JP3306676B2 - Small electrical equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various small electric appliances such as a charging device, an electric toothbrush or an electric power tool, and more particularly, to a power supply main body for supplying electric power and an electric equipment main body having a load which can be separated from each other. The present invention relates to a device which is configured and capable of transferring power between the two devices using electromagnetic induction coupling.

[0002]

2. Description of the Related Art Conventionally, a small-sized electric device of this kind has a secondary battery on the device main body side, and always sets the device main body on the power supply main body side while maintaining the charged state of the secondary battery with a very small current. It was common to prepare for a short-time load drive by the device body alone. Therefore, while the primary-side oscillating unit such as the inverter circuit provided in the power supply main unit is always in the driving state, the load of the load is used for the purpose of exclusively saving power when the device main unit is removed from the power supply main unit for a long time. In some cases, the output of the primary oscillation unit is controlled in accordance with the presence or absence.

[0003]

However, in the above configuration, when the power that can be output from the primary side oscillating unit provided on the power supply main body side is increased, a metal piece such as a clip is used instead of the device main body. It has been found that even if the metal piece is disposed close to the primary coil, the metal piece may be erroneously recognized as an appropriate load and an excessive eddy current may flow to generate heat.

The present invention has been made in view of the above-mentioned inconveniences, and accurately detects a mounting state of a power supply main body to a power supply main body to prevent a heat generation accident in which a foreign substance is mistaken for the equipment main body. It is an object of the present invention to provide a small electric device that can be used.

[0005]

As shown in FIG. 1, a small electric apparatus according to the present invention comprises a power supply body 16 having a primary side oscillating section 14, a primary coil 50 of the primary side oscillating section 14, and electromagnetic induction. The device body 24 having the load 20 supplied with power via the coupled output coil 74 is connected to the contact surfaces 34 and 35.
And can be detachably attached to each other via the.

Further, the contact surface 3 on the device main body 24 side described above.
An operation piece 96 is formed on the power supply body 16 at a corresponding position on the contact surface 34 while an operation hole 94 is formed in the operation piece 96. The switching element 90 is switched in conjunction with the insertion of the switching element 96, and is provided with a switching element 90 that enables control to increase the output of the primary side oscillation section 14 from an off state or a sufficiently suppressed state.

The above-described primary coil 50 on the power supply main body 16 side
Is formed in an air-core shape having the center axis coincident with the operation hole 94 formed on the contact surface 34, and the switching element 90 is disposed corresponding to the inner bottom of the operation hole 94. The operation piece 96 extending from the 24 side can use the distal end portion of the core 84 that penetrates the output coil 74 and fits into the primary coil 50 when attached to the power supply main body 16.

[0008]

With the configuration described above, when the device main body 24 is detached from the power supply main body 16, the state in which the output of the primary side oscillation section 14 is turned off or sufficiently suppressed by the switching element 90 is maintained. .

Here, when the main body 24 is properly mounted on the power supply main body 16, the contact pieces 34 and 35 coincide with each other, and at the same time, the operation piece 96 is fitted into the operation hole 94 to switch the switching element 90. At the same time, the primary oscillation unit 1
The output from 4 is controlled to increase, and power is supplied to the load 20 via the primary coil 50 and the output coil 74.

[0010]

According to the present invention, as described above, the primary side oscillator 14
Since the switching element 90 that enables the output control of the power supply body 16 is provided on the power supply main body 16 side and the switching element 90 is switched by the operation piece on the equipment main body 24 side, the mounting of the equipment main body 24 to the power supply main body 16 is possible. Accurate determination is made, thereby preventing an accident in which the metal piece is mistakenly recognized as the load 20 and generates heat.

Further, by forming the operation piece 96 for switching the switching element 90 with the core 84 of the output coil 74, the overall structure can be simplified, and the coupling between the primary coil 50 and the output coil 74 and the primary side Oscillator 1
4 is surely performed at the same time.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example in which the present invention is applied to a charging device for a secondary battery will be described below. However, the present invention is not limited to this, and it goes without saying that the present invention can be applied to various small electric devices such as an electric toothbrush and an electric tool. .

