I (E) At the early stage of the development of powder (l-f
: Although it has a diameter of 4 several microns, it is the rotating member-1! It accumulates in a certain area and grows to a diameter of 1 to 10 microns or more. The abrasion powder on the rotating member formed through these steps moistens itself or the tape and moves at high speed (
The phase 71 slides on the outer periphery j'[) of the rotating member, forming a kind of built-up edge, which aligns with the tape and causes damage, including delamination of the magnetic layer. Actual time! 1℃
With the exception of the magnetic head that slides in direct contact with the magnetic orientation of the tape, on the rotating member, the vertical edge of the magnetic head mounting window downstream 1011 (i.e. on the lagging side) in the direction of rotation of the magnetic head contacts and slides on the tape. to move,
This has been revealed through optical measurements using a photonic sensor, and in reality, the accumulation of magnetic powder can be confirmed in the above locations.

Furthermore, during still picture playback (hereinafter referred to as still playback), which is a type of special playback, a magnetic head on a rotating member sweeps and plays back the same location on the tape while the tape is stopped running. In this case, due to local deformation of the region corresponding to the magnetic head sweeping section due to local deterioration of the tape, the tape may come into close contact with the gap between the rotating section 4g and the 1-. , (contact between the vertical edge of the downstream side of the magnetic head mounting window and the tape - the contact sliding becomes severe, and ! 11° is popular in high humidity (90%
In the case of 1471 (1-) below, the magnetic layer of the Ql tape is peeled off and the damage to the Q tape is significant.

- Due to the necessity of developing a small 1111 light + 11° type VTR, it is required to double the tape 11'tll (lζi+, magnetic recording density direction).That is, tape I-1: Juto's ferrite or 2 Coat magnetic powder of black oxide with a resin binder and apply nickel-cobalt alloy 4 vapor to the 4fl base plate or apply JJc to the coated metal tape. In this case, the human face hardness of the metal tape is -1-:Yl
do. (6) The sliding condition with the rotating head assembly on the other side becomes metal-to-metal, and the applicant has developed the present applicant as a method to improve the wear condition (C). As shown in Fig. 3, a spiral group 9 is formed between the rotating part '4'A7 and the fixed member 8, and the movement generated by utilizing the rotational force 4 of the rotation r'+++44-r. Under pressure (air 11): slight wrinkles/stiffness all around the rotating spatula door, (6 to 20 it nl)
) A rotating head assembly with a new configuration that holds the F7-J has already been proposed for 1JL [7]. However, a spiral group is not provided in the vicinity of the magnetic head mounting window 6 due to the structure, and a predetermined discharge air pressure is not generated. Therefore, the effect of the spiral group does not work only in the vicinity of the head mounting window, and the difference d from the conventional rotary head assembly is eliminated. When performing still playback under the above conditions, tape damage may occur under adverse environmental conditions such as high temperature atmosphere.Objective of the Invention In view of the above disadvantages, the present invention has been developed to remove magnetic head waste from the vertical direction on the downstream side of the window. Properly configure the shape of the directional edge to minimize tape damage and achieve high reliability! IIl'i'i provides a complete range of highly durable rotating head assemblies.

