JPH0316112Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a tape drive. In particular, the present invention relates to a tape drive device configured to use the driving force of a capstan direct drive motor for other drives.

[Prior art]

Conventionally, video tape recorders have used a method in which the capstan direct drive motor is driven in pulses to feed the tape at a constant pitch during low-speed playback modes, such as forward and reverse visual search modes and frame-by-frame feed modes. is taken. The rotation of the capstan motor is driven by an elastic belt, for example, to drive a reel system, but when comparing the rotation loss torque of the capstan motor itself and the load torque of the reel system to the capstan motor, the capstan motor itself is Generally small.
Therefore, when the reel system is rotated by the capstan motor, one side of the elastic belt becomes slack,
The other side is on the beam side, so when the low-speed intermittent feed capstan motor rotates at a certain angle and stops, the tension that causes the capstan motor to rotate in the opposite direction is absorbed by the beam side of the elastic belt. It was accepted and was slightly reversed. As a result, the position of the tape relative to the magnetic head deviates from its normal position by the amount that the capstan motor is rotated in the opposite direction, causing noise on the screen and degrading the image quality in the low-speed playback mode.

In order to prevent the capstan shaft from returning when the capstan motor is fed at low speed, either a special hard felt 24 is applied as a brake member to the rotor 12 of the capstan motor as shown in FIG. A method is used in which the brake is actuated by pressing the brake pad 26 against the rotor 12 via the self-holding solenoid 25, as shown in FIG.

However, in the brake mechanism shown in FIG. 5, since the reception brake acts on the rotor of the capstan motor, there is wasteful current consumption in other modes. Also, since the capstan motor rotates at high speed during rapid feed, there is a problem with the reliability of the felt.

Also, regarding the brake mechanism shown in Fig. 6, the brake can be operated in the required mode, so
Although the current consumption and the reliability of the felt are improved, there is a drawback that the cost increases due to the parts and assembly of the solenoid dedicated to this brake mechanism.

[Purpose of invention]

The present invention, in contrast to the conventional example described above, makes it possible to apply a brake to the capstan shaft without the need to keep the brake member in constant contact with the rotor and without using a dedicated solenoid. The purpose is to

[Structure of the idea]

The present invention provides a tape drive device in which the rotational force of a capstan motor that rotationally drives a capstan shaft is connected to a reel stand driving means via a belt, and the reel stand is rotationally driven by the driving force of the motor. , an electromagnetic brake means is provided for applying a brake to the rotation of the reel stand, and when the electromagnetic brake means is energized, a movable member that presses against the rotating body that rotates the reel stand integrally is moved by a certain amount in the rotational direction of the rotating body. The movable member is rotatable, and a brake member is engaged with the rotor of the capstan motor so as to be able to come into contact with the rotor of the capstan motor.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments. 1st
In the tape drive device used in the video tape recorder shown in the figure, a capstan shaft 10, a pulley 11, and a rotor 12 of a capstan motor for rotating the capstan shaft 10 and pulley 11 are integrally fixed to the underside of a chassis 1. A capstan direct drive motor is fixed thereto, and a pinch roller (not shown) is provided in pressure contact with the capstan shaft 10. On one side of the upper side of the chassis 1, there is a take-up reel stand 2 with a built-in electromagnetic brake means whose detailed configuration is shown in FIGS. 2 and 3, and on the other side, the electromagnetic brake means shown in FIG. A supply reel stand 13 with a built-in brake means is attached to each, and a take-up reel stand 2 and a supply reel stand 13 are respectively attached.
A reel stand driving rotating body 14 and an idler 15, which serve as reel stand driving means, are arranged between them. This reel stand driving means is provided with a known friction mechanism for moving the idler 15 to the reel stand 2 side and the reel stand 13 side. Rotating body 1
A belt 16 is suspended between the pulley 11 and the idler 15, and the idler 15 is selectively brought into contact with the outer periphery of the take-up reel stand 2 and the supply reel stand 13, respectively, so that the rotation of the capstan motor is transmitted to the reel stand. Ru.

