JPH05342689A - Tape winding diameter detecting device - Google Patents

Abstract

PURPOSE:To obtain the winding diameter of a reeled tape without rotating a reel. CONSTITUTION:A sinusoidal wave generation part 5 generates a sinusoidal wave signal S1 with a prescribed frequency and a prescribed amplitude. An actuator driving part 6 receives the sinusoidal signal S1 and drives an actuator 3. The actuator 3 gives vibration in a constant direction to a reel shaft 2. A displacement detection part 7 receives the output signal of a displacement sensor 4 and detects the displacement amplitude (xo) or the displacement speed amplitude (vo) of the reel at a normal state. An amplitude ratio calculation part 8 receives the sinusoidal signal S1 and obtains the driving force amplitude (fo) of the actuator driving part 6 then calculates an amplitude ratio (xo/fo or vo/fo). A tape winding diameter calculation part 9 calculates the tape winding diameter based on the amplitude ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape winding diameter detecting device, and more particularly to a tape winding diameter detecting device for calculating the outer diameter of a tape wound on a reel of a magnetic recording / reproducing device or the like.

[0002]

2. Description of the Related Art In a conventional tape winding diameter detecting device, a pulse generator for generating a pulse in proportion to a rotation speed is attached to a rotation shaft of a reel, and the pulse generated within a fixed time is counted to measure the rotation speed of the reel. The outer diameter of the tape wound on the reel is calculated by obtaining

[0003]

In the above-mentioned conventional tape winding diameter detecting device, the outer diameter of the tape is calculated by obtaining the rotation speed of the reel. Therefore, in order to obtain the outer diameter of the tape,
It is necessary to rotate the reel by operating the magnetic recording / reproducing device or the like.

It is an object of the present invention to provide a tape winding diameter detecting device which can determine the winding diameter of a tape wound on a reel without rotating the reel.

[0005]

A tape winding diameter detecting device of a first invention is a tape winding diameter detecting device for detecting a winding diameter of a tape wound on a reel placed on a reel shaft,
Means for imparting a constant direction sine wave vibration to the reel shaft,
A means for detecting a displacement amplitude or a displacement speed amplitude of the reel in a steady state of the sine wave vibration, and a means for calculating a winding diameter of the tape based on the displacement amplitude or the displacement speed amplitude detected by the detecting means. Is configured.

A tape winding diameter detecting device of a second invention is a tape winding diameter detecting device for detecting a winding diameter of a tape wound on a reel placed on a reel shaft, wherein the reel shaft has an arc direction of a predetermined radius. And a means for detecting the angular displacement amplitude or the angular displacement velocity amplitude of the reel in the steady state of the sinusoidal vibration, and the angular displacement amplitude or the angular displacement velocity amplitude detected by the detecting means. And means for calculating the winding diameter of the tape.

[0007]

The present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a first embodiment of the present invention. Here, the reel 1 on which the tape is wound is placed on the reel shaft 2, and the reel shaft 2 is attached with an actuator 3 for vibrating in a direction perpendicular to the shaft.
The displacement sensor 4 is provided to detect the displacement of the reel 1.

Now, let m be the total mass of the portion vibrated by the actuator 3, that is, the reel and reel shaft around which the tape is wound, and the force applied to this total mass m is u.
(T) and the displacement of the reel is x (t), the equation (1) is established.

[0010]

However, B is a coefficient mainly relating to viscous friction, and K is
Is a coefficient mainly related to the actuator.

Here, when the equation (1) is Laplace transformed,
Equation (2) is obtained. In addition, s represents the Laplace operator. x (s) = {bo / (s (s + ao))}. u (s) (2) However, ao = B / m, bo = K / m (3).

Now, u (t) = fo · sin (ωt) ...
(4) and the amplitude of the reel displacement x (t) in the steady state is xo, the equation (5) is established.

[0014]

When xo / fo = co is set, the equation (6) is obtained from the equations (3) and (5).

