JPH02199656A - Tape guide device - Google Patents

Abstract

PURPOSE:To reduce friction between a tape guide and a tape by adopting the hollow tape guide, mounting a vibrator made of a piezoelectric substance to the hollow inner surface and using the vibrator so as to exert vibration to the tape guide. CONSTITUTION:A hollow tape guide 28 is employed and a vibrator 40 made of a piezoelectric substrate is fitted to the hollow inner surface and the vibrator 40 exerts vibration to the tape guide 28. For example, a square chamfered throughhole is provided in the inside of the tape guide 28 and 4 piezoelectric substances 40a - 40d are adhered in a way of the polarization direction opposite alternately to each other to each side respectively. When a voltage is applied to the piezoelectric substances 40a - 40d for exciting them, the resonance mode appears and four nodes and four loops are formed on the surface of the tape guide 28, a secondary standing wave is caused, and a magnetic tape 14 wound on the tape guide 28 is energized by the standing wave and then floated. Thus, the contact area of the tape is reduced in comparison with the case of no standing wave and then friction is reduced.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape guide device, and more particularly to a tape guide device suitable for use in guiding tape-shaped recording media such as tape recorders and VTRs.

[Summary of the invention]

The guide body is made hollow, a piezoelectric material is pasted on the inner surface of the hollow part, and this piezoelectric material is excited by resonance or non-component, and the friction between the tape guide and the tape is reduced by the vibration generated on the surface of the tape guide. It was designed to reduce the

[Conventional technology]

