JP2571501B2 - Driving method of watch step motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control method for a step motor for a timepiece, and more particularly to a reverse control method for a single-phase drive coil type step motor.

[0002]

2. Description of the Related Art Today, in analog watches using a crystal oscillator, a step motor using a pulse signal obtained by dividing a high-precision reference frequency signal output from the crystal oscillator is frequently used. In many cases, a single-phase drive coil type step motor is used.

In recent years, even with this single-phase drive coil type step motor, forward rotation and reverse rotation are made possible by adjusting the waveform of the applied voltage (for example, Japanese Patent Publication No.
2-43148). As shown in FIG. 3, this single-phase drive coil type step motor capable of forward and reverse rotation has a stator 1 having magnetic poles excited by a drive coil 17.
The gap between the rotor 5 and the rotor 11 having a magnetic pole as a magnetized permanent magnet is unbalanced, and when the drive coil 17 is not energized, the gap between the N pole and the S pole of the rotor 11 with the pole of the stator 15 is small. The line AB is defined as a stable position (hereinafter referred to as a non-excitation stable position), and when the drive coil 17 is energized, the N and S poles of the rotor 11
In a structure in which the CD line direction deviated by a predetermined angle θ from the electromagnetically stable position at a position where the gap with the magnetic pole is slightly larger is set as a stable position (hereinafter referred to as an electromagnetically stable position), for example, as shown in FIG. A voltage is applied to the drive coil 17 so as to rotate the rotor 11 clockwise, and a repulsive attraction force is applied between the magnetic poles of the rotor 11 and the stator 15 to rotate the rotor 11 so that the single pole is formed. In this machine, a step of 180 degrees is performed with one pulse.

At the time of forward rotation, as shown in FIG. 4A, for example, a positive pulse is applied to the drive coil 17 as an applied voltage pulse to rotate the rotor 11 to nearly 90 degrees in the normal rotation direction. And this applied voltage pulse is
The rotor 11 is added to the drive coil 17 by limiting to a time width in which the rotor 11 is rotated by nearly 90 degrees from the non-excitation stable position,
After the stop of the positive pulse, when the rotor 11 rotates by more than 90 degrees due to inertia, the rotor 11 continues to rotate to the non-excitation stable position advanced by 180 degrees, stops at the non-excitation stable position rotated by 180 degrees, and proceeds. Complete. Then, when a negative pulse is applied to the drive coil 17 under the same conditions as the positive pulse so as to excite the electrodes to the opposite polarity, the rotor 11 further rotates by 180 degrees, and in this manner, the rotor 11 sequentially rotates in the forward direction for each pulse. It rotates by 180 degrees.

In the reverse rotation of the stepping motor, for example, as shown in FIG. 4B, the rotor 11 is first applied with a narrow positive pulse as a first pulse so as not to advance in the normal rotation direction. The rotor 11 is slightly rotated in the forward rotation direction, and subsequently, a negative pulse having a polarity opposite to that of the first pulse is applied as a second pulse, thereby attracting the magnetic poles of the rotor 11 in the direction of the first stop position and applying a reverse rotation torque to the rotor 11. The second pulse is applied until the rotor 11 rotates in the reverse direction and the magnetic pole of the rotor 11 passes through the non-excitation stable position, which is the first stop position, and further rotates in the reverse rotation direction by θ to reach the electromagnetic stable position. When the rotor 11 reaches the electromagnetically stable position, the positive pulse is again set as the third pulse and the drive coil 17
When the rotor 11 reversely rotated by the second pulse and the third pulse rotates in the reverse rotation direction more than 90 degrees from the non-excitation stable position, which is the initial stop position, in combination with the inertia of the rotor 11, the first stop is performed. The rotor 11 rotates toward a non-excitation stable position, which is a position shifted by 180 degrees from the position, and the rotor 11 stops at a non-excitation stable position, which is a position rotated a half turn in the reverse direction from the first stop position. Next, a negative pulse having a width small enough not to advance in the forward direction is applied as a first pulse, a positive pulse having a polarity opposite to that of the first pulse is continuously applied as a second pulse, and a negative pulse having a polarity opposite to that of the second pulse is applied. By continuously applying the negative pulse as the third pulse, the rotor 11 can be further advanced backward by 180 degrees.

[0006]

As described above, a single-phase drive coil type step motor is suitable for a drive motor for a timepiece because of its small size, and can be rotated forward and backward by waveform control. Used for clock bodies. However, a single-phase drive coil type step motor has a structure originally suitable for setting the rotation direction to one direction, and although it is easy to mechanically improve the torque characteristics of the forward rotation, In improving the performance, it has been difficult to improve the reverse rotation characteristics without lowering the performance during normal rotation.

