JP3826835B2 - Small electrical equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small electric device including a motor that operates using a primary battery or a secondary battery as a power source, and more particularly to a small electric device that is used in a state of being gripped by hand, such as an electric toothbrush.
[0002]
[Prior art]
There are various types of small electric devices that drive a motor by a primary battery or a secondary battery. However, in the case of controlling the driving of the motor to operate at a specific frequency, the following problems occur. There is.
[0003]
In other words, in the case of a normal DC motor, the driving torque gradually decreases as the remaining battery level decreases, and the driving stops, so that the user can grasp the decrease in the remaining battery level. If the drive is controlled so that it operates, the motor operation will hardly change even if the remaining battery level decreases, and the drive will stop as soon as the remaining battery level runs out. If this is the case, the remaining battery level cannot be grasped at all.
[0004]
For this reason, in the case where the remaining battery level cannot be grasped from the change in the operation of the motor, a remaining battery level detection unit is provided, and the remaining battery level is determined according to the remaining battery level detected by the remaining battery level detection unit. The remaining amount is displayed on the display unit. For example, one or more light emitting diodes are provided as a remaining amount display unit, and lighting and blinking of the light emitting diodes are controlled in accordance with the remaining amount of the battery estimated from the battery voltage, load current, usage time, and the like. .
[0005]
[Problems to be solved by the invention]
However, in the case of a device that is configured so that a small electric device can be held near the face by hand, such as an electric toothbrush, and can be operated without looking at the operation part even when the switch is turned on and off, it remains in use. Even if the amount display changes, it is difficult for the user to confirm it, and it is often noticed that the battery is exhausted only when the battery is exhausted and cannot be used. . In this case, the remaining amount display portion, which is an additional component in terms of the function of the electric toothbrush, does not fulfill its role and merely increases the cost.
[0006]
The present invention has been made in view of these points, and an object of the present invention is to provide a small electric device that can reliably notify the user of a decrease in the remaining battery level.
[0007]
[Means for Solving the Problems]
Accordingly, the present invention provides a small electric apparatus including a motor that operates using a primary battery or a secondary battery as a power source, and includes a battery remaining amount detection unit, and a drive circuit for driving the motor is a battery that uses the detection unit. The first feature is that the motor drive is performed in the drive mode for displaying the battery remaining amount with a short stop of the motor driving during the steady driving of the motor by detecting the remaining amount of the battery.
[0008]
In addition, the drive circuit drives the motor in a drive mode for displaying a low battery level that is driven at a frequency different from the frequency at the time of steady driving by detecting the low battery level by the detecting means. It has the 2nd characteristic that it performs.
[0009]
Further, the drive circuit performs the motor drive in the battery remaining amount lowering display driving mode in which the pulse width of the driving pulse for driving the motor is gradually reduced by detecting the remaining battery amount by the detecting means. It has the third feature.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on an example of an embodiment. A small electric device in the illustrated example is a linear vibration motor 1 in which a secondary battery 2 is used as a power source and an output shaft 3 performs a linear reciprocating motion in an axial direction. The toothbrush (not shown) is detachably attached to the tip of the output shaft 15.
[0011]
In the motor 1, the output shaft 15 is integrally connected and a vibrator 13 formed of a permanent magnet, a coil 11 disposed on the outer periphery of the vibrator 13, and a balance weight 14 through which the output shaft 3 passes. It is housed in the case 10, and further between one end of the vibrator 13 and the inner surface of the case 10, between the other end of the vibrator 13 and one end of the balance weight 14, and between the other end of the balance weight 14 and the inner face of the case 10. The springs 12 are arranged between them, and the vibrator 13 and the output shaft 15 are caused to reciprocate in the axial direction by passing a pulsed alternating current through the coil 11. By supplying a pulsed alternating current in the vicinity of the mechanical resonance frequency determined by the mass of the movable member such as the balance weight 14, the reciprocating motion is made a vibration in a resonance state.
[0012]
FIG. 1 shows a circuit block. In the figure, 20 is a charging transformer for non-contact power feeding, 21 is a charging block, and the driving circuit 3 for driving the motor 1, which is composed of a booster circuit 30, a driving pulse generating circuit 31, and an amplifier 32, is secondary. A detection means 4 for detecting the remaining amount of the secondary battery 2 from the voltage, load current, or usage time of the battery 2 is provided. The drive pulse generation circuit 31 supplies the motor 2 with the output of the detection means 4. Change the drive pulse.
[0013]
FIG. 3 (a) shows the reciprocating motion of the output shaft 3 during steady driving at a mechanical resonance frequency. At this time, the reciprocating motion waveform (FIG. 3 (a)) A voltage called a counter electromotive voltage as shown in FIG. The drive pulse generation circuit 31 supplies a drive pulse as shown in FIG. 3C to the motor 2 with an appropriate phase difference at the timing when the back electromotive voltage crosses the 0V line.
