JP2510052Y2 - Power transmission mechanism - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission mechanism, and more particularly to a power transmission mechanism for rotating a reel of a magnetic tape in a magnetic tape recording / reproducing apparatus or the like.

[0002]

2. Description of the Related Art FIGS. 4, 5 and 6 are a longitudinal sectional view, a side view and a plan view of an example of a conventional power transmission mechanism applied to a so-called cassette tape recorder. In the power transmission mechanism of the same figure, the drive gear 3 is press-fitted and fixed to the upper end side of the drive shaft 2 of the motor 1 which rotates around A ₁ in the figure. Also, below the drive gear 3 of the drive shaft 2 in the figure, an arm 5'with a movable shaft 4 press-fitted and fixed to the other end.
The rotation center portion 5'a is rotatably supported.

A driven gear 6 which is engaged with and interlocks with the drive gear 4 is rotatably supported about A ₂ above the moving shaft 4 in FIG. Above the driven gear 6 of the moving shaft 4, a reel base drive mechanism 7 interlocked with the driven gear 6 is rotatably supported around A ₂ . The driven gear 6 and the reel base drive mechanism 7 are connected by interlocking the claw portions 6a and 7a.

Further, the driven gear 6 is always pressed downward in FIG. 4 by the spring 8 between the driven gear 6 and the reel base drive mechanism 7. An annular felt 11 is interposed between the arm 5 ′ and the driven gear 6, and the driven gear 6 always presses the arm 5 ′ via the felt 11 by the pressing force of the spring 8. The rotation of the driven gear 6 is suppressed by the mutual frictional force.

By suppressing the rotation of the driven gear 6 in this way, the rotational driving force of the driving gear 3 is increased.
When the gear 5 is transmitted to the arm 5, the driven gear 6 does not rotate first, and the rotational driving force causes the arm 5'to swing. Reel base driving mechanism 7, which is supported on the moving shaft by swinging operation of the arm 5 'is rotated in the R ₁ direction also R ₂ direction in FIG. 6 abuts against the reel base 9 or 10.

An outer ring member 7b made of rubber is arranged around the outer circumference of the reel base drive mechanism 7. The outer periphery of the outer ring member 7b has a cylindrical shape centered on A ₂ .

First and second reel stands 9 and 10 are provided in both the depth direction and the front direction of the reel stand drive mechanism 7 in FIG. These reel stands 9 and 10 are rotatably supported by two rotation axes A ₃ and A ₄ which are parallel to A ₁ and A ₂ , respectively. Above the center of each cylindrical shape of the reel bases 9 and 10, the centers of the two reels on which the magnetic tapes in the magnetic tape cassette are wound are fitted, respectively, by fitting portions 9a. 10a are provided respectively.

In the power transmission mechanism having the above construction, the drive shaft 2 is rotationally driven in the R ₁ or R ₂ direction, so that the arm 5 ′ has the same R direction as the rotational direction of the drive shaft 2.
_The reel base drive mechanism 7 is rotated in the ₁ or R ₂ direction, and is rotated in the opposite R ₂ or R ₁ direction. Further, the reel bases 9 and 10 on the side where the reel base drive mechanism 7 abuts are rotationally driven in the same R ₁ or R ₂ direction as the drive shaft 2. By the rotation of the reel bases 9 and 10, the magnetic tape in the cassette is wound around the reel mounted on the reel base 9 or the reel mounted on the reel base 10.

In the above conventional power transmission mechanism, a slight gap d is required between the upper surface of the rotation center portion 5'a of the arm 5'and the lower surface of the drive gear 3 in the figure. That is, without the gap d, the arm 5'is sandwiched between the drive gear 3 and the upper housing of the motor 1 in the figure. In such a configuration, since the arm 5 has no escape area, the arm 5 is always pressed by the drive gear 3, and the frictional resistance generated thereby impedes the smooth rotation of the drive gear 3 and thus the motor. 1 will consume extra power.

In order to provide the gap d in the process of assembling the power transmission mechanism, a spacer having the thickness of the gap d is interposed between the rotation center portion 5'a of the arm 5'and the drive gear 3. Then insert them into the drive shaft 2. In this way, the drive gear 3 is press-fitted and fixed to the drive shaft 2, and the rotation center portion 5a of the arm 5 is fixed to the drive shaft 2.
And then pull out the spacer. The void d is formed by such a process.

