JPS5814445Y2 - tape winding device - Google Patents

Description

[Detailed description of the invention] The present invention is a tape winding device for a recording/reproducing device such as a VTR or tape recorder, and is configured so that a winding reel base is rotationally driven by a motor via a friction clutch. It is related to.

As is well known, in recording and reproducing apparatuses, it is necessary to maintain a constant tape tension on the winding side because the tape must be wound to a constant stiffness.

Therefore, in conventional VTRs, etc., while the take-up reel stand is always driven to rotate with a constant driving torque, the brake torque of the brake attached to the take-up reel stand is adjusted to attenuate and adjust the drive torque. I was trying to adjust the tension.

However, with this brake torque adjustment method,
It is necessary to apply a very large brake torque at the beginning of winding the tape, which causes severe friction on the brake shoes and other components, resulting in a lack of durability.

Furthermore, it is difficult to correct changes in tape tension due to changes in tape winding diameter, and it is difficult to obtain a stable (flat) tape tension from the beginning of winding to the end of winding.

Furthermore, since the friction clutch is forcibly slipped by applying a brake torque to the take-up reel table, the friction clutch tends to be prone to early friction and has low durability.

In addition, as a method that can correct the above defects, Japanese Patent Application Laid-Open No. 47-2
Publication No. 1111 has already been published.

The technology disclosed in this publication consists of a take-up reel stand, a pulley that is in contact with the lower part of the take-up reel stand via a felt (friction plate), and a tension lever that is provided with a tension detection pin at one end. The cylindrical portion at the other end and the bearing are arranged on the same axis, and an inclined surface is formed on the lower surface of the cylindrical portion of the tension lever and the upper surface of the bearing, and these inclined surfaces are brought into contact with each other. A leaf spring having radial arms is interposed between the lower surface of the pulley and the upper surface of the cylindrical portion of the tension lever, and the leaf spring presses the pulley upward to press it against the felt, and at the same time, the cylindrical portion of the tension lever is pressed against the felt. The inclined cam surfaces are pressed together by pressing downward, and while the pulley is rotationally driven by the drive source, the tension lever is controlled to rotate in conjunction with the tape tension detection operation by the tension detection pin. The cylindrical part of the tension lever is moved up and down by the guiding action of
The vertical movement of the cylindrical part controls the pressing force of the pulley by the leaf spring, and the friction torque between the pulley and the take-up reel table, which is rotationally driven by the pulley, is controlled to keep the tape tension on the take-up side constant. It was designed to be.

However, in this case, since the structure is such that the leaf spring that presses the pulley against the felt directly presses circle 1 of the tension lever downward, when the pulley rotates, the leaf spring follows the pulley and rotates, causing the leaf spring to A large frictional resistance is generated between the cylinder and the cylinder due to sliding friction.

Further, the cylindrical portion and the bearing are pressed together by the inclined surfaces in a state of surface contact with each other, and sliding friction also occurs between these inclined surfaces.

Therefore, the rotation of the tension lever is heavy, and the tape tension detection sensitivity is low (as a result, it is not possible to sensitively detect minute fluctuations in tape tension and accurately control friction torque.

In addition, the pulley that is rotationally driven by the drive source is constantly subjected to large frictional resistance as described above, and this frictional resistance is caused by the vertical movement and rotational fluctuation (rotational speed) of the circular section of the tension lever (rotational speed and changes in the direction of rotation).

Therefore, the pulley has defects in that uneven rotation tends to occur and friction torque tends to fluctuate.

The present invention attempts to provide a device that can correct the above-mentioned deficiencies.

An embodiment in which the present invention is applied to a tape winding device for a VTR will be described below with reference to the drawings.

First, a reel shaft 2 is installed vertically in a chassis 1.

A sleeve 3 is rotatably fitted onto the reel shaft 2, and a take-up reel stand 4 is press-fitted into the sleeve 3 and rotatably supported.

