JPH10289505A - Capstan motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a tape from being rolled in between a housing and a capstan shaft at the time the tape is slacked by providing angle at the shape of the cross section of the support of the capstan housing so that the distance between a tape running surface and the housing become larger as the tape approaches the post of a shaft outgoing side. SOLUTION: The shape of the cross section of a capstan housing 17 is made to have an angle θ in a direction in which the distance between the post 23 of the shaft outgoing side and a housing 17 becomes larger in the positional relation between a tape running surface X consisting of a capstan shaft 2 and the next post 23 and the housing surface Y opposing to the surface X. Thus, at the time of the slacking of a tape 1, it is prevented that the tape 1 is brought into contact with the housing 17 at a part very near the shaft 23 of the tape and the tape 1 is rolled in between the housing 17 and the shaft 2. Besides, at the time of a tape running, since the gap between the tape 1 of the post 23 side and the housing 17 become large, even when the position of the post 23 is fluctuated, the housing 17 and the tape 1 are not brought into contact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capstan motor used for a VTR or the like, and more particularly to a housing structure for supporting a capstan motor shaft.

[0002]

2. Description of the Related Art Conventionally, in a recording or reproducing apparatus such as a VTR using a tape as a medium, a capstan motor is used as a power source for driving the tape. First, a general tape drive principle of a VTR will be described with reference to FIG. In the figure, 1 is a recording medium tape, 2 is a capstan shaft, 3 is a pinch roller, 4
Is a rotary drum on which a head is mounted, 5 is a tension post, 6 is a take-up reel stand (hereinafter referred to as a T reel stand), 7
Is a supply reel base (hereinafter referred to as an S reel base), 8 is a reel drive gear, 9 is an idler gear, 1a is a take-up tape wound on a take-up reel on a T reel base 6, 1b is S
The supply side tape is wound around a supply reel on the reel base 7.

The tape 1 is pulled out from a cassette (not shown), and forms a tape path in a state shown in FIG. 4 where recording and reproduction are possible. At the time of recording and reproduction, the tape is sandwiched between the capstan shaft 2 and the pinch roller 3 and the rotation of the capstan shaft 2 is controlled so that the tape 1 travels in the direction of the arrow at a constant speed. Is recorded and reproduced.

On the other hand, the tape 1 fed at a constant speed by the capstan shaft 2 is wound by an idler gear 9 driven by a capstan motor by a T-reel base 6 which is driven to rotate via a reel base drive gear 8. Can be When the tape 1 runs in the reverse direction, the idler gear 9
Is wound by an S-reel table 7 which is driven to rotate via a reel table driving gear 8.

Next, the structure of the capstan motor will be described. FIG. 5 shows a vertical sectional view of the capstan motor. 2 is a capstan shaft, 10 is a coupling boss, 11
Is a rotor yoke, 12 is a drive magnet, 13 is a rotation detecting magnet, 14 is a stator yoke, 15 is a flexible board, 16 is a drive coil, 17 is a capstan housing, 18 (18a, 18b) is a metal bearing, 19
Is a thrust receiver, 20 is a thrust receiver holder, 21a, 21
b denotes an oil stopper, and 22 denotes a rotor rotation detecting sensor.

[0006] The capstan shaft 2 is connected to a coupling boss 10.
, A drive magnet 12 is arranged in the rotor yoke, and a rotation detecting magnet 13 is arranged on the outer periphery of the rotor yoke, thereby constituting a rotor unit.

On the other hand, the capstan shaft 2 is supported by metal bearings 18a and 18b.
a, 18 b are integrated with the housing 17. A stator yoke 14 having a flexible board 15 is fixed to the coupling boss 10 side of the housing 17, and a drive coil 16 arranged opposite to the drive magnet 12 is attached to the flexible board 15. In the housing 17, a thrust receiver 19 and a thrust receiver holder 20 are fixed to the tip end side of the capstan shaft 2, and the capstan shaft 2 is supported by the thrust receiver 19 in the thrust direction. Metal bearing 18a, 18
The capstan motor is rotatably supported by b and the thrust receiver 19, and the capstan motor generates a driving force by a rotational force obtained by flowing an exciting current to the driving coil 16. The stator yoke 14 has a rotor rotation detecting sensor 2.
2, the sensor 22 detects the magnetic force of the rotation detecting magnet 13 so that the rotation speed of the rotor unit can be read.

An oil stopper 21a is arranged on the capstan shaft 2 on the coupling boss side of the metal bearing 18a, and an oil stopper 21b is arranged on the tip side of the capstan shaft 2 of the metal bearing 18b. The structure is such that oil leaking from the metal bearing does not flow into the tape running surface. Also, the capstan housing 17
As shown in FIG. 6, the cross section of the housing 17 has a shape parallel to the contour Y of the housing 17 facing the tape running surface X after the capstan shaft 2 during tape running.

[0009]

However, in the above-mentioned conventional example, since the positions of the posts after the capstan shaft 2 vary, it is necessary to provide a predetermined distance between the tape running surface X and the housing surface Y. If the interval is too large, as shown in FIG. 7, when the tape becomes slack, the tape is entangled in the gap between the capstan shaft 2 and the housing 17 and damages the tape.

