JPS5960729A - Head drum of magnetic recording device - Google Patents

Abstract

PURPOSE:To attain miniaturization as well as to improve both assembling performance and mass-productivity for a head drum of a magnetic recording device by performing the assembly so that a center shaft supported fixedly and piled on the basis of a lower fixed drum and at the same time setting a driving source which drives a rotary sleeve into the head drum. CONSTITUTION:A rotary sleeve 19 is supported rotatably to a center fixed shaft 18 by means of the 1st and the 2nd bearings 20 and 21 which are set to the sleeve 19. A magnetic head 23 attached to a head fitting ring 16 protrudes to the outside slightly over the outer circumference surfaces of upper and lower fixed drums 17 and 15 and then revolved. Then the head 23 reads or records the magnetic signals to a magnetic tape traveling on the outer circumferences of drums 17 and 15. The drum 17 is attached attachably and detachably to a fixed metallic fixture 22 which is supported fixedly to the shaft 18 supported fixedly by the drum 15 by a fitting screw 29 with a minute gap secured to the drum 15.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a head drum of a video tape recorder (hereinafter referred to as VTR).

Conventional configurations and their problems The configuration of a VTR head drum has various shapes, but basically it consists of two cylindrical bodies (hereinafter referred to as: (called a drum). Conventional fixed lower drum, fixed upper L/ram type V
As shown in Fig. 1, the head drums of the TR are a fixed drum 1, a rotating hent drum 2, and a fixed upper drum 3. The lower fixed drum 1 and the upper fixed drum 3 are supported and fixed to a coupler 4 by mounting screws 6. has been done. Above fixed lower drum 1
A housing 6 is fixed to the lower surface of the housing 6.
The second bearing 9 located at the lower end of the shaft and set with the bearing adjustment nut 7 and the first bearing 8 of the fixed lower drum 1 connect the central rotating shaft 1.
A drum gooly 12 with a flywheel 11 attached thereto and a brake rotor core 13 are fixed to the part of the central rotating shaft 10 that hangs down below the housing 6, while a brake rotor core 13 is fixed upright above the fixed lower drum 1. A flange 14 to which the rotating head drum 2 is attached is fixed to the portion where the rotary head drum 2 is attached. Therefore, when the power from the drive source is transmitted to the drum pulley 12 through a belt (not shown), the central rotating shaft 14 rotates and the rotary head drum 2 also rotates. In this method, the height of the magnetic tape in the width direction is ideally controlled accurately, and the magnetic tape can run smoothly in the length direction. However, in order to seamlessly record one field of video signals at a time, recording on magnetic tape using a magnetic head has traditionally been carried out by running the magnetic tape diagonally wound around the head drum. The running of the magnetic tape against the magnetic tape is carried out using a diagonal scanning force method to increase the recording density per unit area of the magnetic tape and to increase the length of one scanning line.

However, as VTRs become smaller, the width of the magnetic tape inevitably becomes shorter, and with the conventional winding angle of the magnetic tape around the head drum, it is no longer possible to seamlessly record one field at a time. For this reason, it is necessary to increase the wrapping angle of the magnetic tape around the head drum. In the conventional head drum, there are a fixed lower drum 1 and a fixed upper drum 3.
The coupler 4, which supports and fixes the magnetic tape on the outer periphery of the drum, becomes smaller and cannot provide sufficient support, and also adversely affects the running performance of the magnetic tape. Furthermore, in recent years, there has been a demand for VTRs to be smaller and lighter, and with this, head drums have also been required to be smaller and lighter.

In the conventional head drum of the central rotating shaft type, the drive source for rotationally driving the central rotating shaft 10 is provided below the housing 6, which increases the overall length and makes the head drum smaller and lighter. It is disadvantageous to Next, the head drum based on the central rotating shaft method requires many assembly jigs to insert and attach each part above and below the fixed lower drum 1 as a reference, and at the same time, it requires cutting again during assembly. Since it is necessary to perform run-out correction, etc., there are problems with assembly and mass production.

OBJECTS OF THE INVENTION The present invention solves the problems of the conventional example, increases signal recording density on magnetic tape, and improves ease of assembly.

The aim is to improve mass productivity.