FIGS. 1 to 4 show a charging device embodying the present invention.
As shown in FIG. 1, a protection circuit 12 and an inverter 1
And a lower end thereof detachably fitted to the power supply main body 16, and into a main body case 18 using a charging current sent from the power supply main body 16. And a device main body 24 capable of charging the secondary battery 20a provided as the load 20.

The main body case 10 of the power supply body 16 is a rectangular hollow box as shown in FIG. 3, and a power supply cord 30 having a power supply plug 28 is extended from the side surface 26 to the end thereof. Can be connected to the commercial AC power supply 32. Further, a contact surface 34 with the device main body 24 is provided on the upper surface side,
The side surface 26 is extended upward so as to surround the contact surface 34 and form a receiving portion 36 into which the lower end of the device main body 24 is removably fitted.

The protection circuit 1 housed in the main body case 10
2, a large current input is prevented by a metal film resistor 38 connected in series with a power supply line to the inverter circuit 15 as shown in FIG. 4, while a surge voltage is input by an overvoltage absorption element 40 connected in parallel. To prevent. After the input voltage is further rectified by the rectifier 42, the temperature fuse 4
4 allows the operation of the inverter circuit 15 to be forcibly stopped at the time of overheating, and the capacitor 46 prevents noise from flowing out from the inverter circuit 15 side.

The inverter circuit 15 includes a primary coil 50 on the collector side of the switching transistor 48, a protection resistor 52 on the emitter side, and an output control unit 54 and an output limiting unit 56 on the base side. ing.

The output control unit 54 is formed by connecting a resistor 58, a capacitor 60 and a feedback coil 62 in series. The ON / OFF cycle of the switching transistor 48 is set to, for example, about 40 kHz by the charging / discharging time constant of the resistor 58 and the capacitor 60. On the other hand, the switching transistor 48 is controlled by the feedback coil 62 and the capacitor 60.
The on-time is regulated.

That is, the capacitor 6 is connected via the resistor 58.
When 0 is charged and the base voltage of the switching transistor 48 exceeds a set value, a collector current starts to flow through the primary coil 50, and the increase in the collector current generates a voltage in a direction of turning on the transistor 48 in the feedback coil 62. The transistor 48 is turned on rapidly.
After the transistor 48 is turned on, charging and discharging of the capacitor 60 progresses, and the direction of the voltage output from the feedback coil 62 is reversed due to the decrease in the base current. Turn off sharply. Transistor 4 described above
By repeating the on / off operation of No. 8, the inverter circuit 15 performs self-excited oscillation at a predetermined frequency.

The capacitor 64 connected in parallel with the primary coil 50 absorbs a shock voltage generated when the transistor 48 is turned off. Transistor 4
The protection resistor 52 interposed on the emitter side of the transistor 8 controls the off-time of the transistor 48 by increasing the emitter potential of the transistor 48 in response to the increase of the collector current, so that an excessive current flows into the transistor 48. It is to prevent that.

The output limiting section 56 is provided with the feedback coil 6 described above.
A capacitor 66 is connected in parallel with the capacitor 2, and a Zener diode 68 is connected in series with the capacitor 66. Here, the feedback coil 62 and the capacitor 66
A diode 70 that enables charging only during the off period of the switching transistor 48 is interposed between the zener diode 68 and the capacitor 66.
The transistor 72 is turned on by the base voltage during the ON period of the transistor 48, and discharges the capacitor 72 in a direction in which the capacitor 66 can be discharged.
Are interposed.

Therefore, the charging voltage of the capacitor 66 charged by the feedback coil 62 during the off period of the transistor 48 is caused by poor regulation characteristics of the inverter transformer composed of the primary coil 50 and the output coil 74. The charging voltage increases as the load current drawn from the inverter circuit 15 decreases, and this charging voltage is added to the base voltage in a direction in which the Zener diode 68 is turned on. As a result, the Zener diode 68 is turned on at a lower base voltage than during normal charging, and the base current is shunted to reduce the on-time of the transistor 48. In this case, the power consumption of the inverter circuit 15 can be limited as much as possible.

The power signal having a frequency sufficiently higher than the commercial frequency generated by the inverter circuit 15 as described above is
After the voltage is reduced to the charging voltage by the output coil 74 of the device main body 24 which is electromagnetically coupled to the primary coil 50, half-wave components are selectively supplied to the secondary battery 22 a by the diode 76 to perform charging.

The device main body 24 accommodates a plurality of secondary batteries 20a such as NiCd batteries in an upper portion of a hollow main body case 18 having a rectangular cross section, and a secondary battery 20a in a lower portion of the main body case 18. An output coil 74 for supplying a predetermined charging current to 20a is provided, and a plug 80 for supplying power from the secondary battery 22 to an external load 78 such as a motor is provided on the upper surface side.

The output coil 74 is wound around a coil bobbin 82 disposed substantially at the center of the contact surface 35.
Further, a thin rod-shaped core 84 made of a ferromagnetic material such as ferrite is provided through the bobbin 82,
The tip of the core 84 is projected downward from the contact surface 35.

On the other hand, on the contact surface 34 of the main body case 10 on the power supply main body 16 side, an insertion hole 86 into which the core 84 is inserted is formed corresponding to the projecting position of the core 84. Further, the coil bobbin 88 is fixed so that the insertion hole 86 is aligned with the central axis, and the primary coil 50 is wound on the coil bobbin 88.

Therefore, as shown in FIG.
When the main body 24 and the device main body 24 are properly mounted with the contact surfaces 34 and 35 coincident with each other, the output coil 74 and the primary coil 50 are fitted on the same core 84, so that the primary coil 50 and the output coil Between the output coils 74, a predetermined voltage is induced across the output coil 74 in response to a change in current in the primary coil 50. The induced voltage is selectively extracted by the rectifying diode 76 from the voltage generated during the off-period of the switching transistor 48 of the inverter circuit 15 and sent to the secondary battery 20a for charging.

The present invention has the above-described configuration, and has a feature in an on / off structure of the inverter circuit 15 by the switching element 90 provided on the power supply main body 16 side.

That is, as shown in FIG. 4, a normally open first switching element 90a is provided between the resistor 58 and the base end of the transistor 48, and a normally closed second switching element 90b is provided between the base end and the emitter end of the transistor 48. By providing each of them, the operation of the inverter circuit 15 can be forcibly stopped unless the ON / OFF states of both switching elements 90 are simultaneously inverted.

Further, the first switching element 90a is fixed to the back side of the contact surface 34, and the second switching element 90b is fixed to the bottom of the primary coil 50 so as to be in contact with the wall surface of the main body case 10, respectively. An operation hole 94 having a diameter as small as possible so as not to allow a fingertip to enter at least is provided in the main body case 10 so as to correspond to the projecting position of the pressing piece 92 that enables the switching operation of the switch contact in each switching element 90 at times.

On the other hand, a first operation piece 96a fitted into the operation hole 94a of the first switching element 90a is provided from the contact surface 35 on the device body 24 side, and an operation hole 94b of the second switching element 90b is provided from the tip of the core 84. Second operation piece 96 that fits
b are each formed to protrude.

Therefore, the power supply main body 16 is connected to the equipment main body 24.
Is correctly set, the first and second operation pieces 96 are simultaneously fitted in the operation holes 94, and the pressing pieces 92 in the operation holes 94 are pushed to push the first and second switching elements 90.
Of the inverter circuit 15 at the same time.
Is driven.

The switching element 90 is not limited to the push type, but can be changed as appropriate, such as a slide type and a bayonet type. The number and position of the switching elements 90 can also be changed arbitrarily. In addition, the interposition position of the switching element 90 in the inverter circuit 15 can be changed as long as the operation of the inverter circuit 15 can be controlled, such as by turning on / off the energization of the inverter circuit 15.

