JP7709350B2 - Stepping motor control device, movement, timepiece, and stepping motor control method - Google Patents

Description

The present invention relates to a stepping motor control device, a movement, a timepiece, and a stepping motor control method.

Conventionally, there have been methods for detecting the position of the hands of a watch. For example, a technology has been proposed in which a stepping motor is driven by a drive pulse during normal operation, and the rotation state of the rotor is detected by the induced voltage (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 62-291591

According to conventional technology such as that described in Patent Document 1, in order to detect the rotation state of the rotor, after applying a normal drive pulse to the stepping motor, it is necessary for the rotor to vibrate at a certain speed or higher and generate an induced voltage equal to or higher than a predetermined threshold voltage. However, there is a problem in that, depending on the motor, it is difficult to generate an induced voltage, making it difficult to detect the rotation state.

The present invention was made in consideration of these circumstances, and aims to detect the position of the pointer.

A stepping motor control device according to one embodiment of the present invention comprises a drive unit that drives a stepping motor having a rotor that rotates a pointer and a coil that generates a magnetic flux to rotate the rotor, a control unit that outputs a drive pulse for rotating the rotor and a swing pulse for swinging the rotor to the drive unit, a voltage detection unit that detects an induced voltage generated in the coil when the rotor vibrates, and a judgment unit that judges the mechanical load received by the rotor based on the result detected by the voltage detection unit , wherein the control unit outputs a corresponding swing pulse before outputting the drive pulse, and the judgment unit judges the mechanical load based on the result of detecting the rotation associated with the output of the swing pulse .

In a stepping motor control device according to one aspect of the present invention, the control unit outputs the drive pulse after a predetermined period of time has elapsed after outputting the oscillation pulse.

In a stepping motor control device according to one aspect of the present invention, the determination unit determines whether a first gear, which rotates based on the rotation of the rotor, is in contact with a load tooth of a second gear having load teeth, as the mechanical load.

In a stepping motor control device according to one aspect of the present invention, the control unit controls the energy for driving the stepping motor in accordance with the mechanical load determined by the determination unit.

In a stepping motor control device according to one aspect of the present invention, the control unit controls the energy for driving the stepping motor by controlling the output time of the drive pulse.

In a stepping motor control device according to one aspect of the present invention, the control unit controls the energy used to drive the stepping motor by controlling the excitation method of the stepping motor.

In a stepping motor control device according to one aspect of the present invention, the control unit controls the energy for driving the stepping motor by controlling the duty ratio of the drive pulse.

In a stepping motor control device according to one aspect of the present invention, the control unit controls the energy for driving the stepping motor by controlling the voltage of the drive pulse.

In a stepping motor control device according to one aspect of the present invention, the oscillation pulse is either a first oscillation pulse having energy for rotating the rotor in a first rotation direction and for oscillating the rotor, or a second oscillation pulse having energy for rotating the rotor in a second rotation direction after outputting the first oscillation pulse and for oscillating the rotor.

In addition, in a stepping motor control device according to one aspect of the present invention, the first rotation direction is a forward rotation direction, and the second rotation direction is a direction opposite to the first rotation direction.

In addition, in a stepping motor control device according to one aspect of the present invention, the control unit outputs the first oscillation pulse when the oscillation pulse is output in accordance with a predetermined cycle in which the drive pulse is output, and outputs the first oscillation pulse and the second oscillation pulse when the oscillation pulse is output at a predetermined timing that does not correspond to the predetermined cycle in which the drive pulse is output.

In a stepping motor control device according to one aspect of the present invention, the determination unit determines the mechanical load received by the rotor based on whether the voltage value detected by the voltage detection unit exceeds a predetermined threshold value.

In a stepping motor control device according to one aspect of the present invention, the determination unit determines the mechanical load received by the rotor based on whether the timing of occurrence of the voltage value detected by the voltage detection unit is within a predetermined period.

In a stepping motor control device according to one aspect of the present invention, the control unit has a swing pulse output mode in which the swing pulse is output, and a swing pulse non-output mode in which the swing pulse is not output.

In a stepping motor control device according to one aspect of the present invention, the drive unit drives the stepping motor with a first voltage when the drive pulse is output from the control unit, and drives the stepping motor with a second voltage lower than the first voltage when the oscillation pulse is output from the control unit.

In addition, in a stepping motor control device according to one aspect of the present invention, when the mechanical load received by the rotor as determined by the determination unit is smaller than a predetermined threshold value, the control unit applies a drive pulse of a higher rank than the drive pulse applied immediately before from among the drive pulses of multiple ranks having different energies, and when the mechanical load received by the rotor as determined by the determination unit is greater than the predetermined threshold value a predetermined number of times in succession, the control unit applies a drive pulse of a lower rank than the drive pulse applied immediately before from among the drive pulses of multiple ranks having different energies.

In a stepping motor control device according to one aspect of the present invention, the control unit selects which rank of the oscillation pulse to apply from among a plurality of ranks of the oscillation pulses with different energy levels, based on the number of times that the determination unit determines that the mechanical load received by the rotor is greater than a predetermined threshold value when a gear having loaded teeth makes one revolution.

In addition, in a stepping motor control device according to one aspect of the present invention, the control unit does not control the drive pulse while controlling the rank of the oscillation pulse.

A movement according to one aspect of the present invention includes the stepping motor control device described above and the stepping motor.

A watch according to one aspect of the present invention is equipped with the movement described above.

A stepping motor control method according to one embodiment of the present invention includes a stepping motor having a rotor that rotates a pointer and a coil that generates a magnetic flux to rotate the rotor, and the stepping motor is configured to rotate the rotor by applying a drive pulse to the stepping motor, and the rotor is oscillated by applying an oscillation pulse to the stepping motor, detect an induced voltage generated in the coil when the rotor vibrates, determine a mechanical load received by the rotor based on the detected result, output a corresponding oscillation pulse before outputting the drive pulse, and determine the mechanical load based on a result detected by the voltage detection unit of the rotation resulting from the output of the oscillation pulse.

The present invention makes it possible to detect the position of the pointer.

1 is an external view of a timepiece according to a first embodiment. FIG. FIG. 2 is a plan view of the front side of the movement according to the first embodiment. FIG. 2 is a plan view of the back side of the movement according to the first embodiment. FIG. 2 is a plan view showing a part of the movement according to the first embodiment, in which the first wheel train group is seen from the front side. FIG. 4 is a plan view of the 24-hour gear according to the first embodiment. FIG. 2 is a diagram illustrating an example of a functional configuration of a timepiece according to a first embodiment. 3 is a diagram showing an example of the configuration of a pointer drive unit according to the first embodiment; FIG. 5A and 5B are diagrams illustrating an example of a rocking pulse and a driving pulse in the first embodiment. 5A and 5B are diagrams illustrating an example of vibration when a load tooth and a pinion mesh with each other in the first embodiment and a vibration when a standard tooth and a pinion mesh with each other. 4 is a flowchart showing an example of an operation of the stepping motor control device in the first embodiment. FIG. 11 is a plan view of the front side of the movement in the second embodiment. FIG. 11 is a diagram illustrating an example of the configuration of a pointer drive unit in a second embodiment. 13A and 13B are diagrams illustrating an example of a rocking pulse and a driving pulse in the second embodiment. 13A and 13B are diagrams illustrating modified examples of a rocking pulse and a driving pulse in the second embodiment. 13A and 13B are diagrams illustrating an example of a case in which the energy for driving a stepping motor is controlled by controlling the output time of a drive pulse in the third embodiment. 13 is a diagram showing an example of a case where the energy for driving the stepping motor is controlled by controlling the excitation method of the stepping motor in the third embodiment. FIG. 13A and 13B are diagrams illustrating an example of a case in which the energy for driving a stepping motor is controlled by controlling the duty ratio of a drive pulse in the third embodiment. 13A and 13B are diagrams illustrating an example of a case in which the energy for driving a stepping motor is controlled by controlling the voltage of a drive pulse in the third embodiment. 13A and 13B are diagrams illustrating an example of a rocking pulse and a driving pulse in the fourth embodiment. 13 is a diagram showing whether or not an induced voltage is detected when the voltages of the drive pulse and the oscillation pulse are changed in the fifth embodiment. FIG. 13A to 13C are diagrams illustrating drive pulse rank control in the sixth embodiment. 23A to 23C are diagrams illustrating oscillation pulse rank control in the seventh embodiment. 13A to 13C are diagrams illustrating an example of a case where the drive pulse rank control and the oscillation pulse control in the eighth embodiment are combined.

The following describes an embodiment of the present invention with reference to the drawings. In the following description, components having the same or similar functions are given the same reference numerals. Furthermore, duplicate descriptions of those components may be omitted.

[First embodiment]
Generally, the mechanical body that includes the driving parts of a watch is called the "movement". When the dial and hands are attached to this movement and it is placed inside a watch case to complete the product, the watch is called "complete". Of the two sides of the base plate that constitutes the base of the watch, the side where the glass of the watch case is located (i.e. the side where the dial is located) is called the "back side" of the movement. Also, of the two sides of the base plate, the side where the case back of the watch case is located (i.e. the side opposite the dial) is called the "front side" of the movement.

FIG. 1 is an external view of a timepiece according to a first embodiment.
As shown in Fig. 1, the complete timepiece 1 of this embodiment is equipped with a movement 4 (timepiece movement), a dial 5 with a scale, an hour hand 6 (hand), a minute hand 7, a second hand 8, and a 24-hour hand 9, all housed within a watch case 2 consisting of a case back cover and a glass 3 (not shown). The dial 5 has a date window 5a that displays a date character 46a displayed on a date wheel 46 (described later). This makes it possible to check the date in addition to the time on the watch 1.

Fig. 2 is a plan view of the front side of the movement according to the first embodiment. Fig. 3 is a plan view of the back side of the movement according to the first embodiment.
2 and 3, the movement 4 includes a main plate 11, a date indicator holder 13, a first motor 20A, a second motor 20B, a first gear train group 30, and a second gear train group 50. The main plate 11 constitutes the base plate of the movement 4. The date indicator holder 13 is disposed on the back side of the main plate 11.

As shown in FIG. 2, the first motor 20A and the second motor 20B are stepping motors each having a stator 21 and a rotor 22. Each of the first motor 20A and the second motor 20B rotates the rotor 22 180° in one step. The first motor 20A generates power to rotate the hour hand 6, the 24-hour hand 9, and the date wheel 46 (all see FIG. 1). The second motor 20B generates power to rotate the minute hand 7 and the second hand 8 (all see FIG. 1). A pinion is formed on the rotor 22 of each of the first motor 20A and the second motor 20B.

FIG. 4 is a plan view showing a part of the movement according to the first embodiment, in which the first wheel train group is seen from the front side.
3 and 4, the first wheel train group 30 has gears that rotate based on the rotation of the rotor 22 of the first motor 20A. The first wheel train group 30 includes an hour wheel train 31 that transmits the rotation of the rotor 22 of the first motor 20A to the hour hand 6, and a calendar wheel train 41 that transmits the rotation of the rotor 22 of the first motor 20A to the 24-hour hand 9 (see FIG. 1) and a date indicator 46.

As shown in FIG. 4 , the hour wheel train 31 has a first hour intermediate wheel 32 , a second hour intermediate wheel 33 , a third hour intermediate wheel 34 , and a hour wheel 35 .
The first hour intermediate wheel 32 is rotatably supported by the main plate 11 (see FIG. 2). The first hour intermediate wheel 32 has a first hour intermediate gear 32a and a first hour intermediate pinion 32b. The first hour intermediate gear 32a meshes with the pinion of the rotor 22 of the first motor 20A. The first hour intermediate wheel 32 rotates at a reduction ratio of 6 relative to the rotor 22. In other words, the first hour intermediate wheel 32 rotates once every six rotations of the rotor 22 of the first motor 20A.

The second hour intermediate wheel 33 is rotatably supported by the main plate 11. The second hour intermediate wheel 33 has a second hour intermediate gear 33a and a second hour intermediate pinion 33b. The second hour intermediate gear 33a meshes with the first hour intermediate pinion 32b of the first hour intermediate wheel 32. The second hour intermediate wheel 33 is a driven gear for the first hour intermediate wheel 32. The second hour intermediate wheel 33 rotates with a reduction ratio of 7.5 relative to the first hour intermediate wheel 32. In other words, the second hour intermediate wheel 33 rotates with a reduction ratio of 45 relative to the rotor 22 of the first motor 20A.

