EP0458057B1

EP0458057B1 - Method for operating a vacuum cleaner

Info

Publication number: EP0458057B1
Application number: EP91105964A
Authority: EP
Inventors: Haruo Koharagi; Kazuo Tahara; Toshiyuki Ajima; Takeshi Abe; Tsunehiro Endo; Kunio Miyashita; Yoshitaro Ishii; Fumio Jyoraku; Hisao Suka; Atusi Hosokawa; Hisanori Toyoshima; Mitsuhisa Kawamata
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1990-04-16
Filing date: 1991-04-15
Publication date: 1995-02-01
Anticipated expiration: 2011-04-15
Also published as: KR0161987B1; DE69107119D1; KR910017996A; EP0458057A1

Description

Background of the Invention:

The present invention relates to a method for operating a vacuum cleaner, in particular being applicable to a vacuum cleaner having a power brush suction nozzle body, so that the vacuum cleaner can be operated at the most optimum condition in response to the kind of the surface to be cleaned and also the kind of the suction nozzle member.
The vacuum cleaner comprises a vacuum cleaner main body and a power brush suction nozzle body having a rotary brush and being attached to the vacuum cleaner main body. The vacuum cleaner main body has a fan motor and the power brush suction nozzle body has a nozzle motor.
The present invention relates in particular to a vacuum cleaner having a control apparatus for a driving source of a vacuum cleaner main body and more particularly to a vacuum cleaner having a control apparatus for a fan motor such as a brushless motor being housed in a vacuum cleaner main body.
There are various kinds of suction nozzle members. The suction nozzle member comprises a suction nozzle member for general use, a suction nozzle member for use in a shelf and a suction nozzle member for use in a crevice. In case the power for the power brush suction nozzle body is cut-off, the power brush suction nozzle body is used in a similar manner as the general use suction nozzle member.
In general, the kind of the general use suction nozzle member including the case when the power for the power brush suction nozzle body is being cut-off, the shelf use suction nozzle member and the crevice use suction nozzle member will be judged according to the utilization of a static pressure of the vacuum cleaner.
Besides, for the power brush suction nozzle body in which the power for the nozzle motor puts to be "on" and thereby the power brush suction nozzle body is to be operated, the power brush suction nozzle body is operated by judging the utilization of a fluctuation width of a current in the nozzle motor of the power brush suction nozzle body.
In a conventional vacuum cleaner, as shown in Japanese Patent Laid-Open No. 52430/1989, the cleaning surface to be cleaned is detected in accordance with the variation of the current which flows into a nozzle motor provided in a power brush suction nozzle body, and on the basis of this result an input to a fan motor is controlled.
In the above stated prior art, there is no consideration taken, for example when the cleaning surface to be cleaned is a tatami, to the variation in the current of the nozzle motor differing in the case when the power brush suction nozzle body is being operated parallel to the arranging direction of rushes of the tatami (tatami normal order) and in the case of the power brush suction nozzle body being operated in orthogonal to the arranging direction of rushes of the tatami (tatami reverse order).
The rushes of the tatami indicates plural rushes forming the tatami. The rush is a name of a plant and the tatami is made mainly from the many number of rushes. The arranging direction of rushes of the surface of the tatami is called as the tatami normal order, the opposite direction is called the tatami reverse order.
Further, in a method for detecting the surface to be cleaned only in accordance with the variation in the current of the nozzle motor, there may be a problem of an incorrect judgment of the surface to be cleaned.
In a conventional vacuum cleaner, it has been known a technique that an AC commutator motor is used as a driving source therefor in which a triac as a control element and a pressure sensor or an air flow amount sensor are combined.
A voltage applied to the AC commutator motor is adjusted by the triac, according to the cleaning surface to be cleaned or a value detected by the pressure sensor or the air flow amount sensor, and as a result the power of the vacuum cleaner is controlled.
In the above prior art technique, various factors for indicating a load condition of the fan motor, namely an air flow amount or a static pressure, are detected through the air flow amount sensor or the pressure sensor and control the rotation speed. Accordingly, there is a problem of increased cost of the vacuum cleaner and it is necessary to have an installation space for the sensor.
In the above prior art, for example, when the surface to be cleaned is the tatami, regardless of the case when the power brush suction nozzle body is operated in parallel with an arranging direction of rushes of the tatami surface and of the case when the power brush suction nozzle body is operated in orthogonal against the arranging direction of rushes of the tatami surface, there is no consideration about the difference in the variation in the current of the nozzle motor.
Accordingly, in a system for detecting the cleaning surface to be cleaned in accordance with only the variation in the current of the nozzle motor, there exists the problem of incorrect judgement of the surface to be cleaned.
Prior art documents EP-A-0 264 728 discloses a method for operating a vacuum cleaner in response to the kind of surface to be cleaned. The method comprises the steps of starting a fan motor and increasing its rotation speed up to a rotation speed of a standby state, calculating the rotation speed of the fan motor in accordance with the receipt of a detection signal from a magnetic pole detecting circuit and carrying out a detection of the degree of clogging of a filter.
Document EP-A-0 136 357 discloses a vacuum cleaner comprising a brushless motor, a rectifying circuit, and inverter circuit comprising transistors, a resistor for detecting a load current, a magnetic pole position detecting circuit, a Hall-element, and a microcomputer consisting of a central processing unit, a read-only memory and a random access memory.

Summary of the Invention:

An object of the present invention is to provide a vacuum cleaner operating method wherein the most suitable suction force for the vacuum cleaner can be obtained automatically in response to the kind of the surface to be cleaned.
Another object of the present invention is to provide a vacuum cleaner operating method wherein the most suitable rotation speed for a rotary brush provided in a power brush suction nozzle body of the vacuum cleaner can be obtained automatically in response to a cleaning surface to be cleaned.
A further object of the present invention is to provide a vacuum cleaner operating method wherein a kind of a suction nozzle member can be discriminated automatically and thereby the most suitable suction force for the vacuum cleaner can be obtained automatically in response to the kind of the surface to be cleaned and the kind of the suction nozzle member.
A further object of the present invention is to provide a vacuum cleaner operating method wherein various factors indicating a load condition of a fan motor of a vacuum cleaner main body such as an air flow amount and a static pressure can be detected without any sensors and wherein thereby an optimum operation for the vacuum cleaner can be obtained according to the detected factors indicating the load condition of the fan motor.
A further object of the present invention is to provide a vacuum cleaner operating method wherein the most suitable suction force for the vacuum cleaner can be obtained automatically in response to the kind of the surface to be cleaned even in the case when the surface to be cleaned is a tatami.
These objects are solved in accordance with the features of claim 1. Dependent claim 2 is directed on a preferred embodiment of the invention.
When the rotary brush contacts directly the surface to be cleaned, during the cleaning operation, the variation in the current of the nozzle motor for driving the rotary brush occurs.
Further, since the size of the fluctuation width of the peak value of the current of the nozzle motor is varied regardless of the directional arrangement of the rushes of the tatami surface and the operation direction of the suction nozzle, then another surface to be cleaned can be estimated accurately. This surface to be cleaned estimation is also carried out in accordance with the magnitude of the fluctuation of the static pressure being the output of the pressure sensor.
Further, for the cleaning surface to be cleaned there exists the most suitable rotation speed for the rotary brush and under the basis of the above stated result of the surface to be cleaned estimation the rotation speed of the rotary brush is varied according to the phase control.
The various kinds of the suction nozzle including the power brush suction nozzle are used in the operation of the vacuum cleaner.
The power brush suction nozzle can be classified in accordance with the current flowing in the fan motor.
Accordingly, the power brush suction nozzle and other kinds of suction nozzles can be estimated in accordance with the magnitude of the current flowing in the fan motor.
The static pressure variation with the operation air flow amount differs in each kind of suction nozzle such as the suction nozzle for general use, the suction nozzle for shelf use and the suction nozzle for crevice use, for example, as shown in Fig. 12.
Accordingly, the suction nozzle in use can be estimated in accordance with the static pressure H as function of the air flow amount.
In response to the cleaning surface to be cleaned, the rotation speed of the rotary brush is set at the optimum condition and further in response to the cleaning surface to be cleaned and the suction nozzle in use the fan motor is operated with the constant air flow amount control, the static pressure constant control and the rotation speed, therefore the vacuum cleaner having the most suitable suction force can be obtained in response to the cleaning surface to be cleaned.
The air flow amount and the static pressure are calculated in accordance with the load current and the rotation speed of the fan motor. On the basis of the results of the calculated air flow amount and the calculated static pressure, the rotation speed command of the fan motor is determined, thereby without the pressure sensor or the wind amount sensor the most suitable suction force can be obtained in response to the load condition.
Since the rotary brush contacts directly the surface to be cleaned, during the cleaning operation, it causes the variation in the current of the nozzle motor for driving the rotary brush. Further, the fluctuation width of the peak value in the current of the nozzle motor can vary largely in response to the cleaning surface to be cleaned.
Accordingly, by detecting the fluctuation width of the peak value and under this detection the adjustment of the inputs to the fan motor and the nozzle motor, the suction force suitable for the cleaning surface to be cleaned can be obtained.
Further, by using the mean value and the fluctuation width of the peak value in the current of the nozzle motor, regardless of the arranging direction of the rushes of the tatami and the operation direction of the power brush suction nozzle body, the cleaning surface to be cleaned can be judged accurately.
Since the inputs to the fan motor and the nozzle motor are controlled, the vacuum cleaner having the most suitable suction force against the surface to be cleaned can be obtained.

