JPH0610528Y2 - Rotating magnetic head device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Field of Application> The present invention relates to a rotary magnetic head device provided in a helical scan type video tape recorder.

<Prior Art> Conventionally, in a helical scan type video tape recorder, for example, a fixed side tape winding drum erected on a chassis and a rotation side on which a magnetic head is rotationally driven by a drive motor at high speed are mounted. A rotary magnetic head device is provided which is coaxially assembled with a tape winding drum. In this rotary magnetic head device, a magnetic tape that is obliquely wound around the outer circumference of each tape winding drum and a magnetic head that is swung by the rotation of the rotating-side tape winding drum are brought into sliding contact to record or record a video signal. It is designed to be played back.

Further, in such a rotary magnetic head device, a lead step portion for restricting the winding traveling position of the magnetic tape is spirally formed on the fixed side tape winding drum. Of the above tape winding drums, the tape winding drum on the rotating side is formed to have a larger diameter than the tape winding drum on the fixed side. Due to the step between the drums, the magnetic tape wound here is Due to the tension, a biasing force is applied from the rotating side to the fixed side, and the side edge portion thereof comes into contact with the lead step portion, so that an appropriate winding traveling position is maintained.

Further, in such a rotary magnetic head device, if the gap between the tape winding drums is too large, the magnetic tape is pulled into the gap due to the reduced pressure generated inside.
Therefore, the respective tape winding drums are assembled close to each other so that the proper winding traveling state of the magnetic tape is maintained.

<Problems to be Solved by the Invention> By the way, when the tape winding drums having different diameters are provided close to each other as described above, the fixed side tape winding of the rotating side tape winding drum having a large diameter is provided. The peripheral edge portion facing the rotating drum is formed as a step portion, and the sliding contact pressure between the wound magnetic tape and the step portion locally increases. When the video tape recorder is operated in such a state, the step causes the magnetic layer on the surface of the magnetic tape to be worn and the magnetic particles to adhere to the tape winding drum, or the step causes the magnetic tape to stick to the magnetic tape. The sliding contact causes abrasion, and metal powder is developed which adheres to the tape winding drum. When such magnetic powder or metal powder is deposited on the tape winding drum, for example, a part of the magnetic powder or metal powder is dispersed and intervenes between the magnetic tape and the magnetic head, resulting in a signal loss. is there. Further, there is a problem in that the signal recorded on the magnetic tape is magnetically affected by the action of the magnetic powder, and the quality is deteriorated during reproduction.

In view of the above-mentioned circumstances, the present invention provides a rotary magnetic head device having tape winding drums having different diameters by sliding contact between the peripheral edge of the large diameter tape winding drum and the magnetic tape. It is an object of the present invention to reduce the wear of the both, prevent the generation of magnetic powder and metal powder, and ensure good recording and reproducing conditions of the video tape recorder.

<Means for Solving Problems> In order to solve the above-mentioned problems, the rotary magnetic head device according to the present invention has a pair of tape winding drums coaxially assembled with each other and having different diameters. And a peripheral edge portion of one rotating side tape winding drum having a large diameter facing the other fixed side tape winding drum has a gradual curvature from the outer peripheral surface side toward the inner diameter direction in the cross-sectional shape including the rotation axis. Is a curved shape that increases.

<Operation> In the rotary magnetic head device according to the present invention, the magnetic tape has a cross-sectional shape including the rotation axis from the outer peripheral surface of the rotating-side tape winding drum having a large diameter, and the curvature gradually increases from the outer peripheral surface toward the inner diameter direction. The tape is wound around a pair of tape winding drums along a peripheral portion of the curved tape winding drum having a curved shape and over the fixed-side tape winding drum having a small diameter to be wound and run.

<Example> Hereinafter, a specific example of the present invention will be described in detail with reference to the drawings.

The rotary magnetic head device according to the present invention is, for example, as shown in FIG. 1, rotationally driven by a stationary tape winding drum 1 standing on a chassis of a video tape recorder, a drive motor (not shown), and the like. The rotation side tape winding drum 2 is coaxially assembled with each other.

A magnetic head 3 of the rotary magnetic head device is attached to the rotating-side tape winding drum 2 so as to protrude from a notch window portion 4 formed in the tape winding drum 2.