The third hour intermediate wheel 34 is rotatably supported by the main plate 11. The third hour intermediate wheel 34 has a third hour intermediate gear 34a and a third hour intermediate pinion 34b (first gear). The third hour intermediate gear 34a meshes with the second hour intermediate pinion 33b of the second hour intermediate wheel 33. The third hour intermediate wheel 34 is a driven gear for the second hour intermediate wheel 33. The third hour intermediate wheel 34 rotates with a reduction ratio of 8 relative to the second hour intermediate wheel 33. In other words, the third hour intermediate wheel 34 rotates with a reduction ratio of 360 relative to the rotor 22 of the first motor 20A.

The hour wheel 35 is rotatably inserted on a central pipe (not shown) held by the main plate 11. The hour wheel 35 is held by the date dial holder 13 (see FIG. 3) from the back side via a hand seat. The back end of the hour wheel 35 protrudes from the date dial holder 13 to the back side. The hour hand 6 (see FIG. 1) is attached to the back end of the hour wheel 35. The hour wheel 35 has a barrel gear 35a. The barrel gear 35a meshes with the third hour intermediate gear 34a of the third hour intermediate wheel 34. The hour wheel 35 is a driven gear for the third hour intermediate wheel 34. The hour wheel 35 rotates with a reduction ratio of 1 relative to the third hour intermediate wheel 34. In other words, the hour wheel 35 rotates with a reduction ratio of 360 relative to the rotor 22 of the first motor 20A.

The calendar train wheel 41 includes the above-mentioned first hour intermediate wheel 32 , second hour intermediate wheel 33 , and third hour intermediate wheel 34 , as well as a 24-hour wheel 42 and a date-turning intermediate wheel 43 .
The 24-hour wheel 42 is rotatably supported by the main plate 11. The shaft portion of the 24-hour wheel 42 protrudes from the date wheel holder 13 to the rear side. The 24-hour hand 9 (see FIG. 1) is attached to the rear end of the shaft portion. The 24-hour wheel 42 has a 24-hour gear 42a (second gear). The 24-hour gear 42a meshes with the third hour intermediate pinion 34b of the third hour intermediate wheel 34. The 24-hour wheel 42 is a driven gear for the third hour intermediate wheel 34. The 24-hour wheel 42 rotates with a reduction ratio of 2 relative to the third hour intermediate wheel 34. In other words, the 24-hour wheel 42 rotates with a reduction ratio of 720 relative to the rotor 22 of the first motor 20A.

The intermediate date wheel 43 is rotatably supported by the main plate 11. The center of rotation of the intermediate date wheel 43 is located around the center of rotation of the 24-hour wheel 42 at a position offset from the center of rotation of the third intermediate date wheel 34 by an angle of less than 180°. In other words, the center of rotation of the intermediate date wheel 43 is located at a position that is off the straight line passing through the center of rotation of the 24-hour wheel 42 and the center of rotation of the third intermediate date wheel 34 in a plan view. The intermediate date wheel 43 has an intermediate date gear 43a and a disk wheel 43b. The intermediate date gear 43a is engaged with the 24-hour intermediate gear 42a. The intermediate date wheel 43 is a driven wheel for the 24-hour wheel 42. The intermediate date wheel 43 rotates with respect to the 24-hour wheel 42 at a reduction ratio of 1. In other words, the intermediate date wheel 43 rotates with respect to the rotor 22 of the first motor 20A at a reduction ratio of 720. The disc wheel 43b overlaps with the intermediate date gear 43a. The disc wheel 43b is equipped with a feed tooth 43c. The feed tooth 43c protrudes radially outward from the outer circumferential surface of the disc wheel 43b.

The date driving wheel 44 is rotatably supported on the main plate 11. The date driving wheel 44 has a date driving gear 44a. The date driving gear 44a is formed so that it can mesh with the feed tooth 43c of the intermediate date driving wheel 43. The date driving wheel 44 rotates when the feed tooth 43c of the intermediate date driving wheel 43 enters the rotation trajectory of the date driving gear 44a and meshes with it. Therefore, the date driving wheel 44 rotates intermittently due to the rotation of the intermediate date driving wheel 43. The date driving wheel 44 rotates the date wheel 46.

The date wheel 46 is a ring-shaped member rotatably attached to the main plate 11. The date wheel 46 is held down from the back side by the date wheel holder 13 (see FIG. 3). The date characters 46a (see FIG. 1), which are date information, are displayed along the circumferential direction on the back side of the date wheel 46. The date wheel 46 displays the date information by exposing the date characters 46a through the date window 5a of the dial 5. A plurality of internal teeth 46b are formed around the entire inner peripheral edge of the date wheel 46. The internal teeth 46b are engaged with the date driving gear 44a. The date wheel 46 rotates in conjunction with the rotation of the date driving wheel 44. Therefore, the date wheel 46 rotates intermittently with the rotation of the intermediate date driving wheel 43. The position of the date wheel 46 in the rotation direction is regulated by the jumper 47. The jumper 47 restricts the rotation of the date wheel 46 by engaging the claw at the tip with the internal teeth 46b of the date wheel 46.

As shown in FIG. 2, the second wheel train group 50 has gears that rotate based on the rotation of the rotor 22 of the second motor 20B. The second wheel train group 50 includes a front wheel train 51 that transmits the rotation of the rotor 22 of the second motor 20B to the second hand 8 and minute hand 7 (both see FIG. 1). The front wheel train 51 includes a fourth intermediate wheel 52, a fourth wheel 53, a third wheel 54, and a second wheel 55.

The fourth intermediate wheel 52 is rotatably supported on the base plate 11. The fourth intermediate wheel 52 has a fourth intermediate gear 52a and a fourth intermediate pinion 52b. The fourth intermediate gear 52a meshes with the pinion of the rotor 22 of the second motor 20B. The fourth intermediate wheel 52 rotates with a reduction ratio of 6 relative to the rotor 22 of the second motor 20B.

The fourth wheel 53 is arranged rotatably relative to the main plate 11. The fourth wheel 53 has a fourth arbor (not shown), a fourth gear 53b assembled to the fourth arbor, and a fourth pinion (not shown) formed on the fourth arbor. The fourth arbor is inserted inside the second arbor, which will be described later. The back end of the fourth arbor is attached to the second hand 8 (see FIG. 1). The fourth gear 53b meshes with the fourth intermediate pinion 52b. The fourth wheel 53 is a driven gear for the fourth intermediate wheel 52. The fourth wheel 53 rotates with a reduction ratio of 10 relative to the fourth intermediate wheel 52. In other words, the fourth wheel 53 rotates with a reduction ratio of 60 relative to the rotor 22 of the second motor 20B.

The third wheel 54 is rotatably supported by the main plate 11. The third wheel 54 includes a third gear 54a and a third pinion (not shown). The third gear 54a meshes with the fourth pinion. The third wheel 54 is a driven gear for the fourth wheel 53. The third wheel 54 rotates with respect to the fourth wheel 53 at a reduction ratio of 20. In other words, the third wheel 54 rotates with respect to the rotor 22 of the second motor 20B at a reduction ratio of 400.

The center wheel 55 is rotatably supported by a central pipe (not shown). The center wheel 55 has a center arbor (not shown) and a center gear 55b assembled to the center arbor. The center arbor is formed in a cylindrical shape and is inserted inside the central pipe. The minute hand 7 (see FIG. 1) is attached to the rear end of the center arbor. The center gear 55b meshes with the third pinion. The center wheel 55 is a driven gear for the third wheel 54. The center wheel 55 rotates with a reduction ratio of 9 relative to the third wheel 54. In other words, the center wheel 55 rotates with a reduction ratio of 3600 relative to the rotor 22 of the second motor 20B.

FIG. 5 is a plan view of the 24-hour gear according to the first embodiment.
As shown in FIG. 5, the 24-hour gear 42a has a plurality of teeth 60 and an elastic portion 65. The plurality of teeth 60 includes a standard tooth 61 and a first loaded tooth 62A as a loaded tooth 62. The standard tooth 61 is all teeth of the plurality of teeth 60 except the first loaded tooth 62A. The standard tooth 61 is a tooth of a general gear, and is a tooth formed in a circular tooth shape, an involute tooth shape, a cycloid tooth shape, or the like. The first loaded tooth 62A is one tooth of the plurality of teeth 60 of the 24-hour gear 42a. The first loaded tooth 62A is arranged on one side of the outer circumference of the 24-hour gear 42a so as not to come into contact with the third hour intermediate pinion 34b at equal intervals when the 24-hour gear 42a is rotated. The first loaded tooth 62A is formed to be elastically displaceable by being supported by the elastic portion 65.

The elastic portion 65 is provided for each load tooth 62. The elastic portion 65 is a cantilever beam having a load tooth 62 at its tip and formed to be capable of bending. The elastic portion 65 includes a first elastic portion 65A having a first load tooth 62A. The first elastic portion 65A is a portion between a first slit 67 and a second slit 68 formed in the 24-hour gear 42a. The first slit 67 extends radially inward from one tooth groove adjacent to the first load tooth 62A, and then extends toward one side in the circumferential direction. The second slit 68 extends along the first slit 67 from the other tooth groove adjacent to the first load tooth 62A. As a result, the first elastic portion 65A extends with a substantially constant width and is formed to be elastically deformable so as to displace the first load tooth 62A at the tip in the radial direction.

Here, the first standard tooth 61A and the second standard tooth 61B of the multiple standard teeth 61 are defined as follows. The first standard tooth 61A is adjacent to the first load tooth 62A on the downstream side in the forward rotation direction N (predetermined rotation direction) of the 24-hour gear 42a. The second standard tooth 61B is adjacent to the first load tooth 62A on the upstream side in the forward rotation direction N.

The interval between the first load tooth 62A and the first standard tooth 61A is narrower than the interval between the first load tooth 62A and the second standard tooth 61B. The width of the tooth gap between the first load tooth 62A and the first standard tooth 61A is smaller than the tooth thickness of the teeth of the third hour center pinion 34b. The width of the tooth gap between a pair of adjacent teeth 60 is the distance between the pair of teeth 60 on the pitch circle of the 24-hour gear 42a. The tooth thickness of the teeth 60 is the thickness of the teeth 60 on the pitch circle of the 24-hour gear 42a. As a result, when the teeth of the third hour center pinion 34b enter the tooth gap between the first load tooth 62A and the first standard tooth 61A, they come into contact with the first load tooth 62A. The width of the tooth gap between the first load tooth 62A and the second standard tooth 61B is larger than the tooth thickness of the teeth of the third hour center pinion 34b. This allows the teeth of the third hour center pinion 34b to enter the tooth gap between the first load tooth 62A and the second standard tooth 61B without coming into contact with the first load tooth 62A.

The action of the load tooth 62 will now be explained. In the following explanation, unless otherwise specified, it is assumed that the 24-hour gear 42a rotates in the forward direction N. The teeth of the third hour intermediate pinion 34b contact each tooth 60 of the 24-hour gear 42a from the upstream side of the forward direction N.

When the tooth 60 engaging with the third-hour center pinion 34b is replaced by the first standard tooth 61A, the tooth of the third-hour center pinion 34b enters the tooth gap between the first standard tooth 61A and the first load tooth 62A. At this time, the tooth of the third-hour center pinion 34b contacts the first load tooth 62A before and after contact with the first standard tooth 61A, elastically displacing the first load tooth 62A so as to widen the tooth gap between the first standard tooth 61A and the first load tooth 62A. As a result, energy loss occurs in the calendar gear train 41 due to the elastic displacement of the first load tooth 62A. After that, when the tooth 60 engaging with the third-hour center pinion 34b is replaced by the first load tooth 62A, the first load tooth 62A gradually returns to its initial position. Then, when the tooth 60 that engages with the third hour center pinion 34b changes from the first load tooth 62A to the second standard tooth 61B, the tooth of the third hour center pinion 34b completely separates from the first load tooth 62A in the tooth gap between the first load tooth 62A and the second standard tooth 61B, and the first load tooth 62A returns to its initial position.

