JPH0348742Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a reel shaft drive device for a tape recorder, and in particular, a reel shaft drive device for a tape recorder that absorbs torque fluctuations caused by cogging of the reel motor and improves wow and flutter. The purpose is to provide.

Generally, the reel shaft drive system of a cassette tape recorder operates during the recording and/or playback mode to transmit the rotation of the reel motor, and includes a first rotation transmission system incorporating a slip mechanism or torque limiter in the middle, and a first rotation transmission system that operates during the recording and/or playback mode. The second rotation transmission system operates at the same time and directly transmits the rotation of the reel motor without going through the slip mechanism. Recently, the reel shaft drive system has been simplified by using the slip operation of the reel motor itself, omitting the first rotation transmission system, and providing only the second rotation transmission system as the reel shaft drive system. A tape recorder has been proposed. but,
In this tape recorder, even during recording/playback, torque fluctuations of the reel motor are directly transmitted to the take-up reel shaft, and the tension of the tape wound on the take-up reel fluctuates relatively greatly.
This tension fluctuation has a negative effect on the running of the tape upstream of the pinching drive section formed by the pinch roller and capstan, resulting in a problem in that the wow and flutter characteristics deteriorate.

This problem becomes particularly noticeable when a reel motor is a core type motor that is prone to torque fluctuations. Further, this problem can be alleviated to some extent by using a coreless motor with less torque fluctuation, but since a coreless motor is expensive, the cost will be high.

The present invention solves the above problems, and one embodiment thereof will be described below with reference to the drawings.

FIG. 1 is a plan view of an embodiment of a reel shaft drive device for a tape recorder according to the present invention, and FIG. 2 is a cross-sectional view taken along the - line showing an enlarged view of the main parts of the present invention.

In each figure, 1 is a tape cassette, 2 is a take-up reel stand assembly, 3 is a supply reel stand assembly, 4 is a reel motor (iron core type motor), and 5 is an idler assembly.

As shown in FIG. 3, the idler assembly 5 includes a first idler 9 which is supported on a shaft 7 at the tip of a swing arm 6 and is in contact with a motor pulley 8.
and a second idler 10 which is superimposed on the first idler 9 and is also rotatably supported on the shaft 7 and can abut against the take-up reel stand assembly 2 or the supply reel stand assembly 3;
The bent portion 11a at the lower end is locked in the locking hole 9a of the first idler 9, and the bent portion 11b at the upper end is locked in the locking hole 10a of the second idler 10, so that the first idler 9 and the second idler 9 are connected to each other. The torsion coil spring 11 is provided between the idler 10 of No. 2 and acts as a torsion spring and a compression coil spring. 12
is a washer to prevent it from coming off. Reference numeral 13 denotes a felt, which is pressed against the first idler 9 by the elastic force of the torsion coil spring 11 and rotates into the swing arm 6.
generates a frictional force for swinging motion of the motor pulley 8 depending on the direction of rotation.

Further, the first idler 9 is formed with a protrusion 9b extending in the radial direction, and the second idler 10 is formed with a groove 10b extending in the radial direction. As shown in FIG. 4, they are fitted with a large gap _g1 so that they can rotate independently within a certain angular range. The protruding portion 9b and the groove portion 10b abut each other during the fast-forward mode, as will be described later.

Further, the above-mentioned swing arm 6 is pivotally supported by one end of a rotating arm 16 which is pivotally supported by a pin 15 on a mounting plate 14 to which the reel motor 4 is mounted. The rotating arm 16 is urged to rotate clockwise by a spring 17, and the first idler 9 presses against the motor pulley 8.