Brief Description of Drawings:

Fig. 1 is a block diagram showing one embodiment of a schematic construction of a control circuit of a fan motor for use in a vacuum cleaner according to the present invention;
Fig. 2 is a block diagram showing a whole construction of the control circuit of the fan motor use in the vacuum cleaner shown in Fig. 1;
Fig. 3 is a whole construction of the vacuum cleaner having a power brush suction nozzle body in which a cross-sectional appearance of a vacuum cleaner main body is illustrated;
Fig. 4 is a partially cross-sectional view showing an internal construction of the power brush suction nozzle body attached to the vacuum cleaner main body;
Fig. 5 is a block diagram showing a zero-cross detecting circuit of an AC power source voltage;
Fig. 6A shows voltages applied to a nozzle motor;
Fig. 6B shows zero-cross signals applied to the nozzle motor;
Fig. 6C shows waveforms of an operating count timer applied to the nozzle motor;
Fig. 6D shows gate signals applied to the nozzle motor;
Fig. 7A is an electric circuitry construction for detecting a current of the nozzle motor in which an amplifier circuit and a peak hold circuit are included;
Fig. 7B is an output example of the nozzle motor current detecting circuit;
Fig. 7C is another output example of the nozzle motor current detecting circuit;
Fig. 8 shows variations of fluctuation widths of peak values of the nozzle motor current against various cleaning surfaces to be cleaned when the nozzle motor rotates at a low speed rotation;
Fig. 9 shows variations of fluctuation widths of peak values of the nozzle motor current against various cleaning surfaces to be cleaned when the nozzle motor rotates at a high speed rotation;
Fig. 10 shows variations of fluctuation widths of the static pressures against the various cleaning surfaces to be cleaned;
Fig. 11 is characteristic curves showing relations between the air flow amount Q, the static pressure P and the rotation speed N in an adaptive control model of the vacuum cleaner;
Fig. 12 are curves showing relations between the air flow amount Q and the static pressure P against the various suction nozzle members;
Fig. 13 is a schematic construction showing one embodiment of a fan motor and a control apparatus according to the present invention;
Fig. 14 is a block diagram showing one embodiment of a schematic construction of a control circuit of a brushless motor for use in the vacuum cleaner according to the present invention;
Fig. 15 is a block diagram showing a whole construction of the control circuit shown in Fig. 14;
Fig. 16 are Q - H (air flow amount - static pressure) characteristic curves of the vacuum cleaner;
Fig. 17 are curves showing a relation between the air flow amount Q and the rotation speed N and the load current;
Fig. 18 are curves showing a relation between the static pressure H and the rotation speed N;
Fig. 19 are representative operation patterns of the vacuum cleaner in which the air flow amount - the static pressure characteristic curves of the vacuum cleaner are shown;
Fig. 20 is a block diagram showing another embodiment of a schematic construction of a control circuit having a static pressure sensor according to the present invention;
Fig. 21 is a schematic construction for detecting the static pressure of the vacuum cleaner in which a static pressure amplifier is included;
Fig. 22 is a schematic construction for detecting the air flow amount of the vacuum cleaner in which a wind amount amplifier is included;
Fig. 23 is a block diagram showing another embodiment of a schematic construction of a control circuit having an air flow amount sensor according to the present invention;
Fig. 24 is a block diagram showing a schematic construction of a control circuit of the brushless motor in which the rotation speed and a DC voltage are used;
Fig. 25 is a block diagram showing a whole construction of the control circuit shown in Fig. 24;
Fig. 26 is a curve showing a relation between DC voltage E_d and a load current I_L;
Fig. 27 is an experimental data showing relations between the air flow amount and the current command / the rotation speed;
Fig. 28 is an experimental data showing relations between the air flow amount and the rotation speed / the current command;
Fig. 29 is a block diagram showing one embodiment of a schematic construction of a control circuit in the brushless motor for use in the vacuum cleaner according to the present invention;
Fig. 30 is a block diagram showing the control circuit shown in Fig. 29;
Fig. 31A is waveforms showing voltages applied to the nozzle motor;
Fig. 31B is waveforms showing currents applied to the nozzle motor;
Fig. 32A shows one output signal amplifying circuitry of a nozzle motor current detector;
Fig. 32B shows another output signal amplifying circuitry of a nozzle motor current detector;
Fig. 33 shows one output example of an amplifier;
Fig. 34 is a curve showing variations of the fluctuation widths of the load current of the nozzle motor during the operation of the suction nozzle member;
Fig. 35 is curves showing variations of the mean values of the load currents of the nozzle motor against the various cleaning surfaces to be cleaned;
Fig. 36 is curves showing variations of the fluctuation widths of the load currents of the nozzle motor against the various cleaning surfaces to be cleaned;
Fig. 37 is characteristic curves of the vacuum cleaner in which the air flow amount Q and the load current I_D, the rotation speed N and the suction power P_OUT;
Fig. 38 is function tables in response to the cleaning surfaces to be cleaned in which the clogging degree rate and the speed command N*;
Fig. 39 is characteristic curves showing the vacuum cleaner against the cleaning surfaces to be cleaned in which the air flow amount Q and the load current I_D, the rotation speed N and the suction power P_OUT; and
Fig. 40 is curves showing the fluctuation voltages V_XN and the means values V_MD of the fluctuation voltages during the low speed operation of the nozzle motor.

Description of the Invention:

Hereinafter, one embodiment according to the present invention will be explained referring to Fig. 1 - Fig. 12. In the present invention, the use of a variable speed motor is described assuming a fan motor as a driving source of a vacuum cleaner.
As the variable speed fan motor, it is conceivable an AC commutator motor in which speed is varied by controlling an input, a phase control motor, an inverter-driven induction motor, a reactance motor, or a brushless motor. In this embodiment, an example of the brushless motor employed as the fan motor will be explained, such a brushless motor has a long life because that it has no brush being accompanied with a mechanical slide, and also the brushless motor has a good control possibility.
Further in the present invention, basically a nozzle motor for driving a rotary brush being mounted on a a power brush suction nozzle body is described assuming the nozzle motor. As the nozzle motor, it is conceivable a DC magnet motor or an AC commutator motor. In this embodiment, an example of the employment of a rectifying circuit built-in type DC magnet motor for the nozzle motor will be explained.
Fig. 1 is a block diagram showing a schematic construction of a control circuit, and Fig. 2 shows a whole construction of the control circuit.
In this figure, 16 indicates an inverter control apparatus. 29 indicates an AC power source, the current from AC power source 29 is rectified in a rectifying circuit 21, and smoothed in a capacitor 22 and further supplied to a DC voltage E_d to an inverter circuit 20.
The inverter circuit 20 constitutes a 120° conductive type inverter comprising transistors TR₁-TR₆ and circulating diodes D₁-D₆ being connected in parallel to a respective transistor TR₁-TR₆. The transistors TR₁-TR₃ constitute positive arms. The transistors TR₄-TR₆ constitute negative arms. Each of period is pulse-width moderated (PWM) with an electric angle of 120°. R₁ indicates a resistor having a comparative lower value which is connected to between an emitter side of the transistor TR₄-TR₆ constituting the negative arms and a minus side of the capacitor 22.
FM indicates a brushless motor for driving a fan (hereinafter called "fan motor"), and this fan motor FM has a rotor R comprised of a double pole permanent magnet and armature windings U, V and W. A load current I_D flowing into the winding U, V or W is detected as a drop in voltage of the above resistor R₁.
A speed control circuit of the fan motor FM is constituted mainly of a magnet pole position detecting circuit 18 being detected by a Hall element 17 etc., a fan motor current detecting circuit 23 which detects the above load current I_D and amplifies it, a base driver 15 for driving the above transistors TR₁-TR₆, and a microcomputer 19 for driving the base driver 15 in accordance with a detected signal 18S which is obtained from the above detecting circuit 18. 30 indicates an operation switch which is operated by an actual operator.
Besides, 26 indicates a nozzle motor for driving a rotary brush which is provided in a power brush suction nozzle body side of a vacuum cleaner, and it is supplied an electric power according to a phase-controlling AC power source 29 by a triac (FLS) 25. 24 indicates a gate circuit of the triacs 25, 27 indicates a current detector of a load current I_N flowing to the nozzle motor 26, and 28 indicates a nozzle motor current detector for detecting and amplifying an output signal of the current detector 27.
The magnetic pole position detecting circuit 18 receives from a signal from the Hall element 17 and the rotor R generates the magnetic pole position signal 18S. This magnetic pole position signal 18S is used for the current switching of the armature windings U, V and W also used as a signal for detecting a rotation speed of the fan motor FM. The microcomputer 19 requests the speed by counting a number of the magnetic pole position signal 18S within a predetermined sampling.
The detecting circuit 23 for the load current I_D of the fan motor FM obtains the load current I_D of the fan motor FM by converting and amplifying the drop in voltage of the resistor R₁ to a DC component through a peak hold circuit.
The detecting circuit 28 for the load current I_N of the nozzle motor 26 (in which the rectifying circuit is built-in) obtains the load current I_N of the nozzle motor 26 by rectifying it and converting and amplifying an output signal of the current detector 27 to a DC component, because the output signal of the current detector 27 is the alternative current.
The microcomputer 19 includes a central processing unit (CPU) 19-1, a read only memory (ROM) 19-2 and a random access memory (RAM) 19-3, and these are connected to each other by an address bus, a data bus and a control bus which are not shown.
In ROM 19-2, programmings necessary for driving the fan motor FM are stored, for example, which are an calculation processing of a speed, a take-in processing of an operation command, a speed control processing (ASR), a current control processing (ACR), a current detecting processing of the nozzle motor 26, a current detecting processing of the fan motor FM and a static pressure detecting processing etc..
Besides, RAM 19-3 is used for reading and writing various outside data for practising the various programmings stored in the above ROM 19-2.
The transistors TR₁-TR₆ are driven respectively by the base driver 15 in response to the gate signal 19S which is processed and generated in the microcomputer 19.
The triac 25 is driven by the switching circuit 24 responding to the gate signal 19D which is processed and generated in the microcomputer 19 in accordance with a zero-cross detecting circuit 32 of AC power source 29.
A static pressure detecting circuit 31 converts the output of a pressure sensor 8 provided in the vacuum cleaner main body to a static pressure.
In the fan motor FM having the above value, since the current flowing the armature windings corresponds to an output torque of the fan motor FM, conversely, the output torque can be made variable by varying the supply current. Namely, by adjusting the supply current, the output torque of the fan motor FM can vary continuously and voluntarily. Further, according to changing a driving frequency of the inverter, the rotation speed of the fan motor FM can be varied freely.
In the vacuum cleaner of one embodiment according to the present invention, the above stated brushless type fan motor FM is used.
Next, Fig. 3 shows a whole construction of the vacuum cleaner and Fig. 4 shows a construction of the interior of the power brush suction nozzle body, respectively.
In Fig. 3 and Fig. 4, 1 indicates a surface to be cleaned, 2 a vacuum cleaner main body, 3 a hose, 4 a handy switching portion, 5 an extension pipe, 6 a rotary brush built-in type power brush suction nozzle body, 7 a filter and 8 the pressure sensor (a semiconductor pressure sensor) for detecting a clogging degree of the filter 7, respectively.
In an interior portion of a suction nozzle case 6A of the power brush suction nozzle body 6, the nozzle motor 26, a rotary brush 10 and brushes 11 attached to the rotary brush 10 are accommodated. 12 indicates a timing belt for transmitting a drive force of the nozzle motor 26 to the rotary brush 10. 13 indicates a suction extension pipe and 14 indicates rollers. A power source lead line 9 of the nozzle motor 26 is connected to a power source line 5A provided on the extension pipe 5.
With above stated construction, when the nozzle motor 26 receives the supply of the electric power and rotates, the rotary brush 10 rotates through the timing belt 12. During the rotary brush 10 rotates, the power brush suction nozzle body 6 contacts to the surface 1 to be cleaned. Since the brushes 11 are attached to the rotary brush 10, the brushes 11 contact to the surface 1 to be cleaned, thereby the load current I_N of the nozzle motor 26 becomes large.
Besides, as results of the various experiments show, since the nozzle motor 26 rotates toward one-way direction rotation, the rotary brush 10 rotates toward one direction rotation, the following facts have been ascertained in the case that the power brush suction nozzle body 6 is operated in a back and forth direction.
When the rotary brush 10 rotates and when the power brush suction nozzle body 6 is operated towards a forward direction of the power brush suction nozzle body 6, the load current I_N of the nozzle motor 26 becomes small. When the power brush suction nozzle body 6 is operated towards a reverse direction, the load current I_N of the nozzle motor 26 becomes large.
Accordingly, a method for the judgment (estimation) of the cleaning surface 1 to be cleaned utilizing the variation of the load I_N current of the nozzle motor 26 will be explained.
First of all, Fig. 5 is a zero-cross detecting circuitry for phase-controlling of the nozzle motor 26 and Fig. 6 shows an electric power waveform and a current waveform applied to the nozzle motor 26, respectively.
In Fig. 5 and Figs. 6A, 6B, 6C and 6D when AC power source 29 is a voltage V_S in Fig. 6A, a zero-cross signal 32S shown in Fig. 6B is obtained through the zero-cross detecting circuit 32 which comprises a resistor R₂, a diode D₇, a photo-coupler PS and a resistor R₃.
The microcomputer 19 works to operates a count timer shown in Fig. 6C which is synchronized with the first transition and the last transition of the zero-cross signal 32S. When the count timer becomes zero, a gate signal 19D is outputted from the microcomputer 19 to FLS 25.
As a result, the load current I_N shown in Fig. 6A flows into the nozzle motor 26, by the phase control the rotation speed of the nozzle motor 26, in other words, the input is controlled.
Figs. 7A - 7C show a detecting circuit construction of the nozzle motor 26 and an example of the output thereof.
Since the load current I_N supplied to the nozzle motor 26 is an intermittent AC current waveform as shown in Fig. 6A, a DC voltage signal V_DP is obtained through a full wave rectification amplifying circuit 28, a diode D₁₀ and a peak hold circuit 28B. During the suction nozzle operation this output signal V_DP varies between V_MX and V_MN as shown in Fig. 7A. A voltage (V_MX - V_MN) is made as a fluctuation width V_MB of the detected voltage.
Fig. 8 is a measurement result of a low speed rotation state of the nozzle motor 26 showing the fluctuation width V_MB of the detected voltage corresponding to the variation of the load current I_N of the nozzle motor 26 during the suction nozzle operation in response to the cleaning surface 1 to be cleaned.
Here, the rotation speed of the fan motor FM increases from rotation speed (1) to rotation speed (3) in turn, in other words, the suction force becomes large in turn. Further, carpets from a carpet (1) to a carpet (6) indicate lengths of the carpet downs, said downs progressively increasing in length.
In Fig. 8, it may be considered whether or not the kind of the surface 1 to be cleaned can be estimated in accordance with the fluctuation width V_MB of the detected voltage.
When the suction force of the rotation speed (1) is weak, the fluctuation width V_MB is zero in case of the floor and becomes large the tatami normal order, the tatami reverse order and the carpet in turn. The fluctuation width of the tatami reverse order is large that of the carpet (2). The fluctuation widths of the carpet (2) and the carpet (3) become similar to. Therefore, it is impossible to estimate the kind of the cleaning surface to be cleaned in accordance with merely the size of the fluctuation width V_MB.
Here, when it can pay attention to the increasing rate of the fluctuation width V_MB between the rotation speed (1) and the rotation speed (2), the increasing rate A of the tatami reserve order is smaller than the increasing rate B of the carpet (2).
Accordingly, when the nozzle motor 26 initially rotates at a low speed, in accordance with the size of the increasing rate between the fluctuation width V_MB of the detected voltage and the increasing rate of rotation from the rotation speed (1) to the rotation speed (2), it can distinguish or estimate the floor, the tatami, the carpet (1), the carpet (2) or the carpet (3) of the cleaning surface to be cleaned.
Fig. 9 is a measurement result of a high speed rotation state of the nozzle motor 26 showing the fluctuation width V_MB of the detected voltage corresponding to the variation in the load current I_N of the nozzle motor 26 during the suction nozzle operation in response to the surface to be cleaned.
In Fig. 9, when nozzle motor 26 rotates a high speed rotation, regardless of the rotation speeds (1), (2) and (3) of the fan motor FM, since the fluctuation width V_MB of the detected voltage is large the floor, the tatami, the carpet (1), the carpets (2) and (3) and the carpet (4) in turn, the kind of the cleaning surface to be cleaned can estimate in accordance with the size of the fluctuation width V_MB of the detected voltage.
Here, when the low speed rotation of the nozzle motor 26 is about 3000 rpm, then the rotation speed of the rotary brush 10 is made less than 1200 rpm, so that destruction of the surface to be cleaned during the tatami and the floor is avoided and a reduction in the noise generated is achieved.
When the high speed rotation of the nozzle motor 26 is more than 6000 rpm, then the rotation speed of the rotary brush 10 is made more than 2400 rpm, so that it can cope with the case of the carpet (the case may include the tatami).
Accordingly, during no cleaning operation, both the nozzle motor 26 and the fan motor FM rotate at low speed, and when the suction nozzle operation is detected, the initial estimation of the surface to be cleaned is performed in accordance with the fluctuation width V_MB of the detected voltage between the rotation speed (1) and the rotation speed (2) of the fan motor FM.
Next, with the above result of the surface to be cleaned estimation, the nozzle motor 26 begins to rotate at a higher speed, the estimation of the surface to be cleaned is carried out in accordance with the fluctuation width V_MB of the detected voltage. In accordance with these results of the surface to be cleaned estimation the inputs to the fan motor FM and the nozzle motor 26 are controlled automatically.
The surface to be cleaned estimation in accordance with the fluctuation width of the detected voltage which is a peak current value of the nozzle motor 26 is described in the above. Next a method for the surface to be cleaned estimation (judgment) in accordance with the output of the pressure sensor provided in the vacuum cleaner main body will be explained.
Fig. 10 show the results of the fluctuation width H_MB of the static pressure (the fluctuation width of the detected voltage corresponding to the static pressure) in response to the cleaning surface to be cleaned plotted against the rotation speed of the fan motor FM.
In Fig. 10, when the fan motor FM is rotating at speed (1), the fluctuation width H_MB of the detected voltage has an exceptional value only in the case of carpet (1), however the fluctuation widths have similar values in cases of the floor, the tatami and the carpets (2) and (3).
In the case of rotation speeds (2) and (3), the fluctuation width H_MB of the static pressure has the largest value when the surface is a tatami. Accordingly, it is impossible to distinguish the kind of the surface to be cleaned by the size of the fluctuation width H_MB of the static pressure, because of the existence of the tatami reverse order.
Here, when one pays attention to the increasing rate of the fluctuation width H_MB of the static pressure between the rotation speed (1) and the rotation speed (2) of the fan motor FM, there can be seen the facts that A of the tatami reverse order is larger than B of the carpet (2) and C of the carpet (3).
According to the above, when the surface to be cleaned is estimated in accordance with the fluctuation width H_MB of the static pressure, the fluctuation width H_MB of the static pressure during the suction nozzle operation at the rotation speed (1) is used for the standardization for estimating the surface to be cleaned. And further, at the rotation speeds (2) and (3) greater than the rotation speed (1), the fluctuation width H_MB at of the tatami normal order is made as the threshold value.
By considering further about the increasing rate of the fluctuation width H_MB of the static pressure between the rotation speed (1), the rotation speed (2) and the rotation speed (3), it is possible to distinguish and estimate and the type of the floor and the tatami or the type of the carpet.
Fig. 11 shows an operation mode of the fan motor FM. Here, the suction force P_o of the vacuum cleaner is shown by the following formula and it is proportional to the product of the wind amount Q and the static pressure H.

