Electric dust collector

Abstract

The invention provides an electric dust collector capable of stabilizing control of a motor and properly preventing overheating of the motor. The electric dust collector is provided with an electric blower, a motor (12) for collecting dust of a part (F) to be subjected to dust collection, and a control mechanism for controlling the motor (12). The control means reduces the drive power of the motor (12) on the basis of a predetermined lock determination condition, and makes it difficult to generate the reduction process at the initial start-up stage of the motor (12).

Description

Technical Field

[0001] An embodiment of the present invention relates to an electric vacuum cleaner that controls a motor for vacuuming a vacuumed portion. Background Art

[0002] Conventionally, as a cleaning tool used in an electric vacuum cleaner, there is known a suction port body having a so-called active brush structure, which includes a rotating cleaning body and a motor for rotating the rotating cleaning body. In this suction port body, the rotating cleaning body rotated by the motor temporarily scrapes dust from the surface to be cleaned and then sucks it in, thereby efficiently removing dust from a surface to be cleaned that is easily entangled with dust, such as a carpet.

[0003] The suction port body is configured such that when the rotary cleaning body is placed on a dusted surface with a large rotational resistance such as a carpet with a long hair length, or when a cloth or the like is involved in the rotary cleaning body, the motor is locked and a large current flows. Therefore, when the current value of the motor is monitored and the current value exceeds the threshold value of the specified current value for a specified time, it is determined that the motor is locked and the drive of the motor is stopped. In this configuration, the following configuration is known: a plurality of groups of time thresholds and current value thresholds for determination are set, one group is set to a group with a longer time threshold and a smaller current threshold, and the other group is set to a group with a shorter time threshold and a larger current threshold, and based on these conditions, the state of the suction port body, the rotary cleaning body or the motor is detected, thereby determining whether there is a dust collection action on the dusted surface and whether the motor is locked under normal conditions. However, in low temperature environments such as winter and the initial start-up, the current value of the motor becomes relatively large, so the determination accuracy of the motor lock based on the lock determination condition consisting of the group of time thresholds and current value thresholds may be reduced.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-68680 Summary of the invention

[0005] An object of the present invention is to provide an electric vacuum cleaner capable of stabilizing the control of a motor and appropriately preventing overheating of the motor.

[0006] The electric vacuum cleaner of the embodiment includes an electric blower, a motor for cleaning a cleaning area, and a control mechanism for controlling the motor. The control mechanism reduces the driving power of the motor based on a predetermined lock determination condition, and makes the reduction difficult to occur at the initial start of the motor.

[0007] Effect of the invention: According to the electric vacuum cleaner of the present invention, the driving power of the motor will not be reduced unnecessarily, and the reduction process can be implemented when necessary while stabilizing the control of the motor, and the excessive current caused by locking can be appropriately prevented from overheating the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 This is a cross-sectional view schematically showing a part of an electric vacuum cleaner according to an embodiment.

[0009] Figure 2 It is a block diagram showing a part of the internal structure of the electric vacuum cleaner as above.

[0010] Figure 3 It is a three-dimensional diagram showing the same electric vacuum cleaner.

[0011] Figure 4 : is a table showing an example of the lock determination condition of the electric vacuum cleaner as above.

[0012] Figure 5 (a) is a graph showing an example of the average value of the current value when the power-on time or the power supply amount of the motor of the same electric vacuum cleaner is small when the weight of the cleaning tool is applied, and (b) is a graph showing an example of the average value of the current value when the power-on time or the power supply amount of the motor of the same electric vacuum cleaner is large when the weight of the cleaning tool is applied.

[0013] Figure 6 This is a flowchart showing an example of processing that makes it difficult for the reduction processing in the control mechanism of the above electric vacuum cleaner to occur.

[0014] Description of Reference Numerals

[0015] CL electric vacuum cleaner

[0016] F The dust collected

[0017] 3 Electric blower

[0018] 12 Motor

[0019] 13 Control Agency DETAILED DESCRIPTION

[0020] Hereinafter, one embodiment will be described with reference to the drawings.