The magnetic tape 5 is obliquely wound around the outer periphery of each tape winding drum 1 and 2, and the magnetic head 5 is attached to the magnetic tape 5 by the rotation of the tape winding drum 2 on the rotating side. Are in sliding contact with each other to record or reproduce a video signal.

Further, the fixed side tape winding drum 1 is provided with a lead step portion 6 with which one side edge of the wound magnetic tape 5 abuts and whose running position is regulated. The lead step portion 6 is integrally formed on the outer peripheral portion of the tape winding drum 1 when the tape winding drum 1 is cut, for example, and is formed in a spiral shape corresponding to the winding state of the magnetic tape 5. .

The fixed-side tape winding drum 1 is formed to have a smaller diameter than the rotating-side tape winding drum 2, and the magnetic tape 5 wound around both the drums 1 and 2 is , 2 to receive a biasing force from the tape winding drum 2 on the large diameter side toward the tape winding drum 1 on the small diameter side due to the tension, and abut on the lead step portion 6. In this way, the magnetic tape 5 has the lead step 6
The traveling position is regulated by the so that the proper winding traveling state is maintained.

Then, in the drum device having such a configuration,
A peripheral portion of the large-diameter rotating-side tape winding drum 2 that faces the fixed-side tape winding drum 1 corresponds to the curved shape of the magnetic tape 5 that is curved based on the step between the tape winding drums 1 and 2. It is formed on the curved surface 7 having the shape. As shown in the enlarged view of FIG. 2, the curved surface 7 is continuous with the outer peripheral surface of the tape winding drum 2 on the rotating side and is curved in the inner diameter direction so as to gradually increase the curvature thereof. The cross-sectional shape is a curvature shape that draws a parabola in the axial direction of the drum device. In this way, if the peripheral edge of the lower end of the large-diameter rotating-side tape winding drum 12 is previously formed into the curved surface 7 corresponding to the curved shape of the magnetic tape 5,
The magnetic tape 5 is slidably moved while being received by the curved surface 7 at a substantially uniform pressure. Therefore, the magnetic tape 5 has very little wear and damage on the surface of its magnetic layer, and can perform good signal recording / reproduction.

In this embodiment, as shown in the enlarged view of FIG. 3, the cutout window portion 4 for protruding the magnetic head 3 provided in the tape winding drum 2 on the rotating side, the corner portion thereof also smoothly continues. The curved surface 8 is formed to prevent abrasion damage of the magnetic tape 5 in the cutout window portion 4.

[Effect of device]

As is apparent from the above description of the embodiments, the rotary magnetic head device according to the present invention has tape winding drums that are assembled coaxially with each other and have different diameters, and that has a large diameter. At the peripheral portion of the drum facing the other tape winding drum, a curvature shape corresponding to the curved shape of the magnetic tape curved based on the step between the tape winding drums is provided, and the magnetic tape is applied with a substantially uniform pressure. Since a curved surface for receiving the magnetic tape is formed, the abrasion of the peripheral portion of the large-diameter tape winding drum and the magnetic tape caused by sliding contact with each other can be reduced, and the generation of magnetic powder or metal powder can be prevented. It is possible to secure a good recording state and a reproducing state of the video signal in the recorder, and it is possible to sufficiently achieve the intended purpose.

[Brief description of drawings]

FIG. 1 is a schematic front view showing an embodiment of a rotary magnetic head device according to the present invention, FIG. 2 is an enlarged sectional view of an essential part thereof, and FIG. 3 is a notch for protruding a magnetic head in the above embodiment. It is an enlarged front view of a window part. 1, 2 ... Tape winding drum 3 ... Magnetic head 7 ... Curved surface

Claims (1)

[Scope of utility model registration request] 1. A pair of tape winding drums which are coaxially assembled with each other and have different diameters, and one rotating side tape winding drum having a large diameter and the other fixed side tape winding drum having a large diameter. A rotary magnetic head device, wherein the opposing peripheral portions have a curved shape in which the curvature gradually increases from the outer peripheral surface side toward the inner diameter direction in a cross-sectional shape including the rotation axis.