HK1262711B - Timepiece, electronic device, and control method of timepiece - Google Patents

Description

Clock, electronic device, and clock control method

Technical Field

The present invention relates to a clock, an electronic device and a control method of the clock.

Background Art

Clocks and watches are sometimes equipped with a motor unit for moving the hour, minute, and second hands. The motor unit includes a stepping motor that rotates the hands. When pulses from a drive control unit (driver IC) are applied to the coil, the stepping motor's rotor rotates forward or reverse.

Regarding stepping motors with a single coil, when the rotor is reversed, after temporarily rotating the rotor in the forward direction from a stationary position, the rotor is then rotated in the reverse direction by the reaction of returning to the stationary position (for example, see Patent Documents 1 and 2). Therefore, the rotor performs more complex movements during reverse rotation than during forward rotation. Furthermore, the pulses applied to the coils during reverse rotation (hereinafter referred to as reverse rotation pulses) are more complex than those applied to the coils during forward rotation.

Patent Document 1: Japanese Patent Application Laid-Open No. 55-33642

Patent Document 2: Japanese Patent Application Laid-Open No. 2014-117028

However, the motor unit can be installed in a variety of timepieces. The power supply of a timepiece sometimes varies depending on the type of timepiece. When the type of power supply varies, the voltage applied to the coil of the stepping motor varies. Therefore, the motor unit needs to be able to cope with the various power supplies of the timepiece to which it is installed. In other words, the stepping motor needs to use pulses of various voltages to accurately rotate the rotor forward and reverse. In particular, compared to the forward drive, the reverse drive of the stepping motor applies complex pulses to the coil. Therefore, when the voltage of the pulse applied to the coil changes, it may be difficult to accurately reverse the rotation.

Summary of the Invention

Therefore, the present invention provides a timepiece, an electronic device, and a timepiece control method that can ensure the reverse rotation accuracy of a rotor even when the voltage applied to the coil of a stepping motor changes.

The clock of the present invention is characterized in that it has: a voltage detection unit, which detects the voltage applied to the stepping motor that drives the pointer and outputs the voltage detection result; and a first control unit, which is a control unit that uses a reversal pulse to reverse the rotor of the stepping motor, wherein the reversal pulse includes a first pulse with the same polarity as the forward rotation pulse that causes the rotor to rotate forward, a second pulse with an opposite polarity to the first pulse, and a third pulse with an opposite polarity to the second pulse, and the first control unit controls the rotor to be reversed using the third pulse with a pulse width set corresponding to the voltage detection result.

In the above-mentioned clock, preferably, the clock has: a storage unit, which stores the correspondence between multiple third pulse levels and the voltage of the voltage detection result, and the multiple third pulse levels are related to the pulse width of the third pulse; and a second control unit, which instructs the first control unit to use the third pulse to reverse the rotor, wherein the pulse width of the third pulse is set according to the correspondence between the third pulse level and the voltage of the voltage detection result corresponding to the voltage detection result.

In the above-mentioned clock, preferably, the clock is formed to be capable of carrying two or more power supplies with different voltage ranges of output voltages, and the correspondence between the third pulse level and the voltage of the voltage detection result is stored in the storage unit, and the third pulse level includes a voltage amplitude that is larger than the fluctuation amplitude of the output voltage of each of the two or more power supplies.

In the above-mentioned timepiece, it is preferable that the correspondence between the third pulse level and the voltage of the voltage detection result is set so that the pulse width of the third pulse decreases as the voltage of the voltage detection result increases.

In the above-mentioned clock, preferably, the storage unit also stores a correspondence between multiple first pulse levels and the voltage of the voltage detection result, and the multiple first pulse levels are related to the pulse width of the first pulse. The second control unit instructs the first control unit to use the third pulse and the first pulse to reverse the rotor, wherein the pulse width of the third pulse is set in correspondence with the voltage detection result according to the correspondence between the first pulse level and the voltage of the voltage detection result, and the pulse width of the first pulse is set in correspondence with the voltage detection result.

In the above-mentioned clock, preferably, the correspondence between the third pulse level and the voltage of the voltage detection result is set so that the pulse width of the third pulse decreases as the voltage of the voltage detection result increases, and the correspondence between the first pulse level and the voltage of the voltage detection result is set so that the pulse width of the first pulse decreases as the voltage of the voltage detection result increases.

In the above clock, preferably, the third pulse includes: a first-half pulse constituting the first half of the third pulse; and a second-half pulse constituting the second half of the third pulse and being a chopping pulse having a smaller duty cycle than the first-half pulse.

In the above-mentioned timepiece, it is preferable that the timepiece includes a support body, the first control unit is provided on the support body, and the second control unit is provided separately from the support body.

In the above timepiece, it is preferable that the first control unit applies a demagnetization pulse having the same polarity as the first pulse to the stepping motor before applying the first pulse to the stepping motor.

The electronic equipment of the present invention is characterized by being constituted by the above-mentioned timepiece.

The control method of the clock of the present invention is characterized in that it has the following steps: a voltage detection step, in which the voltage detection unit detects the voltage applied to the stepping motor that drives the pointer and outputs the voltage detection result; and a reversal step, in which the first control unit uses a reversal pulse to reverse the rotor of the stepping motor, wherein the reversal pulse includes a first pulse with the same polarity as the forward rotation pulse that causes the rotor to rotate forward, a second pulse with opposite polarity to the first pulse, and a third pulse with opposite polarity to the second pulse. In the reversal step, the rotor is reversed using the third pulse with a pulse width set corresponding to the voltage detection result.

According to the present invention, a timepiece, an electronic device, and a timepiece control method can be provided that can ensure reverse rotation accuracy of a rotor even when a voltage applied to a coil of a stepping motor varies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a block diagram showing a configuration example of a timepiece according to an embodiment.