$P_{o} ∝ Q·H (W)$

In Fig. 11, the constant air flow amount Q ensures the necessary minimum air flow amount and static pressure of the suction nozzle portion. The static pressure becomes large in response to the clogging degree rate of the filter 7 (the rotation speed is made large in response to the clogging degree rate of the filter 7 and the constant air flow amount Q is made constant, inversely the clogging degree rate can be estimate according to the size of the static pressure).
The constant static pressure H can mitigate the adhesion between the cleaning surface to be cleaned and the suction nozzle portion. For example, even the foreign matters attach to the suction nozzle, since if the static pressure rises above a certain level, it is difficult to remove the foreign matters.
When the air flow amount decreases, since there is hardly any suction force, the rotation speed N is changed to a constant value, thereby it can save the useless power. The connection from the constant static pressure H to the constant rotation speed N is made to run along by the load characteristic of the fan.
The control values of the constant air flow amount Q and the constant static pressure H are varied in response to the cleaning surface to be cleaned. The air flow amounts Q₁-Q₅ and the static pressures H₁-H₅ correspond respectively to the cleaning surface to be cleaned, the carpet (1), the carpets (2) and (3) and the carpet (4) of the above stated cleaning surface to be cleaned estimation measurement results in accordance with the fluctuation widths of the peak values in the current of the nozzle motor 26 and the suction force is made large in order.
In the surface to be cleaned estimation in accordance with the fluctuation width of the static pressure, it can distinguish merely the kind comprising of the floor and the tatami and the kind comprising of the carpet. The constant wind amount Q and the constant static pressure H can set to be Q₂, H₂ and Q₄, H₄ in Fig. 11 respectively.
Here, with respect to the static pressure H it can employ the output of the pressure sensor 8, however with respect to the air flow amount Q it is requested in accordance with the calculation. As a method for such a calculation, it is suitable to adopt methods that use of the current and the rotation speed of the fan motor FM or use of the static pressure and the rotation speed of the fan motor FM, it is not limited to the rotation speed itself but it may adopt an information corresponding to the rotation speed.
So far, the cleaning surface to be cleaned estimation in accordance with the fluctuation width of the peak value in current and the fluctuation width of the static pressure of the nozzle motor 26 is stated. Next, a method for the estimation (judgment) of a kind of a suction nozzle member in use will be explained.
Fig. 12 is a measurement result showing a relation between the air flow amount and the static pressure about the suction nozzle for crevice use, the suction nozzle for shelf use and the suction nozzle for general use, each of suction nozzle members is a representative one.
Within the scope of the general use suction nozzle the power brush suction nozzle body is included. The distinction between the power brush suction nozzle body and other suction nozzles is performed as following.
When the instantaneous voltage under the base of the zero-cross signal is applied to the nozzle motor 26, (when the rotary brush 10 rotates during a non-drive rotation, since the operator may feel curious, the voltage for not rotating the rotary brush 10 is applied instantaneously), it is judged as the power brush suction nozzle body 6 when the current flows into the nozzle motor 26, and the other hand, when the current is not detected it is judged other suction nozzles.
Within other suction nozzles, the distinction about the crevice use suction nozzle, the shelf use suction nozzle and the general use suction nozzle, as shown in Fig. 12, in accordance with the mean value of the static pressure H against the air flow amount Q at the motion point, it can distinguish or estimate as the crevice use suction nozzle, the shelf use suction nozzle and the general use suction nozzle.
Next, a concrete control and processing contents of the microcomputer 19 will be explained referring to Fig. 1 as a main.

step 1: When the operation switch 30 assumes the "on" condition, an operation command take-in processing and a starting processing (processing 7) are carried out, and the rotation speed of the fan motor FM is increases up to the rotation speed (1) of a standby state.
step 2: The rotation speed N is calculated in accordance with the receipt of the signal 18S from the magnetic pole position detecting circuit 18 (processing 1), the air flow amount Q thereafter also termed as "wind amount Q" is calculated in accordance with the calculation of the current command I* (corresponding to the load current) of the fan motor FM (processing 12).
In accordance with the receipt of the signal 31S from the static pressure detecting circuit 31, a static pressure detecting processing (processing 13) is carried out and thereby the static pressure H is detected.
After that, the nozzle motor 26 receives the signal from the zero-cross detecting circuit 32 and to which the instantaneous current is applied, and in accordance with the receipt of the signal 24S from the nozzle motor current detecting circuit 28, thereby the nozzle motor current detecting processing (processing 2) is carried out.
Next, in the suction nozzle judgment processing (processing 14), when the nozzle motor current is detected it is judged as the power brush suction nozzle body, and when the current is not detected it is judged as another type of suction nozzle.
When another suction nozzle is judged, it is distinguished and estimated as the crevice use suction nozzle, the shelf use suction nozzle and the general use suction nozzle according to the relation between the air flow rate Q and the static pressure H (see Fig. 12).
step 3: A clogging degree detecting processing of the filter 7 (processing 5) is carried out in accordance with the relation between the static pressure H against the air flow rate Q, and thereby the clogging degree of the filter 7 is detected.
step 4: If the suction nozzle judgment reveals (processing 4) the power brush suction nozzle body, the nozzle motor 26 is driven (at low rotation speed) through the zero-cross detecting circuit 32, a phase control angle setting processing (processing 8) and a gate signal processing (processing 9), and thereby at the time of the suction nozzle operation period the fluctuation width of the peak value in the current of the nozzle motor 26, the fluctuation width of the static pressure H and the clogging degree of the filter 7 are detected.
step 5: At the stage in which the first surface to be cleaned estimation is finished, the fan motor 26 speed is increased up to the rotation speed (2), and the cleaning surface to be cleaned estimation (processing 4) is carried out under the consideration of the increasing rate between the fluctuation width of the peak value in the current of the nozzle motor 26 and the rotation speed (1), the increasing rate between the fluctuation width of the static pressure H and the rotation speed (1), and the clogging degree of the filter 7.
step 6: In accordance with the result of the surface to be cleaned estimation (processing 4) in step 4, in an adaptive control model 19A, the air flow amount (Q₁-Q₅), the static pressure (H₁-H₅) and the rotation speed N are set respectively and by changing-over these values a speed command N* is outputted.
In accordance with the receipt of the signal 23S from the fan motor current detecting circuit 23, the fan motor current detecting processing (processing 3) is carried out and the load current I_D of the fan motor FM is detected.
In accordance with the receipt of the load current I_D (processing 3), the rotation speed N (processing 1) and the speed command N*, a current command I* are outputted from the processing 11 of the speed control processing (ASR) and the current control processing (ACR).
In accordance with the receipt of the current command I*, in the gate signal generating processing (processing 10) a base driver signal 19S is outputted and thereby the fan motor FM is controlled at a desired rotation speed.
step 7: Simultaneously, in accordance with the result of the surface to be cleaned estimation (processing 4), by receiving the signal from the zero-cross detecting circuit 32 the gate angle is determined in the gate signal generating processing (processing 9).
The gate signal 19A of the triac FLS 25 for the nozzle motor 26 is outputted through the gate signal generating processing (processing 9) and the nozzle motor 26 is controlled at a desired rotation speed.
step 8: When the result of the surface to be cleaned estimation (processing 4) is the floor, the nozzle motor 26 is rotated at a slow rotation speed. And utilizing the data of two rotation speeds comprising of the rotation speed (1) of the fan motor FM and the actual rotation speed, the method for the surface to be cleaned estimation of step 5 is carried out repeatedly.
step 9: When the result of the surface to be cleaned estimation (processing 4) is the tatami or the carpet, the nozzle motor 26 is rotated at a high rotation speed.
Under the considerations of the size of the fluctuation width of the peak value in the current of the nozzle motor 26, the fluctuation width of the static pressure H and the clogging degree of the filter 7, two kinds of the surface to be cleaned estimations (processing 4) are carried out. This method for the surface to be cleaned estimation is carried out repeatedly.
step 10: In the suction nozzle judging processing (processing 4) in the step 2, when it is judged as the general use suction nozzle, as under the standard of the rotation speed (1) of the fan motor FM, and taking into the consideration of the increasing rate between the fluctuation width of the static pressure H under the actual rotation speed and the fluctuation width of the static pressure H under the rotation speed (1) and the clogging degree of the filter 7, the surface cleaned is distinguished or estimated as the floor and the tatami kind or as the carpet kind.
step 11: When the cleaning surface to be cleaned is estimated as the floor and the tatami kind in step 10, in the adaptive control model 19A, for example, the speed command N* is outputted corresponding to the wind amount Q₂, the static pressure H₂ and the rotation speed N.
Then the rotation speed of the fan motor FM is controlled in accordance with the procedures stated in step 6, and this method for the surface to be cleaned estimation of step 10 is carried out repeatedly.
step 12: When the surface to be cleaned is estimated as the carpet kind in step 10, in the adaptive control model 19A, for example, the speed command N* is outputted corresponding to the wind amount Q₂, the static pressure H₂ and the rotation speed N.
Then the rotation speed of the fan motor FM is controlled in accordance with the procedure stated in step 6, and the method for the surface to be cleaned estimation of step 10 is carried out repeatedly.
step 13: In the suction nozzle judging processing (processing 14) in step 2, when the nozzle is judged as the shelf use suction nozzle or the crevice use suction nozzle, in the adaptive control model 19A, the speed command N* is outputted corresponding to one air flow rate Q and one static pressure H or the speed command N* is outputted corresponding to two air flow rates Q and two static pressures H.

