JP2000069787A - Vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum cleaner which controls the rotation of a motor according to the operating condition. SOLUTION: A DC motor is driven at a specified rotating speed Ni and load current IDC is detected by a current detection circuit. If the AC input current IAC obtained from the load current IDC is lower than a first reference current value IAC1, it is interpreted as an insignificant abnormality and the rotating speed of the DC motor is kept at the specified one Ni. If the AC input current IAC exceeds a second reference current value IAC2, it is interpreted as a serious abnormality and the rotation of the DC motor is stopped, When the AC input current IAC is between the first and the second reference current value IAC1 and IAC2, it is judged normal and the rotating speed of the DC motor is increased to obtain the maximum suction force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vacuum cleaner,
In particular, the present invention relates to control of an electric motor serving as a driving source for generating a suction force for sucking dust, dust, and the like.

[0002]

2. Description of the Related Art Conventionally, a vacuum cleaner has used an electric motor (electric blower) comprising a fan and an AC commutator machine as a driving source. This motor has a brush and a commutator, and the brush and the commutator slide mechanically during driving. In addition, the rectification condition becomes severe due to the recent trend toward downsizing and lightening due to high-speed rotation, and a spark may be generated from the brush. Therefore, there is a problem that the life of the brush is short.

Therefore, Japanese Patent Application Laid-Open No. 60-242827 proposes a motor using a brushless DC motor that does not use the brush. Furthermore, Tokiko 7-2
No. 8546 proposes a method for controlling the rotation speed of the electric motor.

[0004]

However, these publications do not disclose any practical aspects of a vacuum cleaner employing a brushless DC motor. That is, abnormal methods such as a method of exerting the maximum suction force of the vacuum cleaner, a case where dust, dirt, etc. are clogged in the suction port or the hose, or a case where the magnet used in the rotor of the electric motor is demagnetized. The measures to be taken have not been resolved.

[0005] In view of the above problems, an object of the present invention is to provide a vacuum cleaner which controls the electric motor in accordance with the operation state and improves the practicality.

[0006]

Means for Solving the Problems According to the present invention, there is provided a driving motor comprising: a driving motor; and a control device for controlling the driving of the motor. The control device determines an operation state from a load current generated according to the operation state. And a control unit that controls the rotation of the electric motor based on the result of the determination by the determination unit so that the number of revolutions becomes an optimum rotation speed according to the state.

Here, the discriminating means discriminates between a normal operation state and an abnormal operation state, and the control means controls the electric motor so as to obtain a maximum suction force in a normal state, and an abnormal state in an abnormal state. Perform corresponding processing.

More specifically, when the motor is driven at a relatively low rotation speed, such as at the time of starting, the current value obtained from the load current detected by the current detection means and the reference current value are determined. Compare. And the current value is the first
When the current is lower than the reference current value, it is determined that the abnormality is a minor abnormality, for example, an abnormality such as dust or dirt clogging the suction port or the hose. In this case, the rotation speed of the electric motor is maintained.

When the current value exceeds a second reference current value higher than the first reference current value, a serious abnormality is detected, for example, a magnet used in a rotor of the motor is demagnetized, or the motor rotates. It is determined that there is an abnormality such as occurrence of some trouble in the system, and in this case, the rotation of the electric motor is stopped.

Further, the current value is different from the first reference current value and the second reference current value.
Is determined to be normal when it is between the reference current values, and in this case, the rotation speed of the electric motor is increased so that the maximum suction force is obtained, and the rotation speed is increased to the maximum rotation speed at which the maximum suction force is obtained. Hold it when it reaches.

[0011] According to this configuration, the operating state such as whether the vacuum cleaner is abnormal or normal is determined from the load current, and the rotation of the electric motor is controlled at an optimum rotational speed according to the state. Also, since the motor is controlled so that the maximum suction force is obtained when it is normal, and the abnormality handling process is performed when it is abnormal,
Usability improves.

When the current value obtained from the load current is compared with the reference current value, if the reference current value is set to an appropriate value, the degree of abnormality can be determined. Since the rotation of the motor is stopped, safety is improved. Then, when it is determined that there is an abnormality, the display means displays the abnormality, so that the user can be reliably notified of the abnormal state.

