JPS6056400B2 - Drive control method for pulse motor for watches - Google Patents

Description

[Detailed Description of the Invention] A directional circuit pulse motor used for watches consists of a permanent magnet rotor, a stator, and a drive coil, and has a stationary stable point at a constant angle from the center between the magnetic poles of the stator. It is driven by short alternating pulses and rotates step by step to move to the next stationary stable point.

This stationary stable point is the point where the potential energy between the rotor magnetic poles and the stator is minimum, and it is the magnetic pole center position of the permanent magnet rotor where the permanent magnet rotor is stably stopped when no driving pulse is applied. It is determined by the outer and inner circumferential shapes of the stator, the gap between the stator and the rotor, etc., and can be set at any arbitrary position, albeit within a narrow range, depending on the inner circumferential shape, for example, the position of the kerf. In addition, several types of pulse motors capable of forward and reverse rotation have been proposed, which are used to correct the pointers such as the second hand, minute hand, hour hand, etc., but all of them require two drive coils,
Three to four stators have to be used, which results in a large and thick volume, requires four-phase pulses for driving, and the circuit is complicated, making it difficult to implement. Furthermore, since the direction of rotation is controlled by changing the order in which the pulse phases are applied, there is a drawback that if the correspondence between the rotor magnetic poles and the pulse phases breaks down due to malfunction, the direction of rotation will change. The present invention aims to electromagnetically move the static stable point to an arbitrary position in a pulse motor having at least one static stable point composed of a permanent magnet rotor, a stator, and a drive coil. .

The present invention also provides a directional rotation pulse motor having at least one stationary stable J fixed point, which is composed of a permanent magnet rotor, a stator, and a drive coil, in which the stationary stable point is electromagnetically moved and then reversed. The purpose is to enable rotation in the opposite direction by applying a drive pulse. Examples will be described below.

FIG. 1 shows an example of a conventional fixed direction rotation pulse motor, in which 101 is a rotor, 102 and 103 are stators, and 10
Reference numeral 4 denotes a drive coil, and stationary stable points 107 and 108 are set by providing grooves on the inner periphery of the stator.

If the angle formed by the magnetic pole centers 115, 116 of the stators 102, 103 and the static stability points 107, 108 is the static stability angle α, then as will be described later, when α is small, the permanent If the phase of the magnet rotor and the drive pulse becomes reversed from the normal rotation due to a problem in the circuit, a large reverse driving force will be applied and the rotation will reverse. The limit magnetic pole center 115, 1 is reversed by this drive pulse of different polarity.
Assuming that the angle from 16 is the reversible rotation angle β, the stationary stability angle α is the reversible rotation because the clock motor must always maintain forward rotation even if there is a phase shift between the permanent magnet rotor and the drive pulse. It is set larger than the angle β. Generally, the static stability angle α can be set by the kerf position. For example, in Fig. 1, the straight line connecting the two grooves 105 and 106 and the
゛When the two magnetic pole centers N and S of the rotor are on perpendicular lines, the mutual pulling torque T(
θ) becomes the minimum, resulting in stationary stable points 107 and 108.
Therefore, the straight line connecting the two kerfs is rotated somewhat around the rotor center, that is, the kerfs 105 and 106 are arranged so that they approach the magnetic pole centers 115 and 116, respectively.
06, the static stability angle α can be set larger than the reversible rotation angle β. In this way, the static stability angle α is set larger than the reversible rotation angle β.

The reversible rotation angle β is determined by design factors, such as the distance between opposing stator magnetic poles, the gap between the stator inner diameter and the permanent magnet rotor outer diameter, and the like. FIG. 2 shows an embodiment of the pulse motor according to the present invention, in which 1 shows the forward rotation, and as in FIG. 1, 201 is a rotor, 202 and 203 are stators, and 204
By providing a cut groove on the inner circumference of the stator using the drive coil,
Stationary stable points 211 and 212 are set. ”ru.

