JP2007159273A - Pulse motor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To normally rotate or reverse the rotor of a pulse motor. <P>SOLUTION: A magnetic sensor 3 is arranged near the rotor 1 of the pulse motor 11 so as to detect the rotational direction of the rotor 1. Stator magnetic poles 2p and 2q are made so that the angle θ between a dynamic magnetic center line L2 and a static stability line L1 may be not less than 45° and not more than 90° in the direction of normal rotation. A control circuit for driving this pulse motor 11 judges the direction of the rotor 1, based on the detection signal of the magnetic sensor 3, and judges the rotational direction of the rotor 1, based on a rotational direction switching signal. Then, the control circuit generates a drive pulse signal so as to rotate the rotor 1, based on the direction of the rotor 1 and the rotational direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a pulse motor device.

  As a timepiece motor, there is a single-phase two-pole pulse motor device capable of forward and reverse rotation (see, for example, Patent Document 1).

  In this pulse motor device, the static stable position of the rotor in the non-excited state is at a position displaced by approximately 90 degrees with respect to the dynamic magnetic center of the stator magnetic pole in the excited state. A single polarity initialization pulse having a width is generated. Thereafter, the pulse motor device outputs a normally driven pulse to the pulse motor and drives it in a desired rotation direction.

Japanese Patent No. 2614769

  However, the conventional pulse motor device outputs a pulse having a large pulse width in order to fix the phase of the rotor at the initial operation. However, if the rotor rotates 180 ° for some reason after that, or if a feed error is made once with a normal pulse, there is a problem that the motor reverses thereafter. In order to prevent this, if a pulse having a large pulse width is output each time before a normal pulse is output, there is a problem that current consumption increases.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a pulse motor device that can reliably rotate forward or reverse.

In order to achieve this object, a pulse motor device according to the first aspect of the present invention provides:
A rotor in which N and S poles are magnetized in two poles;
A stator comprising a pair of stator magnetic poles for driving the rotor and having a hole through which the rotor passes;
A drive coil for exciting the stator;
A magnetic sensor that is arranged near the shaft surface of the rotor, detects a magnetic pole of the rotor adjacent thereto, and outputs a detection signal;
A control unit that determines the orientation of the rotor based on a detection signal output from the magnetic sensor, and that controls energization to the drive coil based on the determined orientation of the rotor and the instructed rotation direction; It is characterized by having.

  The controller determines the orientation of the rotor based on a detection signal output from the magnetic sensor, and generates a drive pulse signal based on the determined orientation of the rotor and an instructed rotation direction. Then, before generating the drive pulse signal, the orientation of the rotor may be determined based on the detection signal output from the magnetic sensor.

In the stator, the angle of the static stability line indicating the direction in which the rotor is stationary in a non-excited state with respect to the dynamic magnetic center line of the stator magnetic pole is 45 ° or more and 90 ° or less in the forward rotation direction. The pair of stator magnetic poles is formed on
The magnetic sensor may be arranged in the vicinity of a position shifted by 90 ° with respect to the dynamic magnetic center line.

  According to the present invention, the direction of rotation can be specified with certainty.

Hereinafter, a pulse motor device according to an embodiment of the present invention will be described with reference to the drawings.
The pulse motor device according to this embodiment includes a pulse motor and a pulse motor drive circuit. The configuration of the pulse motor is shown in FIG.
As shown in FIG. 1, the pulse motor 11 includes a rotor 1, a stator 2, a magnetic sensor 3, a coil core 5, and a drive coil 6.

  The rotor 1 is constituted by a disk-shaped permanent magnet, and both ends of the diameter of the rotor 1 are magnetized to two poles of N pole and S pole, respectively.

  The stator 2 is formed by integrating stator magnetic poles 2p and 2q, and a circular hole 2a for inserting the rotor 1 is provided at the center.

  Narrows 2b and 2c are provided on the upper and lower sides of the stator 2 on the straight line Y, where Y is a straight line extending in the vertical direction through the center of the circular hole 2a. The cross-sectional area of the stator 2 is reduced at the narrow portions 2b and 2c, and the magnetic resistance is increased. Accordingly, the stator 2 is magnetically divided into left and right with the straight line Y as a boundary.

  A coil core 5 is provided at the lower end of the stator 2, and a drive coil 6 is wound around the coil core 5. Input terminals 6 a and 6 b are provided at both ends of the drive coil 6. A magnetic circuit is formed with a straight line extending through the center of the circular hole 2a as a dynamic magnetic center line L2. The pair of stator magnetic poles 2p and 2q are formed on both sides of the circular hole 2a on the dynamic magnetic center line L2.

