JPS5984369A - Rotary drum device of video tape recording/reproducing device - Google Patents

Abstract

PURPOSE:To make the area necessary for fitting small and miniaturize the device by surrounding a fixed drum with the annular part of a fitting member, and supporting the fixed drum by plural fitting parts extending inward provided in the annular part. CONSTITUTION:A fitting member 27 that fixes a fixed drum 4 consists of an annular part 28 that surrounds the drum 4 in radial direction, plural fitting parts 29 extending in radial direction and a bracket 3 extending outward. When a positioning pin 32 is fitted to a positioning hole provided in the stepped part of th fixed drum 4 and a screw 36 is tightened in fitting, mutual relation of the fitting member and drum 4 is maintained exactly and fixed. Then, a pin 39 is fitted to the positioning hole of a chassis, and the bracket 3 is fixed to the chassis with a screw 38. Thus, the space required for fitting becomes small, and the device can be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rotating drum device for a helical ganning type videotape recording/playback device, and more specifically, the present invention relates to a rotating drum device for a helical ganning type videotape recording/playback device. The present invention relates to a structure for attaching and fixing the invention to a fixed position.

Prior art A typical prior art is shown in FIG. 1, and its longitudinal section is shown in FIG. 2.
A cross section taken from the ill is shown in FIG.

A magnetic head 2 attached to a magnetic video tape is fixed to the rotating drum 1. This rotating drum 1 is fixed to one end of a rotating shaft 3. Three rotating shafts are rotatably supported on a fixed drum 4 by ball bearings 5 and 6.

A rotor 8 of a direct drive motor 7 is fixed to the other end of the rotating shaft 3. The electrical signal from the magnetic head 2 is
It is led out to the outside via the rotary transformer 9. A helical lead groove 10 is formed in the fixed drum 4.

A mounting member 11 is used to fix the fixed drum 4 to the chassis. This mounting member 11 is attached to the rotating drum 4.
An annular portion 14 through which the small diameter portion 12 of the is inserted and abuts the end portion 13.
and a bracket 15 fixed to the annular portion 14. Flexible holes 16 are formed in the annular portion 14 at equal intervals in the circumferential direction. The fixed drum 4 is fixed to the annular portion 14 by a screw 17 inserted through the accommodating hole 16 . A screw 18 is loosely attached to the bracket 15 and is screwed and fixed to the chassis. The bracket 15 is also provided with a positioning pin 19 that protrudes toward the chassis, and the positioning pin 19 and the positioning hole formed in the chassis fit snugly to connect the bracket 11 and the chassis. The mutual positions are determined with high precision.

In Hiko's prior art, the entire circumference of the small diameter portion 12 of the identification drum 4 is surrounded by the annular portion 14 of the mounting portion 11, so that the small diameter portion 12 of the identification drum 4 is surrounded by the annular portion 14 of the fixed drum 4.

A relatively large installation requires space between the direct drive motor 7 and the direct drive motor 7. In the future, rotary drum devices are becoming smaller in outer diameter and thinner, and the fact that such a large installation requires all the space will be a major hindrance to downsizing the rotary drum device.

OBJECT It is an object of the present invention to provide a rotating drum device for a videotape recording/playback device that is miniaturized.

FIG. 4 is an exploded perspective view of one embodiment of the present invention, FIG. 5 is a longitudinal cross-sectional view of the whole, and FIG. 6 is a cross-sectional view taken from the section line ■-vt in FIG. be. In a rotating drum device # in a helical scan type video chip recording/sharpening device, a magnetic head 2 is fixed to a rotating drum 1. This rotating drum 1 is fixed to a rotating shaft 3 via a post 21. The rotating drum 1 is rotatably supported by a fixed drum 4 provided coaxially with the rotating drum 1 by a ball bearing 5.6. A rotor 8 constituting a direct drive motor 7'f is fixed to the other end of the rotating shaft 3 via a boss 22. The rotor 8 of the motor 7 consists of a permanent magnet piece 23 and a ring 24. Permanent magnet piece 23
d: Magnetically coupled to magnetic field generating means z5 including a coil. This magnetic field generating means 25 is fixed to the fixed drum 4. The mounting member 2 is attached around the small diameter portion 26 of the fixed drum 4.
7 is placed. The fixed drum 4 is fixed to a chassis or the like by this mounting member 27.

