JPH11122969A - Drive device and method using motor and/or storage and/ or reproducing device of shaped-storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device using a motor that detects the speed of the motor and can accurately vary the number of coil windings of the motor. SOLUTION: A device has a motor 30 for switching the number of coil windings of coils 32-34, where a drive current flows to at least 2, transistors 35-44 for switching the number of the coil windings of the coils 32-34 of the motor 30 and driving the motor 30, and a speed detection part 51' for detecting the speed of motors 32-34, based on the back electromotive voltage of the motors 32-34. It also has a motor control part 50, where the motor control part 50 controls the transistors 35-44, while reducing the number of coil windings of the coils 32-34 for rotating the motor 30, based on the speed detected by the speed detection part 51 when the difference in speeds between the cases where the number of the coil windings of the coils 32-34 is small and where the number of the coil windings is larger than a specific threshold.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driving apparatus and a driving method using a motor for controlling the rotation speed of a motor constant, and a tape for controlling the rotation speed of a motor used for a running system of a tape-shaped recording medium. The present invention relates to a recording and / or reproducing apparatus for a recording medium.

[0002]

2. Description of the Related Art A portable tape recorder uses, for example, a dry battery or a rechargeable battery as a power source. In such a tape recorder, when the battery voltage is reduced due to the use of the device, the number of rotations of the motor decreases, and the running speed of the magnetic tape cannot be maintained constant. In order to keep the running speed of the magnetic tape constant, various measures have been devised in this type of tape recorder. For example, the number of windings of a motor is switched by a battery voltage.

More specifically, such a tape recorder has, for example, a three-phase DC motor provided with an intermediate tap in the middle of each phase winding (hereinafter, referred to as a coil), and a drive flowing through each phase coil. And a drive circuit for driving the motor while changing the current path according to the battery voltage. Here, the mode in which the drive current flows through the entire coil to rotate the motor, that is, the operation mode in which the number of turns of the coil in which the drive current actually flows is the first mode, and the drive is performed only between one end of the coil and the intermediate tap. A mode in which a current flows to rotate the motor, that is, an operation mode in which the number of windings is small is defined as a second mode.

[0004] The drive circuit includes a motor drive unit including a transistor for switching a drive current flowing through the coil, a rotation speed detection unit for detecting the rotation speed of the motor based on the cycle of the back electromotive voltage of the coil, and a rotation speed detection unit. A motor control unit that controls the motor drive unit according to the detected number of rotations.
Then, the motor control unit selects the first mode when the rotation speed of the motor is the predetermined rotation speed based on the rotation speed of the motor detected by the rotation speed detection unit, and determines that the rotation speed of the motor is the predetermined rotation speed. If less, select the second mode.

In such a tape recorder, when the play button is pressed, first, the motor is driven in the first mode. Here, when the rotation speed detected by the rotation speed detection unit is a predetermined rotation speed, the motor control unit controls the motor driving unit to maintain the first mode. Then, the motor control unit is configured to switch the motor to the second mode when the tape recorder is used and the battery voltage decreases, and the rotation speed detected by the rotation speed detection unit becomes lower than a predetermined rotation speed. Control the drive. That is, when the battery voltage drops and the motor rotation speed cannot be maintained at the predetermined rotation speed, the motor control unit selects the second mode having a small number of windings of the coil to increase the drive current flowing through the coil. Then, the rotation speed of the motor is set to a predetermined rotation speed.

[0006]

To switch between the first mode and the second mode, for example, a predetermined number of revolutions is recorded in a memory or the like of a motor control unit, and the recorded predetermined number of revolutions and actual The change is performed by comparing the detected number of rotations of the motor, and a change of 1% to 2% of the actual number of rotations is detected. By the way, the rotational speed of the motor has a manufacturing error of each motor such as a variation at the time of setting the rotational speed of the motor, and in addition, there is a variation in load caused by a temperature change. May also be large. In such a case, it is indistinguishable whether the decrease in the number of revolutions of the motor is due to a decrease in the battery voltage or due to a manufacturing error, a temperature change, or the like. Sometimes it cannot be done accurately.

Accordingly, the present invention provides a driving device using a motor, a driving method using the motor, and a recording method for a tape-shaped recording medium, which can detect the number of rotations of the motor and accurately change the number of windings of the motor. And / or to provide a playback device.