A brake member 3 is provided on the lower side of the take-up reel stand 2, and a friction material 17 fixed to the tip of the brake member 3 is configured to come into contact with the rotor 12.

As shown in FIGS. 2 and 3, the electromagnetic brake means built into the take-up reel stand 2 has a fixed iron core 4a formed at the center of a fixed magnetic plate 4, and an insulating plate 5 and an excitation coil 18 surrounding it. The guide collar 6 constituting the movable member is fitted and covered with a case 7, and the case 7 is caulked and fixed to the stationary side magnetic plate 4, and the excitation coil 18 and the guide collar 6 are prevented from coming off upward by the case 7. . An annular friction material 19 such as felt is adhered and fixed to the upper surface of the case 7, and a rotating body 8 made of synthetic resin that rotates integrally with the reel stand is mounted on the upper surface of the annular friction material 19 such as felt. A movable side magnetic plate 9 constituting a movable member in which a pressure contact portion is integrally formed and a pressure contact portion is attached and fixed thereon. This movable side magnetic plate 9 is urged upwardly away by a coil spring 21, and a movable iron core portion 9a is formed at the center of the movable side magnetic plate 9, the lower end of which faces the fixed iron core portion 4a, and the movable side magnetic plate 9 The reel shaft 22 is fixed to the chassis 1 by being prevented from coming off by the guide collar 6, and the whole is made into a unit.
is inserted into.

The fixed side magnetic plate 4 is fixed to the chassis 1 with screws 23, and the reel stands 2 and 13 are attached to the reel shaft 22.
are fitted, and the reel stand 2 and the rotating body 8 are connected to each other.
The protrusions are engaged with the recesses of the reel stand 2 and are connected to rotate together. The rotor 12 of the capstan motor is attached to the reel shaft 22 on the lower side of the chassis 1.
The brake member 3 for applying a brake is rotatably fitted, and the lower end of the guide collar 6 on the reel stand 2 side and the brake member 3 are connected to the projection piece 6g.
and are engaged with each other through hole 3b.

Describing the shape of each of the above parts in detail, the brake member 3 has a hole 3a into which the reel shaft 22 is fitted and another hole 3b, and a return spring 3 to the old position.
c is integrally formed, and the tip of the spring 3c is locked to a spring locking portion 1a of the chassis 1.

The fixed side magnetic plate 4 has a fixed portion 4b protruding from its periphery, and a cutout portion 4c and a cutout portion 4d. Further, near the fixed iron core portion 4a, a protruding piece 6g of the guide collar 6 is fitted, and a hole 4e for allowing movement of the protruding piece 6g is provided in the chassis 1 at this hole position. Holes 1b are formed respectively.

A protrusion 5a is formed on the outer periphery of the insulating plate 5, and a notch 5b is formed in the protrusion 5a, into which the lead wire of the excitation coil 18 is inserted.

The guide collar 6 has a cylindrical portion 6a, a protruding plate 6b around the upper side, a lower protrusion 6c and a higher protrusion 6d upward on the protruding portion 6b, and a U-shaped protruding portion having a claw portion 6e at the upper end. 6f and a protrusion piece 6g that is fitted into the hole 4e and the hole 3b are integrally formed at the lower end of the cylindrical portion 6a.

The case 7 is formed into a cylindrical shape with a bottom, and has a protrusion 7a on the opening side that is fitted into the notch 4c of the stationary side magnetic plate 4 and fixed by caulking, and a notch into which the protrusion 5a of the insulating plate 5 is fitted. A portion 7b is formed, and a through hole 7d is formed at the center of the bottomed portion 7c, and a notch 7e is formed around the through hole 7d into which the protrusion 6c of the guide collar 6 is fitted with a gap.
A notch 7f is formed in which the protrusion 6d and the U-shaped protrusion 6f are fitted with a gap.

