JPH06311659A - Miniature electric appliance - Google Patents

Abstract

PURPOSE:To prevent heating accident due to erroneous recognition of a foreign matter located closely to a power supply body as an appliance body by providing means for removing a matter different from the appliance body on the contact face on the power supply body side. CONSTITUTION:When a foreign matter, e.g. a metal piece, is mounted on a contact face 22 on the power supply body 12 side, a foreign matter removing means 26 equipped with an active constitution, e.g. a locking mechanism, formed on the contact face 22 functions to slip off the foreign matter from the contact face 22. When an appliance body 20 is loaded to the power supply body 12 through contact faces 22, 24, the removing means 26 on the power supply body 12 side recognizes the appliance body 20 effectively. Consequently, a primary coil 14 is coupled properly with an output coil 16 to feed required power from the power supply body 12 side to a load 18 on the appliance body 20 side. Since a foreign matter, e.g. a metal piece, mounted inadvertently on the power supply body 12 side is immediately slipped down on the contact face 22, heating of the foreign matter due to application with magnetic field is prevented.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, a small electric device of this type is provided with a secondary battery on the device body side, and the device body is always mounted on the power source body side to maintain a charged state of the secondary battery with a small current,
It was general to prepare for load driving for a short time by the device body alone. Therefore, while the primary side oscillation unit such as the inverter circuit provided in the power supply body is always in the drive state,
For the purpose of exclusively saving power when the device body is removed from the power supply body for a long time, the output of the primary side oscillating section is also controlled depending on the presence or absence of a load.

[0003]

However, in the above configuration, when the power that can be output from the primary side oscillating section 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 placed close to the primary coil, the metal piece may be mistaken for a proper load and an excessive eddy current may flow to generate heat.

As a result of consideration made in view of such inconvenience, the present inventors have found that even if the primary side oscillating portion in the power source body is kept in a standby state while always being driven, the peripheral surface position on the power source body side is Is it difficult to ride something different from the main body of the device?
It has been found that the above-mentioned inconveniences can be solved all at once by constructing such a configuration that even if it is forcibly placed, it is immediately removed.

The present invention has been made on the basis of the above-mentioned findings, and it is an object of the present invention to provide a small electric device capable of preventing a heat generation accident in which a foreign substance placed close to a power supply main body is mistakenly recognized as a device main body. To aim.

[0006]

A small electric device according to the present invention has a general structure as shown in FIG.
For the power supply main body 12 including the primary side oscillating section 10 such as an inverter circuit, the primary coil 14 of the primary side oscillating section 10 is provided.
A device main body 20 having a load 18 such as a secondary battery, which is supplied with power via an output coil 16 electromagnetically coupled with, is detachably mountable.

In such a structure, the power source body 1 described above
It is characterized in that the contact surface 22 on the second side is provided with a means 26 for allowing an object different from the device body 20 to be removed from the contact surface 22.

As shown in FIG. 2, the above-mentioned removing means 26 can be constituted by a protruding portion 28 formed over substantially the entire contact surface 22 on the power source body 12 side. Further, the primary coil 14 and the output coil 16 described above are individually provided with the cores 30 and 32, and the both end surfaces 90 and 92 of the cores 30 and 32 are connected to the contact surface 2 of the power source body 12 and the device body 20.
It is preferable to dispose them separately from each other on 2 · 24.

[0009]

As described above, when a foreign object such as a metal piece is placed on the contact surface 22 on the power source body 12 side, a passive structure such as a protrusion 28 formed on the contact surface 22 or The foreign matter removing means 26 having an active structure such as a rocking mechanism works,
The foreign matter is slid off from the contact surface 22.

On the other hand, the main body 20 of the device is different from the main body 12 of the power supply.
Is attached via the contact surfaces 22 and 24, the power supply body 12
The removal means 26 on the side effectively determines the device body 20, and the primary coil 14 and the output coil 16 are properly coupled to each other to supply the necessary power from the power supply body 12 side to the load 18 on the device body 20 side. .

[0011]

As described above, according to the present invention, since the foreign matter removing means 26 is provided on the contact surface 22 on the power source body 12 side, even if a foreign matter such as a metal piece is accidentally placed on the power source body 12 side. The foreign matter is immediately slid off from the contact surface 22, and it is possible to prevent the foreign matter from flowing a magnetic field to generate heat.

[0012]

EXAMPLE An example in which the present invention is applied to the rechargeable battery charging device shown in FIGS. 2 to 4 is shown below, but the present invention is not limited to this, and it is also applicable to various small electric devices such as electric toothbrushes and electric tools. Of course, the same can be done.

The charging device embodying the present invention has an inverter type power supply main body 12 as shown in FIG.
And the lower end of which is detachably fitted to the power supply main body 12, and the secondary battery 34 inside can be charged by using the charging current sent from the power supply main body 12 using electromagnetic induction coupling. Composed of and.

The electric circuit constituting the charging device has a commercial AC power source input through a power source plug 38 extending from the main body case 36 of the power source main body 12 to the outside, as specifically illustrated in FIG. 40 is connected to the inverter circuit 11 via the protection circuit 42.

The protection circuit 42 blocks the input of a large current by the metal film resistor 44 connected in series with the power supply line to the inverter circuit 11, while preventing the input of the surge voltage by the overvoltage absorbing element 46 connected in parallel. To do.
Further, after the input voltage is rectified by the rectifier 48, the operation of the inverter circuit 11 at the time of overheating can be forcibly stopped by the temperature fuse 50, and the outflow of noise from the inverter circuit 11 side is prevented by the capacitor 52. There is.

The inverter circuit 11 includes a primary coil 14 on the collector side of the switching transistor 54, a protective resistor 56 on the emitter side, and an output control section 58 and an output limiting section 60 on the base side. ing.

The output control unit 58 is composed of a resistor 62, a capacitor 64 and a feedback coil 66 connected in series. The on / off cycle of the switching transistor 54 is set to, for example, about 40 kHz depending on the charging / discharging time constant of the resistor 62 and the capacitor 64. While regulating, the feedback coil 66 and the capacitor 64 make the switching transistor 54
The on-time of is regulated.

That is, the capacitor 6 is connected via the resistor 62.
4 is charged, and when the base voltage of the switching transistor 54 exceeds a set value, collector current begins to flow in the primary coil 14, and the increase in the collector current generates a voltage in a direction to turn on the transistor 54 in the feedback coil 66. Then, the transistor 54 is rapidly turned on.
After the transistor 54 is turned on, charging and discharging of the capacitor 64 progresses, and the base current decreases, so that the direction of the voltage output from the feedback coil 66 is reversed, and a reverse bias is applied between the base and emitter of the transistor 54 to cause the transistor 54 Turn off rapidly. Transistor 5 mentioned above
By repeating the on / off operation of No. 4, the inverter circuit 11 performs self-excited oscillation at a predetermined frequency.

The capacitor 68 connected in parallel with the primary coil 14 absorbs a shock voltage generated when the transistor 54 is turned off. Also transistor 5
The protection resistor 56 provided on the emitter side of 4 controls the off time of the transistor 54 by raising the emitter potential of the transistor 54 in response to the increase of the collector current, and an excessive current flows into the transistor 54. It is to prevent it.

The output limiting section 60 includes the feedback coil 6 described above.
A capacitor 70 is connected in parallel with the capacitor 6, and a zener diode 72 is connected in series with the capacitor 70. Here, the feedback coil 66 and the capacitor 70
A diode 74, which enables charging only during the off period of the switching transistor 54, is interposed between the two, and between the Zener diode 72 and the capacitor 70,
During the ON period of the transistor 54, the diode 76 is turned on by the base voltage to allow the capacitor 70 to be discharged.
Are installed respectively.

Therefore, the charging voltage of the capacitor 70 charged by the feedback coil 66 during the off period of the transistor 54 is due to the poor regulation characteristic of the inverter transformer composed of the primary coil 14 and the output coil 16. The smaller the load current taken out from the inverter circuit 11, the larger the load current, and this charging voltage is added to the base voltage in the direction of turning on the Zener diode 72 and applied. As a result, the Zener diode 72 is turned on at a base voltage lower than that during steady charging, the base current is shunted to shorten the on time of the transistor 54, and the device body 20 is unloaded or lightly loaded from the power source body 12. The power consumption of the inverter circuit 11 can be limited as much as possible.

A power signal of a frequency sufficiently higher than the commercial frequency generated by the inverter circuit 11 as described above is
The output coil 16 on the side of the apparatus body 20 electromagnetically coupled with the primary coil 14 reduces the voltage down to the charging voltage, and then the diode 78 selectively supplies a half-wave to the secondary battery 34 for charging.

The device main body 20 accommodates a plurality of secondary batteries 34 such as nicad batteries in an upper part of a hollow main body case 80 having a rectangular cross section, and a secondary battery in the lower part of the main body case 80. 34 is provided with a power feeding unit 82 that supplies a predetermined charging current. Further, on the lower end side of the main body case 80, the power supply main body 12
The receiving portion 84 into which the side contact surface 22 is fitted is provided, and the upper surface side is provided with a plug 86 for supplying power from the secondary battery 34 to an external load 83 such as a motor.

