JP2589836B2 - Rotary drum device - Google Patents

Description

The present invention is used in a magnetic recording / reproducing apparatus such as a video tape recorder for recording / reproducing a signal on / from a magnetic tape by a helical scan method. More particularly, the present invention relates to a rotary drum device suitable for transmitting and receiving a video signal having a large number of channels.

[Conventional technology]

A conventional rotary drum device used for a magnetic recording / reproducing device such as a video tape recorder, for example, is fitted to an upper portion and a lower portion in a central cylindrical portion 41a of a lower drum 41 in a fixed state, as shown in FIG. 3, for example. A shaft 43 extending along the axis of the lower drum 41 is rotatably supported by the bearings 42. A substantially disk-shaped disk 44 is fitted on the upper end side of the shaft 43, and an upper drum 45 is further fixed to the disk 44. A plurality of magnetic heads 46 are mounted on the lower end surface of the upper drum 45. A rotary transformer 47 is provided in an internal space between the lower drum 41 and the upper drum 45 in order to transmit signals to and from the magnetic heads 46. This rotary transformer 47 has three cylindrical core members 48 and
It has a structure in which 49 and 50 are mounted concentrically, and by winding in an annular winding groove formed on the mutually facing surfaces, the outer core member 48 and the core member 49 in the intermediate position are wound. A plurality of signal transmission paths (hereinafter, referred to as channels) are provided in the axial direction on each of the opposing surfaces of the core member 49 and the opposing surfaces of the core member 49 at the intermediate position and the inner core member 50. The lower end of the outer core member 48 and the inner core member 50 is fixed to the lower drum 41 by the mounting plate 51, while the upper end of the core member 49 at the intermediate position is fixed to the disk 44. I have.

[Problems to be solved by the invention]

However, in the above conventional example, the outer core member 48 and the inner core member 50
In order to cope with the increase in the number of channels, the core members 48 and 50 are both attached to the lower drum 41. It is necessary to perform a double precision setting in which after mounting on the mounting plate 51 at a predetermined separation interval, and further mounting the lower drum 41 with a predetermined mounting accuracy. As described above, since it is necessary to repeat the positioning operation with high accuracy for each of them, there is a problem that the assembling operation becomes complicated.

Further, in the above, the magnetic heads 46.
It is connected to a core member 49 at an intermediate position which rotates together with 45, but at this time, it is necessary to detour the outer core member 48. For this reason, as shown in FIG. 3, for example, the lead wires of the respective magnetic heads 46 are once drawn out to the relay board 52 further attached to the upper surface of the upper drum 45, and the intermediate board core The connection with the member 49 is made. As a result, the length of the lead wire becomes longer, which causes a problem that, for example, the attenuation of a weak reproduction signal increases, and the noise resistance decreases. In addition, as in the case of simultaneous recording and reproduction of multiple channels, a plurality of magnetic heads 46 ...
When recording and playback are performed simultaneously, there is also a problem that crosstalk easily occurs in the relay board 52.

[Means for solving the problem]

In order to solve the above problem, the rotating drum device of the present invention has an upper drum attached via a disk to a shaft rotatably supported at the axial position of the lower drum in a fixed state, and the upper drum and In a rotary drum device in which a rotary transformer disposed in an internal space between the lower core and the lower drum is constituted by three concentric cylindrical core members having different diameters, an outer side of the three core members The core member is attached to the upper drum, the inner core member is attached to the disk, and the core member at the intermediate position is attached to the lower drum, and the signal routes of the outer core member and the inner core member are different from each other. And

(Operation)

According to the above configuration, the outer core member is provided on the upper drum,
Since the inner core member is attached to the disk and the intermediate core member is attached to the lower drum, these core members are individually attached to the upper drum, the disk, and the lower drum, respectively. In the operation of sequentially assembling the disk and the upper drum on the shaft attached to the shaft, each core member is also assembled with predetermined accuracy. That is, since the upper drum, the disc, and the lower drum are assembled with high accuracy in terms of structure, by assembling them with predetermined accuracy, the rotary transformer is assembled with high accuracy as a result. . As described above, even when the rotary transformer is configured by three core members, assembling with high accuracy can be performed without separately performing a positioning operation between the components, thereby improving the assembling workability.