Then the rotation speed of the fan motor FM is controlled in accordance with the procedures stated in step 6, and the suction nozzle judgment is carried out repeatedly.
Further, in the processing contents of the above stated microcomputer 19, when the surface to be cleaned is the floor, the rotary brush 10 rotates at the low rotation speed, however it may step the rotation of the rotary brush 10 and may rotate again according to the size of the fluctuation width of the static pressure H.
Further, in the microcomputer 19 the driving software for the fan motor FM or the driving software for the fan motor FM and the nozzle motor 26 may be installed, and the software for the suction nozzle estimation and the surface to be cleaned estimation may be installed in another microcomputer.
Further, in the calculation of the air flow amount, in this embodiment the rotation speed and the load current are adopted, however the static pressure and the rotation information (for example, the phase control angle in a case that employment of AC commutator motor as the fan motor FM) may be adopted.
According to the above embodiment of the present invention, since the clogging degree rate of the filter 7, the kind of the suction nozzle in use and the kind of the cleaning surface to be cleaned are detected automatically and in accordance with this detection the fan motor FM and the nozzle motor 26, thereby the vacuum cleaner having a good clogging degree of the filter 7, the suction nozzle in use and the most suitable suction port according to the surface to be cleaned can be obtained automatically.
Hereinafter, another embodiment of the present invention will be explained referring to Fig. 13 - Fig. 28.
Fig. 13 is a schematic construction showing a fan motor for use in the vacuum cleaner according to one embodiment of the present invention. A fan motor comprises a variable speed motor 38 and a fan 39, by receiving a signal 41S from a speed detector 41 and a signal 42S from a current detector 42, a rotation speed and a load current are detected in a control apparatus 40.
A control apparatus for controlling the variable speed motor 38 calculates various factor indicating a load condition from the rotation speed and the load current, for example a wind amount Q and a static pressure H, and under the calculation result the fan motor 38 is operated.
As the fan motor 38, there are considered the uses for an electric fan, a blower for cooling or a vacuum cleaner etc.. In this embodiment, it will be explained as an example about the fan motor for use in the vacuum cleaner in which an operation condition is varied according to the load condition.
Further, in the present invention, one example of the wind amount or the static pressure for indicating the load condition of the vacuum cleaner as the various factors for indicating the load condition of the fan motor will be explained.
Fig. 14 is a block diagram showing a schematic construction of the control circuit, and Fig. 15 is a whole construction of the control circuit.
In Fig. 14 and Fig. 15 of this embodiment of the present invention, same numeral indicates the same or the substantially corresponding elements of Fig. 1 and Fig. 2.
In these figures, 16 indicates an inverter control apparatus for variable speed operation of a brushless motor 17. 29 indicates an AC power source, this power source 29 is rectified by a rectifying circuit 21 and smoothed in a condenser 22 and a DC voltage E_d is supplied to an inverter circuit 20.
In this kind brushless motor 17, since the current flowing into the armature windings U, V and W corresponds to an output torque of the motor 17, inversely the output torque can be varied according to varying the applied current. Namely, by adjusting the applied current the output torque of the motor 17 can be varied continuously and voluntarily, and by varying the drive frequency of the inverter the rotation speed of the motor 17 can be varied voluntarily. In the vacuum cleaner of the present invention, this kind brushless motor 17 can adopt.
Fig. 16 shows a Q-H characteristic of the vacuum cleaner using the brushless motor 17, the wind amount Q is shown in the horizontal axis and the static pressure H and the load torque T of the fan (the fan of the blower motor in the vacuum cleaner) are shown in the vertical axis.
In Fig. 16, in the Q-H characteristic of the vacuum cleaner, when the wind amount Q is small the static pressure H becomes large and when the wind amount Q is large the static pressure H becomes small. Further, the load torque T of the fan is a square curve against the wind amount Q, and this load torque T is varied according to the condition of the suction nozzle (the variation in the inflowing area of wind) not shown in the drawing.
In this kind of Q-H characteristic of the vacuum cleaner, without use of the wind amount sensor or the pressure sensor, for calculating the wind amount or the static pressure from the load condition of the brushless motor 17, there is a need for various devices.
First of all, the output P of the brushless motor 17 is expressed by the following formula:

$P = 1.027 x N x T (W) (1)$

Accordingly, the following formula is obtained.

In the formula (2), since the output P is the product ( ${P = E}_{o} ·I$
) of the induced voltage E_o and the current I, the following formula is obtained. Namely, the torque T is proportional to the motor current I.

In the similar rule in the general fluid, the relation shown in the next formula has been known.

${L∝ N}_{F} ³·D⁵ (4)$

${Q ∝ N}_{F} ·D³ (5)$

${H∝ N}_{F} ²·D² (6)$

Here, L is a shaft input (W) of the fan, Q is the wind amount (m³/min), H is the static pressure (bar). N_F is the rotation speed of the fan and D is the diameter (mm) of the runner of the fan. Since the fan and the brushless motor 17 are coupled directly, it is considered that the shaft input L and the rotation speed N_F of the fan are equal to the output P and the rotation speed N of the brushless motor 17, respectively. The above formula (4) is transformed to the next formula according to the above formula (5) and the above stated formula (6).

$P ∝ Q·N² (7)$

Herein, P is the output (W) of the brushless motor 17 and N is the motor rotation speed (rpm).
The motor shaft output P in the above formulas (7) is shown as following.

$P = E₀·I (8)$

${E₀ = K}_{ε} ·N (9)$

Here, E₀ is the induced voltage (V), K_ε is the coefficient of the induced voltage and I is the load current (A).
The wind amount Q is expressed as following by the above formula (7), the above formula (8) and the above formula (9).

Here, K is the proportional coefficient. This proportional coefficient K includes many error factors such as the blower efficiency, the motor efficiency, the air leakage from the vacuum cleaner main body and the unit volume weight variety of air due to temperature, however in this case it takes constant.
Fig. 17 shows the wind amount Q at the horizontal axis and the ratio (rotation speed / load current) of the rotation speed N and the load current I of the brushless motor 17 at the vertical axis.
As seen from Fig. 17, regardless of the rotation speed, the wind amount Q is calculated from the value of the ratio of rotation speed to load current.
Fig. 18 is a H-N characteristic for each of the wind amounts Q₁-Q₄ in a case that the static pressure H is shown at the horizontal axis and the rotation speed N is shown at the vertical axis. From this figure, the static pressure H is requested in accordance with the relation of the following formula.

$N ∝ Q·(aH + b) (11)$

Accordingly, the following formula is obtained.