FIG2 is a top view of a stepper motor.

FIG. 3 is a diagram illustrating an example of a forward rotation pulse according to the embodiment.

FIG. 4 is an operation diagram illustrating a forward rotation operation of the stepping motor according to the embodiment.

FIG. 5 is a diagram showing an example of a forward fast-forward pulse according to the embodiment.

FIG. 6 is a diagram illustrating an example of an inversion pulse according to an embodiment.

FIG. 7 is an operation diagram illustrating a reverse rotation operation of the stepping motor according to the embodiment.

FIG. 8 is an operation diagram illustrating a reverse rotation operation of the stepping motor according to the embodiment.

FIG. 9 is an operation diagram illustrating a reverse rotation operation of the stepping motor according to the embodiment.

FIG. 10 is an operation diagram illustrating a reverse rotation operation of the stepping motor according to the embodiment.

FIG. 11 is a table showing an example of the relationship among the voltage of the voltage detection result, the level of the inversion pulse, and the pulse width of the inversion pulse.

FIG12 is a flowchart of the processing of the timepiece according to the embodiment.

FIG. 13 is a diagram showing the relationship between the pulse width of each of the first pulse and the third pulse of the inversion pulse and the voltage range that can drive the stepping motor.

Description of labels

1: Clock (electronic device); 3: First pointer (pointer); 4: Fifth pointer (pointer); 5: Third pointer (pointer); 10: Power supply unit (power supply); 20: Voltage detection unit; 50: Storage unit; 60: Main control unit (second control unit); 110: Support body; 120: Stepping motor; 131: Rotor; 150: Drive control unit (first control unit).

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. In the following description, structures having the same or similar functions are denoted by the same reference numerals. In addition, repeated descriptions of these structures may be omitted.

The timepiece 1 of this embodiment is an analog timepiece with hands, or an electronic device (smart watch, wearable terminal, etc.) In the following embodiment, an example in which the timepiece 1 constitutes an electronic device such as a smart watch is described.

FIG1 is a block diagram showing a configuration example of a timepiece according to an embodiment.

1 , the timepiece 1 includes hands 3 to 5 , a power supply 10 , a voltage detector 20 , an oscillation circuit 30 , a frequency divider circuit 40 , a storage 50 , a main control unit 60 (second control unit), and a motor unit 100 .

The hands 3 to 5 are a first hand 3, a second hand 4, and a third hand 5. The first hand 3 is, for example, an hour hand. The second hand 4 is, for example, a minute hand. The third hand 5 is, for example, a second hand. The hands 3 to 5 are rotatable relative to the motor unit 100.

The power supply unit 10 supplies power to the main control unit 60 and the drive control unit 150 (first control unit) described later of the motor unit 100. A power source such as a primary battery, a secondary battery, etc. is configured in the power supply unit 10. A solar panel can also be used as a secondary battery. In this embodiment, the power supply unit 10 of the clock 1 is capable of handling more than two power sources. That is, the clock 1 is formed to be able to carry more than two power sources. The voltage range of the output voltage (terminal voltage) of each power source is different. For example, generally speaking, the output voltage of a primary battery and a secondary battery respectively decreases with the depth of discharge, and thus has different voltage range segments.

The voltage detection unit 20 detects the output voltage (hereinafter referred to as the power supply voltage) of the power supply unit 10 . The voltage detection unit 20 outputs the voltage detection result to the main control unit 60 .

The oscillation circuit 30 is a circuit that realizes an oscillator by combining with a crystal resonator, and outputs the generated signal of the first frequency to the frequency dividing circuit 40 .

The frequency dividing circuit 40 divides the signal of the first frequency outputted from the oscillation circuit 30 into a desired frequency, and outputs the divided signal to the main control unit 60 .

The storage unit 50 is, for example, a nonvolatile storage medium such as a RAM (Random Access Memory) or a ROM (Read Only Memory). The data stored in the storage unit 50 will be described below.

The main control unit 60 controls each component of the timepiece 1. The main control unit 60 operates using the timing of a signal generated by a drive frequency based on the first frequency. The main control unit 60 is, for example, a CPU (central processing unit). The main control unit 60 stores, in a storage unit, definitions of instruction signals for driving the motor unit 100. Based on the voltage detection results output by the voltage detection unit 20 and the data stored in the storage unit 50, the main control unit 60 outputs an instruction signal for driving the motor unit 100 to the drive control unit 150 of the motor unit 100.

The motor unit 100 includes a support body 110 , a plurality of stepping motors 120A, 120B, and 120C, a plurality of gear trains 140A, 140B, and 140C, and a drive control unit 150 .

The support body 110 forms the outer contour of the motor unit 100. It supports the various components of the motor unit 100, including the stepping motors 120A, 120B, and 120C, the gear trains 140A, 140B, and 140C, and the drive control unit 150. The support body 110 is constructed as a separate unit that can be attached to and detached from the watch body. This design is also known as a cassette or cartridge type. In this case, the motor unit 100 is a semi-finished product or intermediate product, while the watch body is a finished product.

The support body 110 includes a bottom plate serving as a substrate or base, a support plate that presses down the components arranged on the bottom plate from the opposite side, and other components, such as a housing portion and bearings for engaging the rotating shafts of the stepping motors 120A, 120B, and 120C. A substrate is arranged on the bottom plate, and wiring, an input unit, a drive control unit, stepping motors 120A, 120B, and 120C, and gear trains 140A, 140B, and 140C are arranged on the substrate. These components are supported by the support plate to form a unit. Furthermore, electrodes serving as connection terminals are arranged on the bottom plate to electrically connect the electronic components within the motor unit 100 to the outside of the motor unit 100 (the watch body side).