As described above, when the first load tooth 62A of the 24-hour gear 42a contacts the third hour center pinion 34b, energy loss occurs in the calendar gear train 41. In other words, energy loss occurs in the calendar gear train 41 twice for each rotation of the 24-hour gear 42a. When energy loss occurs in the calendar gear train 41, the load received by the rotor 22 of the first motor 20A fluctuates. This allows the load tooth 62 to vary the load received by the rotor 22. Note that the variation in the load provided by the load tooth 62 only needs to be different from the load when the standard tooth 61 contacts the third hour center pinion 34b. Hereinafter, the load received by the rotor 22 may be referred to as the rotational load.

[Functional configuration of the clock]
6 is a diagram showing an example of the functional configuration of the timepiece according to the first embodiment. The functional configuration of the timepiece 1 will be described with reference to the diagram. The timepiece 1 includes an oscillator circuit 101, a frequency divider circuit 102, a control circuit (controller) 103, a judgment circuit (judgment unit) 104, a voltage detection circuit (voltage detection unit) 105, a motor drive circuit (drive unit) 106, a stepping motor 107, a watch case 2, a movement 4, an hour hand 6, a minute hand 7, a second hand 8, and a date window 5a.
Hereinafter, the oscillator circuit 101, the frequency divider circuit 102, the control circuit 103, the determination circuit 104, the voltage detection circuit 105, and the motor drive circuit 106 will be collectively referred to as a stepping motor control circuit (stepping motor control device) 100. The stepping motor control circuit 100 and the stepping motor 107 will be collectively referred to as a needle drive unit 110.

The oscillator circuit 101 generates a signal having a predetermined frequency and transmits the generated signal to the frequency divider circuit 102. The frequency divider circuit 102 divides the signal received from the oscillator circuit 101 to generate a clock signal that serves as a reference for timekeeping, and transmits the generated clock signal to the control circuit 103. The control circuit 103 transmits control signals to each part of the clock 1 based on the clock signal received from the frequency divider circuit 102, etc., and controls the operation of each part of the clock 1.

The motor drive circuit 106 receives a control signal from the control circuit 103, and drives the stepping motor 107 based on the received control signal. The stepping motor 107 is driven by the motor drive circuit 106 to rotate the hour hand 6, minute hand 7, and second hand 8 via a wheel train.
The voltage detection circuit 105 detects an induced voltage generated in a coil when the stepping motor 107 vibrates. The voltage detection circuit 105 transmits the detected induced voltage to the determination circuit 104.
The determination circuit 104 determines the mechanical load applied to the rotor included in the stepping motor 107 based on the value of the induced voltage detected by the voltage detection circuit 105. For example, the determination circuit 104 determines the mechanical load applied to the rotor based on whether or not the voltage value detected by the voltage detection circuit 105 exceeds a predetermined threshold value.

[Configuration of the needle drive unit]
FIG. 7 is a diagram showing an example of the configuration of the pointer drive unit 110 according to the first embodiment.
The stepping motor 107 includes a stator 201, a rotor 202, a rotor-accommodating through hole 203, inner notches 204, inner notches 205, outer notches 206, outer notches 207, a magnetic core 208, and a coil 209. Hereinafter, the rotor-accommodating through hole 203 will also be referred to as a rotor through hole.

The magnetic core 208 is a member made of a magnetic material and is joined to both ends of the stator 201. The coil 209 is wound around the magnetic core 208, with one end connected to the terminal OUT1 and the other end connected to the terminal OUT2. The coil 209 generates magnetic flux when a driving current i is passed through it. The stator 201 is a member made of a magnetic material. The stator 201 provides the magnetic flux generated by the coil 209 to the rotor 202.

The rotor 202 is formed in a cylindrical shape and is rotatably inserted into the rotor-accommodating through-hole 203 formed in the stator 201. In other words, the stepping motor 107 includes the stator 201 with the rotor-accommodating through-hole 203, the rotor 202 rotatably disposed in the rotor-accommodating through-hole 203, and the coil 209 provided on the stator 201. The rotor 202 is magnetized and has a north pole and a south pole. In the following description, the axis extending from the south pole to the north pole of the rotor 202 is also referred to as the magnetic pole axis A, and the direction extending from the south pole to the north pole of the magnetic pole axis A is also referred to as the positive direction of the magnetic pole axis A (or simply the direction of the magnetic pole axis A).

The rotor 202 rotates in a forward direction to rotate the pointer 155 clockwise via the wheel train, and rotates in a reverse direction to rotate the pointer 155 counterclockwise via the wheel train. That is, the rotor 202 rotates the pointer 155 in a forward direction that rotates the pointer 155 clockwise, and in a reverse direction that is opposite to the forward direction.

The inner notch 204 and the inner notch 205 are notches formed in the wall surface of the rotor-accommodating through hole 203, and determine the stopping position of the rotor 202 relative to the stator 201. That is, for example, when the coil 209 is not excited, the rotor 202 stops at a position where the magnetic pole axis is perpendicular to the line segment connecting the inner notch 204 and the inner notch 205.

The outer notch 206 and the outer notch 207 are notches formed on the inside and outside of the curved stator 201, respectively. A saturable portion 210 is formed between the outer notch 206 and the rotor-accommodating through hole 203, and a saturable portion 211 is formed between the outer notch 207 and the rotor-accommodating through hole 203. The saturable portions 210 and 211 are not magnetically saturated by the magnetic flux of the rotor 202, but are magnetically saturated when the coil 209 is excited, increasing the magnetic resistance.

[Stepping motor drive]
The motor drive circuit 106 generates a drive current i by applying a drive pulse between the terminals (first terminal OUT1 and second terminal OUT2) of the coil 209.
The stepping motor control device 100 rotates the rotor 202 in a fixed direction (for example, the forward direction) by reversing the direction of the drive current i supplied to the coil 209 depending on the direction of the magnetic pole axis A at the stop position of the rotor 202.

As an example, the driving in the forward direction will be described. When the stepping motor control device 100 supplies a driving pulse between the first terminal OUT1 and the second terminal OUT2 of the coil 209, a magnetic flux is generated in the stator 201. As a result, the saturable portion 210 and the saturable portion 211 are saturated and the magnetic resistance increases, and then, due to the interaction between the magnetic pole generated in the stator 201 and the magnetic pole of the rotor 202, the rotor 202 rotates 180 degrees counterclockwise and stops stably. This rotation of about 180 degrees allows the hand 155 of the clock 1 to move one graduation of a specified amount. The movement of the specified amount may be called one step. In order to move the specified amount, a wheel train with an appropriate reduction ratio is appropriately arranged between the rotor 202 and the hand 155. In one example of this embodiment, the movement of one step moves the hand 155 by one second.

When the rotor 202 is in the state shown in FIG. 7, if the stepping motor control device 100 supplies a drive pulse between the first terminal OUT1 and the second terminal OUT2 of the coil 209, a current flows through the coil 209. In this example, when a pulse is applied in which the first terminal OUT1 is at a high potential and the second terminal OUT2 is at a low potential (hereinafter referred to as the positive direction), a current flows in the direction of current i. When a current flows through the coil 209, a magnetic flux is generated in the stator 201. This magnetic flux causes the rotor 202 to rotate approximately 180 degrees counterclockwise and come to a stable stop.

When the rotor 202 is in a state rotated approximately 180 degrees from the state shown in FIG. 7, if the stepping motor control device 100 applies a pulse in which the first terminal OUT1 is at a low potential and the second terminal OUT2 is at a high potential (hereinafter referred to as the negative direction), a magnetic flux is generated in the stator 201 in the opposite direction to when a positive pulse is applied. As a result, the saturable portion 210 and the saturable portion 211 are first saturated, and then, due to the interaction between the magnetic poles generated in the stator 201 and the magnetic poles of the rotor 202, the rotor 202 rotates approximately 180 degrees counterclockwise and stops stably. In this way, by supplying signals of different polarities (alternating signals) to the coil 209, the rotor 202 continuously rotates approximately 180 degrees counterclockwise.

[Oscillation pulse and drive pulse]
Fig. 8 is a diagram showing an example of a swing pulse and a drive pulse in the first embodiment. Fig. 8(A) is a diagram showing a timing chart for explaining the timing at which the swing pulse and the drive pulse are applied, and Fig. 8(B) is a diagram for explaining the angle of the rotor 202. In the explanation of Fig. 8(A), the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, and "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time.
8B, the rotational position of rotor 202 will be described assuming that the position of magnetic pole axis A described in FIG. 7 is 0 degree, and the angle by which magnetic pole axis A rotates counterclockwise is a positive rotation angle. The control from time t11 to time t21 is control for rotating rotor 202 clockwise from 0 degrees to 180 degrees, and the control from time t21 to time t29 is control for rotating rotor 202 clockwise from 180 degrees to 0 degree.

The control circuit 103 rotates the rotor 202 by outputting a drive pulse to the motor drive circuit 106, and oscillates the rotor 202 by outputting an oscillation pulse to the motor drive circuit 106. The oscillation pulse and the drive pulse are each described below.

From time t11 to time t12, the stepping motor control device 100 applies a positive pulse to the second terminal OUT2. As the positive pulse continues to be applied to the second terminal OUT2, the rotor 202 stops at a position rotated -45 degrees. When the stepping motor control device 100 stops applying the pulse at time t12, the rotor 202 is pulled back to the 0 degree position and stops. Here, when the rotor 202 returns from the -45 degree position to the 0 degree position, it rotates counterclockwise at least once to a position of a positive rotation angle and clockwise to a position of a negative rotation angle due to inertia. The rotor 202 repeatedly rotates counterclockwise and clockwise. That is, the rotor 202 vibrates, and as the vibrations attenuate, it stops at the 0 degree position.

The pulse applied from time t11 to time t12 is not intended to rotate the rotor 202 by approximately 180 degrees, but is intended to vibrate the rotor 202 and thereby detect the vibration state of the rotor 202. Hereinafter, the pulse intended to vibrate the rotor 202 will be referred to as a swing pulse, to distinguish it from a normal drive pulse.

The time for which the oscillation pulse is applied only needs to be long enough for the rotor 202 to vibrate, and it is not necessary for the pulse to be applied until the rotor 202 stops at the -45 degree rotation position.

From time t12 to time t15, the stepping motor control device 100 determines the mechanical load that the rotor 202 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 202 receives based on the voltage detected by the voltage detection circuit 105.
Note that the determination circuit 104 may determine the mechanical load applied to the rotor 202 based on the timing at which the voltage detection circuit 105 detects a voltage value exceeding a predetermined voltage value, in addition to or instead of the magnitude of the voltage detected by the voltage detection circuit 105. For example, the determination circuit 104 may determine the mechanical load applied to the rotor 202 based on whether the occurrence timing of the voltage value detected by the voltage detection circuit 105 is within a predetermined period.

From time t15 to time t16, the stepping motor control device 100 applies a positive pulse to the first terminal OUT1. If the positive pulse continues to be applied to the first terminal OUT1, the rotor 202 stops at a position rotated 135 degrees. When the stepping motor control device 100 stops applying the pulse at time t16, the rotor 202 is pulled to a position of 180 degrees and stops. The pulse applied from time t15 to time t16 is a drive pulse because it is a pulse for rotating the rotor 202 approximately 180 degrees. The drive pulse is output by the control circuit 103. That is, the control circuit 103 outputs the drive pulse after a predetermined period has elapsed after outputting the oscillation pulse.

The time for which the drive pulse is applied (the pulse width of the drive pulse) need only be long enough for the rotor 202 to rotate 180 degrees, and the pulse does not need to be applied until the rotor 202 stops at the 135 degree rotation position.
The time for which the drive pulse is applied may be determined according to the mechanical load determined by the determination circuit 104. In this case, the control circuit 103 controls the output time of the drive pulse according to the mechanical load determined by the determination circuit 104.

From time t21 to time t22, the stepping motor control device 100 applies a positive pulse, i.e., an oscillation pulse, to the first terminal OUT1. As the positive pulse continues to be applied to the first terminal OUT1, the rotor 202 stops at a position rotated 135 degrees. When the stepping motor control device 100 stops applying the pulse at time t22, the rotor 202 is pulled back to the 180 degree position and stops. Here, the rotor 202 vibrates when returning from the 135 degree position to the 180 degree position, and stops at the 180 degree position as the vibration dampens.