[0008]

In order to solve the above-mentioned problems, a drive apparatus using a motor according to the present invention has a motor capable of switching at least two or more windings of a coil through which a drive current flows. Driving means for driving the motor by switching the number of windings of the coil of the motor, rotation number detecting means for detecting the number of rotations of the motor based on the cycle of the back electromotive voltage of the coil, and rotation number detection means. When the difference between the number of rotations when the number of windings of the coil is small and the number of rotations when the number of windings is large is larger than a predetermined threshold based on the number of rotations, the number of windings of the coil is reduced and the motor is rotated. And control means for controlling the driving means.

Further, in order to solve the above-mentioned problems, the driving method using the motor according to the present invention has the steps of driving a motor capable of switching at least two or more windings of a coil through which a driving current flows. The process of detecting the number of rotations of the motor when the number of windings of the coil is small and the number of rotations of the motor when the number of windings of the coil is large; The method includes a step of calculating a difference in the number of rotations of the motor when the number is large, and a step of rotating the motor by reducing the number of windings of the coil when the difference is larger than a predetermined threshold.

[0010] Furthermore, in order to solve the above-mentioned problems, the recording and / or reproducing apparatus for a tape-shaped recording medium according to the present invention is provided with running means for running the tape-shaped recording medium, and recording and / or recording of information signals. A recording / reproducing means for reproducing, a motor capable of driving the traveling means and switching at least two or more windings of a coil through which a driving current flows, and a driving means for driving the motor by switching the number of windings of the motor coil Rotation speed detection means for detecting the rotation speed of the motor based on the cycle of the back electromotive voltage of the coil; and rotation of the motor when the number of windings of the coil is small based on the rotation speed detected by the rotation speed detection means. When the difference between the number of windings with respect to the number of windings and the number of rotations of the motor is larger than a predetermined threshold value, the control means controls the driving means to reduce the number of windings of the coil and rotate the motor. And means.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a tape cassette recording / reproducing apparatus to which the present invention is applied will be described with reference to the drawings.

As shown in FIG. 1, the recording / reproducing apparatus includes:
A tape traveling mechanism 10 which is reduced in size to substantially the same size as the tape cassette 1 and travels the magnetic tape 2; a recording / reproducing unit 20 which amplifies and outputs information signals such as tone signals recorded on the magnetic tape 2; And a motor 30 for driving the mechanism 10. In such a recording / reproducing apparatus, when reproducing an information signal, when the tape cassette 1 is mounted on the main body of the apparatus, the magnetic tape 2 runs at a constant speed by the tape traveling mechanism 10 and the recording / reproducing head 11 transmits the information signal. Reading is performed, and the data is amplified and output by the recording / reproducing unit 20.

The tape running mechanism 10 has a cassette mounting section 1 on which the tape cassette 1 is positioned and mounted.
2 are provided. The cassette mounting portion 12 has a capstan 13 for moving the magnetic tape 2 at a constant speed.
And a pinch roller 14, and reel shafts 15 and 16 for rotating tape reels 3 and 4 around which the magnetic tape 2 of the tape cassette 1 is wound. Such a tape running mechanism 1
When the tape cassette 1 is mounted on the cassette mounting unit 12, the recording / reproducing head 11 enters the tape cassette 1 and comes into contact with the magnetic tape 2. Also, Capstan 1
Numeral 3 holds the magnetic tape 2 together with the pinch roller 14 for running, and the reel shafts 15 and 16 rotate the tape reels 3 and 4 to wind the magnetic tape 2 around the tape reels 3 and 4.

The recording / reproducing section 20 has a recording amplifier 21 for receiving an information signal to be recorded and supplying the information signal to the recording / reproducing head 11, and a preamplifier for receiving an information signal reproduced by the recording / reproducing head 11. 22 and a speaker 23 for outputting the information signal amplified by the preamplifier 22. The recording / reproducing unit 20 includes a recording button, a reproduction button,
An operation unit 24 composed of press operation buttons such as a stop button, a fast forward button, and a rewind button; and a recording for controlling the recording amplifier 21 when recording an information signal or the preamplifier 22 when reproducing an information signal. A reproduction control unit 25.

