JPS633372B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a direct drive rotary head cylinder device for use in a video tape recorder.

Conventionally, in a rotating head cylinder device incorporating an outer rotor-type circumferentially opposed brushless motor, a bearing section that supports a rotating magnetic head and a motor section that drives the rotating magnetic head are arranged in series in the axial direction. The height of the video tape recorder was extremely high, and this was one of the reasons for preventing video tape recorders from becoming thinner.
If the rotating head cylinder device is made thinner with the conventional configuration, the span of the dynamic bearing will become shorter, and as a result, the shaft will sag, wobble, etc., and the original performance will be degraded. I end up not being able to get it.

The present invention focuses on such points and provides a rotary head cylinder device that reduces the height of the bearing portion without shortening the span thereof, thereby making it possible to make the video tape recorder thinner.

Hereinafter, the present invention will be explained based on illustrated embodiments. In the drawing, a metal lower cylinder 2 whose outer periphery can be wrapped with magnetic tape (not shown) to guide travel has a flange portion 4 approximately in the center.
It is fixed to a cylindrical base 4 with a required number of screws 3. At least one terminal hole 5 is provided in the side wall of the lower cylinder 2 in the radial direction at a position where the magnetic tape is not wound. is penetrated. The terminal 6 is a terminal wire 8 with one end bent at a right angle, insulated and held by an insulating member 10, and the one end bent at a right angle is connected to the winding of a rotary transformer stator 12 fixed to the inner upper surface of the lower cylinder 2. The other end of the terminal wire 8 protrudes to the outer circumference of the lower cylinder 2, and is inserted into a predetermined position of the head connector printed board 16 disposed below. It is soldered to the terminal. A head cable 18 for transmitting and receiving recording signals or reproduction signals is connected to the terminal of the head connector printed board 16.
One end of is connected. Further, the head connector printed board 16 is fixed to a case stand 22 incorporating an electric heat source 20 for preventing dew condensation, and the case stand 22 comes into contact with the outer peripheral edge and lower surface of the lower cylinder 2, and lowers the cylinder 2. It is fixed with screws 21 from the lower part of the cylinder 2, that is, from the direction of arrow A.

Further, a metal shield case 24 is fixed to the case stand 22 with screws 23 to cover the connecting portion of the head connector printed board 16 and shield it from high frequency waves. This shield case 24
A convex holding member 26 is integrally formed on the inner surface of the head cable 18, which presses the head cable 18 in the direction of the head connector printed board 16 to eliminate wobbling of the head cable 8 and improve the reliability of the connection. is increasing. Further, the holding member 28 integrally formed on the upper part of the shield case 24 has an upper drum 5 which will be described later by sliding contact with the magnetic tape.
In order to prevent static electricity from being generated on the ground angle 4, an earth angle 30 is attached with screws 29, the tip of which is in contact with the upper end of a main shaft 36 (made of metal), which will be described later.

The structure of the fixed part has been described above, and next, the structure of the rotating part will be explained. The outer stator portions of ball bearings 32 and 34 are press-fitted into the upper and lower end openings inside the base body 4, and the main shaft 36 is press-fitted and inserted into the rotor portions thereof. As a result, the main shaft 36 is rotatably supported at two locations, upper and lower. Here, the length of the main shaft 36 is longer than the length of the base 4, and both ends thereof are connected to the base 4.
It protrudes a predetermined length above and below. Note that 33 in the figure is a cylindrical spacer for regulating the distance between the ball bearings 32 and 33 to be constant.

On the other hand, the ball bearing 3 is attached to the lower end of the main shaft 36.
A preload boss 42 is fixed with a screw 41 via a preload holder 38 and a wave washer 40 in order to apply a predetermined preload to 2 and 34. A head drive motor 4 is provided on the lower end surface of the preload boss 42.
A rotor unit 46 constituting part 4 is fixed with screws 45. Inside the rotor unit 46, there is a stator unit 48 facing in the circumferential direction.
is fixed to the base body 4 with screws 49, and together with the rotor unit 46 constitutes a head drive motor 44. Note that the details will be described later.

A metal rotating disk 50 is fixed to the upper part of the main shaft 36, and a metal upper cylinder 5 having a rotating magnetic head 52 is attached to the rotating disk 50.
4 is removably attached with screws 55. The rotating magnetic head 52 rotates at high speed in contact with the magnetic tape wound around the outer circumferences of the upper cylinder 54 and the lower cylinder 2, thereby recording or reproducing video signals. To explain the transmission and reception of a video signal using an example during playback, a video signal is transferred from a pre-recorded magnetic tape (not shown) to the rotating magnetic head 5.
The video signal reproduced by
The signal is relayed to the rotary transformer rotor printed board 60 via the lead wire 58, and then sent to the rotary transformer rotor 62. The rotary trans rotor 62 is connected to the rotary disc 50 together with the rotary trans printed board 60.
the rotating magnetic head 52;
Upper cylinder 54, rotating disk 50, main shaft 36
It has a structure that rotates in unison with the The lower surface of the rotary transformer rotor 62 rotates without contact with the rotary transformer stator 12 while keeping a predetermined gap therebetween, and transmits the video signal to the rotary transformer stator 12 . The video signal from the rotary transformer 12 is transmitted to a regenerative amplifier (not shown) via the aforementioned terminal wire 8, head connector printed board 16, and head cable 18.