The determining means calculates a current value by multiplying the value of the load current output from the current detecting means by a constant, and compares the current value with a reference current value. As described above, by increasing the load current, which is a minute signal, by multiplying the constant by a constant, it is possible to more reliably determine whether the abnormality is normal or abnormal and to perform accurate control.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 2 is a schematic configuration diagram of a vacuum cleaner according to one embodiment of the present invention. Referring to FIG. 1, in this vacuum cleaner, a bellows-shaped suction hose 2 is connected to a connection port of main body 1 via connection portion 3 having a hollow structure. An extension tube 5 is connected to the handle 4 of the suction hose 2, and the handle 4 has an operation unit 6 for setting a cleaning operation mode and a display unit 7 for displaying an operation state.
Is arranged. A suction port 8 is provided at the tip of the extension tube 5.

A dust collection chamber 9 communicating with the suction hose 2 is formed in the main body 1, and a dust collection bag 10 having a plurality of minute ventilation holes is detachably attached to the dust collection chamber 9.
Dust, dust, etc. sucked to zero are collected. An electric blower 1 having a fan 11 and a brushless DC motor (hereinafter simply referred to as “DC motor”) 12 behind the dust collection chamber 9.
3 are provided. A control circuit (control device) for driving and controlling the DC motor 12 is provided above the electric blower 13.
14 are arranged. An exhaust port 15 for discharging the sucked air is formed at a rear portion of the main body 1.
Instead of the DC motor 12, an induction motor, a reactance motor, a hysteresis motor, or the like may be applied as the motor driven by the inverter. In the figure,
16 is a caster, 17 is a wheel.

With this configuration, when the DC motor 12 is rotationally driven by the control circuit 14, dust and dirt are sucked from the suction port 8 by the suction force, and the dust and dirt are drawn together with the sucked air into the extension pipe 5 and the suction pipe. The dust is collected in the dust bag 10 of the dust chamber 9 through the hose 2. The air passes through the opening 19 formed in the inner wall 18 via the dust bag 10 and is discharged from the exhaust port 15 while cooling the DC motor 12. As a result, no fine particles of carbon dust are emitted from the main body 1 and, since a brushless DC motor is used, there is no odor caused by the brush spark.

FIG. 3 is a block diagram showing an electrical configuration of the control circuit 14. As shown in FIG. According to FIG. 3, a rectifier circuit 22 for rectifying and smoothing an AC voltage and a smoothing capacitor 23 are connected to a power plug 21 for supplying commercial power. A converter unit 24 is connected in parallel between the power plug 21 and the rectifier circuit 22 to supply a DC power voltage to a control unit and the like to be described later.

An inverter circuit 25 for supplying a DC power supply voltage for controlling the DC motor 12 is connected to a stage subsequent to the smoothing capacitor 23. Inverter circuit 25
Are six FETs (field effect transistors) T1 to T6
And a free-wheeling diode D1 to D6 connected in parallel to each of the FETs T1 to T6.

The DC motor 12 comprises a rotor 26 having a four-pole permanent magnet as a field, an armature winding 27, and a magnetic sensor (not shown) for detecting the position of the rotor 26. . The output of the magnetic sensor is connected to a position detection circuit 28 that detects the position of the rotor 26, and the position detection circuit 28 is connected to a control unit 29. The control unit 29 controls the DC motor 12 based on the position detection signal from the position detection circuit 28.
The rotation speed of is detected.

The control unit 29 controls C of the vacuum cleaner.
PU30, ROM31 and RAM32,
They are connected via an address bus, a data bus and a control bus (not shown). ROM31
Stores various processing programs for executing the operation mode of the electric vacuum cleaner and controlling the driving of the DC motor 12. The RAM 32 stores data necessary for executing various processing programs.

The control unit 29 includes an operation unit 6 and a display unit 7
Is connected, receives an operation command signal from the operation unit 6, and displays the operation state on the display unit 7 based on the processing program. In addition, the control unit 29 is connected to a rotation speed instruction circuit 33 for instructing a predetermined rotation speed of the DC motor 12 in order to determine whether the vacuum cleaner is abnormal or normal at an early stage of the operation (details will be described later). Note that the rotation speed instruction circuit 33 may be included in the operation unit 6.