In a VTR that uses magnetic tape as a recording medium, a fixed tape guide such as an inclined guide is used. Such friction between the tape guide and the tape cannot be ignored, and for example, the friction has a large effect on the rise time when switching from a stop state to a steady running state. Air guides are used to reduce this friction. In the air guide, the guide body is hollow, and microscopic holes are formed on the outer surface between the guide surface and the internal through-holes, so that compressed air is sent from inside and ejected through the microscopic holes. ing. The pressurized air comes out to the surface of the guide body, enters between the tape guide and the tape, lifts the magnetic tape from the guide, and thereby increases the radius of the magnetic tape.
I am trying to lower the tia. Also, Japanese Patent Publication No. 43-1427, Japanese Patent Publication No. 54-187
No. 10 or Japanese Utility Model Application No. 182983/1983 proposes a tape guide device that uses a piezoelectric material and uses microscopic imaging of the piezoelectric material to reduce friction. [Problems to be Solved by the Invention] Air guides that interpose compressed air between the tape guide and the magnetic tape not only require a pump to send the compressed air, but also require a filter to purify the air. In addition, there are drawbacks such as the tape guide hole being easily clogged and requiring constant maintenance. Furthermore, conventional tape guide devices that utilize minute vibrations caused by a piezoelectric body have a structure in which the image of an externally provided piezoelectric body is transmitted to the tape guide, and the tape guide is thereby moved. It has a disadvantage that it has a large structure and requires a large space when incorporated into a VTR. The present invention has been made in view of these problems, and it is an object of the present invention to provide a tape guide device that does not have a large structure, does not require constant maintenance, and is highly effective in reducing frictional force. The purpose is to Means for Solving Problem K] The present invention provides a device for guiding a tape by contacting the outer surface of the tape guide, in which the tape guide is made hollow and the inner surface of the hollow is made of a piezoelectric material. A vibrator is attached to the tape guide, and the vibrator is used to apply vibration to the tape guide. K effect] Therefore, when the piezoelectric body attached to the inner surface of the hollow part of the tape guide is excited, vibration will be generated on the surface of the tape guide, and this vibration will cause friction between the tape guide and the tape. It will be reduced. K Embodiment FIG. 5 shows an overall outline of a VTR equipped with a tape guide device according to an embodiment of the present invention.
R uses a tape cassette 10. The tape cassette 10 includes a cassette casing 11, and a pair of left and right reel hubs 12 inside the casing 11.
．． I am trying to arrange 13. The magnetic tape 14 is wound around a pair of glue hubs 12.13 and guided by tape guides 15.16 through the bottom opening 17.1.
It is designed to be hung inside the front lid 19 so as to cross the front cover 8. A head drum 22 is disposed on the front side of the mechanical deck of the VTR at the position where the tape cassette 10 is mounted. Guide rails 23 and 24 are arranged on both sides of the head drum 22, and sliders 25 and 26 move while being guided by guide grooves 31 and 32 of these rails 23 and 24, respectively. It looks like this. The slider 25 has a tape drawer bin 2.
7 and an inclined guide 28 are provided. Further, the other slider 26 is provided with a tape drawer bin 29 and an inclined guide 30. In the above configuration, the tape cassette 10 is
As shown in the figure, VTRG: When installed, the slider 25
．． Tape drawer bins 27 each provided in 26
, the inclined guide 28 , the tape drawer bin 29 , and the inclined guide 30 are located inside the magnetic tape 14 that is hung inside the front lid 19 of the tape cassette 10 . Therefore, when the sliders 25, 26 are moved along the respective guides fi 31, 32 of the guide rails 23, 24 by driving means (not shown) provided under the guide rails 23, 24 on both sides, the tape drawer bin 27, 29 and inclined guides 28, 30, the magnetic tape 14 is mounted so as to be wound around the outer periphery of the head drum 22, as shown in FIG. Then, the pinch roller 36 presses the magnetic tape 14 onto the cab stan 35. Therefore, the magnetic tape 14
is fed out from one reel hub 12, travels in sliding contact with the outer periphery of the head drum 22, passes between the capstan 35 and the pinch roller 36, and is wound up by the other reel hub 13. At this time, it is brought into contact with a rotary head provided on the head drum 22, thereby performing recording and/or reproduction using the helical scan method. Next, the inclined guide 2 pulls out the magnetic tape 14 from the cassette casing 11 and wraps it around the head drum 22.
The structure of 8.30 will be explained with reference to FIGS. 1 to 3. These tape guides 28 are characterized in that the friction between the magnetic tape 14 and the tape guide 28 is reduced by exciting a piezoelectric body 40 installed inside the tape guide 28, and the movement generated on the surface of the guide 28. It is. As shown in FIGS. 2 and 3, the tape guide 28 itself is composed of a cylinder having a diameter of, for example, 6n and a length of about 24un, and a square through hole 40 with rounded corners is provided inside the cylinder. It is being The tape guide 28 has a maximum wall thickness of 111 at the middle part of each side of the square through hole 39, and a minimum wall thickness of 0.5+n at each corner of the through hole 39. This dimension determines the resonant frequency and guide 2
The magnitude of the vibration amplitude generated on the surface of 8 is to be determined. The size of the piezoelectric body 40 is, for example, 2.7X24X0.
．． 2 mm, and the through hole 3 inside the tape guide 28
A total of four sheets, one on each side of 9, are attached using epoxy adhesive. Moreover, the piezoelectric body 40 is polarized in advance, and the polarization direction when pasting is as shown in FIG. 1A.
40a and 40G are polarized outward, and 40b and 40d are polarized inward. That is, four piezoelectric bodies 40a to 40d
