JPH0357720B2 - - 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 AND THE PROBLEMS FIG. 1 shows the external appearance of a conventional vacuum cleaner, in which there is a removable dust collection case 2 in the front part of the main body case 1, and the hose difference between the dust collection case 2 and the A hose 4 is inserted into the inlet 3. 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 is a current that flows through the rectifier circuit 12 and maintains the ON state, 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.

In the conventional system, a high-resistance resistor R ₁₁ to stop the electric shock is used for 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 resistance value of this variable resistor VR ₁ regulates the minimum input. In addition, in Figure 2,
SW indicates the OFF position of the variable resistor VR ₁ , whereby the electric blower 8 is stopped.
However, variable resistors have variations due to mass production, and the deviation is 10 to 15% compared to fixed resistors.
It's about double that. 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. Therefore, even if the maximum resistance value of the variable resistor is set to 700KΩ for the minimum input setting, it will vary from 490 to 910KΩ due to variations.
If it becomes about 800 to 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.

In order to overcome these drawbacks, the applicant has proposed a control circuit as shown in FIG. In this case, the operation switch unit 6 is provided with a variable resistor VR ₁ , a fixed resistor R ₁₃ as a minimum input setting resistance, and a correction fixed resistor R ₁₄ . Here, in area A, the slider 14a is the common conductive pattern PC and the resistance pattern PR of variable resistor VR ₁ .
The resistance pattern PR has a resistance value that increases from the left side to the right side in the figure, and reaches the maximum resistance value at the right end. A conductive pattern PD ₁ for connecting the fixed resistor R ₁₃ is provided on the right side beyond the maximum resistance value of the resistance pattern PR. Therefore, the fixed resistor _R13 is connected in the B region where the slider 14a contacts the common conductive pattern PC and the conductive pattern _PD1 , and the B region corresponds to the lowest input setting position.
In addition, in the C area, the slider 14a is a common conductive pattern.
It only contacts the PC and corresponds to the OFF position. A conductive pattern PD ₂ having a length corresponding to the area A is provided, and is connected to a fixed resistor R ₁₄ . Therefore, the fixed resistor _R14 is connected in parallel with the variable resistor of the variable resistor _VR1 when the slider 14a is in the A region.

In such a configuration, when the electric blower 8 is set to the lowest input, the sliders 14a and 14b are positioned in the B area. 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. In this way, the minimum input setting is made 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.
%, and the metal film type can easily be mass-produced with a tolerance of about ±0.2%, making it possible to keep the variation in minimum input extremely small and stable.

On the other hand, when the input setting is higher than the minimum input, slider 1
By slidingly displacing 4a and 14b within the A region, the resistance of the variable resistor VR ₁ is appropriately varied, and the input to the electric blower 8 is controlled in accordance with this resistance change. Here, fixed resistor R ₁₄ is variable resistor
A resistor with a resistance lower than the maximum resistance value of VR ₁ and with a small tolerance is used to correct variations in the variable resistor VR ₁ , especially variations in the maximum resistance value. For example, variable resistor VR ₁ is ±30
% tolerance width, and the tolerance width of fixed resistor _R14 is ±2%.
If the resistance value is set to about 1/3 of the maximum resistance value of the variable resistor VR ₁ , the variation can be reduced to around ±10%. More specifically, for example, if the maximum resistance value of variable resistor VR ₁ is 2MΩ, fixed resistor R ₁₄ =
Assuming 700KΩ, the variation in variable resistor VR ₁ is 1.4 to 2.6MΩ, and the variation in fixed resistor R ₁₄ is 686 to 714KΩ. As a result, the combined resistance of both has a variation of about 470 to 560KΩ with respect to the ideal value of about 518KΩ, and the variation can be suppressed to ±10% or less. This allows for example a fixed resistance R ₁₃
= 700KΩ, if only variable resistor VR ₁ is used, the maximum resistance value will be 700K due to the large variation.
In some cases, it exceeds Ω and may overlap with the lowest input, but it is corrected by the fixed resistor _R14 so that the variation is small, and it does not overlap with the lowest input.

When the electric blower 8 is to be stopped, the sliders 14a and 14b are positioned in the C area.

