JPH0260491A - Revolution detector for motor and reel drive controller for tape player using same revolution detector for same motor - Google Patents

Abstract

PURPOSE:To decrease the number of parts by using a magnetic detecting element such as a Hall element installed to a motor and detecting the magnetic pole of a rotor magnet. CONSTITUTION:A flexible board 22 is mounted to a stator yoke 21 in a brushless motor M. A rotor yoke 25 is fixed to a shaft 24, and a rotor magnet 26 is fastened to the rotor yoke 25. Six stator coils 23 and the sight rotor magnets 26 are magnetized. Three magnetic detecting elements 27 are set up on the stator side. A motor driver circuit 31 changes over currents to each stator coil 23 of A-C phase in response to magnetic detecting signals from the three Hall clements 27. A revolution detector 32 measures the number of revolution on the basis of said magnetic detecting signals, and is composed of waveform shaping circuits 33 and a counter circuit 34, and the number of revolution of the motor M can be determined. Accordingly, the number of revolution can be controlled at a constant value.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a motor rotation detection device that is capable of detecting the rotation speed of a brushless motor or the like without the need for a special detector, and to the rotation detection device. The present invention relates to a reel drive control device in a tape player that is used to control tape running.

[Prior Art] FIG. 10 shows a reel drive control device for a rotary head type tape player used in a conventional DAT (Digital Audio Recorder) or the like.

In the figure, reference numeral 1 denotes a supply reel stand on which a supply tape reel R1 is installed, and reference numeral 2 represents a take-up reel stand on which a take-up tape reel R2 is installed. Reference numeral 3 is a rotating head drum. The magnetic tape T wound on both tape reels R1 and R2 is pulled out by a tape loading mechanism and wound around the rotary head drum 3. code 4a
and 4b are lobe posts for pulling out the mqi tape T. Also, during recording or reproduction, the magnetic tape T is held between a capstan 5 rotating at a constant speed and a pinch roller 6 pressed against the capstan 5, and wound up according to the number of rotations of the capstan 5. It is made to run in the direction of the side reel stand 2.

The supply reel stand 1 is driven by a supply reel motor M1, and the take-up reel stand 2 is driven by a take-up reel motor M2. As shown in FIG. 11, the supply side reel motor M1 is constituted by a brushless motor comprising a stator coil 7 and a rotor magnet 6, and the take-up side reel motor M2 is similarly constituted by a brushless motor.

A rotation speed detection button 9a is formed at the base end of the supply side reel stand 1, and an optical detector 10a faces this rotation speed detection button 9a. Similarly, a rotation detection pattern 9b is formed at the base end of the take-up reel stand 2, and an optical detector 10b faces this. Rotation speed detection pattern 9
9a and 9b are optical detectors 9a and 9b in which reflecting parts and non-reflecting parts are alternately formed along the rotation direction.
Alternatively, the rotational speed of the reel stands 1 and 2 can be detected by detecting the reflected light by the reel 9b. Various controls are performed by detecting the rotational speed of the reel stands 1 and 2. For example, during high-speed search operation, the rotational speed of both reel stands 1 and 2 is counted by the rotational speed counting circuit 11, and the reel motor is driven. The control circuit 11 calculates the difference. Furthermore, the running speed of the magnetic tape T at that point is calculated by the reel motor drive control circuit 12,
The rotation of both reel motors M1 and M2 is controlled in accordance with this calculated value, so that the tape running speed is always kept constant.

[Problem to be solved by the invention]

As described above, conventionally, rotation speed detection patterns 9a and 9b are formed at the bases of reel stands 1 and 2 as a mechanism for detecting the rotation speed of reel stands 1 and 2, that is, reel motors M1 and M2. , and optical detectors 10a and 10b facing each pattern are also provided. Therefore, the mechanism for detecting the reel rotation speed has become complicated, and the number of parts has also increased.

The present invention solves the above-mentioned problems, and provides a motor rotation detection device and a motor rotation detection device that can detect the number of rotations using the functions of the motor without using a special detection device. The object of the present invention is to provide a reel drive control device for a tape player using the following.

