JPH08129809A - Tape guide mechanism - Google Patents

Abstract

PURPOSE: To obtain a tape guide mechanism capable of aborbing the variance of a shaft and its rigidity or working error in a massive system and assembling accuracy. CONSTITUTION: The mechanism is provided with the shaft 13, one end 13a of which is fixed, and a tape splicing member 14 fixed onto a specified position of this shaft 13. The tape splicing member 14 is oscillated and displaced by an exciting means 16 for oscillating the shaft 13. Also, a means 13d capable of changing the rigidity of the shaft 13 is provided therein. The shaft 13 is formed so that the rigidity is increased at the side of this fixed part 13a, particularly the cross sectional shape of the side of fixed part 13a is set to be larger than that of the side of s free end 13b. The specific massive system 12 is provided at the side of free end 13b of the shaft 13, and the supporting position of the massive system is made adjustable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape guide for guiding a tape-shaped recording medium used in a recording or reproducing device (hereinafter, simply referred to as recording / reproducing device).

[0002]

2. Description of the Related Art Of these types of recording / reproducing apparatus, tape guides used in magnetic recording / reproducing apparatuses such as VTRs that use magnetic tapes are roughly classified into two types, so-called fixed guides and rotating guides. The fixed guide has an advantage of being able to guide the tape stably, but avoids a large tape winding angle because the tape tension increases due to the friction caused by the contact with the tape. There is a need. Further, since the friction coefficient between the tape and the tape guide is different when the tape is stationary and when it is running, it is essentially disadvantageous for stabilizing the tape tension. On the other hand, the rotation guide has an advantage that the increase rate of the tape tension is small, but there is a problem that the tape guide becomes unstable due to the rotational runout of the roller and the slip in the tape width direction.

By the way, the recording density of the magnetic recording / reproducing apparatus has been remarkably increased, and accordingly, in the tape-shaped recording medium, smoothing of the surface, thinning of the surface, stabilization of running, and improvement of accuracy have been achieved. Further, as the recording capacity of the tape-shaped recording medium has increased, demands for operability such as searchability have increased, and further speeding up of tape running has been demanded. Therefore, in the magnetic recording / reproducing apparatus, it is necessary to make the tape running stability and the tape tension stability compatible, but as described above, both the fixed guide and the rotating guide essentially meet such requirements. Is difficult.

On the other hand, as a device that can meet such needs, there is a device in which compressed air is ejected from a small hole provided in the surface of the fixed guide, or a device in which the surface of the fixed guide is ultrasonically vibrated. Being developed. According to these tape guides, the tape guides have the characteristics that satisfy the above-mentioned requirements, but of these, the one that uses compressed air is inevitably a very large unit because it requires a compressor and piping. It is not suitable in terms of downsizing of the device. On the other hand, a device utilizing ultrasonic vibration can be made smaller.

Here, FIG. 7 shows a configuration example of a conventional tape guide utilizing ultrasonic vibration. In the figure,
The guide unit 110 is erected on the base 120 by the shaft 111 and the screw 116, and has a structure in which the upper flange 114, the pipe 112, and the lower flange 115 are press-fitted and fixed to the shaft 111. The guide pipe 113 that guides the tape 100 (see FIG. 9) on its outer peripheral surface is
It is held by the two projections 112a and 112b of the pipe 112. The vibrator 101 is composed of a laminated piezoelectric element in this example, and is configured to expand and contract when a voltage is applied. The shaker 101 has one end adhered and fixed to the surface of the guide pipe 113, and is held by a holding member 103 so as not to come into contact with the tape 100.

When an AC voltage is applied to the shaker 101, the expansion and contraction thereof causes the guide pipe 113 to vibrate. By vibrating the guide pipe 113 at an appropriate frequency, a resonance state as shown in FIGS. 8 and 9 can be obtained. This resonance mode has two nodes X and Y in the axial direction as shown in FIG. Further, as shown in FIG. 9, in the radial direction, an elliptical shape having a major axis in the vertical direction and an elliptical shape having a major axis in the horizontal direction are repeated in the figure, but the phase (a ) And phase (ke) are in-phase, and phase (e) and phase (s) are antiphase antinodes. Further, in the resonance mode, the outer peripheral surface of the guide pipe 113 is in a state shown in FIG. 11 when viewed in a surface development view.

