JPH08131381A - Vacuum cleaner - Google Patents

Abstract

PURPOSE: To facilitate stepped selection of power by enabling the selection of the connection of a CR time constant circuit, the connection of a vacuum variable resistor or breaking thereof from circuits with a changeover switch provided at a hand operating section in a vacuum cleaner in which a motor for suction is driven with a bidirectional 3-terminal thyristor. CONSTITUTION: A motor drive control circuit has a bidirectional 3-terminal thyristor 3 connected in series to a motor 2 for suction and a commercial AC power source 4 is connected to a series circuit thus obtained. An ignition pulse is applied by a phase control circuit 5 to a gate of the bidirectional 3-terminal thyristor 3 to ignite at a time constant determined by a capacitor 6 and a resistance circuit 7, thereby energizing the motor 2. The resistance circuit 7 is provided with a changeover switch 1 allowing switching among four circuits, fixed resistors R1 and R2 and a vacuum variable resistor RN. Thus, the switching of power is accomplished by selecting any one of the positions of 'off', 'weak', 'intermediate' and 'strong' with the changeover switch 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vacuum cleaner, and more particularly to an electric vacuum cleaner capable of switching power in stages.

[0002]

2. Description of the Related Art In a conventional well-known vacuum cleaner, a suction motor is driven by a bidirectional three-terminal thyristor, and the ignition of this bidirectional three-terminal thyristor is performed by a CR and a resistor. Some are performed by an ignition pulse from a phase control circuit including a constant circuit. To adjust the power in this type of vacuum cleaner, a part of the resistance of the CR time constant circuit is made a variable resistor and is continuously adjusted, or stepwise switching adjustment is performed.

By the way, in recent years, since it is desired to increase the "maximum power" display value in a vacuum cleaner for home use, the maximum power is supplied to the intake fan motor in a zone near the load state where the maximum power is required. The control of specifications to be put in is active. Then, a primary input current detection sensor and a pressure sensor are used to detect the load necessary for this power control.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
A primary input current detection sensor or pressure sensor for adjustment
However, the load detection method requires complicated detection and control circuits.
Adjustment is time-consuming and expensive.
Was. So, in order to solve this, just a pressure sensor
Rather than changing the negative resistance, it changes its resistance value negatively.
A variable pressure resistor has been developed.
-It is possible to make adjustments. In this negative pressure variable resistor
Power adjustment by variable as shown in Fig. 7 for hand operation
Negative pressure variable resistor R to resistor VR_NConnecting in series
Can be considered. This negative pressure variable resistor R _NHas a large negative pressure
As the vacuum level increases (the degree of vacuum increases), its resistance value decreases
It is connected to the.

In this circuit, a variable resistor V for hand operation is used.
The set value of the R, CR time constant is determined by the series combined value of the negative-pressure initial value of variable resistor R _N (resistance value is large), the phase control circuit oscillates at a predetermined oscillation period, a predetermined control angle The motor is phase controlled. When the cleaning condition is such that the negative pressure becomes large, the resistance value of the negative pressure variable resistor R _N decreases, the series combined value also decreases, the CR time constant decreases, the oscillation cycle decreases, and the phase control angle of the motor also decreases. The power is advanced and the power is increased.

However, in such a circuit, regardless of the set value of the variable resistor VR for hand operation, the phase control angle of the motor fluctuates in response to a change in negative pressure at all times, resulting in a power loss. The result is that the short-circuit switch S _S for stopping the action of the negative pressure variable resistor R _N is required separately, and it is necessary to switch it one by one according to the cleaning condition.
The problem is that it is annoying.

The present invention has been made by paying attention to the above problems, and has a simple structure, in which it is easy to select power in stages, and power fluctuations are prevented in operation modes other than "strong" operation. It is an object of the present invention to provide an electric vacuum cleaner that does not occur and automatically enables only the strongest operation.

[0008]

An electric vacuum cleaner according to claim 1 of the present application drives a suction motor with a bidirectional three-terminal thyristor, and this bidirectional three-terminal thyristor. The ignition of C consists of a capacitor and a resistor
In a case where at least a part of the resistance circuit section of the CR time constant circuit is provided in the hand operation section by the firing pulse from the phase control circuit including the R time constant circuit, the resistance circuit section provided in the hand operation section is , A first resistor having a first resistance value, a negative pressure variable resistor, and a changeover switch for switching three circuits are provided, and by operating this changeover switch, the C
The connection of the first resistor to the R time constant circuit, the connection of the negative pressure variable resistor, and the disconnection of the circuit can be selected.