[0021] exist Figure 1 In the figure, 1 is a cleaning tool. The cleaning tool 1 is also called a dust head, etc., and cleans the dusted surface, i.e., the dusted part F, such as a floor. The cleaning tool 1 includes a housing 10. A dust collecting port 100 is formed on the housing 10. In addition, a rotating cleaning body 11 is rotatably arranged on the housing 10. The rotating cleaning body 11 is rotated by a motor 12 to scrape the dust from the dusted part F toward the dust collecting port 100. In this embodiment, the rotating cleaning body 11 is mounted on the dust collecting port 100. The motor 12 is driven by a motor 12. Figure 2 The control mechanism 13 shown controls.

[0022] like Figure 3As shown, the cleaning tool 1 is used for an electric vacuum cleaner CL. In the present embodiment, the cleaning tool 1 is applied to the following suction-type electric vacuum cleaner CL: dust and air are sucked into the separation part 4 together with the negative pressure generated by driving the suction source, that is, the electric blower 3, which is arranged on the vacuum cleaner body 2 of the electric vacuum cleaner CL. The electric vacuum cleaner CL can be any vacuum cleaner such as a floor-moving type or a horizontal type, a pole type, a vertical type, a handheld type, or a self-propelled electric vacuum cleaner. In the present embodiment, the electric vacuum cleaner CL is described by taking a pole-type electric vacuum cleaner as an example. In addition, in the illustrated example, the cleaning tool 1 is called a suction port body or a floor brush, and is indirectly or directly connected to the vacuum cleaner body 2 mechanically and fluidically via an extension tube 5 as a tube portion and a connecting tube 14 as a connecting portion connected to the shell 10. Moreover, in the present embodiment, the operation or suction force of the electric blower 3, or the operation intensity, i.e., the operation mode, such as the strong mode or the weak mode, and the on and off of the rotation of the rotary cleaning body 11 or the motor 12 are set by the user by operating the switch 7 of the manual operation unit 6, which is a gripping part for operation. The main body control unit 8 for operating the electric blower 3 according to the operation set by the switch 7 is arranged on the vacuum cleaner main body 2. The switch 7 or the main body control unit 8 and the control mechanism 13 ( Figure 2 Control mechanism 13 ( Figure 2 ) can also be configured on the cleaning tool 1, but in this embodiment, the control mechanism 13 ( Figure 2 At least a part of the power supply unit (as shown) is assembled in the main body control unit 8. The power supply unit B of the electric vacuum cleaner CL is, for example, arranged in the vacuum cleaner body 2. In the present embodiment, the power supply unit B is set as a battery or a secondary battery, but it is not limited thereto, and it can also be an AC-DC adapter, a cord winding device, etc. that obtains power from an external power source such as a commercial power supply.

[0023] Next, refer to Figure 1 as well as Figure 2 The internal structure of the control mechanism 13 will be described.

[0024] The control mechanism 13 has a power variable unit 130 that makes the driving power of the motor 12 variable. The power variable unit 130 can make the driving power of the motor 12 steplessly variable or change it to one of a plurality of stages. In the present embodiment, the power variable unit 130 can set the driving power of the motor 12 to at least one of a plurality of stages.

[0025] As a method for the power variable unit 130 to make the driving power of the motor 12 variable, for example, the power supply time or the amount of power supply from the power supply to the motor 12 is adjusted, and the driving power of the motor 12 is set according to the power supply time of the motor 12. As an example, the power variable unit 130 sets the control signal, i.e., the applied voltage to the motor 12, as a PWM signal, and sets the driving power of the motor 12 by adjusting the duty cycle of the PWM signal. That is, when the duty cycle of the PWM signal is set to 100%, the driving power of the motor 12 becomes maximum, and the driving power of the motor 12 is reduced by reducing the duty cycle of the PWM signal, and the rotation speed and rotation torque of the rotating cleaning body 11 are reduced. That is, the power variable unit 130 increases the duty cycle when increasing the driving power of the motor 12, and reduces the duty cycle when reducing the driving power of the motor 12. In the present embodiment, the power variable unit 130 has a plurality of different duty ratios, and the driving power of the motor 12 can be set to a plurality of different driving powers by selectively setting the duty ratio of the PWM signal of the motor 12 to any one of these duty ratios.