  When a drive pulse is applied to the drive coil 6 via the input terminals 6a and 6b, the stator magnetic poles 2p and 2q are excited to be N poles or S poles via the coil core 5.

  The circular hole 2a is provided with a pair of arc-shaped notches 2d and 2e. The notches 2d and 2e are provided on the notch center line L3.

  The notches 2d and 2e have a shape symmetrical with respect to the notch center line L3. For this reason, when the stator 2 is in a non-excited state, the N pole and S pole of the rotor 1 are located at equal distances from the two notches, and the rotor 1 is stationary in this state.

  That is, the rotor 1 stands still in a state where the straight line connecting the N pole and S pole of the rotor 1 and the static stability line L1 coincide. The static stable line L1 is a line indicating the direction in which the rotor 1 is stationary in the non-excited state, and the position of the static stable line L1 is the static stable position.

  The angle formed by the static stability line L1 and the notch center line L3 is 90 °. The stator magnetic poles 2p and 2q are formed such that the angle θ is 45 ° or more and 90 ° or less in the forward rotation direction, where θ is the angle of the static stability line L1 with respect to the dynamic magnetic center line L2. The fact that the angle θ is approximately 90 ° is effective for reducing the difference in characteristics between forward rotation and reverse rotation.

  In addition, the angle θ formed by the dynamic magnetic center line L2 and the static stability line L1 may be set to approximately 45 °, whereby the most efficient motor can be obtained in the case of normal rotation. In this case, in order to reverse, it is necessary to input a drive pulse with higher energy (specifically, a pulse having a long pulse width or a combination of two or more kinds of pulses having different polarities).

  However, in the case of a watch, in general, since the motor is normally rotated for most of the time, setting the angle θ to approximately 45 ° is effective for obtaining a highly efficient watch having a long battery life. It is also effective in preventing reverse rotation during normal times. Further, the angle θ formed by the dynamic magnetic center line L2 and the static stability line L1 may be determined within a range of 45 ° or more and 90 ° or less, taking into account the respective advantages.

  The magnetic sensor 3 detects the strength of the magnetic field to be measured, and is disposed in the vicinity of the rotor 1 as shown in FIG. As the magnetic sensor 3, a semiconductor magnetoresistive element, Hall element, ferromagnetic thin film element, coil pickup, or the like is used.

  The magnetic sensor 3 is disposed in the vicinity of a position shifted by 90 ° with respect to the dynamic center line L2, that is, a position shifted by 90 ° and an error range set in advance around this position. For this reason, the position of the magnetic sensor 3 is shifted by 0 to 45 ° with respect to the pole of the rotor 1 located at the static stable position, and the magnetic sensor 3 determines the direction when the rotor 1 is stationary. To obtain the strength of the magnetic field required to

  At the same time, if the magnetic sensor 3 is disposed in the vicinity of a position shifted by 90 ° with respect to the dynamic center line L2, the timing of switching the polarity of the drive pulse signal during non-intermittent high-speed rotation of the pulse motor 11 described later. And the timing at which the signal of the magnetic sensor 3 crosses zero. For this reason, when the magnetic sensor 3 is also used for drive pulse control during high-speed rotation, control of the drive pulse signal during high-speed rotation is facilitated.

  The magnetic sensor 3 of the present embodiment outputs an L_HIGH detection signal when approaching the N pole of the rotor 1, and outputs an L_LOW detection signal when approaching the S pole of the rotor 1.

The motor drive circuit shown in FIG. 2 drives the pulse motor 11.
The motor drive circuit includes a crystal oscillator 12, a frequency divider 13, a control circuit 14, a driver 15, a forward / reverse selector switch 16, and a magnetic sensor 3.

The crystal oscillator 12 outputs a signal having a constant frequency.
The frequency divider 13 divides the frequency of the signal output from the crystal oscillator 12.

  The forward / reverse selector switch 16 is a switch for switching forward / reverse rotation of the pulse motor 11 manually by supplying a rotation direction switching signal to the control circuit 14. The magnetic sensor 3 described above supplies a detection signal to the control circuit 14.

  The control circuit 14 supplies drive pulse signals O1 and O2 to the driver 15. The control circuit 14 includes a CPU, a ROM, a RAM, and the like (not shown), and determines the rotational direction of the rotor 1 based on the rotational direction switching signal supplied from the forward / reverse selector switch 16. Further, the control circuit 14 supplies drive pulse signals O1 and O2 to the driver 15 based on the detection signal supplied from the magnetic sensor 3.