From time t22 to time t25, the stepping motor control device 100 determines the mechanical load that the rotor 202 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 202 receives based on the voltage detected by the voltage detection circuit 105.

From time t25 to time t26, the stepping motor control device 100 applies a positive pulse, i.e., a drive pulse, to the second terminal OUT2. If the positive pulse continues to be applied to the second terminal OUT2, the rotor 202 stops at a position rotated 315 degrees. When the stepping motor control device 100 stops applying the pulse at time t26, the rotor 202 is pulled to the 0 degree position and stops.

9 is a diagram showing an example of vibration when the loaded teeth and pinion mesh with each other in the first embodiment, and vibration when the standard teeth and pinion mesh with each other. With reference to the drawing, the vibration when the loaded teeth and pinion mesh with each other and the vibration when the standard teeth and pinion mesh with each other will be described.
The upper part of the figure shows an example of a case where the standard teeth and the pinion mesh, and the lower part of the figure shows an example of a case where the load teeth and the pinion mesh. Specifically, an example of a case where the fourth gear 53b having the load teeth 62 meshes with the fourth intermediate pinion 52b will be described. In the description of the figure, the fourth gear 53b may be simply referred to as the gear (or the second gear), and the fourth intermediate pinion 52b may be simply referred to as the pinion (or the first gear). The first gear is a gear that rotates based on the rotation of the rotor 202, and the second gear is a gear having load teeth.
The left side of the figure shows the state of meshing between the gears and the pinions, while the right side of the figure shows the timing of applying the oscillation pulse and the timing of generating the induced voltage.

First, an example of the case where the pinion meshes with the standard teeth 60 in the upper row will be described. As shown in the diagram on the left side of the upper row, when the rotor 202 that drives the pinion vibrates by applying an oscillation pulse, the pinion vibrates due to the vibration of the rotor 202. The range over which the rotor 202 can vibrate varies depending on the amount of backlash between the gear and the pinion. When the standard teeth 60 and the pinion mesh, the backlash is large, so the range over which the rotor 202 can vibrate is also wide.
As shown in the diagram on the upper right side, an oscillation pulse is applied from time t31 to time t32. The rotor 202 vibrates based on the applied oscillation pulse, and an induced voltage is generated from time t33 to time t35. When the standard teeth 60 and the pinion are engaged, the range over which the rotor 202 can vibrate is wide, and the induced voltage generated is also large. In the example shown in the diagram, a voltage v1 is generated at time t34. The determination circuit 104 determines whether the pinion (first gear) is in contact with the loaded tooth of the gear (second gear) as a mechanical load.

Next, an example of the case where the pinion meshes with the lower loaded teeth 62 will be described. As shown in the lower left diagram, when the rotor 202 that drives the pinion vibrates by applying an oscillation pulse, the pinion vibrates due to the vibration of the rotor 202. However, when the loaded teeth 62 and the pinion mesh, the backlash is small, so the range in which the rotor 202 can vibrate is also narrow.
As shown in the diagram on the lower right side, an oscillation pulse is applied from time t41 to time t42. The rotor 202 vibrates based on the applied oscillation pulse, and an induced voltage is generated from time t43 to time t45. However, when the load teeth 62 and the pinion are engaged, the range in which the rotor 202 can vibrate is narrow, so the induced voltage generated is also small. In the example shown in the diagram, a voltage v2 is generated at time t44. Voltage v2 is smaller than voltage v1.

When the pinion meshes between the load teeth 62 and the first standard teeth 61A, the vibration is small, whereas when the pinion meshes between the load teeth 62 and the second standard teeth 61B, the vibration is large. The position of the pointer can be detected by comparing both of these vibrations with the vibration when the pinion meshes with the standard teeth 60.

Figure 10 is a flowchart showing an example of the operation of the stepping motor control device 100 in the first embodiment. A series of operations of the stepping motor control device 100 will be described with reference to the figure.

(Step S110) The control circuit 103 outputs a swing pulse to the motor drive circuit 106. The motor drive circuit 106 drives the stepping motor 107 based on the acquired swing pulse.

(Step S120) The voltage detection circuit 105 detects the induced voltage caused by the vibration of the rotor 202. The determination circuit 104 determines the mechanical load of the rotor 202 based on the value of the detected induced voltage or the timing at which the induced voltage is detected.

(Step S130) If a predetermined time has elapsed since the oscillation pulse was output (Step S130; YES), the control circuit 103 advances the process to Step S140. If a predetermined time has not elapsed since the oscillation pulse was output (Step S130; NO), the voltage detection circuit 105 repeats Step S120.

(Step S140) The control circuit 103 outputs a drive pulse to the motor drive circuit 106. The magnitude (voltage and time) of the drive pulse may be a predetermined value, or may be a value based on the mechanical load of the rotor 202 determined in step S120.

[Second embodiment]
11 is a plan view of the front side of the movement in the second embodiment. The second embodiment will be described with reference to this figure. A timepiece 1-2 according to the second embodiment differs from the first embodiment in that it has a second motor 20B-2 instead of the second motor 20B in the first embodiment. The second motor 20B is a one-coil motor, whereas the second motor 20B-2 is a two-coil motor. In other words, the second embodiment is an example of a timepiece 1-2 that has a two-coil motor. Configurations similar to those in the first embodiment may be denoted by the same reference numerals as in the first embodiment, and description thereof may be omitted.

FIG. 12 is a diagram showing an example of the configuration of a pointer drive unit 110A in the second embodiment.
The stepping motor 107A is an example of the second motor 20B-2. That is, the stepping motor 107A is a two-coil motor. The stepping motor 107A includes a stator 120 having a rotor housing hole 125, and a rotor 130 having magnetic polarity by being magnetized into two poles in the radial direction and rotatably disposed in the rotor housing hole 125. The stepping motor 107A operates in unit steps to rotate the pointer.

The stator 120 includes a stator body 121, a first magnetic core (first end) 140A magnetically joined to the stator body 121, a second magnetic core (second end) 140B, a first coil 150A wound around the first magnetic core 140A, and a second coil 150B wound around the second magnetic core 140B.

The stator body 121 is formed of a plate material using a high magnetic permeability material such as permalloy. The stator body 121 has a T-shaped first yoke 122 and a pair of second yokes 123 and 124, and is formed in an H-shape in a plan view. That is, the T-shaped first yoke 122 has a straight portion 122a extending in a predetermined first direction, and a pair of protruding portions 122b and 122c protruding from one end of the straight portion 122a to both sides in a second direction perpendicular to the first direction. The second yoke 123 is provided so as to protrude from the other end of the straight portion 122a to the same side as the protruding portion 122b, and the second yoke 124 is provided so as to protrude from the other end of the straight portion 122a to the same side as the protruding portion 122c. With this configuration of the first yoke 122, the second yoke 123, and the second yoke 124, the stator body 121 is formed in an H-shape in plan view. The first yoke 122, the second yoke 123, and the second yoke 124 are integrally formed.

At the intersection of the first yoke 122, the second yoke 123, and the second yoke 124 of the stator body 121, the rotor accommodation hole 125 in the shape of a circular hole as described above is formed. A pair of notches 125a are formed on the inner circumferential surface of the rotor accommodation hole 125 so as to face each other in the second direction. The notches 125a are cut in an arc shape. These notches 125a are configured as positioning parts for determining the stop position of the rotor 130. When the magnetic pole axis of the rotor 130 is at a position perpendicular to the line segment connecting the pair of notches 125a, that is, when the magnetic pole axis is at a position along the first direction, the potential energy of the rotor 130 becomes the lowest and the rotor 130 stops stably. Hereinafter, the stop position of the rotor 130 when the magnetic pole axis of the rotor 130 is along the first direction and the N pole of the rotor 130 faces the first yoke 122 side (the position shown in FIG. 12) is referred to as the first stop position. In addition, the stop position of the rotor 130 when the magnetic pole axis of the rotor 130 is aligned along the first direction and the south pole of the rotor 130 faces the first yoke 122 side is called the second stop position.

In addition, around the rotor accommodating hole 125 in the stator body 121, three notches 126 are formed, cut from the outer periphery of the stator body 121 in a plan view toward the rotor accommodating hole 125. Each notch 126 is formed at a corner where the first yoke 122 and the second yoke 123 are connected, at a corner where the first yoke 122 and the second yoke 124 are connected, and at a portion where the second yoke 123 and the second yoke 124 are connected. Each notch 126 is cut in an arc shape.

The periphery of the rotor accommodating hole 125 in the stator body 121 is locally narrowed by each notch 126 (hereinafter, the locally narrowed portion may be referred to as the narrow portion). The narrow portion is more susceptible to magnetic saturation than other portions of the stator body 121, and the stator body 121 is magnetically divided into three around the rotor accommodating hole 125 due to the magnetic saturation of the narrow portion. The stator body 121 has a first magnetic pole portion 120A arranged at a position corresponding to the second yoke 123 around the rotor 130, a second magnetic pole portion 120B arranged at a position corresponding to the second yoke 124 around the rotor 130, and a third magnetic pole portion 120C arranged at a position corresponding to the straight portion 122a of the first yoke 122 around the rotor 130.

Here, each portion of the rotor 130 is divided into the portions indicated by reference numerals 130A to 130D by the magnetic pole axis A and a straight line B that intersects at right angles. Of the first magnetic pole portion 120A, the portion that runs along the rotor accommodating hole 125 from the notch 126 formed in the portion where the second yoke 123 and the second yoke 124 are connected to the notch 125a formed in the second yoke 123 is disposed opposite the portion indicated by reference numeral 130A of the rotor 130 located at the first stop position (the portion indicated by reference numeral 130C of the rotor 130 located at the second stop position). The portion of the second magnetic pole portion 120B that runs along the rotor accommodating hole 125 from the notch 126 formed at the connection between the second yoke 123 and the second yoke 124 to the notch 125a formed in the second yoke 124 is positioned opposite the portion indicated by the reference symbol 130B of the rotor 130 positioned in the first stop position (the portion indicated by the reference symbol 130D of the rotor 130 positioned in the second stop position).
The third magnetic pole portion 120C is disposed to face the N pole of the rotor 130 located at the first stop position (the S pole of the rotor 130 located at the second stop position).

Each of the first magnetic core 140A and the second magnetic core 140B is formed of a high magnetic permeability material such as permalloy. The first magnetic core 140A is magnetically connected to the tip of the protruding portion 122c and the tip of the second yoke 124. The second magnetic core 140B is magnetically connected to the tip of the protruding portion 122b and the tip of the second yoke 123. Both ends of each of the first magnetic core 140A and the second magnetic core 140B are connected to the stator body 121, for example, by screws.

The first coil 150A is wound around the first magnetic core 140A and is magnetically coupled to the second magnetic pole portion 120B and the third magnetic pole portion 120C. The first coil 150A has a first terminal 150Aa and a second terminal 150Ab. The first coil 150A is wound so that when a current flows from the first terminal 150Aa to the second terminal 150Ab, a magnetic field is generated within the first coil 150A that is directed from the protruding portion 122c side to the second yoke 124 side.

The second coil 150B is wound around the second magnetic core 140B and is magnetically coupled to the first magnetic pole portion 120A and the third magnetic pole portion 120C. The second coil 150B has a first terminal 150Ba and a second terminal 150Bb. The second coil 150B is wound so that when a current flows from the first terminal 150Ba to the second terminal 150Bb, a magnetic field is generated within the second coil 150B that flows from the second yoke 123 side to the protruding portion 122b side.

The wire diameter of the conductor of the first coil 150A is the same as that of the conductor of the second coil 150B. The number of windings of the first coil 150A is the same as that of the second coil 150B. The terminals of the first coil 150A and the second coil 150B are connected to the stepping motor control device 100. In the following description, the potential of the first terminal 150Aa of the first coil 150A is out1, the potential of the second terminal 150Ab of the first coil 150A is out2, the potential of the first terminal 150Ba of the second coil 150B is out3, and the potential of the second terminal 150Bb of the second coil 150B is out4.