In the above case, the two axial nodes X and Y (FIG. 8) are the two projections 112a and 112b of the pipe 112.
It corresponds to the position corresponding to, and thereby the vibration restraining action due to holding the guide pipe 113 can be eliminated, and the efficiency in this resonance mode can be increased. When the tape 100 is attached to the vibrating guide pipe 113 in this manner, the time during which the tape 100 and the tape 100 are in contact with each other is substantially reduced, and the friction can be remarkably reduced especially at rest.

[0008]

However, in the above-mentioned conventional guide unit 110, the guide pipe 113 that generates a standing wave at the splicing portion of the tape 100 and the guide pipe 113 are supported at the node of the resonance mode. Since it is configured by the rotating shaft 111, there are the following problems.

That is, (1) a mechanism for supporting the guide pipe 113 at the node of the resonance mode is required so as not to restrain the displacement of the resonating guide pipe 113. Guide pipe 113
In order to set the positions of the nodes X and Y in
High processing and assembly accuracy are required, and the guide pipe 113
In itself, high processing accuracy is required to obtain a predetermined shape dimension and surface roughness, which makes mass production processing difficult.

The resonance state of the guide pipe 113 is determined by the length, diameter, thickness and material of the guide pipe 113. In order to reduce the size of the tape guide, there is a method of reducing the length, diameter, etc. of the guide pipe 113. However, this increases the resonance frequency and promotes internal damping. Further miniaturization requires high processing accuracy, which eventually results in high cost and also deteriorates handleability of parts. Therefore, in the conventional structure, the degree of freedom for setting the resonance frequency must be reduced. In other words, there is a certain limit to such miniaturization and cost reduction.

(2) The ring-shaped guide pipe 113 having high rigidity is used as the resonance mode for producing the friction reducing effect.
In order to generate a standing wave with a predetermined amplitude by ultrasonic vibration, it is necessary to use a material such as a ceramic that has small internal damping and good vibration efficiency.

(3) Further, static electricity charged on the tape contact portion by the tape guide may attach dust around the tape or may adversely affect stable running of the tape. It is necessary to make the guide pipe 113 formed in 1) more conductive. Therefore,
There is no choice but to use expensive materials such as conductive ceramics.

An object of the present invention is to realize a tape guide mechanism which has a friction reducing effect by a resonance phenomenon of high efficiency and is suitable for downsizing at low cost.

In particular, an object of the present invention is to provide a tape guide mechanism capable of absorbing a machining error of the shaft and its rigidity or a mass system and a variation in assembly accuracy. Another object of the present invention is to provide a tape guide mechanism that can absorb variations in the rigidity of the shaft. A further object of the present invention is to provide a tape guide mechanism capable of absorbing the vibration balance error of the tape splicing member.

[0015]

The tape guide mechanism of the present invention has a shaft having one end fixed and a tape attachment member fixed to a predetermined portion of the shaft, and vibrating means for vibrating the shaft. Thus, the tape splicing member is vibrated and displaced. In particular, the tape splicing member has means for changing the rigidity of the shaft.

Further, in the tape guide mechanism of the present invention, the shaft is formed so as to have high rigidity on the fixed portion side. In particular, the shaft has a cross-sectional shape on the fixed portion side set to be larger than that on the free end side.

Further, in the tape guide mechanism of the present invention, a constant mass system is provided on the free end side of the shaft, and the supporting position of this mass system is adjustable.

[0018]

According to the present invention, first, a means for changing the rigidity of the shaft is provided, the resonance mode of the tape splicing portion is set by the rigidity of the fixed part of the shaft, and the other part of the shaft is set. It retains its resonance mode. That is, a desired resonance mode can be effectively obtained by having a part that is involved in setting the resonance mode of the shaft and a part that holds the part.

Further, according to the present invention, the rigidity is high on the fixed part side of the shaft, that is, the cross-sectional shape of the fixed part side is set large,
It is possible to absorb changes in setting parameters on the fixed part side of the shaft.

Further, according to the present invention, the supporting position of the mass system of the shaft can be adjusted, and by adjusting the supporting position, the vibration balance of the tape splicing member can be finely adjusted. .

