JP2684784B2 - Tape guide drum device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape guide drum device effective for use in a magnetic recording / reproducing apparatus for recording / reproducing signals.

2. Description of the Related Art In recent years, there has been a demand for a magnetic recording / reproducing apparatus that is light in weight and cost-effective.

Along with this, similar demands have arisen for the taper guide drum device.

An example of the above-mentioned conventional taper guide drum device will be described below with reference to the drawings.

FIG. 2 shows a cross section of a conventional taper guide drum device.

The structure and operation will be described. First, the lower drum 10 for guiding the magnetic taper has a ball bearing 14 for bearing the shaft 12, a fixed transformer 18 for transmitting a signal from the magnetic head 16, and a motor for rotation. Stator 2 for
0 etc. is fixed. The winding of the fixed transformer 18 is relayed to the flexible printed board 24 via the terminal 22 and connected to a circuit (not shown) of the main body.

On the other hand, on the rotating side, a rotating drum 30 having a magnetic head 16 is fixed to an upper end surface 28 of a disk 26 fixed to the shaft 12. The shaft 12 is supported by a ball bearing 14 which is preloaded by a preload boss 32.

At the lower end of the shaft 12 is a sub-rotor made of a magnetic metal plate.
A rotor boss 36, to which 34 is caulked and fixed, is fixed by a screw 38. On the end surface of the rotor boss 36, a stator
A magnet case 42 made of a metal plate made of a magnetic material and having a shape in which a rotor magnet 40 is arranged at a position facing the sub-rotor 34 across the 20 is fixed by a screw 43.

The reason why the preload boss 32 and the rotor boss 36 cannot be used in common is that in order to strictly control the height of the magnetic head 16, after the preload is applied to the ball bearing 14 in the manufacturing process, the upper end surface 28 of the disk 26 is processed. There is a need to. At this time,
When chucking the lower drum 10 in the processing machine, it is impossible to chuck the housing portion 44 of the lower drum 10 if the rotor boss 36 also serves as the preload boss 32, and the outer peripheral portion 46 is chucked. The flexible printed circuit board 24 interferes with the work efficiency. Therefore, the preload boss 32 and the rotor boss 36 are separated from each other, and after the preload is applied by the preload boss 32, the outer peripheral portion 46 of the lower drum 10 is chucked and the upper end surface of the disk 26 is attached before the flexible printed circuit board 24 is attached.
28 is processed, and then the flexible printed board 24 and the rotor boss 36 are fixed.

However, in the above-mentioned configuration, since the preload boss 32 and the rotor boss 36 are located in the axial direction, the axial length naturally becomes long, and it is not possible to expect a reduction in thickness. Then, when the span of the rotor boss 36 is shortened, the run-out occurs, and the surface runout of the sub-rotor 34 and the rotor magnet 40 increases, which has a problem of significantly affecting the performance.

Further, since the preload boss 32, the rotor boss 36, and the two types of bosses that require precision are used, the cost is also a heavy burden.

In view of the above problems, the present invention provides a tape guide drum device having a simple structure and a reduced thickness without changing the conventional manufacturing process.

Means for Solving the Problems In order to solve the above problems, in a tape guide drum device of the present invention, a motor for driving a rotary drum equipped with a magnetic head for recording and reproducing a video signal on a magnetic tape is a flat surface. A rotor magnet in which a plurality of poles are magnetized, a magnet support means composed of a magnetic body for supporting the rotor magnet, and a magnetic body for concentrating the magnetic flux of the rotor magnet. Magnetic flux concentrating means configured to have a constant air gap facing the magnetized surface of the motor, and the stator of the motor is positioned with a predetermined gap in the air gap, the magnet supporting means and the magnetic flux concentrating means. A cylindrical spacer means mounted between the rotor magnet and the magnetized surface of the rotor magnet and the magnetic flux concentrating means to form a predetermined gap; It is composed of a pair of bearing means for bearing the drum and a preload means for applying a preload to the bearing means. A magnetic flux concentrating means is inserted into the outer circumference of the preload means, and a spacer means is further inserted, and then the magnet support is provided. The means is brought into contact with the end surface of the cylindrical spacer means, and at the same time, is fixed to the end surface of the preload means so as to secure a constant gap between the rotor magnet and the magnetic flux concentrating means.

