JPH05128661A - Impedance roller device - Google Patents

Abstract

PURPOSE:To enable arbitrary setting of the center of the suppressing frequencies of vibrations and to enable the removal of the longitudinal vibrations of a magnetic tape by connecting a 2nd rotating part via an elastic connecting member to a 1st rotating part and generating the torsional vibrations as a whole. CONSTITUTION:The 2nd rotating part 4 is elastically connected via the elastic connecting part 3 consisting of a lightweight elastic member consisting of, for example, a polyamide resin to the 1st rotating part 2 which is fixed to a supporting part 1 and rotates integrally with the supporting shaft part 1 as the magnetic tape travels. The top end of the supporting shaft part 7 is pressed by a thrust retainer 9. This 2nd rotating part 4 is rotated in follow up to the rotation of the 1st rotating part 2 so as to generate the torsional vibrations as a whole. As a result the arbitrary setting of the center of the suppression frequencies of the vibrations is facilitated and the specific frequencies of the longitudinal vibrations of the magnetic tape occurring in the rotating frequencies of, for example, a cylinder head are removed.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impedance roller device used for carrying a magnetic tape for a VTR, for example.

[0002]

2. Description of the Related Art As shown in FIG. 7, there is shown a magnetic tape transport device for recording / reproducing a VHS system VTR. In this magnetic tape transport device, the magnetic tape C is pulled out from the supply reel B of the VHS cassette A, passed through an impedance roller D for vibration removal, and then wound around the cylinder head E. Furthermore, magnetic tape C
Is conveyed at a constant speed by the pinch roller F and the capstan G, and is taken up by the take-up reel H. Since the impedance roller D is configured as described above, a relatively large inertia is imparted to the impedance roller D so that the inertial energy of the impedance roller D against the longitudinal vibration of the magnetic tape C (vibration in the longitudinal direction of the magnetic tape C) is increased. By absorbing and releasing, it has the effect of suppressing longitudinal vibration.

By the way, the impedance roller D has a mechanism in which the magnetic tape C contacts the surface indicated by r and the impedance roller D rotates, as shown in FIG. In this figure, the rotating portion I includes a rotating roller J,
It is composed of an oil-impregnated bearing K and a thrust retainer L.
The rotating portion I is pivotally supported by a support shaft M, and the support shaft M is erected on a base N. In the impedance roller D having such a configuration, the oil-impregnated bearing K in the radial direction and the thrust retainer L in the thrust direction make it possible to prevent increase of loss torque as much as possible, and vibration of the magnetic tape C in a wide range can be prevented. It was effective against frequency.

However, there is a limit to the vibration suppression level by the impedance roller D, and the center of the vibration suppression frequency cannot be set arbitrarily. Particularly, in the case of the VHS system VTR, since the longitudinal vibration of the magnetic tape C is dominated by the higher-order component whose basic component is 30 Hz which is the rotation frequency of the cylinder head P,
In particular, it is desired to suppress this component.

[0005]

As described above, in the conventional impedance roller device, the vibration suppression level is limited, and the center of the vibration suppression frequency cannot be set arbitrarily. In particular, in the case of the VHS system VTR, since the longitudinal vibration of the magnetic tape is dominated by a high-order component whose fundamental component is 30 Hz which is the rotation frequency of the cylinder head, it is particularly desired to suppress this component. However, it was difficult with the conventional impedance roller device.

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an impedance roller device capable of easily suppressing longitudinal vibration of a magnetic tape with a simple structure. [Constitution of Invention]

[0007]

SUMMARY OF THE INVENTION According to the present invention, a first rotating portion fixed to a support shaft portion and integrally rotated with a support shaft portion as a magnetic tape travels, is provided with a second rotation via an elastic connecting portion. The parts are elastically connected, and the second rotating part is rotated following the rotation of the first rotating part so that torsional vibration is generated as a whole.

[0008]

With the impedance roller device having such a structure, it becomes easy to arbitrarily set the center of the vibration suppression frequency, and for example, a specific frequency such as longitudinal vibration of the magnetic tape due to the rotation frequency of the cylinder head can be set. Vibration can be removed.

[0009]

An embodiment of the present invention will be described in detail below with reference to the drawings.