Further, the control unit 29 includes each FET T1
To T6, and a pulse width modulation unit 35 that outputs a pulse width modulation signal to the drive circuit 34. The control unit 29 receives the position signal from the position detection circuit 28 and sends a control signal to the drive circuit 34 so that the DC motor 12 rotates at a predetermined rotation speed. The drive circuit 34 sends a drive signal to the FETs T1 to T6 based on an instruction from the control unit 29. in this case,
The high-side FETs T1 to T3 are energized for an electrical period of 12
(0 °), the pulse width modulation is performed by the pulse width modulation unit 35 to perform a chopper operation.

The low side FET of the inverter circuit 25
The common drain terminal of T4 to T6 has a load current I
A resistor 36 for inducing a voltage drop by _DC is connected. One end of the resistor 36 is connected to a current detection circuit 37 as current detection means for detecting a current supplied to the armature winding 27, that is, a load current IDC of the _DC motor 12.

The current detection circuit 37, as shown in FIG.
It comprises an operational amplifier circuit 38 for amplifying a signal corresponding to the voltage drop by the resistor 36, and an integrating circuit 41 for integrating the amplified signal composed of a resistor 39 and a capacitor 40.

The signal induced by the load current detecting resistor 36 is a very small signal as shown in FIG.
The signal is amplified to a detectable level using the operational amplifier circuit 38 (see FIG. 5B). Since the amplified signal is a pulse signal, it is converted into an analog signal by the integration circuit 41 (see FIG. 5C). By inputting the converted signal to an A / D port (not shown) of the CPU 30, the DC motor 1
Detecting a second load current I _DC.

The CPU 30 calculates an _AC input current I _AC of the vacuum cleaner from the load current I _DC . That is, as shown in FIG. 6, since the load current I _DC and the AC input current I _AC are in a proportional relationship, in the CPU 30, I _AC = W * I _DC
Execute Here, W is a proportionality constant. From the above formula,
The AC input current I _AC can be calculated from the load current I _DC . As described above, since the AC input current I _AC can be easily obtained by the calculation, the circuit for detecting the _AC input current I _AC can be omitted, and the cost can be reduced.

The feature of this embodiment is that an AC input current I _AC is calculated by multiplying a load signal I _DC of the DC motor 12 which is a minute signal by a proportional constant, and the calculated value of the _AC input current I _AC and the reference current value are calculated. Is determined based on the comparison result whether the vacuum cleaner is normal or abnormal, and from the determination result, the DC motor 12 is adjusted to an optimal rotation speed according to the state.
Is to control the rotation of In particular, when it is determined that the motor is normal, the rotation speed of the DC motor 12 that is proportional to the value of the _AC input current I _AC is controlled so that the maximum attractive force is obtained. Thereby, the maximum suction power of the vacuum cleaner can be obtained.

Further, by calculating the _AC input current I _AC having a relatively large value from the minute load current I _DC and comparing the _AC input current I _AC with the reference current value, the error can be reduced and the accuracy can be improved. A comparison can be made. Therefore, there is an advantage that accurate control can be performed.

FIG. 1 is a flowchart showing the control operation by the CPU 30. When a user inputs a driving command from the operation unit 6 (steps S1 and S2), the CPU 3
0 executes the command fetch process.

At the start of operation, the DC motor 12 is started (step S3) to check whether the vacuum cleaner is normal or not, and the rotation speed N of the DC motor 12 is increased to a predetermined rotation speed N.
_i (step S4). Here, the predetermined rotation speed N _i
Is a rotation speed lower than the maximum rotation speed _Nmax of the DC motor 12, and is instructed by the rotation speed instruction circuit 33. The DC motor 12 at the predetermined rotational speed N _i based on the value of the AC input current I _AC when driven, to determine the normal or abnormal vacuum cleaner.

Specifically, the CPU 30 controls the DC motor 12
If the rotational speed becomes a predetermined rotational speed N _i (Y in step S5
ES), the value of the _AC input current I _AC is calculated from the load current I _DC (step S6). Next, it is determined whether or not the value of the _AC input current I _AC is smaller than the first reference current value I _AC1 (step S7). Here, the first reference current value I
_AC1 is a value when a minor abnormality occurs, and it is experimentally confirmed that a minor abnormality occurs when the value is lower than this value. Incidentally, the first reference current value I _AC1, as shown in FIG. 7, if the change values of a predetermined number of revolutions N _i, (see dashed line line) accordingly is intended to change.

In step S7, the AC input current I _AC
Is smaller than the first reference current value I _AC1 , it is determined that the abnormality is a minor abnormality such as a state in which dust is clogged in the suction port 8 or the like. That is, suction port 8 shown in FIG. 2, the dust suction hose 2 and the extension pipe 5 is clogged, the DC motor 12 becomes a state close to idling state, a predetermined number of revolutions sufficient low even load current I _DC than normal DC in N _i electric motor 1
2 can be rotated. Thereby, it can be determined that dust is clogged in the suction port 8 or the like.

Next, the CPU 30 displays a warning on the display unit 7 indicating that the dust is clogged (step S8). Then, holding the rotational speed N of the DC motor 12 at a predetermined rotational speed N _i. The warning display allows the user to recognize that the dust is clogged, and to clean the dust in a normal state by removing the dust. In this case, a warning such as "garbage is jammed" may be issued together with the warning display.

Next, it is determined whether or not the value of the _AC input current I _AC exceeds the second reference current value I _AC2 (step S9). Here, the second reference current value I _AC2 is a value when a serious abnormality has occurred, and it has been experimentally confirmed that a severe abnormality has occurred when the value exceeds this value. . The second reference current value I _AC2
, Like the first reference current value I _AC1, if change the value of the predetermined rotational speed N _i, changes accordingly.

In step S9, the AC input current I _AC
Is greater than the second reference current value I _AC2 , it is determined that the abnormality is severe. That is, the rotor 26 of the DC motor 12
When the magnet used in the DC motor 12 is demagnetized, or when an abnormality occurs in the rotation system of the DC motor 12, unless the DC motor 12 is rotated with a drive current higher than normal, the DC motor 12 is rotated at a predetermined rotational speed N. Cannot rotate with _i . From this, it is determined that the abnormality is severe.

Next, the CPU 30 displays an abnormality on the display unit 7 (step S10). And the DC motor 1
The rotation of Step 2 is stopped (Step S11). In this case, the warning may be displayed and a sound such as "Stopped because an abnormality has occurred" may be given. As described above, by comparing the value of the _AC input current I _AC with the reference current value, an abnormality of the vacuum cleaner can be determined at the time of startup, and a highly reliable vacuum cleaner can be obtained. In addition, since the rotation is stopped in the case of a serious abnormality, a cleaner with excellent safety can be provided.

Next, when it is determined from the processing results of steps S7 and S9 that the AC input current I _AC is higher than the first reference current value I _{AC1 and} lower than the second reference current value I _AC2 , , I _AC1 <I _AC <I _AC2 (YES in step S9), the CPU 30 determines that the state of the vacuum cleaner is normal. In this case, the DC motor 1
2 is increased (Step S12). And
The rotation of the DC motor 12 is controlled so that the value of the _AC input current I _AC becomes the third reference current value I _AC3 that provides the maximum attraction force (step S13).

Here, the third reference current value I _AC3 is a current value corresponding to the maximum rotational speed N _max of the DC motor 12, and the value of the AC input current I _AC is the third reference current value I _AC3. By controlling the drive circuit 34 so as to obtain the maximum rotation speed of the DC motor 12 can be obtained. That is, the maximum suction force of the vacuum cleaner is obtained.

Next, when the AC input current I _AC exceeds the third reference current value I _AC3 (step S14), the rotation speed of the DC motor 12 is reduced (step S15), and the value of the _AC input current I _AC is reduced. Is kept equal to the third reference current value I _AC3 . Thus, the DC motor 12 can always maintain the maximum rotation speed _Nmax . In other words, the vacuum cleaner can always obtain the maximum suction force, and can perform cleaning at the maximum suction power. Then, the operation with the maximum suction force is continued until the operation stop is input by a key input (steps S16 and S17).

The third reference current value I _AC3 is set not only so as to correspond to the maximum rotational speed N _max of the DC motor 12 but also according to the operation mode from the operation unit 6. You may. For example, as the operation mode,
There is an object to be cleaned (tatami, floor, carpet, etc.) and the strength of suction (strong, medium, weak, etc.), and the third reference current value I _AC3 is set according to the maximum number of rotations according to each mode. May be.

As described above, if the vacuum cleaner is determined to be normal, the rotation speed of the DC motor 12 is increased to a suitable rotation speed according to the operation mode and is maintained, so that a good suction power is always obtained. And a vacuum cleaner with high operation efficiency can be provided.