When magnetic flux is generated from the first coil 150A or the second coil 150B in the stator 120 configured in this manner, the magnetic flux flows along the first magnetic core 140A and the second magnetic core 140B and the stator body 121. Then, the polarity of the first magnetic pole portion 120A, the second magnetic pole portion 120B, and the third magnetic pole portion 120C described above is switched depending on the state of current flow through the first coil 150A or the second coil 150B.

That is, the stepping motor 107A includes a rotor 130, a stator 120, a first coil 150A, and a second coil 150B. The stator 120 provides a magnetic flux that generates a rotational force to the rotor 130. The rotor 130 is magnetized with at least two poles, an N pole and an S pole, and rotates the pointer. The first coil 150A supplies magnetic flux to the first magnetic core 140A at both ends of the stator 120. The second coil 150B supplies magnetic flux to the second magnetic core 140B at both ends of the stator 120.
The drive pulse output by the control circuit 103 excites the first coil 150A and the second coil 150B, thereby driving the rotor 130 by a reference rotation angle according to the number of poles.

The reference rotation angle according to the number of poles may be the angle of one rotation of the rotor 130 divided by the number of poles to which the rotor is magnetized. For example, if the rotor 130 is exemplified as having two poles, the reference rotation angle according to the number of poles is the angle of one rotation divided by two (180°). If the rotor 130 is exemplified as having four poles, the reference rotation angle according to the number of poles is the angle of one rotation divided by four (90°).

13 is a diagram showing an example of a swing pulse and a drive pulse in the second embodiment. In the explanation of the figure, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.
12 is defined as 0 degrees, the rotational position of the rotor 202 will be described. The control from time t51 to time t61 is control for rotating the rotor 202 counterclockwise from 0 degrees to 180 degrees, and the control from time t61 to time t69 is control for rotating the rotor 202 counterclockwise from 180 degrees to 0 degrees.

From time t51 to time t52, the stepping motor control device 100 applies a positive pulse to the fourth terminal OUT4. As the positive pulse continues to be applied to the fourth terminal OUT4, the rotor 130 stops at a position rotated 45 degrees. When the stepping motor control device 100 stops applying the pulse at time t52, the rotor 130 is pulled back to the 0 degree position and stops. Here, when the rotor 130 returns from the 45 degree position to the 0 degree position, it rotates counterclockwise at least once due to inertia to a position of negative rotation angle and then clockwise to a position of positive rotation angle, repeating this process. In other words, the rotor 130 vibrates, and as the vibrations attenuate, it stops at the 0 degree position.

From time t52 to time t55, the stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105.

From time t55 to time t57, the stepping motor control device 100 applies a drive pulse. The positive pulse applied to the fourth terminal OUT4 from time t55 to time t56 is referred to as the first drive pulse. The positive pulse applied to the second terminal OUT2 from time t56 to time t57 is referred to as the second drive pulse. When the positive pulse continues to be applied to the second terminal OUT2, the rotor 130 stops at a position rotated 135 degrees. When the stepping motor control device 100 stops applying the pulse at time t57, the rotor 130 is pulled to the 180 degree position and stops.

From time t61 to time t62, the stepping motor control device 100 applies a positive pulse, i.e., an oscillation pulse, to the third terminal OUT3. As the positive pulse continues to be applied to the third terminal OUT3, the rotor 130 stops at a position rotated 225 degrees. When the stepping motor control device 100 stops applying the pulse at time t62, the rotor 130 is pulled back to the 180 degree position and stops. Here, the rotor 130 vibrates when returning from the 225 degree position to the 180 degree position, and stops at the 180 degree position as the vibration dampens.

From time t62 to time t65, the stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105.

From time t65 to time t67, the stepping motor control device 100 applies a drive pulse. Specifically, from time t65 to time t66, the stepping motor control device 100 applies a positive pulse to the third terminal OUT3 as the first drive pulse, and from time t66 to time t67, it applies a positive pulse to the first terminal OUT1 as the second drive pulse. When the positive pulse continues to be applied to the first terminal OUT1, the rotor 130 stops at a position rotated 315 degrees. When the stepping motor control device 100 stops applying the pulse at time t66, the rotor 130 is pulled to the 0 degree position and stops.

Fig. 14 is a diagram showing a modified example of the oscillation pulse and the drive pulse in the second embodiment. The modified example shown in the figure is different from the example described in Fig. 13 in that it includes an oscillation pulse (first oscillation pulse) for rotating a predetermined angle in the forward direction from the rest position, and an oscillation pulse (second oscillation pulse) for rotating a predetermined angle in the reverse direction from the rest position. In the explanation of the figure, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.
12 is defined as 0 degrees, the rotational position of the rotor 202 will be described. The control from time t51 to time t61 is control for rotating the rotor 202 counterclockwise from 0 degrees to 180 degrees, and the control from time t61 to time t69 is control for rotating the rotor 202 counterclockwise from 180 degrees to 0 degrees.

From time t71 to time t74, the stepping motor control device 100 applies a swing pulse. Specifically, from time t71 to time t72, the stepping motor control device 100 applies a positive pulse (first swing pulse) to the fourth terminal OUT4. When the positive pulse is applied to the fourth terminal OUT4, the rotor 130 starts to rotate toward the 45 degree position. When the stepping motor control device 100 stops applying the pulse at time t72, the rotor 130 starts to rotate toward the 0 degree position. Next, the stepping motor control device 100 applies a positive pulse (second swing pulse) to the first terminal OUT1. When the positive pulse is applied to the first terminal OUT1, the rotor 130 starts to rotate toward the 315 degree position. Here, the rotor 130 is pulled to the 45 degree position once, and then pulled to the 315 degree position, so that it vibrates greatly due to inertia. The rotor 130 stops at the 0 degree position as the vibration dampens.

From time t74 to time t75, the stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105.

The control from time t75 to time t81 is similar to the control from time t55 to time t61 described in FIG. 13, so a description thereof will be omitted.

From time t81 to time t84, the stepping motor control device 100 applies a swing pulse. Specifically, from time t81 to time t82, the stepping motor control device 100 applies a positive pulse (first swing pulse) to the third terminal OUT3. When the positive pulse is applied to the third terminal OUT3, the rotor 130 starts to rotate toward the 225 degree position. When the stepping motor control device 100 stops applying the pulse at time t82, the rotor 130 starts to rotate toward the 180 degree position. Next, the stepping motor control device 100 applies a positive pulse (second swing pulse) to the second terminal OUT2. When the positive pulse is applied to the second terminal OUT2, the rotor 130 starts to rotate toward the 135 degree position. Here, the rotor 130 is pulled to the 225 degree position once, and then pulled to the 135 degree position, so that it vibrates greatly due to inertia. The rotor 130 stops at the 180 degree position as the vibrations dampen.

From time t84 to time t85, the stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the oscillation pulse. Specifically, the determination circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105.

The control from time t85 to time t89 is similar to the control from time t65 to time t69 described in FIG. 13, so a description thereof will be omitted.

In the example shown in the modified example described above, the control circuit 103 outputs both a first oscillation pulse that oscillates the rotor 130 by outputting a pulse of energy that rotates the rotor 130 in the forward direction, and a second oscillation pulse that oscillates the rotor 130 by outputting a pulse of energy that rotates the rotor 130 in the opposite direction to the forward direction after outputting the first oscillation pulse, thereby making it possible to greatly vibrate the rotor 130. The control circuit 103 may output only the first oscillation pulse as an oscillation pulse as in an example of the second embodiment, or may output both the first oscillation pulse and the second oscillation pulse as an oscillation pulse as in the modified example of the second embodiment.

When both the first and second oscillation pulses are output, the rotor 130 can be vibrated greatly, but the time required for detection may become longer. Therefore, when the oscillation pulse is output according to a predetermined cycle in which the drive pulse is output, it may be configured to output only the first oscillation pulse. Also, when the oscillation pulse is output at a predetermined timing that does not correspond to the predetermined cycle in which the drive pulse is output, it may be configured to output both the first and second oscillation pulses.

The control unit 103 may be configured to have a rocking pulse output mode in which a rocking pulse is output, and a rocking pulse non-output mode in which a rocking pulse is not output.

[Summary of Effects of the Embodiments]
According to the above-described embodiment, the stepping motor control device 100 includes a control circuit 103 that outputs a drive pulse and a swing pulse, a voltage detection circuit 105 that detects the vibration of the rotor, and a determination circuit 104 that determines the mechanical load on the rotor based on the detected voltage, thereby detecting the vibration of the rotor when the swing pulse is output. Therefore, according to this embodiment, even if the vibration of the rotor is small due to the motor, the rotor can be vibrated and an induced voltage is generated, so that the rotation state of the rotor can be detected and the mechanical load on the rotor can be determined.

Conventionally, when the motor is a two-coil motor, the induced voltage is distributed to the two coils, and the effect of the electromagnetic brake by the coils is strengthened, so that the vibration of the rotor during normal operation is small. However, according to this embodiment, since an oscillation pulse is applied to vibrate the rotor, it is possible to reliably detect the rotation state of the rotor and to determine the mechanical load of the rotor.
In addition, depending on the motor, the inertia of the rotor may be small, or the magnetic holding force of the stator may be small. In such cases, the vibration of the rotor during normal driving is small, making it difficult to detect the rotation state of the rotor. However, according to this embodiment, since a vibration pulse is applied to vibrate the rotor, it is possible to reliably detect the rotation state of the rotor and determine the mechanical load of the rotor.

The mechanical load determined by the stepping motor control device 100 is not limited to the example of a gear having load teeth, but broadly includes loads that occur when rotating a date wheel.

According to the embodiment described above, the control circuit 103 outputs a drive pulse after a predetermined period of time has elapsed after outputting a swing pulse. Therefore, the control circuit 103 outputs a drive pulse after the vibration of the rotor caused by the swing pulse has sufficiently attenuated, so that it is possible to prevent loss of synchronization caused by the vibration caused by the swing pulse.
The predetermined period from the output of the oscillation pulse to the output of the drive pulse is a period of time sufficient for the vibration of the rotor caused by the oscillation pulse to attenuate, and may be determined based on the inertia of the rotor.

According to the embodiment described above, the stepping motor control device 100 detects the state in which the pinion and the load teeth are engaged as a mechanical load. Therefore, according to this embodiment, the reference pointer position can be identified.

According to the embodiment described above, the control circuit 103 controls the output time of the drive pulse in response to the mechanical load determined by the determination circuit 104. Therefore, when the mechanical load increases, the time for which the drive pulse is applied is lengthened (i.e., a large amount of energy is applied), thereby preventing the stepping motor from losing synchronization.
For example, when driving a calendar, the load is large, so it is preferable to rotate the rotor with more energy than usual. According to this embodiment, even in such a case, the energy to be applied can be varied according to the load.

According to the above-described embodiment, the stepping motor control device 100 includes a first oscillation pulse and a second oscillation pulse. Here, when driving the stepping motor, depending on the driving speed and the size of the connected load, there are cases where it is preferable to provide only the first oscillation pulse, and cases where it is preferable to provide both the first oscillation pulse and the second oscillation pulse. According to this embodiment, it is possible to provide a suitable oscillation pulse depending on the driving speed of the stepping motor and the size of the connected load.

According to the above-described embodiment, the stepping motor control device 100 can prevent erroneous detection of mechanical load by applying the first and second oscillation pulses in the case of normal hand movement. Furthermore, when driving the hands at high speed, the stepping motor control device 100 can shorten the detection time and drive the hands at high speed by applying only the first oscillation pulse.

According to the above-described embodiment, the determination circuit 104 determines the mechanical load based on whether the voltage value detected by the voltage detection circuit 105 exceeds a threshold value. Therefore, according to this embodiment, the mechanical load of the rotor can be easily detected.

According to the embodiment described above, the judgment circuit 104 judges whether or not an induced voltage is occurring at the timing when an induced voltage is expected to occur due to the vibration of the rotor after the oscillation pulse is given. Therefore, according to this embodiment, it is possible to prevent erroneous detection that occurs when the load temporarily increases due to an external load.

According to the above-described embodiment, the stepping motor control device 100 has a mode in which a rocking pulse is output and a mode in which a rocking pulse is not output. Therefore, according to this embodiment, when a rocking pulse is not required, the rocking pulse is not output, thereby reducing power consumption.

[Third embodiment]
Next, a third embodiment will be described with reference to Fig. 15 to Fig. 18. In the above-mentioned embodiment, an example of a case where the energy of the drive pulse is changed by the stepping motor control device 100 has been described. Specifically, an example of a case where the control circuit 103 controls the output time of the drive pulse in accordance with the mechanical load determined by the determination circuit 104, thereby controlling the energy of the drive pulse has been described. In the third embodiment, a specific example of a case where the energy for driving the stepping motor 107 is controlled by various methods will be described.

In the example described with reference to Figures 15 to 18, an example will be described in which the stepping motor is a two-coil motor. However, the third embodiment is not limited to the two-coil motor example. Even if the watch 1 has a one-coil motor instead of a two-coil motor, the same processing as described below can be applied.

Figure 15 is a diagram showing an example of controlling the energy for driving a stepping motor by controlling the output time of a drive pulse in the third embodiment. With reference to the figure, an example of controlling the energy for driving a stepping motor by controlling the output time of a drive pulse will be described. Figure 15 (A) shows an example of a case where induced voltage detection was possible, and Figure 15 (B) shows an example of a case where induced voltage detection was not possible.

In the explanation of FIG. 15, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.

First, an example of a case where an induced voltage can be detected will be described with reference to FIG.
At time t111, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated in "Out4". The judgment circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105. Specifically, the judgment circuit 104 determines that the induced voltage has been normally detected because the induced voltage is equal to or greater than a predetermined threshold value TH.

Next, an example of a case where an induced voltage cannot be detected will be described with reference to FIG.
At time t121, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 judges the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated at "Out4". The judgment circuit 104 judges that the induced voltage is not detected normally because it is equal to or less than a predetermined threshold value TH. In this case, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the output time of the drive pulse. Specifically, the control circuit 103 controls the energy for driving the stepping motor 107 to be larger by lengthening the output time of the drive pulse applied to "Out1" at time 125 and the output time of the drive pulse applied to "Out3" at time 127.

Figure 16 is a diagram showing an example of controlling the energy for driving a stepping motor by controlling the excitation method of the stepping motor in the third embodiment. With reference to the figure, an example of controlling the energy for driving a stepping motor by controlling the excitation method of the stepping motor will be described. Figure 16 (A) shows an example of a case where induced voltage detection was possible, and Figure 16 (B) shows an example of a case where induced voltage detection was not possible.

In the explanation of FIG. 16, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.

Next, an example of a case where an induced voltage can be detected will be described with reference to FIG.
At time t211, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated in "Out4". The judgment circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105. Specifically, the judgment circuit 104 determines that the induced voltage has been normally detected because the induced voltage is equal to or greater than a predetermined threshold value TH.
In the example shown in FIG. 16A, the control circuit 103 controls the stepping motor 107 by one-phase excitation.

Next, an example of a case where an induced voltage cannot be detected will be described with reference to FIG.
At time t221, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated at "Out4". The determination circuit 104 determines that the induced voltage is not normally detected because the induced voltage is equal to or less than a predetermined threshold value TH. In this case, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the excitation method of the stepping motor 107. Specifically, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the excitation method of the stepping motor 107 from one-phase excitation to two-phase excitation. More specifically, the control circuit 103 applies “Out1” and “Out3” at time 225, and applies “Out3” only at time 227, thereby performing two-phase excitation drive and controlling so that the energy used to drive the stepping motor 107 is increased.

Fig. 17 is a diagram showing an example of a case where the energy for driving a stepping motor is controlled by controlling the duty ratio of a drive pulse in the third embodiment. With reference to the figure, an example of a case where the energy for driving a stepping motor is controlled by controlling the duty ratio of a drive pulse will be described. Fig. 17(A) shows an example of a case where induced voltage detection is possible, and Fig. 17(B) shows an example of a case where induced voltage detection is not possible.
In the example shown in the figure, the control circuit 103 controls the stepping motor 107 by applying a PWM signal as a drive pulse.

In the explanation of FIG. 17, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.

Next, an example of a case where an induced voltage can be detected will be described with reference to FIG.
At time t311, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated in "Out4". The judgment circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105. Specifically, the judgment circuit 104 determines that the induced voltage has been normally detected because the induced voltage is equal to or greater than a predetermined threshold value TH.
In the example shown in FIG. 17A, the control circuit 103 controls the stepping motor 107 by applying a PWM signal as a drive pulse at times 315 and 317 .

Next, an example of a case where an induced voltage cannot be detected will be described with reference to FIG.
At time t321, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 judges the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated at "Out4". The judgment circuit 104 judges that the induced voltage is not detected normally because it is equal to or less than a predetermined threshold value TH. In this case, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the duty ratio of the drive pulse. Specifically, the control circuit 103 controls the energy for driving the stepping motor 107 to be larger by making the duty ratio of the drive pulse applied at time 325 and time 327 larger than the duty ratio of the drive pulse applied at time 315 and time 317.

Fig. 18 is a diagram showing an example of a case where the energy for driving a stepping motor is controlled by controlling the voltage of a drive pulse in the third embodiment. With reference to the figure, an example of a case where the energy for driving a stepping motor is controlled by controlling the duty ratio of the drive pulse will be described. Fig. 18(A) shows an example of a case where induced voltage detection is possible, and Fig. 18(B) shows an example of a case where induced voltage detection is not possible.
In this embodiment, the motor drive circuit 106 includes a voltage converter such as a DC/DC converter or an LDO (Low Dropout), not shown, and is configured to be able to select the voltage to be applied to the stepping motor 107 .

In the explanation of FIG. 18, the horizontal axis indicates time, "Out1" indicates the magnitude of the voltage applied to the first terminal OUT1 at each time, "Out2" indicates the magnitude of the voltage applied to the second terminal OUT2 at each time, "Out3" indicates the magnitude of the voltage applied to the third terminal OUT3 at each time, and "Out4" indicates the magnitude of the voltage applied to the fourth terminal OUT4 at each time.

Next, an example of a case where an induced voltage can be detected will be described with reference to FIG.
At time t411, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated in "Out4". The judgment circuit 104 determines the mechanical load that the rotor 130 receives based on the voltage detected by the voltage detection circuit 105. Specifically, the judgment circuit 104 determines that the induced voltage has been normally detected because the induced voltage is equal to or greater than a predetermined threshold value TH.
In the example shown in FIG. 17A, the control circuit 103 controls the stepping motor 107 by applying a voltage V1 as a drive pulse at times 415 and 417.

Next, an example of a case where an induced voltage cannot be detected will be described with reference to FIG.
At time t421, the stepping motor control device 100 applies a swing pulse to the stepping motor 107 by controlling "Out4". The stepping motor control device 100 determines the mechanical load that the rotor 130 receives due to the application of the swing pulse. The voltage detection circuit 105 detects the induced voltage generated at "Out4". The determination circuit 104 determines that the induced voltage is equal to or lower than a predetermined threshold value TH and therefore the induced voltage has not been detected normally. In this case, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the voltage of the drive pulse. Specifically, the control circuit 103 controls the energy for driving the stepping motor 107 to be large by setting the voltage of the drive pulse applied at time 415 and time 417 to voltage V2, which is higher than voltage V1.
For example, voltage V1 may be a voltage generated by a voltage converter, and voltage V2 may be a battery power supply voltage.

[Summary of Effects of Third Embodiment]
According to the embodiment described above, the stepping motor control device 100 includes the control circuit 103, and thereby controls the energy for driving the stepping motor 107 in accordance with the mechanical load determined by the determination circuit 104. Therefore, according to this embodiment, when the mechanical load increases, the energy for driving the stepping motor 107 is increased, thereby making it possible to prevent the stepping motor from losing synchronization.

In addition, according to the above-described embodiment, when the determination circuit 104 determines that the induced voltage could not be detected normally, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the output time of the drive pulse. Since the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the output time of the drive pulse, it is possible to easily control the energy for driving the stepping motor 107 without using new hardware for varying the energy.

Furthermore, according to the above-described embodiment, when the determination circuit 104 determines that the induced voltage could not be detected normally, the control circuit 103 controls the excitation method of the stepping motor 107, thereby controlling the energy that drives the stepping motor 107. Since the control circuit 103 controls the energy that drives the stepping motor 107 by controlling the excitation method of the stepping motor 107, it is possible to easily control the energy that drives the stepping motor 107 without using new hardware for varying the energy. Furthermore, the control circuit 103 can reliably control the energy that drives the stepping motor 107.

In addition, according to the above-described embodiment, when the determination circuit 104 determines that the induced voltage could not be detected normally, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the duty ratio of the drive pulse. Since the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the duty ratio of the drive pulse, it is possible to control the energy for driving the stepping motor 107 even when the drive pulse is PWM driven.

In addition, according to the above-described embodiment, when the determination circuit 104 determines that the induced voltage could not be detected normally, the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the voltage of the drive pulse. Since the control circuit 103 controls the energy for driving the stepping motor 107 by controlling the voltage of the drive pulse, it is possible to control the energy for driving the stepping motor 107 even when there is a time constraint on the time during which the drive pulse can be applied.

In this embodiment, the above-mentioned methods can be combined. For example, both the application time and voltage of the drive pulse may be controlled to be changed simultaneously, or both the duty ratio and voltage of the PWM may be controlled to be changed simultaneously. Furthermore, when changing to two-phase excitation, at least one of the application time and voltage of the drive pulse may be controlled to be changed simultaneously.
By combining these, the energy for driving the stepping motor 107 can be controlled with higher resolution.

[Fourth embodiment]
Next, a fourth embodiment will be described with reference to Fig. 19. In the above-mentioned embodiment, a modified example of the oscillation pulse has been described with reference to Fig. 14. The fourth embodiment will supplement the modified example of the oscillation pulse described with reference to Fig. 14.

Fig. 19 is a diagram showing an example of a rocking pulse and a driving pulse in the fourth embodiment. The example described with reference to this figure differs from the example described with reference to Fig. 14 in that the rotation direction of the rocking pulse is not limited.
14, the rotor 130 is rotated in the forward direction by the first oscillation pulse, and then rotated in the reverse direction by the second oscillation pulse. However, in this embodiment, the rotor 130 may be rotated in the reverse direction by the first oscillation pulse, and then rotated in the reverse direction by the second oscillation pulse.

In this embodiment, the oscillation pulse is either the first oscillation pulse or the second oscillation pulse, which is the same as the example described with reference to FIG. 14. However, in this embodiment, the rotation direction of the first oscillation pulse or the second oscillation pulse is not limited, which is different from the example described with reference to FIG. 14. That is, the first oscillation pulse has energy that rotates the rotor 130 in the first rotation direction, and causes the rotor 130 to oscillate. The second oscillation pulse is an oscillation pulse that is applied after the first oscillation pulse is output, has energy that rotates the rotor 130 in the second rotation direction, and causes the rotor 130 to oscillate.

Specifically, the first rotation direction may be a forward direction, and the second rotation direction may be a reverse direction opposite to the first rotation direction. Also, the first rotation direction may be a reverse direction, and the second rotation direction may be a forward direction opposite to the first rotation direction.

[Summary of the effects of the fourth embodiment]

According to the embodiment described above, the control circuit 103 applies a first oscillation pulse and a second oscillation pulse as drive pulses, and the rotation direction of the first oscillation pulse and the second oscillation pulse is arbitrary. Therefore, according to this embodiment, the rotor of the stepping motor 107 can be suitably oscillated.

[Fifth embodiment]
Next, the fifth embodiment will be described. First, the problem to be solved by the fifth embodiment will be described. The oscillation pulse described in the above embodiment is required to provide energy suitable for preventing the rotor from vibrating significantly when meshing with the load teeth and for the rotor to oscillate when meshing with the normal teeth.
For example, if the energy of the oscillation pulse is too large, even a loaded tooth will oscillate, and if the energy of the oscillation pulse is too small, even a normal tooth may not oscillate. In other words, it is desirable to suitably adjust the energy of the oscillation pulse according to the load of the gear. In this embodiment, the object is to suitably adjust the energy of the oscillation pulse.