Further, in the above configuration, the rotary transformer rotor rotating together with the magnetic head is constituted by two core members, an outer core member and an inner core member. For this reason, some magnetic heads can be directly connected to the outer core member, thereby reducing the wiring length.

Furthermore, since the signal routes of the outer core member and the inner core member are different from each other, at the time of simultaneous recording and playback, for example, while recording with a magnetic head directly connected to the outer core member, By performing the reproduction with the magnetic head connected to the inner core member via the relay board as in the related art, the recording signal and the reproduction signal can flow through different routes separated from each other. , It is possible to reduce crosstalk.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

As shown in FIG. 1, the lower drum 1 in a fixed state
It has a substantially cylindrical central cylindrical portion 1a extending in the vertical direction, and a lower cylinder surface portion 1b concentric with the central cylindrical portion 1a and located outside, and a lower end portion of the lower cylinder surface portion 1b has the central cylindrical portion 1a. Is formed as a shape connected to an intermediate position. Bearings 2 and 3 are shrink-fitted to the upper end and lower end of the axial through hole in the central cylindrical portion 1a, respectively. The vertically extending shaft 4 inserted through
The lower drum 1 is rotatably supported at the axial position.

A substantially disk-shaped disk 5 is provided on the outer periphery of the upper protruding portion of the shaft 4 from the upper bearing 2, and a substantially cylindrical member is provided on the outer periphery of the lower protruding portion of the shaft 4 from the lower bearing 3. Each of the collars 6 is fitted.
The disk 5 and the collar 6 are configured such that the inner peripheral sides of the respective axially opposed surfaces are brought into contact with the inner rings of the bearings 2 and 3, respectively, to apply a preload to the bearings 2 and 3.

A motor stator 7 located outside the collar 6 is attached to the lower end of the central cylindrical portion 1a of the lower drum 1. On the other hand, a motor rotor 9 is mounted on the inner peripheral surface of the cylindrical portion of the motor case 8 mounted on the lower surface of the collar 6.
Are positioned so as to face the motor stator 7 in the radial direction. The motor stator 7 and the motor rotor 9 constitute a direct drive motor, and this motor drives the shaft 4 and components attached to the shaft 4, that is, the upper drum 11, which will be described later, and the like. This motor portion is further covered with the shield case 10 from the outside.

On the other hand, an upper drum 11 is attached to the outer periphery of the disk 5, and the upper drum 11
It is designed to rotate congruently. This upper drum 11
Is screwed with its inner peripheral end side along the upper surface of the large-diameter upper end of the disk 5, while extending downward in a radially outward direction from the fastening portion and concentrically with the disk 5. An upper cylinder surface 11a is formed. The lower end surface of the upper cylinder surface 11a is located at a position close to the upper end of the lower drum 1 on the outer peripheral surface side of the lower cylinder surface 1b with a predetermined gap. In such a configuration, the outer peripheral surfaces of the upper cylinder surface portion 11a and the lower cylinder surface portion 1b are positioned on the same cylindrical surface as a cylinder surface around which the magnetic tape 13 to be described later is wound, so that high accuracy is achieved. Assembly is performed.