[0016]

When the mass of the reel 1 on which the tape is wound is mt and the mass of the portion excluding the reel 1 is mc, m = mt + mc (7)

Further, when the tape density is ρ, the tape winding radius is R, the reel frame radius of the reel hub is Rh, and the mass of the reel hub is mh, the mass mt of the reel including the tape is expressed by the formula (8). Can be expressed as mt = πρbo (R ² −Rh ² ) + mh (8) Therefore, from equations (6), (7) and (8), the tape winding radius R
Equation (9) is obtained by obtaining

[0019]

That is, if a sinusoidal vibration is applied to the reel and the displacement amplitude of the reel in the steady state is detected, the tape winding radius R can be calculated using the equation (9).

By the way, paying attention to the displacement speed of the reel when the reel is vibrated and the displacement speed is v (t), the equation (10) is established.

[0022]

When the equation (10) is Laplace transformed,
Equation (11) is obtained. v (s) = {bo / (s + ao)} · u (s) (11) Here, when the amplitude of the reel displacement speed v (t) in the steady state is vo, the expression (12) is established.

[0024]

Similarly, when vo / fo = c1 is set and the tape winding radius R is obtained, the equation (13) is obtained.

[0026]

That is, if a sinusoidal vibration is applied to the reel and the displacement velocity amplitude of the reel in the steady state is detected, the tape winding radius R can be calculated using the equation (13).

The first embodiment of the present invention is configured to operate based on the above-mentioned principle. That is, FIG.
In, the sine wave generator 5 generates a sine wave signal S1 having a predetermined frequency and amplitude. The actuator drive unit 6 is
Upon receiving the sine wave signal S1, the actuator 3 is driven.
The actuator 3 gives a vibration to the reel shaft 2 in a direction perpendicular to the reel shaft 2.

The displacement detector 7 receives the output signal of the displacement sensor 4 and detects the reel displacement amplitude xo or the displacement velocity amplitude vo in the steady state. The amplitude ratio calculator 8 receives the sine wave signal S1 to obtain the driving force amplitude fo of the actuator driver 6, and calculates the amplitude ratio (xo / fo or vo / f).
o) is calculated. The tape winding diameter calculation unit 9 calculates the tape winding radius R by the above-described formula (9) or formula (13).

FIG. 2 is a diagram showing a second embodiment of the present invention, (a) is a diagram showing the entire structure, and (b) is a top view showing the positional relationship between reels and actuators. The same components as those shown in FIG. 1 are designated by the same reference numerals.

Here, the reel 1 on which the tape is wound is placed on the reel shaft 2. This reel shaft 2 has a joint 11
It is joined to the actuator 10 via the, and vibrates in an arc direction by the actuator 10. Further, the actuator 10 has a displacement sensor 1 for detecting a rotational angle displacement.
2 is attached.

Now, the mass of the reel 1 including the tape is m
Let t be L, the length of the joint 11 be L, the inertia around the rotation axis of the actuator 10 excluding the reel 1 be J, the rotational force be z (t), and the angular displacement of the reel be θ (t). To establish.

[0033]

However, B is a coefficient mainly relating to viscous friction, and K is
Is a coefficient mainly related to the actuator.

When the equation (14) is Laplace transformed, the equation (15) is obtained. θ (s) = {b1 / (s (s + a1))} · z (s) (15) where a1 = B / (J + mt · L ² ) and b1 = K / (J
+ Mt · L ² ) ... (16).

Now, adopting a sine wave input as z (t), z (t) = ro.sin (ωt) (17), and the amplitude value of the angular displacement in the steady state is θo, θ
If o / ro = c2, then equation (18) holds.

[0037]

Here, the mass mt of the reel containing the tape
Can be expressed by equation (8), and thus equation (19) for obtaining the tape winding radius R is obtained from equations (8) and (18).

[0039]

That is, if a sinusoidal vibration in the arc direction is applied to the reel and the angular displacement amplitude of the reel in a steady state is detected, the tape winding radius R can be calculated using the equation (19).

