JPH06319232A - Small-sized electrical equipment - Google Patents

Abstract

PURPOSE:To prevent a heat generation accident misconceiving a foreign matter disposed while being adjoined to a power supply body as an equipment body by mutually constituting the power supply body supplying power and the equipment body with load detachably. CONSTITUTION:A primary coil 14 is arranged at an internal position magnetically separated from a main body case 22 during a time when an equipment body 20 is detached from a power supply body 12. Consequently, magnetic flux density by a magnetic field 107 output from the primary coil 14 is maintained at a sufficiently small value at the peripheral position of the main body case 22 for example, no eddy current is generated even when a foreign matter such as a metallic piece is placed on the main body case 22. Accordingly, a heat generation accident misconceiving the foreign matter disposed while being adjoined to the power supply body 12 as the equipment body 20 can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various types of small electric equipment such as a charging device, an electric toothbrush or an electric tool, and in particular, a power supply body for supplying electric power and an equipment body equipped with a load can be attached to and detached 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 main body side, and the device main body is always set on the power supply main body side to maintain the state of charge 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 oscillating part such as the inverter circuit provided in the power supply main body is always in the driving state, the load main body is exclusively used for the purpose of power saving when the main body is removed from the power supply main body for a long time. The output of the primary side oscillating unit is also controlled according to the presence or absence.

[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 inventors of the present invention have found that the primary side oscillating portion is always kept in a driving state while the primary coil is magnetically separated from the peripheral surface of the main body case in the power supply main body. By storing in the state, the magnetic flux density on the peripheral surface of the main body case is kept as small as possible, and the magnetic resistance of the magnetic path passing through the output coil is reduced in conjunction with setting the device main body to the power supply main body. By doing so, they have found that the above-mentioned inconveniences are resolved at once.

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 power supply main body 12 having a primary side oscillating portion 10 such as an inverter circuit, as shown in FIG. And a device body 20 having a load 18 fed through an output coil 16 electromagnetically coupled to the primary coil 14 of the primary side oscillating section 10 can be detachably coupled to each other.

Further, the primary coil 14 on the side of the power supply body 12 is arranged at a position magnetically separated from the outer peripheral surface of the body case 22 when the device body 20 is detached from the power supply body 12, while the device for the power supply body 12 is arranged. It is characterized in that it is provided with means 24 for making the output coil 16 and the primary coil 14 magnetically close to each other in association with the mounting of the main body 20.

[0008]

With the above structure, the primary coil 14 is disposed at an internal position magnetically separated from the main body case 22 while the main body 20 is separated from the power supply main body 12. Therefore, in the peripheral position of the main body case 22, the magnetic flux density due to the magnetic field 107 output from the primary coil 14 is kept sufficiently small, and even if a foreign matter such as a metal piece is placed on the main body case 22, eddy current is not generated. Few.

On the other hand, when the device main body 20 is correctly set in the power supply main body 12, the approaching means 24 of the primary coil 14 and the output coil 16 works in synchronism with it, and both the coils 14 and 16 are connected.
The two are magnetically coupled to each other, and a predetermined electric power is supplied from the power supply body 12 side to the load 18 in the device body 20.

[0010]

As described above, the present invention is configured to suppress the magnetic field 107 leaking to the outside of the main body case 22 as much as possible when the device main body 20 is detached from the power main body 12, so that the power main body 12 is prevented. It is possible to prevent a heat generation accident in which a foreign substance placed close to is mistakenly recognized as the device body 20.

[0011]

EXAMPLES The following is an example in which the present invention is applied to a rechargeable battery charging device, but the present invention is not limited to this, and is also applicable to various small electric devices such as electric toothbrushes, electric tools, and power packs used therefor. Of course, the same can be done.

A charging device for carrying out the present invention is shown in FIGS.
As shown in its overall configuration, the inverter type power source main body 12 and the lower end thereof is detachably fitted to the power source main body 12, and the charging current sent from the power source main body 12 using electromagnetic induction coupling is supplied. It is composed of a device body 20 that can be used to charge the internal secondary battery 26.