1 and 2 show an impedance roller device of this embodiment. This impedance roller device includes a support shaft portion 1, a first rotating portion 2 coaxially attached to the support shaft portion 1, and an elastic connecting portion coaxially attached to the support shaft portion 1 together with the first rotating portion 2. 3 and a second elastically connected to the first rotating part 2 via the elastic connecting part 3.
It consists of a rotating part 4. Thus, the support shaft portion 1 includes a flat plate-shaped base plate 1a, a cylindrical housing 5 that is integrally erected on the base plate 1a, and a sintered oil-impregnated bearing that is press-fitted and fixed to the upper and lower positions of the inner wall of the housing 5. 6, 6 and a supporting shaft 7 rotatably supported by the sintered oil-impregnated bearings 6, 6 in a radial manner, fixed by caulking to the bottom of the housing 5, and supported by the sintered oil-impregnated bearings 6, 6. A thrust bearing 8 that supports the support shaft 7 as a thrust shaft and a thrust retainer 9 that presses the upper end of the support shaft 7 are provided. The outer peripheral portion of the housing 5 is formed into a tapered surface having a small upper end. On the other hand, the first rotating portion 2 is made of a metal member, such as copper, which is coaxially press-fitted and fixed to a substantially midway portion of the support shaft 7 near the housing 5, and the main body 10 is directly fixed to the support shaft 7. And a loose fitting portion 11 provided under the main body portion 10 and loosely inserted in the outer peripheral portion of the housing 5.
And a collar portion 12 provided on the upper portion of the main body portion 10. A circular hole 13 with a bottom is formed in the center of the collar 12.
Has been drilled. The outer peripheral surface of the loose fitting portion 11 is a sliding contact surface 11 a of the magnetic tape C. On the other hand, the elastic connecting portion 3 is made of a lightweight elastic member, such as polyamide resin, which is press-fitted and fixed to the upper end portion of the support shaft 7. Also,
The elastic connecting portion 3 includes a cylindrical press-fitting portion 16 directly press-fitted and fixed to the support shaft 7, a ring-shaped thin-walled portion 17 extending at a right angle in the middle of the press-fitting portion 16, and the thin-walled portion. Part 1
The second rotating portion 4 is connected to the outer periphery of the second rotating portion 4 and has a cylindrical second rotating portion mounting portion 18 into which the second rotating portion 4 is press fitted. In addition,
A part of the press-fitting portion 16 is loosely inserted in the circular hole 13. Further, the second rotating portion 4 is made of a metal member such as copper. Therefore, the second rotating portion 4 is connected to the elastic connecting portion 3
Rigidity is relatively large compared to. The spring constant of the elastic connecting portion 3, the moment of inertia of the first rotating portion 2 and the inertia moment of the second rotating portion 4 are set so as to satisfy the conditions described later. Next, the operation of the impedance roller device of this embodiment having the above configuration will be described.

First, the magnetic tape C is pulled out from the supply reel of the VHS cassette, passed through the impedance roller device of this embodiment, and then wound and wound around the cylinder head. Further, the magnetic tape C is conveyed at a constant speed by a pinch roller and a capstan and is wound by a take-up reel. At this time, the magnetic tape C is
While running in sliding contact with the sliding contact surface 11a of the rotating part 2, the running part 2 runs in its longitudinal direction. Along with this, the first rotating portion 2 rotates about the support shaft 7 as a rotating shaft. Then, the elastic connecting portion 3 is connected via the support shaft 7.
Also rotates. However, since the elastic connecting portion 3 is made of an elastic member, the first rotating portion 2 and the second rotating portion 4 which are elastically connected to each other via the elastic connecting portion 3 have the second rotating portion 4 As a result, the rotation delay occurs with respect to the first rotating portion 2, and as a result, torsional vibration is generated. That is, the second rotating part 4 and the first rotating part 2 have the natural frequency ω expressed by the following equation (1). ω = [(1 / I ₁ + 1 / I ₂ ) K] ^1/2 ……… (1)

However, I ₁ is the moment of inertia of the first rotating portion 2, I ₂ is the moment of inertia of the second rotating portion 4, and K is the spring constant of the elastic connecting portion 3. By the way, as described above, the rotation of the first rotating portion 2 is affected by the longitudinal vibration of the magnetic tape C. In particular, in the case of the VHS system VTR, as shown in FIG. 3, the longitudinal vibration of the magnetic tape C is dominated by a high-order component whose basic component is 30 Hz which is the rotation frequency of the cylinder head. Therefore, according to the equation (1), the spring constant of the elastic connecting portion 3 and the first rotating portion 2 are set so that the natural frequency ω of the second rotating portion 4 and the first rotating portion 2 coincides with the longitudinal vibration of the magnetic tape C. And the inertia moment of the second rotating portion 4 are adjusted. As a result, the actual magnetic tape C
When running in the longitudinal direction while sliding on the sliding contact surface 11a of the first rotating portion 2, the first rotating portion 2 vibrates in the vicinity of 30 Hz as shown by the solid line in FIG. On the other hand, the second rotating portion 4 vibrates at substantially the same frequency as and opposite phase to the first rotating portion 2, as indicated by the broken line in FIG. As a result, the vibrations of the first rotating part 2 and the second rotating part 4 cancel each other out, and the impedance roller device as a whole eliminates the vibrations due to the rotation frequency of the cylinder head, as shown in FIG.