[0011]

In the conventional power transmission mechanism having the above-described structure, a standard motor which is commercially available is usually purchased in consideration of cost reduction, and therefore the length of the drive shaft 2 of the motor 1 is increased. Is predetermined. On the other hand, the drive shaft 2 of the motor 1 has a drive gear 3 and an arm 5 '.
Since the and are inserted in layers, the thickness of the arm 5'which is not directly driven to drive the reel bases 9 and 10 in the vertical direction in the figure is made as small as possible, and the limiting requirements when applying the motor 1 are made as small as possible. There is a need. That is, it is necessary to be able to handle even the short drive shaft 2.

However, if the thickness of the rotation center portion 5'a of the arm 5'is reduced, the length of the rotation center portion 5'a supported by the drive shaft 2 in the vertical direction in the figure becomes smaller. As a result, the left end portion of the arm 5 ′ in FIG. 4 is shaken in the X ₁ and X ₂ directions, and the relative positional relationship between the drive gear 3 and the driven gear 6 becomes unstable. Therefore, the meshing of the gears deteriorates, smooth driving cannot be performed, noise is generated from the meshing parts of the gears, and an extra impact is applied to the gears 3 and 6 to Life is shortened. Further, when the rotation direction of the drive shaft 2 changes and the arm 5'rotates, there is a problem that the horizontal plane of the figure swings and the smooth rotation of the arm 5'is impeded.

Further, it is conceivable to thin the drive gear 3 instead of thinning the rotation center portion 5'a as described above, but by making the drive gear 3 thin, the drive gear 3
However, there is a problem in that the press-fitting strength of the drive shaft 2 with respect to the drive shaft 2 is reduced, and thus the reliability of the power transmission mechanism is reduced.

Further, as described above, in the assembling process, the process of inserting and removing the spacers is required to form the gap d, which causes a problem that the process is complicated.

The present invention has been made in view of the above problems, and an object thereof is to provide a power transmission mechanism in which power is smoothly transmitted and the assembly process can be simplified.

[0016]

SUMMARY OF THE INVENTION The present invention is a drive shaft.
Drive gear attached to the
Power from the drive gear in conjunction with the dynamic gear and the driven gear
Is transmitted to one of the two reel stands.
Reel base drive mechanism that contacts and transmits power to the reel base
And one side is rotatably supported by the drive shaft and the other side is
The driven gear and the reel base drive mechanism are rotatably supported.
It consists of an arm that rotates in one direction of the drive shaft.
Therefore, the reel base drive mechanism is one of the two reel bases.
The drive shaft is rotated so as to come into contact with one side, and the other side of the drive shaft
In accordance with the rotation of the two reels
The arm is rotated so that it abuts the other of the tables.
In the power transmission mechanism having the structure,
Larger than the outer diameter of the drive shaft through which the shaft is inserted
Do not have two support parts that are formed with insertion parts of the threshold inner diameter.
The arm has a through hole press-fitted into the drive shaft.
Through the through hole of the drive gear secured to the shaft.
Through the two supports, between the two supports
The drive shaft is rotatably supported .

[0017]

Operation: The present invention has a power transmission mechanism arm having a through hole.
Pressed into the drive shaft and fixed to the shaft
Via the through hole of the drive gear between the two support portions,
It is possible to rotate the drive shaft by the two support parts.
Because it is a supported configuration, the arm is between the two supports.
, Through the drive gear fixed to the drive shaft, comparison
The structure is supported by the drive shaft over an extremely long distance.
It

[0018]

2 and 3 are a longitudinal sectional view and a side view, respectively, of an embodiment of a power transmission mechanism according to the present invention. FIG. 1 is a schematic perspective view of a part of FIG. 2 in order to show the gist of the present invention. In the figure, the same components as those of the conventional power transmission mechanism shown in FIGS. 4 to 6 are designated by the same reference numerals.