The plurality of stepper motors 120A, 120B, and 120C include a first stepper motor 120A for driving the first pointer 3, a second stepper motor 120B for driving the second pointer 4, and a third stepper motor 120C for driving the third pointer 5. In the following description, unless any one of the first stepper motor 120A, the second stepper motor 120B, and the third stepper motor 120C is specifically designated, each is referred to simply as a stepper motor 120.

FIG2 is a top view of a stepper motor.

As shown in FIG. 2 , the stepping motor 120 includes a stator 121 having a rotor housing hole 125 and a rotor 131 , which is magnetized to two poles in the radial direction to have magnetic polarity and is rotatably disposed in the rotor housing hole 125 .

Stator 121 includes a yoke 122 with a rotor-receiving hole 125 and a pair of outer notches 127; a core 123 joined to yoke 122; and a coil 124 wound around core 123. Yoke 122 is formed from a plate material with a high magnetic permeability, such as Permalloy. Yoke 122 has a rotor-receiving hole 125 in its center and extends in both directions in a predetermined direction X, sandwiching rotor-receiving hole 125.

The rotor receiving hole 125 is formed in the shape of a circular hole. A pair of notches 126 are formed on the inner circumferential surface of the rotor receiving hole 125. The pair of notches 126 are cut into an arc shape. The pair of notches 126 are formed at positions that are offset by 180° from each other around the center of the rotor receiving hole 125. The pair of notches 126 are formed at positions that are offset relative to the prescribed direction X around the center of the rotor receiving hole 125. In the present embodiment, the pair of notches 126 are formed at positions that are offset by, for example, approximately 135° in the forward rotation direction Dn of the rotor 131 relative to the prescribed direction X around the center of the rotor receiving hole 125. In addition, the forward rotation direction Dn of the rotor 131 is the direction in which the pointers 3 to 5 rotate clockwise. The pair of notches 126 constitute a positioning portion for determining the stop position of the rotor 131.

A pair of outer notches 127 are formed around the rotor receiving hole 125 in the yoke 122. Specifically, the pair of outer notches 127 are cut from the outer edge of the yoke 122 toward the rotor receiving hole 125 when viewed from above. The pair of outer notches 127 are cut into an arc shape. The pair of outer notches 127 are formed at positions offset by 180° from each other around the center of the rotor receiving hole 125. The pair of outer notches 127 are formed at positions offset by approximately 90° from the center of the rotor receiving hole 125 relative to the predetermined direction X.

The outer notches 127 locally narrow the area around the rotor housing hole 125 in the yoke 122. This makes the narrowed portion of the yoke 122 more susceptible to magnetic saturation, and the resulting magnetic saturation magnetically divides the area around the rotor housing hole 125 into two. The yoke 122 has a first magnetic pole portion 128 located on one side of the rotor housing hole 125 in the predetermined direction X, and a second magnetic pole portion 129 located on the other side of the rotor housing hole 125 in the predetermined direction X.

The core 123 is formed of a high-permeability material such as permalloy, and is magnetically connected to both ends of the yoke 122 .

The coil 124 is wound around the core 123 and is magnetically coupled to the first magnetic pole portion 128 and the second magnetic pole portion 129 of the yoke 122 .

When magnetic flux is generated from coil 124, the magnetic flux of stator 121 thus configured flows along core 123 and yoke 122. Furthermore, the polarity of first magnetic pole portion 128 and second magnetic pole portion 129 switches in accordance with the state of current supplied to coil 124. Stator 121 generates a magnetic field along a predetermined direction X within rotor housing hole 125.

When the magnetic pole axis of rotor 131 is perpendicular to the line connecting the pair of notches 126, the potential energy of rotor 131 reaches its lowest point, resulting in a stable stop. Hereinafter, the position where the magnetic pole axis of rotor 131 is perpendicular to the line connecting the pair of notches 126, thus stably stopping the rotor, is referred to as the stationary position. Specifically, the stationary position is a position where the magnetic pole axis of rotor 131 is offset, for example, by approximately 45° in the forward rotation direction Dn from the predetermined direction X.

As shown in FIG1 , multiple gear trains 140A, 140B, and 140C include a first gear train 140A that transmits power from a first stepping motor 120A to a first pointer 3, a second gear train 140B that transmits power from a second stepping motor 120B to a second pointer 4, and a third gear train 140C that transmits power from a third stepping motor 120C to a third pointer 5. The first gear train 140A includes at least one gear and is coupled to the rotor 131 of the first stepping motor 120A. The second gear train 140B includes at least one gear and is coupled to the rotor 131 of the second stepping motor 120B. The third gear train 140C includes at least one gear and is coupled to the rotor 131 of the third stepping motor 120C.

The drive control unit 150 is, for example, a motor driver IC (integrated circuit). The drive control unit 150 receives an indication signal output by the main control unit 60. The drive control unit 150 determines the type of the indication signal output by the main control unit 60. The drive control unit 150 generates a drive pulse for driving the stepping motor 120 based on the determination result of the indication signal. The drive control unit 150 applies the generated drive pulse to the coil 124 of the stepping motor 120 to rotate the rotor 131 forward by one step or reverse by one step. In addition, the drive control unit 150 does not have a voltage regulator. Therefore, the voltage of the drive pulse varies depending on the voltage applied from the power supply unit 10. The voltage detection unit 20 indirectly detects the voltage applied to the stepping motor 120 by detecting the power supply voltage.

Next, the driving pulse output by the driving control unit 150 will be described in detail. In the following description, it is assumed that when the driving pulse is applied to the coil 124 of the stepping motor 120, the rotor 131 is stationary at the stationary position.