As described above, in this embodiment, the elastic connecting portion 3 is fixed to the first rotating portion 2 which is fixed to the supporting shaft portion 1 and rotates integrally with the supporting shaft portion 1 as the magnetic tape C runs.
The second rotating portion 4 is elastically connected via the second rotating portion 4, and the second rotating portion 4 is rotated following the rotation of the first rotating portion 2 so that torsional vibration is generated as a whole. It becomes easy to set the center of the suppression frequency of
For example, it is possible to eliminate vibration of a specific frequency such as longitudinal vibration of the magnetic tape due to the rotation frequency of the cylinder head.

The present invention is not limited to the above embodiment, but may be, for example, one as shown in FIG. That is, in this other embodiment, the support shaft portion 1 and the first rotating portion 2 are the same as those in the first embodiment, but the second rotating portion 40 made of metal and having high rigidity is directly attached to the support shaft 7. It is rotatably inserted. The elastic connecting portion 41 made of a compression torsion spring is wound around the support shaft 7. One end of the elastic connecting portion 41 is attached to the first rotating portion 2 by the locking pin 42.
Is locked at the upper end of the. On the other hand, the other end of the elastic connecting portion 41 is locked to the lower end of the second rotating portion 40 by the locking pin 42. Therefore, the first rotating portion 2 and the second rotating portion 40 are elastically connected to each other via the elastic connecting portion 41 provided therebetween.

Also in the impedance roller device having such a configuration, the first rotating portion 2 and the second rotating portion 40 which are elastically connected to each other through the elastic connecting portion 41 have the second rotating portion.
As a result of the rotation portion 40 delaying the rotation with respect to the first rotation portion 2, torsional vibration is generated as a whole. Therefore, also in the case of this embodiment, it becomes easy to arbitrarily set the center of the vibration suppression frequency, and it is possible to eliminate the vibration of a specific frequency such as the longitudinal vibration of the magnetic tape due to the rotation frequency of the cylinder head. Becomes Further, the elastic connecting portion may be appropriately selected from rubber, spiral spring, conical spring, and the like.

[0016]

According to the present invention, the first rotating portion fixed to the supporting shaft portion and integrally rotating with the supporting shaft portion along with the running of the magnetic tape is elastically connected to the second rotating portion via the elastic connecting portion. Since the second rotating portion is rotated following the rotation of the first rotating portion to generate torsional vibration as a whole, it is easy to arbitrarily set the center of the vibration suppression frequency. Therefore, it becomes possible to eliminate vibration of a specific frequency such as longitudinal vibration of the magnetic tape due to the rotation frequency of the cylinder head.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of an impedance roller device according to an embodiment of the present invention.

FIG. 2 is a perspective view of an impedance roller device according to an embodiment of the present invention.

FIG. 3 is an operation explanatory view showing longitudinal vibration of the magnetic tape in the impedance roller device of the embodiment of the present invention.

FIG. 4 is an operation explanatory view of the impedance roller device according to the embodiment of the present invention.

FIG. 5 is an operation explanatory view of the impedance roller device according to the embodiment of the present invention.

FIG. 6 is a sectional view showing the structure of an impedance roller device according to another embodiment of the present invention.

FIG. 7 is an explanatory diagram of a conventional magnetic tape transport device.

FIG. 8 is a cross-sectional view showing a configuration of a conventional impedance roller device.

[Explanation of symbols]

1: Spindle part, 2: First rotating part, 3: Elastic connecting part, 4: Second rotating part, 7: Spindle.

Claims (3)

[Claims] 1. A first rotating part having an outer peripheral surface with which a tape-shaped running body is in sliding contact, a spindle that is fixed coaxially with the first rotating part and that rotates together with the first rotating part as the running body runs. A supporting shaft portion having a bearing for supporting the supporting shaft, and a second rotating portion provided coaxially with the first rotating portion,
An impedance roller device, comprising: an elastic connecting part that elastically connects the first rotating part and the second rotating part so that the second rotating part follows the rotation of the first rotating part. 2. The impedance roller device according to claim 1, wherein the elastic connecting portion is an elastic body that is coaxially fixed to the support shaft, and the second rotating portion is fixed to the outer peripheral portion. .. 3. The second rotating part is rotatably fitted on the support shaft, and the elastic connecting part is interposed between the first rotating part and the second rotating part. Claim 1 characterized by the above-mentioned.
The described impedance roller device.