JPH0319073Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a novel reel drive body. For details, see video tape cassettes, PCM (pulse code modulation) audio cassettes, etc.
A reel drive body that is engaged with an engagement hole of a reel in order to transmit the rotational force of a drive unit for rotationally driving the reel in a tape cassette in which a reel wound with tape is housed in a cassette housing. Regarding this new reel, the eccentric movement of the reel can be extremely reduced, and the reel's posture will not be disturbed even if the axis of the reel drive body is slightly tilted with respect to the normal direction. The aim is to provide a driving body.

Prior Art Tape cassettes, in which a recording medium such as magnetic tape is wound around a reel and placed inside a cassette housing, are widely used as video tape cassettes, and PCM audio cassettes have also been developed. is being done.

And in such a tape cassette,
To rotate the reel, a reel drive body rotated by the drive unit is engaged with a cylindrical engagement hole formed in the center of the reel, thereby transferring the rotational force of the reel drive body to the reel. I'm trying to communicate it.

FIGS. 10 to 12 show conventional examples of such reel driving bodies.

In the figure, a is a tape cassette, and reels d and d on which magnetic tape c is wound are placed inside a cassette housing b.
(Only one of them is shown in the drawing) is rotatably housed. e is an insertion hole formed in the bottom surface of the cassette housing b.

f is a cylindrical engagement hole formed through the center of the reel d, and the inner peripheral surface of the engagement hole f is provided with engagement grooves g, g,... at equal intervals in the circumferential direction. is formed to extend along the axial direction.

h is the drive shaft of the reel drive body. Reference character i denotes a reel drive body, which is supported on the drive shaft h so as to be slidable and integrally rotatable. A coil spring j is fitted onto the drive shaft h and presses the reel drive body i upward. K is a stopper, which prevents the reel drive body i from coming off the drive shaft h.

The reel drive body i has a substantially cylindrical shape, and has engaging protrusions l, l, l, and l, extending along the axial direction on its outer circumferential surface.
...are integrally formed.

When the tape cassette a is installed in a predetermined position, the reel driver i is inserted into the engagement hole f of the reel d through the insertion hole e formed in the bottom surface of the cassette housing b. And the reel drive body i
The engagement protrusions l, l, . . . engage with the engagement grooves g, g, . . . formed in the engagement hole f. Therefore, when the drive shaft h rotates, the rotation is transmitted to the reel d via the reel driver i, causing the reel d to rotate.

Problems to be Solved by the Invention However, the conventional reel drive body i described above has several problems.

Considering the smooth engagement between the engagement hole f of the reel d and the reel driver i, it is better that the difference between the inner diameter of the engagement hole f and the outer diameter of the reel driver i is larger. Moreover, by doing so, the flatness of the reel d is not affected by the reel driving body i. That is, the attitude of the reel d is determined by the attitude of the tape cassette a mounted on the equipment, and is not affected by the attitude of the reel driver i.

However, if the difference between the inner diameter of the engagement hole f of the reel d and the outer diameter of the reel driver i is increased, the reel d
causes eccentric movement during rotation, causing the magnetic tape c
This may cause vibrations or disturbances in the winding of the magnetic tape c on the reel d. If the magnetic tape c vibrates while running, the recording head and magnetic tape c
This may cause a discrepancy with the recorded track above.
This may cause deterioration in recording and playback quality. Also,
Vibrations of the magnetic tape c and irregular winding on the reel d cause the magnetic tape c to come into strong contact with the inner surface of the cassette housing b, causing strong friction and increasing loss torque, causing fast forwarding (FF) and rewinding. (REW) or high-speed search ability, and furthermore, it causes various inconveniences, such as not being able to obtain an appropriate tape tension.