[Means to solve the problem]

The rotation detection device according to the present invention includes a plurality of stator coils and rotor magnets that rotate opposite to the stator coils and have different magnetic poles alternately provided in the rotation direction. In a motor equipped with a magnetic detection element for detecting the switching signal for supplying current to the stator coil, the detection signal of the magnetic pole of the rotor magnet obtained by the magnetic detection element is counted and the detection signal of the magnetic pole of the rotor magnet is detected. It is characterized by being provided with a counting circuit that calculates the number of rotations.

Furthermore, the motor rotation detecting device according to the present invention provides a motor including a plurality of stator coils and a rotor magnet that rotates opposite to the stator coils and has different magnetic poles alternately provided in the rotational direction. A counter that detects the electromotive force generated by the passage of the magnetic pole of the rotor magnet 1- in a coil in which the motor drive current is not flowing at a certain point among the stator coils of the stator coil, and calculates the rotation speed of the rotor magnet by counting this detection signal. It is characterized by being provided with a circuit.

Further, the reel drive control device according to the present invention includes a take-up reel motor that drives a take-up tape reel, a supply reel motor that drives a supply tape reel, and a magnetic head that contacts the magnetic tape between both tape reels. In the table roller, the take-up reel motor is equipped with
A rotation detection device using the signal from the above magnetic sensing element is connected, and the rotation detection device using the above coil electromotive force is connected to the supply reel motor. A control circuit is provided that compares the motor rotation speed detected from the take-up reel motor with the motor rotation speed detected from the take-up reel motor and supplies a drive signal to each motor so as to control the tape running speed. It is something to do.

[Function] The motor rotation detection device according to the present invention detects a magnetic pole detection signal from a magnetic sensing element, which serves as a reference signal for switching the supply of current to the stator coil, or a magnetic pole detection signal caused by an electromotive force generated in the stator coil. The rotation speed of the motor is detected by counting. Since all of these signals are output in response to changes in the magnetic poles of the rotor magnet, the rotation speed of the rotor magnet can be reliably detected using these detection signals. Therefore, it is not necessary to provide a detection vacuum or an optical detector as in the prior art, and the rotational speed of the rotor can be detected with an extremely simple structure.

Furthermore, in the reel drive control device for a tape player according to the present invention, a rotation detection device using a magnetic sensing element is used for the take-up reel motor, and a rotation detection device using electromotive force of a coil is used for the supply reel motor. ing. A rotation detection device using a magnetic sensing element can detect rotation speed not only at high speed rotation but also at low speed rotation. Furthermore, a rotation detection device that uses the electromotive force of a coil can exhibit detection accuracy in the case of high-speed rotation.

Therefore, in the case of a high-speed search, the reel drive control device of this tape player uses the detected rotational speed value of the supply side reel motor and the rotational speed detection value of the take-up side reel motor to determine the rotational speed of both reels at that time. The difference can be detected, and various motor rotational speeds can be controlled depending on the difference, such as keeping the tape running speed constant. In addition, when the tape runs at low speeds such as during recording and playback, the rotation speed of the take-up reel motor using a magnetic sensing element is used to detect
You can know the reel rotation speed.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings of FIGS. 1 to 9.

1 to 7 show a first embodiment of the present invention, and show a motor rotation detection device using a magnetic detection element.

Figure 1 is a sectional view showing the structure of brushless motor M, Figure 2 is a cross-sectional view showing the structure of brushless motor M.
The figure is a plan view showing the stake portion, and FIG. 3 is a plan view showing the surface of the rotor magnet facing the stator.

In this brushless motor M, a flexible substrate 22 is attached to a stator yoke 21, and a plurality of stator coils 23 are installed on the flexible substrate 22.