A plurality of magnetic heads 12 are mounted on the lower end surface of the upper cylinder surface portion 11a, respectively, so as to face from inside the gap on the outer peripheral surface between the upper cylinder surface portion 11a and the lower cylinder surface portion 1b. These magnetic heads 12 are, for example,
As shown in FIG. 2, the magnetic tape 13 is arranged circumferentially along a cylinder surface around which the magnetic tape 13 is wound over a range of approximately 270 degrees. In the case of the figure, an example of the configuration of a commercial MII-VTR is shown. In this case, the luminance signal and the chrominance signal are recorded by separate magnetic heads, and the recording is switched at 180 degrees. Therefore, a total of four magnetic heads serve as one set, and are composed of two magnetic heads 12-A1 and 12-A2 for recording luminance signals and two magnetic heads 12-A for recording color signals. Normal recording and playback is performed with A3 ・ 12−A4, and
Magnetic head for recording luminance signal 12-B1
12-B2, and magnetic heads 12-B3 and 12-B4 for recording color signals are provided. Further, for simultaneous recording and reproduction, a magnetic head 12-C1 and 12-C2 for recording a luminance signal and a magnetic head 12-C3 and 12-C4 for recording a chrominance signal are provided. When -A1 to 12-A4 are in the recording mode,
The recording state can be monitored by the magnetic heads 12-C1 to 12-C4 for simultaneous recording and reproduction. Further, in the case of the drawing, four rotary erasing heads 12-E1 to 12-E4 for erasing the luminance signal and the chrominance signal are further provided.

On the other hand, as shown in FIG. 1, a rotary transformer 20 is disposed in an internal space between the lower drum 1 and the upper drum 11 for transmitting signals to and from the plurality of magnetic heads 12. The rotary transformer 20 is constituted by three cylindrical transformer cores 21, 22, and 23 having different diameters arranged concentrically with the shaft 4 with a predetermined minute gap therebetween. An inner peripheral surface of an outer transformer core (hereinafter, referred to as an outer rotor core) 21 and an inner transformer core (hereinafter, referred to as an outer rotor core).
On the outer peripheral surface of the inner rotor core 23, a plurality of annular winding grooves for the primary winding are formed at predetermined intervals in the axial direction, and between the outer rotor core 21 and the inner rotor core 23. An outer peripheral surface facing the inner peripheral surface of the outer rotor core 21 and an inner rotor core 23
An annular winding groove for a secondary winding is formed at a position facing each primary winding groove on each of the inner peripheral surface facing the outer peripheral surface. By winding the primary winding groove and the secondary winding groove formed at positions facing each other in this manner, a plurality of signal transmission paths (hereinafter referred to as channels) are formed. A groove provided with a short ring (not shown) is further formed between channels adjacent in the axial direction in order to suppress crosstalk therebetween.

Next, the mounting structure of each of the cores 21, 22, and 23 and the wiring connection will be described.

First, the outer rotor core 21 has an upper drum
It is directly attached to the inner peripheral surface of the upper cylinder surface 11a in FIG. On the outer peripheral side of the upper part of the outer rotor core 21, a holder 25 for pulling out a winding terminal and guiding it to the magnetic heads 12 and a relay FPC (flexible printed circuit) 2
6 so that the electrical connection between the magnetic heads 12 and the outer rotor core 21 can be made directly. As shown in the figure, the upper cylinder surface 11
An escape groove 27 is formed at a position where the holder 25 is located on the inner peripheral surface of a.

On the other hand, the inner rotor core 23 is attached to the disk 5 by fitting its upper inner peripheral surface to the outer periphery of the disk 5. A large-diameter upper end portion of the disk 5 is provided with a winding terminal lead-out hole 28 penetrating upward. Through this hole 28, the winding terminal of the inner rotor core 23 is disposed above the upper drum 11. Upper relay board 29
Is to be led to. Also, the lead wire from the magnetic heads 12 ...
Are led to the upper relay board 29, where the magnetic heads 12 and the inner rotor core 23 can be electrically connected.

The intermediate stator core 22 is attached to the lower drum 1 in a state where its lower end is fitted to a positioning step surface 1c formed on an intermediate outer peripheral surface of the central cylindrical portion 1a of the lower drum 1. I have.

Thus, in the above, the outer rotor core 21 is attached to the upper drum 11, the intermediate stator core 22 is attached to the lower drum 1, and the inner rotor core 23 is attached to the disk 5. Since the upper drum 11, the lower drum 1, and the disk 5 are assembled with high accuracy in structure, each of the cores 21, 22,.
23 are individually attached in advance to the upper drum 11, the lower drum 1, and the disk 5, respectively, and then the disk 5,
By sequentially assembling the upper drum 11, each of the cores 21, 22, and 23 can be assembled with high accuracy.

