JPH0919078A - Electromagnetic induction charger, electronic device to be charged and electrically moving toothbrush - Google Patents

Abstract

PURPOSE: To reduce loss and power consumption in a charger, by using a resonance converter for self-excited oscillation, and generating a high-frequency field from an excitation coil through the resonance current. CONSTITUTION: A push-pull resonance-type converter 22 is used to carry out self-excited oscillation, and the resonance current is carried at an excitation coil 23 to generate a high-frequency sine-wave field from the excitation coil 23. Then, an induced voltage is caused at a power receiving coil 11 through electromagnetic induction, and a secondary battery 13 for driving a motor is charged by a charging circuit 12. The resonance-type converter 22 has a small loss, and power consumption of a charger 2 is made small. At the same time, a transistor and an FET as active elements for driving the resonance-type converter 22 have also a small loss, and thereby these elements and the charger can be made small at low manufacturing cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic induction type charging device and an electronic device to be charged such as an electric toothbrush using the electromagnetic induction type charging device.

[0002]

2. Description of the Related Art Generally, many electric toothbrushes are equipped with a charging device, and from this charging device, a secondary battery of the toothbrush body is charged using electromagnetic induction. As a charging device for an electric toothbrush of this type, a self-excited LC oscillation type oscillator such as Colpitts or Hartley is conventionally used to oscillate an AC signal using a DC voltage obtained by rectifying an AC voltage by a rectifier circuit as a power source. Alternatively, a pulse oscillator such as a blocking oscillator is used.

Further, as shown in FIG. 11A, the conventional rechargeable electric toothbrush is provided with an exciting coil 53 in a charging device main body 51, and the same number of toothbrush main bodies 52 as the exciting coils 53 are charged. What you get, or Figure 1
As shown in FIG. 1 (b), there is one in which the charging device main body 51 is provided with one exciting coil, and this one exciting coil can simultaneously charge a plurality of toothbrush main bodies 52.

As shown in FIG. 12, the conventional electromagnetic induction type charging device and the toothbrush main body are provided with a charger main body 51 having a built-in exciting coil 53, and a power receiving coil 55 is provided above the exciting coil 53. The built-in toothbrush main body 52 is placed and charging is performed by electromagnetic induction. Regarding electromagnetic coupling, there are an air-core type as shown in FIG. 12A and a bar-shaped core 56 provided as in FIG. 12B.

As shown in FIG. 13, the power receiving coil 55 of the conventional electric toothbrush body uses a coil formed by winding conductive wires.

[0006]

The above-mentioned conventional non-contact charging type electric toothbrush charging device using a self-excited LC oscillator such as Colpitts or Hartley causes a substantial loss in the charging circuit. , Inefficient, power consumption is high. In addition, there is a problem that an active element (transistor, FET) for driving the circuit tends to be large. In addition, the one using a pulse oscillation type oscillator is likely to generate harmonic noise, and due to this harmonic noise, it is difficult to increase the frequency and it is difficult to downsize the reactance element (coil, capacitor). There's a problem.

The invention according to claim 1 of the present application was made in view of the above problems, and provides an electromagnetic induction type charging device which consumes less power, is small in size, and is low in cost. Is intended. Further, in the above-described conventional electromagnetic induction charging device, since the exciting coils are driven by the same number of exciting coils in the same phase, or are charged simultaneously by one large exciting coil, the generated excitation There is a problem that the radiation space of the magnetic flux becomes large, and radiation interference noise and power line noise are generated.

The invention according to claim 2 has been made in view of the above problems, and an object thereof is to provide an electromagnetic induction type charging device in which radiation interference noise and power line noise are less likely to occur. Further, in the above-described conventional electromagnetic induction charging device that uses an air-core coil or a coil having a rod-shaped core as the exciting coil, the coupling coefficient of the coil is small, so that the power transmission efficiency is poor. Since the radiation space of the generated magnetic flux is large, radiation interference noise and noise induced in the power supply line are large. Since the radiating space of the generated magnetic flux is large, the charging current is reduced, the power consumption is increased, and the oscillation frequency of the excitation circuit fluctuates or stops due to the influence of the metal body around the charger. This phenomenon is likely to occur especially when the charger is placed on a metal plate. There are problems such as.