A loaf yoke 25 is fixed to the rotating shaft 24, and rotor magnets 1 to 26 are fixed to this loaf yoke. This brushless motor M is an 8-pole 6-coil motor, and has six stator coils 23 as shown in FIG. 2, and a rotor magnet 1 as shown in FIG.
26, among the 66 stator coils 23 which are magnetized with 8 N poles and S poles alternately in the rotation direction, those indicated by Al and A2 are the A phase, and current is applied to both at the same time. Supplied. Also, what is not shown by B1 and B2 is B phase, and C
1 and C2 are the C phase. Additionally, as shown in Figure 2, there are three magnetic sensing elements (Hall elements) on the stator side.
27 are provided. These three ball elements 27 are
One of them corresponds to each of the A-phase, B-phase, and C-phase stator coils, and the supply of current to each stator coil is switched in accordance with the change in the magnetic pole detected by each Hall element 27.

FIG. 4 shows a motor drive circuit 31 that drives the motor shown in FIGS. 1 to 3, as well as a rotation speed detection device that is a feature of the present invention.

In the motor drive circuit 31, currents to the A-phase, B-phase, and C-phase stator coils 23 are switched in response to magnetic pole detection signals from the three Hall elements 27.

In addition, in FIG. 4, both coils A1 and A2 connected in series are schematically shown as one A-phase coil. The same applies to the B-phase and C-phase coils. Although there are various circuit configurations of the motor drive circuit 31,
FIG. 5 shows an example of a three-phase drive circuit using three Hall elements 27. The blocks surrounded by dotted lines in FIG. 5 are, for example, each of the C-phase stator coils 2.
7 (C1 and C2).

In the case of a two-phase motor, there are two other similar block configurations corresponding to the A phase and B phase. In one block, when one Hall element 27 detects a change in the magnetic pole of the rotor magnet passing over it, the detection signal causes transistors Tri and Tr2 to be connected to each other.
operates, and its switching operation causes the C phase (CI
A current is supplied to the stator coil 27 (of C2 and C2). Similarly, the supply of current to the B-phase and C-phase stator coils is switched in accordance with the magnetic detection signals from the respective Hall elements. This switching of current supply to the coils of each phase is performed in order.

FIG. 7 conceptually shows the principle by which the rotor magnet 26 is driven to rotate in accordance with the supply of current to the stator coil 23 of each phase. For convenience of explanation, 0-ta magnet 26
Each magnetic pole and the stator coil 23 are shown extending horizontally.

Further, the advancing direction (rotation direction) of the rotor magnet 26 is
Direction to the left of the figure. First, in stage (I), current is supplied to the A-phase stator coils A1 and A2, and due to their relationship with the magnetic poles of the rotor magnet 26 facing each other (according to Fleming's left-hand rule), the rotor A driving force acts on the magnet in the left direction in the figure. When the rotor magnet 26 advances to the stage (II), current is supplied to the C-phase stator coils C1 and C2 by the switching operation of the motor drive circuit 31 shown in FIG. ), current is supplied to the B-phase stator coils B1 and B2.

Further, at the stage (IV), current is again supplied to the A-phase stator coil. However, in the stage 1v) and the stage (I), the magnetic poles of the magnet facing the A-phase stator coil are opposite, so the directions of current supply to the A1 and A2 coils are opposite. Motor drive circuit 3
1, the rotor magnet 26 is continuously driven to rotate.

Further, in the rotation detecting device 32 of the present invention shown in FIG. 4, the number of rotations is measured based on the magnetic pole detection signal from the Hall element 27. This rotation speed detection circuit 32 is composed of, for example, a waveform shaping circuit 33 and a counting circuit 34, but it is possible to provide these circuits in the same IC as the motor drive circuit 31, or to detect the rotation speed. circuit 32
The same function can also be performed by the CPU of a microcomputer. As described above, the three Hall elements 27 output magnetic pole detection signals in response to passage of the magnetic poles of the rotor magnet 26.