are attached so that the polarization directions are alternately opposite. The four electrodes are short-circuited on the inside of the piezoelectric body to form one electrode, and the other electrode is taken from the tape guide 28. When a voltage is applied to the piezoelectric bodies 40a to 40d to excite them, 8
A resonance mode as shown in FIG. 1B appears around 6 kHz. At this time, when the piezoelectric bodies 40a and 40c contract and the piezoelectric bodies 401) and 40d extend, the tape guide 28 extends in the vertical direction and contracts in the horizontal direction, as shown in FIG. 1B. Piezoelectric body 408-4
When 0d expands and contracts in the opposite direction, the tape guide 28 extends in the left-right direction in FIG. As a result, four nodes and four antinodes are formed on the surface of the tape guide 28, and a second-order standing wave is generated. The magnetic tape 14 wound around the tape guide 28 is struck by this standing wave and becomes floating, reducing the contact area and friction compared to the case without standing waves. Factors that affect friction reduction include voltage, tape tension, and how the guide is supported. These all affect the magnitude of the standing waves. The higher the voltage, the better; however, if it is too high, the guide 28 itself may heat up and damage the magnetic tape 14. Therefore, in the case of this embodiment, the peak-to-peak ratio is 10
It is taken as the value of V. Furthermore, although the tape tension of the magnetic tape 14 is small, the throat friction is reduced, but the degree of dependence thereof becomes greater as the standing wave becomes larger. As for the method of supporting the guide 28, it is preferable to support both ends of the guide 28 with a minimum contact area so as not to suppress vibration as much as possible, or to support the guide 28 by sandwiching a soft material that does not suppress vibration. When we actually measured the friction coefficient using a friction measuring machine, we found that
When a peak-to-peak voltage of 10V is applied to the piezoelectric ceramic 40 and the tension is set to 70 (J), the I when no voltage is compared to the piezoelectric ceramic 40 is
The value was reduced to 4% compared to the 11 rub. The magnetic tape 14 used here is a 1/2 inch metal video tape, and the tape running speed is 1 On/sec.
The winding of the magnetic tape 14 has a 90" corner and a guide 28.
was supported by fixing one side to an aluminum block using epoxy resin. The vibration of the tape guide 28 is transmitted to the magnetic tape 14,
This may cause the magnetic tape 14 to vibrate. Such a motion of the magnetic tape 14 increases when the magnetic tape 14 contacts the antinode portion of the tape guide 28, and decreases when the magnetic tape 14 contacts a node. In other words, when the magnetic tape is wound as shown by the solid line in FIG. 4, the magnetic tape 14 touches the tape guide 2 at the vibration nodes.
8, the magnetic tape 14 also separates from the tape guide 28 at the node, and vibrations against the magnetic tape 14 are suppressed. On the other hand, as shown by the chain line in FIG. 4, the tape guide 28 starts to come into contact with the tape guide 28 at the antinode part of the imaging, and the tape guide 28hl etc. When the magnetic tape 14 is separated from the magnetic tape 14, the vibration of the tape guide 28 is easily transmitted to the magnetic tape 14. Next, a modification of the above embodiment will be explained with reference to FIG. In the modification shown in FIG.
A square through hole 39 is formed, and this through hole 39
A piezoelectric ceramic 40 is pasted on each side of the piezoelectric ceramic 40, and six piezoelectric ceramics 40 are pasted with their polarization directions alternately opposite to each other. Therefore, according to such a modified example, vibrations that have six antinodes and six nodes are generated. FIG. 8 shows yet another modification, in which the through hole 39 is circular. That is, the tape guide 28 is composed of a pipe. Four piezoelectric films 41 are attached to the inner surface of the through hole 39 of the tape guide 28 made of this pipe at positions shifted by 90 degrees in the circumferential direction. Since the compression film 41 made of a polymer film has flexibility itself, it is pasted along the inner surface of the through hole 39 having a circular cross section. In such a modification, the tape guide 28 can be configured by a pipe having a circular through hole 39, and the cost thereof can be reduced. [Effects of the Invention] As described above, the present invention makes the tape guide hollow, and attaches a vibrator made of a piezoelectric material to the inner surface of the hollow.
The vibrator is used to give an image to the tape guide. This vibration therefore makes it possible to reduce the friction between the tape guide and the tape. Furthermore, since the piezoelectric body is attached to the hollow inner surface of the tape guide, the external dimensions do not increase, and it can be assembled in the same space as conventional tape guides. Furthermore, since there are no parts that wear out and no dust is generated, it is possible to provide a tape guide device that does not require special maintenance.

[Brief explanation of the drawing]

Fig. 1 is an enlarged sectional view of a tape guide device according to an embodiment of the present invention, Fig. 2 is a perspective view of the same external appearance, Fig. 3 is a sectional view of a bored state, and Fig. 4 is a tape winding. Fig. 5 is a plan view of the main part of a VTR equipped with this tape guide, Fig. 6 is a plan view of the same magnetic tape mounted, and Fig. 7 is a modified example. FIG. 8 is an enlarged sectional view of another modification of the tape guide. The names of the main parts in the drawings are as follows. 14... Magnetic tape 28... Inclined guide 39... Through hole 40... Piezoelectric ceramic 41... Piezoelectric film

Claims (1)

[Claims] 1. In a device that guides the tape by contacting the outer surface of the tape guide, the tape guide is made hollow, and a vibrator made of a piezoelectric material is attached to the inner surface of the hollow, and the vibrator causes the tape to be guided by contacting the outer surface of the tape guide. A tape guide device characterized by applying vibration to the guide.