The pulse motor shown in Figure 2 has the same motor main body as the conventional fixed-direction rotation motor shown in Figure 1, and in this case too, the static stability angle α is set larger than the reversible rotation angle β, and the permanent magnet rotation during steady state. This prevents reversal due to a phase shift between the drive pulse and the drive pulse. In order to reverse this pulse motor, it is sufficient to apply an initial operation to rotate the rotor somewhat so that the static stability angle α becomes smaller than the reversible rotation angle β, and then apply a reverse drive pulse. Here, as shown in FIG.
When a small excitation current is applied so that 203 is a weak south pole and stator 203 is a weak north pole, the permanent magnet rotor receives a weak rotational force in the clockwise direction, and the pulling torque between the rotor and stator increases. It moves in the positive direction by an angle γ until it reaches a point where it is balanced, and an equilibrium point 218 is reached as shown in FIG. If the movement angle γ>α−β, it means that the stationary stable point 211 has substantially moved beyond the reversible rotation position 213 to a region where rotation is possible in both forward and reverse directions, and then a reverse drive pulse is applied. This allows reverse rotation. FIG. 3 is an explanatory diagram of the pulse motor shown in FIG. 2 in a forward rotation state, and FIG. 4 is an explanatory diagram of the reverse rotation state.

FIG. 5 is a main configuration diagram of a crystal clock using a pulse motor of the present invention, in which 501 is a crystal oscillation circuit, 502 is a frequency dividing circuit, 503 is a waveform conversion circuit, 504 is a drive circuit, 505 is a drive coil, and 506 is a This is switch S.

Figure 6 shows an example of a waveform conversion circuit and a drive circuit, Figure 7 is a waveform diagram of each part, and Figure 8 is a torque curve versus rotation angle during forward rotation, where P1 is the driving force and T1 is the rotor. and the holding force due to the attractive force between the stator.

FIG. 9 shows a torque curve with respect to the rotation angle during reverse rotation, where P2 indicates the driving force, and P3 and P4 indicate the pulling torque T2, which is caused by a weak excitation current for moving the stationary stable point, and the holding force. The equation of motion of the pulse motor used in electronic watches can be approximately expressed here.

However, J: Moment of inertia of the rotor μ: Fluid resistance coefficient A (θ): Torque coefficient or electromechanical coupling coefficient T (0)
: Mutual pulling torque (holding force) between stator and rotor magnets θ:
Rotation angle 1 (t): Drive current L: Drive coil inductance E: Applied voltage P: Drive torque α: Initial phase angle of T with respect to the center of stator slit width α
indicates the time of forward rotation, and -α indicates the time of reverse rotation.

ρ(θ): Load There is.

In the pulse motor shown in Fig. 2, in the case of normal rotation, Fig. 2 1
In the state, the rotor 201 is at the static stable point 21 at the static stable angle
It is stationary at 1,212.

The stationary stable point 211 corresponds to R of the torque curve during normal rotation in FIG. As seen in equation (1), the load ρ(θ)
If the current is zero, the drive torque that actually acts on the rotor of the motor is the difference or sum of the drive torque P generated based on the drive current and the pull torque T(θ).

As shown by the driving torque curve P1 in the torque curve diagram for the rotation angle during normal rotation in FIG. The driving force QR increases. Therefore, when the static stability angle α is small, a drive pulse with a polarity opposite to that during normal rotation is applied to the drive coil due to a trouble in the circuit, and for example, in the state shown in FIG. When the drive coil is excited to become the N pole, the drive torque becomes a force that tries to rotate the rotor 101 counterclockwise, and since the initial drive force QR is large, it is necessary to overcome the pulling torque T1. It's reversed. When the static stability angle α is large, the initial driving force QR is small, and the driving force rapidly decreases with respect to the counterclockwise rotation angle, so the pulling torque T1
will become larger, and it will be impossible to overcome this and reverse the situation. The step motor for a watch has a static stability angle set to be larger than the reversible rotation angle β, which is the limit for reversing, to prevent it from reversing under normal usage conditions. In order to reverse this pulse motor in order to correct the hour hand, minute hand, and second hand, it is sufficient to set the static stability angle α to be smaller than the reversible rotation angle β by some means when applying the reverse drive pulse.
As shown in the drive torque curve diagram at the time of reverse rotation in Fig. 9, the second
When a small excitation current is passed through the drive coil 204 in FIG. 2 to drive in the forward direction, the rotor receives a weak forward rotational force.
It comes to rest at an equilibrium point 218 (point V on the graph) where the driving torque P3 and the pulling torque T2 are balanced. If the movement angle γ>α−β, the stationary stable point 211 has substantially moved beyond the reversible rotation position 213 to a region where rotation is possible in both forward and reverse directions, and then a reversal drive pulse is applied. This makes reversal possible. That is, when the rotor is at the point (2), if a driving pulse with a polarity opposite to the weakly excited pulse is applied, the initial driving force U (2) is large, so that reverse rotation is possible.