Note that a take-up reel 5 is engaged with the upper end of the take-up reel stand 4, and the take-up reel 5 is rotationally driven by the take-up reel stand 4, and a magnetic tape (hereinafter simply referred to as tape) 6 is wound up. It is configured as follows.

A friction clutch 8 and a friction torque control mechanism 9 for the friction clutch 8 are provided below the take-up reel stand 4 on the reel shaft 2.

A tape tension detection mechanism 10 for the tape 6 wound on the take-up reel 5 is also provided.

First, the friction clutch 8 and the friction torque control mechanism 9 will be explained. In this embodiment, the friction clutch 8 and the friction torque control mechanism 9 are combined with each other.

First, a friction plate 12 made of felt or the like, a control rotating body 13, and a constant speed rotating body 14 are arranged coaxially with the reel shaft 2 at the lower part of the take-up reel stand 4.

The friction plate 12 is fixed, for example, to the lower surface of the reel stand 4 by adhesive or the like.

Further, the constant speed rotating body 14 is attached to the outer periphery of the sleeve 3, and is configured to be rotatable around its axis and slidable in its axial direction (vertical direction).

The control rotary body 13 is attached to the outer periphery of the boss portion 14a of the constant speed rotary body 14, and is configured to be relatively rotatable around its axis and slidable in the axial direction (up and down direction). has been done.

Therefore, inclined cams 16 are formed on the lower surface of the control rotary body 13 at, for example, three locations in the circumferential direction, and inclined cams 16 are formed on the upper surface of the constant speed rotary body 14 at, for example, three locations in the circumferential direction. An inclined cam surface 1T corresponding to the cam surface 16 is formed.

Incidentally, these inclined cam surfaces 16 and 17 are constituted by concave grooves that are approximately in the shape of a teardrop, as clearly shown in FIG.
They are substantially parallel to each other and are inclined at a predetermined angle with respect to the axis of the reel shaft 2.

Three spheres 18 are interposed between these mutually opposing inclined cam surfaces 16 and 170, respectively.

Furthermore, three notches 19 are formed in the constant speed rotating body 14 between the inclined cam surfaces 17.

Three pins 20 protruding from the lower surface of the control rotary body 13 are inserted into the notches 19, and one ends of the three tension springs 21 inserted into the notches 19 are connected to the pins. 20, and the other ends are respectively locked to spring locking portions 22 of the constant speed rotating body 14.

Therefore, due to the spring force of the tension spring 21, the control rotary body 13 is moved clockwise in FIG.
is rotated counterclockwise in FIG.

Note that these rotational bias directions are indicated by arrows a in Fig. 5A.
and corresponds to the b direction.

The control rotary body 13 is pressed and biased in the direction of arrow C (upward) in FIG. 5A by the component force due to the cam action between each sphere 18 and the inclined cam surface 16, 17 due to these rotational biases. is configured to be

Note that the FW is rotated at a constant speed by a motor (not shown).
A D idler 24 is pressed against the circumferential surface 14b of the constant speed rotating body 140, and is configured to rotate the constant speed rotating body 14 at a constant speed.

Further, a thrust bearing 2 is provided at the upper end of the reel shaft 2.
5 is attached to restrict the upward movement of the take-up reel stand 4.

Further, a thrust bearing 26 is provided at the lower part of the constant speed rotating body 14 so as to be slidable in the axial direction (vertical direction) with respect to the sleeve 3.

A variable torque lever 28 and a guide 29 are arranged below the thrust bearing 26.

The variable torque lever 28 is attached to the outer periphery of the reel shaft 2, and is configured to be rotatable around the axis and slidable in the axial direction (vertical direction).

The inclined cam surface 16 is located between the lower surface of the disk portion 28a of the variable torque lever 28 and the upper surface of the guide 29.
．． Inclined cam surfaces 30 and 31 similar to No. 17 are formed at, for example, three locations in the circumferential direction, and are opposed to each other.
, 310, three spheres 32 are interposed between them.

Note that the guide 29 is a threaded portion 3 formed on the reel shaft 2.
3, and is held down by a torque adjustment ring 34, which is also screwed onto the threaded portion 33, via a non-slip washer 35 at the bottom thereof.