A protrusion 8a protrudes around the rotating body 8 and is connected to the reel stand 2, and the upper and lower surfaces of the rotating body 8 are formed with finely uneven surfaces that come into contact with the friction materials 19 and 20. ing.

A through hole 9b is bored on the outside of the movable iron core part 9a in the movable side magnetic plate 9, and after the protruding part 6f of the guide collar 6 is inserted, the claw part 6e prevents the guide collar from coming off and rotating. 6 constitutes a movable member.

The fixed iron core portion 4a of the fixed side magnetic plate 4 and the movable iron core portion 9a of the movable side magnetic plate 9 are each formed by a crimp process.

The reel stand 2 is formed into a cylindrical shape with a bottom, and has cylindrical portions 2a and 2b formed above and below the center, and an outer cylindrical portion 2c.
A notch 2d into which the protrusion 8a of the rotating body 8 is fitted is formed inside.

The electromagnetic brake means of the supply reel stand 13 is compared with the electromagnetic brake means of the take-up reel stand 2.
The only difference is that there is no protrusion piece 6g at the lower end of the guide collar 6, and the protrusions 6c and 6d are fitted with the notches 7e and 7f without any gaps; the other configurations are the same, so the details are as follows. Explanation will be omitted.

Furthermore, the brake member 3 having the friction material 17 moves in the escape direction with respect to the rotor 12 when the rotor 12 is rotated clockwise in FIG.
Furthermore, the friction material 17 is disposed so as to sink into the rotor 12 when the rotor 12 is rotated counterclockwise.

The operation of the tape drive device configured as described above will be explained below.

In the tape retreading state, the capstan motor rotates at a constant speed clockwise in FIG. 1, thereby rotating the capstan shaft 10 and feeding the tape at a constant speed. The rotational force of the capstan motor is transmitted to the rotating body 1 via a pulley 11 and a belt 16.
4 in the clockwise direction, the idler 15 moves to the right due to the rotational force of the rotating body 14 and comes into pressure contact with the reel stand 2 and the pulley of the rotating body 14.
Rotate clockwise to wind up the tape. At this time, the coil 18 of the electromagnetic brake means built in the supply reel stand 13 is energized, attracts the movable side magnetic plate 9, and presses the friction material 20 against the rotating body 8, thereby causing the reel stand 13 to brake. Force is applied and back tension is applied to the tape. In addition, in fast forward mode, a weak brake torque is applied to the reel stand 1 to give weak tension to the tape.
In the rewind mode, a weak brake torque is generated only on the electromagnetic brake means side of the reel stand 2 to apply a weak tension only to the electromagnetic brake means side of the reel stand 2 against counterclockwise rotation of the reel stand 2. It's getting old.

Furthermore, when changing from each mode to the stop state, a strong brake torque is applied to the reel stand that is the tape supply side, and a medium brake torque is applied to the reel stand that is the take-up side, so that the tape does not slacken. Each coil of the electromagnetic brake means is energized.

Next, a case will be described in which the tape is intermittently fed from the supply reel stand 13 side to the take-up reel stand 2 in a low-speed playback mode such as slow playback in a video tape recorder. In this case, the coil 18 of the take-up reel stand 2 is energized. When the coil 18 is energized, the fixed core part 4a is excited and the movable core part 9a
is attracted against the spring 21, and as the movable side magnetic plate 9 descends, the annular friction member 20 presses the rotating body 8 against the lower annular friction member 19, thereby attempting to brake the rotation of the reel stand 2.

However, in the take-up reel stand 2 shown in FIGS. 2 and 3, gaps are provided between the protrusions 6c, 6f of the guide collar 6 that holds the movable magnetic plate 9 and the notches 7e, 7d. , the reel stand 2, that is, the rotating body 8, conversely rotates the movable side magnetic plate 9 along with the rotating body 8 by the gap thereof, and therefore the guide collar 6
That is, the protruding piece 6g is moved by the rotating body 8 in the rotational direction of the reel stand 2 within the range of the gap.