Therefore, by reducing the difference between the inner diameter of the engaging hole f of the reel d and the outer diameter of the reel driver i to reduce the looseness between the two, the above-mentioned adverse effects of the eccentric movement of the reel d can be reduced. However, this time, the attitude of reel d is affected by the attitude of reel driver i, and as shown in FIG. Then, the reel d also slopes following the slope of the reel driver i, and when the winding diameter of the magnetic tape c on the reel d becomes large, the magnetic tape c moves toward the cassette case b.
The loss torque increases due to contact with the inner surface of the
Another problem is that it is not possible to smoothly attach the tape cassette a to the drive mechanism of the recording/reproducing device.

Purpose of the invention Therefore, the present invention has been devised in view of the various problems encountered with the conventional reel drive body described above. To provide a new reel drive body that does not disturb the attitude of the reel even when the axis is somewhat inclined with respect to the normal direction.

Summary of the invention In order to achieve the above-mentioned purpose, the reel driver of the invention engages with a substantially cylindrical engagement hole provided in the center of the reel to transmit the rotational force of the drive unit to the reel. The reel driving body has a maximum outer diameter section at an intermediate position in the axial direction, and the outer diameter decreases as the distance from the maximum outer diameter section increases. It is characterized in that the diameter is slightly smaller than the inner diameter of the engagement hole of the reel.

Effect: Therefore, in the reel drive body of the present invention, eccentric movement of the reel can be suppressed by setting the outer diameter of the maximum outer diameter portion to a value close to the inner diameter of the engagement hole of the reel. In addition, the outer diameter of the reel drive body is maximum at the maximum outer diameter part, and the outer diameter decreases as you move away from the maximum outer diameter part, so the attitude of the reel drive body is slightly inclined. However, the attitude of the reel is not affected by the attitude of the reel driver, and many inconveniences caused by tilting the reel can be solved.

Embodiments Hereinafter, details of the reel driving body of the present invention will be explained according to illustrated embodiments.

FIRST EMBODIMENT FIGS. 1 to 6 show the first embodiment of the reel drive body of the present invention.
This is an example of the following.

In the figure, 1 is a reel stand equipped with a reel drive body (described later) according to the present invention. Incidentally, this reel stand 1 is installed in a recording and reproducing section of a PCM audio cassette.

Reference numeral 2 denotes a support shaft, and the support shaft 2 is erected on a boss member 4 fixed to a mechanical chassis 3 of a recording/reproducing device, and the reel stand 1 is rotatably supported on this support shaft 2.

5 is a base portion of the reel stand 1, and an upper portion 5a of the base portion 5 is formed in a regular hexagonal cross section;
In addition, a disk portion 6 having gear teeth on the outer periphery is integrally formed from a portion near the lower end.
It is rotatably supported by the support shaft 2 while being placed on the upper end of the boss member 4 . Reference numeral 7 denotes a brake drum section disposed outside the base shaft section 5, which is integrally formed in an upright manner from the upper surface of the disk section 6, and has a cylindrical shape that is short in the substantially axial direction.

8 is a portion near the upper end of the base shaft portion 5, that is,
This is an engagement shaft portion provided externally on the hexagonal column portion 5a so as to be rotated integrally with the base shaft portion 5, and this engagement shaft portion 8 is a reel drive body to which the present invention is applied. The outer shape of the engagement shaft portion 8 is approximately bead-shaped.
A maximum outer diameter portion 9 is located at the middle portion in the axial direction, and the outer diameter becomes smaller as the distance from the maximum outer diameter portion 9 increases in the vertical direction. Then, the engagement shaft portion 8
An engagement protrusion 10 extending in the axial direction is provided on the outer peripheral surface of the
10, 10 are formed at equal intervals in the circumferential direction. Further, a through hole 11 having a regular hexagonal cross section is formed in the axial center of the engaging shaft portion 8 . Then, the hexagonal column portion 5a of the base shaft portion 5 is inserted into the through hole 11, and thereby,
The engagement shaft portion 8 is coupled to the reel stand 1 so as to be able to rotate integrally therewith.