[0026] The power variable unit 130 can set the driving power of the motor 12 according to the user's setting of the switch 7 ( Figure 3 The power variable unit 130 can be switched according to the settings of the electric blower 3, such as the strength of the suction force of the electric blower 3 or the operation mode, or can be switched automatically according to the dust collection condition. The dust collection condition refers to, for example, the type of floor constituting the dust collection part F, or the amount of dust collected by the dust collection part F. That is, a dust collection condition detection mechanism such as a type detection mechanism for detecting the type of the dust collection part F and / or a dust amount detection mechanism for detecting the amount of dust collected can be combined, and the power variable unit 130 automatically selects and sets the driving power of the motor 12. The type detection mechanism and the dust amount detection mechanism can be any known structure. In the present embodiment, for example, the power variable unit 130 selectively uses a PWM signal with a duty cycle of 100% and a PWM signal with a duty cycle of 40%, and sets the driving power of the motor 12 to one of the strong and weak sides.

[0027] In addition, the control mechanism 13 has a current detection unit 131 for detecting the current value of the motor 12. The current detection unit 131 detects the current value of the motor 12 according to a specified detection cycle. As a detection method of the current value of the motor 12 by the current detection unit 131, as an example, a current flows in a resistor with a relatively small resistance value as a detection element, a so-called shunt resistor, and the potential difference generated at both ends of the shunt resistor is amplified and input into an A / D converter as a conversion unit, and the output of the A / D converter is obtained. In this embodiment, the current value detected by the current detection unit 131 is, for example, a load current value. The load current value is a current value indicating the load state of the rotating cleaning body 11 rotated by the motor 12, and is correlated with the actual current value of the motor 12. The actual current value of the motor 12 is, for example, an average value of the current value obtained a specified number of times at intervals of a specified time. The actual current value is largely dependent on the duty cycle of the PWM signal of the power variable unit 130. Therefore, in the present embodiment, the load current value is obtained as a value obtained by dividing the duty cycle of the PWM signal in the power variable unit 130 by the actual current value in order to be independent of the duty cycle of the PWM signal. That is, (load current value) = (actual current value) / (duty cycle). Therefore, the load current value of the present embodiment is a value calculated based on the current value flowing in the motor 12 and the duty cycle.

[0028] In the control and determination by the control mechanism 13, a value related to the current value detected by the current detection unit 131 may be used instead of the current value detected by the current detection unit 131 or in addition to the current value. The value related to the current value includes the current value itself flowing in the motor 12, a value obtained by subtracting a predetermined value from the current value flowing in the motor 12, and a value having a correlation with the current value calculated from the current value flowing in the motor 12. Hereinafter, "the current value of the motor 12 or a value related to the current value" is referred to as "the current value of the motor 12", and "the rotation load of the rotating cleaning body 11 or the motor 12" is referred to as "the rotation load".

[0029] In addition, in the present embodiment, the current detection unit 131 is described as including a current value acquisition unit having a detection element and an A / D converter, etc. to acquire the current value flowing in the motor 12, an actual current value calculation unit to obtain the actual current value, and a load current value calculation unit to obtain the load current value. However, the current value acquisition unit, the actual current value calculation unit, and the load current value calculation unit may be configured as separate circuit units, or they may be configured in any combination, and a part of them may become a part of another circuit unit. That is, the current detection unit 131 is not limited to a configuration that integrally includes a current value acquisition unit, an actual current value calculation unit, and a load current value calculation unit.