Therefore, the brake member 3 rotatably held on the reel shaft 22 in FIG.
7 contacts the rotor 12 of the capstan motor. However, in this case, since the rotation direction of the intermittent rotating capstan motor, that is, the rotor 12, is clockwise, the rotation of the rotor 12 with respect to the friction material 17 is in the escape direction, and no large braking force is applied. Next, when the capstan motor is stopped due to the low-speed regeneration mode, the brake is applied, and the rotor 12 of the capstan motor receives tension that returns the tension side of the belt 16 due to the slack and tension generated in the belt 16. Therefore, the friction material 17 which was in contact with the rotor 12 receives a force in the biting direction from the rotor 12 and comes into pressure contact with the rotor 12. A braking force is applied to rotation in the reverse direction, noise on the screen caused by misalignment of the tape relative to the head is eliminated, and image quality in low-speed playback mode is improved.

Furthermore, the configuration is simplified and costs can be reduced as there is no need for a brake drive source such as a solenoid, and the functionality of the electromagnetic brake means can be increased.At the same time, the brake is applied not only to the reel stand but also to the rotor during high-speed feed and stop, which is not possible in the past. Combined with the reverse voltage applied to the capstan motor and the brake function by the circuit shot, the rotor can be stopped in a short time.

FIG. 4 shows a modification of the brake member 3, in which the tip of the brake member 3 is formed into a bifurcated shape, and friction materials 17, 17 fixed to the tip are exposed to the rotor 12 so as to be able to come into contact with the rotor 12.

By configuring the brake member 3 in this manner, it is possible to brake the clockwise and counterclockwise rotations of the rotor 12.

In the explanation of FIGS. 2 and 3 above, the fixed iron core 4a
Although it is provided integrally with the fixed side magnetic plate 4, it may be provided separately and the fixed side magnetic plate 4 may also be used by the chassis 1.

Furthermore, the guide collar 6 does not need to hold the excitation coil 18, but is moved by the movable magnetic plate 9,
It is sufficient that the brake member 3 is moved.

[Effect of idea]

Since the present invention is constructed as described above, when the excitation coil of the electromagnetic brake means that applies a brake to the rotation of the reel stand is energized and braked, the movable member that is in pressure contact with the rotating body that rotates integrally with the reel stand is rotated. The brake member is rotated a certain amount in the direction of rotation of the body, and the movable member brings the brake member into contact with the rotor of the capstan motor, and the friction material of the brake member is rotated in the opposite direction due to the tension that returns the tension side of the belt. Since the tape drive applies braking force by biting into the tape drive, it has a simple configuration and has excellent practical effects, such as eliminating noise on the screen caused by misalignment of the tape relative to the head and significantly improving image quality in low-speed playback mode. equipment can be provided.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and Fig. 1 is a plan view showing the arrangement of a tape drive device of a video tape recorder, and Fig. 2 is a cross-sectional side view of the main part inside the take-up reel stand. , FIG. 3 is an exploded perspective view of the same essential parts, and FIG. 4 is a plan view of the essential parts of a modified example of the brake member.
5 and 6 are plan views of a brake mechanism incorporated in a conventional tape drive device. 2... Reel stand, 3... Brake member, 4,
7, 18... Electromagnetic brake means, 6, 9... Movable member, 8... Rotating body, 10... Capstan shaft,
12... Rotor, 14, 15... Rotating body for driving the reel stand, 16... Belt.

Claims (1)

[Scope of utility model registration request] In a tape drive device, the rotational force of a capstan motor that rotationally drives a capstan shaft is connected to a reel stand driving means via a belt, and the reel stand is rotationally driven by the driving force of the motor, the reel stand as described above. An electromagnetic brake means is provided to apply a braking force to the rotation of the reel, and by energizing the electromagnetic brake means, a movable member that is in pressure contact with a rotating body that rotates integrally with the reel stand can be rotated by a certain amount in the rotational direction of the rotating body. A tape drive device, characterized in that a brake member is engaged with the movable member so as to be able to come into contact with the rotor of the capstan motor.