Structure of the Invention The present invention provides a fixing member having a fixed cylindrical portion, a magnetic head having approximately the same diameter as the fixing member, and a magnetic head provided on the same axis in close proximity to the fixing member. a rotating member that rotates; a magnetic head that is provided on the rotating portion and that is included in the magnetic head; a magnetic head mounting portion and the rotating portion;
An example of this is a magnetic head mounting window that shares a circumferential surface with the magnetic head mounting window on the rotating member. 1
5. At the lower part of the magnetic head mounting 1.1 window straight edge on the downstream side with respect to the rotational direction of the material, there is an outer circumferential surface of the rotating member and 1) 1f.
The magnetic head IIV (
・1 window bottom l#, 11:114 A groove including a straight edge is provided, and 4I Contact running state with the tape!:!Lj 4-Turn it completely (12, extend the tape life in a trace way and static Il to 11: 11bi
Even under severe usage conditions, such as when operating a VTR, it is possible to use magnetic tape as a VTR with good audio and video signal input/output characteristics for a stable period of time. It is said that it is possible to maintain 11!1)
It has the utility of 7.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.C)
FIG. 8 is a bottom view showing the position of the spiral group provided on the upper bottom surface of the rotation τH47 in the first embodiment of the present invention. A magnetic head mounting portion 6-a including a magnetic head mounting window 6 for mounting the magnetic head 6 is provided on the bottom surface of the rotating member 7, and the other approximately concentric area r[the spiral group 11 and the land 12 They are arranged alternately. A groove 10 having approximately the same depth as the spiral group 11 is particularly formed on the downstream vertical edge of the magnetic head mounting window. Note that the number in FIG. 4 indicates the direction of rotation of the rotating member. On the rotary head assembly having the magnetic head mounting window configured as described above, the deformation behavior of the tape especially in the vicinity of the magnetic head is shown in Figures 6 1 to 3 based on actual 4J11 data obtained by a photonic sensor. To explain, FIG. 6 shows the deformation of the tape 1 in the vicinity of the magnetic head in a current rotary head assembly that does not have a spiral group. A dent in the direction opposite to the direction in which the magnetic head protrudes can be seen. Fig. 6 2 shows the case where a spiral group is provided, and the tape 1 is in contact with the vertical edge 6-b on the downstream side of the magnetic head mounting window where there is no spiral group. do.

On the other hand, as shown in FIG. As a result, the local contact between the head mounting window downstream (1111-Illill'+ edge 6-b and tape 1 is
1. As a result, not only in the normal table row state but also during still playback, the tape does not come into contact with the rotating iτ1 axis 4'A7. The reason why the groove 10 is not effective in avoiding local contact with the tape 1 will be explained in detail. As mentioned above, there is no effect of the spiral group C1 in the vicinity of the window 6 for several magnetic heads. In this state, if we consider the tape as a thin elastic body and analyze the deformed shape at the magnetic head mounting window based on elasticity theory, as shown in Figure 6, the tape 1 is located at the magnetic head mounting window at the lower end of the rotating section 4. As a result, during still playback, the same location on the tape is repeatedly subjected to frictional action, causing the magnetic layer of the tape to peel off. However, groove 1
By providing 0, it is possible to avoid collisions due to the shape. On the other hand, as a completely different effect, when the rotating member 7 rotates in the direction A as shown in FIG.
The trapped air in region B is concentrated on the downstream side due to the inertial force that moves as the rotating member 7 moves in volume due to its own rotation, resulting in high pressure. Since the tape 1 is ejected from the groove 1o as shown by the arrow F, this effect locally deforms the tape 1 in the air ejection direction, thereby avoiding contact with the vertical edge 6-b on the downstream side of the magnetic head mounting window. In short, the groove 10 serves both as a gap to prevent contact due to its shape and as a discharge port for discharging high pressure generated by the natural compression of air as the rotating member rotates. According to this embodiment, the groove 10
By providing the tape at the lower end of the downstream vertical edge of the magnetic head mounting window, contact between the tape and the downstream vertical edge of the magnetic head mounting window can be completely avoided. Therefore,
It completely eliminates tape damage during still playback, which was a problem with conventional tape floating rotary head assembly equipped with a spiral group, and greatly improves tape life. 10 faces 1 etj)ru I! We can provide all 'I1 quality rotary head assemblies. The groove depth of the groove 10 is approximately 5001t.It is difficult to set it to 111 or less, but if it is deeper than this, it will not be possible to apply enough force to deform the tape. . When a configuration is adopted in which a spiral group is provided in the single-rotating portion 71-, the groove 10 may be considered to be shared with the spiral group 11. Therefore, in this case, it is necessary to configure the vertical edge portion of the downstream 1111 of the magnetic head take-up window 1111 to start the spiral group. We have described the case where a spiral group (A) is provided on the 7th soil, but even if there is a configuration in which a spiral group (A) is provided on the 1-1 constant part (A-1-), the shape of 1111"I'10 itself is The effect of the groove 1o is the same even when the spiral group is not provided. As described in Section 25jj, the magnetic head mounting window does not necessarily have to have a TTi straight edge, and even if it is inclined from the vertical or has an arc-shaped curve, the above contents will still be effective. There is no loss of generality regarding.