Furthermore, the switching element 90 can be switched in a plurality of stages, and the output voltage from the inverter circuit 15 can be changed by changing the bias voltage of the inverter circuit 15 in conjunction with the switching operation of the switching element 90. It can itself be changed in multiple stages. Similarly, a plurality of switching elements 90 may be provided, and different switching elements 90 may be operated for each device body 24 to be mounted, and the output of the inverter circuit 15 may be controlled in accordance with the switching.

Further, the shapes and coupling states of the primary coil 50 and the output coil 74 can be appropriately changed as long as electromagnetic induction coupling can be performed. For example, it is possible to change the arrangement position or the direction of the core or to increase the oscillation frequency in the inverter circuit 15 so that the coil is formed in a printed shape and the core itself is eliminated.

The configuration of the inverter circuit 15 is not particularly limited. For example, the inverter circuit 15 is of a separately-excited type provided with an oscillator for turning on and off the switching transistor 48 instead of the self-excited type as described above. Further, as the primary side oscillation unit 14, instead of the one using the inverter circuit 15 as described above, one using the frequency of the commercial AC power supply 32 as it is may be used.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of the present invention, and shows a state in which a device main body is removed from a power supply main body.

FIG. 2 is an explanatory diagram showing a state in which the device main body in FIG. 1 is mounted on a power supply main body.

FIG. 3 is a partially broken perspective view showing an example in which the present invention is applied to a charging device.

FIG. 4 is an electric circuit diagram of the charging device.

[Explanation of symbols]

 14 Primary Oscillator 15 Inverter Circuit 16 Power Supply Body 20 Load (Secondary Battery) 24 Equipment Main Body 34 Contact Surface on Power Supply Body 35 Contact Surface on Equipment Main Body 50 Primary Coil 56 Output Restrictor 84 Core 86 Insertion Hole 90 Switching element 92 Pressing piece 94 Operation hole 96 Operation piece

──────────────────────────────────────────────────の Continued on the front page (72) Inventor Mitsuo Yamanaka 4680 Ikata, Ogata-machi, Fagawa-gun, Fukuoka Prefecture Inside Kyushu Hitachi Maxell Co., Ltd. Kyushu Hitachi Maxell, Ltd. (72) Inventor Eiji Sakata 4680, Ikata, Fukuoka, Tagawa-gun, Fukuoka Prefecture Inside Kyushu Hitachi Maxell, Inc. (56) References JP-A-4-217824 (JP, A) −138840 (JP, U) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H02J ^7/ 00-7/12 H02J ⁷ /34-7/36

Claims (1)

(57) [Claims] 1. A power supply body (16) having a primary-side oscillating section (14), and a primary coil (5) having a primary-side oscillating section (14).
0) and the device body (24) provided with the load (20) supplied with power via the output coil (74) that is electromagnetically inductively coupled to each other via the contact surfaces (34) and (35). with a freely attachable, on one of protruding operating piece (96) on the contact surface of the device body (24) side (35), said power supply body (16) side of the abutment surface (34) the corresponding position, the conjunction operation piece (96) is provided an operation hole (94) which fits is deep inside of the operating hole (94), inserting operation with conjunction with switching to the primary side oscillation of the operation piece (96) A switching element (9) capable of controlling to increase the output of the section (14) from an off state or a sufficiently suppressed state.
0) , wherein the primary coil (50) of the power supply body (16) is
The operation hole (94) formed on the contact surface (34) and the middle
It is an air-core shape with the center axes aligned, and the back of the operation hole (94).
The switching element (90) is provided corresponding to the bottom.
On the other hand, the operation piece (96) extending from the device body (24) side
Penetrates the output coil (74), and
When mounted on the power supply body (16), the primary coil (5
A small electric device, which is a tip portion of a core (84) that fits into (0) .