One Hall element 27 can obtain eight magnetic pole detection signals per one rotation of the rotor magnet 26 having an eight-pole configuration. Therefore, from the three Hall elements 27, the rotor magnet 2
A total of 24 detection signals are obtained per rotation of 6. In FIG. 4, if the three ball elements 27 are respectively (a) (bl[C), the magnetic pole detection signal detected by each Hall element 27 is shaped by the waveform shaping circuit 33, and as shown in FIG. After a certain period of time, a waveform of [a) (b) (cl) is obtained. By adding the waveforms of (a) (1]) (c) in the counting circuit 34, the waveform shown in (d) is obtained. A pulse signal with a constant time pitch is obtained.As described above, 24 pulses shown in (d) are obtained per one rotation of the rotor magnet 26.For example, in the counting circuit 34, the number of pulses shown in [d] is obtained. By counting the number of rotations within a certain period of time, it becomes possible to know the number of rotations of the brushless motor M. This counted value can be used in various ways; for example, by displaying this counted value on a display device, the number of rotations of the motor can be immediately known. Moreover, this count value can also be used as various control data. For example, the current rotation speed of the motor M can be determined based on this data, and if the switching of the motor drive current is controlled based on this data, it becomes possible to control the rotation speed to be constant.

FIG. 8 shows a second embodiment of the present invention,
This embodiment does not use the Hall element described above, but instead uses the electromotive force generated in the stator coil as a detection signal for the magnetic pole of the rotor magnet. Figure 8 is A
The wiring state of each stator coil 23 of phase, B phase, and C phase is shown.

Also, in this figure, the magnetic poles of the stator coil 23 and the rotor magnet 26 are shown in a horizontally developed state, similar to FIG. 7.

In FIG. 8, for example, common terminal Do and C phase (CI and C
A current ■ is supplied between the coil terminals Co of the stator coils C1 and 02 connected in series, and at a certain point the stator coils C1 and 02
When a clockwise current is supplied to the rotor magnet 26, this current and the magnetic poles of the rotor magnet 26 exert a driving force on the rotor magnet 26 in the direction of the arrow. At this point, in the A-phase or B-phase coil where the motor drive current ■ is not flowing, an electromotive force is generated according to the movement of the magnetic poles of the rotor magnet (in this case, Fleming's right-hand rule), A
A current 1 due to electromotive force is obtained in the phase coil or the B-phase coil. FIG. 8 shows a case where a current 1 due to an electromotive force flows through the B-phase coil terminal Co. If this current 1 is taken out at the right time and, for example, a current above a certain level or an electromotive force above a certain voltage is generated, the waveform of this current 1 is shaped into a signal from the Hall element as shown in Fig. 6. A similar magnetic sensing signal is obtained. By performing a switching operation for supplying current to the coils of each phase in response to this magnetic detection signal, it is possible to perform the same function as a Hall element. In the present invention,
The rotational speed is detected using a signal generated by the electromotive force of this coil. This electromotive force is a signal corresponding to the number of changes in the magnetic pole of the rotating rotor magnet, so by detecting this signal and counting it with a counter circuit 34 equivalent to that shown in FIG. It becomes possible to know the rotation speed of the rotor magnet 26.

Next, FIG. 9 shows a third embodiment of the present invention, and shows a reel drive control device in a rotary head type tape player using the motor rotation detection device in each of the above embodiments.

In FIG. 9, reference numeral 1 denotes a supply reel stand, on which a supply tape reel R1 is installed. Reference numeral 2 denotes a take-up reel stand, on which a take-up tape reel R2 is installed. The magnetic tape T wound on each tape reel R1 and R2 is pulled out by loading posts 4a and 4b of a tape loading mechanism and wound around the rotating head drum 3. Further, numeral 5 is a capstan, and 6 is a pinch roller that presses the magnetic tape T against the capstan.