The operation section 24 supplies an operation signal to the recording / reproduction control section 25 when an operation button constituting the operation section is operated. The operation unit 24 supplies, for example, a recording start signal to the recording / reproduction control unit 25 when the recording button is pressed, and supplies a reproduction start signal to the recording / reproduction control unit 25 when the reproduction button is pressed. I do.

The recording / reproducing control unit 25 supplies a control signal to a motor control unit 50, which will be described later, in order to control the recording amplifier 21, the preamplifier 22, and the like according to an operation signal from the operation unit 24. For example, when a recording start signal is supplied to the recording / reproduction control unit 25, the recording / reproduction control unit 25 supplies a recording control signal to the recording / reproduction head 11, the recording amplifier 21, the motor control unit 50, and the like. When a reproduction start signal is supplied to the recording / reproduction control unit 25, the recording / reproduction control unit 25 supplies a reproduction control signal to the recording / reproduction head 11, the recording amplifier 21, the motor control unit 50, and the like.

When the reproducing button is pressed, the recording / reproducing section 20 amplifies the information signal read from the magnetic tape 2 by the recording / reproducing head 11 by the preamplifier 22 and outputs the signal from the speaker 23. When the recording button is pressed, the recording / reproducing unit 20 amplifies the information signal converted into an electric signal by a microphone, for example, by the recording amplifier 21 and the recording / reproducing head 1
1 is written on the magnetic tape 2.

The motor 30 rotates the capstan 13 when the magnetic tape 2 runs at a constant speed. Specifically, the motor 30 and the capstan 13 are connected via an endless belt to a flywheel for eliminating eccentricity during rotation of the capstan 13 attached to the capstan 13 via an endless belt. The motor 30
Is transmitted to the capstan 13. In addition, the motor 30 is used to wind the magnetic tape 2 when the magnetic tape 2 is run at high speed during recording / reproduction for recording / reproduction, fast-forwarding and rewinding operations. , 16 are rotated. further,
The motor 30 is used only for recording / reproduction.
1 and a pinch roller 14 are moved via a link mechanism from a standby position outside the tape cassette 1 to a recording / reproduction position where it contacts the magnetic tape 2 in the tape cassette 1.

As shown in FIG. 2, the motor 30 is a three-phase DC motor, and includes a stator 31 and a rotor (not shown). The stator 31 includes a coil section 32 including two coils 32a and 32b forming a U phase, a coil section 33 including two coils 33a and 33b forming a V phase, and two coils 3 forming a W phase.
4a and 34b. One ends of the coil units 32, 33, and 34 are commonly connected. Such a stator 31 has one U-phase, V-phase, and W-phase.
The coils 32a, 33a, 34a constituting the phase are arranged at an angular interval of 60 degrees opposite to the other coils 32b, 33b, 34b.

The rotor is constituted by an annular permanent magnet in which S and N poles are alternately magnetized in the circumferential direction.

The U-phase, V-phase, and W-phase coil portions 32, 33,
34 is provided with a first end for switching the direction of the drive current.
Are connected to the connection point between the transistors 35, 36, 37 and the second transistors 38, 39, 40. Here, the first transistors 35, 36, 37 are of the PNP type, and the second transistors 38, 39, 40 are of the NPN type. Then, the first transistors 35, 36, 37
Are connected to the power supply + B of the power supply unit 52. The collectors of the first transistors 35, 36, and 37 are connected to the other ends of the coil units 32, 33, and 34, respectively.
40. On the other hand, the second transistors 38, 3
The collectors 9 and 40 are connected to the other ends of the coil sections 32, 33 and 34, respectively. The emitters of the second transistors 38, 39, 40 are grounded.

The U-phase coil section 32 includes a coil 3
Tap 32c is provided between 2a and coil 32b,
A tap 33c is provided between the coil 33a and the coil 33b in the V-phase coil section 33, and a tap 34c is provided between the coil 34a and the coil 34b in the W-phase coil section 34.
Is provided. The collectors of NPN-type third transistors 41, 42, and 43 are connected to these taps 32c, 33c, and 34c. The emitters of the third transistors 41, 42, 43 are grounded.

Furthermore, U-phase, V-phase and W-phase coil units 3
A common connection point to which one end of each of 2, 33 and 34 is connected is P
The collector of the NP-type fourth transistor 44 is connected. The emitter of the fourth transistor 44 is connected to the power supply + B of the power supply unit 52.

Further, the first to fourth transistors 35
To 44 are connected to the motor control unit 50.

