JP4563427B2 - Vacuum cleaner - Google Patents

Description

  The present invention relates to a vacuum cleaner that uses a commutator motor (motor) having a stator (brush) and a commutator (rotor), and in particular, protects the commutator motor when an abnormal spark occurs in the commutator motor. For technology.

Conventionally, a commutator motor having a stator (brush) and a commutator (rotor) is used for an electric blower used for sucking dust with an electric vacuum cleaner (see, for example, Patent Documents 1 and 2). . In this commutator motor, a spark may be generated when the commutator is in sliding contact with the energized stator and rotates (hereinafter referred to as “abnormal spark”). When an abnormal spark occurs in the commutator motor, the temperature in the commutator motor abnormally rises, and there is a concern that the commutator motor is burned out or the components such as the stator are worn.
On the other hand, for example, Patent Documents 1 and 2 disclose a protection switch (hereinafter referred to as “temperature fuse”) that cuts off the power to the commutator motor when the temperature of the commutator motor reaches a preset abnormal temperature. It is disclosed to protect the commutator motor by providing it.
JP-A-8-168212 JP 2002-199661 A

However, as disclosed in Patent Documents 1 and 2, in the configuration in which a thermal fuse is used to protect against the occurrence of abnormal sparks in the commutator motor, until the temperature of the commutator motor reaches the set temperature of the thermal fuse, The occurrence of abnormal sparks in the commutator motor cannot be detected. For this reason, when the temperature rise of the commutator motor is slow, for example, when abnormal sparks occur intermittently, detection of the occurrence of the abnormal sparks may be delayed, and the commutator motor is protected early. There is a problem that can not be. In addition, since the thermal fuse is generally expensive, there is a problem that the cost of the vacuum cleaner increases in the configuration using the thermal fuse. In particular, in the configuration in which the electric circuit of the commutator motor is cut off by the melting of the thermal fuse, it is necessary to replace the thermal fuse every time the thermal fuse is blown, and in some cases, it is necessary to replace the entire commutator motor.
Accordingly, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a vacuum cleaner capable of realizing protection at the time of occurrence of an abnormal spark of a commutator motor as early as possible and at a low cost. There is.

In order to achieve the above object, the present invention is directed to supplying power to a commutator motor having a stator and a commutator rotating in sliding contact with the stator, and rotating a blower fan connected to the commutator motor to thereby generate dust. The maximum current value and the minimum current value at each predetermined time are defined as a change width at a predetermined time of the current on the electric circuit to which the commutator motor is connected . A difference value is detected, and it is determined whether or not a change width of the current detected at each predetermined time has reached a predetermined upper limit threshold or more, and the difference width is detected in the past predetermined number of times when the change width is detected. current variation width the number of times reaches or exceeds the upper threshold value is applied in advance to stop the commutator motor on condition that set the is less abnormal number of times or more than a predetermined number of times or the commutator motor Configured as a vacuum cleaner, characterized in that restrict. Specifically, the upper limit threshold is set in advance to detect that an abnormal spark has occurred in the commutator motor.
In the vacuum cleaner according to the present invention, by setting a value for detecting the occurrence of abnormal sparks in the commutator motor as the upper limit threshold, the occurrence of abnormal sparks in the commutator motor is controlled as in the prior art. Detection can be performed earlier than when a fuse is used. Then, the commutator motor can be protected early by stopping the commutator motor or limiting the current applied to the commutator motor on the condition of the detection. As a result, the life of the commutator motor can be extended, and as a result, the life of the electric vacuum cleaner having the commutator motor can be realized. Moreover, a general electric vacuum cleaner has a function of detecting the current of the commutator motor in order to control the commutator motor. Therefore, by utilizing this function, it is possible to protect the commutator motor when an abnormal spark occurs with a low-cost configuration as compared with a conventional configuration in which a thermal fuse is provided.
Further, when the current change width instantaneously exceeds the upper limit threshold for some reason, it is possible to prevent erroneous detection of the occurrence of an abnormal spark in the commutator motor. This can prevent unnecessary measures.
The present invention has found that when an abnormal spark occurs in the commutator motor, the change width of the current on the electric circuit of the commutator motor is significantly larger than the change width in other situations. It was made based on. Note that a significant difference from the current change width during normal operation will be described in the following embodiments.