[0007] Today, there is a demand for a clock body capable of reversing the hands promptly even if the frequency of use is low. Needless to say, there is an increasing demand for stable reverse rotation. The present invention provides a stepping motor control method which responds to such a demand, and which more reliably and stably performs reverse rotation of a conventional single-phase drive coil type stepping motor capable of normal and reverse rotation. It is.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to driving a single-phase drive coil type step motor capable of rotating forward and reverse.
A second pulse having a pulse width wider than that of the first pulse and having a polarity opposite to that of the first pulse is applied following the first pulse having a pulse width that does not achieve a step while driving the rotor in the normal rotation direction,
A third pulse having a polarity opposite to that of the second pulse is applied following the second pulse, and a fourth pulse having a polarity opposite to that of the third pulse is applied after the third pulse and has a width smaller than that of the second pulse or the third pulse. To rotate the rotor 180 degrees in the opposite direction.

[0009]

According to the present invention, even if the angle difference θ between the stationary position and the electromagnetically stable position of the rotor is small by rotating the rotor in the forward direction by the first pulse that does not achieve the forward rotation, Since the distance between the magnetic pole of the stator and the magnetic pole of the stator can be increased once, the rotor can be strongly started to rotate in the reverse rotation direction by the second pulse.
Since the reverse rotation torque is further continuously applied to the rotor by the pulse, the reverse rotation torque can be applied for a long time.
Since the fourth pulse having a polarity opposite to that of the third pulse is applied following the pulse to rotate the rotor 180 degrees, the rotation of the rotor is braked by the fourth pulse applied before the rotation of 180 degrees, and one step is performed. Even if the rotation in the first half is high torque and high speed, the rotation is decelerated in the second half, and the rotation of the rotor can be easily limited to 180 degrees.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is directed to a stator 15 provided with a single-pole rotor 11 and a single-phase driving coil 17 having an angle difference .theta. Between the electromagnetically stable position and the non-excitation stable position shown in FIG.
This is a method of driving a step motor for a timepiece constituted by the following steps. As shown in FIG.
The rotor 11 is rotated by 180 degrees by continuously applying the pulses as a set.

The first pulse 21 of the four pulses
Is applied to the drive coil 17 as a polarity for rotating the rotor 11 in the normal rotation direction, and its pulse width is a short pulse width that does not rotate the rotor 11 by 90 degrees.
It is preferable that the pulse width is limited to a pulse width at which the advance of the rotor 11 is not achieved only by the first pulse 21. Usually, the pulse width is set to a pulse width enough to rotate the rotor 11 by about 20 to 60 degrees. The pulse width can be easily set.

A second pulse 22 applied to the drive coil 17 subsequent to the first pulse 21 is applied to the drive coil 17 with a polarity opposite to that of the first pulse 21, and the second pulse 22 is temporarily Rotor 1 rotated in the forward direction
The application time is regulated in accordance with the time when one magnetic pole returns to the vicinity of the electromagnetically stable position. The first pulse 21 and the second pulse 22 rotate the rotor 11 once in the normal rotation direction, and then rotate the rotor 11 in the reverse direction to rotate the rotor 11 to the electromagnetically stable position shifted by θ from the initial stop position. Therefore, depending on only the first pulse 21, the rotor 11 rotates by 90 degrees or more due to inertia after the first pulse 21 is stopped, and is attracted to the next non-excitation stable position to achieve a rotation of 180 degrees, that is, a step. Even if the first pulse 21 is set to a pulse width that causes the second pulse 22 following the first pulse 21
As a result, braking is applied to the rotation in the normal rotation direction, and the second pulse 22
The rotor 11 rotates in the reverse direction due to the attraction force, and the pulse width of the first pulse 21 and the second pulse 22 is regulated so that the step is not achieved by being returned to the electromagnetically stable position shifted by θ from the initial stop position. It is also possible to keep.

Further, the third pulse 23 applied to the drive coil 17 successively to the second pulse 22 has a polarity opposite to that of the second pulse 22, and the first stop position after the rotor 11 has passed the electromagnetically stable position. The pulse width is regulated in accordance with the time until the reverse rotation from 90 to 90 degrees. By applying the fourth pulse 24 having the opposite polarity to the third pulse 23 following the third pulse 23, The braking is applied to the rotation, and the pulse width of the fourth pulse 24 is smaller than the pulse widths of the second pulse 22 and the third pulse 23, and the rotor 11 is shifted at the non-excitation stable position 180 degrees from the first stop position. Is made close to zero.

The reason why the third pulse 23 is applied between the time when the electromagnetic pulse is passed through the electromagnetically stable position and the position where the third pulse 23 is reversely rotated by 90 degrees with respect to the first stop position is that the mechanical resistance of the rotor 11 and the third pulse 23 are applied. When the load of the drive motor is extremely small, the fourth pulse 24 enables the deceleration in which the speed at the non-excitation stable position 180 degrees from the first stop position is close to 0 even if the initial speed of the rotor 11 is considered. Therefore, the rotor 11 can be stopped quickly.

When the mechanical rotation resistance and the load on the rotor 11 are large, the time for applying the third pulse 23 to the drive coil 17 is increased, and the rotor 11 is moved 90 degrees from the first stop position.
The speed of the rotor 11 at the non-excitation stable position shifted by 180 degrees can be made close to 0 by the braking of the fourth pulse 24 while the application of the third pulse 23 is continued to a range exceeding the degree.