  The driver 15 amplifies the drive pulse signals O1 and O2 supplied from the control circuit 14, and supplies the drive pulse signals OUT1 and OUT2 to the pulse motor 11. In this embodiment, when the drive pulse signal OUT1 is supplied to the input terminal 6a and the drive pulse signal OUT2 is supplied to the input terminal 6b, and the drive pulse signal O1 = LOW and O2 = HIGH, the driver 15 uses the drive pulse signal OUT1. = LOW, OUT2 = HIGH, and a driving current is supplied to the pulse motor 11 so that the stator magnetic pole 2p is magnetized to the N pole and the stator magnetic pole 2q is magnetized to the S pole.

Next, the operation of the pulse motor device according to the embodiment will be described.
The pulse motor device normally drives the pulse motor 11 with intermittent rotation at regular intervals at predetermined intervals, and when correcting the display of the timepiece, the interval is shorter than normal or non-intermittent rotation, or a manual switch (not shown) is used. The pulse motor 11 is rotated forward or backward in accordance with the input signal.

  The crystal oscillator 12 outputs a signal having a constant frequency to the frequency divider 13, and the frequency divider 13 outputs the frequency-divided signal to the control circuit 14.

  The control circuit 14 executes the drive control process (1) according to the flowchart shown in FIG. 3, and supplies the drive pulse signals O1 and O2 having a predetermined width to the driver 15 at every timing of the pointer movement

  The control circuit 14 determines the orientation of the rotor 1 based on the detection signal of the magnetic sensor 3 (step S11).

  If it is determined in step S11 that the polarity is N, the control circuit 14 determines whether the direction of rotation is normal or reverse based on the rotation direction switching signal supplied from the forward / reverse selector switch 16 (step S12). If it is determined in step S12 that the rotation direction is the normal rotation direction, the control circuit 14 sets the output drive pulse signal O1 = LOW and O2 = HIGH (step S13).

  If it is determined in step S12 that the rotation is reverse, the control circuit 14 sets the drive pulse signal to be output to O1 = HIGH and O2 = LOW (step S14).

  If it is determined in step S11 that it is the S pole, the control circuit 14 determines whether the rotation direction is the forward rotation direction or the reverse rotation direction based on the rotation direction switching signal supplied from the forward / reverse selector switch 16 (step 15).

  If it is determined in step S15 that the rotation direction is the normal rotation direction, the control circuit 14 sets the output drive pulse signal OUT to O1 = HIGH and OUT2 = LOW (step S16).

  If it is determined in step S15 that the rotation direction is the reverse rotation direction, the control circuit 14 sets the output drive pulse signal to O1 = LOW and O2 = HIGH (step S17).

Next, a specific operation of the pulse motor device will be described.
As shown in FIG. 4A, when the rotor 1 is stopped at the position indicated by Pos11, the signal level of the detection signal of the magnetic sensor 3 is L_HIGH as shown in FIG. 4B.

  Based on the signal level L_HIGH, the control circuit 14 determines that the magnetic sensor 3 is close to the north pole of the rotor 1 (“L_HIGH” in step S11).

  If the rotation direction switching signal supplied from the forward / reverse selector switch 16 indicates normal rotation, the control circuit 14 drives the drive pulse signal O1 = LOW, O2 as shown in FIGS. 4 (c) and 4 (d). = HIGH is output (processing of step S13).

  The driver 15 amplifies the drive pulse signals O1 and O2, outputs a drive pulse signal of OUT1 = LOW, OUT2 = HIGH, and supplies a drive current to the drive coil 6. When a drive current flows through the drive coil 6, the stator magnetic pole 2p is magnetized to the N pole and the stator magnetic pole 2q is magnetized to the S pole.

  As the stator magnetic poles 2p and 2q are magnetized in this way, the rotor 1 rotates forward in the positive direction indicated by the arrow in FIG. As shown in FIGS. 4C and 4D, the control circuit 14 raises the drive pulse signal O1 and lowers the drive pulse signal O2 after a predetermined time has elapsed, and the magnetism of the stator magnetic poles 2p and 2q disappears. To do. However, the rotor 1 rotates forward as it is due to inertia and stops at the position indicated by Pos13 via the position indicated by Pos12.

  When the rotor 1 rotates and stops at the position indicated by Pos13 shown in FIG. 4A, the signal level of the detection signal of the magnetic sensor 3 is L_LOW as shown in FIG. 4A.

  The control circuit 14 determines that the magnetic sensor 3 is close to the S pole of the rotor 1 based on the signal level L_LOW.

  If the rotation direction switching signal supplied from the forward / reverse selector switch 16 indicates normal rotation, the control circuit 14 drives the drive pulse signal O1 = HIGH, O2 as shown in FIGS. 4 (c) and 4 (d). = LOW is output (processing in step S16).