The driving pulses include: a forward rotation pulse that rotates the rotor 131 180° forward at 1 Hz; a forward fast-forward pulse that rotates the rotor 131 180° forward at, for example, 64 Hz; and a reverse rotation pulse that rotates the rotor 131 180° reversely at, for example, 32 Hz.

Fig. 3 is a diagram showing an example of a forward rotation pulse according to the embodiment. Fig. 4 is an operation diagram showing the forward rotation operation of the stepping motor according to the embodiment. In Fig. 3 , the horizontal axis represents time and the vertical axis represents voltage.

As shown in Figures 3 and 4, the forward rotation pulse is a chopping pulse. The forward rotation pulse alternately repeats n times, applying voltage for an on-time A and interrupting the voltage for an off-time B. The forward rotation pulse excites the magnetic poles 128 and 129 facing the magnetic poles of the rotor 131, with a polarity opposite to that of the rotor 131.

There are multiple levels set for the forward rotation pulse. The level of the forward rotation pulse is related to the size of the pulse width of the forward rotation pulse. In addition, the pulse width of the forward rotation pulse is the total value of the conduction time in one forward rotation pulse applied when the rotor 131 rotates forward one step (the same applies to the pulse width of other pulses described below). The pulse width of the forward rotation pulse is set corresponding to the voltage detection result. For example, the correspondence between the level of the forward rotation pulse and the voltage of the voltage detection result is set so that the pulse width of the forward rotation pulse decreases as the voltage of the voltage detection result increases. The correspondence between the level of the forward rotation pulse and the voltage of the voltage detection result is stored in the storage unit 50 as a table. The correspondence between the level of the forward rotation pulse and the voltage of the voltage detection result includes a voltage amplitude that is larger than the fluctuation amplitude of the output voltage of each of the multiple power supplies that can be installed in the clock 1.

Fig. 5 is a diagram showing an example of a forward fast-forward pulse according to the embodiment. In Fig. 5 , the horizontal axis represents time, and the vertical axis represents voltage.

As shown in Figures 4 and 5, the forward fast-forward pulse consists of a first-half pulse, which constitutes the first half of the forward fast-forward pulse, and a second-half pulse, which constitutes the second half of the forward fast-forward pulse. The first-half pulse is a rectangular pulse with an on-time of C. The duty cycle of the first-half pulse is 100%. The first-half pulse excites the magnetic poles 128 and 129 facing the magnetic poles of rotor 131 with a polarity opposite to that of rotor 131. The first-half pulse causes rotor 131 to rotate forward from a stationary position. For example, the first-half pulse is applied until rotor 131 passes a position where the magnetic pole axis of rotor 131 is parallel to the line connecting the pair of notches 126. After the first-half pulse is applied, the second-half pulse is applied after an off-time of D. The second-half pulse is a chopping pulse with the same polarity as the first-half pulse but a smaller duty cycle. The second-half pulse alternates between applying voltage for an on-time of E and interrupting voltage for an off-time of F, repeating m times.

There are multiple levels of forward fast-forward pulse settings. The level of the forward fast-forward pulse is related to the size of the pulse width of the first half pulse and the pulse width of the second half pulse of the forward fast-forward pulse. Hereinafter, the pulse width of the first half pulse and the pulse width of the second half pulse of the forward fast-forward pulse are sometimes collectively referred to as the pulse width of the forward fast-forward pulse. The pulse width of the forward fast-forward pulse is set corresponding to the voltage detection result. For example, the correspondence between the level of the forward fast-forward pulse and the voltage of the voltage detection result is set so that the pulse width of each of the first half pulse and the second half pulse of the forward fast-forward pulse decreases as the voltage of the voltage detection result increases. Furthermore, the correspondence between the level of the forward fast-forward pulse and the voltage of the voltage detection result is set so that the pulse width of the entire forward fast-forward pulse decreases as the voltage of the voltage detection result increases. The correspondence between the level of the forward fast-forward pulse and the voltage of the voltage detection result is stored in the storage unit 50 as a table. Similar to the correspondence between the forward pulse level and the voltage detection result voltage, the correspondence between the forward fast-forward pulse level and the voltage detection result voltage includes a voltage range larger than the fluctuation range of the output voltage of each of the various power supplies that can be installed in the timepiece 1.

Fig. 6 is a diagram showing an example of an inversion pulse according to the embodiment. Fig. 7 to Fig. 10 are operation diagrams showing the inversion operation of the stepping motor according to the embodiment. In Fig. 6 , the horizontal axis represents time and the vertical axis represents voltage.

As shown in Figure 6, the reversal pulse includes a demagnetization pulse of the same polarity as the forward pulse, a first pulse of the same polarity as the forward pulse, a second pulse of opposite polarity to the first pulse, and a third pulse of opposite polarity to the second pulse. The demagnetization pulse is a rectangular pulse with an on-time G. The demagnetization pulse demagnetizes the residual magnetic flux in each magnetic pole portion 128, 129.

As shown in Figures 6 and 7, after the demagnetization pulse is applied, the first pulse is applied after an off-time H. The first pulse is a rectangular pulse with an on-time I. The first pulse excites the magnetic poles 128 and 129 facing the magnetic poles of rotor 131 with a polarity opposite to that of rotor 131. The first pulse causes rotor 131 to rotate forward from a stationary position. For example, the first pulse is applied just before rotor 131 reaches a point where its magnetic pole axis is parallel to the line connecting the pair of notches 127. Then, after the first pulse is removed, rotor 131 rotates forward due to inertia until the magnetic poles 128 and 129 are effectively excited by the second pulse. Thus, the rotor 131, with the help of the magnetic force based on the first pulse and the inertia after the first pulse is cut off, rotates forward, for example, to a position that passes the position where the magnetic pole axis of the rotor 131 is parallel to the line segment connecting the pair of outer notch portions 127 and does not pass the position where the magnetic pole axis of the rotor 131 is parallel to the line segment connecting the pair of notch portions 126 (for example, the position of the rotor 131 shown in Figure 8).