By the way, paying attention to the angular velocity of the reel when the sinusoidal vibration in the arc direction is applied to the reel, the angular velocity is Ω.
If it is (t), Formula (20) will be materialized.

[0042]

Similarly, when the equation (20) is Laplace transformed, the equation (21) is obtained. Ω (s) = {b1 / (s + a1)} · z (s) (21) Here, when the reel displacement speed amplitude in the steady state is Ωo and Ωo / ro = c3, the formula (22) is established. To do.

[0044]

Therefore, the equation (23) for obtaining the tape winding radius R is obtained from the equations (8) and (22).

[0046]

That is, if a sinusoidal vibration in the arc direction is applied to the reel and the angular velocity amplitude of the reel in the steady state is detected, the tape winding radius R can be calculated using the equation (23).

The second embodiment of the present invention is constructed based on the above-mentioned principle.

In FIG. 2, the sine wave generator 5 generates a sine wave signal S1 having a predetermined frequency and amplitude. The actuator drive unit 6 receives the sine wave signal S1 and drives the actuator 10. The actuator 10 gives vibration to the reel shaft 2 in an arc direction via the joint 11.

The displacement detector 13 receives the output signal from the displacement sensor 12 which detects the rotational angular displacement, and detects the angular displacement amplitude θo or the angular velocity amplitude Ωo of the reel in the steady state. The amplitude ratio calculation unit 8 receives the sine wave signal S1 to obtain the rotational force amplitude ro of the actuator drive unit 6, and calculates the amplitude ratio (θo / ro or Ωo / ro). The tape winding diameter calculation unit 9 uses the equation (19) or the equation (2) described above.
The tape winding radius R is calculated according to 3).

In this embodiment, the displacement direction of the reel is perpendicular to the reel axis. However, even if the reel is displaced in the direction parallel to the reel axis in consideration of the resonance frequency of vibration, the same is true. It is obvious that the tape winding diameter can be detected.

[0052]

As described above, according to the first aspect of the present invention, the reel wound with the tape is placed on the reel shaft, and the reel shaft is subjected to sinusoidal vibration in a constant direction to displace the reel in a steady state. By detecting the amplitude or the displacement velocity amplitude and calculating the tape winding diameter, the winding diameter of the tape wound on the reel can be obtained without rotating the reel.

According to the second aspect of the present invention, the reel wound with the tape is placed on the reel shaft, and the reel shaft is subjected to sinusoidal vibration in a circular arc direction of a predetermined radius so that the angular displacement amplitude of the reel in the steady state or By detecting the angular velocity amplitude and calculating the tape winding diameter, the same effect as that of the first invention can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a second embodiment of the present invention, (a)
[Fig. 3] is a diagram showing an overall configuration, and Fig. 6B is a top view showing a positional relationship between reels and actuators.

[Explanation of symbols]

 1 Reel 2 Reel shaft 3,10 Actuator 4,12 Displacement sensor 5 Sine wave generation part 6 Actuator drive part 7,13 Displacement detection part 8 Amplitude ratio calculation part 9 Tape winding diameter calculation part 11 Joint

Claims (2)

[Claims] 1. A tape winding diameter detecting device for detecting a winding diameter of a tape wound on a reel placed on a reel shaft, and means for applying a sine wave vibration in a fixed direction to the reel shaft, and the sine wave vibration. And means for detecting the displacement amplitude or displacement speed amplitude of the reel in the steady state, and means for calculating the winding diameter of the tape based on the displacement amplitude or displacement speed amplitude detected by the detection means. Tape winding diameter detector. 2. A tape winding diameter detecting device for detecting a winding diameter of a tape wound on a reel mounted on a reel shaft, said means for applying a sinusoidal vibration in a circular arc direction having a predetermined radius to said reel shaft, Means for detecting the angular displacement amplitude or angular displacement velocity amplitude of the reel in a steady state of sinusoidal vibration, and means for calculating the tape winding diameter based on the angular displacement amplitude or angular displacement velocity amplitude detected by the detecting means. A tape winding diameter detecting device comprising: