JP2003114287A - Sweep motor for clock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a low power consumption without degrading the starting property of a sweep motor. SOLUTION: This sweep motor is provided with a sweep motor sweepingly driving with a driving pulse outputted from a driving circuit and a gear train for decelerating and transmitting the rotation of the sweep motor. In the driving pulse, a driving pulse P1 at the time of starting the sweep motor is set at a driving pulse with a wider pulse duration than that of a driving pulse P2 at the time of normally driving the sweep motor. For example, the driving pulse P1 at the time of starting is set at duty 100% for at least over one second, and the driving pulse P2 at the time of normal driving is set at a constant pulse duration at duty of less than 100%, for example, at duty 50%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a timepiece sweep motor.

[0002]

2. Description of the Related Art Conventionally, as a motor for driving a decoration of a timepiece, a sweep motor capable of normal rotation and reverse rotation by the same drive pulse is sometimes used. For example, two terminals each having a rotatable rotor and connected to both ends of a drive coil of a drive circuit built in the machine body are alternately driven to High every 62.5 ms, as shown by a drive pulse P10 shown in FIG.
In general, the driving force is applied to the rotor by switching between / Low and constantly passing a current in either direction (a pulse signal of 8 Hz and a duty of 100%).

On the other hand, recently, the number of windings of the drive coil is reduced for the purpose of cost reduction and low power consumption of the motor, and the duty is reduced for the purpose of low power consumption like the drive pulse P20 shown in FIG. One that lowers (8 Hz, pulse signal with 50% duty) has also appeared.

[0004]

However, if the number of windings of the drive coil is simply reduced or the duty is reduced as in the drive pulse P20 of FIG. 6, the current and power flowing through the coil are reduced, and the power is turned on or reset. It has a drawback that the start-up time after that is longer than necessary and the startability deteriorates. On the contrary, when the driving pulse P10 shown in FIG. 5 is driven at a duty of 100%, the startability is good but the low power consumption cannot be achieved. That is, as shown in the graph of FIG. 7, when the pulse width is sufficiently long and is 50 ms or more, the driving voltage is about 1 v, but when the pulse width is shortened and the duty is reduced, the pulse width is 30 ms. It can be understood from the fact that the driving voltage of 1.5 v, which is 1.5 times, is required.

Therefore, the present invention achieves low power consumption without deteriorating the startability.

[0006]

A timepiece sweep motor according to the present invention comprises a sweep motor that is driven by a drive pulse output from a drive circuit to sweep, and a train wheel that decelerates and transmits the rotation of the sweep motor. However, the drive pulse is set to a drive pulse having a wider pulse width than the drive pulse during the normal drive of the sweep motor when the sweep motor is started.
With this configuration, the sweep motor can be surely started at the time of start, and after the start, the sweep motor can be driven with low power consumption.

The drive pulse at the time of starting is at least 1
It is preferably set so as to be supplied for more than one second. During this time, the sweep motor can be reliably started.

Further, it is preferable that the drive pulse at the time of starting is set to a duty of 100%, and the drive pulse at the time of the normal drive is set to a constant pulse width with a duty of less than 100%.

Further, the drive pulse at the time of starting is set to a duty of 100%, and the drive pulse is a drive pulse having a duty of 100% at the time of starting to a drive pulse having a duty of less than 100% at the time of normal driving. Until,
It is preferably set so as to gradually change.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Regarding one embodiment of the present invention,
It will be described with reference to the drawings. FIG. 1 is a block diagram of an example in which the sweep motor of the present invention is used in a timepiece having a rotary ornament. A drive signal is supplied to the sweep motor M from the drive circuit D built in the timepiece machine body, and the train wheel G is rotated by the drive of the motor, and the rotary ornament O is oscillated. FIG. 2 shows the structure of the timepiece mechanical body. The lower case 1 and the upper case (not shown) are connected by a connecting means such as a patching stopper.
A wheel train G from the sweep motor M to the output vehicle is formed inside the lower case 1 and the upper case, and each gear of the wheel train G is axially supported by the lower case 1 and the upper case. The sweep motor M is a motor that is self-started by the drive pulse output from the drive circuit D, but the rotation direction is not constant, and either the forward rotation start or the reverse rotation start is performed depending on the timing of the start or other reasons. Is also a rotatable motor. The sweep motor M includes a stator 2a, a rotor 2b located between magnetic poles of the stator 2a, and a drive coil 2c wound around the stator 2a.

In the structure of the train wheel G, the drive gear 3 is provided integrally with the rotor 2b, and the rotation speed of the drive gear 3 is 3/10.
The 2nd wheel 4 that slows down to 2, the 3rd wheel 5 that slows down the rotation speed of the 2nd wheel 4 to 1/6, and the output wheel 6 that slows down the rotation speed of the 3rd wheel 5 to 2/15 It constitutes a reduction gear train. An output shaft 6a integral with the output wheel 6 projects from the upper case, and a rotary ornament O (not shown) is fixed to the tip of the output shaft 6a.

The natural frequency of this sweep motor M is
It is determined by the magnetic strength of the rotor magnet, the inertia of the entire rotor, and the size and shape of the stator, and is 8 Hz for this motor. Drive circuit D to drive coil 2
The drive pulse output to c causes the rotor 2b to start sweep rotation. As described above, the rotation direction of the rotor may be either forward or reverse at this time, but the rotation speed of the rotor 2b is 8 Hz = 480 rpm, and the output shaft 6a rotates at 3.2 rpm.

The drive pulse output to the drive coil 2c will be described below. Once the battery is turned on or the reset button is pressed to stop the motor,
As shown in FIG. 3, the pulse width is 6 for 1 second immediately after the restart.
A 2.5 ms pulse is applied to the drive coil 2c of the motor by switching the polarity every 62.5 ms. That is, the drive pulse P1 at the time of startup is output for 1 second with a duty of 100%.

The sweep motor M increases the inertia of the rotor 2b in order to smoothly and continuously operate the rotor 2b,
A drive pulse having a frequency corresponding to the natural frequency of the rotor 2b (near 8 Hz) is input at 8 Hz for driving. For this reason, at the time of start-up, the swinging movement starts around the static stable position of the rotor 2b, the amplitude gradually increases, and eventually the rotation movement starts. In the sweep motor M of this example, since the specifications of the drive coil and the like are adjusted so as to start the rotational motion at the second and third reciprocations at the time of startup, an average of 0.125 seconds to
The rotational movement starts in 0.25 seconds, but even if it is difficult to start due to variation, the rotational movement starts within 1 second. Therefore, the sweep motor M starts the sweep rotation while the drive pulse having the duty of 100% and the pulse width of 62.5 ms is output for 1 second.

As shown in FIG. 3, after 1 second, the pulse width is changed to 31.25 ms so that a non-energization time of 31.25 ms is allowed until the next pulse of the opposite polarity is output. To That is, the duty is 50% after 1 second.
Drive pulse P2 during the normal drive of the motor drive coil 2
applied to c. That is, the sweep motor M is driven with a large pulse width with a duty of 100% for the first 1 second after the reset, and 1 second after the sweep motor M surely enters the rotational movement, a short pulse width with a duty of 50%. The sweep motor M is driven by and the power consumption is kept low.

In the above example, the duty is 100.
% Drive pulse is output for 1 second, but the present invention is not limited to this and may be 1 second or more. The first one again
Although the duty is 100% for the second, the drive pulse P1 at the time of startup is not limited to the duty 100%, and if the pulse width is set to be longer than the pulse width of the drive pulse P2 at the time of normal drive after 1 second, There is a corresponding effect.

FIG. 4 is an example of another drive pulse, and FIG.
In the drive pulse of, the duty 100% of the drive pulse P1 at the time of start-up is suddenly switched to the duty 50% of the drive pulse P2 at the time of normal drive, but the present invention is not limited to this, and the duty may be gradually changed. Good. That is, the duty is set to 100% for the first 1 second, the duty is gradually decreased, and the gradually changing drive pulse P3 for about 1 second is used as the drive pulse of the pulse width correction period. % Drive pulse P during normal drive
You may enter 2.

[0018]

As described above, according to the present invention, the drive pulse of the sweep motor is set such that the drive pulse at the time of start-up is wider than the drive pulse at the time of normal drive. The sweep motor can be surely started, and after the start, the sweep motor can be driven with low power consumption. By supplying the drive pulse at the time of startup for at least 1 second or more, the sweep motor can be reliably started during this period. Since the duty is set to gradually change from 100% at the time of startup to less than 100% at the time of normal driving, the change smoothly moves and smooth driving is possible.

[Brief description of drawings]

FIG. 1 is a block diagram of a timepiece showing an embodiment of the invention.

FIG. 2 is a plan view of the timepiece mechanical body with an upper case removed.

FIG. 3 is a waveform diagram showing an example of drive pulses of the drive circuit of the present invention.

FIG. 4 is a waveform diagram showing another example of drive pulses of the drive circuit of the present invention.

FIG. 5 is a waveform diagram showing an example of drive pulses of a conventional drive circuit.

FIG. 6 is a waveform diagram showing another example of drive pulses of a conventional drive circuit.

FIG. 7 is a graph showing a relationship between a starting voltage and a pulse width.

[Explanation of symbols]

M sweep motor G train Drive pulse at P1 startup P2 Drive pulse during normal drive P3 Drive pulse that changes gradually

Claims (4)

[Claims] 1. A sweep motor that sweeps and drives by a drive pulse output from a drive circuit, and a train wheel that decelerates and transmits the rotation of the sweep motor. The drive pulse is provided when the sweep motor is started. ,
A sweep motor for a timepiece, wherein a drive pulse having a pulse width wider than that of a drive pulse of the sweep motor during normal driving is set. 2. The timepiece sweep motor according to claim 1, wherein the drive pulse at the time of starting is set to be supplied for at least 1 second or longer. 3. The drive pulse at the time of starting is set to a duty of 100%, and the drive pulse at the time of the normal drive is set to a duty of 100%.
Sweep motor for a watch characterized by being set to a constant pulse width of less than%. 4. The drive pulse at the time of starting is set to a duty of 100%, and the drive pulse is duty 100 at the time of starting.
% Drive pulse to duty 100 at the time of the normal drive
A sweep motor for a watch, which is set to gradually change up to a drive pulse of less than%.