Here, when looking at the structure of the variable resistor VR ₁ etc., it is configured as a variable resistor 15 as shown in FIG. That is, a resistance pattern is formed on the surface of the substrate 16.
PR and conductive patterns PD ₁ and PD ₂ are formed (see Fig. 5), and a common conductive pattern PC is formed on the back side (see Fig. 6).
4a is a contact and common conductive pattern that slides on the line between resistance pattern PR and conductive pattern PD ₁
It has contacts that slide on the PC line. In addition, the slider 14b is a contact that slides on the line of conductive pattern PD ₂ and a common conductive pattern PC.
It has a contact point that slides on the line. These contact points are on the same line in the width direction of the substrate 16, and the sliders 14a and 14b are set to operate in conjunction with each other in the sliding direction by the knob 17, and the dimension l is their maximum stroke.

However, the resistance pattern on the same line
The insulation gap G between PR and the conductive pattern PD ₁ cannot be eliminated, and the insulation gap G must be at least 1 to 1.5 mm from the viewpoint of manufacturing. As a result, when the slider 14a switches between the conductive pattern _PD1 and the resistive pattern PR, it may be located in the insulation interval G, and the electric blower 8 may stop. In other words, there are positions where the switch is turned OFF other than the OFF position on the right end side. For example, if l = 30 mm, the insulation interval G will occupy about 5% of that, and an OFF state will occur in unnecessary parts.

In this regard, as shown in FIG.
4b to click position 0.
It is conceivable to set it to OFF at 1, minimum input at 1, and variable input at 2 to 5, but even such a click mechanism is not sufficient. That is, even with the click mechanism, the slider 14a may get stuck in the insulation gap G, and as a result, the electric blower 8 stops and the user decides that it is in the OFF position and leaves it unattended. The slider 14a may gradually move due to the power and turn on, causing discomfort to the user.

Purpose of the Invention The present invention has been made in view of the above points.
The purpose of the present invention is to obtain an electric blower input control circuit that can make a transition with smooth input changes while reliably eliminating the occurrence of an OFF state.

SUMMARY OF THE INVENTION The present invention provides a second conductive pattern parallel to the resistance pattern for connecting a fixed resistance for correction in an insulation interval between a resistance pattern of a variable resistor and a conductive pattern for connecting a minimum input setting resistance. By overlapping the resistance patterns and extending them to a part of the conductive pattern for connecting the minimum input setting resistance, it is possible to change the input control from the minimum input setting using the minimum input setting resistance to the combined resistance of the variable resistance and the fixed correction resistance. When making the transition, it does not become open, and it is possible to reliably prevent the occurrence of an OFF state at a position other than the OFF position.At this time, the resistance value of the second resistance pattern allows the input change to be made smooth and the transition to be made. It is composed of

Embodiment of the Invention An embodiment of the present invention will be described based on FIG. Components that are the same as those shown in FIGS. 3 to 7 are designated by the same reference numerals, and description thereof will be omitted. In this example,
The conductive pattern PD ₂ for connecting the correction fixed resistance is formed to be slightly shorter than the resistance pattern PR.
At one end thereof, a second resistance pattern _PR2 is provided which overlaps a part of the conductive pattern _PD1 for connecting the lowest input setting resistance, including the insulation interval G part.

According to such a configuration, at the lowest input setting position, the slider 14a contacts the conductive pattern PD ₁ and the common conductive pattern PC, and the fixed resistor R ₁₃ becomes connected, resulting in the lowest input setting state.

Consider a case where the sliders 14a and 14b are slid to the left to shift to variable input control. At this time, first, the slider 14a is connected to the conductive pattern PD ₁
There is a state in which the slider 14b contacts the second resistance pattern PR2 as well as the slider 14b contacts the second resistance pattern _PR2 . In other words, the fixed resistor _R14 and the variable resistor _VR2 are connected in parallel to the fixed resistor _R13 . Then, only the slider 14b contacts the second resistance pattern PR ₂ and the fixed resistance R ₁₄
and variable resistor VR ₂ are connected. After that, when passing through the insulation interval G part, the slider 14a contacts the resistance pattern PR, and the slider 14b contacts the second resistance pattern _PR2 , thereby changing the fixed resistance to the variable resistance _VR1.
The series circuit of R ₁₄ and variable resistor VR ₂ is now connected in parallel. When the slider 14a is further slid to the left, the slider 14a contacts the resistance pattern PR and the slider 14a comes into contact with the resistance pattern PR.
b contacts the conductive pattern PD ₂ , and the variable resistor VR ₁ and the fixed resistor R ₁₄ are connected in parallel. In this way, the insulation gap G does not open during the transition process before and after, and the electric blower 8 does not stop at this portion. This is slider 1
Even considering the fact that it is practically impossible to make the four contact points of 4a and 14b on the same straight line, OFF
The electric blower 8 will not stop at any other position. Furthermore, the conductive pattern PD ₂ can be formed roughly, which is advantageous in terms of manufacturing. here,
Looking at the state of input change before and after the insulation interval G section, following the lowest input due to fixed resistor _R13 , _R13・
(R ₁₄ + VR ₂ ) / R ₁₃ + R ₁₄ + VR ₂ , R ₁₄ + VR ₂ ,
It changes in the order of VR ₁・(R ₁₄ + VR ₂ )/VR ₁ + R ₁₄ + VR ₂ , and it can be set lower than the minimum input by setting variable resistor VR ₂ , so input changes can be made smoothly. , it does not cause any discomfort to the user.