The electric circuit which constitutes the charging device has a commercial AC power source 30 input through a power plug 28 extending from the main body case 22 of the power source main body 12 to the outside, as specifically shown in FIG. It is connected to the inverter circuit 34 via the protection circuit 32.

The protection circuit 32 blocks the input of a large current by the metal film resistor 36 connected in series with the power supply line to the inverter circuit 34, while preventing the input of the surge voltage by the overvoltage absorbing element 38 connected in parallel. To do.
Further, after the input voltage is rectified by the rectifier 40, the operation of the inverter circuit 34 at the time of overheating can be forcibly stopped by the temperature fuse 42, and the outflow of noise from the inverter circuit 34 side is prevented by the capacitor 44. There is.

The inverter circuit 34 includes the primary coil 14 on the collector side of the switching transistor 46, the protective resistor 48 on the emitter side, and an output control section 50 and an output limiting section 52 on the base side. ing.

The output control unit 50 comprises a resistor 54, a capacitor 56 and a feedback coil 58 connected in series, and the on / off cycle of the switching transistor 46 is set to, for example, about 40 kHz depending on the charging / discharging time constants of the resistor 54 and the capacitor 56. While regulating, the feedback coil 58 and the capacitor 56 are used to switch the switching transistor 46.
The on-time of is regulated.

That is, the capacitor 5 is connected via the resistor 54.
When 6 is charged and the base voltage of the switching transistor 46 exceeds the set value, the collector current starts flowing in the primary coil 14, and the increase in the collector current generates a voltage in the direction to turn on the transistor 46 in the feedback coil 58. Then, the transistor 46 is rapidly turned on.
After the transistor 46 is turned on, charging and discharging of the capacitor 56 progresses, and the base current decreases, so that the direction of the voltage output from the feedback coil 58 is reversed, and a reverse bias is applied between the base and emitter of the transistor 46 to cause the transistor 46. Turn off rapidly. Transistor 4 mentioned above
By repeating the on / off operation of No. 6, the inverter circuit 34 performs self-excited oscillation at a predetermined frequency.

The capacitor 60 connected in parallel with the primary coil 14 absorbs the shock voltage generated when the transistor 46 is turned off. Also transistor 4
The protection resistor 48 provided on the emitter side of 6 controls the off time of the transistor 46 by increasing the emitter potential of the transistor 46 in response to the increase of the collector current, and an excessive current flows into the transistor 46. It is to prevent it.

The output limiting section 52 includes the feedback coil 5 described above.
The capacitor 62 is connected in parallel with the capacitor 8 and the zener diode 64 is connected in series with the capacitor 62. Here, the feedback coil 58 and the capacitor 62
A diode 66, which enables charging only during the off period of the switching transistor 46, is interposed between the two, and between the Zener diode 64 and the capacitor 62,
During the ON period of the transistor 46, the diode 68 is turned on by the base voltage to allow the capacitor 62 to be discharged.
Are installed respectively.

Therefore, the charging voltage of the capacitor 62 charged by the feedback coil 58 during the off period of the transistor 46 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 extracted from the inverter circuit 34, the larger the load current, and this charging voltage is added to the base voltage in the direction of turning on the Zener diode 64 and applied. As a result, the Zener diode 64 is turned on at a lower base voltage than during steady charging, the base current is shunted to shorten the on time of the transistor 46, and the device body 20 is unloaded or lightly loaded from the power source body 12. The power consumption of the inverter circuit 34 can be limited as much as possible.

The power signal of a frequency sufficiently higher than the commercial frequency generated by the inverter circuit 34 as described above is
After the voltage is reduced to the charging voltage by the output coil 16 on the device main body 20 side that is electromagnetically coupled with the primary coil 14, the diode 70 selectively supplies a half-wave to the secondary battery 26 for charging.

The present invention is characterized by the coupling mechanism of the primary coil 14 and the output coil 16 described above, particularly in the structure of the power supply body 12 side.