In this electric vacuum cleaner, when the circuit break is selected by the changeover switch, the oscillating action is stopped, that is, "off". If the changeover switch selects "first resistance",
The motor oscillates with a fixed time constant including the resistance, and the motor has a predetermined intermediate power. In contrast, "negative pressure variable resistor"
When is selected, the resistance value decreases as the negative pressure increases, and the strongest operation is automatically performed. That is, with this vacuum cleaner, one of the changeover switches can easily perform three-stage switching of "off", "weak", and "strong".

Further, the vacuum cleaner according to claim 2 is
The resistance circuit section provided in the hand operation section includes a first resistance having a first resistance value, a second resistance having a second resistance value smaller than the first resistance value, a negative pressure variable resistor, and four circuits. A changeover switch for changeover is provided, and by operating this changeover switch, connection of the first resistor to the CR time constant circuit, connection of the second resistor, connection of the negative pressure variable resistor, and disconnection of the circuit can be selected. I am trying.

In this electric vacuum cleaner, the circuit breaker, the first resistance, the second resistance, and the negative pressure variable resistor are connected to each other by the changeover switch.
One circuit is selectively selected. That is, "off",
You can switch between "weak", "medium", and "strong".

[0012]

The present invention will be described in more detail with reference to the following examples. FIG. 1 is a diagram showing an external appearance of an electric vacuum cleaner in which the present invention is implemented. This vacuum cleaner has a main body 41
, The bellows hose 42, the hand operation part 43, and the extension tube 44
And a T-shaped suction part 45. Body part 4
1 includes a suction motor, a main control circuit, a dust collecting bag, and the like.

On the surface of the hand operation unit 43, "off",
A slide switch 1 is provided which can switch the power of the motor in steps of "weak", "medium", and "strong". Figure 2
FIG. 4 is a block diagram showing an outline of a motor drive control circuit of the embodiment vacuum cleaner. In this motor drive control circuit, a bidirectional three-terminal thyristor 3 is connected in series to a suction motor 2, and a commercial AC power supply 4 is connected to this series circuit. The phase control circuit 5 includes a capacitor 6 and a resistance circuit 7, oscillates with a time constant determined by the capacitor 6 and the resistance circuit 7, applies an ignition pulse to the gate of the bidirectional three-terminal thyristor 3, and ignites. Energize the motor 2. The phase angle for energizing the motor 2 is determined by the output timing of the firing pulse. However, these circuits are already known. In this circuit, the main circuit section 10 other than the resistance circuit 7
Is stored in the main body 41, and the resistance circuit 7 is stored in the hand operation unit 43
The resistor circuit section 7 is characterized by the features of the present invention.

FIG. 3 is a circuit diagram showing the circuit connection of the resistance circuit section 7. In the figure, a changeover switch 1 capable of switching four circuits, fixed resistors R ₁ and R _2, and a negative pressure variable resistor R _N are provided, and two lead wires 8 and 9 connected to the main body 41 are provided.
In the lead wire 8 of the above, the terminal S _{a1 of} the changeover switch 1,
S _a2 , S _a3 , and S _a4 are connected, the conductor 9 and the changeover switch 1
Terminal S negative pressure variable resistor between _b1 R _N is also a series circuit of the conductors 9 and resistor R ₁ between terminals S _b3 of the switch 1 and R ₂ are connected, the connection point of the resistors R ₁ and R ₂ And the terminal S _b2 of the changeover switch 1 are connected. No terminal corresponding to the terminal S _a4 is provided. When the slide piece 1a of the changeover switch 1 is slid from right to left, the terminal S _a1 and the terminal S _b1 , the terminal S _a2 and the terminal S _b2 , and the terminal S _a3 and the terminal S _b3 are sequentially contacted, and the switch is turned on. It is like this. Terminal S
Only one _a4 is left open.

Next, here, the structure and operation of the negative pressure variable resistor will be described.
Will be described. Negative pressure resistor R _NIs shown in Figure 4.
The negative pressure introducing portion 11, the return spring 12,
Cylinder 14 with built-in piston 13 and displacement of piston 13
Axial rod 15 attached to piston 13 in the same direction
And the sliding piece 16 fixed to the shaft rod 15, and the sliding
A variable resistance portion 18 having a resistance substrate 17 in contact with the piece 16;
It is composed of A plan view of the variable resistance portion 18 is shown in FIG.
The shaded area is the resistance area.
The sliding piece 16 on the pattern corresponding to terminals B and C.
Moves left and right and the resistance value changes. Figure 6 is the equivalent
Circuit.

In the circuit of FIG. 3, when the changeover switch 1 is turned on to the terminal S _a4 , the resistance circuit section 7 connected between the conductors 8 and 9 is in an open state, and the phase control circuit 5 does not oscillate. Therefore, the motor 2 remains stopped, that is, "off". Next, the changeover switch 1 is _operated by the terminals S _a3 and S _b3.
When turned on, the series circuit of the resistors R ₁ and R ₂ is connected to the lead wire 8,
Since the phase control circuit 5 oscillates with a relatively large time constant (cycle), the motor operates "weakly" with a large phase angle.

