JPH0353877B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an electric blower input control circuit in a vacuum cleaner.

Technical Background of the Invention Fig. 1 shows the external appearance of a conventional vacuum cleaner, in which there is a removable dust collection case 2 at the front of the main body case 1, and a hose insertion port 3 of the dust collection case 2 is connected to the main body case 1. Hose 4 is inserted. An operation switch section 6 is provided at the hose proximal section 5.

FIG. 2 shows the circuit configuration. Basically, an electric blower 8 and a bidirectional thyristor 9 are connected in series to a 100V AC power source 7 of AC 50/60Hz. A protective resistor R ₁ and a capacitor C ₁ are connected in parallel to this bidirectional thyristor 9 .
Further, on the gate side of the bidirectional thyristor 9, a gate trigger circuit 11 mainly consisting of a characteristic variable negative resistance element PUT10 and a capacitor _C2 is provided.
This PUT10 has a resistor R ₆ connected to the gate side,
It is characterized by R ₇ and turns ON when a voltage determined by these resistors R ₆ and R ₇ is applied to the anode side.
It is something to do. Therefore, the AC power supply 7 is connected to both ends of the resistors R ₆ and R ₇ via the diode D ₃ through the resistor R ₁₀ .
~Full wave rectification with rectifier circuit 12 by D ₆ , resistor R ₉
A constant voltage is applied via the Zener diode ZD. On the other hand, PUT10
A capacitor C ₂ is connected to the anode of .
Further, the cathode side of PUT 10 is connected to the gate of thyristor 13 via resistors R ₄ and R ₅ . This thyristor 13 is connected to the rectifier circuit 1 along with the resistor _R3.
Connected to 2. And thyristor 13,
Diodes D ₁ and D ₂ are connected in parallel to resistor R ₃ ,
Its midpoint is connected to the gate of the bidirectional thyristor 9, and a resistor R ₂ is connected between it and the anode.
is mediated.

Thus, the AC power source 7 is full-wave rectified by the rectifier circuit 12, and the voltage regulated by the Zener diode ZD charges the capacitor _C2 via the variable resistor _VR1 of the operation switch section 6. Therefore, when the charging voltage of this capacitor C ₂ reaches the voltage value determined by the resistors R ₆ and R ₇ , the PUT 10 is turned on. Therefore, if the variable resistor VR ₁ is variably operated, the charging cycle of the capacitor C ₂ changes according to the change in resistance, and the ON timing of the PUT 10 also changes. In any case, when PUT 10 turns on, the gate of thyristor 13 is triggered and turns on.
As a result, the anode of the thyristor 13 receives not only the rectified output from the rectifier circuit 12, but also the electric blower 8, the gate of the bidirectional thyristor 9, and the diode.
The current continues to flow through D ₁ , resistor R ₃ , thyristor 13 and diode D ₄ . This current continues to flow until the bidirectional thyristor 9 turns on and the voltage across its terminals drops, so even if the load is an inductive load such as the electric blower 8, the bidirectional thyristor 9
will definitely be triggered. Moreover, even after bidirectional thyristor 9 is turned on, thyristor 1
3 maintains the ON state with the current flowing through the rectifier circuit 12, so even if the bidirectional thyristor 9 is turned off due to vibration of the main current, it is turned on again. Even when the polarity of the AC power supply 7 is reversed, current similarly flows through the diode D ₃ , the thyristor 13 and the diode D ₂ .
Bidirectional thyristor 9 is turned on reliably.

In this way, the bidirectional thyristor 9 is controlled in accordance with the resistance change caused by the variable operation of the variable resistor VR ₁ , and the input to the electric blower 8 is controlled, and the electric blower 8 is turned off even at a low power factor. Never.

Problems with the Background Art In the conventional system, a high resistance resistor R ₁₁ is used to stop the electric shock in contrast to the variable resistor VR ₁ of the operation switch section 6.
R ₁₂ is interposed. For this reason, the variable resistor VR ₁
must also have high resistance (high impedance). The maximum and lowest resistance value of this variable resistor VR ₁ regulates the minimum input. In addition, in Figure 2,
SW indicates the OFF position of variable resistor VR ₁ ,
As a result, the electric blower 8 is stopped. However, variable resistors have variations due to mass production, and the deviations are about 10 to 15 times that of fixed resistors. For example, with a fixed resistor, a value of about ±2% can be easily obtained, but with a variable resistor, if the total resistance value exceeds 500KΩ, a deviation of about ±20 to 30% occurs. For this reason, even if the maximum resistance value of the variable resistor is set to 700KΩ for the minimum input setting, it will range from 490 to 910KΩ due to variations, and 800 to 910KΩ.
If it becomes about 900KΩ, the electric blower 8 may stop even if it is not in the OFF position, and the minimum input cannot be set.