That is, as shown concretely in FIGS. 2 and 3, a hollow main body case 22 having an upper opening.
Is closed by an abutment surface 74, and the receiving portion 73 is provided with an opening 72 at the upper end.
And a closed storage chamber 75 are sectioned and formed, and the electric circuit on the power supply main body 12 side is stored inside the storage chamber 75.

The primary coil 14 provided inside the storage chamber 75
Is wound around a coil bobbin 76, and a core 78 formed of a ferromagnetic material having a high magnetic permeability such as ferrite is provided at the center of the coil bobbin 76 so as to project upward from the coil bobbin 76 by a predetermined length.

On the other hand, a cylindrical engagement protrusion 80 having a diameter slightly larger than the diameter of the core 78 is provided from the substantial center of the contact surface 74 upward, and the upper end portion of the core 78 is provided in the engagement protrusion 80. Engagement holes 82 that fit from the lower surface side are formed.

The coil bobbin 76 has sliding pieces 84 extending in the left-right direction from the flange portions 83, 83 provided on the upper and lower sides thereof. Further, on the inner surface 85 of the main body case 22, two sliding rails 8 are provided with a space slightly wider than the width of the coil bobbin 76.
By fixing 6 and 86 in the vertical direction and fitting the sliding piece 84 of the coil bobbin 76 into the sliding rail 86, the primary coil 14 becomes integral with the coil bobbin 76 and the core 78, and the following moving mechanism 88 is provided. Thus, the core 78 is swung vertically, and the core 78 is inserted into and removed from the engagement hole 82.

The moving mechanism 88 for the primary coil 14 allows the upper end 91 of the thin plate-shaped operation piece 90 to be retracted and retracted from a hole 92 provided in the contact surface 74, and between the lower portion 93 and the lower surface 95 of the main body case 22. By providing the spring body 94 in the above, the operation piece 90 is biased upward. Further, the lower portion 93 of the operation piece 90 and the lower end 98 of the core 78 are pivotally supported to each other via the arm 100 having a spring property, and the intermediate portion thereof is supported by the support portion 102 provided on the inner surface 85 of the main body case 22. It is pivotally supported.

That is, the arm 100 is entirely formed of a thin plate-like rod, and a through hole 1 is provided in a part of the arm 100 in the longitudinal direction so that at least a part thereof is flexibly deformed. There is. Further, engaging rods 2 and 3 are projectingly formed at both ends thereof in parallel with the supporting direction of the supporting portion 102, while the lower end 98 of the core 78 and the lower portion 93 of the operating piece 90 are respectively engaged with each other as described above. The rods 2 and 3 are fitted to form elongated holes 4 and 5 that can slide in the left and right directions.

The main body case 104 on the equipment main body 20 side has a hollow shape whose cross-sectional shape is substantially the same as that of the opening 72 of the main body case 22 on the power supply main body 12 side, and the power source is provided on the contact surface 106 on the lower surface side. An engaging hole 108 into which the engaging projection 80 provided on the abutting surface 74 of the main body 12 is fitted is provided, and the bobbin 110 of the output coil 16 is provided inside the main body case 104 so as to be centered with the engaging hole 108. The plug 114 is fixed and extends from the top surface so that the secondary battery 26 can be supplied with power from an external load 112 such as a motor.

Therefore, as shown in FIG.
When the lower end of the device body 20 is fitted into the upper opening 72 of the device and pushed in, the contact surface 106 on the device body 20 side pushes and lowers the upper end 91 of the operation piece 90, and the lowering is performed by the arm 100 with respect to the primary coil 14. As a result of being transmitted as an upward shifting force, the upper end portion of the core 78 fits into the engagement hole 82. At the same time, the engagement protrusion 80 is fitted into the engagement hole 108 on the device body 20 side, and the primary coil 14 and the output coil 16 are
And are magnetically coupled to each other.