The motor 30 as shown in FIG.
The drive current in both forward and reverse directions is applied to any two of the three-phase, V-phase, and W-phase coil parts 32, 33, and 34, that is, the first electric circuit having a large number of windings and including four coils. The flow mode is the first mode, and the U-phase and V-phase shown in FIG.
Phase and W-phase coil units 32, 33, and 34, one of the coil units and the other one of the coil units, that is, the second electricity having a small number of windings, which is composed of three coils. A mode in which drive currents in both forward and reverse directions flow through the circuit is referred to as a second mode. That is, in the second mode, the number of coils through which the drive current flows is smaller than in the first mode, and a larger amount of the drive current can flow than in the first mode. Therefore, in the second mode, the torque constant is set smaller than the torque constant in the first mode. The timing of switching between the first mode and the second mode will be described later.

A drive circuit for the motor 30 is provided in the recording / reproducing apparatus. As shown in FIG. 1 and FIG. 2, the drive circuit detects a rotation speed of the motor 30 and supplies a rotation speed signal to the motor control unit 50. Rotating speed detector 5
1 and a power supply unit 52 are provided.

The motor control unit 50 performs servo control based on the rotation speed signal and the like supplied from the rotation speed detection unit 51 so that the rotation speed of the motor 30 is constant.
Is supplied to the bases of the first to fourth transistors 35 to 44. Then, the motor control unit 50 switches between the first mode and the second mode. Specifically, the motor control unit 50 determines the rotation speed supplied from the rotation speed detection unit 51 in the first mode from the rotation speed signal supplied from the rotation speed detection unit 51 in the second mode, which will be described in detail later. Subtract a number signal,
Switching between the first mode and the second mode is performed.

The rotational speed detector 51 is connected to a common connection point at one end of the U-phase, V-phase, and W-phase coil units 32, 33, and 34 and the other ends of the coil units 32, 33, and 34, respectively. , V phase,
By detecting the cycle and the phase of the back electromotive voltage of the W-phase coil units 32, 33, and 34, the rotation speed and the rotation phase of the motor 30 are detected. Then, the rotation speed detecting unit 51
A rotation speed signal indicating the detected phase and rotation speed of the motor 30 is supplied to the motor control unit 50.

The power supply section 52 is composed of, for example, a dry battery, a rechargeable battery or the like. Then, the power supply unit 52 supplies electric power to the motor 30 and also supplies electric power to the recording / reproducing head 11, the operation unit 24, the recording / reproducing unit 20, the rotation speed detecting unit 51, the motor control unit 50, and the like.

In such a recording / reproducing apparatus, when the tape cassette 1 is positioned and mounted on the cassette mounting section 12 and the reproduction button is pressed, the operation section 24 supplies an operation signal to the recording / reproduction control section 25. Then, the recording / reproduction control unit 25
Supplies a control signal to the preamplifier 22 and the like in addition to the motor control unit 50. The motor control unit 50 sends a motor control signal to the motor 3 to make the motor 30 run the magnetic tape 2 at a constant speed.
0 to drive the motor 30. Then, the magnetic tape 2 is driven at a constant speed by the capstan 13, the information signal recorded on the magnetic tape 2 is read by the recording / reproducing head 11, amplified by the preamplifier 22, and output from the speaker 23. .

Here, the motor control unit 50 includes a first mode in which drive currents in both forward and reverse directions are supplied to a first electric circuit having a large number of windings, and a second electric mode having a small number of windings, as described below. The first to fourth transistors 35 to 44 are switched so as to perform switching between a second mode in which forward and reverse drive currents flow through the circuit.
Control. The first mode and the second mode are switched when the magnetic tape 2 for recording and reproducing the information signal runs at a constant speed.

The U-phase, V-phase, and W-phase coil portions 32, 33,
In a first mode in which a drive current flows through a first electric circuit composed of any two of the coil portions, ie, a total of four coils, as shown in FIG. 3 and FIG. 42, 43 and the fourth transistor 44 always remain off. Then, in the period t1, the motor control unit 50 controls the first transistor 35 and the second transistor 39 to be simultaneously turned on, and controls the other first to fourth transistors 36 to 38 and 40 to 44 to be turned off. I do. Then, the drive current flows from the U-phase coil section 32 to the V-phase coil section 33.