The third pulse 23 to the fourth pulse 24
When the rotor 11 is moved 90 degrees from the first stop position,
The time required to reach the position rotated by one degree facilitates the setting of the pulse width.
Even if the application of the third pulse 23 is continued until the rotor 11 reversely rotates 90 degrees from the first stop position, the fourth pulse 2
4 applies braking to the rotation of the rotor 11,
When the motor 1 reaches the non-excitation stable position rotated 180 degrees from the initial stop position, the rotation speed is reduced, the vibration can be reduced at the time of stop, and a quick stop can be performed. The pulse width of the four pulses 24 should be narrower than the pulse widths of the second pulse 22 and the third pulse 23 so as not to apply too much braking, and to reduce the rotation speed at a position that is a half rotation from the first stop position. It is enough to keep it low.

As described above, in this embodiment, the deviation angle θ between the position of the magnetic pole where the rotor 11 is stopped and the electromagnetically stable position is set to the first angle.
The rotor 11 is rotated by 180 degrees by applying a brake to the rotor 11 by a fourth pulse 24 while maintaining the reverse torque by the third pulse 23 while increasing the reverse torque by the second pulse 22 and increasing the reverse torque by the second pulse 22. Since the speed at the non-excitation stable position is close to 0, the reverse rotation torque is increased, so that the rotor 11 can be quickly reversely rotated, and the rotor 11 can be quickly stopped at the non-excitation stable position. As shown in FIG. 2, when the rotor 11 is rotated in reverse by three conventional pulses, the rotation speed of the rotor 11 is set at a non-excitation stable position at a position rotated 180 degrees from the initial stop position due to mechanical resistance. While it was necessary to adjust the application time of the third pulse so as to approach 0,
When the application time of the third pulse is extended and the fourth pulse is not applied, the rotation speed at the non-excitation stable position to be stopped is high,
Even if a strong reverse rotation torque is generated in the rotor 11 by the third pulse to such an extent that vibration occurs when the rotor 11 stops, a rapid reverse rotation step can be performed by braking the fourth pulse.

In this embodiment, as described above, a strong reverse torque is generated in the rotor 11 by the second pulse 22 and the third pulse 23, and the reverse pulse is generated by the four pulses so as to apply braking by the fourth pulse. A strong reverse torque is generated in the rotor 11 by the second pulse 22 and the third pulse 23, so that a reliable step is performed even when the battery is exhausted and the power supply voltage is slightly lowered. Even if the viscosity of the oil is slightly increased due to the temperature drop and the mechanical resistance increases, or if the resistance value of the coil increases and the magnetic flux decreases, the reverse run can be performed without fail. The voltage range and the operating temperature range can be widened.

Further, a second pulse 22 and a third pulse 23
Makes the rotation of the rotor 11 reverse quickly, and
Since the rotor 11 is quickly decelerated and stopped by the pulse 24, the reverse rotation of 180 degrees can be quickly completed, the reverse rotation every 180 degrees can be reliably performed, and a large number of continuous rotations can be performed in a short time. Therefore, there is an advantage that the response frequency can be improved as a result.

[0020]

As described above, the present invention relates to a method in which four pulses are used as a set to perform reverse advancing, and the second pulse and the third pulse are used to quickly and reliably perform the reverse rotation. As a result, since the braking of the rotor is stopped more reliably, the range of operating voltage and operating temperature can be widened, and the response frequency can be increased to enable stable reverse rotation.

[Brief description of the drawings]

FIG. 1 is a graph showing a pulse application state according to the present invention.

FIG. 2 is a graph showing a rotation state showing a control method according to the present invention and a conventional reverse rotation by three pulses.

FIG. 3 is a diagram showing a structure of a step motor controlled according to the present invention.

FIG. 4 is a diagram showing an example of a conventional step motor rotation control method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotor 15 Stator 17 Drive coil 21 1st pulse 22 2nd pulse 23 3rd pulse 24 4th pulse

Claims (1)

(57) [Claims] 1. A stator having a single-phase driving coil and a rotor having a single-pole permanent magnet formed by magnetization, and a gap between the magnetic poles of the stator and the rotor formed in an unbalanced manner. In a drive control method for a forward / reverse rotatable step motor having an electromagnetic stable position and a non-excitation stable position, a first pulse having a pulse width that does not cause the rotor to advance is applied to the drive coil, and the first pulse is applied to the first pulse. Subsequently, a second pulse having a polarity opposite to the first pulse is applied to the drive coil, a third pulse having a polarity opposite to the second pulse is applied to the drive coil following the second pulse, and a third pulse is applied to the drive coil following the third pulse. The fourth pulse having a polarity opposite to that of the three pulses and having a width smaller than that of the second pulse or the third pulse is applied to the drive coil, thereby rotating the rotor 180
A method of driving a step motor for a timepiece, wherein the step motor is rotated in reverse.