At that time, the engaging rods 2 and 3 provided at both ends of the arm 100 respectively move through the long holes 4 and 5 to adjust the length between the pivot points 98, 102 and 93, and at the same time, the arms themselves. The core 78 is slightly curved due to its springiness, and biases the core 78 upward.

The moving mechanism 88 is not limited to the seesaw type mechanical mechanism as described above, but can move the primary coil 14 in the up and down direction such as shifting to the electromagnetic type in conjunction with the ON operation of the switch contact. In that case, it goes without saying that it can be implemented by appropriately changing it.

In the above embodiment, the core 78
Is provided only on the primary coil 14 side, and the core 78 on the primary coil 14 side penetrates the output coil 16 when the power supply main body 12 and the device main body 20 are coupled, but the configuration is not limited to this, and the same applies to the output coil 16 side. It may be provided with a core. By increasing the oscillation frequency of the inverter circuit 34, the core itself can be eliminated, and the coil can be printed, and in any case, the contact surfaces 74 and 106 can be formed in a flat shape.

Further, instead of moving the primary coil 14 together with its core 78 as described above, the primary coil 14
It is also possible to transfer the fixed circuit board together.

Further, the device body 20 with respect to the power source body 12
By making it possible to change the insertion depth of the power coil and changing the approach distance between the primary coil 14 and the output coil 16 in a stepwise manner, the power that can be supplied from the power supply main body 12 side to the device main body 20 side, that is, the secondary battery The charging current supplied to 26 can be changed stepwise.

Further, the configuration of the inverter circuit 34 is not limited to the self-excited type, but may be appropriately changed and implemented by, for example, a separately excited type having a switching oscillator separately provided. Further, as the primary side oscillation unit 10, instead of using the inverter circuit 34 as described above, the frequency of the commercial AC power source 30 may be used as it is.

6 to 11 show another embodiment of the present invention, showing a state where the power source main body 12 and the device main body 20 are separated from each other in (a) and a state where they are connected to each other in (b). .

In the embodiment of FIG. 6, the primary coil 14
Is fixed in the main body case 22, and only the core 78 is vertically moved. It is convenient to maintain the core 78 removed from the primary coil 14 as in this example, because the magnetic field 107 itself around the primary coil 14 becomes weak.

Further, as shown in FIG. 7, the core 78 may be provided so as to project from the apparatus main body 20 side, and the core 78 may be inserted into the primary coil 14 in an air-core state to couple the output coil 16 to the primary coil 14. In this example, only the central portion of the primary coil 14 is configured to be opened and closed in the vertical direction by the closing body 118 urged by the spring body 116. However, the peripheral portion of the primary coil 14 of the device body 20 is closed. It may be closed by a magnetic shield plate that opens in the horizontal direction in conjunction with mounting on the power supply body 12 side.

Further, as shown in FIG. 8, the primary coil 14 is fixed at a position separated from the contact surface 74 in the main body case 22 of the power supply main body 12, and the gap 120 between the primary coil 14 and the main body case 22 is provided. On the other hand, the output coil 16 may be inserted together with the main body case 22 from the lateral direction of the main body case 22.

In the embodiment of FIG. 9, the primary coil 14
The output coil 16 and the output coil 16 both include the cores 78, 78a, and the primary coil 14 is arranged at a position slightly recessed from the contact surface 74, so that the device main body 20 can be moved.
The magnetic field 107 output from the primary coil 14 is prevented from leaking to the outside of the main body case 22 when separated from 2.

When power is supplied, the moving mechanism 88 of the core 78 shown in the embodiment of FIG. 2 is moved in parallel in the connecting direction, whereas in this embodiment it is constructed so as to be moved in the direction orthogonal to the connecting direction. And the contact surface 10 of the device body 20
The auxiliary core 122 is interposed between the primary coil 14 and the back surface of the contact surface 74 in conjunction with making the contact surface 6 of the power supply body 12 side coincide with each other. As a result of 78.78a approaching each other, both coils 14.16 are magnetically coupled to each other.