As shown in FIGS. 1 to 3 and 5, the take-up reel stand assembly 2 has a guide shaft 20 in the center having protrusions 20a, 20b, 20c along the axial direction at 120 degree intervals on the outer circumference. A reel stand 21 that is planted,
It is composed of a reel shaft 22 of a molded product fitted to the guide shaft 20, and a coil spring 23 fitted around the guide shaft 20 and biasing the reel shaft 22 upward. The reel shaft 22 has an internal hole 23d having grooves 22a, 22b, and 22c at 120 degree intervals on the circumferential surface, and a bending elastic deformation hole 23d extending downward at 120 degree intervals on the outer periphery of the lower surface, which is the essential part of the present invention. It has possible long legs 22e, 22f, and 22g. The long legs 22e, 22f, and 22g are integrally molded with the reel shaft 22. The grooves 22a to 22c are the protrusions 20
The width of the groove is such that the grooves a to 20c are fitted with a gap g ₂ in the circumferential direction. The long legs 22e to 22g have hook portions 22 _e-1 , 22 _f-1 , and 22 _g-1 at their lower ends. The reel shaft 22 has grooves 22a to 22c each formed with a protrusion 20a.
〜20c, the hole 20d is the guide shaft 20
The hooks 22 _e-1 to 22 _g-1 at the lower ends of the long legs 22 e to 22 g are fitted into the corresponding holes 21 a, 21 b, and 21 c of the reel stand 21 so that they cannot come out. and is pushed upward by a coil spring 28.

The rotation of the reel stand 21 is transmitted to the reel shaft 22 via the long legs 22e to 22g.
g functions as a buffer that elastically deforms in the circumferential direction when the torque of the reel stand 21 fluctuates and absorbs the torque fluctuation.

Next, the operations of the idler assembly 5 and the take-up reel stand assembly 2 in the recording or reproducing mode will be described.

During recording or playback mode, as shown in Figure 1,
The magnetic tape 30 is held and driven by a pinch roller 31 and a capstan 32, is pulled out from the tape winding body 33 on the side of the supply reel stand assembly 3, and runs along an erasing head 34, a recording/reproducing head 35,
The magnetic tape 30 fed out from the nipping drive unit is wound around the tape winding body 36 on the take-up reel stand assembly 2 side, which is rotated by the reel motor 4 through the idler assembly 5 in the tape winding direction shown by arrow A. taken.

The rotation of the motor pulley 8 in the direction of arrow B is transmitted to the first idler 9, which rotates in the direction of arrow C. The rotation of the first idler 9 is transmitted to the second idler 10 via the torsion coil spring 11. In the state shown in the figure, in which the protruding strip 9b is separated from the side wall of the groove 10b and rotates substantially integrally with no rotation transmission in this part, the rotation of the second idler 10 is transmitted to the reel stand 21. This rotates in the direction of arrow A. The reel stand 21 is rotated by the long legs 22e~
22g to the reel shaft 22, and the reel shaft 22 is connected to the guide shaft 20 with grooves 22a to 22c having gaps on both sides and the protrusion 2.
0a to 20c, that is, this portion rotates in a state where no rotation transmission action is performed.

When the reel motor 4 causes cogging or the like and the torque fluctuates, this torque fluctuation is transmitted to the first idler 9, but the torsion coil spring 11 is elastically deformed in the direction of diameter reduction, thereby reducing the torque fluctuation. This is absorbed, and the second idler 10 rotates with almost no torque fluctuation. Even if a torque fluctuation occurs in the second idler 10, this torque fluctuation is absorbed by being deflected in the circumferential direction when transmitting the long legs 22e to 22g, and the reel shaft 22 is absorbed by the torque fluctuation. Rotates without. Therefore, the tension T of the magnetic tape 30 wound around the tape winding body 36 is also kept constant without fluctuation.
This eliminates deterioration of wow and flutter characteristics.

That is, torque fluctuations of the reel motor 4 are absorbed in two stages during the process of being transmitted to the reel shaft 22, the reel shaft 22 rotates without torque fluctuations, and good wow and flutter characteristics are maintained.

Note that when the torsion coil spring 11 operates to absorb torque fluctuations, the relative angle between the first and second idlers 9 and 10 will change somewhat, but this change in relative angle is due to 9b is groove 10
This is done by rotating and displacing within b. Further, when the long legs 22e to 22g operate to absorb torque fluctuations, the relative angle between the reel stand 21 and the reel shaft 22 changes somewhat, but this change in relative angle is due to the fact that the protrusions 20a to 20c are This is done by rotational displacement within 22c.