Reference numeral 12 denotes a cap part fitted onto the upper end of the base shaft part 5, and the cap part 12 is prevented from coming off upward by a retaining washer 13 which is engaged with the upper end part of the support shaft 2. ing. The cap portion 12 allows the base shaft portion 5 of the engagement shaft portion 8 to
It is prevented from coming off.

Reference numeral 14 denotes a coil spring, which is fitted onto the base shaft portion 5, its lower end is engaged in an annular recess 15 formed at the base end of the base shaft portion 5, and its upper end is engaged with the engagement shaft portion 8.
It abuts against the lower end surface of and is contracted between the two. Therefore, the engagement shaft portion 8 is connected to the coil spring 1.
4, a force to move upward is applied.

16 is a tape cassette, 17 is a tape reel rotatably arranged inside the tape cassette 16, and the tape reel 17 has a magnetic tape 18.
is wrapped. Note that another tape reel is disposed within the cassette housing 19 of the tape cassette 16, but is not shown.

A cylindrical engagement hole 20 is formed in the center of the tape reel 17, and the inner diameter of the engagement hole 20 is slightly larger than the outer diameter of the maximum outer diameter portion 9 of the engagement shaft portion 8. There is. Furthermore, engagement grooves 21, 21, . . . extending along the axial direction are formed on the inner circumferential surface of the engagement hole 20 at regular intervals in the circumferential direction. still,
The width of the engagement grooves 21, 21, . . . is considerably larger than the width of the engagement projections 10, 10, 10 provided on the engagement shaft portion 8.

When the tape cassette 16 is installed in the recording/reproducing section, the engaging shaft portion 8 of the reel stand 1
is engaged with the engagement hole 20 of the tape reel 17.
At this time, the engagement protrusions 10, 10, 1 of the engagement shaft portion 8
If the position of 0 does not match well with the position of the engagement grooves 21, 21, ... of the engagement hole 20, the engagement shaft portion 8 will not be inserted into the engagement hole 20, but in such a case,
The engagement shaft portion 8 is pressed downward by the lower end surface of the tape reel 17, compressing the coil spring 14 and displacing it downward. Then, the engagement shaft portion 8
is rotated, when the positions of the engaging protrusions 10, 10, 10 match the positions of the engaging grooves 21, 21, . , and the engaging protrusions 10, 10, 10 engage with the engaging grooves 21, 21, . Further, the bottom surface of the cassette housing 19 of the tape cassette 16 is placed on a positioning section (not shown) provided in the recording and reproducing section, so that its flatness with respect to the recording and reproducing section is maintained.

In the case of the engaging shaft portion 8 in the reel stand described above, the outer diameter of the maximum outer diameter portion 9 is the same as that of the tape reel 17.
Since the inner diameter of the engagement hole 20 of the engagement shaft portion 8 is slightly smaller than the inner diameter of the engagement hole 20, the maximum outer diameter portion 9 of the engagement shaft portion 8 is made slightly smaller than the inner diameter of the engagement hole 20.
0, and the tape reel 17 is maintained in a state of precise centering, that is, the axial center of the reel stand 1 and the axial center of the tape reel 17 coincide with each other during rotation. Eccentric movement at is prevented.

Furthermore, even if the axis of the engagement shaft portion 8 is set at (θ°) relative to the regular shaft 22 as shown in FIG. 6, the outer diameter of the engagement shaft portion 8 is at the position of the maximum outer diameter portion 9. The tape reel 17 has a maximum outer diameter and becomes smaller as it gets further away from the maximum outer diameter portion 9, so that parts other than the maximum outer diameter portion 9 do not come into contact with the inner circumferential surface of the engagement hole 20. It is not affected by the inclination of the mating shaft section 8, and can rotate while maintaining a correct posture relative to the cassette housing 19 and the recording/reproducing section.