The supply reel stand 1 is driven by a supply reel motor Ma, and the take-up reel stand 2 is driven by a take-up reel motor Mb. The take-up side reel motor Mb is shown in Figure 1~
The rotation detection device according to the first embodiment shown in FIG. 7 is used. That is, in the winding-side reel motor Mb, the magnetic pole detection signal S2 of the rotor magnet 26 detected by the Hall element 27 is obtained. Further, in the supply side reel motor Ma, a rotation detection device according to the second embodiment shown in FIG. 8 is used. That is, in the supply side reel motor Ma, the magnetic pole detection signal S1 of the rotor magnet 26 is obtained by the electromotive force generated in the stator coil of the phase in which the motor drive current is not flowing at a certain point in time. The rotation speed detection circuit 41 to which both the detection signals Sl and 82 are inputted is obtained from a plurality of Hall elements provided on the winding side reel motor Mb, similar to the rotation speed detection circuit 32 shown in FIG. The detection signal S2 is waveform-shaped to obtain a pulse signal as shown in FIG. 6(d). At the same time, the rotation speed detection circuit 4
1, a pulse signal corresponding to the rotation speed of the supply reel stand 1 is formed based on the magnetic pole detection signal Sl obtained from the electromotive force generated in the coil by the supply reel motor Ma. The reel motor control circuit 42 compares the motor rotational speeds calculated based on the magnetic pole detection signals S1 and 32 from the respective motors Ma and Mb, and determines the difference in the rotational speed at that point in time between the two reel motors Ma and Mb. is calculated. Further, the reel motor drive control circuit 42 calculates the motor rotation speed for keeping the tape running speed constant according to the difference in the rotation speed of both mokes, and based on the result, the motor drive as shown in FIG. The circuit is controlled and each motor IVT
Motor drive signals Sa and sb are now given to a and Mb.

In the above rotation detection device, the take-up side reel motor Mb
In this case, since the rotational speed is measured based on the signal from the Hall element, the detection operation is possible whether the rotation is high speed or low speed rotation. On the other hand, in the supply side Lilmork IVI a, since the magnetic pole detection signal S1 is obtained by the electromotive force of the coil, it is difficult to obtain a signal from the electromotive force unless the rotation speed of the motor is high to a certain extent. Therefore, the actual control operation is performed as follows using the characteristics of the rotation detection devices of both motors.

In the high-speed search operation, the rotation speed of the supply side reel motor Ma increases. Therefore, it is possible to accurately extract the detection signal Sl of the magnetic pole due to the electromotive force. That is, in the search operation in tape fast forwarding (FF), the take-up reel motor Mb is driven and the supply reel motor Ma is not driven, but the magnetic pole detection signal St is obtained by the electromotive force generated in the stator coil of the supply reel motor Ma. It is possible. Furthermore, in the search operation during tape rewinding (REW), the supply reel motor Ma is driven at high speed, so it is possible to obtain the magnetic pole detection signal S1 by the electromotive force of the stator coil through which no drive current is flowing.

Incidentally, in the unwinding operation during rewinding (REW), the reel motor Mb on the winding side is not driven, but is kept in a state in which only the detection operation by the Hall element can be performed. In this way, in both fast forward and rewind search operations, each motor Ma and M
The rotational speed of both motors and the difference between the rotational speeds are detected from the magnetic pole detection signals Sl and 82 taken out from Drive control is performed.

Next, in recording or reproducing operation, the take-up reel motor Mb
The tape is wound at low speed. At this time, in the supply reel motor Ma, it is difficult to extract the electromotive force from the coil, making it difficult to obtain the magnetic pole detection signal S1.

However, in the winding side reel motor Mb, since the magnetic pole detection signal S2 is obtained from the Hall element, this signal S2
is used to control the drive of the take-up reel motor Mb, the drive of the capstan 5, or the rotating head drum 3.
Along with the rotation speed information, various controls such as read timing control are possible.

In addition, in the example shown in the figure, a brushless motor on the horizontally opposing side as shown in FIG. The same method can be applied even in the case of a opposed brushless motor.

Further, in a tape player, various controls are possible by not only controlling the tape running speed to be constant but also by knowing the number of revolutions of each reel stand. Further, the tape player is not limited to a rotary head type, and even a fixed head type tape player can similarly perform tape running control.

