JP2523593B2 - Electric vacuum cleaner - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric vacuum cleaner, and more particularly to a bidirectional semiconductor element for controlling the electric power of an electric blower, a trigger circuit for determining ON / OFF thereof, and cooling for suppressing heat generation. Regarding those having fins.

[Conventional technology]

Conventionally, there has been a vacuum cleaner that controls the electric power of an electric blower in order to change the suction force according to the cleaning location.

From the viewpoint of handleability, it is general that a variable resistor, which is a part of a trigger circuit wired through a hose core wire, is provided near the hose, and the electric power of the electric blower is changed by changing the resistance.

However, sand dust collides with the hose and the inner wall of the extension tube at the hose end, and a large amount of static electricity of up to about 30 kv is generated due to friction.This static electricity transfers to the hose core wire, malfunction of the trigger circuit, damage of the trigger element. There was a risk of causing such problems.

Therefore, as described in JP-A-61-209627, a part of the trigger circuit is connected to the electrically insulated metallic housing of the electric blower, and the generated static electricity is transferred from the metallic housing to the coil of the electric motor. A technique has been proposed in which the above-mentioned danger is prevented by discharging.

[Problems to be solved by the invention]

However, in the technique described in JP-A-61-209627, it is necessary to electrically connect the printed circuit board on which the trigger circuit is mounted to the housing of the electric blower with a lead wire or the like. Therefore, there is a problem that the assemblability is poor and the structure of the vacuum cleaner is restricted.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate these drawbacks of the prior art, and to provide an electric vacuum cleaner having excellent protection against static electricity, simple wiring, and excellent assembling.

[Means for solving problems]

In order to achieve the above object, a feature of the present invention is that a bidirectional semiconductor element for controlling the electric power of an electric blower is closely attached to the bidirectional semiconductor element in order to suppress heat generation, and the electrically conductive portion and the electrical part are electrically connected. A trigger circuit for setting the ON and OFF times of the bidirectional semiconductor element, the trigger circuit being connected to the gate electrode of the bidirectional semiconductor element, An electric vacuum cleaner capable of setting and controlling the electric power of an electric blower by mounting the bidirectional semiconductor element, the cooling fin, and the trigger circuit on the same printed circuit board,
The trigger circuit is electrically connected to the cooling fin, and a power supply transformer for exchanging a voltage applied to the trigger circuit is arranged near the cooling fin.

[Action]

According to the present invention, static electricity generated at the hand of the hose is moved from the trigger circuit to the cooling fin to collect the current, and the static electricity collected is discharged from the cooling fin to the power transformer having the high-power section, thereby causing malfunction or malfunction. It is possible to prevent destruction of the trigger element.

Further, since the cooling fin and the trigger circuit are mounted on the same printed circuit board, the connection is easy and the wiring and the assemblability can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. Second
In the figure, reference numeral 1 is a plastic main body case, an electric blower 2 is fixed to the rear, and a dust collecting portion 4 for collecting dust sucked from a suction port 3 is detachably provided on the front. . Reference numeral 5 is a wheel, 6 is a caster, 7 is a handle, and a trigger circuit 9, a bidirectional semiconductor element 10 and a cooling fin 11 are mounted and arranged on the same printed circuit board 12 near the exhaust port 8.

Next, the operation will be described. In FIG. 3, 13 is a suction port, 14 is an extension pipe, 15 is a hose, and 16 is a cleaner body, and dust sucked from the suction port 13 passes through the extension pipe 14 and the hose 15 and then from the suction port 3 to the cleaner body 16. Then, the dust is collected in the dust collecting portion 4, and only clean air passes through the electric blower 2 and is discharged from the discharge port 8.