At this time, the magnitude of the pull torque curve T2 is V''1,■, which also becomes an auxiliary reverse rotation force.In other words, the sum of the generated drive torque and the pull torque becomes the initial drive torque, which ensures that reverse rotation is possible. The reason why the stable points 218 and 219 in FIG. φ2 is applied by the circuit shown in FIG. 6. In FIG.
D gates 603, 604, 605, 606, 0R gates 609, 613, 614, AND gates 611, 612
and switch S5O6, and the drive circuit is P-0
hM0S transistor 615, 616, 617, 61
8. Consists of N-ChMOS transistors 619, 620, and P-JchMOS transistor 617.
The N-ChMOS transistor 618 is set to a relatively high output resistance value.

505 is a drive coil.

During normal operation, the switch S is grounded to the high potential side of the power supply, and the FF6lO output is O(5), and the φ0,? bow is A.
Since it cannot pass through the ND gates 611 and 612, only Il and b2 are applied to the drive circuit. First, a φ1 pulse is applied to the drive coil 204, which excites the stator 202 to the S pole and the stator 203 to the N pole.The N pole of the rotor 201 is repelled by the N pole of the stator 203, and the S pole of 203 is attracted and rotates. The south pole of the child is attracted by the north pole of 203, and is repelled by the south pole of 202,
It receives rotational force in the forward direction (clockwise) and rotates as shown in FIG. 31. The rotor is rotated approximately 90 degrees from the rest position until the holding force T (θ) = 0 at position 307, point x in Figure 8, which is generally half the rotation angle of one step.
0) becomes positive and is pulled into the next stable point 312, point Z in FIG. 8, by the holding force. Even if the lower limit of the drive pulse width is cut off before the rotor reaches point x, rotation is still possible as long as the rotor can overcome the negative holding force and provide enough kinetic energy to reach point x. However, it is best to set this by considering the influence of load torque. Considering the upper limit of the pulse width, the sum of the driving force P1 and the holding force T1 reaches a position W where it is zero, but even if the driving pulse is cut off at this point, since T1 is positive, the rotor will exert a forward rotational force. There is no particular restriction on the length since the current is received and the current is directed toward the next stable point Z, but in order to reduce current consumption, a length of 16 mm or less is appropriate. As shown in FIG. 3, the N pole of the rotor 180 reaches the stationary stable point 312, point Z in FIG.

This is because the coefficient μ (fluid resistance coefficient) of the second term on the left side of the equation of motion (1) is relatively small, but if μ is increased to a certain extent, critical braking is also possible. When the φ2 pulse is applied to the drive coil in the state shown in FIG. 3, the stator 302
is excited to the north pole, 303 is excited to the south pole, the north pole of the rotor 301 is repelled by the north pole of the stator 302, and the south pole of the rotor 303 is attracted, the south pole of the rotor 301 is attracted to the north pole of the stator 302, It is repelled by the S pole of 303, receives a forward rotational force, rotates 1800 times, and returns to the state shown in FIG. 2.

Thereafter, the same state is repeated by alternating pulses to continue rotating in the forward direction.

Next, looking at the drive circuit, it is shown in Figure 6. The switch S5O6, which is linked to an external operating member such as a user, is grounded to the high potential side of the power supply, the output terminal a of FF6O8 is always O, and the output terminals D and e of the NAND gates 604 and 605 are 1. , input signals φ1 and φ2 are NAN
It is applied to the drive circuit 504 via the D gates 603 and 606.