[0014]
However, when the remaining battery level detected by the detection means 4 becomes a predetermined value or less, the drive pulse generation circuit 31 performs continuous drive drive pulse supply and continuous drive as shown in FIG. The operation shifts to the battery remaining low display drive mode in which several drive pulses are eliminated and the motor 2 is stopped for a short time. For the user, it is possible to recognize a decrease in the remaining battery level from the change in the driving state during use.
[0015]
FIG. 5 shows another example. When the remaining battery level decreases, a drive pulse (FIG. 5 (b)) having a frequency different from that of the steady drive pulse (FIG. 5 (a)) is supplied to the motor 2. Further, the drive pulse in the drive mode for low battery level display is set to a frequency within the audible frequency band. The steady driving pulse is also in the audible frequency band, but the sound generated by the slight vibration of the air at the vibration frequency associated with the driving shifts to the driving mode for low battery level display. Change (shifted to the high-pitched sound side in the illustrated example), the user can recognize a decrease in the remaining battery level during use.
[0016]
Another example is shown in FIG. Here, when the remaining battery level is reduced, the drive pulse generation circuit 31 shifts to the remaining battery level display driving mode in which the pulse width is gradually reduced at an appropriate time interval as shown in FIG. 6B. It is like that. If steady driving is continued, as shown in FIG. 6 (a), the supply of driving pulses stops and stops immediately at the time t when the remaining battery level becomes empty, but the driving is gradually stopped before that. In order to approach, the user can recognize that the remaining battery level is moving from the end to the stop.
[0017]
Although the case where the motor 1 is a linear vibration motor is shown here, it is needless to say that the motor 1 may be any motor as long as it operates by supplying drive pulses.
[0018]
【The invention's effect】
As described above, in the first aspect of the present invention, the motor driving is performed in the driving mode for displaying the remaining battery level with a short stop of the motor driving during the steady driving of the motor by detecting the remaining battery level. Even without providing a display for displaying the remaining amount, the user can recognize the remaining amount of the battery only by changing the driving of the motor.
[0019]
According to a second aspect of the present invention, the motor driving in the driving mode for displaying the low battery level is performed when the low battery level is detected, and the driving is performed within the human audible frequency band and at a frequency different from the frequency during steady driving. Therefore, the user can recognize the remaining battery level by an audible sound without providing a display unit for displaying the remaining amount.
[0020]
Further, in the invention of claim 3, since the motor driving is performed in the driving mode for displaying the remaining battery level which gradually decreases the pulse width of the driving pulse for driving the motor when the remaining battery level is detected, the user drives It can be recognized that the stop is not due to a failure or the like, but due to the remaining battery level being exhausted.
[Brief description of the drawings]
FIG. 1 is a block circuit diagram of an example of an embodiment of the present invention.
FIG. 2 is a sectional view of an example of the motor.
FIG. 3 is an explanatory diagram of a state during steady driving as described above.
FIG. 4 is an explanatory diagram of a state when the remaining battery level is reduced.
FIG. 5 is an explanatory diagram of a driving pulse at the time of steady driving and a driving pulse at the time of low battery level in another example.
FIG. 6 is an explanatory diagram of a drive pulse at the time of steady driving and a drive pulse at the time of remaining battery charge in another example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor 2 Battery 3 Drive circuit 4 Detection means

Claims (3)

In a small electric device having a motor that operates using a primary battery or a secondary battery as a power source, the battery is provided with a battery remaining amount detecting means, and the drive circuit for driving the motor is detected by the detection means detecting a decrease in the remaining battery level. A small electric device characterized in that the motor is driven in a drive mode for low battery level display that sandwiches a short stop of the motor drive during a steady drive of the motor. In a small electric device having a motor that operates using a primary battery or a secondary battery as a power source, the battery is provided with a battery remaining amount detecting means, and the drive circuit for driving the motor detects a decrease in the remaining battery level by the detecting means. Thus, the small electric device is characterized in that the motor is driven in a drive mode for displaying a low battery level, which is driven at a frequency different from the frequency during steady driving within a human audible frequency band. In a small electric device including a motor that operates using a primary battery or a secondary battery as a power source, the battery further includes a battery remaining amount detection unit, and the drive circuit for driving the motor reduces a remaining battery level by the detection unit. A small electric device characterized in that, by detection, the motor is driven in a drive mode for low battery level display that gradually decreases the pulse width of the drive pulse for driving the motor.

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