Effects of the Invention As described above, the present invention has a fixing member having a fixed conical portion, and a magnetic conductor which is provided on the same axis in proximity to the fixing member, and which is approximately the same as the fixing member. a rotating member that holds all of the heads and rotates; a magnetic head mounting portion that is provided on the rotating member and includes the magnetic head; the number of magnetic heads +1; 11
, and a magnetic head mounting window, which rotates as described above) 9
The outer peripheral surface of the rotating member and the magnetic head mounting portion are connected to the lower part of the vertical edge of the magnetic head mounting window 1 (at 411-) downstream (71) in the rotational direction of the rotating member. By providing a continuous groove that includes a vertical edge on the downstream side of the magnetic head mounting window, the life of the tape is dramatically extended, and reliability and durability are ensured to withstand even severe usage conditions such as during still playback. It is possible to construct an excellent rotary head assembly with high performance and has great practical effects.

[Brief explanation of the drawing]

13 l-1 Figure 1C1 is a perspective view of the conventional rotary head assembly, Figure 2C1 is a cross-sectional view of the newly configured rotary head assembly;
Fig. 3 is a bottom view of the rotating part 11 in the rotary head assembly, Fig. 4 &-1: A bottom view of the rotating member in an embodiment of the present invention, and Figs. 6 (1) to (3) are magnetic head mounting windows. 1
Tape deformation near the hill 11111ial, cross-sectional view for Ming, Figure 6 C1, analysis of vertical deformation of the tape near the magnetic head 1 window The figure is a cross-sectional view of a portion illustrating the effects of the embodiment of the present invention. 1...Tape, 6...Magnetic head, 6...
...Magnetic head jIV, window, 6-a...Magnetic head mounting part, 6-b...Magnetic head additional window downstream vertical edge, 7...Rotation iτIS Material, 8...
...Fixing member, 1o...Groove, 11...
...Spiral Group. Name of 1111 people ′:jr:F! l! Ten Nakao
Toshio and 1 other person Figure 1 Figure 2 @ Figure 3 Figure 6 Figure 5

Claims (1)

Scope of Claims: (1) A fixing member having a fixed cylindrical portion, having an entire diameter substantially the same as that of the fixing member, and having an identical cylindrical portion adjacent to the fixing portion.
a rotating member which is provided on 1qII and rotates while holding a magnetic head; a magnetic head mounting portion which is provided on the rotating portion 2 and which includes the magnetic head; a magnetic head mounting portion and the rotating member; a magnetic head mounting window shared with the outer circumferential surface, and in the magnetic head mounting window on the rotating member, the rotating part The outer circumferential surface of the magnetic head mounting portion is communicated with the magnetic head mounting portion to the rotating head assembly 1 provided with a groove including a vertical edge downstream of the magnetic head mounting window 1ti11.(2) Either of the facing surfaces of the rotating member and the fixed portion The rotary head assembly according to claim 1, further comprising a pump-out type spiral group on one side. (3) A patent claim in which a bonshear-shaped spiral group is provided on the rotating member side of the facing surfaces of the co-rotating member and the fixed member, and the spiral group shares a groove on the downstream vertical edge of the magnetic head mounting window. A rotary head assembly according to scope 2. (4) In the vertical edge soil groove on the downstream side of the magnetic head mounting window, the depth from the similar end surface of the fixed part of the rotating member is 500 points.
The rotary head assembly according to claim 1 or 2, wherein the rotational head assembly is set to be less than or equal to m.