By the way, the change width of the current on the electric circuit to which the commutator motor is connected every predetermined time is based on the output voltage value after being transformed by a transformer connected in series to the commutator motor. It is conceivable to detect. As a result, it is possible to detect whether or not an abnormal spark has occurred in the commutator motor in the control circuit on the output side of the transformer that is not affected by an overcurrent on the electric circuit to which the commutator motor is connected.
Here, when the commutator motor is operated by feeding AC power from a predetermined power source, the effective current per cycle of the AC power fed from the predetermined power source to the commutator motor. It is conceivable to detect a value and detect a difference current value between the maximum value and the minimum value of the effective current values of a plurality of cycles detected every predetermined time as a current change width. For example, when the predetermined power source is an AC power source having a frequency of 60 Hz, the difference between the maximum value and the minimum value of the effective current value of 60 cycles generated per second is detected as the change width.

Further, in response to the change in current on the electric circuit to which the commutator motor is connected reaching the upper limit threshold or more, it is confirmed that an abnormal spark has occurred in the commutator motor. A configuration for informing the user is desirable. Thereby, the user can know that an abnormal spark is generated in the commutator motor in the electric vacuum cleaner, and can take measures such as a request for maintenance.
Further, when the commutator motor is stopped on the condition that the change width of the current on the electric circuit to which the commutator motor is connected has reached the upper limit threshold or more, the specific operation set in advance is then performed. In the meantime, it is desirable to limit restart of the commutator motor. This prevents the commutator motor from being restarted in a situation where an abnormal spark is highly likely to occur in the commutator motor.

  According to the present invention, the value for detecting the occurrence of abnormal spark in the commutator motor is set as the upper limit threshold value, so that the occurrence of abnormal spark in the commutator motor is used in the conventional manner. It can be detected earlier than the case. Then, the commutator motor can be protected early by stopping the commutator motor or limiting the current applied to the commutator motor on the condition of the detection. As a result, the life of the commutator motor can be extended, and as a result, the life of the electric vacuum cleaner having the commutator motor can be realized. In addition, it is possible to protect the commutator motor when an abnormal spark occurs by using an inexpensive configuration as compared with a conventional configuration in which a thermal fuse is provided.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that the present invention can be understood. The following embodiment is an example embodying the present invention, and does not limit the technical scope of the present invention.
1 is an external view of the vacuum cleaner X according to the embodiment of the present invention, and FIG. 2 is a motor to which a commutator motor 11 provided in the vacuum cleaner X according to the embodiment of the present invention is connected. FIG. 3 and FIG. 4 are diagrams showing an example of measurement results of the current value Pd of the commutator motor 11 and its variation width Pe in the electric vacuum cleaner X according to the embodiment of the present invention, FIG. These are flowcharts which show an example of the procedure of the abnormal spark prevention process performed in the vacuum cleaner X which concerns on embodiment of this invention.
First, the schematic configuration of the electric vacuum cleaner X according to the embodiment of the present invention will be described with reference to FIG.
As shown in FIG. 1, the electric vacuum cleaner X is roughly configured to include a vacuum cleaner body portion 1, an air inlet portion 2, a connection pipe 3, a connection hose 4, an operation handle 5 and the like. The operation handle 5 is provided with operation switches for allowing the user to select whether or not the electric vacuum cleaner X is in operation and operation modes (weak, medium, strong, etc.). A display unit such as an LED for displaying the current state of the electric vacuum cleaner X is also provided in the vicinity of the operation switch, and the user can refer to the display unit to view the electric vacuum cleaner X. The state can be confirmed.