[0030] Furthermore, the control mechanism 13 has a storage unit 132 such as a memory. In the present embodiment, the current value detected by the current detection unit 131, various threshold values ​​for determination, determination values, etc. are stored in the storage unit 132. In addition, the storage unit 132 stores various data used in the control performed by the control mechanism 13, such as other arbitrary threshold values, flags, and programs.

[0031] In addition, the control mechanism 13 has a determination unit 133. The determination unit 133 determines the state of the motor 12 or the rotating cleaning body 11 based on the current value detected by the current detection unit 131, and controls the setting of the driving power of the motor 12 by the power variable unit 130 according to the determination. In the present embodiment, the determination unit 133 determines whether the rotating cleaning body 11 and the motor 12 are locked, that is, whether they are forced to stop rotating even when the motor 12 is powered on due to external important factors such as the involvement of cloth, etc., based on the preset locking determination conditions. The details of this determination will be described later.

[0032] In addition, the power supply of the motor 12 and the control mechanism 13 can be provided on the cleaning tool 1, or can be taken from the power supply unit B ( Figure 3 shown).

[0033] Next, the operation of one embodiment will be described.

[0034] When vacuuming, the user holds the manual operation unit 6 and operates the switch 7, thereby the main control unit 8 activates the electric blower 3. The negative pressure generated by the operation of the electric blower 3 acts on the extension tube 5 and the cleaning tool 1 through the separation unit 4, thereby sucking the dust in the vacuumed part into the separation unit 4 together with the air from the dust collection port 100.

[0035] In addition, the control mechanism 13 starts the motor 12 of the cleaning tool 1 through the power variable unit 130 to rotate the rotary cleaning body 11. The dust in the dust collection part F is scraped by the rotation of the rotary cleaning body 11, and the scraped dust is sucked into the separation part 4 by the negative pressure acting on the dust collection port 100. At this time, the control mechanism 13 uses, for example, a PWM signal corresponding to the operation mode of the electric blower 3 and the driving force set by the user to operate the motor 12. In addition, the user can operate the switch 7 to stop the rotation of the rotary cleaning body 11 of the cleaning tool 1 according to the need to prevent the rotary cleaning body 11 from being caught in an object, etc.

[0036] The user moves the cleaning tool 1 alternately forward and backward while being placed on the dust collection part F through the manual operation part 6, thereby sucking the dust on the dust collection part F into the separation part 4 in sequence. The dust-containing air sucked into the separation part 4 is separated and captured in the separation part 4. The air from which the dust is separated is discharged to the outside of the vacuum cleaner body 2 after cooling the electric blower 3.

[0037] The control mechanism 13 is such that, during the operation of the motor 12, the locking of the rotating cleaning body 11 and the motor 12 is determined in the determination unit 133 based on a comparison between a specified current value of the motor 12 detected by the current detection unit 131 and a threshold value of the current value in the locking determination condition, and a comparison between the continuation time and the time threshold.

[0038] In the present embodiment, "the prescribed current value of the motor 12" refers to the most recent current value within a prescribed short time from the time of determination, and preferably the latest current value is used, but it is not limited to this. It may be the current value immediately before the latest current value, that is, the latest current value among the current values ​​stored in the storage unit 132, that is, the current value before one detection cycle of the current value of the motor 12 by the current detection unit 131 from the time of determination. In addition, the immediately previous current value refers to the past current value closest to the prescribed current value among the current values ​​stored in the storage unit 132, that is, the current value before one detection cycle from the prescribed current value, but it is not limited to this. It may be the past current value within a prescribed time that is sufficiently short, such as two detection cycles or three detection cycles before the prescribed current value, or it may be the value calculated from a plurality of immediately previous current values, such as the average value of the current values ​​within a prescribed time from the prescribed current value.

[0039] Then, when the determination unit 133 determines that a predetermined lock determination condition is satisfied during the operation of the motor 12, the control mechanism 13 reduces the driving power of the motor 12 through the power variable unit 130 to substantially stop the motor 12. This control is hereinafter referred to as a reduction process or power reduction control.

[0040] The reduction process is a control for stopping the motor 12 to prevent the motor 12 from overheating due to the continuation of the locked state. The lock determination condition for implementing the reduction process can be set arbitrarily, but in the present embodiment, the condition includes at least a combination of a threshold value of the current value of the motor 12 and a time threshold. Then, the reduction process is implemented based on the state that the current value of the motor 12 is above the threshold value for a period of time exceeding the threshold value.

[0041] Here, the motor 12 has the following tendency: the power consumption for the load increases when in a low temperature environment, and decreases when in a high temperature environment. The low temperature environment refers to, for example, when used in winter or cold areas, when the internal temperature of the motor 12 drops below a predetermined temperature at the time of startup, and the high temperature environment refers to an environment that is the opposite, or an environment that is not a low temperature environment, that is, a non-low temperature environment.

[0042] Therefore, in the case where there is only one lock determination condition, for example, when vacuuming a carpet with a long hair length in a low temperature environment, that is, in a vacuuming environment where the current value of the motor 12 is likely to increase, when the threshold value of the current value in the lock determination condition is set relatively high in a manner that does not generate a reduction process, the current value of the motor 12 when the rotating cleaning body 11 and the motor 12 are locked in a high temperature environment becomes lower than the threshold value of the current value in the lock determination condition, and the reduction process may not be generated even in a necessary situation. On the contrary, for example, when the threshold value of the current value in the lock determination condition is set relatively low in a manner that generates a reduction process when the rotating cleaning body 11 and the motor 12 are locked in a high temperature environment, when vacuuming a carpet with a long hair length in a low temperature environment, the current value of the motor 12 will frequently exceed the threshold value of the current value in the lock determination condition, and the driving power of the motor 12 may be unnecessarily reduced, causing inconvenience to the user.

[0043] Therefore, in the present embodiment, a plurality of types of lock determination conditions are preset. The plurality of lock determination conditions are set such that the larger the current value threshold is, the smaller the time threshold is. That is, when any two of the plurality of lock determination conditions are compared, the magnitude relationship of the current value threshold and the magnitude relationship of the time threshold are reversed. That is, the current value threshold of other lock determination conditions is set smaller relative to the current value threshold of one lock determination condition, and the time threshold of other lock determination conditions is set larger relative to the time threshold of one lock determination condition.

[0044] Figure 4 An example of the lock determination condition of the present embodiment is shown. In the present embodiment, three types of lock determination conditions are preset. Lock determination condition 1 is, for example, a high current and short time condition with a current value threshold of 3A and a time threshold of 0.8 seconds. In addition, lock determination condition 2 is, for example, a low current and long time condition with a current value threshold of 2.25A and a time threshold of 1.6 seconds. Furthermore, lock determination condition 3 is, for example, an ultra-low current and ultra-long time condition with a current value threshold of 1.5A and a time threshold of 16 seconds.

[0045] In the lock determination condition 2, the time threshold of 1.6 seconds takes into account the time it takes for the user to move the cleaning tool 1 back and forth once. That is, the moving speed of the cleaning tool 1 by a general user is 0.5 m / sec as specified by the standards such as JIS, and the time it takes for a general user to move the cleaning tool 1 forward until it stops is about 0.8 to 1 second, and the time it takes for a general user to move the cleaning tool 1 backward until it stops or moves forward again is about 1 to 1.5 seconds, so the time required for the cleaning tool 1 to move back and forth once is set to 1.6 seconds.

[0046] When the dust collector 1 is pulled backward, a force is applied in the direction of lifting the cleaning tool 1 from the dust collection portion F, so the load on the rotating cleaning body 11 is greatly reduced, and the current value is reduced. Therefore, if the reduced current value is less than 2.25A or less than 1.5A, it is inconsistent with the locking judgment conditions 2 and 3, so if the cleaning tool 1 is moved forward and backward, only the locking judgment condition 1 becomes effective.