When no signal is applied, the gate input of the MOs transistor of the drive circuit is 1, the N-ChMOS transistors 619 and 620 are on, and both ends 621 and 622 of the drive coil 505 are at zero level. When b1 is applied now, P1ChMOS transistor 6
15 is on, i1 is also connected to P- through the 0R gate 613.
It is applied to the common manual gates of the ChMOS transistor 617 and the N-ChMOS transistor 619, turning the transistor (hereinafter referred to as Tr) 617→on Tr6l9→off. However, Tr6l7, Tr6l. , 8 are set to be high, at least higher than the DC resistance of the drive coil, the drive current mainly flows through the path of Tr6l5→621→drive coil→622→Tr62O. Similarly, when B2 is applied, Tr6l6 and 618 are turned on and Tr62O is turned off, and the drive current is mainly driven by Tr6.
It flows through the path 16→622→drive l coil→621.
A two-phase alternating pulse current flows through the drive coil, and the pulse motor rotates in the forward direction. As an example of reverse rotation, consider the state shown in FIG. 2 1. This is a state in which the motor rotates by one step from the state shown in FIG. 3 2 due to the application of pulse φ2 and remains stationary.

At this time, if t in Fig. 7 is linked to switch S5O6 or by operating an external operating member such as a user, and the switch S is set to the low potential side, S = 0, and the output terminal a of FF6O8 becomes 1. . The output terminal b of FF6O7 is the NAND gate 606 of the φ2 pulse 701 applied before t=t1.
Since b=1 due to the output 2 of the output terminal g, the output terminal d of the NAND gate 604 becomes 0, and the next φ
1 pulse 702 is blocked by NAND gate 603. On the other hand, FF6lO output h=1, φ0, I0
can pass through AND gates 611 and 612, and 0R
It is applied to the drive circuit via gates 613 and 614.

When φo is applied to the common gate of Tr6l7 and Tr6l9, Tr6l7 → on Tr6l9 → off, and as shown in FIG.
04, a minute voltage is applied to the drive coil, and as shown in FIG.
The stator 203 is slightly excited to the north pole, and the stator 202 is slightly excited to the south pole. The rotor rotates somewhat in the positive direction and is balanced at position V (VO■=■■2) at 218 in Figure 2, where the sum of the pulling torque P3 due to the weak excitation current in Figure 9 and the holding force T2 is 0 (VO■ = ■■2). to become stationary and stable. On the other hand, since the other output terminal C of FF6O7 is 0, the output terminal e of 605 of the N, AND gate is
1, φ2 passes through the NAND gate 606, and a B2 pulse 703 appears at the output terminal g.

This B2 resets the output terminal a of FF6O8 to 0, and from then on, φ1 can pass through. Therefore, the second
In the state shown in FIG. 2, the I2 pulse is applied to the drive circuit, and as shown in FIG.
As shown, the stator 403 becomes the S pole and the stator 402 becomes the N pole, and the N pole of the rotor 401 is repelled by the N pole of the stator 402.
The S pole of the rotor 401 is attracted by the S pole of the stator 403, the S pole of the rotor 401 is attracted by the N pole of the stator 402, is repelled by the S pole of the stator 403, receives a leftward (counterclockwise) rotational force, and is reversed.

The driving force becomes zero at point 410 in Fig. 4 1 and Y'' in Fig. 9, but at this point the rotor has sufficient kinetic energy to overcome the negative holding force, so it easily becomes Y''. From this point, the rotor reaches the point x'' where the holding force T=0, and moves towards the next stable point due to the rotor's own kinetic energy and the positive holding force.

The lower limit of the pulse width of the drive pulse can be set in the same way as for normal rotation, but the upper limit is set at the position W''(W''1W''=W ″W″2
) is the negative region of T2, so if the driving pulse width is sufficiently wide, the rotor will return to around point W'' during pulse application, and when the pulse is cut off, there is a possibility that it will return to the initial stable point 211, point ■. Therefore, it is not appropriate to use a pulse with a pulse width that is too wide. In this case as well, a pulse width of 16 milliseconds or less is appropriate. When the drive pulse φ2703 is cut off, the rotor has exceeded the x'' point. are Tr6l8 and Tr62 of the drive circuit
applied to the common gate of O, Tr6l8→on, Tr
62O→OFF, a minute voltage is applied to the drive coil as shown in FIG. 7 706, and as shown in FIG. Position V″ where the sum of pulling torque P4 due to excitation current and holding force T2 is 0 (V″1■″=■″V″2), Fig. 4 2
At 419, it reaches equilibrium and becomes stable. When the I pulse is applied to the drive coil in this state, the stator 403 becomes the N pole,
The stator 402 is excited to the south pole, the north pole of the rotor 401 is attracted by the south pole of the stator 402, the north pole of 403 is repelled, the south pole of the rotor 401 is repelled by the south pole of the stator 402, 403 The N pole is attracted and receives a rotational force in the opposite direction, rotating 800 times and returning to the state shown in FIG. 2. Thereafter, the same state is repeated by alternating pulses and rotation continues in the opposite direction. An example has been shown in which φ2 is applied once again to the drive coil for forward rotation → reverse rotation, but the direction of rotation can be easily changed by applying once again the pulse of the pulse phase that was applied just before the switch S was grounded.