Here, a is constant and b is constant.
From these results, the wind amount Q and the static pressure H for the vacuum cleaner can be calculated in accordance with the load current I and the rotation speed N of the brushless motor 17.
Fig. 19 shows the representative operation patterns (A pattern and B pattern) of the vacuum cleaner. In the Q-H characteristic shown in the figure, A pattern shows that the wind amount Q_A1 constant control is practised at the large wind amount side and, at less than the wind amount Q_A1 side the static pressure H_A1 constant control, the wind amount Q_AB constant control and the static pressure H_AB constant control are practised.
B pattern shows that the wind amount Q_B1 constant control is practised at less than the wind amount Q_A1 side and, at less than the wind amount Q_B1 the speed constant under the constant rotation speed N_B, the wind amount Q_AB constant control and the static pressure H_AB constant control are practised.
A pattern assumes the surface to be cleaned is the tatami, in which the rotation speed is reduced at more than the large wind amount Q_A1 and the motor input is squeezed to be the constant wind amount Q_A1 and, similar to under less than the small wind amount Q_AB the rotation speed is reduced and the motor input is squeezed to be the constant wind amount Q_AB.
Further, at the wind amount between the wind amount Q_A1 and the wind amount Q_AB, so as not to injure the tatami surface, the static pressure H_A1 constant control is practised, and under less than the wind amount Q_AB and less than the static pressure H_AB, the static pressure H_AB constant control is practised.
B pattern assumes the cleaning surface to be cleaned in a case of the carpet, in which the wind amount Q_B1 constant control is practised, when the rotation speed reaches to the maximum rotation speed N_B and the wind amount is less than the wind amount Q_B1 the maximum rotation speed N_B constant control is practised, thereby the maximum power for the vacuum cleaner is obtained.
Next, the control means will be explained referring to Fig. 14 and Fig. 19.
When the actual operator operates the operation switch, first of all the microcomputer 19 carries out the operation command take-in processing and the starting processing in the processing 1 and drives the brushless motor 17 to the prescribed rotation speed N₁. The change-over switch S₁ selects the speed command N₁ during the starting and when the starting is completed the output N_CMD of AQR (wind amount regulator) and AHR (static pressure regulator) in the processing is selected.
At the starting the speed command N₁ is determined, the microcomputer 19 receives the magnetic pole position signal 18S from the magnetic pole position detecting circuit 18 and carries out the gate signal generation processing in the processing 6 and the gate element of the transistors TR₁-TR₆ is determined.
By carrying out the speed calculating processing of the processing 2, the actual speed of the brushless motor 17 is calculated and in the current detecting processing of the processing 3 by receiving the signal from the current amplifier 23A the load current I_L of the brushless motor 17 is detected.
In ASR of the processing 4, the current command I_CMD is requested from the deviation ε_N between the speed command N* and the actual rotation speed N. In ACR of the processing 5, the voltage command V* is calculated from the deviation ε_I between the current command I_CMD and the load current I_L.
In the gate signal generating processing in the processing 6, by receiving the voltage command V* and the magnetic pole position signal 18S the element for gating the transistors TR₁-TR₆ is determined and a PWM signal 19S for varying the applied voltage is outputted.
When the brushless motor 17 reaches to the prescribed rotation speed N₁, the change-over switch S₁ changes over the output signal N_CMD of AQR, AHR in the processing 7.
AQR (wind amount regulator), AHR (static pressure regulator) in the processing 7 outputs the speed command N_CMD in accordance with the actual rotation speed N and the load current I_L so as to become a predetermined wind amount Q and a predetermined static pressure H, respectively, for example to be become A pattern and B pattern in Fig. 19.
For the rotation speed N becomes not the outside command but the inside command N_CMD, the brushless motor 17 determines the voltage V* and controls through ASR and ACR in the processings 4 and 5.
As stated above, in this embodiment, the brushless motor 17 is used as the drive source of the vacuum cleaner, without the use of the pressure sensor and the air flow rate sensor. Further, the air flow Q and the static pressure H are calculated in accordance with the load current I_L and the rotation speed N of the brushless motor 17, and the wind amount constant control (AQR) and the static pressure constant control (AHR) are operated according to the respective operation pattern, thereby the optimum power for the vacuum cleaner can be controlled.
In this embodiment of the present invention, the calculation for the air flow Q and the static pressure H is calculated in accordance with the rotation speed and the load current of the brushless motor 17, it may be calculated in accordance with the ratio between the rotation speed and the current command.
As shown in the experimental data in Fig. 28, it is possible to obtain the air flow rate Q in accordance with the ratio between the rotation speed and the current command. Further, in the experimental data in Fig. 27, it is possible to obtain the air flow Q in accordance with the ratio between the current command and the rotation speed.
Further, in this embodiment the calculation values of the air flow Q and the static pressure H are used for controlling the brushless motor 17, however they may also be used for indicating the load condition of the vacuum cleaner.
Further, in this embodiment, the example of the use of the brushless motor 17 as the fan motor for use in the vacuum cleaner was explained, however an AC commutator motor may equally be adopted.
Fig. 20 - Fig. 26 show another embodiment according to the present invention.
Fig. 20 is a block diagram showing a schematic construction of a control circuit including a static pressure H detector, and Fig. 21 is a schematic construction of a static pressure detection of the vacuum cleaner.
In Fig. 20, the following points differ in comparison with Fig. 14. In addition to the rotation speed N and the load current I_L, the static pressure H of the vacuum cleaner 31 is detected by a static pressure sensor 32. The static pressure is detected by the static pressure sensor 32 mounted on the vacuum cleaner 31, in the static pressure processing in the processing 8 (included in the microcomputer 19) and by receiving a signal 33S from a static pressure amplifier 33, the static pressure H of the vacuum cleaner 31 is detected.
In AQR (air flow regulator) in the processing 9, the air flow Q is calculated in accordance with the rotation speed N and the load current I_L, and in AHR (static pressure regulator) using the detected static pressure H it may output the speed command N_CMD so as to be become a predetermined air flow Q and a predetermined static pressure H, respectively, for example to be become A pattern and B pattern in Fig. 19.
Fig. 22 is a schematic construction of an air flow detection of the vacuum cleaner, and Fig. 23 is a schematic construction of a control circuit using an air flow sensor together.
In Fig. 23, the following points differ in comparison with Fig. 14. In addition to the rotation speed N and the load current I_L of the brushless motor 17, the air flow of the vacuum cleaner 31 is detected. The air flow is detected by an air flow sensor 34 mounted on the vacuum cleaner 31, and in the air flow processing in the processing 10 included in the microcomputer 19 and by receiving a signal 35S from an air flow amplifier 35, the air flow Q of the vacuum cleaner 31 is detected.
Using the detected air flow Q in AQR (wind amount regulator) in the processing 11, and in AHR (static pressure regulator) using the detected air flow Q and the rotation speed N the speed command N_CMD may be outputed so as to become a predetermined wind amount Q and a predetermined static pressure H, respectively, for example to be become A pattern and B pattern in Fig. 19.
Fig. 24 is a block diagram showing a schematic construction of a control circuit using a rotation speed N and a DC voltage E_d of the brushless motor 17, Fig. 25 is a whole construction of the control circuit, and Fig. 26 is a plotting curve showing a drooping characteristic of DC voltage E_d of the brushless motor 17 according to the load current I_L in which the load current I_L is shown at the horizontal axis and DC voltage E_d is shown at the vertical axis.
In Fig. 24 and Fig. 25, the following points differ in comparison with Fig. 14 and Fig. 15. In accordance with DC voltage E_d to be supplied to an inverter circuit 20 and the rotation speed N of the brushless motor 17, the air flow Q and the static pressure H are calculated. DC voltage E_d is detected from the resistors R₂ and R₃ of a DC voltage detecting portion 36, and in the voltage detecting processing in the processing 12 included in the microcomputer 19 and by receiving a signal 37S from a voltage amplifier 37, DC voltage E_d is detected.
In the current calculating processing in the processing 13, it is impossible to calculate directly the air flow Q under the detected DC voltage E_d. By the above reason, the load current calculation value
is requested in accordance with the relation between DC voltage E_d and the load current I_L shown in Fig. 26.
In AQR (air flow regulator) in the processing 14, the air flow Q is calculated in accordance with the load current calculation value
calculated from the rotation speed N. In AHR (static pressure regulator) the static pressure H is calculated in accordance with the calculated air flow Q and the rotation speed N, and it can output the speed command N_CMD so as to become a predetermined air flow Q and a predetermined static pressure H, respectively, for example to be become A pattern and B pattern shown in Fig. 19.
As stated above, in this another embodiment of the present invention, using the brushless motor 17 as the driving source of the vacuum cleaner 31, and in accordance with use of either the pressure sensor or the static pressure sensor and further the load current I_L and the rotation speed N of the brushless motor 17, the air flow Q or the static pressure H is calculated, and according to the operation pattern and the air flow constant control (AQR) and the static pressure constant control (AHR) are operated, thereby the optimum power for the vacuum cleaner 31 can be controlled.
Further, by detecting DC voltage E_d and in accordance with the load current calculation value
calculated from the detected DC voltage E_d and the rotation speed N, without using the pressure sensor and the air flow sensor, the air flow Q or the static pressure H is calculated by the calculation, and according to the operation pattern and the air flow constant control (AQR) and the static pressure constant control (AHR) are operated, thereby it can control the optimum power for the vacuum cleaner can be controlled.
According to the above two embodiments of the present invention, the various factors for indicating the load condition of the fan motor for use in the vacuum cleaner, namely the air flow Q and the static pressure H are calculated in accordance with the relation between the rotation speed N and the load current I_L of the brushless motor 17, under the calculation result since the rotation speed of the fan motor is adjusted, thereby the control apparatus of the fan motor being operable at the optimum power for use in the vacuum cleaner can be obtained.
Next, another embodiment according to the present invention will be explained referring to from Fig. 29 to Fig. 40.
In Fig. 29 and Fig. 30 of this embodiment, same numerals indicate the same or substantially corresponding elements shown in Fig. 1 and Fig. 2. In Fig. 29, a function table is used in the processing 6. Further in Fig. 29 and Fig. 30, the pressure sensor 8 and the static pressure detecting circuit 31 shown in Fig. 1 are not mounted on respectively.
First of all, Figs. 31A and 31B show voltages applied to the nozzle motor 26 and a current waveform.
In Fig. 31A, when the voltage V_S shown in the drawing is applied to the nozzle motor 26, since the nozzle motor 26 is a DC magnet motor having a rectifier circuit (not shown) , an intermittent current I_N having an inferior power factor shown in the drawing flows into the motor.
With respect to the above, in Fig. 31B, when comparing a nozzle motor current I_N1 indicated in a solid line when the suction nozzle does not contact the surface to be cleaned and a nozzle motor current I_N2 indicated in a dotted line when the suction nozzle 6 contacts the surface to be cleaned, accordingly a peak value of the current of the nozzle motor 26 varies largely. The deviation ΔI_N (I_N2 - I_N1) causes in the nozzle motor current in a case whether or not the suction nozzle contacts against the surface to be cleaned.
It is impossible to detect an alternating current by a microcomputer 19, so that it is necessary to convert the nozzle motor current I_N to a direct current part.
Figs. 31A and 31B show a circuit construction of the amplifier and Figs. 32A and 32B show an example of an output of the amplifier.
Fig. 32A, shows an example for the amplifier 28 comprising an amplifying element 32A, a rectifying circuit 31 and a peak hold circuit 33. The operation of this amplifier 28 is as follows: When the nozzle motor current I_N flows into the nozzle motor 26, a voltage waveform appears at both ends of the resistor R₂, which is connected to a current detector 27, corresponding to the nozzle motor current I_N.
This voltage waveform is amplified through the amplifying element 32, the peak value of the nozzle motor current I_N is converted to the direct current part through the rectifying circuit 31 and the peak hold circuit 33 and is inputted into the microcomputer 19. The output of the peak hold circuit 33, as shown in Figs. 32A and 32B, becomes a direct current voltage V_DP corresponding to the peak value of the nozzle motor current I_N.
Fig. 32B shows another embodiment of the amplifier 28, it comprises a whole wave amplifying circuit having two operable amplifiers. The output V_DP of this becomes a result similar to that of Fig. 32A.
Fig. 34 shows a detected voltage V_DP in response to the variation in a load current of the nozzle motor 26 during the power brush suction nozzle body operation. In this figure, when the power brush suction nozzle body operates at the forth and back directions, the detected voltage V_DP in response to the peak value in the load current I_N is varied between V_MN and V_MX. V_MD is mean value between the detected voltages V_MN and V_MX.
Fig. 35 shows a measurement result of the variation in the mean value of the detected voltage V_MD in response to the surface to be cleaned. In Fig. 35, (1) indicates that the nozzle motor 26 is operated with a whole-wave operation (the voltage rectified the alternating power source 29 with the whole-wave is applied to the nozzle motor 26 and the vacuum cleaner operated with the full power) and the fan motor FM such as a brushless motor is operated with the weak operation, (2) indicates that the nozzle motor 26 is operated with the whole-wave operation and the fan motor FM is operated with the strong operation, (3) indicates that the nozzle motor 26 is operated with a half-wave operation (the voltage rectified the alternative power source 29 with the half-wave is applied to the nozzle motor 26 and the vacuum cleaner operated with the half power) and the fan motor FM is operated with the weak operation, and (4) indicates that the nozzle motor 26 is operated with the half-wave operation and the fan motor FM is operated with the strong operation.
In this figure, in a case of no load corresponding to the hang-up condition of the power brush suction nozzle body, since the rotary brush is idle, the mean value V_MD of the detected voltage is small. And further, regardless becomes to be larger the sides of the half-wave operations (3) and (4) in the nozzle motor 26 than the sides of the whole-wave operations (1) and (2) in the nozzle motor 26.
The reasons why is that since the peak value of the current I_N of the nozzle motor 26 is detected the large load current I_N flows during the half-wave operations in which the rotation speed is low.
Besides, in the case that during the cleaning operation in which the power brush suction nozzle body contacts to the surface to be cleaned, regardless of the operation conditions of the nozzle motor 26 and the fan motor FM, the mean value V_MD of the detected value is made to larger in sequence the floor, the tatami and the carpet.
Further, the tatami shows that the suction nozzle is operated in parallel with the rush arranging direction (the tatami normal order) and the tatami shows that the power brush suction nozzle body is operated in orthogonal with the rush arranging direction (the tatami reverse order). Each of the numbers (a)-(c) indicates the length of the downs and it is formed to be longer in sequence from (a) to (c) in the carpet.
Herein, the following problems occur. In case that the surface to be cleaned is judged only in accordance with the mean value V_MD of the detected voltage, the mean value V_MD varies in accordance with the operation conditions of the nozzle motor 26 and the fan motor FM, and the mean value V_MD is substantially the same in the case of the tatami of the tatami reverse order surface and in the case of the carpet, and further the mean value V_MD does not vary corresponding to the length of the downs of the carpet.
For the above reasons, it is difficult to judge the kind of surface to be cleaned only in accordance with the mean value V_MD of the detected voltage.
The reason why the mean value V_MD of the detected voltage is varied against the strong and the weak operations of the fan motor FM is following: in the case of the strong operation having strong suction force, the power brush suction nozzle body adheres closely to the cleaning surface to be cleaned, the load on the rotary brush is large, and the load current I_N of the nozzle motor 26 becomes large.
Fig. 36 shows a measurement result of the variation of the fluctuation width V_MB (V_MX - V_MN) of the detected voltage in response to the surface to be cleaned, in which the numbers (1)-(4) are the same conditions shown in Fig. 35.
In this figure, the fluctuation width V_MB of the detected voltage is not affected by the operation conditions of the nozzle motor 26 and the fan motor FM. In the case of no load, the fluctuation width V_MB of the detected voltage becomes zero.
Regardless of the normal order or the reverse order of the tatami surface, the fluctuation widths V_MB of the detected voltage with respect to the surface to be cleaned increase in the sequence floor, tatami and carpet. Further in order that the tatami may be discriminated from the carpet the fluctuation width increases larger in the sequence of the lengths of the downs (a)-(c) in the carpet.
Herein, the following problems occur. Since the fluctuation widths V_MB of the detected voltage is substantially same between the floor and the tatami surface to be cleaned, only by using the fluctuation width V_MB, it is difficult to judge whether the surface is a floor or the tatami.
However, the judgment about whether the surface to be cleaned is a floor or a tatami, by using the mean value V_MD of the detected voltage shown in Fig. 35, can be obtained in addition to the operation conditions of the nozzle motor 26 and the fan motor FM.
According to the above stated results, by using together with the mean value V_MD and the fluctuation width V_MB of the detected voltage corresponding to the load current I_N of the nozzle motor 26 during the cleaning operation, the kind of surface to be cleaned can be accurately determined.
The characteristics of the vacuum cleaner are shown in Fig. 37. The horizontal axis shows the flow rate Q (m³/min) and the vertical axis shows the suction power P_OUT indicating the suction performance, the rotation speed N of the fan motor FM and the load current I_D. An area included between two of the dotted chain lines is the actual operation range.
When it becomes hardly to clog the filter, the wind amount exists in the maximum operation point, in proportion to the rate of the clogging of the filter, the operation point transfers gradually toward the left side of the graph, and when the filter is completely clogged the air flow rate reaches to the minimum operation point.
Herein, the mean value V_MD of the detected voltage V_DP receives the effect according to the above stated operation condition of the vacuum cleaner and this relates also to the clogging of the filter of the vacuum cleaner. Namely, when the filter is not clogged, since the air flow rate is large the suction force becomes strong.
When the suction force becomes strong the adhesion degree caused between the suction nozzle and the surface to be cleaned becomes large, the load of the nozzle motor 26 becomes large and accordingly the mean value V_MD becomes large. Inversely, when the filter is clogged the suction force becomes weak. When the suction force becomes weak, the adhesion degree caused between the suction nozzle and the surface to the cleaned becomes small, the load of the nozzle motor 26 becomes small and accordingly the mean value V_MD becomes small. Therefore, it is necessary to alter or correct the standard for determining the surface be cleaned in response to the air flow rate Q.
Herein, as shown in Fig. 37, the load current I_D of the fan motor FM has the close relation to the wind amount. Accordingly, by detecting the load current I_D of the fan motor FM the clogging degree of the filter is determined, and then the standard for judging the surface to be cleaned according to the variation of the load current of the nozzle motor 26 can be corrected.
Further, so as to carry out the above stated strong operation of the vacuum cleaner, namely to increase the rotation speed of the fan motor FM, it is necessary to increase the load current I_D. Inversely, during the weak operation of the vacuum cleaner since the load current I_D is small, the strong and the weak operations of the vacuum cleaner can be judged in accordance with said the load current I_D.
Next, the control means will be explained.
Fig. 38 shows a control pattern stored in ROM 19-2 of the microcomputer 19, concretely it is indicated as the function table 8 (Fig 29) which corresponds to the respective cleaning surface to be cleaned. In this figure, the horizontal axis shows the clogging degree of the filter and the vertical axis shows the speed command N*.
The rotation speed command is increased in the sequence no load, floor, tatami, carpet (a), carpet (b) and carpet (c), and is set to increase the rotation speed in proportion to the clogging degree of the filter. According to the above means, the speed command in response to the clogging degree of the filter and the surface to be cleaned can be obtained, and therefore the optimum control for the vacuum cleaner can be attained.
Next, the processing contents in the microcomputer 19 will be explained referring mainly to Fig. 29 and Fig. 30