In the period t2, the motor control unit 50
And the second transistor 40 are simultaneously turned on, and the other first to fourth transistors 36 are turned on.
To 39, 41 to 44 are turned off. Then, the drive current flows from the U-phase coil section 32 to the W-phase coil section 34.

In the period t3, the motor control unit 50
And the second transistor 40 are simultaneously turned on, and the other first to fourth transistors 3 are turned on.
5, 37 to 39, 41 to 44 are turned off. Then, the drive current flows from the V-phase coil unit 33 to the W-phase coil unit 34.

In the period t4, the motor control unit 50
And the second transistor 38 are simultaneously turned on, and the other first to fourth transistors 3
5, 37, 39 to 44 are turned off. Then, the drive current flows from the V-phase coil section 33 to the U-phase coil section 32.

In the period t5, the motor control unit 50
Of the first to fourth transistors 3 and 38 are simultaneously turned on.
5, 36, 39 to 44 are turned off. Then, the drive current flows from the W-phase coil section 34 to the U-phase coil section 32.

In the period t6, the motor control unit 50
The transistor 37 and the second transistor 39 are simultaneously turned on, and the other first through fourth transistors 3 are controlled.
5, 36, 38, and 40 to 44 are turned off. Then, the drive current flows from the W-phase coil section 34 to the V-phase coil section 33. Thereafter, the motor control unit 50 performs the period t1
To t6 are repeated.

The U-phase, V-phase and W-phase coil sections 32, 33,
In the second mode in which a drive current flows through a second electric circuit composed of a total of three coils, one of the coil portions of the coil portion 34 and one of the other one of the coil portions, FIGS. As shown in FIG. 5, the second transistors 38, 39, 4
The zero and fourth transistors 44 always remain off. Then, in the period t1, the motor control unit 50
And the third transistor 42 are simultaneously turned on, and the other first to fourth transistors 36 are turned on.
To 41, 43, and 44 are turned off. Then, the drive current is applied to the coils 32a, 3a constituting the U-phase coil portion 32.
The current flows to the coil 33a constituting the 2b and V-phase coil portions 33.

In the period t2, the motor control unit 50
And the third transistor 43 are simultaneously turned on, and the other first to fourth transistors 36 are turned on.
To 42 and 44 are turned off. Then, the drive current is
The coils 32a and 32b constituting the U-phase coil section 32 and the coils 34a constituting the W-phase coil section 34 flow.

In the period t3, the motor control unit 50
The third transistor 43 and the third transistor 43 are simultaneously turned on, and the other first to fourth transistors 3
5, 37 to 42, 44 are turned off. Then, the drive current is applied to the coils 33a,
33b and a coil 34a constituting the W-phase coil portion 34
Flows to

In the period t4, the motor control unit 50
And the third transistor 41 are simultaneously turned on, and the other first to fourth transistors 3 are turned on.
5, 37 to 40, and 42 to 44 are turned off. Then, the drive current flows through the coils 33a and 33b forming the V-phase coil unit 33 and the coil 32a forming the U-phase coil unit 32.

In the period t5, the motor control unit 50
And the third transistor 41 are simultaneously turned on, and the other first to fourth transistors 3 are turned on.
5, 36, 38 to 40, and 42 to 44 are turned off.
Then, the drive current flows through the coils 34a and 34b forming the W-phase coil portion 34 and the coil 32a forming the U-phase coil portion 32.

In the period t6, the motor control unit 50
And the third transistor 42 are simultaneously turned on, and the other first to fourth transistors 3
5, 36, 38 to 41, 43, and 44 are turned off.
Then, the drive current flows through the coils 34a and 34b forming the W-phase coil unit 34 and the coils 33a forming the V-phase coil unit 33. Thereafter, the motor control unit 50 performs the period t1
To t6 are repeated.

Further, specifically, the motor control unit 50 switches between the first mode and the second mode as shown in FIG.
Perform as shown. First, when the play button or the record button of the operation unit 24 is pressed in step ST1, the motor control unit 50 executes the first to fourth steps in step ST2.
Switches the transistors 35 to 44 to the second mode,
The motor 30 is driven. Then, when the rotation of the motor 30 is stabilized, in step ST3, the rotation number detecting section 51
Detects the rotation speed signal X of the motor 30 in the second mode and supplies the rotation speed signal X to the motor control unit 50.
Here, the motor control unit 50 stores the rotation speed signal X as a predetermined rotation speed signal which is a reference of the motor 30.