Structure of the Invention The present invention consists of a fixed lower drum, a central fixed shaft disposed coaxially with the fixed lower drum, a rotating sleeve to which a ring is attached to which the head rotates around the same axis as the central fixed shaft, and a diameter of the fixed lower drum. Almost the same as the lower fixed drum, the lower fixed drum is removably replaced by a fixed bracket fixedly supported on the central fixed shaft with a slight clearance between the lower fixed drum and the lower fixed drum to rotate the rotary sleeve. Consists of a stator unit installed on the drum and a rotor unit installed on the rotating sleeve, increasing signal recording density on magnetic tape.
It also has the effect of improving miniaturization, ease of assembly, and mass production.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the figure, 15 is a fixed lower drum, 16 is a ring for attaching the head, and 17 is a fixed upper drum, which supports and fixes the central fixed shaft 18 by press-fitting or shrink-fitting into the fixed lower drum 15. The stator unit 25 is set in a fixed position on the fixed lower drum 16 and fixed with screws 26. Next, the rotating sleeve 19 is attached to the central fixed shaft 18,
It is rotatably supported by a first bearing 20 and a second bearing 21 set in a rotating sleeve 19. In addition, the first bearing 20,
The second bearing 21 may include a ball bearing, a metal, and a static pressure or dynamic pressure fluid bearing.

Further, a rotor unit 24 is attached to the rotary sleeve 19 with screws 27 to form a motor together with a stator unit 26 attached to the fixed lower drum 15, and the rotor unit 24 is attached as a means for rotating the rotary sleeve 19. It is being A head supplementary ring 16 is fixed to this rotating sleeve 19 with screws 28, and a magnetic head 23 attached to the head ring 16 is attached to the outer periphery of the fixed upper drum 1a and the fixed lower drum 15. Magnetic signals are read or recorded on a magnetic tape that rotates while protruding slightly outward from the surface and runs on the outer peripheral surfaces of the fixed upper drum 17 and the fixed lower drum 15.

Next, the fixed upper drum 17 is attached to a fixed metal fitting 22 that is fixedly supported on a central fixed shaft 18 that is supported and fixed on the fixed lower drum 15.
Fixed to the lower drum 15 with a slight gap, a few screws 2
It can be detachably attached at 9. In addition, fixed upper drum 1
The engagement between 7 and the fixing fitting 22 includes a method of fixing with screws after positioning with splines or the like.

The head drum constructed as described above has a fixed lower drum 1 and a fixed upper drum 3 connected by a coupler 4 provided on the outer periphery of the drum, which was done in the conventional head drum with a fixed lower drum and a fixed upper drum (Fig. 1). Unlike the support fixation of
What used to be the central rotating shaft 10 in the past is replaced with a central fixed shaft 18, which supports and fixes the fixed lower drum 15 and the fixed upper drum 17, making it possible to eliminate the coupler 4 provided on the outer periphery of the drum.

Effects of the Invention As described above, according to this embodiment, the winding angle of the magnetic tape around the outer periphery of the drum can be increased only in the portion where the coupler 4 is not provided, and one frame of the magnetic signal to the magnetic tape can be increased. It is now possible to record one drum, increasing the recording density per unit area, and making use of the advantages of the conventional heno-drum.

Further, the head drum according to the present invention is assembled so as to be stacked with the central shaft fixedly supported on the basis of the fixed lower drum, and the drive source for rotating the rotary sleeve is built into the head drum, unlike the conventional head drum. Compared to a head drum, it can be made smaller and easier to assemble and mass-produced, and magnetic nodules can be replaced with higher accuracy than before when repairing or the like.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a conventional example, and FIG. 2 is a vertical cross-sectional view showing an embodiment of the present invention. 1.16...Fixed lower drum, 2...Rotating head 1' ram, 3,17...Fixed upper drum, 4...Coupler, 5.26 .27.28.2
9... several phrases are screws, 6... housing,
7... Bearing adjustment, 1., 8.20...
・First bearing, 9, 21...Second bearing, 10...
... Central rotation axis, 11 ... Eel on fly 7, 12 ... Drum pulley, 13 ... Brake rotor core, 14 ... Flange, 16 ...
...Head retainer (=J ring, 18...Center fixed shaft, 19...Rotating sleeve, 22...
...Fixing bracket, 23...Magnetic head, 24...
...Rotor unit, 25...Stator unit throat. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] A cylindrical fixed lower drum, a central fixed shaft fixedly supported by this fixed lower drum, a rotating sleeve rotatably fitted to this central fixed shaft, and a head machining allowance detachably attached to this rotating sleeve. includes a ring, a fixing bracket fixedly supported on the central fixed shaft, and a removable reprintable part having a diameter substantially the same as the fixed lower drum and having a slight gap with the fixed lower drum. a fixed upper drum; a first bearing part and a second bearing part that are interposed between the central fixed shaft and the rotating sleeve and support the rotating sleeve;
A head drum of a magnetic recording device comprising a stator unit provided on the fixed lower drum and a rotor unit provided on the rotating sleeve to rotate and drive the rotating sleeve.