The mounting member 27 includes an annular portion 28 that surrounds the fixed drum 4 radially outward, a plurality of mounting portions 29 (two in this embodiment) extending radially inward from the annular portion 28, and the annular portion 28. and a bracket 30 extending radially outwardly from the bracket 30 for being secured in a fixed position. A positioning pin 32 extending in the direction of the axis fM31 of the rotating shaft 3 is provided on the mounting portion 29 so as to extend in the direction of the fixed drum 4 . The mounting portions 29 and the positioning bins 32 are provided at equal intervals in the circumferential direction, and in the illustrated embodiment, a pair are provided. The annular portion 28 is also provided with a fixing portion 33 extending radially inwardly. A flexible hole 34 is formed in this fixed portion 33 . The identification portions 33 are also arranged at equal intervals in the circumferential direction, and the accommodating hole 340 axis is on one side diameter line perpendicular to the one diameter line of the annular portion 28 passing through the axis of the positioning pin 32. A positioning hole 35 is formed in the stepped surface 13 of the fixed drum 4, into which the positioning pin 32 is tightly fitted. Also, the accommodation hole 34
A tapped hole 37 is formed in the fixed drum 4 and has a female thread into which the screw 3G is loosely inserted. The upper surfaces of the attachment portion 29 and the fixing portion 33 are inclined at a helical angle θ with respect to the lower surface of the annular portion 28 . In this manner, the positioning pin 32 is tightly fitted into the positioning hole 35, thereby achieving accurate mutual positioning and fixing of the mounting member 27 and the stationary drum 4. The annular portion 28 surrounds the fixed drum 4 in the radial direction, and is attached to the mounting portion 29 and the fixed portion 3.
3 protrudes radially inward, the area indicated by reference numeral 37 in FIG. 6 can accommodate all of the printed wiring board and electronic circuit elements of the direct drive motor 7.

A screw 38 is also loosely inserted into the bracket 30.

A positioning pin 39 is formed on this bracket 30 so as to protrude in a direction opposite to the identification drum 4. A bracket 30 is fixed to the chassis by screws 38. At this time, the positioning pin 39 is tightly fitted into the positioning hole (not shown) formed in the chassis, and the mounting member 27 is
The mutual mounting positions of the main chassis and the main chassis are set accurately.

FIG. 7 is a perspective view of a portion of another embodiment of the invention, in which corresponding parts of the previous embodiment are given the same reference numerals. What should be noted is that the mounting part 40 extends to the outer periphery of the fixed drum 4 and is erected on the annular part 28. , is screwed into a screw hole 37 formed in the fixed drum 4.According to such an embodiment, since the end portion 13 only comes into contact with the mounting portion 29, the end portion and the direct drive motor 7 are in contact with each other. It is convenient that a relatively large space can be provided between the magnetic field generating means 25 and the magnetic field generating means 25.

Effects As described above, according to the present invention, the annular portion t of the mounting portion I surrounds the fixed drum, and the plurality of mounting portions extending radially inward support the fixed drum. It is possible to reduce the space required, and also to shorten the length in the axial direction, making it possible to downsize. In addition, positioning pins extending in the axial direction are installed in the mounting portion, and each of the positioning pins is individually and snugly fitted into the positioning hole formed in the fixed drum, so that the mounting member and the fixed drum are not connected to each other. Mutual positioning and fixing can be achieved accurately.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the prior art, Fig. 2 is a longitudinal sectional view of the prior art shown in Fig. t1@1, and Fig. 3 is a section line II of Fig. 2.
41 is a partially exploded perspective view of an embodiment of the present invention, FIG. 5 is a vertical sectional view of the embodiment shown in FIG. 4, and FIG. Cutting plane line Vl-Vl in Figure 5
FIG. 7 is a cross-sectional view of another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Rotating drum, 2... Magnetic head, 3... Rotating shaft, 4... Fixed drum, 5, 6... Ball bearing, 7... Direct drive motor, 27...
Mounting member, 28... Annular part, 29... Mounting part, 30
...Bracket, 32...Mounting bin, 33.40.
...Fixing part, 34, 41...Accessibility hole, 35...Mounting hole, 37...Threading Fig. 1 Fig. 3 Fig. 5

Claims (1)

[Claims] A videotape recording/playback device in which a magnetic head attached to a rotating drum is attached to a magnetic video tape, and the rotating drum is rotatably supported by a fixed drum coaxially provided with the rotating drum. A rotating drum device including: an annular portion surrounding the rotating drum; a mounting portion extending radially inward from the annular portion; and a bracket extending radially outward from the annular portion and fixed at a fixed position. A positioning pin extending in the axial direction is provided upright in each of the mounting parts of the mounting part, and positioning holes into which the positioning pins fit individually are formed in the fixed drum. What are you doing? A rotary drum device for a videotape recording/playback device with l and f characteristics.