Next, the tape tension detection mechanism 10 will be explained.

First, a tension detection lever 38 is rotatably supported on the chassis 1 via a fulcrum shaft 37.

For example, two tension detection pins 39 are installed on one end 38a of this tension detection lever 38, and these tension detection pins 39 are brought into contact with the tape 6 on the winding side as shown in FIGS. 2 and 3. There is.

An interlocking pin 41 implanted on the tip 28b of the variable torque lever 28 is engaged with a long hole 40 formed at the other end of the tension detection lever 38.

Note that the tension detection lever 38 is connected to this and the chassis 1.
The rack is biased to rotate clockwise in FIG. 3 by a tension spring 42 which is passed between the frame and the predetermined position.

The tension detection pin 39 is brought into contact with the tape 6 on the winding side as shown in FIG. 3 by the spring force of the tension spring 42.

The amount of clockwise rotation of the tension detection lever 38 is regulated by a stopper 43 installed on the chassis 1.

Next, the operation of the tape winding device constructed as above will be explained.

First, in this device, a constant speed rotating body 14 is rotated on a thrust bearing 26 supported by a variable torque lever 28.

The rotational torque of this constant speed rotating body 14 is determined by the inclined cam surface I.
T, sphere 18, control rotary body 13 via inclined cam surface 16
The control rotary body 13 rotates together with the constant speed rotary body 14.

However, during this rotation, the control rotary body 13 is urged to rotate in the direction of arrow a in FIG. 5A with respect to the constant speed rotary body 14 by the spring force of the tension spring 21.

As a result, due to the cam action of the inclined cam surfaces 16 and 17, the control rotary body 13 moves in the direction of arrow C (upward side) in FIG. 5A.
The friction plate 12 is pressed and energized by the friction plate 12.

Therefore, the rotational torque of the control rotary body 13 is transmitted to the take-up reel stand 4 via the friction plate 12, and drives the take-up reel stand 4 to rotate in the same direction.

Therefore, the pressing force of the control rotating body 13 against the friction plate 12 determines the friction torque between them, and the winding torque of the tape 6 is determined by this friction torque.

Therefore, it is the spring force of the tension spring 21 that provides the above-mentioned crimping force, and the above-mentioned crimping force is varied by changing the length t (see Fig. 4) of the tension spring 21.
is varied depending on the height of the constant speed rotating body 14.

That is, the height of the constant speed rotating body 14 changes from the state shown in FIG. 5A to the state shown in FIG. 5B.
When the tension spring 210 is lowered as shown in the figure, the working circumferential length t of the tension spring 210 becomes short (and the above-mentioned pressing force is weakened).

The height of the constant speed rotating body 14 on the ancient road changes from the state shown in Figure 5B to the fifth position.
When pushed up as shown in Figure A, the working length t of the tension spring 21
becomes longer, and the above-mentioned pressure bonding force is strengthened.

Therefore, in this device, the length t of the tension spring 21 used can be varied by varying the height of the constant speed rotating body 14, so that the friction torque and the winding torque can be varied.

Next, to explain the actual tape tension adjustment operation on the winding side in FWD mode (recording or playback), first, the rotational torque of the motor is applied to the constant speed rotating body 1 through the FWD idler 24.
4, the constant speed rotating body 14 is driven to rotate at a constant speed.

As described above, the take-up reel stand 4 is driven to rotate by the friction torque between the control rotary body 13 and the friction plate 12, and the tape 6 is wound up by the take-up reel 5.

At this time, a predetermined tension is applied to the tape 6 between it and a capstan (not shown).

However, at this time, the tension detection lever 38 rotates around the fulcrum shaft 3γ in response to changes in the tape tension on the winding side that acts on the tension detection pin 39, but the value of the tape tension that acts on the tension detection pin 39 When is less than a predetermined value, the tension detection lever 38 is rotated clockwise in FIG. 3 by the spring force of the tension spring 42.
It is held in the position shown by the solid line in FIG. 3 when it comes into contact with the stopper 43.