In the power transmission mechanism shown in the figure, a top plate 5c of a rotation center portion 5a of an arm 5 (the gear loading means) described later is used.
(One of the gear insertion portion or the two support portions) and the bottom plate 5f (the other of the gear insertion portion or the two support portions) are the through holes 3 of the drive gear 3 (the gear).
It is configured to be supported by the drive shaft 2 (the shaft) above and below in FIG.

As shown in FIG. 1, the arm 5 has a slightly narrower width in the left depth direction of FIG. 1 and has a circular tip, and a through hole 5b into which the moving shaft 4 is press fitted is provided near the center of the circle. It is the composition that was set. Further, the arm 5 is surrounded in a gate shape in the front right direction in the figure, and a rotation center portion 5a is formed. As shown in FIG. 1, the rotation center portion 5a is composed of a top plate 5c, a bottom plate 5f, and two side plates 5s vertically connecting the bottom plate 5f and the top plate 5c.

The distance from the lower surface of the top plate 5c in the figure to the upper surface of the bottom plate 5f is a slight width d (the predetermined length) to the height of the drive gear 3 in the vertical direction (the length of the through hole) in the figure. (Gap) is the length added. Further, the top plate 5c and the bottom plate 5f have through holes 5h ₁ and 5h through which the drive shaft 2 passes.
h ₂ (the shaft insertion portion) is provided respectively. The through holes 5h ₁ and 5h ₂ have an inner diameter slightly larger than the outer diameter of the drive shaft 2.

In the power transmission mechanism shown in the figure, the through hole 3 is formed in the central portion of the drive shaft 2 of the motor 1 which rotates about A _1.
h is press-fitted into the drive shaft 2 and the drive gear 3 is press-fitted and fixed. A top plate 5c and a bottom plate 5f of a rotation center portion 5a of the arm 5 are rotatably supported above and below the drive gear 3 of the drive shaft 2 in FIG. or,
The moving shaft 4 is press-fitted and fixed in the through hole 5b at the other end of the arm 5. The moving shaft 4 is parallel to A _1
The driven gear 6 is fixed around the moving shaft 4, and is driven above the movable shaft 4 in the same figure as the driven gear 4 to be engaged with and interlocked with the driving gear 4. The driven gear 6 is rotatably supported around A ₂ .

A driven gear 6 which is engaged with and interlocks with the drive gear 4 is rotatably supported around A ₂ above the moving shaft 4 in FIG. Above the driven gear 6 of the moving shaft 4, a reel base drive mechanism 7 interlocked with the driven gear 6 is rotatably supported around A ₂ . The coupling portion between the driven gear 6 and the reel base drive mechanism 7 is configured such that the claw portions 6a, 7a are projected so as to face each other, and the claw portions 6a, 7a are engaged with each other to be engaged. The drive gear 6 and the reel base drive mechanism 7 are connected to each other.

A compressed spring 8 is interposed between the driven gear 6 and the reel base driving mechanism 7, and the elastic restoring force of the spring 8 causes the driven gear 6 and the reel base driving mechanism 7 to move. Are respectively subjected to the force of pushing and expanding in the vertical direction of FIG. That is, the driven gear 6 is always shown in FIG.
Is pressed downward. Between the arm 5 and the driven gear 6, a ring-shaped felt 11 having the moving shaft 4 inserted in the center thereof is interposed, and the driven gear 6 is always kept by the pressing force of the spring 8. The arm 5 is pressed via 11. Due to this pressing force, the rotation of the driven gear 6 is suppressed by the frictional force between the driven gear 6, the felt 11 and the arm 5.

By suppressing the rotation of the driven gear 6 in this way, the rotational driving force of the driving gear 3 is increased.
When the gear 5 is transmitted to the arm 5, the driven gear 6 does not rotate first, and the rotation driving force causes the arm 5 to swing. The swinging movement of the arm 5, that is, the reel base drive mechanism 7 supported by the moving shaft 4 by rotating the arm 5 in the R ₁ direction or the R ₂ direction in FIG. Moved to the reel stand 9 or 10
Abut.

A predetermined gap is formed between the interlocking portions of the claw portions 6a, 7a of the driven gear 6 and the reel base drive mechanism 7, respectively, and within a certain angle range. Driven gear 6 and reel base drive mechanism 7
Each of them can rotate independently. Both ends of the spring 8 are fixed to the surfaces of the driven gear 6 and the reel base drive mechanism 7 that face each other.