Therefore, there is a method of selectively using variable resistors to manage the total resistance value, but this method is expensive.

Purpose of the Invention The present invention has been made in view of the above points, and it is possible to stably and reliably set the minimum input setting while using a variable resistor that causes variations in mass production. The purpose of the present invention is to obtain an electric blower input control circuit that can also alleviate variations in the electric blower.

SUMMARY OF THE INVENTION The present invention provides a variable resistor in the operating switch section to enable variable control of the input of the electric blower, and further provides a separate minimum input setting resistor to set the minimum input. By setting this, it is possible to stably set the minimum input without being affected by variations in the resistance value of the variable resistor.In addition, by providing a fixed resistor for correction in parallel with the variable resistor, the value of the variable resistor can be adjusted. It is constructed so that variations can be reduced.

Embodiment of the Invention A first embodiment of the invention will be described based on FIG. Components that are the same as those shown in FIGS. 1 and 2 are designated by the same reference numerals, and description thereof will be omitted. In this example,
The operation switch unit 6 is provided with a variable resistor VR ₁ and a fixed resistor R ₁₃ as a minimum input setting resistance. Here, the A region is a variable resistance region where the slider 14 is in contact with the common conductive pattern PC and the resistance pattern PR of the variable resistor VR ₁ , and the resistance pattern
The resistance value of PR increases from the left side to the right side in the figure, and reaches the maximum resistance value on the right side. An electrodynamic pattern PD connected to a fixed resistor _R13 is provided on the right side exceeding the maximum resistance value of the resistance pattern PR. Therefore, the slider 14 contacts the common conductive pattern PC and the conductive pattern PD B.
The fixed resistor _R13 is connected in the region, and the B region corresponds to the lowest input setting position. or,
In region C, the slider 14 contacts only the common conductive pattern PC, and corresponds to the OFF position.
In this way, the slider 14 has a common conductive pattern.
It moves the length of the PC.

In such a configuration, when the electric blower 8 is set to the lowest input, the slider 14 is positioned in the B region. As a result, a fixed resistor R ₁₃ is placed in series with the capacitor C ₂ regardless of the variable resistor VR ₁ , and based on the resistance value of this fixed resistor R ₁₃ , the bidirectional thyristor 9 and therefore the electric blower 8 are It will be controlled by the input. On the other hand, when the input is set to be higher than the minimum input, the resistance of the variable resistor VR ₁ is appropriately changed by slidingly displacing the slider 14 within the A region, and the input of the electric blower 8 is controlled according to this resistance change. It turns out. When stopping, the slider is positioned in area C.

Input control is performed in this way, but the minimum input setting is done by the fixed resistor _R13 , and the fixed resistor has a variation width of 1/10 or less of the maximum resistance value of the variable resistor, for example ±2 with a carbon film. %, metal film type with a tolerance of about ±0.2 can be easily mass-produced, making it possible to keep the minimum input variation extremely small and stable. Therefore, there is no possibility that the electric blower 8 will stop at the lowest input setting position, and there is no need to select the variable resistor VR ₁ , thereby reducing costs.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, the minimum input setting resistance is configured by a fixed resistance _R13 and a semi-fixed resistance _VR2 . According to this embodiment, by varying and fixing the semi-fixed resistor VR ₂ as necessary, the minimum input can be variably adjusted and the range of use can be expanded. For example, when cleaning purposes are limited, the minimum input can be set high (or low). In this embodiment, only the semi-fixed resistor VR ₂ may be used, but the presence of the fixed resistor R ₁₃ can suppress variations due to stoppage, etc.

Next, a third embodiment of the present invention will be explained with reference to FIG. In this embodiment, in addition to the fixed resistor R ₁₃ , a correction fixed resistor R ₁₄ is provided, and this fixed resistor R ₁₄ is a conductive pattern with a length corresponding to the A area.
Connected to PD ₂ . Therefore, fixed resistance _R14 becomes variable resistance when slider 14 is in area A.
This is connected in parallel with the VR ₁ variable resistor. Here, the fixed resistor R ₁₄ has a resistance lower than the maximum resistance value of the variable resistor VR ₁ and has a small tolerance, and is used to compensate for variations in the variable resistor VR ₁ , especially variations in the maximum resistance value. It is for the purpose of For example, variable resistor VR ₁ has a tolerance range of ±30%, fixed resistor R ₁₄ has a tolerance width of ±2%, and
If the resistance value is set to ⅓ of the maximum resistance value of the variable resistor VR ₁ , the variation can be reduced to around ±10%. More specifically, for example, assuming that the maximum resistance value of variable resistor VR ₁ is 2 MΩ and fixed resistor R ₁₄ = 700 KΩ, the variation in variable resistor VR ₁ is 1.4 to 2.6 MΩ.
, and the variation of fixed resistance _R14 is 686 to 714KΩ
It is. As a result, the combined resistance of both is approximately the ideal value.
The variation is about 470 to 560KΩ for 518KΩ, and the variation can be suppressed to ±10% or less.
As a result, if the fixed resistance R ₁₃ is set to, for example, 700KΩ, the maximum resistance value will be this value due to the large variation in only the variable resistance VR ₁ as in the first embodiment.
In some cases, it exceeds 700KΩ and may overlap with the lowest input, but according to the present embodiment, the fixed resistor _R14 corrects the variation so that it is small, and it does not overlap with the lowest input.