step 1... When the operation switch 30 is in the "on" condition, the operation command take-in processing and the starting processing (processing 7) are carried out and thereby the operation commences
step 2... From the function table 8 the speed command N_o (Fig 38) on the no load is outputted, under the results of the speed calculation (processing 1) and the current detection (processing 3), the current command I* is calculated by carrying out the speed control and the current control processing (processing 9).
Under the current command I*, the transistor necessary to gate within the transistors TR₁-TR₆ and the current factor thereof are determined according to the gate signal generating processing (processing 10) and the fan motor FM increases to the rotation speed N_o. This series of the processings is called as for short, hereinafter, a motor control processing.
step 3... The nozzle motor 26 selects the operation mode (1) of the low speed rotation and is rotated by carrying out the gate signal generating processing (processing 9). The nozzle motor 26 speed increases up to the rotation speed necessary to determine the cleaning surface to be cleaned.
step 4... The current detecting processing (processing 2) of the nozzle motor 26 is carried out. And according to the mean value V_MD within the predetermined sampling period and the fluctuation width V_MB (V_MX - V_MN) of the load current the judging processing (processing 4) of the surface to be cleaned is carried out and thereby the surface to be cleaned is estimated.
step 5... Under the above estimation result of the surface to be cleaned the speed command N₁-N₅ in response to the respective surface to be cleaned is selected, thereby the motor control processing is carried out.
step 6... The load current I_D of the fan motor FM which changes under the rotation speed suitable for the respective surface to be cleaned is detected by the current detecting processing (processing 4). Under the detected value the filter clogging degree judging processing (processing 5) is carried out, and thereby the rotation speed command of the fan motor FM is corrected in response to the filter clogging degree.
step 7... Further, by adding the clogging degree of the filter, the judging processing (processing 4) of the surface to be cleaned is carried out again. Under the estimation result about the surface to be cleaned the speed command N₁-N₅ is selected.