As shown in Figures 6 and 8, after the first pulse is applied, the second pulse is continuously applied. The second pulse is a rectangular pulse with an on-time J. The second pulse excites each magnetic pole portion 128, 129 in a manner that is opposite in polarity to that when the first pulse is applied. At the moment the second pulse is applied, the rotor 131 is in a position after forward rotation from the stationary position. Therefore, at the moment the second pulse is applied, a force in the reverse direction to return to the stationary position acts on the rotor 131. As a result, the second pulse causes the rotor 131 to reverse at an accelerated speed. For example, the second pulse is applied just before the rotor 131 reaches a position where the magnetic pole axis of the rotor 131 is parallel to the specified direction X. Then, until each magnetic pole portion 128, 129 is effectively excited by the third pulse, the rotor 131 reverses by virtue of inertia. Thus, the rotor 131 reverses to a position beyond the position where the magnetic pole axis of the rotor 131 is parallel to the specified direction X (for example, the position of the rotor 131 shown in Figure 9) by means of the force in the reversing direction to return to the stationary position, the magnetic force based on the second pulse, and the inertia after the application of the second pulse is cut off.

Furthermore, the setting of these pulses is not limited to the relationship with the rotor position as described above, as long as the reaction of the reverse vibration by the first pulse and the return by the second pulse can be utilized.

As shown in Figures 6 and 9, after the second pulse is applied, the third pulse is continuously applied. The third pulse has a first half pulse and a second half pulse. The first half pulse is a rectangular pulse with an on-time of K. The duty cycle of the first half pulse is 100%. The first half pulse excites each magnetic pole portion 128, 129 opposite to the magnetic pole of the rotor 131 in a manner opposite to the polarity of the rotor 131. The first half pulse further reverses the rotor 131, which has been reversed by the second pulse to a position beyond the position where the magnetic pole axis of the rotor 131 is parallel to the specified direction X. For example, the first half pulse is applied until the rotor 131 reaches a position beyond the position where the magnetic pole axis of the rotor 131 is parallel to the line segment connecting the pair of notches 126.

The second half pulse is a chopping pulse with the same polarity as the first half pulse and a smaller duty cycle than the first half pulse. The second half pulse is a pulse that alternately repeats the application of voltage for an on-time M and the interruption of voltage for an off-time N. After the application of the first half pulse, the second half pulse is applied after an off-time L. The second half pulse causes the rotor 131, which has reversed to a position where the magnetic pole axis of the rotor 131 is parallel to the line connecting the pair of notches 126, to reverse with lower energy than the first half pulse. The second half pulse is applied until the rotor 131 reverses to a position beyond the stationary position (see Figure 10) and the direction of rotation changes to the forward direction Dn. As shown in Figure 10, after the application of the second half pulse of the third pulse is stopped, the rotor 131 converges its vibration toward the stationary position through free vibration.

There are multiple levels of inversion pulse settings. The levels of the inversion pulse (first pulse level, third pulse level) are related to the size of the pulse width of the first pulse of the inversion pulse, the pulse width of the second pulse, the pulse width of the first half pulse of the third pulse, and the pulse width of the second half pulse of the third pulse. Hereinafter, the pulse width of the first pulse of the inversion pulse, the pulse width of the second pulse, the pulse width of the first half pulse of the third pulse, and the pulse width of the second half pulse of the third pulse are sometimes collectively referred to as the pulse width of the inversion pulse. The pulse width of the inversion pulse is set in correspondence with the voltage detection result. The correspondence between the level of the inversion pulse and the voltage of the voltage detection result is stored in the storage unit 50 as a table. Similar to the correspondence between the level of the forward pulse and the voltage of the voltage detection result, the correspondence between the level of the inversion pulse and the voltage of the voltage detection result includes a voltage amplitude that is larger than the fluctuation amplitude of the output voltage of each of the multiple power supplies that can be mounted on the clock 1. For example, assuming that the initial voltage of the lithium-ion secondary battery is 3.6V and the final voltage of the primary battery is 1.8V, the above correspondence is set to include a voltage range of 1.8V to 3.6V.

FIG. 11 is a table showing an example of the relationship among the voltage of the voltage detection result, the level of the inversion pulse, and the pulse width of the inversion pulse.

As shown in FIG11 , in this embodiment, the level of the inversion pulse is set to two levels: a high level and a low level. When the voltage detection result is 2.4V or higher and less than 3.6V, the level of the inversion pulse is set to a high level. In contrast, when the voltage detection result is 1.8V or higher and less than 2.4V, the level of the inversion pulse is set to a low level. In the high-level inversion pulse, the on-time G of the demagnetization pulse is set to 0.244ms. In the low-level inversion pulse, the on-time G of the demagnetization pulse is set to 0.488ms. That is, the pulse width of the demagnetization pulse of the inversion pulse is set so as to decrease as the voltage of the voltage detection result increases.

This demagnetization pulse is set to the same polarity as the first pulse, thereby ensuring responsiveness when the rotor starts rotating in response to the first pulse, thereby enabling more accurate reverse driving.

Furthermore, for a high-level inversion pulse, the on-time I of the first pulse is set to 0.977 ms. For a low-level inversion pulse, the on-time I of the first pulse is set to 1.343 ms. Specifically, the correspondence between the inversion pulse level and the voltage detected is set so that the pulse width of the first pulse of the inversion pulse decreases as the voltage detected increases. Furthermore, the off-time H between the demagnetization pulse and the first pulse is set to 5.127 ms for a high level and 5.371 ms for a low level. Furthermore, the on-time J of the second pulse of the inversion pulse is set to 2.197 ms, regardless of the inversion pulse level.