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the tape guide mechanism of the present invention will be described with reference to FIGS. In this example, the tape guide portion has one end 13a fixed to the base 20 and a support shaft 13 having the mass system 12 at the other free end 13b, and a guide pipe 14.
The guide pipe 14 is supported by the central portion 13c of the support shaft 13, and is fixed vertically to the guide pipe 14 so that the vibrator 16 does not come into contact with the tape. The vibrator 16 is configured by using a laminated piezoelectric element. Further, in FIG. 1, reference numerals 12a and 17 denote flange portions for suppressing the vertical shift of the tape, and by forming the flange portion 17 with a light material, the vibration mode of the tape guide described later is affected. It is configured not to give.

When an AC voltage is applied to the vibrator 16, the support shaft 13 vibrates. In this case, by vibrating at a frequency outside the appropriate audible band, for example, as shown in FIG.
A resonance state as shown in can be created. next,
The principle of forming this resonance state will be described with reference to FIG.

Here, first, when the tape guide unit 10 is approximated by a simple mechanical model, it has two mass systems or mass parts 22 and 24, and a cantilever having one end fixed ((A) in FIG. 2). It can be modeled in the form (ie a beam model with a two mass system). In this beam model, the mass system 12 on the free end side of FIG.
And the guide pipe 14 corresponds to the mass system 24. In addition, in the cantilever beam in which the support shaft 13 of FIG. 1 corresponds to the beam 23, and the beam 23 is fixed by the fixed end portion 23 a, the mass systems 22 and 24 are connected to the tip portion 23 b of the beam 23.
And the central portion 23c of the beam.

Considering the resonance state of the beam 23, in the model shown in FIG. 2A, due to the rigidity of the two mass systems 22 and 24 and the beam 23, the two mass systems 22, 24.
Are considered to be a first-order resonance mode (a) in which the resonance occurs in the same phase, and a second-order resonance mode (c) in which the mass systems 22 and 24 resonate in the opposite phase. In the resonance mode (c), the beam 23
The mass system 22, so that the displacement of the tip portion 23b of the
24 and the supporting position of the mass system 24 (the central portion 23
The resonance state can be realized by setting the position such that c) has the maximum amplitude. If appropriate parameters are set by such a design method, as shown in FIG.
The support position of the guide pipe 14 (center portion 13c) with both ends 13a and 13b of the support shaft 13 as shown in FIG.
Causes a resonance state with the belly.

In this resonance mode (c), since the guide pipe 14 is supported at the position of the antinode (maximum amplitude) of the vibration of the support shaft 13, it follows the antinode (central portion 13c) of the support shaft 13, Upper part 14a and lower part 14b of the guide pipe 14
Translational vibrations in which the phase of the displacement is in phase. As described above, in addition to the tape guide unit 10 being small in size, since the antinode of resonance of the support shaft 13 is used, a large amplitude can be obtained with a small amount of energy.
The friction reducing effect can be easily obtained.

Similarly, by vibrating the exciter 16 at a frequency outside the appropriate audible range, a resonance state as shown in FIG. 3B can be created. In the third resonance mode (d) (see FIG. 2), the guide pipe 14
Rotational vibration is obtained in which the upper part 14a and the lower part 14b are displaced in opposite directions with respect to the support shaft 13.

In the first-order resonance mode (a), the position of the center of gravity of the entire model moves, whereas in the second-order resonance mode (c) and the third-order resonance mode (d). Since the two mass systems 22 and 24 are displaced in opposite phases,
The amount of movement of the center of gravity of the entire model is smaller than that in the first-order resonance mode (a). Therefore, in the resonance mode (C) and the resonance mode (D), the tape guide at that time has a large amplitude in translational vibration (C) and rotational vibration (D).
do. In this case, the contact area between the tape and the guide pipe 14 is small, so that a large friction reducing effect can be obtained with a small amount of energy.

By the way, in the tape guide mechanism utilizing the ultrasonic vibration according to the above-mentioned embodiment, a desired resonance mode can be obtained due to the machining error of the support shaft 13 and its rigidity or the mass system and the variation of the assembly accuracy. May not be. Further, in adjusting the tape running at the time of assembly, the tape guide unit 1 is provided in order to apply a regulation force in the tape width direction.
Although 0 is finely adjusted up and down, the desired resonance mode may not be obtained in some cases due to the change in the axial length due to the fine adjustment. In such a case, it becomes difficult to vibrate the tape guide efficiently, and an effective tape friction reducing effect cannot be expected.