Figure 20 is a diagram showing whether or not an induced voltage is detected when the voltage of the drive pulse and the oscillation pulse are changed in the fifth embodiment. On the left side of the figure, an example of a case where the spring force of the load tooth is strong is shown as "high load". On the left side of the figure, an example of a case where the spring force of the load tooth is weak is shown as "low load". For each of the cases of "high load" and "low load", an example of a case where the applied voltage of the oscillation pulse is "3.0 [V]" and "1.8 [V]" are shown. 3.0 [V] is assumed to be the power supply voltage, and 1.8 [V] is assumed to be a voltage generated from the power supply voltage by a DC/DC converter, LDO, etc.

The vertical axis in the figure indicates the magnitude of the energy of the oscillation pulse, with the energy decreasing toward the top and increasing toward the bottom. In the example shown in the figure, the energy is varied by changing the time for which the oscillation pulse is applied. Note that the energy differs between an example where the oscillation pulse is set to "3.0 [V]" and an example where the oscillation pulse is set to "1.8 [V]".
In the figure, the horizontal axis indicates steps, with one cell representing one step. In the figure, 11 steps are shown, centered on the load tooth, out of the 360 steps in one rotation of the gear.
Shaded cells in the figure indicate that a tooth has been detected as a loaded tooth. Non-shaded cells in the figure indicate that a tooth has been detected as a normal tooth. The boundaries between the shaded cells and the non-shaded cells indicate the minimum and maximum energy amounts of the oscillation pulse. In other words, by applying an energy amount between the minimum and maximum energy amounts as an oscillation pulse, normal teeth and loaded teeth can be suitably detected.

As an example of the "high load" case, when the oscillation pulse is driven at 3.0 [V], the difference between the minimum and maximum energy amounts (i.e., the difference in the pulse application time) is 0.27 [ms]. When the oscillation pulse is driven at 1.8 [V], the difference between the minimum and maximum energy amounts is 0.78 [ms].
As an example of the "low load" case, when the oscillation pulse is driven at 3.0 [V], the difference between the minimum and maximum energy amounts is 0.18 [ms]. When the oscillation pulse is driven at 1.8 [V], the difference between the minimum and maximum energy amounts is 0.56 [ms].

In both the "high load" and "low load" cases, the difference between the minimum and maximum energy amounts is greater when the oscillation pulse is driven at 1.8 V. In other words, by setting the oscillation pulse to a voltage lower than the drive pulse, the energy of the oscillation pulse can be controlled with high resolution.

In this embodiment, in order to control the energy of the oscillation pulse with high resolution, the oscillation pulse has a voltage smaller than that of the drive pulse. Specifically, when the drive pulse is output from the control circuit 103, the motor drive circuit 106 drives the stepping motor 107 with a first voltage (e.g., 3.0 [V]), and when the oscillation pulse is output from the control circuit 103, the motor drive circuit 106 drives the stepping motor 107 with a second voltage (e.g., 1.8 [V]) lower than the first voltage.
The first voltage may be, for example, the power supply voltage of a battery that drives the timepiece 1, and the second voltage may be, for example, a voltage obtained by lowering the power supply voltage of the battery using a DC/DC converter, LDO, or the like.

[Summary of Effects of Fifth Embodiment]
According to this embodiment, the oscillation pulse has a voltage smaller than that of the drive pulse, so that the oscillation pulse energy can be controlled with high resolution. Therefore, the oscillation pulse energy can be suitably controlled. Therefore, according to this embodiment, the normal teeth and the loaded teeth can be accurately detected.

Sixth Embodiment
Next, a sixth embodiment will be described. First, a problem to be solved by the stepping motor control device 100 according to the sixth embodiment will be described.
The load on the multiple wheel trains of the timepiece 1 may become large after years of use. Even if the time period of use is short, the overall load may become large depending on the usage conditions and magnetic field environment. In this embodiment, when the load on the wheel trains of the timepiece 1 becomes large, the energy for driving the stepping motor 107 is controlled to be increased, thereby preventing problems such as loss of synchronism.

21 is a diagram for explaining the drive pulse rank control in the sixth embodiment. A series of operations of the stepping motor control device 100 according to the sixth embodiment will be described with reference to the drawing.
In this embodiment, the gear is assumed to rotate once in 360 steps. The process in this embodiment is started when the power is turned on, and the control is repeated thereafter.

(Step S211) The stepping motor control device 100 sets the drive rank dr to 0 and the stable number NS to 0 as initial conditions. The drive rank dr indicates the rank of the energy that drives the stepping motor 107. The higher the drive rank dr, the greater the energy that drives the stepping motor 107. The stable number NS is a counter that is incremented for each step. The stepping motor control device 100 determines whether or not to change the drive rank dr by referring to the stable number NS.

(Step S213) After the power is turned on, the stepping motor control device 100 moves the gear one revolution (i.e., 360 [steps]) and identifies the position of the load tooth. After storing the position of the load tooth, the stepping motor control device 100 proceeds to step S215.
(Step S215) The stepping motor control device 100 judges whether or not the position of the loaded tooth is a stored one. If the position of the loaded tooth is a stored one (step 215; YES), the stepping motor control device 100 advances the process to step S217. If the position of the loaded tooth is not a stored one (step 215; NO), the stepping motor control device 100 advances the process to step S221.

(Step S217) The stepping motor control device 100 applies a swing pulse to the stepping motor 107.
(Step S219) The stepping motor control device 100 applies a drive pulse to the stepping motor 107.
That is, since the induced voltage cannot be obtained at the position of the loaded tooth, the drive rank is not controlled.

The stepping motor control device 100 performs the processes from step S221 to step S241 to control the drive rank dr, which is the rank of the drive pulse, based on the result of determining the induced voltage VRs of the normal teeth.
(Step S221) The stepping motor control device 100 applies a swing pulse to the stepping motor 107.
(Step S223) The stepping motor control device 100 judges whether the induced voltage VRs of the normal teeth is greater than a predetermined threshold value Vcomp. If the induced voltage VRs of the normal teeth is greater than the predetermined threshold value Vcomp (Step 223; YES), the stepping motor control device 100 advances the process to Step S225. If the induced voltage VRs of the normal teeth is equal to or less than the predetermined threshold value Vcomp (Step 223; NO), the stepping motor control device 100 advances the process to Step S235.

(Step S225) The stepping motor control device 100 determines whether or not the driving rank dr is 0. If the driving rank dr is 0 (Step 225; YES), the stepping motor control device 100 proceeds to step S233. If the driving rank dr is not 0 (Step 225; NO), the stepping motor control device 100 proceeds to step S227.
(Step S227) The stepping motor control device 100 increments the number of stable times NS by one.
(Step S229) The stepping motor control device 100 determines whether or not the stable number NS is 360. If the stable number NS is 360 (Step 229; YES), the stepping motor control device 100 proceeds to step S231. If the stable number NS is not 360 (Step 229; NO), the stepping motor control device 100 proceeds to step S233.

(Step S231) The stepping motor control device 100 subtracts 1 from the drive rank dr. That is, the stepping motor control device 100 drives the stepping motor 107 with smaller energy from the next time onwards. The stepping motor control device 100 sets the number of stable times NS to 0.
(Step S233) The stepping motor control device 100 maintains the drive rank dr.
(Step S235) The stepping motor control device 100 adds 1 to the drive rank dr. That is, the stepping motor control device 100 drives the stepping motor 107 with greater energy from the next time onwards. The stepping motor control device 100 sets the number of stable times NS to 0.
(Step S241) The stepping motor control device 100 applies a drive pulse to the stepping motor 107.

[Summary of Effects of the Sixth Embodiment]
According to the embodiment described above, the stepping motor control device 100 increases the rank of the drive pulse when the induced voltage Vrs is smaller than a predetermined threshold Vcomp by including the control circuit 103. That is, when the mechanical load on the rotor determined by the determination circuit 104 is smaller than a predetermined threshold, the control circuit 103 applies a drive pulse of a higher rank than the drive pulse applied immediately before, from among drive pulses of multiple ranks with different energy.
Furthermore, by including the control circuit 103, the stepping motor control device 100 reduces the rank of the drive pulse after the number of stable times NS has reached the number of revolutions of the gear when the induced voltage Vrs is greater than a predetermined threshold Vcomp. That is, when the mechanical load received by the rotor as determined by the determination circuit 104 to be greater than a predetermined threshold is obtained a predetermined number of times in succession, the control circuit 103 applies a drive pulse of a lower rank than the drive pulse applied immediately before, out of drive pulses of multiple ranks with different energies.

According to the embodiment described above, even if the load on the wheel train of the timepiece 1 becomes large, problems such as step-out can be prevented by controlling the energy driving the stepping motor 107 to be large.
In addition, when the energy of the drive pulse is reduced, the deflection is performed after determining the load for one revolution of the gear, thereby preventing problems such as loss of synchronism caused by erroneously reducing the energy of the drive pulse.

[Seventh embodiment]
Next, a seventh embodiment will be described. First, a problem to be solved by the stepping motor control device 100 according to the seventh embodiment will be described.
As described above, the oscillation pulse detects the mechanical load by oscillating the rotor. In particular, for a gear having normal teeth and loaded teeth, it is possible to determine whether the gear is meshing with the normal teeth or the loaded teeth by detecting the mechanical load. Here, if the energy of the oscillation pulse is too large, the rotor may oscillate even when it is meshing with the loaded teeth. Also, if the energy of the oscillation pulse is too small, the rotor may not oscillate even when it is meshing with the normal teeth. Therefore, it is required that the energy of the oscillation pulse is an appropriate energy. In this embodiment, the energy of the oscillation pulse is adjusted to an appropriate energy.

22 is a diagram for explaining the oscillation pulse rank control in the seventh embodiment. A series of operations of the stepping motor control device 100 according to the seventh embodiment will be described with reference to the same figure.
In this embodiment, the gears are assumed to have one load tooth each for the coarse adjustment gear and the fine adjustment gear. The description is based on the premise that the coarse adjustment gear rotates once in 360 steps, and the fine adjustment gear rotates once in 45 steps. In other words, while the coarse adjustment gear rotates once, the fine adjustment gear rotates eight times.
The process described in this embodiment is started when the power is turned on, and the control is repeated thereafter.

(Step S311) The stepping motor control device 100 sets the oscillation rank sr to 0, the number of needle movements ND to 0, and the number of loads NR to 0 as initial conditions. The oscillation rank sr indicates the rank of energy when the rotor is oscillated by an oscillation pulse. The higher the oscillation rank sr, the greater the energy. The number of needle movements ND is a counter that is incremented for each step. The number of needle movements ND differs from the stable number NS in that it includes both normal teeth and loaded teeth. The loaded number NR is the number of times a tooth is determined to be a loaded tooth during one revolution of the gear.

(Step S313) After the power is turned on, the stepping motor control device 100 rotates the gear one revolution (i.e., 360 [steps]) and identifies the position of the loaded tooth. After storing the position of the loaded tooth, the stepping motor control device 100 proceeds to step S315.
(Step S315) The stepping motor control device 100 determines whether or not the number of hand movements ND is 360. If the number of hand movements ND is 360 (Step 315; YES), the stepping motor control device 100 advances the process to step S331. If the number of hand movements ND is not 360 (Step 315; NO), the stepping motor control device 100 advances the process to step S317.
(Step S317) The stepping motor control device 100 applies a swing pulse to the stepping motor 107.

(Step S319) The stepping motor control device 100 determines whether the induced voltage VRs is greater than a predetermined threshold value Vcomp. If the induced voltage VRs is greater than the predetermined threshold value Vcomp (step 319; YES), the stepping motor control device 100 advances the process to step S323. If the induced voltage VRs is equal to or less than the predetermined threshold value Vcomp (step 319; NO), the stepping motor control device 100 advances the process to step S321.
(Step S321) The stepping motor control device 100 increments the load number NR. That is, the stepping motor control device 100 counts the number of times the tooth is determined to be a loaded tooth.

(Step S323) The stepping motor control device 100 applies a drive pulse to the stepping motor 107.
(Step S325) The stepping motor control device 100 increments the number of hand movements ND.