When the surface to be cleaned is the floor or the tatami, the operation mode of the nozzle motor 26 is set to be the mode (1) (processing 8) of low rotation speed, and when it is the carpet the operation mode of the nozzle motor 26 is set to be the mode (2) (processing 8) of high rotation speed, respectively.
According to the above stated control, the surface to be cleaned is estimated or judged in accordance with the variation of the load current I_N of the nozzle motor 26, under the result the variation of rotation speeds of the nozzle motor 26 and the fan motor FM.
Further, adding the clogging degree rate of the filter, as shown in the characteristic of the vacuum cleaner in Fig. 39, the vacuum cleaner control can be obtained at the most suitable point in response to the respective surface to be cleaned.
Fig. 40 shows the variation of the load current during the suction nozzle operation in which the nozzle motor 26 rotates at low speed. In this figure, when the nozzle motor 26 rotates at low speed, there does not make much difference the mean value and the fluctuation width of the load current against the respective cleaning surface to be cleaned.
However, there exists a great difference between the no load time (corresponding to the power brush suction nozzle body hang-up condition) and the suction nozzle operation time. Accordingly, when the power brush suction nozzle body is hung up the nozzle motor 26 is made to rotate at low speed, and when the power brush suction nozzle body is in contact to the surface to be cleaned it is preferable to make the operation condition of the nozzle motor 26 to be capable of judging the surface to be cleaned.
Further, as the kind of surface to be cleaned is estimated in accordance with the mean value of the fluctuation width of the peak value in the current of the nozzle motor 26, even when the surface to be cleaned is the wooden floor, it is necessary to rotate the rotary brush. For the above reason, when the rotary brush rotates at high speed it may cause a problem to the wooden floor surface.
So the rotation speed of the rotary brush, in order not to damage the wooden floor surface, as concluded by the experiment, should be less than about 1300 rpm. Namely, by taking into consideration the reduction ratio between the rotary brush and the nozzle motor 26, it is preferable to set the rotation speed of the nozzle motor 26 to less than about 3300 rpm. In this case, the noise generated by the suction nozzle can be reduced.
Further, in the above embodiments of the present invention, the peak value employ the nozzle motor current has been rectified to the whole-wave, however it may employ the peak value employ the nozzle motor current has been rectified to the half-wave.
According to the above embodiment of the present invention, since the variation of the peak value of the load current in the nozzle motor 26 is detected, and by this detection both inputs of the fan motor FM and the nozzle motor 26 are adjusted automatically, the vacuum cleaner being capable to obtain automatically the most suitable suction force can be obtained.

Claims

A method for operating a vacuum cleaner in response to the kind of surface to be cleaned and also the kind of suction nozzle member by using a microcomputer (19), comprising the following steps:
step 1 : starting a fan motor FM (processing 7) and increasing the rotation speed up to a rotation speed 1 of a standby state;

step 2 : calculating the rotation speed N (processing 1) of the fan motor FM in accordance with the receipt of a signal (18S) from a magnetic pole detecting circuit (18),
calculating the current command I* (processing 12) of the fan motor FM and
calculating the air flow amount Q in accordance therewith,
carrying out a static pressure detecting processing (procedure 13) by means of a static pressure detecting circuit (31) to detect a static pressure H, and
starting a nozzle motor (26) and carrying out the nozzle motor current detecting processing (processing 2) and
carrying out the suction nozzle member estimation (processing 14);

step 3 : detecting the clogging degree of a filter (7) in accordance with the relation between the static pressure H against the air flow amount Q; (processing 5),

step 4 : operating the nozzle motor (26) at low speed through a zero-cross detecting circuit (32), a phase control angle setting processing (processing 8) and a gate signal generating processing (processing 9) if the suction nozzle member estimation (processing 14) reveals that the power brush suction nozzle body is attached,
detecting, at the time of the suction nozzle operation period, the fluctuation width of the static pressure H and the clogging degree of the filter (7);

step 5 : when the first surface to be cleaned estimation is finished, increasing the rotation speed of the fan motor (FM) up to a rotation speed 2 and carrying out the estimation of the surface to be cleaned (processing 4) under consideration of the increase of the fluctuation width of the peak value in the current of the nozzle motor (26) or the increase of the fluctuation width of the static pressure H and the clogging degree of the filter (7);

step 6 : by taking into account the results of step 4 setting (processing 6) the air flow amount (Q₁ - Q₅), the static pressure (H₁ - H₅) and the rotation speed N, respectively, and outputting a speed command N*, and carrying out the fan motor current detecting processing (processing 3) and detecting the load current I_D of the fan motor FM and in accordance with the detected load current I_D outputting the rotation speed N (processing 1), the speed command N* and current command I* from a speed control system (ASR) and a current control system (ACR), respectively, (processing 11), control- ling the fan motor FM at a desired rotation speed in accordance with the receipt of the current command I* in the gate signal generating processing (processing 9);

step 7 : on receiving a signal from the zero-cross detecting circuit (32) determining a gate angle in a gate signal generating processing (processing 9) for controlling the nozzle motor (26) at a desired rotation speed;

step 8 : operating the nozzle motor (26) at a low speed when the surface to be cleaned is the floor;

step 9 : operating the nozzle motor (26) at a high rotation speed when the surface to be cleaned is a tatami or a carpet, considering the fluctuation width of the peak value in the current of the nozzle motor (26), the fluctuation width of the static pressure H and the clogging degree of the filter (7), carrying out two kinds of the surface to be cleaned estimations (processing 4) and carrying out this method for the surface to be cleaned repeatedly;

step 10: estimating that the surface to be cleaned is the floor and the tatami kind or the carpet kind when the suction nozzle member judging processing (processing 14) in step 2 above is judged to be a general use suction nozzle at suction speed 1 of the fan motor FM, and taking into consideration the increase of the fluctuation width of the static pressure H under the actual rotation speed 1 and the clogging degree of the filter (7);

step 11: outputting the speed command N* corresponding to the air flow amount Q₂, the static pressure H₂ and the rotation speed N when the surface to be cleaned is estimated as the floor and the tatami in step 10, then controlling the rotation speed of the fan motor FM in accordance with the procedures stated in step 6 and carrying out the surface to be cleaned estimation of step 10 repeatedly,

step 12: outputting the speed command N* corresponding to the air flow amount Q₂, the static pressure H₂ and the rotation speed N when the surface to be cleaned is estimated as the carpet kind in step 10, then controlling the rotation speed of the fan motor FM in accordance with step 6 and carrying out the method for surface to be cleaned estimation of step 10 repeatedly; and

step 13: outputting the speed command N* corresponding to one air flow amount Q and the static pressure H or corresponding to two airflow amounts Q and two static pressures H respectively being taken at different motor speeds when the suction nozzle member is judged as a shelf use suction nozzle or a crevice use suction nozzle and controlling the rotation speed of the fan motor FM in accordance with the procedures stated in step 6 and carrying out the suction nozzle member judgement repeatedly.
A method according to claim 1, wherein in step 2
the current command (I*) is calculated with reference to the results of the speed calculation (processing 1) and the current detection (processing 3), and
the starting of the nozzle motor (26) comprises selecting the operation mode 1 for the nozzle motor (26) of slow rotation and rotating it by carrying out the gate signal generating processing and increasing the rotation speed up to the rotation speed necessary to judge the surface to be cleaned, which is estimated in accordance with a mean value V_MD within a predetermined sampling period and the fluctuation width V_MB (V_MX - V_MN) of the load current (I_D).