The cleaner body 1 is connected to the intake port 2 via the connection hose 4 connected to the front end of the cleaner body 1 and the connection pipe 3 connected to the connection hose 4. ing.
The vacuum cleaner body 1 includes an electric blower (not shown) having a blower fan and a commutator motor 11 (see FIG. 2) connected to the blower fan, and a commutator of the electric blower (not shown). A motor control circuit Y for controlling the motor 11 and a dust collection chamber (not shown) for storing the collected dust are incorporated. In the electric vacuum cleaner X, by supplying power to the commutator motor 11 of the electric blower (not shown), a blower fan (not shown) is rotationally driven, and dust on the floor surface is transferred from the intake port portion 3 to the connection pipe 3. And sucked into the dust collection chamber (not shown) through the connection hose 4.
The commutator motor 11 is an example of a commutator motor having a stator (brush) that is energized and a commutator (rotor) that rotates in sliding contact with the stator. In the commutator motor 11, an abnormally large spark may occur between the stator and the commutator (hereinafter referred to as “abnormal spark”). Therefore, the conventional electric blower is provided with a temperature fuse that detects overheating due to the abnormal spark and stops the motor (for example, see Patent Documents 1 and 2).
However, the vacuum cleaner X according to the embodiment of the present invention performs abnormal spark detection processing (see the flowchart in FIG. 5) described later, thereby performing abnormal spark in the commutator motor 11 of the electric blower (not shown). Therefore, the installation of a thermal fuse can be omitted. In addition, about the other structure of the said electric blower (not shown), since there is no place different from the past, description is abbreviate | omitted here.

Next, a schematic configuration of the motor drive circuit Y will be described with reference to FIG.
As shown in FIG. 2, the motor drive circuit Y includes a commutator motor 11, a triac 12, a current fuse 13, and a current transformer 14 (an example of a transformer) connected to a commercial AC power source 10 (an example of a predetermined power source). )have. A voltage detection circuit 15 and a control circuit 16 are connected to the secondary side of the current transformer 14.
The commercial AC power supply 10 supplies AC power having a frequency of 60 Hz and 100 V, for example. In the electric vacuum cleaner X, a commercial AC power supply 10 is connected to the motor drive circuit Y by connecting a power cord (not shown) to the commercial AC power supply 10. The commutator motor 11 is operated by feeding AC power from the commercial AC power supply 10. Here, the case where the commutator motor 11 is operated by AC power will be described as an example, but the present invention is similarly applied to the case where a commutator motor operated by DC power is used. It is possible.
The triac 12 is a bidirectional thyristor that controls the power supplied from the commercial AC power supply 10 to the commutator motor 11 by being controlled by the control circuit 16. Specifically, the triac 12 cuts off the power supply from the commercial AC power supply 10 to the commutator motor 11 or limits the current supplied from the commercial AC power supply 10 to the commutator motor 11. . It should be noted that the presence / absence of energization of the commutator motor 11 and the electronic components for limiting the current are not limited thereto, and various electronic components such as relays (relays) and transistors can be employed.
The current fuse 13 is for protecting electronic components on the motor drive circuit Y by cutting off the motor drive circuit Y when an overcurrent is generated on the motor drive circuit Y.

The current transformer 14 transforms the voltage supplied to the primary side at a predetermined transformation ratio and outputs it to the secondary side. The primary side of the current transformer 14 is connected to the motor drive circuit Y, and the secondary side is connected to the voltage detection circuit 15 and the control circuit 16.
The voltage detection circuit 15 converts a current induced on the secondary side of the current transformer 14 into a voltage and inputs the voltage to the control circuit 16.
The control circuit 16 includes control devices such as a CPU, a RAM, and a ROM. Based on the voltage value input from the voltage detection circuit 15, the current value on the primary side of the current transformer 14, that is, the motor. A current value flowing through the commutator motor 11 on the drive circuit Y is detected. Note that the control circuit 16 is used for one function included in a main control unit (not shown) for comprehensively controlling the electric vacuum cleaner X or for controlling the commutator motor 11. It may be an integrated circuit such as an ASIC provided separately from the illustrated one.