In such a configuration, the gear 6 is caused by the impact exerted by the drive gear 3 when the motor 1 is stopped and the torque fluctuation (called cogging, which is uneven rotation due to a change in magnetic resistance) generated during the rotation of the motor 1. The claw portions 6a of the above are elastically deformed to absorb these impacts and torque fluctuations.
Therefore, the gear 6a has a function as a shock absorber. In this way, the impact and torque fluctuation exerted by the drive gear 3 are prevented from being directly applied to the reel base drive mechanism 7, and are prevented from being applied to the magnetic tape via the reel base drive mechanism 7 and the reel base. It Therefore, it is possible to avoid damaging the magnetic tape due to the impact and torque fluctuation, and to avoid so-called wow flutter (variation in signal frequency at the time of recording or reproducing caused by speed variation of the magnetic tape).

An outer ring member 7b made of rubber is arranged on the outer circumference of the reel base drive mechanism 7 over the entire circumference. The outer periphery of the outer ring member 7b has a cylindrical shape centered on A ₂ . Note that the outer ring member 7b is not shown in FIG.

First and second reel stands 9 and 10 are provided in both the depth direction and the front direction of FIG. 2 of the reel stand drive mechanism 7 (see FIG. 6). These reel stands 9 and 10 are rotatably supported by two rotation axes A ₃ and A ₄ which are parallel to A ₁ and A ₂ , respectively. The reel bases 9 and 10 have a cylindrical shape centering on the rotating shafts A ₃ and A ₄ having the same shape.

The reel table 9 and 10 is rotatably supported about the A _3, A _4, respectively, by the rotation shaft (not shown). Above the center of each cylindrical shape of the reel bases 9 and 10 in the figure, the centers of the two reels around which the magnetic tapes in the magnetic tape cassette are wound are respectively fitted into the fitting portions 9a and 10a. Is provided.

Next, the operation of the power transmission mechanism having the above structure will be described. For example, when the drive shaft 2 is rotationally driven in the clockwise direction R ₁ when viewed from above in FIG. 2, the drive gear 3 also rotates in the R ₁ direction (see FIG. 6). The rotational power is transmitted to the driven gear 6, but the rotation of the driven gear 6 is suppressed by the mutual frictional force between the driven gear 6 and the arm 5 via the felt 11 as described above. Therefore, the arm 5 is _first rotated in the R ₁ direction by the rotational drive force of the drive gear 3. As a result, the moving shaft 4 is moved in the depth direction of FIG. Therefore, the reel base drive mechanism 7 supported by the moving shaft 4 is also moved in the depth direction in the figure, and the reel base drive mechanism 7 is moved to the reel base 9
Abut the outer peripheral surface of the.

As a result, the arm 5 is locked so that it cannot rotate further, so that the driven gear 6 is fixed to the felt 1.
1 is rotated in the counterclockwise direction R ₂ against the frictional force between the arm 5 and the arm 5 and the rotational power of the driven gear 6 is transmitted to the reel base drive mechanism 7. It Therefore, the reel base drive mechanism 7 is rotationally driven in the R ₂ direction.

Due to the friction between the outer ring member 7b of the reel base drive mechanism 7 and the outer peripheral surface of the reel base 9, the reel base 9 receives rotational power from the reel base drive mechanism 7 and is rotationally driven in the R ₁ direction. . As described above, the rotation of the arm 5 is locked by the reel base drive mechanism 7 coming into contact with the reel base 9, whereby the driven gear 6 is moved to the felt 1.
It is rotationally driven in the counterclockwise direction R ₂ as viewed from above in FIG. 2 against the frictional force between the arm 5 and the arm 5. Due to the friction between the driven gear 6 and the arm 5 via the felt 11, the arm 5 always receives the rotational driving force in the R ₁ direction.
Therefore, the reel base drive mechanism 7 is always pressed by the first reel base 9. In this way, the frictional force between the reel base drive mechanism 7 and the reel base 9 is sufficiently maintained, and the rotation of the reel base drive mechanism 7 is reliably transmitted to the reel base 9.