Furthermore, in the high-level inversion pulse, the on-time K of the first half of the third pulse is set to 3.662 ms. In the low-level inversion pulse, the on-time K of the first half of the third pulse is set to 11.230 ms. Specifically, the correspondence between the inversion pulse level and the voltage detected is set so that the pulse width of the first half of the third pulse decreases as the voltage detected increases.

Furthermore, in the high-level inversion pulse, the on-time M of the second half of the third pulse is set to 0.488 ms, the off-time N is set to 0.488 ms, and the number of voltage applications, l, is set to 12. In the low-level inversion pulse, the on-time M of the second half of the third pulse is set to 0.488 ms, the off-time N is set to 0.488 ms, and the number of voltage applications, l, is set to 4. In other words, the correspondence between the level of the inversion pulse and the voltage of the voltage detection result is set so that the pulse width of the second half of the third pulse of the inversion pulse increases as the voltage of the voltage detection result increases. Furthermore, the correspondence between the level of the inversion pulse and the voltage of the voltage detection result is set so that the overall pulse width of the third pulse of the inversion pulse decreases as the voltage of the voltage detection result increases. Furthermore, the off-time L between the first and second half pulses is set to 0.488 ms, regardless of the level of the inversion pulse.

Next, a method for controlling the timepiece 1 will be described.

Fig. 12 is a flowchart of the processing of the timepiece according to the embodiment. The following processing flow is executed at regular time intervals.

12 , when the stepping motor 120 is driven in one step, the voltage detection step S10 is first performed. In the voltage detection step S10 , the main control unit 60 obtains the voltage detection result output by the voltage detection unit 20 .

Next, the process of the drive instruction output step S20 is performed. In the drive instruction output step S20, the main control unit 60 outputs an instruction signal for driving the motor unit 100 to the drive control unit 150. The instruction signal is defined corresponding to the type of drive of the motor unit 100 (forward drive, forward fast forward drive, or reverse drive) and the pulse level. The main control unit 60 refers to the correspondence between the pulse level and the voltage of the voltage detection result stored in the storage unit 50 and outputs an instruction signal corresponding to the pulse level based on the voltage detection result.

Next, the process of the drive pulse selection step S30 is performed. In the drive pulse selection step S30, the drive control unit 150 determines the type of the instruction signal output by the main control unit 60 and generates a drive pulse based on the instruction signal.

Next, the process of the drive pulse output step S40 (reverse rotation step) is performed. The drive control unit 150 outputs the drive pulse generated in the drive pulse selection step S30 and applies the drive pulse to the coil 124 of the stepping motor 120. As a result, the drive control unit 150 rotates the rotor 131 using the forward rotation pulse, forward fast forward pulse, or reverse rotation pulse having a pulse width set according to the voltage detection result.

Hereinafter, the effects of this embodiment will be described.

Figure 13 is a graph showing the relationship between the pulse width of each of the first and third inversion pulses and the voltage range capable of driving the stepping motor. In Figure 13, the horizontal axis represents the pulse width, and the vertical axis represents the voltage (driving voltage) applied to the coil 124 of the stepping motor 120.

As shown in FIG13 , the first and third pulses of the inversion pulse each have a voltage range within which rotor 131 can rotate accurately. The voltage range within which rotor 131 can rotate accurately is determined by the pulse widths of the first and third pulses of the inversion pulse. If the voltage of the first or third pulse of the inversion pulse deviates from the voltage range shown in FIG13 , rotor 131 will not be able to reverse even one step, causing stepping motor 120 to lose step.

Here, the desynchronization during reverse driving of the stepping motor 120 will be described in detail.

If a voltage exceeding the upper limit of the voltage range associated with the first pulse is applied to coil 124 during the first reverse pulse, rotor 131 will rotate forward until it passes the position where the magnetic pole axis of rotor 131 is parallel to the line segment connecting the pair of notches 126. Consequently, when a second pulse is applied to coil 124, rotor 131 may not be reversed to the desired position. Furthermore, if a voltage below the lower limit of the voltage range associated with the first pulse is applied to coil 124 during the first reverse pulse, the amount of forward rotation of rotor 131 due to the first pulse is insufficient. Consequently, the force required to return rotor 131 to its stationary position is insufficient, and when a second pulse is applied to coil 124, rotor 131 may not be reversed to the desired position. Thus, if a voltage within the voltage range determined by the pulse width of the first pulse is not applied to coil 124 during the first reverse pulse, stepping motor 120 may lose step.

Furthermore, if a voltage exceeding the upper limit of the voltage range associated with the third pulse is applied to coil 124 during the application of the third pulse of the reversal pulse, rotor 131 passes the stationary position and reverses to a position beyond the position where the magnetic pole axis of rotor 131 is parallel to the line connecting the pair of notches 126. Thus, when the third pulse is applied to coil 124, rotor 131 may reverse two steps (360°). Furthermore, if a voltage below the lower limit of the voltage range associated with the third pulse is applied to coil 124 during the application of the third pulse of the reversal pulse, insufficient energy is available to move rotor 131 between magnetic poles 128 and 129, preventing rotor 131 from reversing to a position beyond the position where the magnetic pole axis of rotor 131 is parallel to the line connecting the pair of notches 126. As described above, when applying the reverse pulse to the coil 124 , if the third pulse cannot be applied at a voltage within the voltage range determined by the pulse width of the third pulse, the stepping motor 120 may lose step.

In this embodiment, the drive control unit 150 controls the rotor 131 to reversely rotate using a third pulse having a pulse width set according to the voltage detection result. This prevents the stepping motor 120 from being out of sync with the third pulse, and allows the rotor 131 to be accurately reversed at various voltages without detecting the rotational position of the rotor 131. Consequently, even if the voltage applied to the coil 124 of the stepping motor 120 varies, the accuracy of the rotor 131's reverse rotation can be maintained.