By the way, the current transformer 14 and the voltage detection circuit 15 are conventionally mounted in a vacuum cleaner in order to detect the current value flowing through the commutator motor 11, and in the conventional vacuum cleaner, Based on the detected current value, for example, the rotational speed control of the commutator motor 11 is performed.
On the other hand, the electric vacuum cleaner X according to the embodiment of the present invention flows to the commutator motor 11 when the control circuit 16 performs an abnormal spark detection process (see a flowchart of FIG. 5) described later. Based on the current, the occurrence of abnormal spark in the commutator motor 11 is detected. Specifically, in the abnormal spark detection process described later (refer to the flowchart of FIG. 5), the change width of the current flowing through the commutator motor 11 for one second has reached a predetermined upper limit threshold K or more. The occurrence of abnormal sparks in the commutator motor 11 is detected. This upper threshold K is set in advance to detect the occurrence of abnormal sparks in the commutator motor 11 in the electric vacuum cleaner X, and the value is determined based on other experimental results, for example. The value is not confused with.

Here, an example of a method for setting the upper limit threshold value K will be described with reference to FIGS. 3 and 4. Here, FIG. 3 shows the measurement result of the current change when the load of the commutator motor 11 is varied, and FIG. 4 shows the measurement result of the current change when an abnormal spark is generated in the commutator motor 11. ing.
3 and 4, Pd indicates an effective current value every 0.1 second flowing through the commutator motor 11 on the motor drive circuit Y, and Pe is the current value Pd per second. The change width is shown. Specifically, the change width Pe is a maximum value, a minimum value, and a difference value among the ten current values Pd detected per second. Here, the current value Pd and the change width Pe are used as indices for the control circuit 16 to determine the current value on the motor drive circuit Y and the magnitude of the change width per second of the current value. , An index value obtained by performing a predetermined calculation on the voltage value input from the voltage detection circuit 15 to the control circuit 16. The content of the predetermined calculation is determined in advance by the transformation ratio of the current transformer 14 and the parameters of the electronic components of the voltage detection circuit 15.
The control circuit 16 starts detecting the value of the change width Pe when the operation mode of the electric vacuum cleaner X is set to “strong”. Therefore, when the operation mode of the vacuum cleaner X is set to “weak” or “medium”, the change width Pe is not detected (change width Pe = 0, before t1 in FIG. And before t11 in FIG. 4).

First, the case where no abnormal spark occurs in the commutator motor 11 will be described with reference to FIG. As shown in FIG. 3, when the operation mode of the electric vacuum cleaner X is switched from “weak” to “medium” and “strong”, the electric current value Pd of the commutator motor 11 is temporarily changed in the electric vacuum cleaner X. After that, the current value Pd stabilizes at about “10000” (t1 to t2 in FIG. 3). At this time, the change width Pe changes with a very small value.
Then, the opening of the intake port 2 is closed (t2 in FIG. 3), and then the opening is suddenly opened (t3 in FIG. 3). While the opening of the air inlet 2 is closed (t2 to t3 in FIG. 3), the load of the commutator motor 11 is increased, the current value Pd is increased, and the change width Pe is slightly increased. On the other hand, when the opening of the intake port portion 2 is suddenly opened (t3 to t4 in FIG. 3), the current value Pd is rapidly increased and the change width Pe is rapidly increased to about “4200”. Thereafter, the current value Pd rapidly decreases, and the change width Pe reaches about “6000”.
Next, the opening and closing of the opening of the intake port 2 is repeatedly performed (t4 to t5 in FIG. 3). At this time, the current value Pd repeatedly increases and decreases, and the change width Pe changes at about “100 to 4000” which is larger than the normal time (t1 to t2 in FIG. 3) (t4 to FIG. 3). t5).
That is, in the electric vacuum cleaner X, when the opening of the intake port 2 is closed and then suddenly opened, the change width Pe temporarily reaches “6000”. The change width Pe changes below “4000”.