The above operation is an operation when the drive shaft 2 is rotationally driven in the R ₁ direction.
_When driven to rotate in _two directions, the operation is completely opposite to the above. That is, the reel base drive mechanism 7 receives the power transmitted by the drive gear 3 and the driven gear 6 and is rotationally driven in the R ₁ direction. Further, the arm 5 is rotated in the R ₂ direction similarly to the drive shaft 2, and the reel base drive mechanism 7 is moved in the front direction of FIG. As a result, the reel stand 10 is rotationally driven in the R ₂ direction.

In this way, the drive shaft 2 is either R ₁ or R ₂
By being driven to rotate in the same direction, the reel base drive mechanism 7 is rotated in the opposite R ₂ or R ₁ direction, and the arm 5 is moved in the same R ₁ or R ₂ direction as the rotation direction of the drive shaft 2. The reel bases 9 and 10 on the side where the reel base drive mechanism 7 abuts are driven to rotate in the same R ₁ or R ₂ direction as the drive shaft 2. By the rotation of the reel bases 9 and 10, the magnetic tape in the magnetic tape cassette is wound on one reel mounted on the reel base 9 or wound on the other reel mounted on the reel base 10. Taken.

As described above, in the power transmission mechanism of this embodiment, the top plate 5 of the rotation center portion 5a of the arm 5 is as described above.
The distance between c and the bottom plate 5f is equal to the height of the drive gear 3 by a width d.
Therefore, the space d is formed between the upper surface of the bottom plate 5f of the rotation center portion 5a and the lower surface of the drive gear 3 in FIG. This gap d allows the bottom plate 5f of the rotation center portion 5a of the arm 5 to move vertically between the drive gear 3 and the upper casing of the motor 1 in the figure. Therefore, the frictional resistance generated between the drive gear 3 and the top plate 5c of the arm 5 and between the bottom plate 5f of the arm 5 and the housing above the motor 1 is caused by the arm 5 and the moving shaft supported by the arm 5. 4, frictional resistance generated by the minimum necessary load generated by the respective weights of the driven gear 6 and the reel base drive mechanism 7. Therefore, the smooth rotation of the drive gear 3 can be ensured, and the power consumed by the motor 1 can be minimized.

Further, by constructing the arm 5 as in this embodiment, the space d is formed in the process of assembling the power transmission mechanism.
It becomes easy to provide. That is, each through hole 5h of the top plate 5c and the bottom plate 5f of the rotation center portion 5a of the arm 5 is
₁ , 5h ₂ and the through hole 3h of the drive gear 3 are aligned with the centers of the top plate 5c, the bottom plate 5f, and the side plate 5s.
The drive gear 3 is inserted into the space surrounded by. In this state, the drive shaft 2 is sequentially inserted into the rotation center portion 5a of the arm 5 and the through holes 5h ₁ , 3h, and 5h ₂ of the drive gear 3, and the bottom surface of the bottom plate 5f of the arm 5 in FIG. 2 is inserted until it comes into contact with the upper housing of FIG.

As described above, by using the arm 5 of this embodiment, the drive gear 3 is moved to the rotation center portion 5a of the arm 5.
At the same time, by inserting and loading the drive shaft 2, a predetermined gap d can be formed as shown in FIG. Therefore, the predetermined gap d can be formed without using a separate spacer or the like, and the assembling process can be simplified.

Further, in the power transmission mechanism having the above structure, the thickness of the top plate 5c and the bottom plate 5f of the rotation center portion 5a of the arm 5 can be made as thin as possible in consideration of only mechanical strength. That is, even if the top plate 5c and the bottom plate 5f of the arm 5 are thinned in this way, since they are supported by the drive shaft 2 through the through hole 3h of the drive gear 3, they are driven up and down in FIG. Drive shaft 2 through a distance longer than the height of gear 3
Supported by. That is, from the bottom surface of the top plate 5c in FIG.
It is supported by the drive shaft 2 through the length of f to the upper surface in the figure.