[Effects of the Invention] As described above, the motor rotation detection device according to the present invention uses a magnetic detection element such as a Hall element provided in the motor, or uses the electromotive force of the stator coil to detect the rotation of the rotor magnet. Because the magnetic pole is detected,
The number of rotations can be detected without using a detection pattern or an optical detector as shown in FIGS. 10 and 11. Therefore, the number of parts for motor control can be significantly reduced compared to the conventional method. In particular, in the invention according to claim 2, since no ball element is used, it is possible to detect the rotation speed of the motor using only the minimum number of motor parts without providing any detection element.

Furthermore, the reel drive control device for a tape player according to the present invention enables reel drive control in both high-speed search operations and recording/reproducing operations without providing any special detection device. In particular, since the AT magnetic sensing element is used only in the reel motor on the take-up side, and there is no need to provide a magnetic sensing element on the reel motor on the supply side, the drive unit of the tape player can be realized with a minimum number of parts. .

[Brief explanation of the drawing]

1 to 7 show a first embodiment of the present invention, and show a motor rotation detection device using a magnetic detection element. Figure 1 is a sectional view showing the structure of a brushless motor, Figure 2 is a plan view of the stake side, Figure 3 is a plan view showing the surface of the rotor magnet facing the stator, and Figure 4 is based on signals from the magnetic sensing element. FIG. 5 is a circuit diagram showing an example of a motor drive circuit, FIG. 6 is a diagram showing a magnetic pole detection signal obtained from a magnetic detection element, and FIG. 7 is a circuit diagram showing a motor drive circuit and a rotation speed detection circuit. FIG. 3 is an explanatory diagram schematically showing a current switching operation for each stator coil of the brushless motor. FIG. 8 shows a second embodiment of the present invention, and is a schematic diagram showing the wiring state of the stator coil of a motor used in a rotation detection device that obtains a magnetic pole detection signal using the electromotive force of the coil. FIG. 9 shows a third embodiment of the present invention, and FIG. 10 is a plan view showing a reel drive control device for a rotary head tape player, and FIG. 10 is a plan view showing a reel drive control device for a conventional rotary head tape player. figure,
FIG. 11 is a perspective view showing the structure of a conventional rotation speed detection mechanism. 1... Supply side reel stand, 2... Take-up side reel stand, 3
...Rotating head drum, 5 cabbage, 6...pinch roller, R1...supply side tape reel, R2...
Take-up side tape reel, M... Brushless motor, Ma...
... Supply side reel motor, Mb... Winding side reel motor, 23... Stator coil, 26... Rotor magnet, 32... Rotation speed detection circuit, 41... Rotation speed detection circuit, 42. ...Reel motor drive control circuit. Applicant Alps Electric Co., Ltd.

Claims (1)

[Claims] 1. Consisting of a plurality of stator coils and a rotor magnet that rotates opposite to the stator coil and has different magnetic poles alternately provided in the rotation direction, and the magnetic poles of the rotor magnet are on the stator side. In a motor equipped with a magnetic detection element for detecting the switching signal for supplying current to the stator coil, the detection signal of the magnetic pole of the rotor magnet obtained by the magnetic detection element is counted and the detection signal of the magnetic pole of the rotor magnet is detected. A rotation detecting device 2 characterized by being provided with a counting circuit for calculating the number of rotations, a plurality of stator coils, rotating opposite to the stator coils, and having different magnetic poles alternately provided in the direction of rotation. In a motor consisting of a rotor magnet,
The electromotive force generated by the passage of the magnetic poles of the rotor magnet is detected in a coil to which a motor drive current is not flowing at a certain point among the plurality of stator coils, and the rotation speed of the rotor magnet is calculated by counting this detection signal. The rotation detection device 3 is characterized by being provided with a counting circuit, a take-up reel motor that drives the take-up tape reel, a supply reel motor that drives the supply tape reel, and In a tape player provided with a magnetic head that contacts the magnetic tape, the rotation detection device according to claim 1 is connected to the take-up side reel motor, and the rotation detection device according to claim 2 is connected to the supply side reel motor. is connected, and a drive signal is sent to each motor so that the tape running speed can be controlled by comparing the motor rotation speed detected from the supply side reel motor and the motor rotation speed detected from the take-up side reel motor. A reel drive control device characterized by being provided with a control circuit that supplies