As a result, the height of the constant speed rotating body 14 is set to a predetermined height via the variable torque lever 28 and the thrust bearing 26, thereby preventing the friction torque and, by extension, the winding torque from decreasing more than necessary. ing.

On the other hand, when the value of the tape tension acting on the tension detection pin 39 exceeds a predetermined value, the tension detection lever 3
8 is rotated counterclockwise against the tension spring 42 as shown by the chain line in FIG.

Then, the variable torque lever 28 is rotated clockwise as shown by the chain line in FIG. 3 via the long hole 40 and the interlocking pin 41.

At this time, due to the cam action of the inclined cam surfaces 30 and 31 between the variable torque lever 28 and the guide 29, the variable torque lever 28 moves downward along the inclined cam surface 31 from the state shown in FIG. 5A to as shown in FIG. 5B. Move to.

As a result, the constant speed rotating body 14 supported via the thrust bearing 26 is moved downward as shown in FIG. 5B, and its height is lowered.

As a result, as described above, the working length t of the tension spring 21 is shortened, the friction torque and the winding torque are reduced, and the tension of the tape 6 is reduced.

In this apparatus, the above-described automatic tape tension adjustment operation is continuously performed during the tape winding operation, and the tape tension on the winding side is always accurately maintained at a predetermined state.

According to the friction clutch 8 and the friction torque control mechanism 9 described above, the friction torque can be increased by slightly changing the height and thrust direction position of the constant speed rotating body 14 by rotating the variable torque lever 280. Since the friction torque can be varied very effectively, the friction torque can be adjusted with an extremely small transmission torque based on the tape tension detection between the tension detection lever 38 and the variable torque lever 28, and the friction torque can be adjusted extremely smoothly and reliably according to the tape tension. Friction torque can be adjusted.

In the device described above, the thrust bearings 25 and 26 that produce rolling friction reduce thrust loss during driving and when varying torque.

In addition, the spheres 18 and 32 that are interposed between the inclined cam surfaces 16, 1γ and 30, 31 and appear through rolling friction are formed when the constant speed rotating body 14 and the control rotating body 13 rotate relative to each other and when the variable torque lever 28 rotates. It reduces time loss.

As described above, the present invention provides a friction torque system that includes a take-up reel stand, a friction clutch that is in contact with the lower part of the take-up reel stand via a friction plate, and a variable torque lever that is arranged at the lower part of the friction clutch. The tape winding device is configured such that the friction torque of the friction clutch can be controlled by arranging the tentacle leg mechanism on the same axis and controlling the rotation of the variable torque lever by means of a tape tension detection means. The friction clutch includes a control rotating body welded to the friction plate, and a constant speed rotating body that is opposed to the lower part of the control rotating body and is rotationally driven by a drive source, Inclined cam surfaces that are substantially parallel to each other are formed on the opposing surfaces of the control rotating body and the constant speed rotating body, and a sphere for rolling friction is interposed between the inclined cam surfaces. and a constant speed rotating body in opposite directions in the circumferential direction, and a spring is provided to urge the control rotating body to move upward by the guiding action of the inclined cam surface and the spherical body. However, the above friction torque control mechanism is
The variable torque lever has a disc part integrally provided and a fixed guide opposed to the lower part of the disc part, and the facing surfaces of the disc part and the guide are substantially parallel to each other. The inclined cam surfaces are shaped respectively, and spheres for rolling friction are interposed between the inclined cam surfaces, and the constant speed rotary body of the friction clutch is configured to have a circular shape of the variable torque lever of the friction torque control mechanism. This tape winding device is characterized in that it is mounted on a plate portion via a thrust bearing for rolling friction.

