JPH0278011A - Rotary drum device - Google Patents

Abstract

PURPOSE:To realize a rotary drum device at high rotational accuracy and without an unnecessary vibration by forming an L-shaped groove on one of the cylindrical surfaces constituting a coaxial type rotary transformer. CONSTITUTION:Dynamic pressure rings 13a and 13b are fixed at a rotor 4 of the coaxial type rotary transformer, and dynamic pressure ring stators 14a and 14b facing the rings 13a and 13b are fixed at a stator 10 of the rotary transformer. Further, the L-shaped groove is formed at least on one of the cylindrical surfaces of the rings. By the groove, a dynamic pressure bearing with air to generate radial force on the facing surfaces as a lubricating fluid is formed. Consequently, even when play exists between a rotary bearing and the internal ring of a ball bearing 8, the rolling of the rotary member due to the play can be suppressed, an air lubricating layer works as a damper, and the unnecessary vibration can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic recording/reproducing device having a rotating head, and particularly to an improvement of a rotary transformer in a rotating drum device.

[Prior Art] Recent magnetic recording and reproducing devices having a rotating drum device are required to have higher accuracy as the recording density increases, and a conventional rotating drum device is shown in Fig. 4. is a rotating shaft, 2 is a sleeve fixed to the rotating shaft 1, 3 is an upper drum fixed to the sleeve 2, 4 is a rotor of a coaxial rotary transformer fixed to the sleeve 2, and 5 is fixed to the upper drum 3. The head, 6 is a motor magnet housing fixed to the rotating shaft l, and 7 is a motor magnet, which are referred to as rotating members.

The ball bearing 8 is fitted onto the rotating shaft l, and its outer ring is fixed to the lower drum 9. IO is a coaxial rotary transformer stator fixed to the lower drum 9. 11 is the lower drum 9
A coil housing 12 is fixed to the motor coil, and the above is referred to as a fixed member.

In the above configuration, when the motor coil 12 is energized, the motor magnet 7 rotates, and the rotating member rotates via the rotating shaft l.

[Problems to be Solved by the Invention] In the above configuration, since the rotating shaft l is supported by the ball bearing 8, run-out rotation of the rotating member due to play between the rotating shaft l and the ball bearing 8, etc. It was difficult to suppress it sufficiently.

In order to suppress the runout rotation of the rotating member described above, the ball bearing 8
It is possible to increase the distance between the two ball bearings 8, but since the two ball bearings 8 are fitted together, it would be difficult to accurately achieve coaxiality between them, which would reduce the rotation accuracy of the rotating drum device. There was a drawback.

The present invention has been made to solve these drawbacks, and an object of the present invention is to provide a magnetic recording/reproducing device with a simple configuration and high rotation precision of a rotating drum device.

[Means for Solving the Problems] In order to achieve the above object, the present invention forms a dynamic pressure bearing that uses air, which generates radial force, as a lubricating fluid on the opposing surface of a coaxial rotary transformer. be.

[Function] By configuring as described above, the rotating shaft l and the ball bearing 8
Even if there is play with the inner ring of the rotary transformer, it is possible to suppress the whirling of the rotating shaft l, resulting in high rotational accuracy of the rotating drum device.In addition, the air lubricating layer acts as a damper to prevent the rotary transformer from rotating. It can also suppress the vibration of 4.

[Examples] Examples of the present invention will be described below with reference to the drawings. In FIG. 1, the numbers 1 to 12 are equivalent to the conventional example explained in FIG. 4, and the operation is the same, so the explanation thereof will be omitted. On the other hand, 13a and 13b are dynamic pressure ring rotors fixed to the rotor 4 of the coaxial rotary transformer;
4a and 14b are dynamic pressure ring stators fixed to the coaxial rotary transformer stator lO and located opposite to the dynamic pressure ring rotors 13a and 13b; at least one of these dynamic pressure rings has a dogleg shape as shown in FIG. grooves are formed on the circumferential surface.

Now, by energizing the motor coil 12, the rotating members rotate, and at this time, the rotation members 13a, 14a and 13b, 14b
An air lubricating layer or pressure distribution as shown in FIG. 2 is created by the dogleg-shaped groove between the two.

This pressure increases as the gap between the rotor and stator of the rotary transformer becomes narrower, and has the characteristic of keeping the gap at the same station constant. Therefore, the whirling of the rotating member due to the backlash of the ball bearing 8 is suppressed, and even if the gap between the dynamic pressure rings 13 and 14 becomes uneven, a force is exerted to uniformly correct it.

FIG. 3 shows another embodiment of the present invention, in which figure number 15 is a resin coating on the surface of the rotor 4 of a rotary transformer.

16 is a covering stator whose surface is similarly coated with resin on the surface of the rotary transformer stator IO, and at least one of the surfaces of these coverings is formed with a dogleg-shaped groove as shown in the second figure. . In this case, since the facing surface of the dynamic pressure groove can be made larger, the effect of suppressing whirling of the rotating member becomes even greater.

Further, as shown in FIG. 5, the same effect can be obtained by forming the lead-out groove of the rotary transformer wiring into a dogleg-shaped groove.

[Effects of the Invention] As explained above, in the present invention, by forming a hydrodynamic fluid bearing on the opposing surface of a coaxial rotary transformer, the vibration of the rotating member due to the fitting play between the ball bearing and the rotating shaft is reduced. This has the advantage that it is possible to provide a rotating drum device that suppresses rotation and has high rotational accuracy, and is free from unnecessary vibrations due to the damping effect of the dynamic pressure air layer.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a rotating drum device embodying the present invention, Fig. 2 is an enlarged view of the main part of Fig. 1, Fig. 3 is a diagram showing another embodiment of the invention, and Fig. 4 is a conventional FIG. 5 is a longitudinal cross-sectional view of the rotary drum device shown in FIG. 5, showing still another embodiment of the present invention. In the figure. l: Rotating shaft 3: Upper drum 4: Rotary transformer rotor 9: Lower drum 10: Rotary transformer stator I3, 14: Dynamic pressure ring agent Patent attorney 1) Haru Kitatake

Claims (1)

[Claims] A rotating drum device comprising a fixed member and a rotating member, and having a coaxial type rotary transformer for transmitting and receiving signals between the rotating member and the fixed member, wherein the rotating member is rotatable by the fixed member by a ball bearing. 1. A rotating drum device, characterized in that a dogleg-shaped groove is formed in at least one cylindrical surface of the coaxial rotary transformer.