  The driver 15 amplifies the drive pulse signals O1 and O2, outputs a drive pulse signal of OUT1 = HIGH, OUT2 = LOW, and supplies a drive current to the drive coil 6. When a drive current flows through the drive coil 6, the stator magnetic pole 2p is magnetized to the S pole and the stator magnetic pole 2q is magnetized to the N pole.

  As the stator magnetic poles 2p and 2q are magnetized in this way, the rotor 1 rotates forward in the positive direction indicated by the arrow in FIG. As shown in FIGS. 4C and 4D, the control circuit 14 lowers the drive pulse signal O1, raises the drive pulse signal O2, and extinguishes the magnetism of the stator magnetic poles 2p and 2q after a predetermined time has elapsed. To do. However, the rotor 1 rotates forward as it is due to inertia and stops at the next stop position via the position indicated by Pos14.

  Next, as shown in FIG. 5A, when the rotor 1 is stopped at the position indicated by Pos21, the signal level of the detection signal of the magnetic sensor 3 is L_HIGH as shown in FIG. Become.

  Based on the signal level L_HIGH, the control circuit 14 determines that the magnetic sensor 3 is close to the north pole of the rotor 1 (“L_HIGH” in step S11).

  At this time, if the rotation direction switching signal supplied from the forward / reverse selector switch 16 indicates reverse rotation, the control circuit 14 indicates that the drive pulse signal O1 = HIGH as shown in FIGS. 5 (c) and 5 (d). , O2 = LOW is output (processing in step S14).

  The driver 15 amplifies the drive pulse signals O1 and O2, outputs a drive pulse signal of OUT1 = HIGH, OUT2 = LOW, and supplies a drive current to the drive coil 6. When a drive current flows through the drive coil 6, the stator magnetic pole 2p is magnetized to the S pole and the stator magnetic pole 2q is magnetized to the N pole.

  As the stator magnetic poles 2p and 2q are magnetized in this manner, the rotor 1 rotates in the reverse direction indicated by the arrow in FIG. As shown in FIGS. 5C and 5D, the control circuit 14 lowers the drive pulse signal O1 and raises the drive pulse signal O2 after a predetermined time has elapsed, and the magnetism of the stator magnetic poles 2p and 2q disappears. To do. However, the rotor 1 rotates in reverse as it is due to inertia and stops at the position indicated by Pos23 via the position of Pos22.

  When the rotor 1 rotates and stops at the position indicated by Pos23 shown in FIG. 5A, the signal level of the detection signal of the magnetic sensor 3 is L_LOW.

  The control circuit 14 determines that the magnetic sensor 3 is close to the N pole of the rotor 1 based on the signal level L_LOW.

  If the rotation direction switching signal supplied from the forward / reverse selector switch 16 indicates reverse rotation, the control circuit 14 drives the drive pulse signal O1 = LOW, O2 = as shown in FIGS. 5 (c) and 5 (d). HIGH is output (processing of step S17).

  The driver 15 amplifies the drive pulse signals O1 and O2, outputs a drive pulse signal of OUT1 = LOW, OUT2 = HIGH, and supplies a drive current to the drive coil 6. When a drive current flows through the drive coil 6, the stator magnetic pole 2p is magnetized to the N pole and the stator magnetic pole 2q is magnetized to the S pole.

  As the stator magnetic poles 2p and 2q are magnetized in this manner, the rotor 1 rotates in the reverse direction indicated by the arrow in FIG. As shown in FIGS. 5C and 5D, the control circuit 14 raises the drive pulse signal O1 and lowers the drive pulse signal O2 after a predetermined time has elapsed, and the magnetism of the stator magnetic poles 2p and 2q disappears. To do. However, the rotor 1 rotates in reverse as a result of inertia and stops at the next stop position via the position indicated by Pos24.

  As described above, according to the present embodiment, the magnetic sensor 3 determines the orientation of the rotor 1 in the initial state, and the control circuit 14 is supplied from the detection signal output from the magnetic sensor 3 and the forward / reverse selector switch 16. The drive pulse signal OUT is generated based on the rotation direction switching signal.

  Therefore, it is not necessary to output a drive pulse signal having a large pulse width in the initial state.

  In addition, since the orientation of the rotor 1 can be accurately detected by the magnetic sensor 3, it is possible to prevent reverse rotation even when there is a hand movement error.

  When the step motor 11 is used in a timepiece, the rotor 1 can be rotated at high speed non-intermittently when correcting the timepiece display. The operation in this case will be described.

  Hereinafter, the case where the N pole of the rotor 1 is close to the magnetic sensor 3 and is stationary and rotated in the forward rotation direction will be described.