In the example, in steady drive, the stationary stable point of the pulse motor rotating in a fixed direction was electromagnetically moved by an angle γ in the forward rotation direction (clockwise) to enable rotation in the reverse direction. It is also possible to improve the output torque of the pulse motor during forward rotation by moving the stationary stable point.

It is also possible to set different electromagnetic static stable points during forward rotation and reverse rotation. Further, when the static stability angle is set to be less than β to enable forward and reverse rotation, the output torque of the pulse motor during reverse rotation can be increased by moving the static stability point during reverse rotation.

Since a small current is passed for excitation during reverse rotation, the current consumption increases somewhat, but this is not a problem since it is used infrequently. Also,
It is possible to set it so that maximum efficiency can be obtained even during reverse rotation. The static stability angle can be moved at the inflection point of the time-keeping force, so it is possible to move about half of one step, and it is ±9 in electrical angle.
Can move 0te.

If configured as in the present application, the stationary stable point of the pulse motor can be moved to the position of maximum efficiency.

Further, by moving the stationary stable point of a conventional fixed direction rotation pulse motor, reverse rotation can be made possible.

Furthermore, by setting the static stability angle α to be larger than both rotational regions β, it is possible to prevent reverse rotation even if the correspondence between the pulse phase and the rotor magnetic poles is broken due to malfunction, and mechanical It is possible to configure a forward/reverse pulse motor that does not require a reverse rotation prevention mechanism.

Furthermore, by applying quick correction drive pulses with a higher frequency than during steady drive to the drive coil, it is possible to make quick corrections of the hour hand, minute hand, second hand, etc. In conjunction with this, it is possible to construct a wristwatch that does not need to be used.

Furthermore, by providing a memory circuit for the positions of the hour hand, minute hand, second hand, etc., and applying as many quick-correction drive pulses as the number indicated by the memory circuit to the drive coil during correction, it is possible to instantly correct the hands to the set value. .

``Brief Description of the Drawings Figure 1 shows a conventional pulse motor, Figure 2 shows an embodiment of the pulse motor according to the present invention, Figure 3 is an explanatory diagram of the pulse motor according to the present invention in a forward rotation state, and Figure 4 shows an example of the pulse motor according to the present invention. The figure is also an explanatory diagram of the state of reverse rotation, Figure 5 is a main configuration diagram of a crystal clock using a pulse motor according to the present invention, Figure 6 is an example of a waveform conversion circuit and drive circuit, and Figure 7 is a waveform Figure, 8th
The figure shows the torque curve during normal rotation, and FIG. 9 shows the torque curve during reverse rotation.

101, 201, 301, 401... rotor,
102, 202, 302, 402, 103, 203, 3
03,403...Stator, 104,204,30
4,404... Coil, 503... Waveform conversion circuit, 504... Drive circuit, 506...
...Switch S.

Claims (1)

[Claims] 1 Consisting of a two-pole permanent magnet rotor, a pair of stators, and one drive coil, the centers of the magnetic poles of the pair of opposing stators and the center of the magnetic poles of the permanent magnet rotor stop at a predetermined angle. In a pulse motor that advances one step per pulse by applying alternating pulses of different polarity to the drive coil, the permanent magnet rotor is applied to the drive coil until it reaches the limit static stability angle where the permanent magnet rotor is reversed by the drive pulses of different polarity. The permanent magnet rotor is electromagnetically moved in the forward rotation direction by applying output pulses from the pulse supply circuit, and has a pulse supply circuit that sends a minute average excitation current that is large enough to move the permanent magnet rotor in the forward rotation direction. 1. A method for controlling the drive of a pulse motor for a watch, characterized in that, after the motor has moved, reverse rotation is enabled by applying a reverse drive pulse.