[0047] On the other hand, when the rotating cleaning body 11 and the motor 12 are locked, the current value of the motor 12 is relatively constant, so the locking judgment conditions 2 and 3 also become valid. Even if it is assumed that the current value is low when the rotating cleaning body 11 and the motor 12 are locked, a locking judgment is generated, that is, a judgment that the rotating cleaning body 11 and the motor 12 are locked is generated.

[0048] In this way, by setting a plurality of locking judgment conditions having a combination of a current value threshold and a time threshold as conditions, and reversing the magnitude relationship of the current value threshold and the magnitude relationship of the time threshold in these locking judgment conditions, it is possible to distinguish between the situation of vacuuming a carpet with a long hair length in a low temperature environment and the situation of locking the rotating cleaning body 11 and the motor 12 in a high temperature environment, and reduce processing when necessary.

[0049] However, for example, in a low-temperature environment, when the cleaning tool 1 is stationary on a carpet with a long hair length, it can be considered that the current value of the motor 12 is relatively high for a long time. In particular, the cleaning tool 1 often stops on the dusted part F immediately after the start of vacuuming, so there is a concern that the lock determination condition will be met soon after the start and a reduction process will occur. In addition, when the control mechanism 13 reduces the driving power of the motor 12 by some control compared to usual, since the rotation torque of the rotating cleaning body 11 is small, the rotation resistance generated by the carpet and the like becomes a relatively large load, and the difference in current value on the carpet from when it is locked becomes smaller than usual. When the relative increase in the current value of the motor 12 in a low-temperature environment and the relative decrease in the current value of the motor 12 in a high-temperature environment are added to this, the following reverse state is likely to occur: the current value of the motor 12 when vacuuming the carpet in a low-temperature environment and the current value when the rotating cleaning body 11 and the motor 12 are locked in a high-temperature environment, the former becomes larger.

[0050] Therefore, in the present embodiment, the reduction process is made difficult to occur at the initial stage of starting the motor 12 .

[0051] The initial start-up period of the motor 12 refers to, for example, a period during which the accumulated drive time or a value related thereto from the start of the motor 12 is within a predetermined threshold value, i.e., a threshold value for determination. Then, if the accumulated drive time or a value related thereto from the start of the motor 12 is less than a predetermined threshold value for determination, a state in which it is difficult to generate a reduction process is set, and the accumulated drive time or a value related thereto from the start of the motor 12 becomes greater than a predetermined threshold value for determination as at least one condition, the state in which it is difficult to generate the reduction process is canceled and the state is returned to the original state.

[0052] For example, the time until the internal temperature of the motor 12 is assumed to exceed a predetermined temperature is set as the judgment threshold. It has been found through experiments that the internal temperature of the motor 12 gradually rises due to its own heat generated by continuous driving, and as the internal temperature rises, it escapes from the low temperature state in a relatively short time and the large change in the current value converges. Therefore, in this embodiment, for example, the time until it is expected to escape from its low temperature state is set as the judgment threshold, for example, 1 minute.

[0053] In addition, as the energization time or the amount of energization of the motor 12 increases, the current value flowing in the motor 12 increases, so there is a tendency that the heat generated by the motor 12 increases and the time until the motor 12 is released from the low temperature state becomes shorter. Figure 5 Compared with the case where the energization time or energization amount of the motor 12 is small, such as when the duty ratio of the PWM signal is 40%, Figure 5 When the power-on time or the amount of power supplied to the motor 12 is large, such as when the duty cycle of the PWM signal is 100%, as shown in example (b), the change in the current value of the motor 12 converges faster. Therefore, it is preferable to change the cumulative driving time or the degree of accumulation of its related values, or the judgment threshold value according to the power-on time or the amount of power supplied to the motor 12, such as the duty cycle of the PWM signal. The longer the power-on time or the amount of power supplied, the greater the change in the cumulative driving time or the degree of accumulation of its related values, or the shorter the change in the judgment threshold value.