The present invention is not limited to the above embodiment, and many modifications and changes can be made to the above embodiment within the scope of the present invention. For example, in the above embodiment, the rotation of the DC motor is controlled by calculating the AC input current from the load current of the DC motor and comparing it with the reference current. The rotation of the DC motor may be controlled by comparing the reference current with the reference current. Further, the determination as to whether the vacuum cleaner is normal or abnormal may be made not only at the time of starting as described above but also at an arbitrary timing.

[0043]

As described above, according to the present invention, the state is determined from the load current generated according to the operating state such as whether the vacuum cleaner is abnormal or normal, and the state is determined based on the determination result. Since the rotation of the electric motor is controlled at the optimum rotation speed according to the present invention, it is possible to provide a vacuum cleaner having excellent practicality. In addition, the electric motor is controlled so that the maximum suction force is obtained in a normal state, and the abnormality handling process is performed in an abnormal state.

When the current value obtained from the load current is compared with the reference current value, the degree of abnormality can be determined by setting the reference current value to an appropriate value. Since the rotation of the motor is stopped, safety is improved. In addition, when an abnormality is detected, the fact is displayed, so that the user can surely recognize the abnormality, and can immediately take an action in the case of a minor abnormality such as clogging of dust, and can use the vacuum cleaner in a healthy state. . On the other hand, when it is determined that the vacuum cleaner is normal, the maximum suction force can be obtained by increasing the rotation speed of the electric motor, so that the performance of the vacuum cleaner can be maximized.

Further, since the current value is calculated by multiplying the value of the load current by a constant, and the current value is compared with the reference current value, the current value is compared with that determined from the load signal which is a minute signal actually detected. To determine the abnormality or normal more reliably,
Accurate control can be performed. Therefore, a highly reliable vacuum cleaner can be provided.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating control of a vacuum cleaner according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a vacuum cleaner.

FIG. 3 is an electrical configuration diagram of the vacuum cleaner.

FIG. 4 is a configuration diagram of a current detection circuit.

5A and 5B show waveforms of a load current, wherein FIG. 5A shows a signal induced by a load current detection resistor, FIG. 5B shows a signal amplified by an operational amplifier circuit, and FIG. signal

FIG. 6 is a diagram showing a relationship between a load current and an AC input current.

FIG. 7 is a diagram showing a relationship between an AC input current and a rotation speed of a DC motor.

[Explanation of symbols]

7 Display unit 12 DC motor 14 Control circuit 29 Control unit 30 CPU 37 Current detection circuit I _DC load current I _AC AC input current _Ni Predetermined rotation speed

Claims (7)

[Claims] 1. A driving motor, and a control device for controlling the driving of the motor, the control device determining means for determining the operating state from a load current generated according to the operating state, and the determining means A controller that controls the rotation of the electric motor based on a result of the determination so as to achieve an optimal rotation speed according to the state. A determining means for determining a normal operation state and an abnormal operation state; controlling means for controlling the electric motor so as to obtain a maximum suction force in a normal state; The vacuum cleaner according to claim 1, wherein the vacuum cleaner performs a process. 3. A current detecting means for detecting a load current, wherein the judging means comprises: a current value obtained from the load current detected by the current detecting means and a reference current when the motor is driven at a predetermined rotation speed. The current value is lower than a first reference current value, it is determined that the abnormality is a minor abnormality. If the current value exceeds a second reference current value higher than the first reference current value, a severe abnormality is determined. The vacuum cleaner according to claim 1, wherein the vacuum cleaner is determined to be abnormal, and is determined to be normal when the current value is between the first reference current value and the second reference current value. 4. The control means maintains the rotation speed of the motor when it is determined that the abnormality is minor, stops the rotation of the motor when it is determined that the abnormality is severe, and reduces the maximum suction force when it is determined that the abnormality is normal. The vacuum cleaner according to claim 3, wherein the rotation speed of the electric motor is increased so as to be obtained. 5. The vacuum cleaner according to claim 4, wherein the control means holds the rotation speed of the electric motor when the rotation speed reaches the maximum rotation speed at which the maximum suction force is obtained. 6. The display device according to claim 2, further comprising a display unit for displaying an operation state, wherein the display unit displays an abnormality when the determination unit determines that the operation state is abnormal. An electric vacuum cleaner according to claim 1. 7. The method according to claim 3, wherein the determining means calculates a current value by multiplying a value of the load current output from the current detecting means by a constant, and compares the current value with a reference current value.
Vacuum cleaner as described.