JPS6040097B2 - Dual capstan drive device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dual capstan drive device in a dual capstan type tape drive mechanism.

The constant speed tape drive mechanism in a tape recorder has the advantage of suppressing changes in tape tension caused by changes in reel winding or unevenness in tape material, making it effective in countering uneven tape speed and wow/flatter. There is a dual capstan type.

Such dual capstan type drive mechanisms include a direct drive type in which the rotating shaft of the motor is directly the capstan axis, an idler drive type in which a power transmission mechanism is provided between the motor and the capstan, and a belt drive type. However, especially in high-end machines, the direct drive system has the advantages of no slip or vibration due to no power transmission mechanism, and high reliability as there are no consumable parts such as belts or idlers. is frequently used.

However, in a direct-drive dual capstan type drive mechanism, two motors are naturally arranged on the supply side and the take-up side, but each motor is controlled by its low-speed rotation. In order to smoothly control the drive while maintaining speed, each motor must be equipped with a speed detection device for speed control and a position detection device for detecting the relative position of the rotor and stator. Therefore, the driving structure becomes complicated and the cost becomes high. An object of the present invention is to provide a dual capstan drive device with a simplified drive mechanism, high precision, and low cost.

J The dual capstan driving device according to the present invention connects the first and second rotors so as to rotate synchronously, and complementary rotational moments act between the first and second rotors, respectively. The first and second coils are arranged to face the first and second rotors, respectively, in such a positional relationship that the rotation center axes of the first and second rotors are directly connected to the two capstans. The structure is as follows. Further, a speed detection means for detecting the rotational speed of the rotor or a two-position detection means for detecting the relative position of the rotor and the coil is provided only on one side of the first and second rotors. There is.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

2 FIG. 1 is a side view, partially in section, of an embodiment according to the present invention. In the figure,
The main shaft 1 is rotatably held by a main bearing 4 whose lower end is engaged with a thrust bearing 3a fixed to the stator base 2, and which is fixed to the stator base 2.
3. At the lower end of main shaft 1 is the main shaft. 5 is installed. An annular magnet 6a is fixed to the lower end concave portion of the main rotor 5. The annular magnet 6a is magnetized in the thickness direction so that different magnetic poles are arranged alternately in the circumferential direction. First phase coils 7a and 7b are disposed opposite to the three magnetic pole surfaces of the magnet 6a with a predetermined gap therebetween. On the other hand, the sub-shaft 8 is rotatably held by a sub-bearing 9 whose lower end engages with the thrust bearing 3b and is fixed to the stator base 2.

A sub-rotor 10 is attached to the lower end of the sub-rotor 10, and an annular magnet 6b magnetized in the thickness direction so that different magnetic poles are arranged alternately in the circumferential direction. is fixed. The magnet 6b is as dirty as the magnet 6a. Second phase coils 7c and 7d are arranged opposite to the magnetic pole surface of the magnet 6b with a predetermined gap therebetween. The main rotor 5 and the sub-rotor 10 are coupled by a belt 11 serving as coupling means so as to rotate in synchronization with each other. The coupling means is not limited to the belt 11, and for example, gears can also be used. The main and subshafts 1 and 8 can be used as they are as a capstan. First phase and second phase coils 7a, 7b and 7c
, 7d are switched and controlled by a control means, which will be described later, so that the rotors 5 and 10 always generate a rotational moment in the same direction no matter the rotation angle position, and the first and second phase coils are connected to the magnets 6a and 7d. 6b, they are arranged in a positional relationship as shown in FIG. 2 so that rotation moments act complementary to each other.

That is, depending on the rotational position of the rotor, no driving current is supplied to the coils, resulting in a dead center where no rotational torque is generated between each magnet and the coil. When the coil is at the dead center, rotational torque is generated between the other magnet and the coil, and both rotors cooperate to rotate smoothly. Further, for example, on the main rotor 5 side, position detection means 12a, 12b such as Hall elements for detecting the relative positions of the main rotor 5 and the second phase coils 7a, 7b, and the auxiliary rotor 10 and the second phase coils 7c, 7d are provided. (Second
(illustrated) is provided so as to be located in the magnetic field of the magnet 6a.

As shown in FIG. 3, the position detection means 12a and 12b have their outputs supplied to drive circuits 13a and 13b, respectively, and together with the drive circuits, the outputs are sent to the first and second phase coils 7a, 7b, 7c, and 7d. It constitutes a control means for switching and controlling the drive current of. Furthermore, an annular magnet 14 is fixed in the upper end recess of the main rotor 5 and is magnetized in the radial direction so that different magnetic poles are arranged alternately at a pitch of 4 mm in the circumferential direction. a detection element 15 that detects changes in the magnetic field of the magnet 14;
is provided. This magnet 14 and detection element 15
A speed detecting means for detecting the rotational speed of the rotor is constituted by the above. As described above, according to the present invention, since only one-phase drive coil is arranged to drive each rotor, the drive structure is simplified and it is substantially possible to use multiple axes and multiple coils.

Therefore, the capstan can be driven smoothly with less torque ripple. Further, since it is possible to drive and constant speed control both rotors by simply providing position detection means and speed detection means on one rotor side, costs can be reduced compared to the case where two motors are used. Furthermore, since both rotors rotate in synchronization, the tension within the loop becomes constant, improving the wow/flutter characteristics and the tape touch of the head. In addition, in the above embodiment, the case where the position detecting means and the speed detecting means are provided on the main rotor side has been described, but they may be provided on the sub-row side, or may be provided separately on the main and sub-row side. Of course.

[Brief explanation of drawings]

FIG. 1 is a side view including a partial cross section of an embodiment of the present invention, FIG. 2 is a diagram showing the positional relationship of the coils, and FIG. 3 is a circuit diagram of an example of the control means. Explanation of symbols of main parts, 1... Main shaft, 5
...Main rotor, 6a, 6b...Magnet, 7a,
7b, 7C, 7d...Coil, 8...Subshaft, 1
0...Sub rotor, 11...Belt, 12a, 12b・
...Position detection means. Our company/End of figure Figure 3

Claims (1)

[Claims] 1. A drive device for driving two capstans, comprising:
between first and second rotors including magnets, coupling means for coupling the first and second rotors so as to rotate in synchronization with each other, and each magnet of the first and second rotors; a stator including first and second coils disposed facing the magnet in a positional relationship such that complementary rotational moments act on the magnets; and control for controlling drive currents of the first and second coils. A drive device for a dual capstan, characterized in that the rotation center axes of the first and second rotors are directly connected to the two capstans. 2. The control means includes speed detection means for detecting the rotational speeds of the first and second rotors, and the speed detection means is provided on either one of the first and second rotors. A driving device for a dual capstan according to claim 1. 3. The control means includes position detection means for detecting the relative positions of the first and second rotors and the first and second coils, and the position detection means detects which of the first and second rotors 2. The drive device for a dual capstan according to claim 1, wherein the drive device is provided on one side of the dual capstan. 4. The dual capstan driving device according to claim 1, wherein the coupling means comprises a gear. 5. The drive device for a dual capstan according to claim 1, wherein the coupling means comprises a belt.