FIG. 4 is a circuit diagram of the vacuum cleaner according to the present invention, which has a bidirectional semiconductor element 10 for controlling the electric power of the electric blower 2 by AC phase control, and 17 to the gate terminal G of the bidirectional semiconductor element 10. That regulates the polarity of the output signal of the device, 18 is a pulse transformer for sending the trigger pulse output from the trigger device 19 directly between G-T ₁ of the bidirectional semiconductor device, and 20 and 21 are the trigger devices. 5 Time t ₁ for outputting a trigger pulse as shown in FIG. 5A, that is, a bidirectional semiconductor element
A charge / discharge circuit is formed with a variable resistor and a capacitor that determines the time from 10 to ON. Variable resistance
Reference numeral 21 is located at the proximal portion 15a of the hose 15 in FIG. 3, and is connected to the trigger circuit through the hose core wire. Variable resistance
The 21 also doubles as a switch mechanism, and can be turned on and off by changing the resistance manually. 22 and 23 are resistors for voltage division, 24 is a constant voltage diode, 25 and 26 are resistors for limiting current, 27 is a full-wave rectifier circuit, and 28 is a power transformer for converting the trigger circuit 9 into a low voltage. Reference numeral 29 is a high resistance that electrically prevents the cooling fin 11 from causing a dielectric breakdown and causing the cooling fin 11 to have the same potential as the high voltage on the power supply side, so that the trigger circuit 9 is not affected. The time constant for the trigger element 17 to output the pulse signal is determined by the time constant determined by the variable resistor 21 and the capacitor 20, and the trigger pulse is applied between G-T ₁ of the bidirectional semiconductor element 10 through the pulse transformer 18, and the bidirectional The semiconductor element 10 is turned from OFF to ON, and the same thing is repeated in the next half cycle. Therefore, the electric blower terminal voltage waveform as shown in (b) is obtained in response to the trigger pulse shown in FIG. 5 (a).
When the resistance value of the variable resistor 21 is increased, the time constant is also increased, the trigger pulse output time t ₁ is also increased, and the ratio of missing from the sine wave of the terminal voltage of the electric blower is increased, and the power is decreased. On the contrary, if the resistance value of the variable resistor 21 is decreased, the power increases. As described above, the suction force can be controlled by changing the electric power by manually operating the variable resistor 21 of the hose proximal portion 15a.

FIG. 6 shows a printed circuit board 12 on which a trigger circuit 9, a bidirectional semiconductor element 10 and a metal cooling fin 11 which is tightly screwed and fixed to the trigger circuit 9 are collectively mounted, as shown in FIG. The cooling fin 11 whose one end is electrically insulated from the conductive portion of the bidirectional semiconductor element 10 is electrically connected to the cooling fin through the solder copper pattern 12a as shown in FIG. In addition, 31 and 32 are connectors for one-touch connection with the electric blower, the power supply, and the hose core wire and the lead wire.

With the above configuration, when dust such as sand dust is inhaled, static electricity of up to 30 kV is generated due to friction with the inner wall of the hose 15 and the extension tube 14, and even if static electricity is transferred to the hose core wire, static electricity is transferred to this cooling fin 11. Cooling fins that collect current and are shown in Fig. 6
Since the static electricity is discharged to the power transformer 28 having a strong electric portion arranged near 11, it is possible to prevent malfunction and destruction of the trigger element 19. In addition, since the cooling fin and the trigger element can be electrically connected on the printed circuit board, the wiring on the assembly wiring can be improved as compared with the conventional one in which a long lead wire is extended from the printed circuit board and connected to the housing of the electric blower. It has advantages such as no effort and no restriction on the structure of the vacuum cleaner.

In FIG. 7, the lead wire 30 extending from one end of the trigger element in another embodiment is electrically connected by being sandwiched between the cooling fin 11 and the printed circuit board 12. The lead wire 30 is also short on the wiring. The same effect can be obtained because there is little trouble.

〔The invention's effect〕

According to the present invention described above, static electricity generated at the hand of the hose is moved from the trigger circuit to the cooling fin to collect the electricity, and the collected static electricity is discharged from the cooling fin to the power transformer having the high-power section. It is possible to prevent malfunction and destruction of the trigger element.

Further, since the cooling fin and the trigger circuit are mounted on the same printed circuit board, the connection is easy and the wiring and the assemblability can be improved.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part of a mounting portion of a cooling fin and a printed circuit board, FIG. 2 is a vertical sectional view of a cleaner body, FIG. 3 is a configuration diagram of an entire cleaner, and FIG. 4 is one embodiment of the present invention. FIG. 5 is a circuit diagram of a vacuum cleaner according to an example, FIG. 5 is a voltage waveform of each part, FIG. 6 is a component mounting view of a printed circuit board, and FIG. 7 is an enlarged view of a cooling fin and a mounting part of a printed circuit board according to another embodiment. 2 ... Electric blower, 9 ... Trigger circuit, 10 ... Bidirectional semiconductor element, 11 ... Cooling fin, 12 ... Printed circuit board,
19 …… Trigger element.

Claims (1)

(57) [Claims] 1. A bidirectional semiconductor element for controlling the electric power of an electric blower, a cooling fin closely attached to the bidirectional semiconductor element to suppress heat generation thereof, and electrically insulated from a conductive portion, and the bidirectionality. A trigger circuit for setting ON and OFF times of a semiconductor element, and connecting the trigger circuit to a gate electrode of the bidirectional semiconductor element so that the trigger circuit can set and control electric power of an electric blower. The electric vacuum cleaner according to claim 1, wherein the bidirectional semiconductor element, the cooling fin, and the trigger circuit are mounted on the same printed circuit board, and the trigger circuit is electrically connected to the cooling fin. A vacuum cleaner characterized in that a power transformer for exchanging a voltage applied to the trigger circuit is disposed near the fin.