Furthermore, the timepiece 1 includes a storage unit 50 that stores a correspondence between a plurality of levels related to the pulse width of the third pulse and the voltage detection result; and a main control unit 60 that instructs the drive control unit 150 to reversely rotate the rotor 131 using the third pulse having a pulse width set in accordance with the voltage detection result based on the correspondence between the level of the inversion pulse and the voltage detected. Thus, the timepiece 1 can autonomously and accurately reverse the rotor 131 in accordance with the voltage detection result without requiring instructions from an external device.

Furthermore, the timepiece 1 is configured to be capable of incorporating two or more power sources having output voltages in different voltage ranges. The memory unit 50 stores a correspondence between the pulse width of a third pulse having a voltage amplitude greater than the fluctuation amplitude of the output voltages of the two or more power sources and the voltage detected. Thus, compared to a timepiece driven by only a single power source, even when the voltage range applied to the coil 124 of the stepping motor 120 is wider, the correspondence between the pulse width of the third pulse and the voltage detected, stored in the memory unit 50, can be used to accurately reverse the rotor 131.

Furthermore, the correspondence between the level of the reverse pulse and the voltage detected is set so that the pulse width of the third pulse decreases as the voltage detected increases. This prevents the energy supplied to stepper motor 120 from increasing as the voltage detected increases. This balances the suppression of imbalances caused by both excessive energy due to the high-voltage third pulse and insufficient energy due to the low-voltage third pulse. Consequently, rotor 131 can be accurately reversed.

Furthermore, the main control unit 60 instructs the drive control unit 150 to reverse the rotor 131 using the first pulse having a pulse width set in accordance with the voltage detection result based on the correspondence between the level of the reverse pulse and the voltage detected. This suppresses the detuning of the stepping motor 120 caused by the third pulse and also suppresses the detuning of the stepping motor 120 caused by the first pulse, allowing the rotor 131 to be accurately reversed at various voltages. Consequently, even if the voltage applied to the coil 124 of the stepping motor 120 varies, the accuracy of the reverse rotation of the rotor 131 can be maintained.

Furthermore, the correspondence between the level of the reverse pulse and the voltage detected is set so that the pulse width of the first pulse decreases as the voltage detected increases. This prevents the energy supplied to stepper motor 120 from increasing as the voltage detected increases. This balances the suppression of imbalances caused by both excessive energy due to the high-voltage first pulse and insufficient energy due to the low-voltage first pulse. Consequently, rotor 131 can be accurately reversed.

Furthermore, the third inversion pulse includes a second half pulse, which constitutes the second half of the third pulse and is a chopping pulse with a smaller duty cycle than the first half pulse. This reduces the rotational speed of rotor 131 during the second half of the third pulse application compared to a case where the entire third pulse is a rectangular pulse with a 100% duty cycle. This prevents excessive energy imbalance caused by the high-voltage third pulse.

Furthermore, the first half of the third inversion pulse is a rectangular pulse with a 100% duty cycle. Therefore, compared to a case where the entire third inversion pulse is a chopped pulse, the energy supplied to rotor 131 can be increased. This prevents imbalances caused by insufficient energy due to the low-voltage third pulse. Consequently, even when the second half of the third inversion pulse is a chopped pulse, rotor 131 can be accurately reversed.

Furthermore, if the application of the second half of the third pulse is stopped while the rotor 131 is rotating in the reverse direction due to the third pulse, the rotor 131 may pass through the stationary position and reverse due to inertia to a position where the magnetic pole axis of the rotor 131 crosses the line segment connecting the pair of notches 126, potentially causing a misalignment. In this embodiment, the drive control unit 150 reverses the rotor 131 to a position where it passes through the stationary position when applying the reverse pulse to the coil 124. The second half of the third pulse is then applied until the rotor 131's rotational direction changes to the forward direction Dn. This prevents the rotor 131 from reversed due to inertia to a position where the magnetic pole axis of the rotor 131 crosses the line segment connecting the pair of notches 126, allowing the rotor 131 to move toward the stationary position. Consequently, the rotor 131 can be accurately reversed.

Furthermore, the timepiece 1 includes a support body 110 on which a drive control unit 150 is provided, and the main control unit 60 is provided separately from the support body 110 (e.g., on the bottom plate of the timepiece 1). Thus, the motor unit 100 including the support body 110 can be configured separately from the timepiece body on which the main control unit 60 is provided. Therefore, when the motor unit 100 is mounted as an intermediate product on a finished timepiece body, the stepping motor 120 of the motor unit 100 can be driven in reverse regardless of the type of power supply provided in the timepiece body to which the motor unit 100 is mounted. Therefore, the structure and control method of this embodiment are suitable for a timepiece 1 equipped with a motor unit 100 including the support body 110.

In addition, the present invention is not limited to the above-mentioned embodiment described with reference to the drawings, and various modifications are conceivable within the technical scope of the present invention.

For example, in the above embodiment, the timepiece 1 is equipped with a power supply unit 10 that can handle two or more power sources, but the present invention is not limited to this. The structure and control method of the above embodiment can realize reverse driving of the stepping motor with various power supply voltages. Therefore, for example, a power supply unit that can only handle one power source can also be installed.

Furthermore, in the above-described embodiment, the voltage detection unit 20 and the storage unit 50 are disposed outside the motor unit 100, but the present invention is not limited thereto. For example, the voltage detection unit and the storage unit may also be disposed on the support body of the motor unit. In this case, for example, it may also be configured such that the main control unit instructs the drive control unit on the type of drive, and the drive control unit determines the level of each pulse based on the voltage detection result. According to this structure, in addition to the effects of the above-described embodiment, it is also possible to further achieve the effect of simplifying the processing performed in the main control unit disposed in the watch body. Therefore, it is more effective when the motor unit is mounted as an intermediate product on the finished watch body.