[0054] As a process of "making the reduction process difficult to occur", various methods can be adopted. For example, a method such as adding a further condition to the lock determination condition of the determination unit 133, correcting the current value detected by the current detection unit 131, ignoring the lock determination, etc. can be adopted. However, in this embodiment, in the determination unit 133, the lock determination condition is changed or tightened to make it difficult for the lock determination to occur.

[0055] The lock determination condition can be changed or tightened by various methods. For example, 1) invalidating one or more of the pre-set multiple lock determination conditions starting from the condition with the lower current value threshold, 2) pre-setting the current value threshold and / or time threshold of the lock determination condition used in the initial startup to a value different from the lock determination condition used other than the initial startup, 3) calculating the current value threshold and / or time threshold of the lock determination condition used in the initial startup based on a certain pre-set defined value, etc. In particular, in the initial startup of the motor 12, considering that the current value of the motor 12 is relatively large, it is preferred to tighten the condition of the current value or its related value threshold in the lock determination condition. In the present embodiment, the above 1) is used, and in Figure 4 In the example shown, at least "lock determination condition 3" having the lowest threshold value of the current value is invalidated.

[0056] Also refer to Figure 6 The flowchart shown explains this control.

[0057] When the electric vacuum cleaner CL is started, in step S1, the control mechanism 13 sets the flag isCold indicating whether it is the initial start-up period, that is, whether it is a low temperature environment, to True, and sets the timer tCold indicating the cumulative driving time of the motor 12 from the start-up to 0. In the control mechanism 13, the lock determination condition is tightened in the determination unit 133 so that the reduction process is less likely to occur during the period when the flag isCold is True.

[0058] Next, in step S2, the control mechanism 13 determines whether the motor 12 is being driven, for example, based on the current value detected by the current detection unit 131. When it is determined that the motor 12 is not being driven, that is, in the case of "No" in step S2, step S2 is repeated. In addition, in step S2, when it is determined that the motor 12 is being driven, that is, in the case of "Yes" in step S2, in step S3, the control mechanism 13 determines whether the power-on time or the power-on amount of the motor 12, or in this embodiment, the duty cycle of the PWM signal, is greater than a predetermined threshold value D_Heat. The threshold value D_Heat is a duty cycle assuming that the motor 12 heats up faster, and is set to 50% in this embodiment, for example.

[0059] In step S3, if it is determined that the duty cycle is greater than D_Heat, that is, if the answer is "yes" in step S3, in step S4, the control unit 13 adds the accumulation level C_Hi to the timer tCold, and proceeds to step S5. The accumulation level C_Hi is the amount added to the timer tCold when the duty cycle is relatively large, and is set to 2, for example, in this embodiment.

[0060] In step S3 , when it is determined that the duty ratio is not equal to or greater than D_Heat, that is, when the answer is “NO” in step S3 , in step S6 , the control unit 13 increments the timer tCold by 1 and the process proceeds to step S5 .

[0061] Therefore, in the present embodiment, by the processing of steps S3, S4, and S6, when the duty ratio of the PWM signal for driving the motor 12 is 50% or more, the accumulation degree is doubled compared to the case where the duty ratio of the PWM signal for driving the motor 12 is less than 50%. In addition, in the present embodiment, the cycle period of the control of steps S2 to S6 is, for example, an example in which the detection cycle of the current value of the motor 12 by the current detection unit 131 is set to 100 ms. Therefore, when the duty ratio of the PWM signal for driving the motor 12 is less than 50%, the accumulation degree is 100 ms, and when the duty ratio of the PWM signal for driving the motor 12 is 50% or more, the accumulation degree is 200 ms.