The invention according to claim 3 is made by paying attention to the above-mentioned problems, and is an electromagnetic induction type charging device which has a good power transmission efficiency, a small noise, and is hardly influenced by a surrounding metal body. Is intended to provide. Also,
Since the power receiving coil of the electronic device to be charged such as the above-described conventional electric toothbrush also uses the air core coil or the rod-shaped core, the coupling coefficient of the coil is small, so that the power transmission efficiency is poor. Also, because the radiation noise is large,
There is a problem that it is difficult to increase the power and a large charging current cannot be obtained.

The invention according to claim 4 has been made in view of the above problems, and an object thereof is to provide an electronic device to be charged which has a high power transmission efficiency during charging and a small radiation interference noise. There is. Further, in the above-described conventional electronic device to be charged, such as an electric toothbrush, which uses a winding of a conductive wire as a power receiving coil, the coil has a winding structure and thus has a size in the axial direction. The body becomes longer and the weight becomes heavier. Due to the winding structure, the inductance value is not constant, which causes variations in the charging current. Mass production is poor due to the winding structure, and the manufacturing cost of the coil is high. There are problems such as.

The invention according to claim 5 has been made in view of the above problems, and an object thereof is to provide a charged electronic device which is lightweight, compact, excellent in mass productivity, and low in cost.

[0012]

SUMMARY OF THE INVENTION An electromagnetic induction charging device according to the claims and claim 1 of the present application includes a rectifier circuit for converting an AC voltage into a DC voltage and a DC rectifying circuit for receiving the DC voltage. A resonance type converter for exciting and oscillating, and an excitation coil for applying a high frequency magnetic field to a device to be charged by supplying a resonance current of the resonance type converter.

In this charging device, a resonant converter is used to perform self-excited oscillation, and the resonant current flows through the exciting coil to generate a high-frequency magnetic field. This high-frequency magnetic field is linked to the power receiving coil of the electronic device to be charged and charged by electromagnetic induction. The electromagnetic induction charging device according to claim 2 converts an AC voltage into a DC voltage, oscillates an oscillation circuit by using this DC voltage as a power source, and applies an oscillating current to a plurality of exciting coils to charge a device to be charged. In a battery for charging a secondary battery, the adjacent exciting coils are driven so that the polarities thereof are opposite to each other.

In this charging device, since the exciting coils adjacent to each other have opposite polarities, they cancel each other, so that radiation interference noise and power line noise are less likely to occur. Claim 3
The electromagnetic induction charging device according to the first aspect converts an AC voltage into a DC voltage, oscillates an oscillation circuit by using this DC voltage as a power source, and applies an oscillating current to an exciting coil to charge the device to be charged.
In a rechargeable battery, the exciting coil is wound around an E-shaped or T-shaped core in cross section.

In this charging device, since the exciting coil is wound around the E-shaped or T-shaped core in cross section, when a charged electronic device such as an electric toothbrush is set, the coupling coefficient between the exciting coil and the receiving coil is large. Becomes The charged electronic device according to claim 4 includes a power receiving coil that receives a high-frequency magnetic field from an exciting coil of an electromagnetic induction type charging device, and charges a secondary battery by a voltage induced in the power receiving coil. The power receiving coil is wound around an E-shaped or T-shaped core in cross section.

In this electronic device to be charged, the power receiving coil is
Since it is wound around the E-shaped or T-shaped core in cross section, the coupling coefficient between the exciting coil and the power receiving coil becomes large when set in the charging device. The electronic device to be charged according to claim 5 is
A power receiving coil that receives a high-frequency magnetic field from an exciting coil of an electromagnetic induction charging device, and a secondary battery is charged by a voltage induced in the power receiving coil. The power receiving coil is formed on a substrate. It is composed of print patterns.

In this electronic device to be charged, since the power receiving coil is composed of the printed pattern formed on the substrate, the power receiving coil becomes thin, and the body of the electronic device to be charged is shortened and lightened accordingly.

[0018]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a block diagram showing the configuration of an electric toothbrush according to an embodiment (embodiment of claim 1) of the present invention. The electric toothbrush of this embodiment includes a toothbrush body 1 and a charger 2. The charger 2 is a commercial power source 3
A rectifier circuit 21 for rectifying an AC voltage from the rectifier to convert it into a DC voltage, a resonant converter 22 for self-oscillating a high frequency by using the DC voltage as a power source, and a high frequency sine wave magnetic field generated by flowing a resonant current. And an exciting coil 23. The toothbrush body 1 includes a power receiving coil 11 that induces a voltage by a sinusoidal magnetic field from the exciting coil 23, a charging circuit 12 that converts the induced voltage into a DC voltage, and a secondary battery 13 that is charged by the charging circuit 12. Is equipped with. A motor (not shown) is driven by the voltage of the secondary voltage 13.

2 and 3 are connection diagrams showing specific circuits of the resonance type converter of the charger 1 for the electric toothbrush of the above embodiment. In the circuit of FIG. 2, a coil L ₀ and a capacitor C ₀ are connected in parallel, and a transistor Q is connected in parallel to this parallel circuit.
A series circuit of ₁ and Q ₂ is connected. Transistor Q
The bases of ₁ and Q ₂ are connected to the negative input terminal of the DC input via resistors R ₁ and R ₂ , respectively. The base of the transistor Q ₁ is composed of a capacitor C ₁ and a resistor R ₃
Is connected to the collector of the transistor Q ₂ through the parallel circuit of the capacitor Q _{2 and} the base of the transistor Q ₂ is connected to the capacitor C ₂
And a resistor R _{4 connected} in parallel to the collector of the transistor Q ₁ . Also, the transistors Q ₁ and Q
_{The two} emitters are commonly connected and connected to the negative input terminal of the DC input. The + input terminal of DC input is coil L
It is connected via ₁ to the intermediate connection point of the coil L ₀ . In FIG. 3, FETs are used instead of the transistors Q ₁ and Q _2.
It uses Q ₁ and Q ₂ .

The circuits shown in FIGS. 2 and 3 are both push-pull resonance type converters, and the feedback voltage is divided by a parallel circuit of resistors R ₁ , R ₃ and C ₁ ,
The circuit has a high breakdown voltage and can be used with a high power supply voltage. In the electric toothbrush of FIG. 1, this circuit uses this push-pull resonance type converter as the converter 22 to perform self-excited oscillation, and the resonance current is passed through the exciting coil 23 to generate a high-frequency sinusoidal magnetic field from the exciting coil 23. Generated, an induced voltage is generated in the power receiving coil 11 by electromagnetic induction, and the charging circuit 12 causes the secondary battery 13 for driving the motor.
To charge. The resonant converter has low loss and the charger consumes less power. Further, since the loss of the transistors and FETs that are active elements for driving the resonance converter is small, it is possible to realize miniaturization and cost reduction of these elements and the charger.

FIG. 4 is a diagram showing the relationship between the toothbrush body of the electric toothbrush of the embodiment and the charger. (A) of FIG.
The charger 2 is provided with two exciting coils 23 so that the two toothbrush bodies 1 can be charged. Further, in FIG. 4B, the charger 2 is provided with four exciting coils 23 so that the four electric toothbrushes can be charged. In the figure, arrows orthogonal to each exciting coil 23 indicate
The polarity of the magnetic field is shown, and both are set so that the adjacent exciting coils have opposite polarities.

The electromagnetic fields leaking from the charger 2 are canceled by the adjacent exciting coils, so that radiation interference noise and power line noise are less likely to occur. 5 and 6 are diagrams showing an exciting coil of the charger of the electric toothbrush of the embodiment. In FIG. 5, in the charger 2, the magnetic core 24 having an E-shaped cross section is shown.
The exciting coil 23 is wound around the. Further, in FIG. 6, in the charger 2, the exciting coil 23 is wound around the magnetic core 24 having a T-shaped cross section. 25 and 26 are metal plates which are assumed to exist in the surroundings. The broken line with an arrow indicates the magnetic flux.