Then, the motor control unit 50 determines in step S
At T4, a control signal for switching from the second mode to the first mode is supplied to the first to fourth transistors 35.
To 44 to switch from the second mode to the first mode. In step ST5, when the drive of the motor 30 in the first mode is stabilized, a rotation speed signal Y of the motor 30 in the first mode is detected, and the rotation speed signal Y is supplied to the motor control unit 50. Here, the motor control unit 50 stores the rotation speed signal Y in the first mode.

In step ST6, the motor control unit 50 controls the rotation speed signal X of the motor 30 in the second mode.
Then, the rotation speed signal Y of the motor 30 in the first mode is subtracted, and it is compared whether or not the subtracted value is equal to or greater than a predetermined value A stored in the motor control unit 50 in advance. If the subtraction value is equal to or greater than the predetermined value A, the process proceeds to step ST7. If the subtraction value is less than the predetermined value A, the process proceeds to step ST7.
Returning to 4, the speed signal Y of the motor 30 in the first mode is detected again.

If the subtraction value in step ST6 is equal to or larger than the predetermined value A, in step ST7, the motor control unit 5
0 supplies a control signal to the first to fourth transistors 35 to 44 to switch from the first mode to the second mode. Thereafter, the motor control unit 50 repeatedly performs the operations of steps ST1 to ST7 each time the record button and the play button are pressed.

The case where the motor control unit 500 first detects the rotation speed of the motor 30 in the second mode and then detects the rotation speed of the motor 30 in the first mode has been described. Conversely, the first
The rotation speed of the motor 30 in the second mode may be detected, and then the rotation speed of the motor 30 in the second mode may be detected.

In such a recording / reproducing apparatus, a subtraction value obtained by subtracting the rotation speed signal Y of the motor 30 in the first mode from the rotation speed signal X of the motor 30 in the second mode is a predetermined value A
In other words, when the battery voltage of the power supply unit 52 is high, the motor control unit 50 determines that the number of turns of the first coil is large.
The motor 30 is switched to the mode of
By reducing the drive current flowing through the motors 3 and 34, power can be saved while the rotation speed of the motor 30 is constant. When the battery voltage of the power supply unit 52 decreases, the motor 3
The number of rotations and the torque of 0 become small. When the value obtained by subtracting the rotation speed Y of the motor 30 in the first mode from the rotation speed X of the motor 30 in the second mode is equal to or greater than a predetermined value A, that is, when the battery voltage of the power supply unit 52 is low. The recording / reproducing apparatus switches from the first mode to the second mode, reduces the number of windings of the coil,
By increasing the drive current flowing through the motors 3 and 34, the torque constant can be reduced and the rotation speed of the motor 30 can be kept constant.

That is, in the recording / reproducing apparatus, the motor control unit 50 changes the number of windings of the coil units 32, 33, and 34 based on the number of rotations of the motor 30 detected by the number of rotations detecting unit 51, and By varying the flowing drive current, power saving can be achieved while maintaining the rotation speed of the motor 30 constant without depending on the battery voltage of the power supply unit 52.
In addition, the load on the motor 30 is such that the variation in the torque constant of the motor, the variation in the coil resistance,
The recording / reproducing apparatus has the first mode and the second mode based on the rotation speed of the motor 30, although there is variation due to variations in the on-resistance of the transistor for flowing the drive current through the coil and changes in temperature and aging thereof. Since the mode is switched, without depending on the load of the motor 30,
That is, the interval C shown in FIG. 7 can be reduced, and power can be saved. Therefore, the recording / reproducing apparatus keeps the rotation speed of the capstan 13 for running the magnetic tape 2 and the rotation speed of the reel shafts 15 and 16 for winding the magnetic tape 2 around the tape reels 3 and 4 constant during recording or reproduction. Thus, the running speed of the magnetic tape 2 can be kept constant without depending on the battery voltage, and the recording and reproduction of the information signal can be performed reliably. Further, in the recording / reproducing apparatus, the recording number, the rotation number detecting unit 51 detects the rotation number of the motor 30 each time the reproduction button is pressed,
Since the motor control unit 50 switches the mode, it is possible to optimally control the motor 30 according to the use environment such as the use environment temperature.

