JPH0786972B2 - Rotary head cylinder device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head cylinder device that can be used in video tape recorders and digital audio tape recorders.

2. Description of the Related Art In recent years, VTRs and DATs have been required to be small and lightweight, and rotary head cylinder devices in particular have also been required to have a highly reliable structure while being small and lightweight.

Hereinafter, an example of a conventional rotary head cylinder device will be described with reference to the drawings. FIG. 2 shows a sectional view of a conventional rotary head cylinder device. In FIG. 2, reference numeral 2 is an upper cylinder to which the magnetic head 3 is attached. The upper cylinder 2 is attached to a disc 1, the disc 1 is shrink-fitted to a shaft 8, and the shaft 8 is held by a ball 9. The ground plate contact 10 is in contact with the end surface of the shaft 8.

In the conventional rotary head cylinder device configured as described above, when static electricity is generated due to the contact between the magnetic head 3 and the tape, the ground plate contact is made from the shaft 8.
It had a structure to let static electricity escape to 10.

Problems to be Solved by the Invention However, in the above configuration, the shaft 8 is made of bearing steel (suj ₂ ) and therefore the ground plate contact 10 is worn very quickly, for example, has a life of about 200 hours. However, when a material other than the bearing steel is used as the material of the shaft 8, the reliability of the bearing becomes poor. Further, there is a problem that the electric resistance increases when the material of the earth plate contact 10 is changed.

In view of the above problems, the present invention provides a rotary head cylinder device in which an object made of a material different from that of the shaft is interposed on the end surface of the shaft on the motor side to contact the ground plate contact.

Means for Solving the Problems In order to solve the above-mentioned problems, the rotary head cylinder device of the present invention comprises a rotary body equipped with a magnetic head for recording and reproducing a video signal on a magnetic tape, and the rotary body. A rotating shaft, two upper and lower outer rings that are rotatably held via a plurality of balls in grooves provided at two upper and lower positions in the axial direction of the shaft, and the upper and lower outer rings between the upper and lower outer shafts. A spring for pressing the outer ring in the axial direction of the shaft to give a preload, a lower cylinder for holding the outer ring, and a contact plate made of a different material from the shaft on the motor side end surface of the shaft. It is provided with a structure for making contact with a contact.

Action The present invention has the above-described configuration, and the contact plate press-fitted to the end face of the motor-side shaft and the ground plate contact hardly cause fretting phenomenon, so that the life of the ground plate can be extended.

Embodiment A rotary head cylinder device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a sectional view of an embodiment of the present invention.
In FIG. 1, 2 is an upper cylinder to which a magnetic head is attached. The upper cylinder 2 is attached to the disc 1, and the disc 1 is shrink fitted to the shaft 8
Is held by the ball 9 in the groove 8a. Ball 9 is outer ring 9a
It is held at. The two outer rings 9a are pressed by the spring 12 in the axial direction of the shaft 8. A contact plate 11 is provided on the end surface of the shaft 8, and a ground plate contact 10 is in contact with this contact plate. Here, the contact plate 11 is made of JIS standard SUS420J2.

In the rotary head cylinder device configured as described above, when static electricity is generated between the magnetic head 3 and the tape, the static electricity is transmitted from the upper cylinder 2 to the shaft 8 and escapes to the earth plate contact 10 via the contact plate 11. In this embodiment, the earth plate contact 10 and the contact plate
11 has very little fretting phenomenon.

As described above, according to the present embodiment, when the shaft bearing is used, the life of the ground contact can be extended to about 2,000 hours by providing the contact plate of the different material (SUS420J2) on the end surface of the shaft.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to obtain an excellent effect that the life of the earth plate contact can be extremely extended.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a rotary head cylinder device of the present invention, and FIG. 2 is a sectional view of a conventional rotary head cylinder device. 1 ... disk, 2 ... upper cylinder, 3 ... magnetic head, 4 ... rotary transformer, 5 ... lower cylinder,
6 ... Stator, 7 ... Rotor, 8 ... Shaft, 9 ...
… Ball, 10 …… Ground plate contact, 11 …… Contact plate.

Claims (1)

[Claims] 1. A rotating body having a magnetic head for recording and reproducing a video signal on and from a magnetic tape, a shaft which rotates integrally with the rotating body, and an axially upper and lower portion 2 of the shaft.
Two upper and lower outer rings, which are rotatably held by a plurality of balls in grooves provided at various locations, and the upper and lower outer rings, which are between the upper and lower outer rings, are pressed in the axial direction of a shaft made of bearing steel and preloaded. A lower cylinder for holding the outer ring, a motor side end surface of the shaft mounted integrally with the shaft, and a contact plate made of a material different from that of the shaft. A rotary head cylinder device characterized by being brought into contact with each other.