In both cases of FIG. 5 and FIG. 6, since the magnetic flux is intensively generated in the vicinity of the coil from the end face of the core, the leakage magnetic flux is small and the coupling coefficient is large. Since the magnetic flux distribution range is small, noise is unlikely to occur. Further, since the magnetic flux interlinking with the surrounding metal body is small, the oscillation of the charger is stable and the loss is small. In particular, since there is no magnetic flux generated from the bottom surface of the charger, there is no influence when the charger is placed on the metal plate 25.

FIG. 7 is a diagram showing another example of the charging coil of the toothbrush body of the electric toothbrush of the embodiment. In this embodiment, the power receiving coil 11 in the toothbrush body 1 is wound around the magnetic core 14 having an E-shaped cross section. This E-shaped core 14
As a result, the magnetic flux from the exciting coil 23 is linked to the power receiving coil 11 without leakage, and the coupling coefficient becomes large. Even if only the power receiving coil 11 is wound around the E-shaped core, the effect is large.
Similarly, if 3 is wound around the E-shaped magnetic core 24, the coupling coefficient of the coil is further increased.

FIG. 8 shows an example in which the magnetic core having an E-shaped cross section in FIG. 7 is changed to a magnetic core having a T-shaped cross section, and substantially the same effect as that of FIG. 7 can be obtained. FIG. 9 is a schematic view showing the inside of the toothbrush body of the electric toothbrush of the embodiment. In FIG. 9, the power receiving coil 1 is provided inside the toothbrush body 1.
The power receiving coil 11 includes primary and secondary batteries 13 and a motor 15, and the power receiving coil 11 is configured by a print pattern formed on the front and back of a thin substrate 16. 10A and 10C show patterns on the front and back sides of the power receiving coil 11, and FIG. 10B shows a side view.

In this embodiment, since the coil is thin, the toothbrush body can be shortened and the weight can be reduced. Since it is a printed circuit board, it has good reproducibility and there is little variation in charging current. Since it is a printed circuit board, mass productivity is good and cost reduction is possible.

[0027]

According to the first aspect of the present invention, the resonance type converter is used for self-excited oscillation and the resonance current is used to generate a high frequency electromagnetic field from the exciting coil. Due to the converter, the loss is small and the power consumption of the charging device is small. Driving active element (transistor,
FET) loss is small, so miniaturization of these elements,
Cost can be reduced. Since a sinusoidal magnetic field is used, radiation interference noise and harmonic noise given to the power supply line are small. Since the high frequency is used, the reactance elements (coil, capacitor) of the charging device and the electronic device to be charged can be downsized. The number of parts is small, the charging device itself is small,
Can be constructed at low cost. The effect is obtained.

According to the second aspect of the invention, the charging device is provided with a plurality of exciting coils, and the adjacent exciting coils are driven so as to have opposite polarities. Therefore, the electromagnetic field leaking from the charging device is prevented. Since adjacent exciting coils cancel each other, it is possible to obtain an effect that radiation interference noise and power line noise are less likely to occur. Further, according to the invention of claim 3, since the exciting coil of the charging device is wound around the core made of a magnetic material and having an E-shaped or T-shaped cross-sectional shape, the coupling coefficient of the coil increases, Power transmission efficiency is improved. Since the magnetic flux is intensively generated in the vicinity of the core, radiation interference noise and noise induced in the power supply line are small. It is unlikely to be affected by the metal body around the charging device, and malfunction due to this is unlikely to occur. In particular, even when the charging device is placed on the metal plate, there is no hindrance to the operation. The effect is obtained.