A further embodiment of the tape guide mechanism according to the present invention will be described with reference to FIGS.

4 and 5 are an external view and a sectional view, respectively, of the tape guide unit 10 'according to this embodiment. In the figure, the tape guide portion is constituted by a support shaft 13 having one end 13a fixed to a base 20 and a mass system 12 at the other free end 13b, and a guide pipe 14 as a tape splicing member. To be done. The guide pipe 14 is supported by the central portion 13c of the support shaft 13, and in the direction perpendicular to the guide pipe 14,
The vibrator 16 is fixed so as not to contact the tape. The vibrator 16 is configured by using a laminated piezoelectric element.

Further, 17 and 18 are flanges for suppressing the vertical displacement of the tape. By forming these flanges 17 and 18 with a light material, the vibration mode of the tape guide described later is described. Is configured to not affect.

The mass system 12 and the support shaft 13 are the support shaft 13
The free end 13b of the mass system 12 is screwed, and the supporting position of the mass system 12 can be adjusted up and down. Further, the support shaft 13 has a two-step structure having small diameter portions 13e and 13g and a large diameter portion 13f by a step portion 13d. As described above, by providing the support shaft 13 with the large diameter portion and the small diameter portion, the rigidity of the large diameter portion 13f is improved.
The rigidity can be changed so as to be higher than the rigidity of e and 13g. As a result, as shown in FIG. 6, it is possible to make the portion having a large diameter less likely to vibrate than the portion having a small diameter.

When adjusting the tape guide in the tape guide mechanism constructed as described above, first, the support shaft 13 of the tape guide unit 10 'is provided in order to apply the regulation force in the tape width direction when adjusting the tape running. Rotate it
Adhesive fixing is performed with the screw portion 13h at the appropriate rotation position.
Next, an AC voltage is applied to the vibrator 16, and the supporting position of the mass system 12 at the free end 13b of the supporting shaft 13 is adjusted up and down so that a desired resonance mode can be obtained at this time. Then, after this adjustment, the mass system 12 is adhesively fixed to the support shaft 13.

When the guide unit 10 'is adjusted up and down, the axial length changes. Even if this shaft length changes in millimeter order, as described above, the support shaft 13
Has a two-step structure with a large diameter, so that the rigidity of the fixed portion is increased, and the vibration mode to be set is mainly caused by the deformation of the small diameter portions 13e, 13g. For this reason,
In the mechanical model shown in (1), the axial length itself which can be involved in setting the resonance mode does not change even in the resonance mode (c) and the resonance mode (d). Therefore, even if the setting parameter of the fixed part of the support shaft 13, that is, the axial length of the part is changed, it can be considerably reduced to the extent that it itself contributes to or affects the setting of the vibration mode in the tape splicing part. . As a result, the tape running adjustment can be performed easily and accurately.

On the other hand, in the case where accuracy variations during machining are unavoidable, the positions of the mass system 22 on the free end 23b side are changed to change the mass system 22 and the mass system 24 in the dynamic model shown in FIG. Some tuning can be done by changing the coupling stiffness of the supporting shaft. For example, in the case where the mass system 24 should vibrate so as to be the antinode of the beam 23, the mass system 24 may cause the beam 23 to vibrate due to a processing error or the like.
In the vibration mode set to the fixed end portion 23a side of the antinode position of the beam 23, the rigidity of the beam portion 23e on the free end side of the beam 23 becomes relatively small. In such a case, by moving the mass system 22 toward the fixed end portion 23a side, the beam portion 23e
Therefore, the rigidity of the mass system 24 can be increased, so that the mass system 24 can be oscillated at the antinode position of the beam 23 by adjusting the movement of the mass system 22.