Further, in the above, two outer rotor cores 21 and inner rotor cores 23 are provided as rotary trans rotors connected to the magnetic heads 12. Therefore,
The above-described normal recording / reproducing magnetic heads 12-A1 to 12-A4 include:
While directly connected to the outer rotor core 21 attached to the upper drum 11, the simultaneous recording / reproducing magnetic heads 12-C1 to 12-
C4 is once led to the upper relay board 29 at the upper position of the upper drum 11, and is amplified by an amplifier 30 further disposed above the disk 5 in order to further amplify a weak reproduction voltage. Is connected to the inner rotor core 23 attached to the inner rotor core 23. The reproduction signal is transmitted from the inner rotor core 23 to the intermediate stator core 22 and output to the outside.

When such wiring is performed, first, since the normal recording / reproducing magnetic heads 12-A1 to 12A4 are directly connected to the rotary transformer, the length of the lead wire can be minimized. Therefore, during normal reproduction, signal attenuation when used as a reproduction head is reduced, and noise resistance is improved. During simultaneous recording and reproduction, reproduction is performed by the simultaneous recording and reproduction magnetic heads 12-C1 to 12-C4 while recording is performed by the normal recording and reproduction magnetic heads 12-A1 to 12-A4. After being amplified by the amplifier 30 via the upper relay board 29, the inner rotor core 23
It flows along the path leading to. On the other hand, a signal (recording current) at the time of recording to the magnetic heads 12-A1 to 12-A4 for normal recording / reproduction.
Flows through a path directly to the outer rotor core 21 without passing through the upper relay board 29. As described above, since the reproduction signal and the recording signal flow through different routes from each other,
Interference (crosstalk) between both signals is reduced.

〔The invention's effect〕

As described above, the rotary drum device according to the present invention is configured such that the outer core member of the three concentric cylindrical core members having different diameters is the upper drum, the inner core member is the disk, and the core at the intermediate position. Attach the members to the lower drum,
In addition, the rotary transformer is configured such that a signal route between the outer core member and the inner core member is different.

By this, by assembling each core member in advance with a predetermined accuracy to each of the upper drum, the disc, and the lower drum which are assembled with high precision, even if three core members are used, When the assembly of the drum, the disk, and the lower drum is completed, a high-precision assembly state of the rotary transformer can be obtained without separately performing a positioning operation between the components of the rotary transformer, so that the assembly workability is improved.

In addition, some magnetic heads can be directly connected to the outer core member, thereby shortening the wiring length. At the time of simultaneous recording and playback, the outer core member and the inner core member are separately connected. It is possible to cause the recorded signal and the reproduced signal for the magnetic head to flow through different routes separated from each other, and as a result, it is possible to reduce the crosstalk.

[Brief description of the drawings]

1 and 2 show an embodiment of the present invention. FIG. 1 is a longitudinal sectional view of the rotary drum device. FIG. 2 is a schematic sectional view showing the arrangement of the magnetic head. FIG. 3 shows a conventional example and is a longitudinal sectional view of a rotary drum device. 1, a lower drum, 4 a shaft, 5 a disk, 11 an upper drum, 12 a magnetic head, 20 a rotary transformer, 21 an outer rotor core (outer core member), 22 an intermediate stator core (intermediate position core member), 23 Denotes an inner rotor core (inner core member).

Claims (1)

(57) [Claims] An upper drum is mounted via a disk on a shaft rotatably supported at an axial position of a lower drum in a fixed state, and is disposed in an internal space between the upper drum and the lower drum. In the rotary drum device, the rotary transformer is formed of three concentric cylindrical core members having different diameters, the outer core member of the three core members being an upper drum, and the inner core being an inner core. The rotating drum device is characterized in that the member is attached to the disk, and the core member at the intermediate position is attached to the lower drum, respectively, and the signal routes of the outer core member and the inner core member are different from each other.