Further, according to the invention of claim 4, since the power receiving coil of the main body of the electronic device to be charged is wound around the E-shaped or T-shaped core, the coupling coefficient of the coil is increased and the power transmission efficiency is increased. Will get better. Further, since the radiation space of the exciting magnetic flux is small, radiation interference noise is less likely to occur. By carrying out the inventions according to claims 3 and 4 individually or in combination, it is possible to easily increase the electric power, and it is possible to obtain a large charging current in the secondary battery in the toothbrush body. It will be possible to charge the battery. The effect is obtained.

Further, according to the invention of claim 5, since the power receiving coil of the electronic device to be charged is composed of the print pattern coil, the coil is thin, so that the toothbrush body can be shortened and the weight can be reduced. Since it is a printed circuit board, it has good reproducibility and there is little variation in charging current. Since it is a printed circuit board, mass productivity is good and cost reduction is possible. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an electric toothbrush according to an embodiment of the present invention.

FIG. 2 is a connection diagram showing a circuit example of a resonance converter used in the electric toothbrush charger of the embodiment.

FIG. 3 is a connection diagram showing another circuit example of the resonant converter used in the electric toothbrush charger of the embodiment.

FIG. 4 is a diagram illustrating a charger and a toothbrush body of an electric toothbrush according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating an exciting coil of a charger for an electric toothbrush according to another embodiment of the present invention.

FIG. 6 is a diagram illustrating an exciting coil of a charger for an electric toothbrush according to still another embodiment of the present invention.

FIG. 7 is a diagram illustrating a power receiving coil of a toothbrush body of an electric toothbrush according to still another embodiment of the present invention.

FIG. 8 is a diagram illustrating a power receiving coil of an electric toothbrush body according to still another embodiment of the present invention.

FIG. 9 is a schematic view illustrating an internal structure of a toothbrush body of an electric toothbrush according to another embodiment of the present invention.

FIG. 10 is a diagram for explaining a power receiving coil of the electric toothbrush body of the embodiment.

FIG. 11 is a diagram illustrating a conventional electric toothbrush with a charger.

FIG. 12 is a diagram illustrating a coupling state between an exciting coil and a power receiving coil of a conventional electric toothbrush.

FIG. 13 is a diagram illustrating an internal structure of a toothbrush body of a conventional electric toothbrush.

[Explanation of symbols]

 1 Toothbrush main body 2 Charger 11 Power receiving coil 21 Rectifier circuit 22 Resonant converter 23 Excitation coil

Claims (6)

[Claims] 1. A rectifier circuit for converting an AC voltage into a DC voltage, a resonance type converter for receiving the DC voltage and performing self-excited oscillation, and a resonance current flowing through the resonance type converter to charge a device to be charged. An electromagnetic induction charging device comprising: an exciting coil for applying a high-frequency magnetic field. 2. An electromagnetic wave for converting an AC voltage into a DC voltage, oscillating an oscillating circuit using the DC voltage as a power source, and supplying an oscillating current to a plurality of exciting coils to charge a secondary battery of a device to be charged. In the induction charging device, the electromagnetic induction charging device is characterized in that the exciting coils that are adjacent to each other are driven so that the polarities thereof are opposite to each other. 3. An electromagnetic induction system for converting an AC voltage into a DC voltage, oscillating an oscillating circuit using this DC voltage as a power source, and supplying an oscillating current to an exciting coil to charge a secondary battery of a device to be charged. The charging device is an electromagnetic induction charging device, wherein the exciting coil is wound around an E-shaped or T-shaped core in cross section. 4. An electronic device to be charged, comprising a power receiving coil for receiving a high frequency magnetic field from an exciting coil of an electromagnetic induction type charging device, and charging a secondary battery with a voltage induced in the power receiving coil. An electronic device to be charged, wherein the electronic device is wound around an E-shaped or T-shaped core in cross section. 5. An electronic device to be charged, comprising a power receiving coil for receiving a high frequency magnetic field from an exciting coil of an electromagnetic induction type charging device, and charging a secondary battery with a voltage induced in the power receiving coil. Is a printed pattern formed on a substrate. 6. An electric toothbrush provided with the electromagnetic induction charging device according to claim 1, claim 2, or claim 3, wherein the secondary battery of the toothbrush body is charged from the charging device.