In the above embodiment, the drive control unit 150 outputs a drive pulse, but the present invention is not limited thereto. For example, the main control unit may have the functions of the drive control unit 150 in the above embodiment and output a drive pulse.

In the above embodiment, the voltage detector 20 indirectly detects the voltage applied to the stepping motor 120 by detecting the power supply voltage, but the present invention is not limited thereto. The voltage detector may also directly detect the voltage applied to the stepping motor 120 .

Furthermore, in the above embodiment, the first half of the third inversion pulse is a rectangular pulse with a duty cycle of 100%, but the present invention is not limited thereto. The first half of the third inversion pulse may also be a chopped pulse. Even in this case, the above-described effects can be achieved by setting the duty cycle of the first half of the pulse to be greater than the duty cycle of the second half of the pulse.

Furthermore, in the above-described embodiment, two levels, a high level and a low level, are set as the level of each pulse, but three or more levels may be set.

Furthermore, in the above embodiment, the main control unit 60 determines the level of each pulse based on the correspondence between the level of each pulse and the voltage detected by the voltage detection result stored in the storage unit 50, but the present invention is not limited to this. For example, the main control unit may calculate the level of each pulse based on the voltage detected by the voltage detection result using a predetermined formula.

In the above embodiment, the levels of the first, second, and third pulses in the inversion pulses are collectively set to the inversion pulse level, but the present invention is not limited thereto. For example, the levels of the first, second, and third pulses may be set separately.

Furthermore, in the above embodiment, the timepiece 1 includes the motor unit 100 , but the present invention is not limited thereto and the stepping motor and the train wheel may be directly provided on the bottom plate of the timepiece without a support.

Furthermore, the components in the above-described embodiments can be appropriately replaced with well-known components without departing from the spirit of the present invention.

Claims (10)

1. A clock, the clock having: A voltage detection unit detects the voltage applied to the stepper motor that drives the pointer, and outputs the voltage detection result; and The first control unit is a control unit that reverses the rotor of the stepper motor using a reversing pulse. The reversing pulse includes a first pulse of the same polarity as the forward rotation pulse that causes the rotor to rotate forward, a second pulse of the opposite polarity to the first pulse, and a third pulse of the opposite polarity to the second pulse. The first control unit controls the rotor to reverse using the third pulse, whose pulse width is set corresponding to the voltage detection result. The third pulse has the following characteristics: The first half of the pulse, which constitutes the first half of the third pulse; and The second half pulse constitutes the second half of the third pulse and is a chopping pulse with a duty cycle smaller than that of the first half pulse. 2. The clock according to claim 1, wherein the clock comprises: A storage unit stores a correspondence between multiple third pulse levels and the voltage of the voltage detection result, wherein the multiple third pulse levels are related to the pulse width of the third pulse; and The second control unit instructs the first control unit to reverse the rotor using the third pulse, wherein the pulse width of the third pulse is set according to the correspondence between the third pulse level and the voltage of the voltage detection result, corresponding to the voltage detection result. 3. The clock according to claim 2, wherein, The clock is designed to be compatible with two or more power sources with different output voltage ranges. The storage unit stores the correspondence between the third pulse level and the voltage of the voltage detection result, wherein the third pulse level includes a voltage amplitude that is larger than the variation amplitude of the output voltage of each of the two or more power supplies. 4. The clock according to claim 2 or 3, wherein, The correspondence between the third pulse level and the voltage of the voltage detection result is set such that the pulse width of the third pulse decreases as the voltage of the voltage detection result increases. 5. The clock according to claim 2, wherein, The storage unit also stores a plurality of correspondences between first pulse levels and the voltage of the voltage detection result, wherein the plurality of first pulse levels are related to the pulse width of the first pulse. The second control unit instructs the first control unit to reverse the rotor using the third pulse and the first pulse, wherein the pulse width of the third pulse is set according to the correspondence between the first pulse level and the voltage of the voltage detection result, and the pulse width of the first pulse is set according to the voltage detection result. 6. The clock according to claim 5, wherein, The correspondence between the third pulse level and the voltage of the voltage detection result is set such that the pulse width of the third pulse decreases as the voltage of the voltage detection result increases. The correspondence between the first pulse level and the voltage of the voltage detection result is set such that the pulse width of the first pulse decreases as the voltage of the voltage detection result increases. 7. The clock according to claim 2, wherein, The clock has a support body, and the first control unit is disposed on the support body. The second control unit is separately disposed from the support body. 8. The clock according to claim 1, wherein, Before applying the first pulse to the stepper motor, the first control unit applies a demagnetizing pulse of the same polarity as the first pulse to the stepper motor. 9. An electronic device comprising a clock as described in any one of claims 1 to 8. 10. A method for controlling a clock, comprising the following steps: The voltage detection step involves the voltage detection unit detecting the voltage applied to the stepper motor that drives the pointer, and outputting the voltage detection result; and In the reversal step, the first control unit uses a reversal pulse to reverse the rotor of the stepper motor. This reversal pulse includes a first pulse of the same polarity as the forward rotation pulse that causes the rotor to rotate forward, a second pulse of the opposite polarity, and a third pulse of the opposite polarity. In this reversal step, the rotor is reversed using the third pulse, whose pulse width is set corresponding to the voltage detection result. The third pulse has the following characteristics: The first half of the pulse, which constitutes the first half of the third pulse; and The second half pulse constitutes the second half of the third pulse and is a chopping pulse with a duty cycle smaller than that of the first half pulse.