Second Embodiment FIGS. 7 to 9 show the second embodiment of the reel drive body of the present invention.
This is an example of the following.

In this second embodiment, the engagement shaft portion 8A has a maximum outer diameter portion 9A at the middle portion in the axial direction, and the outer diameter decreases as the distance from the portion 9A increases. The outer peripheral surface of the mating shaft portion 8A has a spherical shape.

Therefore, the engagement shaft portion 8A according to this second embodiment
Even in this case, the maximum outer diameter portion 9A contacts the inner circumferential surface of the engagement hole 20 of the tape reel 17 in a substantially linear contact shape, and the tape reel 17 is accurately centered. tape reel 17
This has the advantage that the attitude of the engagement shaft portion 8A is not affected by the attitude of the engagement shaft portion 8A.

Effects of the Invention As is clear from the above description, the reel driver of the present invention transmits the rotational force of the drive unit to the reel by engaging with the approximately cylindrical engagement hole provided in the center of the reel. A reel drive body for
It has a maximum outer diameter section at an intermediate position in the axial direction, and the outer diameter becomes smaller as it gets farther away from the maximum outer diameter section, and the outer diameter of the maximum outer diameter section is the same as that of the engagement hole of the reel. It is characterized by being slightly smaller than the inner diameter.

Therefore, in the reel drive body of the present invention, by setting the outer diameter of the maximum outer diameter portion to a value close to the inner diameter of the engagement hole of the reel, eccentric movement of the reel can be suppressed. In addition, the outer diameter of the reel driver is maximum at the maximum outer diameter, and the outer diameter decreases as you move away from the maximum outer diameter, so even if the reel driver is tilted slightly, The attitude of the reel is not affected by the attitude of the reel driver, and many inconveniences caused by tilting the reel can be solved.

In addition, in the description of the above embodiment, the present invention is not explained.
Although the present invention is applied to a reel driver provided on a reel stand provided in a recording/reproducing section of a PCM audio cassette, the present invention is not limited to such a device. As a reel driver for
It goes without saying that the present invention can also be applied as a reel drive body for rotationally driving other tape reels.

In addition, the outer shape of the reel drive body is shown as an abacus-shaped one or a spherical one, but of course it is not limited to these shapes, and the outer shape of the reel drive body is It suffices if it consists of a small part.

[Brief explanation of drawings]

1 to 6 show a first embodiment in which the reel drive body of the present invention is applied to a reel drive body provided on a reel stand for rotationally driving a tape reel of a tape cassette. is a side view of the reel stand, Figure 2 is an exploded perspective view of the reel stand,
3 is a cross-sectional view of the reel driver engaged with the tape reel, FIG. 4 is a cross-sectional view taken along the line - in FIG. 3, and FIG. 5 is a cross-sectional view taken along the line - in FIG. Figure 6 is a sectional view for explaining the action, Figure 7
9 to 9 show a second embodiment of the reel driver of the present invention, FIG. 7 is a side view of the reel stand, FIG. 8 is a perspective view of the reel driver, and FIG. 9 explains the operation. 10 to 12 show a reel stand using a conventional reel driver, and FIG. 10 is a side view of the reel stand, and FIG. 11 is a cross-sectional view of the reel driver and tape reel. FIG. 12 is a sectional view for explaining the operation. Explanation of symbols, 8... Reel driver, 9... Maximum outer diameter part, 17... Reel, 20... Engagement hole, 8A
...Reel drive body, 9A...Maximum outer diameter part.

Claims (1)

[Scope of utility model registration request] A reel drive body that engages with a substantially cylindrical engagement hole provided in the center of the reel to transmit the rotational force of the drive unit to the reel, and has a maximum outer diameter portion at an intermediate position in the axial direction. The outer diameter is made smaller as the distance from the maximum outer diameter portion increases, and the outer diameter of the maximum outer diameter portion is slightly smaller than the inner diameter of the engagement hole of the reel. reel drive body.