JP2003319564A - Small-sized electric apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To positively inform users of a drop of the remaining battery voltage. <P>SOLUTION: This small-sized electric apparatus, equipped with a motor 1 operating a primary battery or a secondary battery 2 as a power supply, includes a detection means 4 for detecting the remaining battery voltage. A driving circuit 3 for driving the motor 1 performs motor driving in a driving mode for remaining-battery voltage drop display with short motor driving stop inserted during stationary driving of the motor by the detection of a remaining- battery voltage drop with the detection means 4. Thus, the users can recognize the remaining-battery voltage drop from the driving change. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small electric device equipped with a motor that operates using a primary battery or a secondary battery as a power source, and more particularly to a small electric device such as an electric toothbrush that is used while being held by hand. Is.

[0002]

2. Description of the Related Art There are various types of small electric devices for driving a motor by a primary battery or a secondary battery, but in those controlling the driving of the motor to operate at a specific frequency, There are the following problems.

That is, in the case of a normal DC motor, the driving torque is gradually reduced with the decrease of the battery remaining amount and the driving is stopped, so that the user can recognize the decrease of the battery remaining amount. If the drive is controlled to operate at a specific frequency, the operation of the motor hardly changes even when the battery level decreases, and the drive stops at the same time as the battery level runs out. If you try, you can not grasp the remaining battery level at all.

For this reason, in the case where the battery remaining amount cannot be grasped from the change in the operation of the motor, a battery remaining amount detecting means is provided and the battery remaining amount is detected according to the battery remaining amount detected by the battery remaining amount detecting means. The battery level is displayed on the battery level indicator. For example, one or more light emitting diodes are provided as a remaining amount display section, and lighting / blinking of the light emitting diodes is controlled according to the remaining battery amount estimated from the battery voltage, the load current, the elapsed time of use, and the like. .

[0005]

However, a small electric device is constructed so that it can be used near the face by holding it like an electric toothbrush and can be operated without looking at the operation portion when the switch is turned on and off. In the case of a device that has a battery, it is difficult for the user to check if the display on the battery level indicator changes during use. There are many people who notice that there is nothing. In this case, the remaining amount display section, which is an additional component in terms of the function of the electric toothbrush, does not fulfill its role and merely increases the cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small-sized electric device capable of surely notifying a user of a decrease in battery remaining amount.

[0007]

SUMMARY OF THE INVENTION The present invention, however, provides a small electric device equipped with a motor which operates by using a primary battery or a secondary battery as a power source, and is provided with a battery residual amount detecting means for driving the motor. The drive circuit of 1 drives the motor in the low battery level display drive mode in which the motor drive is stopped for a short time during the steady drive of the motor by the detection of the low battery level by the detection means.
It has the characteristics of

Further, the drive circuit is driven at a frequency different from the frequency during steady driving within the human audible frequency band by the detection of the low battery level by the detecting means, and the low battery level display drive mode. The second feature is that the motor is driven by.

Further, the drive circuit drives the motor in the low battery level display drive mode in which the pulse width of the drive pulse for driving the motor is gradually reduced by the detection of the low battery level detected by the detecting means. There is a third feature in some cases.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to an example of an embodiment. In the illustrated small-sized electric device, a secondary battery 2 is used as a power source and a linear reciprocating motion in an axial direction is performed on an output shaft 3. This is an electric toothbrush having a built-in linear vibration type motor 1, and a toothbrush (not shown) is detachably attached to the tip of the output shaft 15.

The motor 1 has a vibrator 13 in which the output shaft 15 is integrally connected and is made of a permanent magnet.
, The coil 11 arranged on the outer periphery of the vibrator 13, and the output shaft 3
The balance weight 14 that penetrates is housed in the case 10,
Further, the spring 12 is provided 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 surface of the case 10, respectively.
The oscillator 13 and the output shaft 15 are caused to reciprocally vibrate in the axial direction by applying a pulsed alternating current to the coil 11. At this time, the oscillator 13 and the balance weight 14 are movable. By supplying a pulsed alternating current in the vicinity of the mechanical resonance frequency determined by the mass of the member, the reciprocating motion is vibrated in the resonance state.

FIG. 1 shows a circuit block. In the figure, 20 is a charging transformer for non-contact power supply, 21 is a charging block, a booster circuit 30, a drive pulse generating circuit 31, and an amplifier 3
And a drive circuit 3 for driving the motor 1 configured by
Is provided with a detecting means 4 for detecting the remaining amount of the secondary battery 2 from the voltage or load current of the secondary battery 2 or the operating time. The drive pulse generating circuit 31 outputs the motor by the output of the detecting means 4. The drive pulse supplied to 2 is changed.

FIG. 3 (a) shows the reciprocating motion of the output shaft 3 during steady driving at the mechanical resonance frequency. At this time, the reciprocating motion waveform (see FIG. 3 ( A voltage called a counter electromotive voltage is generated with a phase delayed by a half wavelength from a)), as shown in FIG. 3 (b). 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.

However, the drive pulse generating circuit 31 is
When the remaining battery level detected by the detecting means 4 becomes less than a predetermined value, as shown in FIG. 4 (a), the drive pulse supply for steady drive and some continuous drive pulses are eliminated, and the motor is removed. The state shifts to the low battery level display drive mode in which the state in which the drive is stopped for 2 in a short time is repeated. The user can recognize the decrease in the remaining battery level from the change in the driving state during use.

FIG. 5 shows another example. When the battery level is low, a drive pulse (FIG. 5 (b)) having a different frequency from the drive pulse in normal operation (FIG. 5 (a)) is supplied to the motor 2. Further, the drive pulse in the low battery level display mode is set to a frequency within the audible frequency band. The driving pulse at regular times is also in the audible frequency band, but the sound generated by the slight vibration of the air at the vibration frequency associated with driving causes the battery level to drop and the battery level drop display drive mode to be entered. The user can recognize the decrease in the remaining battery level during the use because it changes (shifts to the high-pitched sound side in the illustrated example) when it is performed.

FIG. 6 shows still another example. Here, when the battery level is low, the drive pulse generation circuit 31 shifts to the battery level drop display drive mode in which the pulse width is gradually narrowed at appropriate time intervals as shown in FIG. 6B. Is done. If the steady drive is continued, as shown in FIG. 6 (a), the drive pulse supply is stopped and the drive is immediately stopped at the time t when the battery level becomes empty, but the drive is gradually stopped before that. In order to bring them closer, the user can recognize that the battery level is going to stop from the end.

The case where the motor 1 is a linear vibration motor is shown here, but it goes without saying that any motor may be used as long as it operates by the supply of drive pulses.

[0018]

As described above, according to the first aspect of the present invention, the motor drive in the low battery level display drive mode in which the detection of the low battery level causes a short motor drive stop during the steady drive of the motor. Therefore, the user can recognize the battery remaining amount only by the drive change of the motor without providing the display unit for displaying the remaining amount.

According to the second aspect of the present invention, in the low battery level display drive mode, when the low battery level is detected, driving is performed within the human audible frequency band and at a frequency different from the frequency during steady driving. Since the motor is driven, the user can recognize the degree of remaining battery level by an audible sound without providing a display section for displaying the remaining amount.

Further, according to the third aspect of the invention, since the motor is driven in the low battery level display drive mode in which the pulse width of the drive pulse for driving the motor is gradually reduced when the low battery level is detected, it is used. The person can recognize that the driving stop is not due to a failure or the like, but is due to the fact that the battery level is exhausted.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an example of an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an example of the above motor.

FIG. 3 is an explanatory diagram of a state during steady driving of the above.

FIG. 4 is an explanatory diagram of a state when the remaining battery level is reduced in the above.

FIG. 5 is an explanatory diagram of a drive pulse at the time of steady drive and a drive 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 drive and a drive pulse at the time of low battery level according to another example.

[Explanation of symbols]

1 motor 2 batteries 3 drive circuit 4 Detection means

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Seiichi Iwao             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F term (reference) 2G016 CB12 CC06 CC09 CC12 CE07                       CF07                 5G003 BA01 DA02 EA05                 5H030 AA00 AS12 FF41 FF52 FF68

Claims (3)

[Claims] 1. A small electric device including a motor that operates using a primary battery or a secondary battery as a power source, and a battery residual amount detecting means is provided, and a drive circuit for driving the motor has a battery residual amount by the detecting means. A small electric device characterized in that the motor is driven in a low battery level display drive mode in which the motor drive is stopped for a short time during the steady drive of the motor by detecting the decrease in the amount. 2. A small electric device equipped with a motor that operates using a primary battery or a secondary battery as a power source, further comprising a battery residual amount detecting means, and the drive circuit for driving the motor is a battery based on the detecting means. Small size characterized by driving the motor in the low battery level display drive mode, which is driven at a frequency different from the frequency in steady driving within the human audible frequency band when the low level is detected. Electrical equipment. 3. A small electric device comprising a motor that operates using a primary battery or a secondary battery as a power source, and a battery residual amount detecting means is provided, and the drive circuit for driving the motor is provided by the detecting means. A small electric device characterized in that a motor is driven in a low battery level display drive mode in which a pulse width of a drive pulse for driving the motor is gradually reduced by detecting a low battery level.