Since the arm 5 is supported by the drive shaft 2 over a long distance in this manner, the stability of the drive shaft 2 of the arm 5 in the X ₁ and X ₂ directions is sufficiently ensured. Therefore, the relative positional relationship between the drive gear 3 and the driven gear 6 supported by the drive shaft 2 via the arm 5 is ensured, and the meshing of these gears becomes smooth, so that the gears move smoothly. No noise is generated from the bite part. Further, since the gears 3 and 6 are not unnecessarily impacted, the durability of the gears 3 and 6 can be improved. Further, when the rotation direction of the drive shaft 2 changes and the arm 5 rotates, the horizontal plane of the arm 5 in the figure is stable without swinging, so that the smooth rotation of the arm 5 can be realized. .

Further, as described above, the rotation center portion 5a of the arm 5 is
Even if the top plate 5c and the bottom plate 5f are thinned, the function of the power transmission mechanism is not hindered. Therefore, the top plate 5c and the bottom plate 5f can be made as thin as possible, and the length of the drive shaft 2 of the motor 1 can be reduced. It suffices that the length is slightly longer than the length for press-fitting the drive gear 3, so that the limiting requirements when applying the motor 1 can be minimized. Therefore, an inexpensive and high-performance motor can be applied.

The present invention is not limited to magnetic tapes, tape information recording media in general, and is not limited to information recording media, but may be tape or linear members used for other purposes wound on a reel. Of course, it can be applied to a mechanism for handling.

Further, the present invention is not limited to the arm 5 used for rotating the reel of the magnetic tape, but the power is transmitted from the shaft to another mechanism such as a shaft protruding from the housing such as a motor and a bearing. When a gear for performing the above is inserted, it can be applied as a gap forming means used for forming a predetermined gap between the gear and the casing of the motor or the like.

[0044]

According to the present invention, since the arm of the power transmission mechanism is supported by the drive shaft over a relatively long distance, the arm is more reliably and stably supported by the drive shaft, and thus the drive shaft is supported. The relative positional relationship between the fixed drive gear and the driven gear provided on the arm is stably maintained. As a result, the gears can be smoothly meshed between the driving gear and the driven gear. Therefore, it is possible to prevent generation of noise in which the gears rub against each other from the meshed portion of the gears.
Further, since the gears are smoothly meshed with each other, it is possible to prevent the occurrence of a phenomenon in which the gears give unnecessary impacts. Therefore, it is possible to improve the durability of the gear. Further, the occurrence of friction loss and the like in the power transmission between the gears is reduced as much as possible, so that the power transmission can be efficiently performed.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 3 is a side view of one embodiment of the present invention.

FIG. 4 is a vertical sectional view of a conventional example.

FIG. 5 is a side view of a conventional example.

FIG. 6 is a plan view of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Motor 2 Drive shaft 3 Drive gear (gear) 3h Through hole 5 Arm (gear loading means) 5a Rotation center part 5c Top plate (gear insertion part, one of two support parts) 5f Bottom plate (gear insertion part, The other of the two support parts) 5h ₁ , 5h ₂ through holes (shaft insertion part) 6 driven gear 7 reel stand drive mechanism 9, 10 reel stand

Claims (1)

(57) [Scope of utility model registration request] 1. A drive gear mounted on a drive shaft.
A driven gear that interlocks with the driving gear, and the driven gear
Power is transmitted from the drive gear in conjunction with
Power to the reel stand by contacting either one of the reel stand.
Drive mechanism for transmitting the reel, and the drive shaft on one side
Is rotatably supported by the driven gear and reel base on the other side.
It consists of an arm that rotatably supports the drive mechanism, and drives the reel base by rotating the drive shaft in one direction.
So that the mechanism abuts one of the two reel stands
The drive shaft is rotated, and the drive shaft is rotated in the other direction.
Of the reel base drive mechanism contacts the other of the two reel bases.
To the power transmission mechanism in which the arm is rotated so that
In the arm, the drive shaft is inserted through the drive shaft.
An insertion part with an inner diameter larger than the outer diameter of the shaft was formed.
The arm has two supporting parts, and the arm has a through hole press-fitted into the drive shaft.
Two through holes of the drive gear fixed to the shaft
Through the two support parts,
A power transmission mechanism that is rotatably supported by a moving shaft .