(Step S331) The stepping motor control device 100 judges whether the load count NR is greater than the maximum load count NRmax. If the load count NR is greater than the maximum load count NRmax (step 331; YES), the stepping motor control device 100 advances the process to step S341. If the load count NR is equal to or less than the maximum load count NRmax (step 331; NO), the stepping motor control device 100 advances the process to step S333.
(Step S333) The stepping motor control device 100 judges whether the load count NR is smaller than the minimum load count NRmin. If the load count NR is smaller than the minimum load count NRmin (Step 333; YES), the stepping motor control device 100 advances the process to Step S343. If the load count NR is equal to or greater than the minimum load count NRmin (Step 333; NO), the stepping motor control device 100 advances the process to Step S345.

The maximum load count NRmax is, for example, 28, and the minimum load count NRmin is, for example, 9. In this embodiment, since the fine adjustment gear rotates eight times while the coarse adjustment gear rotates once, at least nine loaded teeth are judged while the coarse adjustment gear rotates once (360 [steps]). Therefore, the minimum load count NRmin is set to 9. Also, since there are cases in which induced voltage is detected multiple times consecutively as a loaded tooth, the maximum load count NRmax is set to 28, assuming that about three detections are performed per tooth.
The numbers of maximum load cycles NRmax and minimum load cycles NRmin are arbitrary, and may be determined according to the number of steps of the load tooth gear, for example.

(Step S341) The stepping motor control device 100 adds 1 to the oscillation rank sr. That is, the stepping motor control device 100 applies an oscillation pulse with greater energy from the next time onwards.
(Step S343) The stepping motor control device 100 subtracts 1 from the oscillation rank sr. That is, the stepping motor control device 100 applies an oscillation pulse with smaller energy from the next time onwards.

(Step S345) The stepping motor control device 100 determines that the energy of the oscillation pulse is appropriate. The stepping motor control device 100 compares the detected load position with the load position stored in step S313.
(Step S351) If the detected position matches the stored position (step 351; YES), the stepping motor control device 100 advances the process to step S361. If the detected position does not match the stored position (step 351; NO), the stepping motor control device 100 advances the process to step S353.
(Step S353) The stepping motor control device 100 corrects the position of the load tooth from the stored position to the detected position.

(Step S361) The stepping motor control device 100 sets the number of needle movements ND and the number of loads NR to 0.

[Summary of Effects of Seventh Embodiment]
According to the above-described embodiment, the stepping motor control device 100 includes the control circuit 103, and controls the rank of the oscillation pulse based on the number of times that the gear is determined to be a loaded tooth during one rotation of the gear. That is, when a gear having loaded teeth rotates one revolution, the stepping motor control device 100 selects which rank of oscillation pulse to apply from among a plurality of ranks of oscillation pulses with different energy levels, based on the number of times that the determination circuit 104 determines that the mechanical load received by the rotor is greater than a predetermined threshold.

According to the embodiment described above, the stepping motor control device 100 can control the energy of the oscillation pulse to an appropriate energy even if the load on the wheel train of the timepiece 1 fluctuates. Therefore, according to this embodiment, the mechanical load can be accurately determined.

[Eighth embodiment]
Next, an eighth embodiment will be described. In the eighth embodiment, the process described in the sixth embodiment and the process described in the seventh embodiment are performed in combination. The process in the eighth embodiment will be described with reference to FIG. 23 .
23 is a diagram for explaining an example of a case where the drive pulse rank control and the oscillation pulse control in the eighth embodiment are combined. In the eighth embodiment, the same processes as those explained in the sixth embodiment and the seventh embodiment are denoted by the same reference numerals, and the explanation thereof may be omitted. The process explained in the sixth embodiment is described as step S200, and the process explained in the seventh embodiment is described as step S300.

(Step S411) The stepping motor control device 100 sets, as initial conditions, the oscillation rank sr to 0, the drive rank dr to 0, the number of hand movements ND to 0, the number of loads NR to 0, the number of stable times NS to 0, and the search S to 0. The eighth embodiment differs from the processes described in the sixth and seventh embodiments in that it has the search S.
While controlling the rank of the rocking pulse, it is not possible to know whether the needle is correctly aligned, so the drive pulse is not controlled. In other words, when controlling both the rank of the rocking pulse and the rank of the drive pulse, the search S serves as a flag indicating the period during which the rank of the rocking pulse is being controlled.

(Step S421) If the load position is not one of the stored positions, the stepping motor control device 100 determines whether or not Search S is 0. When Search S is 0, this indicates that the rank of the oscillation pulse has not been determined. When Search S is not 0 (i.e., Step S421; NO), the process proceeds to Step S319, and drive rank control is not performed. When Search S is 0 (i.e., Step S421; YES), the process proceeds to Step S223, and drive rank control is performed.

(Step S431) The stepping motor control device 100 increments the load count NR. That is, the stepping motor control device 100 counts the number of times the tooth is determined to be a loaded tooth. This is the same process as step S321 in the seventh embodiment.

The stepping motor control device 100 sets the search S in steps S451 to S455.
(Step S451) The stepping motor control device 100 sets a search S to 1.
(Step S453) The stepping motor control device 100 sets search S to 0.
(Step S455) The stepping motor control device 100 sets search S to 0.

[Summary of Effects of Eighth Embodiment]
According to the embodiment described above, the stepping motor control device 100 sets search S to 1 during the period in which it is controlling the rank of the oscillation pulse, and does not control the drive pulse when search S is 1. In other words, the stepping motor control device 100 does not control the drive pulse while it is controlling the rank of the oscillation pulse.
Therefore, according to the above-described embodiment, the stepping motor control device 100 can prevent a situation in which the rank of the drive pulse is erroneously determined while controlling the rank of the oscillation pulse.

All or part of the functions of the watch 1 described above may be recorded as a program on a computer-readable recording medium, and this program may be executed by a computer system. The computer system includes hardware such as an OS and peripheral devices. Examples of computer-readable recording media include portable media such as flexible disks, optical magnetic disks, ROMs (Read Only Memory), and CD-ROMs, storage devices such as hard disks built into computer systems, and volatile memory (Random Access Memory: RAM) provided on servers on networks such as the Internet. Volatile memory is an example of a recording medium that retains a program for a certain period of time.

The above-mentioned program may also be transmitted to another computer system via a transmission medium, for example, a network such as the Internet, or a communication line such as a telephone line.

The above program may also be a program that realizes all or part of the above-mentioned functions. Note that the program that realizes part of the above-mentioned functions may be a so-called differential program, which is a program that can realize the above-mentioned functions in combination with a program that is pre-recorded in the computer system.

The above describes an embodiment of the present invention with reference to the drawings, but the specific configuration is not limited to the above-described embodiment, and includes design modifications and the like that do not deviate from the gist of the present invention.

1...watch, 4...movement (watch movement), 6...hour hand (needle), 20A...first motor (stepping motor), 22...rotor, 30...first wheel train group (wheel train group), 34b...third hour intermediate pinion (first gear), 42a...24 hour gear (second gear), 61A...first standard teeth, 61B...second standard teeth, 62...load teeth, 62A...first load teeth, 100...stepping motor control device, 101...oscillating circuit, 102...frequency division circuit, 103...control circuit, 105...voltage detection circuit, 106...motor drive circuit, 107...stepping motor, 110...needle drive unit, 201...stator, 202...rotor, 203...rotor housing through hole, 204, 205...inner notch, 206, 207...outer notch, 208...magnetic core, 209...coil

Claims (21)

a driving unit that drives a stepping motor having a rotor that rotates the pointer and a coil that generates a magnetic flux for rotating the rotor;
a control unit that outputs a drive pulse for rotating the rotor and a swing pulse for swinging the rotor to the drive unit;
a voltage detection unit that detects an induced voltage generated in the coil when the rotor vibrates;
a determination unit that determines a mechanical load applied to the rotor based on a result detected by the voltage detection unit;
Equipped with
The control unit outputs the corresponding rocking pulse before outputting the drive pulse,
the determination unit determines the mechanical load based on a result of the voltage detection unit detecting the rotation caused by the output of the oscillation pulse.
Stepping motor control device. The control unit outputs the drive pulse after a predetermined period of time has elapsed after outputting the rocking pulse.
2. The stepping motor control device according to claim 1. the determination unit determines, as the mechanical load, whether a first gear that rotates based on rotation of the rotor is in contact with a loaded tooth of a second gear having a loaded tooth;
3. The stepping motor control device according to claim 1 or 2. The control unit controls energy for driving the stepping motor in accordance with the mechanical load determined by the determination unit.
The stepping motor control device according to any one of claims 1 to 3. The control unit controls an output time of the drive pulse to control energy for driving the stepping motor.
5. The stepping motor control device according to claim 4. The control unit controls an excitation method of the stepping motor to control energy for driving the stepping motor.
5. The stepping motor control device according to claim 4. The control unit controls a duty ratio of the drive pulse to control energy for driving the stepping motor.
5. The stepping motor control device according to claim 4. The control unit controls a voltage of the drive pulse to control energy for driving the stepping motor.
5. The stepping motor control device according to claim 4. The oscillation pulse is either a first oscillation pulse having energy for rotating the rotor in a first rotation direction and for oscillating the rotor, or a second oscillation pulse having energy for rotating the rotor in a second rotation direction after outputting the first oscillation pulse and for oscillating the rotor.
The stepping motor control device according to any one of claims 1 to 8. The first rotation direction is a forward rotation direction, and the second rotation direction is a direction opposite to the first rotation direction.
The stepping motor control device according to claim 9. The control unit outputs the first rocking pulse when the rocking pulse is output in accordance with a predetermined cycle in which the drive pulse is output, and outputs the first rocking pulse and the second rocking pulse when the rocking pulse is output at a predetermined timing that does not correspond to the predetermined cycle in which the drive pulse is output.
The stepping motor control device according to claim 10. the determination unit determines the mechanical load applied to the rotor based on whether or not a voltage value detected by the voltage detection unit exceeds a predetermined threshold.
The stepping motor control device according to any one of claims 1 to 11. the determination unit determines the mechanical load applied to the rotor based on whether or not a generation timing of the voltage value detected by the voltage detection unit is within a predetermined period.
The stepping motor control device according to any one of claims 1 to 12. The control unit has a rocking pulse output mode in which the rocking pulse is output, and a rocking pulse non-output mode in which the rocking pulse is not output.
The stepping motor control device according to any one of claims 1 to 13. the drive unit drives the stepping motor with a first voltage when the drive pulse is output from the control unit, and drives the stepping motor with a second voltage lower than the first voltage when the swing pulse is output from the control unit.
The stepping motor control device according to any one of claims 1 to 14. the control unit applies, when the mechanical load received by the rotor determined by the determination unit is smaller than a predetermined threshold, a drive pulse of a higher rank than the drive pulse applied immediately before, among the drive pulses of a plurality of ranks having different energies, and when the mechanical load received by the rotor determined by the determination unit is larger than the predetermined threshold a predetermined number of times in succession, applies, when the mechanical load received by the rotor determined by the determination unit is larger than the predetermined threshold, a drive pulse of a lower rank than the drive pulse applied immediately before, among the drive pulses of a plurality of ranks having different energies.
The stepping motor control device according to any one of claims 1 to 15. the control unit selects which rank of the oscillation pulse to apply from among the oscillation pulses of a plurality of ranks having different energy levels, based on the number of times that the determination unit determines that the mechanical load received by the rotor is greater than a predetermined threshold value when a gear having loaded teeth has made one revolution.
The stepping motor control device according to any one of claims 1 to 16. The control unit does not control the drive pulse while controlling the rank of the rocking pulse.
18. The stepping motor control device according to claim 17. A stepping motor control device according to any one of claims 1 to 18,
The stepping motor;
A movement equipped with. A watch equipped with the movement described in claim 19. a stepping motor including a rotor for rotating a pointer and a coil for generating a magnetic flux for rotating the rotor, wherein a drive pulse is applied to the stepping motor to rotate the rotor, and a swing pulse is applied to the stepping motor to swing the rotor;
detecting an induced voltage generated in the coil when the rotor vibrates;
determining a mechanical load applied to the rotor based on the detected result;
outputting the corresponding rocking pulse before outputting the driving pulse;
determining the mechanical load based on a result of the rotation caused by the output of the oscillation pulse detected by the voltage detection unit;
Stepping motor control method.