The control circuit 14 determines the orientation of the rotor 1 based on the detection signal of the magnetic sensor 3.
When determining that the direction of the rotor 1 is N pole, the control circuit 14 determines whether the rotation direction is the normal rotation direction or the reverse rotation direction based on the rotation direction switching signal supplied from the forward / reverse selector switch 16.

  When it is determined that the rotation direction is the forward rotation direction, the control circuit 14 outputs drive pulse signals O1 = LOW and O2 = HIGH to be output, as indicated by Pos31 in FIG.

  The driver 15 amplifies the drive pulse signals O1 and O2, outputs a drive pulse signal of OUT1 = LOW, OUT2 = HIGH, and supplies a drive current to the drive coil 6. When a drive current flows through the drive coil 6, the stator magnetic pole 2p is magnetized to the N pole and the stator magnetic pole 2q is magnetized to the S pole.

  When the stator magnetic poles 2p and 2q are magnetized, the rotor 1 rotates forward in the direction of the arrow shown after Pos32 in FIG.

  The magnetic sensor 3 always outputs a detection signal to the control circuit 14 while rotating the rotor 1 at a high speed. Since the magnetic sensor 3 is disposed in the vicinity of a position shifted by 90 ° with respect to the dynamic magnetic center line L2, if the straight line connecting the N pole and S pole of the rotor 1 coincides with the dynamic magnetic center line L2, the magnetic The detection signal of the sensor 3 becomes zero.

  As indicated by Pos32 in FIG. 6, at the timing when the detection signal becomes zero, that is, when the straight line connecting the N pole and S pole of the rotor 1 coincides with the dynamic magnetic center line L2, the control circuit 14 Switch to O1 = HIGH and O2 = LOW.

  As shown by Pos33 in FIG. 6, the stator magnetic pole 2p is magnetized to the S pole and the stator magnetic pole 2q is magnetized to the N pole, and the rotor 1 continues to rotate further due to its inertia and magnetic force.

  As indicated by Pos34 in FIG. 6, when the straight line connecting the N pole and S pole of the rotor 1 again coincides with the dynamic magnetic center line L2, and the detection signal of the magnetic sensor 3 becomes zero, the control circuit 14 generates a drive pulse signal. Repeatedly switch to O1 = LOW and O2 = HIGH.

  By disposing the magnetic sensor 3 in the vicinity of the position shifted by 90 ° with respect to the dynamic magnetic center line L2 in this way, it is synchronized with the phase of the rotor 1 by the detection signal of the magnetic sensor 3 without newly providing a detection means. By switching the drive pulse signal, it is possible to perform non-intermittent high-speed rotation with higher speed and efficiency.

It is a figure which shows the structure of the pulse motor which concerns on embodiment of this invention. It is a block diagram of the motor drive circuit shown in FIG. 3 is a flowchart showing drive control processing executed by the control circuit shown in FIG. 2. It is a timing chart which shows the specific operation | movement when the rotation direction of a rotor is normal rotation. It is a timing chart which shows the specific operation | movement when the rotation direction of a rotor is reverse rotation. It is a timing chart which shows the operation | movement at the time of rotating a rotor at high speed (forward direction) non-intermittently.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotor 2 Stator 3 Magnetic sensor 11 Pulse motor 14 Control circuit

Claims (3)

A rotor in which N and S poles are magnetized in two poles;
A stator comprising a pair of stator magnetic poles for driving the rotor and having a hole through which the rotor passes;
A drive coil for exciting the stator;
A magnetic sensor that is arranged near the shaft surface of the rotor, detects a magnetic pole of the rotor adjacent thereto, and outputs a detection signal;
A control unit that determines the orientation of the rotor based on a detection signal output from the magnetic sensor, and that controls energization to the drive coil based on the determined orientation of the rotor and the instructed rotation direction; Prepared,
A pulse motor device characterized by that. The controller determines the orientation of the rotor based on a detection signal output from the magnetic sensor, and generates a drive pulse signal based on the determined orientation of the rotor and an instructed rotation direction. And determining the orientation of the rotor based on the detection signal output from the magnetic sensor before generating the drive pulse signal,
The pulse motor device according to claim 1. In the stator, the angle of the static stability line indicating the direction in which the rotor is stationary in a non-excited state with respect to the dynamic magnetic center line of the stator magnetic pole is 45 ° or more and 90 ° or less in the forward rotation direction. The pair of stator magnetic poles is formed on
The magnetic sensor is disposed in the vicinity of a position shifted by 90 ° with respect to the dynamic magnetic center line.
The pulse motor device according to claim 1 or 2, characterized in that.

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