Next, the case where an abnormal spark occurs in the commutator motor 11 will be described with reference to FIG. As shown in FIG. 4, when the operation mode of the vacuum cleaner X is switched from “weak” to “medium” and “strong”, as in the case where no abnormal spark occurs (FIG. 3), In the electric vacuum cleaner X, the current value Pd of the commutator motor 11 temporarily rises rapidly.
Thereafter, when an abnormal spark occurs in the commutator motor 11, the current value Pd is rapidly changed. Therefore, the change width Pe is larger than that in the case where no abnormal spark is generated in the commutator motor 11 and changes in a state exceeding “4000”.
Thus, it was found that the change width Pe is greatly different between the case where no abnormal spark is generated in the commutator motor 11 and the case where the abnormal spark is generated. Therefore, in the present embodiment, an upper limit threshold value K for detecting that an abnormal spark is generated in the commutator motor 11 is set to “5000” (see FIGS. 3 and 4). This value of “5000” is set to balance the early detection of the occurrence of abnormal spark in the commutator motor 11 and the prevention of erroneous detection. Here, the case where the upper limit threshold value K is set to a value of “5000”, which is less likely to reach when no abnormal spark has occurred in the commutator motor 11, will be described as an example. However, the present invention is not limited to this, as long as it can determine whether or not an abnormal spark has occurred in the commutator motor 11.

Hereinafter, an example of an abnormal spark detection process performed by the control circuit 16 in accordance with a predetermined control program in the electric vacuum cleaner X will be described with reference to the flowchart of FIG. In the figure, S1, S2,... Represent processing procedure (step) numbers.
The abnormal spark detection processing is executed when the electric vacuum cleaner X is operated and the commutator motor 11 is operating, and the operation mode of the electric vacuum cleaner X is “strong”. . Therefore, as described above, when the operation mode of the vacuum cleaner X is set to “weak” or “medium”, the change width Pe is not detected and is 0 (before t11 in FIG. 4). . This is because when the operation mode of the electric vacuum cleaner X is “strong” and the rotation speed of the commutator motor 11 is high, there is a high possibility that an abnormal spark is generated in the commutator motor 11, and “weak”. If the rotation speed of the commutator motor 11 is low, the possibility is low. Of course, the abnormal spark detection process may be executed whenever the commutator motor 11 is operating regardless of the operation mode.
In the abnormal spark detection process, the control circuit 16 first executes a process for detecting a change width ΔI per second of the current flowing through the commutator motor 11 in the motor drive circuit Y in steps S1 to S3. To do. Here, the control circuit 16 when executing such processing corresponds to a current change width detecting means. In the present embodiment, the case where the presence or absence of occurrence of an abnormal spark in the commutator motor 11 is determined based on the change width of the current flowing through the commutator motor 11 will be described as an example. You may judge based on the variation width of the electric power supplied to the motor 11.

(Steps S1 to S3)
Specifically, in step S1, the effective current value flowing through the commutator motor 11 is detected by the control circuit 16 ten times at intervals of 0.1 second in one second (an example of a predetermined time). As described above, the effective current value flowing through the commutator motor 11 is detected based on the voltage value output from the voltage detection circuit 15 after being transformed by the current transformer 14.
Then, the control circuit 16 performs an operation for calculating a difference value between the maximum current value Imax and the minimum current value Imin among the effective current values detected in step S1 (Imax−Imin), The difference value is stored in the internal memory as a change width ΔI _n (n: number of detections) (step S2). The number of detections n is initially set to “1” by the control circuit 16 at the start of the abnormal spark detection process, and is incremented by 1 each time the step S1 is executed (S3).
Here, in the present embodiment, the execution current value is detected ten times at 0.1 second intervals per second in the abnormal spark detection processing, but the present invention is not limited to this. For example, it is conceivable to detect an effective current value for each cycle of AC power supplied from the commercial AC power supply 10 to the commutator motor 11. In this case, may be detected difference current value of the maximum value and the minimum value of the effective current value of the detected plurality of cycles per second as the variation width [Delta] I _n the current. For example, in the present embodiment, since the commercial AC power supply 10 supplies AC power having a frequency of 60 Hz, the difference between the maximum value and the minimum value of the effective current value of 60 cycles generated in one second is the above-described difference. It is calculated as the change width ΔI _n .

(Step S4)
Next, in step S4, the control circuit 16 determines that the change range ΔI _{n to} ΔI _n-10 of the past 10 times (an example of a predetermined number of times) has reached the preset upper limit threshold K or more. It is determined whether there is more than one (an example of the number of abnormalities).
Here, when it is determined that there are three or more that have reached the upper limit threshold K or more (Yes side of S4), it is determined that an abnormal spark has occurred in the commutator motor 11, and processing is performed. Proceeds to step S5. If it is determined that the number that has reached the upper limit threshold K or more is less than 3 (No in S4), the process returns to Step S1.