Inverter circuit 11 provided in the power supply body 12
The primary coil 14 is wound on a coil bobbin 88 that is provided in a central portion of the main body case 36 in a horizontal state with its central axis oriented in the longitudinal direction. Further, the center of the coil bobbin 88 is penetrated to extend the thin rod-shaped core 30 formed of a ferromagnetic material such as ferrite, and the both ends 90 of the core 30 are separated into both ends in the longitudinal direction of the contact surface 22. Have been arranged.

On the other hand, the output coil 16 on the device body 20 side
Also has substantially the same structure as the primary coil 14 on the power supply body 12 side, and extends both end faces 92 of the core 32 up to the contact face 24, and both end faces 90 of the core 30 on the primary coil 14 side. 90 and the arrangement position are matched.

Therefore, as shown in FIG. 3B, when the power source main body 12 and the device main body 20 are properly mounted with the contact surfaces 22 and 24 aligned, the power source main body 12 side and the device main body 20 are attached.
The cores 30 and 32 on the side are joined to each other through the end faces 90 and 92 thereof. As a result, the magnetic path 93 that goes around between the primary coil 14 and the output coil 16 is formed, and both coils 1
4 and 16 are appropriately electromagnetically inductively coupled, and a predetermined voltage is induced across the output coil 16 in response to a change in current in the primary coil 14. The induced voltage is applied to the inverter circuit 11
The voltage generated during the off period of the switching transistor 54 is selectively extracted by the rectifying diode 78,
It is sent to the secondary battery 34 and used for charging.

The present invention has the above-described structure, and is characterized by the structure of the contact surfaces 22 and 24 between the power supply main body 12 and the device main body 20.

That is, as shown in FIG. 3A, the power supply main body 12
Even if a foreign matter such as a clip is placed on the contact surface 22, the central portion of the contact surface 22 on the side is bulged upward in a gentle arc shape to form the protrusion 28. It is designed to slide easily.

Further, by increasing the distance between the primary coil 14 and the contact surface 22 as much as possible, the magnetic flux density of the magnetic field 94 by the primary coil 14 on the contact surface 22 is reduced, and even if the contact surface 22 is Even if a foreign object is placed on the
Together with the output limiting unit 60 of the inverter circuit 11, the heat generated in the foreign matter is suppressed to the minimum.

On the other hand, the shape of the contact surface 24 on the device body 20 side is curved so as to match the shape of the protrusion 28 provided on the contact surface 22 on the power supply body 12 side, and the body on the power supply body 12 side is curved. By providing the device main body 20 side with the receiving portion 84 that surrounds and fits the upper end portion of the case 36 from the peripheral surface 96, the device main body 20 is firmly attached to the power supply main body 12 side and prevented from sliding off from the power supply main body 12. is doing.

The shape of the protrusion 28 is not limited to the arcuate slope extending only in the longitudinal direction as described above, and the same inclination may be provided in the short side direction or the inclination may be linear. Is also possible. In short, even if a small piece of metal is placed on it, the mounting state is not stable, and if the structure is such that it slides down onto the floor immediately or with a slight vibration, its shape can be arbitrarily changed.

The range of sliding down is the core 30.
It may be determined by the magnetizing force exerted by the magnetic flux on the metal piece.
For example, in the above-described embodiment, it is also possible to make the peripheral edges of both ends 90 of the core 30 gently projecting, and make the middle part flat or recessed into a trapezoidal shape or a double camel shape. is there. Even if the metal piece slipped down into the recessed portion reaches a temperature (for example, 40 ° C. or less) that has a small effect on the human body or the like, it may be in a range in which there is no practical problem.

Further, the shapes and coupling states of the primary coil 14 and the output coil 16 can be changed as appropriate as long as electromagnetic induction coupling is possible. For example, the position or direction of the core 30 may be changed, or the oscillation frequency of the inverter circuit 11 may be increased to form the coil in a printed shape and eliminate the core itself.

Further, the inverter circuit 11 is not limited to the self-excited type as described above, and may be of the separately excited type additionally provided with an oscillator for turning on / off the switching transistor 54, and the configuration thereof is not particularly limited. Furthermore, as the primary side oscillation unit 10, instead of using the inverter circuit 11 as described above, the frequency of the commercial AC power source 40 may be used as it is.