In the embodiment of FIG. 10, the primary coil 14 is rotatable about its eccentric position 124, and when the device body 20 is separated from the power source body 12, the core 78 thereof is abutted. It is arranged in parallel with the surface 74. Therefore, the primary coil 14 is always in contact with the contact surface 7
4, the generated magnetic field 107 is maintained without leaking to the outside of the main body case 22, but the primary coil 14 returns to the normal position in conjunction with the installation of the main body 20 of the device, and the primary coil 14 is moved to the main body 20 side. It is possible to supply a predetermined power.

Further, in the embodiment shown in FIG. 11, the primary coil 14 is separated from the contact surface 74 toward the inside of the main body case 22 and the central axis is positioned parallel to the contact surface 74. The core 78 that is fixed inside and penetrates the primary coil 14 is extended to a position sufficiently separated on the contact surface 74. Therefore, both ends 1 of the core 78 are always
The magnetic resistance between 26 and 126 is large, and the magnetic field 107 leaking from the primary coil 14 is concentrated and generated around the primary coil 14 in the main body case 22.

However, the output coil 16 on the device body 20 side
By making the configuration of the core 78a and the configuration of the core 78a substantially the same as the configuration on the power supply main body 12 side, the device main body 20 and the power supply main body 12 are
When the contact surfaces 74 and 106 are aligned with each other, the primary coil 14
Magnetic path 1 with low magnetic resistance returning from the output coil 16 through the output coil 16
28, the magnetic field generated on the side of the primary coil 14 effectively links with the output coil 16.

[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 a central vertical cross-sectional view of the charging device of FIG. 2, showing a state where the device body is removed from the power supply body.

FIG. 4 is a central longitudinal cross-sectional view of the charging device of FIG. 2, showing a state where the device body is attached to the power supply body.

FIG. 5 is a circuit diagram showing an electrical configuration of the charging device.

FIG. 6 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 respective combined states.

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. 7B shows a combined state.

8A and 8B are explanatory views showing still another embodiment of the present invention, wherein FIG. 8A shows a state in which the device body is removed from the power source body, and FIG. 8B shows a combined state.

9A and 9B are explanatory views showing still another embodiment of the present invention, wherein FIG. 9A shows a state in which the device body is removed from the power source body, and FIG. 9B shows a combined state.

10A and 10B are explanatory views showing still another embodiment of the present invention, in which FIG. 10A shows a state in which the device body is removed from the power source body, and FIG. 10B shows a combined state.

11A and 11B are explanatory views showing still another embodiment of the present invention, in which FIG. 11A shows a state in which the device body is removed from the power source body, and FIG. 11B shows a combined state.

[Explanation of symbols]

 10 primary side oscillating section 12 power supply main body 14 primary coil 16 output coil 18 load 20 equipment main body 22 main body case on the power supply main body side 24 approach means between primary coil and output coil 26 secondary battery 30 commercial AC power supply 34 inverter circuit 50 output control section 52 Output Limiting Part 74 Contact Surface on Power Supply Main Body 78 Core 88 Moving Mechanism 104 Main Body Case on Equipment Main Body 106 Contact Surface on Equipment Main Body 107 Magnetic Field

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[Procedure amendment]

[Submission date] October 22, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 11

[Correction method] Added

[Correction content]

FIG. 11

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 (2)

[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).
A small electric device in which the device (4) and a device body (20) having a load (18) supplied with power via an output coil (16) electromagnetically coupled to each other can be detachably connected to each other. The primary coil (14) on the side of the power supply body (12)
When the device body (20) is detached from the power supply body (12), the device body (20) is arranged so as to be magnetically separated from the outer peripheral surface of the body case (22), and the device body (20) is attached to the power supply body (12). A small electric device comprising a means (24) for interlockingly making the output coil (16) and the primary coil (14) magnetically close to each other. 2. The approaching means (24) for connecting the primary coil (14) and the output coil (16) to each other with the primary coil (14) provided in the main body case (22) against the contact surface (74). The small electric device according to claim 1, which is a moving mechanism (88) capable of approaching and separating.