As described above, the upper limit threshold value K is a value serving as an index for detecting the occurrence of an abnormal spark in the commutator motor 11 and is set based on a result of an experiment performed in advance. Is. In the present embodiment, the upper threshold K is set to “5000” (see FIGS. 3 and 4). Therefore, in the measurement example shown in FIG. 4, at the time when the change width Pe in the past 10 times (10 seconds from t21 to t22 in FIG. 4) reaches “5000” three times or more (t22 in FIG. 4), It is detected that an abnormal spark has occurred in the commutator motor 11. On the other hand, in the measurement example shown in FIG. 3, the change width Pe instantaneously exceeds “5000”, but the change width Pe of the past 10 times does not reach “5000” three times or more. The occurrence of abnormal sparks in the commutator motor 11 is not detected.
Thus, the abnormal spark detection process, of the variation ΔI _n ~ΔI _n-10 of the last 10 times, occurrence of an abnormal sparks on condition that those reached over the upper threshold value K is more than three due to the process to sense the variation [Delta] I _n can be prevented from being erroneously detected occurrence of an abnormal sparks when rose instantaneously, unnecessary treatment of step S5 and subsequent later Execution can be prevented. However, the present invention is not limited to this, and, for example, the upper threshold K is set to a large value such as “7000” or “8000” that is considered not to be reached when no abnormal spark is generated in the commutator motor 11. In another embodiment, it is conceivable to detect the occurrence of an abnormal spark when the value is exceeded even once.

(Step S5)
When it is detected in step S4 that an abnormal spark is generated in the commutator motor 11 (Yes side of S4), in the subsequent steps S5 to S7, a measure for the occurrence of the abnormal spark is executed.
First, in step S5, the control circuit 16 controls the triac 12 to cut off the motor drive circuit Y and cut off power supply from the commercial AC power supply 10 to the commutator motor 11. , The operation of the commutator motor 11 is stopped. Here, the control circuit 16 when executing such processing corresponds to an abnormality handling means.
As a result, overheating due to the occurrence of abnormal sparks in the commutator motor 11 can be prevented, and wear of internal components such as a stator in the commutator motor 11 and burning of the commutator motor 11 can be prevented. This can extend the service life. Further, since a temperature fuse is not used as in the prior art, the temperature fuse can be reduced and the cost can be reduced. Furthermore, with the thermal fuse, the commutator motor 11 cannot be stopped until the commutator motor 11 is overheated, but in the abnormal spark detection process, an abnormal spark has started to occur in the commutator motor 11. Sometimes this can be detected early, and the commutator motor 11 can be stopped before the commutator motor 11 is overheated.
Here, the commutator motor 11 is stopped as an example of a measure against the occurrence of abnormal spark. However, limiting the current applied to the commutator motor 11 is also considered as another embodiment. It is done. This is because the abnormal spark may be eliminated by limiting the current applied to the commutator motor 11.

(Step S6)
Next, in step S6, the control circuit 16 executes a process for notifying the user of the electric vacuum cleaner X that an abnormal spark has occurred in the commutator motor 11. The notification at this time is performed by, for example, LED display on a display unit (not shown) of the operation handle 5, voice output from a speaker (not shown), buzzer output, or the like. Here, the control circuit 16 when executing the notification processing corresponds to an abnormal spark generation notification means.
Thereby, the user of the electric vacuum cleaner X can know the occurrence of abnormal sparks in the commutator motor 11 and can take measures such as a maintenance request for the electric vacuum cleaner X.