Action The present invention can configure the motor unit without providing the magnetic flux concentrating means with a dedicated mounting member according to the above configuration.

Example A tape guide drum device according to an example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a cross section of a tape guide drum device in an embodiment of the present invention.

The structure and operation will be described. First, the lower drum 10 for guiding the magnetic tape has a ball bearing 14 for bearing the shaft 12, a fixed transformer 18 for transmitting a signal from the magnetic head 16, and a motor for rotation. Stator 2 for
0 etc. is fixed. The winding of the fixed transformer 18 is relayed to the flexible printed board 24 via the terminal 22 and connected to the rotation (not shown) of the main body.

On the other hand, on the rotating side, a rotating dome 30 having a magnetic head 16 is fixed to an upper end surface 28 of a disk 26 fixed to the shaft 12. The shaft 12 is supported by a preload boss 32 and a ball bearing 14 which is preloaded by a screw 31.

On the outer circumference of the preload boss 32, a sub-rotor 54 made of a magnetic metal plate and a spacer 50 formed of resin in a ring shape are inserted with a gap.

On the end surface of the preload boss 36, a magnet case 52 made of a magnetic metal plate is formed, in which a rotor magnet 56 is arranged at a position facing the sub-rotor 54 with the stator 20 interposed therebetween, and a height adjustment washer. It is fixed by screws 43 across 45. The rotor magnet 56 is magnetized with a plurality of poles on the surface facing the sub rotor 54, and rotates by energizing the coil of the stator 20 arranged between the rotor magnet 56 and the sub rotor 54. The sub rotor 54 is attracted by the magnetic attraction force of the rotor magnet 56, but the end surface portion 58 of the spacer 50 contacts the magnet case 52, and the gap between the rotor magnet 56 and the sub rotor 54 is kept constant.

The sub-rotor 54 may be formed integrally with the spacer 50 by drawing, but the parallelism between the end surface portion 58 and the sub-rotor 54 does not occur, and there is a risk that surface vibration will occur and the characteristics of the motor will deteriorate. is there.

Further, in order to strictly control the height of the magnetic head 16, in the manufacturing process, after the preload is applied to the ball bearing 14 by the preload boss 32, when the upper end surface 28 of the disk 26 is processed, the sub rotor 54 Since the housing part 44 or the outer peripheral part 46 of the lower drum 10 can be chucked and processed in the processing machine before the insertion, the manufacturing process is extremely advantageous.

EFFECTS OF THE INVENTION As described above, the present invention is the magnetic flux concentration vinegar stage (sub-rotor 54).
Spacer means (spacer 50) is provided between the magnet support means (magnet case 52) and the outer circumference of the preload means (preload boss 32) is used as a guide, and at the same time, the end surface portion of the spacer means contacts the magnet support means. Since the desired air gap is obtained by doing so, it is possible to realize a thin motor unit having a small number of parts.

[Brief description of the drawings]

FIG. 1 is a sectional view of a tape guide drum device according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional tape guide drum device. 32 …… preload boss, 50 …… spacer, 52 …… magnet case, 54 …… sub-rotor, 56 …… rotor magnet, 58
...... End face.

Claims (1)

(57) [Claims] 1. A motor for driving a rotary drum equipped with a magnetic head for recording / reproducing a video signal on / from a magnetic tape, wherein a rotor magnet having a plurality of poles magnetized on a plane, and the rotor magnet. A magnet supporting means made of a magnetic material for supporting, and a magnetic material for concentrating the magnetic flux of the rotor magnet, and having a certain air gap facing the magnetized surface of the rotor magnet, between the air gaps. The stator of the motor is mounted between the magnet supporting means and the magnetic flux concentrating means so that the stator has a predetermined gap, and the magnetizing surface of the rotor magnet and the magnetic flux concentrating means are installed. Cylindrical spacer means configured to form a predetermined gap, a pair of bearing means for bearing the rotary drum, and a preload on the bearing means. And a magnetic flux concentrating means is inserted into the outer circumference of the preloading means, the spacer means is further inserted, and the magnet supporting means is brought into contact with the end surface of the cylindrical spacer means. A tape guide drum device, characterized in that the tape guide drum device is fixed to an end face so as to ensure a constant gap between the rotor magnet and the magnetic flux concentration means.