FIG. 5 shows another embodiment of the present invention in which the protrusion 28 formed on the contact surface 22 on the power source body 12 side is a linear slope and the protrusion 28 is a pivot point. It is configured to be swingable in the vertical direction around 98. Further spring body 10
When the device main body 20 is detached as shown in FIG. 5 (a), the inclined position of the projecting portion 28 is maintained by urging it upward at 0. Also, the primary coil 1
The core 30 of No. 4 is oriented in the vertical direction, and the contact surface 22
While the tip of the hole 102 is provided on the
By making the output coil 16 air-core, when the device main body 20 shown in FIG. 5B is mounted, the core 30 is fitted in the center 104 of the output coil 16 and coupled to the primary coil 14.

On the other hand, the embodiment shown in FIG.
The side contact surface 22 is provided with a closing plate 106 for forcibly discharging the foreign matter on the contact surface 22 to the outside of the main body case 36. That is, the main body case 36 on the power supply main body 12 side
Inside, a mounting hole 108 into which the output coil 16 portion of the device body 20 is inserted together with the body case 80 is provided, and as shown in FIG. 6A, the opening 110 is biased in the closing direction by a spring body 112. It is closed by a closing plate 106. In this case, the closing plate 106 does not have to move to the same plane as the outer wall of the main body case 36, and it is sufficient if the metal piece or the like can be moved to a position that is not affected by the magnetizing force of the core 30.

FIG. 7 shows still another embodiment, in which the main body case 36 of the power source main body 12 is formed in a cylindrical shape with the upper and lower surfaces 114, 114 being flat. Further, the core 30 penetrating the primary coil 14 is formed into a linear shape so that the main body case 36 faces the horizontal direction.
Is disposed in the center of the
0 extends to the peripheral surface 116 of the main body case 36.
Therefore, the contact surface 22 on the power supply main body 12 side always faces the vertical direction, and even if the main body case 36 is laid sideways so that the contact surface 22 faces upward, the main body case 36 including the contact surface 22. A projecting portion 28 is formed on the entire peripheral surface 116, and the placement of foreign matter such as metal pieces is forcibly excluded.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a basic configuration of the present invention.

FIG. 2 is a partially cutaway perspective view showing an example in which the present invention is applied to a charging device.

FIG. 3 is an explanatory view showing a procedure for mounting the device main body on the power supply main body, in which (a) shows a detached state of the both and (b).
Indicates a combination state.

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

FIG. 5 is an explanatory view showing another embodiment of the present invention,
(A) shows the state where the device body is removed from the power supply body,
(B) shows the mounted state.

6A and 6B are explanatory views showing still another embodiment of the present invention, in which FIG. 6A shows a state in which the device body is removed from the power source body, and FIG.

7A and 7B are explanatory views showing still another embodiment of the present invention, in which FIG. 7A shows a state in which the device body is removed from the power source body, and FIG.

[Explanation of symbols]

 10 primary side oscillating section 11 inverter circuit 12 power supply body 14 primary coil 16 output coil 18 load 20 equipment body 22 contact surface on power supply body side 24 contact surface on equipment body side 26 removing means 28 projecting portion 30 core of primary coil 32 Output coil core 34 Secondary battery 36 Power supply main body case 40 Commercial AC power supply 58 Output control unit 60 Output limiting unit 80 Device main body case 90 Core end face 92 Core end face 93 Magnetic path 94 Magnetic field 106 Closing plate

Front page continuation (72) Inventor Mitsuo Yamanaka 4680 Ikata, Hachijo-machi, Tagawa-gun, Fukuoka Prefecture Kyushu Hitachi Maxell Co., Ltd. In Hitachi Maxell Co., Ltd. (72) Inventor Eiji Sakata 4680 Ikata, Hachijo-machi, Tagawa-gun, Fukuoka Prefecture Kyushu Hitachi Maxell Co., Ltd.

Claims (3)

[Claims] 1. A power supply body (12) having a primary side oscillating section (10) and a primary coil (1) of the primary side oscillating section (10).
4) and a device body (20) having a load (18) fed with power through an output coil (16) electromagnetically coupled to each other, are detachable from each other via contact surfaces (22) (24) thereof. A small electric device that can be mounted on the contact surface (22) on the power supply body (12) side, which is different from the device body (20) and can be removed from the contact surface (22). A small electric device comprising means (26) for 2. The removing means (26) is a projection (28) formed over substantially the entire contact surface (22) on the power source body (12) side. Item 1. A small electric device according to item 1. 3. The above-mentioned primary coil (14) and output coil (16) are individually provided with cores (30) (32), and end faces (90) (92) of both cores (30) (32) are connected to a power source. Contact surfaces (22) (2) of the main body (12) and the device main body (20)
4) The small electric device according to claim 2, wherein the small electric devices are arranged above each other.