JPS6128254Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive device for a rotating magnetic head used in a video tape recorder or the like.

In this type of conventional device, the drive shaft of the rotating magnetic head is driven by a belt, which has the disadvantage that it not only causes malfunctions caused by the belt such as belt slippage, but also increases the size of the device. Therefore, it is possible to connect the drive shaft of the rotating magnetic head directly to the motor shaft, but since the rotational position of the rotating magnetic head must be strictly regulated, the drive shaft should be fitted with a pair of bearings spaced as far apart as possible to prevent eccentricity. Since the drive shaft is long, if the motor shaft is directly connected to the drive shaft, the device will become larger.

The present invention has been devised in view of these points, and one embodiment of the present invention will be described below with reference to the drawings.
Reference numeral 1 denotes a guide cylinder that guides the magnetic tape on its outer periphery, and is composed of an upper guide cylinder 2 and a lower guide cylinder 3. In the embodiment, the upper guide cylinder 2 opposes the lower guide cylinder 3 by a connector (not shown), leaving a gap. It will be fixed like this.
The lower guide cylinder 3 has a small diameter sleeve 4 protruding from its lower part, and an annular permanent magnet 5 on the outer peripheral surface of the sleeve.
A pair of bearings 7 and 8 are attached to the upper and lower ends of the sleeve inner hole 6. In this case, the mounting surfaces of the bearings 7 and 8 in the sleeve inner hole 6 are formed with high precision so that the axes of the pair of bearings coincide and are perpendicular. Reference numeral 9 denotes a drive shaft supported by the bearings 7 and 8. Between the pair of bearings 7 and 8 is a large-diameter portion 9' that comes into contact with the inner ring of the bearing, which allows the drive shaft 9 to move in the thrust direction. is prevented. A support plate 10 is fixed to the upper end of the drive shaft 9 with a nut 11 so as to be sandwiched between the nut 11 and the inner ring of the bearing 7, and the support plate 10 is fixed so as to be exactly orthogonal to the drive shaft 9. Rotating magnetic heads 11, 11, which protrude slightly outward from the gap between the upper and lower guide cylinders 2, 3 and scan the magnetic tape surface for recording and playback, are attached to the peripheral edge of the support plate 10 via support plates 12, 12. It will be done. Furthermore, rotor parts 13, 13 constituting a rotary transformer are attached to the lower part of the support plate 10 for transmitting and receiving signals from the rotary magnetic heads 11, 11, and inside the lower guide cylinder 3, a stator part 14 of the rotary transformer, 14 is attached via a mounting base 15.

Next, a mounting plate 16 is attached to the lower end of the drive shaft 9 with screws 17.
It is fixed at. The cutter rotor 18 is installed on the mounting plate.
is removably attached. The cut rotor includes a coil body 19 wound into a cylindrical shape and a retaining plate 20 for the coil body 19.
The holding plate is attached to the mounting plate 16 with screws 21 so that the coil body 19 opposes the periphery of the permanent magnet 5 with a gap therebetween. 22 is a screw 2 attached to the stepped portion 3 of the lower guide cylinder 3.
The yoke cylinder is fixed with a bracket 24, and its lower opening is removably covered with a bracket 24. The brush 25 provided on the inner surface of the bracket 24 is the commutator 2
6 and supplies power to the coil body 19.

As described above, according to the configuration of the present invention, in order to vertically support the drive shaft of the rotating magnetic head without eccentricity, consideration is given to the fact that the small-diameter sleeve of the guide cylinder, in which the pair of bearings are mounted spaced apart, becomes long. do,
An annular stator is attached to the outer peripheral surface of the sleeve, a mounting plate is fixed to the lower end of the drive shaft protruding from the sleeve, and a cylindrical rotor is mounted opposite the outer peripheral surface of the permanent magnet through a gap. Since it is removably attached to the mounting plate, the rotating shaft of the rotor can be omitted, and the outer periphery of the sleeve can be skillfully used to form the drive motor section of the drive shaft. The drive device can be downsized. Furthermore, since the cutout rotor is detachably attached to the mounting plate, the cutout rotor can be removed regardless of the drive shaft and rotating magnetic head, etc., making maintenance and inspection easy. This has great practical effects, such as avoiding the influence of magnetic lines of force on the recording and reproducing of the magnetic recording medium wound around the guide cylinder and the adverse influence on malfunction of the servo circuit provided in the device.

[Brief explanation of the drawing]

The drawing is a cross-sectional side view showing an embodiment of the device according to the present invention. 1...Guide cylinder, 5...Permanent magnet, 4...
...Small diameter sleeve, 11, 11... Rotating magnetic head, 7, 8... Bearing, 9... Drive shaft, 16... Mounting plate, 19... Coil body, 20... Holding plate, 18
...Katsuprota.

Claims (1)

[Claims for Utility Model Registration] A small-diameter sleeve that protrudes from the lower part of the guide cylinder and has an annular permanent magnet attached to its outer circumferential surface, and a rotating magnetic head that is attached to the upper end and is supported by a pair of spaced apart bearings within the sleeve. The drive shaft is formed into a cylindrical shape with a bottom, a mounting plate fixed to the lower end of the drive shaft protruding from the sleeve, a coil body wound in a cylindrical shape, and a holding plate thereof, and the holding plate is connected to the mounting plate. 1. A drive device for a rotating magnetic head, comprising a cut rotor which is detachably attached to a plate and in which the coil body opposes the permanent magnet through a gap. 2. The drive device for a rotating magnetic head according to claim 1, wherein the drive shaft has a large diameter portion between the pair of bearings that prevents movement of the drive shaft in the thrust direction.