Although the recording / reproducing apparatus using the three-phase DC motor has been described above, the present invention is not limited to this, and it is possible to use a larger n-phase motor. In the above description, the motor in which the coil units 32, 33, and 34 are divided into two parts has been described.
2, 33 and 34 may be divided into more m segments.
In such a case, by increasing the number of transistors as the motor driving means, the number of windings of the coil unit can be switched in multiple stages, so that further power saving can be achieved and the magnetic tape 2 can be fast-forwarded. It is also possible to switch between high-speed running, such as rewinding and rewinding, and running at a constant speed of the magnetic tape 2 during recording and reproduction.

[0052]

According to the present invention, the difference between the number of rotations when the number of windings of the coil is large and the number of rotations when the number of windings is large is determined based on the number of rotations detected by the number of rotations detecting means. Since the driving means is controlled so as to rotate the motor by reducing the number of windings of the coil when the value is larger than the threshold value,
It is possible to distinguish whether the decrease in the number of rotations of the motor is due to a decrease in the voltage or the load of the motor, and to accurately switch the number of windings of the motor coil, thereby achieving power saving.
Note that the present invention is particularly effective for portable electronic devices having a limited power supply because power saving is achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a recording / reproducing apparatus to which the present invention has been applied.

FIG. 2 is a circuit diagram for explaining a motor used in the recording / reproducing apparatus.

FIG. 3 is a timing chart showing ON / OFF states of first to fourth transistors.

FIG. 4 is a circuit diagram of a stator for illustrating a current path in a first mode.

FIG. 5 is a circuit diagram of a stator for showing a current path in a second mode.

FIG. 6 is a flowchart showing a procedure for switching between a first mode and a second mode.

[Explanation of symbols]

Reference Signs List 1 tape cassette, 2 magnetic tape, 3, 4 tape reel, 10 tape running mechanism, 11 recording / reproducing head, 12 cassette mounting section, 13 capstan, 14
Pinch roller, 15, 16 reel axis, 20 recording / reproducing unit, 24 operating unit, 25 recording / reproducing control unit, 30 motor, 31 stator, 32 U-phase coil unit, 32a, 3
2b coil, 32c tap, 33 V phase coil part,
33a, 33b coil, 33c tap, 34 W phase coil part, 34a, 34b coil, 34c tap,
35 to 37 first transistor, 38 to 40 second transistor, 41 to 43 third transistor, 44
Fourth transistor, 50 motor control unit, 51 rotation speed detection unit, 52 power supply unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshiyuki Arai 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (3)

[Claims] 1. A motor capable of switching at least two or more windings of a coil through which a driving current flows, a driving means for switching the number of windings of a coil of the motor to drive the motor, Rotation number detecting means for detecting the rotation number of the motor based on the cycle of the voltage; and windings for the rotation number when the number of windings of the coil is small, based on the rotation number detected by the rotation number detecting means. A drive device using a motor, comprising: control means for controlling the drive means so as to rotate the motor by reducing the number of windings of the coil when the difference in the number of rotations when the number is large is larger than a predetermined threshold. . 2. A step of driving a motor capable of switching at least two or more windings of a coil through which a drive current flows; and a step of rotating the motor and a winding of the coil when the number of windings of the coil is small. A step of detecting the number of rotations of the motor when the number of windings is large, and a step of calculating a difference between the number of rotations of the motor when the number of windings is large and the number of rotations of the motor when the number of windings of the coil is small. And a step of rotating the motor by reducing the number of windings of the coil when the difference is greater than a predetermined threshold value. 3. A running means for running a tape-shaped recording medium, a recording / reproducing means for recording and / or reproducing an information signal, and a driving means for driving the running means and having a winding number of at least two coils. A motor that can be switched as described above, a driving unit that drives the motor by switching the number of windings of a coil of the motor, and a rotation speed detection that detects a rotation speed of the motor based on a cycle of a back electromotive voltage of the coil. Means, based on the number of revolutions detected by the number of revolutions detecting means, the difference between the number of turns of the motor when the number of turns of the motor is large and the number of revolutions of the motor when the number of turns is large is predetermined. Control means for controlling the driving means so as to rotate the motor by reducing the number of windings of the coil when the threshold value is larger than the threshold value for recording on a tape-shaped recording medium. Reproducing apparatus.