Effects of the Invention As described above, the present invention provides a second conductive pattern parallel to the resistance pattern and connected to the conductive pattern for connecting a fixed resistance for correction, in the insulation interval portion that occurs between the resistance pattern and the conductive pattern for connecting the minimum input setting resistance. Since the resistor pattern overlaps and extends to a part of the conductive pattern for connecting the lowest input setting resistor, when transitioning from the lowest input setting position to variable input control using a variable resistor, a fixed resistor for correction, and a combined resistor, it is necessary to open the resistor pattern. The occurrence of the condition can be reliably prevented,
By setting the resistance value of the second resistance pattern, the input can be changed smoothly by setting the resistance value of the second resistance pattern to a state below the minimum input without having to stop the electric blower at a position other than the OFF position, which causes a strange feeling to the user. It is something that never happens.

[Brief explanation of drawings]

Fig. 1 is an external perspective view showing a conventional example, Fig. 2 is its circuit diagram, Figs. 5 is a plan view, FIG. 6 is a bottom view, FIG. 7 is a circuit diagram including a pattern state, and FIG. 8 is a circuit diagram showing an embodiment of the present invention. 4...Hose hand part, 6...Switch operation part,
7... AC power supply, 8... Electric blower, 9... Bidirectional thyristor, 11... Gate trigger circuit, 1
4a to 14b...slider, 15...variable resistor,
VR ₁ ...Variable resistance, R ₁₃ ...Minimum input setting resistance,
R ₁₄ ...Fixed resistance for correction, PR...Resistance pattern,
PD ₁ ……Conductive pattern for connecting the minimum input setting resistance,
PD ₂ ……Conductive pattern for connecting fixed resistance for correction,
PC...Common conductive pattern, PR ₂ ...Second resistance pattern, G...Insulation interval.

Claims (1)

[Claims] 1 A gate that connects an electric blower and a bidirectional thyristor in series to an AC power source, and controls the bidirectional thyristor according 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 an electric blower input control circuit that is provided with a trigger circuit and controls the input of the electric blower by bidirectional thyristor control, the lowest input setting is selectable for the variable resistor and is connected to the lowest input setting. A resistor and a fixed compensation resistor connected in parallel to the variable resistor when setting an input higher than the minimum input are provided in the operation switch section, and a resistance pattern of the variable resistor, a conductive pattern for connecting the lowest input setting resistor, and a fixed resistor for compensation connecting. A variable resistor having a conductive pattern and a common conductive pattern is provided, and the conductive pattern for connecting the minimum input setting resistance is arranged at an insulating interval on the extension of the end of the resistance pattern of the variable resistor in the resistance increasing direction. , while the conductive pattern for connecting the correction fixed resistor is parallel to the resistor pattern and has the same length, the second resistor pattern is attached to one end of the conductive pattern at the minimum distance including the insulation interval between the resistor pattern and the conductive pattern for connecting the minimum input setting resistor. The conductive pattern for connecting the input setting resistance is partially overlapped with the slider that slides on the resistance pattern, the conductive pattern for connecting the minimum input setting resistance, and the common conductive pattern, the conductive pattern for connecting the fixed resistance for correction, and the conductive pattern for connecting the fixed resistance for correction. An electric blower input control circuit characterized in that a slider sliding on a two-resistance pattern and a common conductive pattern is interlocked in the sliding direction.