In addition, in the fast-forward mode in which a large tape winding torque is required, the protrusion 9b abuts against the side wall of the groove 10b as shown by the two-dot chain line in FIG. The ridges 22a to 22c are connected directly to the idler 10 of
The reel stand 21 and the reel shaft 22 are directly connected to each other by abutting against the side wall of the reel 22c, and the reel shaft 22 is directly driven by the reel motor 4. Regarding the torsion coil spring 11 and the long legs 22e to 22g, excessive deformation is prevented during the fast forward mode. Especially long legs 22e~22g
This prevents excessive bending and breakage.

In the rewinding mode, the idler assembly 5 swings as shown by the two-dot chain line in FIG. 1, comes into contact with the supply reel stand assembly 3, and rotates it in the tape winding direction. At this time as well, the first idler 9 and the second idler 10 rotate in a directly coupled state as in the above-described fast forward mode.

Furthermore, it goes without saying that the device of the present invention can also be applied to a tape recorder configured to perform recording and reproduction even when the tape is run in the opposite direction.

As described above, according to the reel shaft drive device for a tape recorder according to the present invention, the long legs within the reel stand assembly bend and elastically deform to absorb fluctuations in the driving force of the reel motor, so that torque fluctuations are not caused to the reel motor. Even if this torque fluctuation occurs, this torque fluctuation is absorbed by the long leg, and the reel shaft rotates without torque fluctuation.This suppresses the tension fluctuation of the tape wound onto the tape winding body, and ultimately eliminates wow and flatness. It is possible to prevent the characteristics from deteriorating, and in other words, it is possible to maintain good wow and flutter characteristics even when an inexpensive iron core type motor that is prone to torque fluctuation is used as a reel motor.

Furthermore, since the long legs are integrally molded with the reel shaft, the number of parts can be reduced compared to the case where a torsion coil spring is used.

[Brief explanation of drawings]

FIG. 1 is a plan view of an embodiment of a reel shaft drive device for a tape recorder according to the present invention, and FIG. 2 is an enlarged view of the essential parts of the present invention in FIG. 1. 3 is an exploded perspective view of the idler assembly and take-up reel stand assembly shown in FIG. 2, and FIG.
FIG. 2 is an enlarged cross-sectional view taken along the line - in FIG. 2 showing the engagement state between the idler and the second idler; FIG. It is a sectional view along the center line. 1: Tape cassette, 2: Take-up reel stand assembly, 3: Supply reel stand assembly, 4: Reel motor, 5: Idler assembly, 6: Swing arm, 8:
Motor pulley, 9: first idler, 9a: locking hole, 9b: protrusion, 10: second idler, 10
a: Locking hole, 10b: Groove, 11: Torsion coil spring, 11a, 11b: Bent portion, 20: Guide shaft, 20a to 20c: Projection, 21: Reel stand, 2
1a, 21b, 21c: hole, 22: reel shaft, 2
2a to 22c: groove, 22d: hole, 22e to 22
g: long leg, 22 _e-1 , 22 _g-1 : hook portion, 30: magnetic tape, 31: pinch roller, 32: capstan, 33, 36: tape winding body, 34, 35: head.

Claims (1)

[Claims for Utility Model Registration] A reel shaft drive device for a tape recorder in which the driving force of a reel motor is transmitted to a reel shaft to drive the reel shaft, comprising: a reel stand rotated by the reel motor; The reel shaft is provided coaxially with the reel shaft on the table, and the reel shaft is formed integrally with the reel shaft and extends downward from the lower outer periphery, and the lower end side is engaged with the reel table and can be elastically deformed. A reel shaft drive device for a tape recorder, comprising: a reel stand assembly comprising a long leg, the long leg being elastically deformed by bending in response to fluctuations in the driving force of the reel motor.