When the changeover switch 1 is turned on to the terminals S _a2 and S _b2 , the resistor R ₂ is connected between the conductors 8 and 9, so that the phase control circuit 5 has a medium resistance value and a time constant value of medium. , The oscillation cycle is medium, the phase angle is medium, and the motor is also operated with "medium" power. When the changeover switch 1 is turned on to the terminals S _a1 and S _b1 , the negative pressure variable resistor R _N is connected between the conductors 8 and 9. A negative pressure introduction hole 11 of the negative pressure variable resistor R _N, when the suction pressure of the vacuum cleaner (vacuum) is derived, was in the cylinder deepest portion is biased to the spring 12 back in the cylinder 14 The piston 13 overcomes the pressure of the return spring 12 and moves to the left in the figure. The moving distance depends on the introduced negative pressure.

The sliding piece 16 provided at the other end of the piston rod results in sliding on the surface of the resistance substrate 17 to the left in the drawing. Explaining in FIG. 5, the conductor foil B arranged on the substrate and the sliding piece that slides across the C portions of the printed resistance bands A to C are moved laterally, so that between the terminals A and B and the terminal B. As a result, the resistance value between C and C changes to small and large, respectively. In this case, since the resistance values are connected such that the resistance value decreases as the negative pressure increases, the resistance values connected to the conductors 8 and 9 are small, the time constant is small, the oscillation cycle is small, and the phase angle is small. The phase control angle is advanced and the power is increased.

[0019]

According to the present invention, the power of the operating portion at hand is adjusted by the changeover switch, and the negative pressure variable resistor functions as the resistance of the time constant circuit of the phase control circuit only during the strongest operation. Since it is connected to the circuit, it is possible to switch between "off", "weak", "strong", etc. with a very simple configuration and operation, and at "strong", cleaning conditions that require maximum power (negative pressure is Only when the maximum value is shown), the maximum power can be automatically supplied, and stable power can be operated except for "strong". Also, even if you select "Strong" with the hand operation switch, it will be operated with a little power down under cleaning conditions where maximum power is not required, so it is possible to save power consumption more than necessary and save energy. is there.

[Brief description of drawings]

FIG. 1 is an external view of an electric vacuum cleaner in which the present invention is implemented.

FIG. 2 is a block diagram showing a schematic configuration of a drive control circuit of a suction motor of the vacuum cleaner of the embodiment.

FIG. 3 is a circuit diagram showing a circuit connection of a resistance circuit unit provided in a hand operation unit of the electric vacuum cleaner of the embodiment.

FIG. 4 is a partial cross-sectional view for explaining the structure of a negative pressure variable resistor used in the same resistance circuit unit.

FIG. 5 is a plan view for explaining a sliding portion of the negative pressure variable resistor.

FIG. 6 is a diagram showing an equivalent circuit of the negative pressure variable resistor.

FIG. 7 is a circuit diagram showing a connection example of a variable resistor and a negative pressure variable resistor which are provided in a conventional hand-side operation unit.

[Explanation of symbols]

1 slide switch 8,9 conductor R _N negative pressure variable resistor

Claims (2)

[Claims] Claim: What is claimed is: 1. A suction motor is driven by a bidirectional three-terminal thyristor, and the bidirectional three-terminal thyristor is ignited by a phase control circuit including a CR time constant circuit composed of a capacitor and a resistor. In the electric vacuum cleaner, wherein at least a part of the resistance circuit unit of the CR time constant circuit is provided in the hand operation unit, the resistance circuit unit provided in the hand operation unit is a first resistor having a first resistance value. , A negative pressure variable resistor and a changeover switch for switching three circuits are provided, and by operating this changeover switch,
An electric vacuum cleaner, wherein connection of the first resistor to the CR time constant circuit, connection of the negative pressure variable resistor, and disconnection of the circuit can be selected. 2. A suction motor is driven by a bidirectional three-terminal thyristor, and the firing of the bidirectional three-terminal thyristor is a firing pulse from a phase control circuit including a CR time constant circuit composed of a capacitor and a resistor. In the electric vacuum cleaner, wherein at least a part of the resistance circuit unit of the CR time constant circuit is provided in the hand operation unit, the resistance circuit unit provided in the hand operation unit is a first resistor having a first resistance value. , A second resistor having a second resistance value smaller than the first resistance value, a negative pressure variable resistor, and a changeover switch for switching four circuits, and the CR time constant circuit is operated by operating this changeover switch. A vacuum cleaner, wherein connection of a first resistor, connection of a second resistor, connection of the negative pressure variable resistor, and circuit disconnection can be selected.