Consider the tuning action in the above-mentioned dynamic model for the tape guide unit 10 '. For example, in FIG. 6, when the free end 13b side of the support shaft 13 is longer than the original one, at this time, the displacement amount of the upper portion 14a (see FIG. 5) of the guide pipe 14 becomes larger than the displacement amount of the lower portion 14b. Vibrate. In such a case, by moving the mass system 12 to the fixed end side, a translational motion in which the displacement amounts of the upper portion 14a and the lower portion 14b of the guide pipe 14 are equal to each other is obtained, and therefore, the influence of the processing error is substantially absorbed. can do. On the other hand, when the free end 13b side of the support shaft 13 is shorter than the original one, by moving the mass system 12 to the free end 13b side, the influence of the processing error can be substantially absorbed.

In the above case, the example of the resonance mode (c) of FIG. 2 in which the antinode of the support shaft 13 at the time of vibration becomes the support position of the guide pipe 14 has been described. In the case of the resonance mode (d) of FIG. Can also perform the same tuning action as above.

Although the present invention has been described with reference to the preferred embodiments, various modifications and the like are possible within the scope of the present invention. For example, in order to thicken the cross-sectional shape of the fixed portion of the support shaft 13, a multi-step structure with three or more steps, a tapered shape, or the like may be adopted,
It is possible to obtain the same effect as that of the above-mentioned embodiment. Also, an example of the screw bonding method has been described as the position fine adjustment mechanism of the mass system 12 at the free end 13b of the support shaft 13, but the mass system 12 is attached to the support shaft 13 in a fitting manner, and the mass system 12 is appropriately adjusted. It may be screwed at the position.

[0039]

As described above, according to the present invention, first, the vibrating means for vibrating the shaft is provided with the shaft having one end fixed and the tape attachment member fixed to a predetermined portion of the shaft. By changing the rigidity of the shaft in the tape guide mechanism in which the tape splicing member is oscillated and displaced, changes in setting parameters during assembly and variations in finish during processing are effectively absorbed and reduced. be able to.

Further, according to the present invention, the shaft length is changed when the tape running is adjusted by increasing the rigidity on the fixed portion side of the shaft, that is, by setting the sectional shape on the fixed portion side of the shaft to be large. Even in this case, the vibration mode of the tape splicing portion can be maintained and a desired high friction reducing effect can be realized.
Furthermore, according to the present invention, by making it possible to adjust the supporting position of the mass system on the free end side of the shaft, the vibration balance of the tape splicing member can be finely adjusted, and variations during processing can be effectively absorbed. And can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a tape guide mechanism of the present invention.

FIG. 2 is a diagram showing an example of vibration modes in a mechanical model of a tape guide mechanism.

FIG. 3 is a diagram showing an example of a vibration mode in an embodiment of the tape guide mechanism of the present invention.

FIG. 4 is an external perspective view of another embodiment of the tape guide mechanism according to the present invention.

FIG. 5 is a sectional view of another embodiment of the tape guide mechanism according to the present invention.

FIG. 6 is a diagram showing an example of a vibration mode in another embodiment of the tape guide mechanism according to the present invention.

FIG. 7 is a cross-sectional view of a conventional vibrating tape guide.

FIG. 8 is a diagram showing an example of a resonance mode in a conventional vibrating tape guide.

FIG. 9 is a partial plan view showing an example of a resonance mode in a conventional vibrating tape guide.

FIG. 10 is a development view of a guide pipe surface in a resonance mode in a conventional vibrating tape guide.

[Explanation of symbols]

 10 Tape guide unit 12 Mass system 13 Support shaft 13a One end 13b Free end 13c Central part 13d Step part 13e Small diameter part 13f Large diameter part 13g Small diameter part 13h Screw part 14 Guide pipe 16 Exciter 17 Flange part 18 Flange part 20 Base 22 Mass system 23 Beam 24 Mass system

Claims (4)

[Claims] 1. A shaft having one end fixed thereto and a tape attachment member fixed to a predetermined portion of the shaft, wherein the tape attachment member is vibrated and displaced by vibrating means for vibrating the shaft. The tape guide mechanism according to claim 1, further comprising means for changing the rigidity of the shaft. 2. The tape guide mechanism according to claim 1, wherein the shaft is formed so as to have high rigidity on the fixed portion side. 3. The tape guide mechanism according to claim 1, wherein the shaft has a cross-sectional shape on the fixed portion side set to be larger than that on the free end side. 4. The tape guide mechanism according to claim 1, wherein a constant mass system is provided on a free end side of the shaft, and a supporting position of the mass system is adjustable. .