Next, the structure of the head drive motor 44 will be explained in detail. The rotor unit 46 described above has a structure in which a position detection section 66 using high frequency induction and an annular multipolar magnet 68 are vertically provided on the inner wall surface of a magnetic case 64 made of iron. A shot ring 70, which is made of, for example, a band-shaped copper ring in which a plurality of window holes are bored at equal angular intervals, is fixed to perform high frequency modulation. Further, a PG magnet 72 is embedded in the outer peripheral portion of the magnet case 64 at a location maintaining a predetermined positional relationship with the rotary magnetic head 52 as a means for indicating the position of the rotary magnetic head 52.

Next, details of the stator unit 48 corresponding to the rotor unit 46 will be explained. A base 78 made of synthetic resin has a plurality of positioning pieces 74 and a plurality of elastic locking pieces 76 protruding in the same direction, and has a plurality of pairs of protrusions radially arranged on the outer periphery to insert the position detection coil 80. It is attached to the upper surface side of the holder 84 with screws 83, with the position detection iron core 82 sandwiched therebetween. A stator core 88 made of a laminated steel plate and provided with a stator winding 86 is fixed to the lower surface of the holder 84, and the wire end of the stator winding 86 is connected to a hole 89 formed in the stator core 88. Synthetic resin legs 90
Stator terminal 9 where a is press-fitted and held
It is wired to 0. The synthetic resin base 78 also includes the PG of the rotor unit 46 described above.
A PG coil unit 92 is installed at a position corresponding to the magnet 72, and a terminal wire 96 to which the winding 94 of the PG coil unit 92 is connected is connected to the main print along with the stator terminal 90 and the terminal wire 98 of the position detection coil 80. It passes through a plurality of holes drilled at predetermined positions in the board 100 and is attached to a predetermined circuit copper box by soldering. The main printed board 100 is positioned by a plurality of positioning pieces 74 that protrude upward from the base 78, and is held and fixed by the plurality of locking pieces 76. Further, a plurality of lead wires (not shown) are connected to the copper foil of the main printed board 100 and connected to a drive circuit of the head drive motor 44.
Note that since a well-known drive circuit can be used, a detailed explanation thereof will be omitted here.

Stator unit 4 configured as above
8 includes at least a part of the base body 4, a part of the ball bearing 34, and a preload holder 3 inside the stator core 88.
8. The wave washer 40 and the preload boss 42 are fixed from below to the base 4 with a required number of screws 49 so as to maintain a predetermined positional relationship with the rotor unit 46. .

As is clear from the above description, the present invention provides a base body that rotatably supports a main shaft that rotationally drives a rotating magnetic head, with the upper part of the base body being located inside the lower cylinder, and the lower part being a stator unit that constitutes a head drive motor. Place the stator unit inside the board and attach it to the board from below with screws.
In addition, the rotor unit constituting the head drive motor is similarly attached from below to the preload applying member attached to the lower end of the main shaft or near it, so the distance between the upper and lower bearings can be shortened. The vertical dimension of the entire rotary head cylinder device can be shortened without having to do so, which makes it possible to easily realize a compact and lightweight video tape recorder. It has excellent features such as being easy to attach and detach to and from, improving assembly workability.

[Brief explanation of the drawing]

The drawing is a side sectional view of one embodiment of the present invention. 2... lower cylinder, 3, 41, 45, 49,
55... Screw, 4... Base, 32, 34... Ball bearing, 36... Main shaft, 38... Preload holder, 40
... Wave washer, 42 ... Preload boss, 4
4... Head drive motor, 46... Rotor unit, 48... Stator unit, 50...
Rotating disk, 52...Rotating magnetic head, 54...
...Upper cylinder, 64...Magnetic case, 6
8...Multi-pole magnet, 88...Stator iron core.

Claims (1)

[Claims] 1 A stator section of a first ball bearing is attached to the upper end opening, a stator section of a second ball bearing is attached to the lower end opening, and a main shaft penetrates through the rotor sections of the first and second ball bearings. a lower cylinder that is inserted and attached, an upper cylinder that has a magnetic head and is attached to a main shaft portion that protrudes from the first ball bearing so as to be able to rotate therewith, and the second ball bearing. The main shaft part that protrudes from the
a preload applying member that rotates together with the base and is attached to apply a preload to the ball bearing; and a preload applying member that is attached from the bottom of the base with screws so that the second ball bearing and the preload applying member are located inside. A rotary head cylinder device comprising a stator unit for a head drive motor, and a rotor unit for a head drive motor, which is attached to the preload applying member from below with screws in the axial direction so that the stator unit is located inside the head drive motor. .