[0010] Here, the tape sags for the following reason. That is, when the tape feed is switched in the forward direction (S reel table → T reel table) from the tape reverse running (T reel table → S reel table), the capstan motor switches from reverse rotation to normal rotation, and the capstan motor rotates. The tape pressed to the shaft and the pinch roller is sent to the capstan exit side. However, the wound-up tape is taken up by the T reel base 6 by the idler gear 9,
Since the swinging of the idler gear from the S reel base to the T reel base is performed by switching to the normal rotation of the capstan motor, the winding operation is delayed. As a result, the tape sags on the exit side of the capstan motor.

When the distance between the tape running surface X and the housing surface Y is set small, as shown in FIG. 8, the tape moves to the housing 17 during tape running due to an error in the position of the post after the capstan shaft 2. There has been a problem that the tapes come into contact with each other and good tape running becomes impossible.

Here, the reason why the position of the delivery side post varies is as follows. That is, the capstan exit side post 23 is a post located on the back coat side of the tape as can be seen from the tape path in FIG. And post 2
Reference numeral 3 denotes a movable post which is located inside the tape when the cassette is loaded, and moves to the position shown in FIG. 4 while pulling out the tape when recording and reproducing the tape. For this reason, post 2
In No. 3, the position varies with respect to the capstan shaft position due to the accuracy of the movable mechanism.

Accordingly, it is an object of the present invention to prevent the tape from being wound between the housing and the capstan shaft when the tape is slack, while ensuring good tape running irrespective of the variation in the position of the movable post. .

[0014]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a tape driving system in which the shape of a cross section of a column of a housing of a capstan motor moves toward a post on a shaft exit side with respect to a tape running. An angle is provided so that the distance between the surface and the housing is increased.
In the above configuration, by shortening the distance between the tape and the housing in a portion near the capstan shaft,
The tape can be prevented from being wound between the capstan housing and the shaft when the tape is slack, and a desired distance can be secured in a portion far from the capstan shaft. , And good tape running can be realized.

[0015]

Next, embodiments of the present invention will be described. Figures 1-3
FIG. 1 is a drawing that best illustrates the features of the present invention. FIG. 1 is a cross-sectional view of a capstan housing 17, FIG. 2 is a vertical cross-sectional view of a capstan motor, and FIG. ing. The entire configuration of the capstan motor is substantially the same as the conventional example described with reference to FIGS. 4 and 5, and the same components are denoted by the same reference numerals and description thereof will be omitted.

In this embodiment, the cross section of the capstan housing is shaped as shown in FIG.
The tape running surface X including the post 23 and the next post 23 and the housing surface Y facing the tape running surface X have an angle in a direction in which the distance between the post on the shaft exit side and the housing is increased. As shown in FIG. 3, when the tape is slackened, the tape comes into contact with the housing at a portion very close to the shaft, and the tape can be prevented from being wound between the housing and the shaft.

On the other hand, when the tape is running, the position of the post 23 which comes to the next position on the tape exit side of the shaft varies due to an error. However, there is no contact between the housing and the tape.

[0018]

As described above, according to the present invention,
The cross-sectional shape of the capstan housing should be such that the distance between the housing and the tape running surface increases with the distance from the tape running surface consisting of the capstan shaft and the post on the tape output side of the capstan shaft toward the outlet post. By providing an angle in the shape of the housing surface facing the running surface, the gap between the capstan shaft and the housing can be reduced, and the distance between the tape and the housing near the post on the tape exit side can be increased,
In addition to preventing the tape from being wound between the housing and the shaft when the tape is slack, stable tape running can be realized irrespective of the positional error of the post on the shaft exit side.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a housing of a capstan motor according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the capstan motor according to the embodiment of the present invention.

FIG. 3 is a diagram showing a state near a housing when the tape is slackened in the embodiment of the present invention.

FIG. 4 is a tape path diagram of a conventional VTR.

FIG. 5 is a longitudinal sectional view of a conventional capstan motor.

FIG. 6 is a cross-sectional view of the vicinity of a conventional housing.

FIG. 7 is a view showing the vicinity of the housing when the tape is slackened in the conventional example.

FIG. 8 is a view showing the vicinity of a housing during tape running in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Tape 2 Capstan shaft 3 Pinch roller 4 Drum 5 Tenregi post 6 T side reel stand 7 S side reel stand 8 Reel drive gear 9 Idler gear 10 Coupling boss 11 Rotor yoke 12 Drive magnet 13 Rotation detection magnet 14 Stator yoke 15 Flexible board 16 Drive Coil 17 Housing 18 Metal bearing 19 Thrust receiver 20 Thrust holder 21 Oil stop 22 Rotation detection sensor 23 Shaft exit side post

Claims (1)

[Claims] 1. A rotor unit comprising a capstan shaft provided with a multi-polarized rotor magnet via a coupling bush and a rotor yoke, and a plurality of coils disposed at predetermined positions facing the rotor unit. A capstan motor fixed to a bearing housing that supports the capstan shaft, wherein the post is a post of the capstan housing facing a tape running surface formed by the capstan shaft and the next post on the shaft exit side. A capstan motor characterized in that an angle is provided so that the distance between the tape running surface and the housing increases as the shape of the portion approaches the post on the shaft exit side.