(Step S7)
By the way, if the commutator motor 11 is restarted immediately after the abnormal spark is generated and the commutator motor 11 is stopped in the step S5, there is a possibility that the abnormal spark is generated again in the commutator motor 11. Is expensive.
Therefore, in step S7, the control circuit 16 determines whether or not the specific operation has been performed, and waits for processing until the specific operation is performed (No side of S7). Thereby, in the abnormal spark detection process, the restart of the commutator motor 11 is restricted until the preset specific operation is performed after the commutator motor 11 is stopped in the step S5. . Here, the control circuit 16 when executing such a restriction process corresponds to a restart restriction means.
Here, it can be considered as an example that the specific operation is plugging / unplugging the power cord of the vacuum cleaner X. In this case, the control circuit 16 limits the restart of the commutator motor 11 until the power cord of the electric vacuum cleaner X is connected / disconnected and the operation of the electric vacuum cleaner X is reset once. Will be processed as follows. In addition, the specific operation may be an operation such as a long press of a predetermined button or a press of a button for forced release.
Thus, in the electric vacuum cleaner X, once the occurrence of abnormal spark is detected and the commutator motor 11 is stopped, the commutator motor 11 is restarted in a state where there is a high possibility that abnormal spark will occur. Since starting is limited, the commutator motor 11 can be prevented from being burned out and the internal parts such as the stator of the commutator motor 11 can be prevented from being worn as much as possible to extend the life.

The external view of the vacuum cleaner which concerns on embodiment of this invention. The circuit diagram of the motor drive circuit to which the commutator motor provided in the vacuum cleaner which concerns on embodiment of this invention was connected. The figure which shows an example of the measurement result of the electric current value when changing the load of the commutator motor in the vacuum cleaner which concerns on embodiment of this invention, and its change width. The figure which shows an example of the measurement result of the electric current value when the abnormal spark of the commutator motor in the vacuum cleaner which concerns on embodiment of this invention generate | occur | produced, and its change width. The flowchart which shows an example of the procedure of the abnormal spark prevention process performed in the vacuum cleaner which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vacuum cleaner main body part 2 ... Intake port part 3 ... Connection pipe 4 ... Connection hose 5 ... Operation handle 11 ... Commutator motor (an example of a commutator motor)
12 ... Triac 13 ... Current fuse 14 ... Current transformer (an example of a transformer)
DESCRIPTION OF SYMBOLS 15 ... Voltage detection circuit 16 ... Control circuit S1, S2, ..., Processing procedure (step) number X ... Vacuum cleaner Y ... Motor drive circuit

Claims (6)

A vacuum cleaner that sucks dust by supplying power to a commutator motor having a stator and a commutator rotating in sliding contact with the stator and rotating a blower fan connected to the commutator motor,
Current change width detecting means for detecting a difference value between a maximum current value and a minimum current value at each predetermined time as a change width at a predetermined time of the current on the electric circuit to which the commutator motor is connected;
It is determined whether the variation range of the detected current for each I Ri said predetermined time in said current variation width detection means reaches or exceeds a preset upper threshold, the variation width by the current variation width detection device The commutator motor is stopped on condition that the number of times that the change width has reached the upper limit threshold or more among the predetermined number of times detected in the past is equal to or more than the number of abnormalities less than the predetermined number of times set in advance. Abnormality handling means for limiting the current applied to the commutator motor;
The vacuum cleaner characterized by comprising.   The electric vacuum cleaner according to claim 1, wherein the upper limit threshold is set in advance to detect that an abnormal spark is generated in the commutator motor.   Based on the output voltage value after the current change width detecting means is transformed by a transformer connected in series to the commutator motor, the current change width detection means at predetermined time intervals on the electric circuit to which the commutator motor is connected. The electric vacuum cleaner according to claim 1 or 2, which detects a change width. The commutator motor is operated by feeding AC power from a predetermined power source,
The current change width detecting means detects an effective current value for each cycle of AC power supplied from the predetermined power source to the commutator motor, and the effective current values of a plurality of cycles detected at the predetermined time are detected. The vacuum cleaner according to any one of claims 1 to 3, wherein a difference current value between a maximum value and a minimum value is detected as a change width of the current.   Informing the user of the electric vacuum cleaner that an abnormal spark has occurred in the commutator motor in response to the change width of the current detected by the current change width detecting means reaching the upper limit threshold or more. The vacuum cleaner according to any one of claims 2 to 4, further comprising an abnormal spark generation notifying means.   A restart limiting means for limiting restart of the commutator motor until the specific operation set in advance is performed after the commutator motor is stopped by the abnormality handling means. The vacuum cleaner in any one of 1-5.

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