Therefore, according to the present invention, by controlling the rotation of the variable torque lever using the tape tension detection means, the disk portion of the variable torque lever is moved up and down by the guiding action of the inclined cam surface between the disk portion and the guide. The height of the constant speed rotating body is changed by changing the height of the constant speed rotating body, and as a result, the circumferential phase of the control rotating body with respect to the constant speed rotating body is changed by the spring, and the inclination between the control rotating body and the constant speed rotating body is changed. The friction torque can be effectively controlled by moving the control rotating body up and down using the guiding action of the cam surface, but in this case, the disc part of the variable torque lever is moved against the constant speed rotating body and the guide. On the other hand, the rotation of the variable torque lever is very light because it is in contact with the thrust bearing and the sphere through rolling friction with very low frictional resistance, and the rotation of the variable torque lever is controlled easily with an extremely weak force by the tension detection means. I can do it.

Also, since the constant speed rotating body and the control rotating body are in contact with each other through the sphere by rolling friction with very low frictional resistance, the phase of the control rotating body with respect to the constant speed rotating body can be adjusted by changing the height of the constant speed rotating body. By making a sensitive change, the control rotating body can be sensitively moved up and down.

Therefore, it is possible to sensitively detect minute fluctuations in tape tension and accurately control friction torque.

In addition, the constant speed rotating body that is rotationally driven by the drive source is supported by rolling friction with very low frictional resistance via a thrust bearing on the disc part, so the constant speed rotating body is supported on the disc part through a thrust bearing. In addition to being able to rotate extremely smoothly and stably, the rotational torque of the disc part that rotates as the tape tension changes is completely cut off by the thrust bearing, and the rotational torque is transferred to the constant speed rotating body. There is no influence on the rotation of the constant speed rotating body.

Therefore, uneven rotation is less likely to occur in the constant speed rotating body, and the friction torque is less likely to fluctuate.

[Brief explanation of the drawing]

The drawings show an embodiment in which the present invention is applied to a tape winding device for a VTR.
The figure is a vertical sectional view of the assembled state, FIG. 3 is a plan view of the same as above, FIG. 4 is a sectional view taken along the line tV-[V of FIG.
The figure is a schematic side view of main parts for explaining the operation. Also, in the symbols used in the drawings, 4 is a take-up reel stand, 5 is a take-up reel, 6 is a tape, 8 is a friction clutch, and 9 is a take-up reel stand.
10 is a clamping torque control mechanism, 10 is a tape tension detection mechanism, 12 is a friction plate, 13 is a control rotating body, 14 is a constant speed rotating body, I Ll 7,30° 31 is an inclined cam surface, 18.3
2 is a sphere, 21 is a tension spring, 26 is a thrust bearing, 28 is a variable torque lever, 2ga is a disc portion, and 29 is a guide.

Claims (1)

[Scope of utility model registration request] A take-up reel stand, a friction clutch that is in contact with the lower part of the take-up reel stand via a friction plate, and a friction torque control mechanism having a variable torque lever disposed at the lower part of the friction clutch are placed on the same axis. In the tape winding device, the friction torque of the friction clutch can be controlled by controlling the rotation of the variable torque lever by a tape tension detection means, wherein the friction clutch is in contact with the friction plate. a controlled rotating body, and a constant-speed rotating body that is opposed to the lower part of the controlled rotating body and is rotated by a drive source, and the control rotating body and the constant-speed rotating body are Inclined cam surfaces that are substantially parallel to each other are formed on opposing surfaces of the cam surfaces, and a sphere for rolling friction is interposed between the inclined cam surfaces. The friction torque control mechanism is configured by providing a spring that urges the control rotating body to rotate in opposite directions to move the control rotating body upward by the guiding action of the inclined cam surface and the spherical body. It has a disc part integrally provided with the variable torque lever and a fixed guide opposed to the lower part of the disc part, and the facing surfaces of the disc part and the guide are substantially parallel to each other. Inclined cam surfaces are formed respectively, and spheres for rolling friction are interposed between the inclined cam surfaces, and the constant speed rotating body of the friction clutch is formed by a disk of the variable torque lever of the friction torque control mechanism. A tape winding device characterized in that the tape winding device is configured by being placed on the winding section via a thrust bearing for rolling friction.