Furthermore, a fourth embodiment of the present invention will be explained with reference to FIG. In this embodiment, _the fixed resistance R ₁₃ =R ₁₄ in the third embodiment is omitted. Therefore, the fixed resistor R ₁₃ is connected to the conductive pattern PD ₃ having a length spanning the A region and the B region.
As a result, if the slider 14 is in the C area, the OFF
However, if it is in region B, only the fixed resistor _R13 is present, and the minimum input setting is made by this fixed resistor _R13 . Further, when the slider 14 is placed in the A region, the variable resistance value of the variable resistor VR ₁ and the fixed resistor R ₁₃ are placed in parallel, and the input control of the electric blower 8 is performed by the combined resistance of both. Specifically, the minimum resistance of the variable resistor VR ₁ is set to 2MΩ, and the fixed resistance R ₁₃ (=R ₁₄ )=700KΩ.

Effects of the Invention The present inventor provided a variable resistor in the operating switch section as described above to enable variable control of the input of the electric blower, but the inventor provided a minimum input setting resistor separately from the variable resistor. By setting the minimum input using this resistor, the variation in the resistance value is extremely small compared to a variable resistor, making it possible to set a stable minimum input.In this case, by including a semi-fixed resistor, the minimum input It is also possible to expand the range of use by variably adjusting the resistance of the variable resistor.Also, when changing the resistance of the variable resistor, a correction fixed resistor is connected in parallel, so the resistance variation when operating the variable resistor is kept to a minimum according to the minimum input. In this case, the minimum input setting resistance and the correcting fixed resistance can be made common, which can further simplify the process.

[Brief explanation of drawings]

Fig. 1 is an external perspective view showing a conventional example, Fig. 2 is a circuit diagram thereof, Fig. 3 is a circuit diagram showing a first embodiment of the present invention, and Fig. 4 is a diagram showing a second embodiment of the present invention. FIG. 5 is a circuit diagram showing a third embodiment of the present invention, and FIG. 6 is a circuit diagram showing a fourth embodiment of the present invention. 5... Hose proximal part, 6... Switch operation part, 7...
AC power supply, 8...Electric blower, 9...Bidirectional thyristor, 11...Gate trigger circuit, VR ₁ ...Variable resistance, R ₁₃ ...Minimum input setting resistance, VR ₂ ...Semi-fixed resistance,
R ₁₄ ...Fixed resistance for correction.

Claims (1)

[Claims] 1. An electric blower and a bidirectional thyristor are connected in series to an AC power supply, and the bidirectional thyristor is connected in series to an AC power supply, and the bidirectional thyristor In the electric blower input control circuit, a gate trigger circuit is provided to control a bidirectional thyristor, and the input of the electric blower is controlled by this bidirectional thyristor control. It is freely selectable and is provided at the lowest input setting position.
An electric blower input control circuit characterized in that when the minimum input is set, the input of the electric blower is controlled by this minimum input setting resistance, and when the input is set above the minimum input, the input of the electric blower is controlled by a resistance change of a variable resistor. 2. The electric blower input control circuit according to claim 1, wherein the minimum input setting resistance includes at least a semi-fixed resistance. 3 A gate that connects an electric blower and a bidirectional thyristor in series to an AC power source, and controls the bidirectional thyristor in response to a change in resistance caused by the operation of an operation switch section including a variable resistor provided at a hose proximal portion. In the electric blower input control circuit which is provided with a trigger circuit and controls the input of the electric blower by bidirectional thyristor control, the minimum input setting resistance can be freely selected in the operation switch section with respect to the variable resistor. A fixed resistor for correction with a resistance lower than the maximum resistance value of the variable resistor is installed in parallel with the variable resistor when the variable resistor is operated. An electric blower input control circuit characterized in that when the input is set to a minimum input or higher, the input of the electric blower is controlled by a combined resistance of a resistance change of a variable resistor and a fixed resistance for correction. 4 The minimum input setting resistance and correction fixed resistance are set in common, and when the minimum input setting is set, the input of the electric blower is controlled by this minimum input setting resistance, and when the input setting is higher than the minimum input, the resistance of the variable resistor is changed. 4. The electric blower input control circuit according to claim 3, wherein the input to the electric blower is controlled by a combined resistance of the input resistance and the minimum input setting resistance.