[0062] Then, in step S5, the control mechanism 13 determines whether the timer tCold is greater than the determination threshold value T_Heat. The determination threshold value T_Heat is set to 600, for example. That is, in the case of the present embodiment, the determination threshold value T_Heat is equivalent to 6000 ms, i.e., 1 minute. In step S5, when it is determined that the timer tCold is not greater than the determination threshold value T_Heat, that is, in the case of "No" in step S5, the process proceeds to step S2. In addition, in step S5, when it is determined that the timer tCold is greater than the determination threshold value T_Heat, that is, in the case of "Yes" in step S5, in step S7, the control mechanism 13 sets the flag isCold to False, that is, it is determined that it is no longer the initial start-up of the motor 12, or it has left the low temperature environment, and ends the process.

[0063] Thus, according to the present embodiment, the control mechanism 13 performs a reduction process on the driving power of the motor 12 based on the prescribed locking judgment condition, making it difficult for the reduction process to occur in the initial stage of starting the motor 12, thereby suppressing the frequent occurrence of the reduction process based on the locking judgment condition due to the increase in the current value of the motor 12 in the low temperature environment in the initial stage of starting.

[0064] Therefore, for example, even when starting the motor 12 in winter or in cold areas, when the temperature is low and the current value of the motor 12 becomes large, the reduction processing of the motor 12 by the control mechanism 13 can be generated with high accuracy and appropriately, so that the driving power of the motor 12 is not reduced unnecessarily, and the reduction processing can be implemented when necessary while stabilizing the control of the motor 12, and the motor 12 can be appropriately prevented from overheating due to excessive current caused by locking.

[0065] For example, by setting a plurality of locking judgment conditions having at least a combination of a threshold value of the current value of the motor 12 or a related value thereof and a time threshold as conditions, and by invalidating one or more locking judgment conditions in the order of the threshold value of the current value of the motor 12 or a related value thereof from small to large, it is made difficult for reduction processing to occur, thereby making it easy to suppress the reduction processing caused by the locking judgment conditions caused by the increase in the current value of the motor 12 in a low temperature environment at the initial stage of startup.

[0066] In addition, in a low temperature environment at the initial start-up of the motor 12, one or more lock determination conditions are invalidated in the order of the thresholds of the current value or its related value of the motor 12 from small to large, so that, for example, a lock determination condition can be set in which the threshold of the current value or its related value and / or the time threshold is set to a more extreme value. Figure 4 In the example shown, even if the lock determination condition 3 is set to make the threshold of the current value or its related value extremely small and the time threshold extremely long, it is basically invalidated at the initial stage of starting the motor 12, and it is possible to prevent unnecessary lock determinations due to the lock determination condition. Therefore, when the motor 12 has left the low temperature environment after the initial stage of starting, it is possible to further use the lock determination condition in which the threshold of the current value or its related value and / or the time threshold are set to more extreme values, and appropriately perform the lock determination when the motor 12 is locked.

[0067] Moreover, by using the situation that the accumulated driving time of the motor 12 since the start of the motor 12 or its related value becomes above the prescribed judgment threshold as at least one condition, the processing that makes it difficult to make a locking judgment is canceled, thereby preventing the state in which the current value is stabilized, the processing is reduced, or the locking judgment is difficult to make from continuing even if the motor 12 leaves the low temperature environment.

[0068] In addition, the accumulated driving time or its related value, or the judgment threshold is changed according to the power-on time or the power supply amount of the motor 12, which is the duty cycle of the PWM signal in this embodiment. This makes it possible to consider the influence of the heat associated with the power-on of the motor 12 and appropriately set the period in which the reduction processing or locking judgment is difficult to occur.

[0069] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope and purpose of the invention, and are included in the invention described in the scope of the patent claim and its equivalent scope.

Claims

1. An electric vacuum cleaner, characterized in that: have: Electric blower; A motor for vacuuming the vacuumed part; as well as a control mechanism for controlling the motor, The control means performs a process of reducing the driving power of the motor based on a predetermined lock determination condition, and makes the process of reducing the power hardly occur at an initial stage of starting the motor.

2. The electric vacuum cleaner according to claim 1, characterized in that The process of making it difficult to perform the reduction process is canceled under at least one of the conditions that the cumulative driving time of the motor from the start of the motor or a value related thereto becomes equal to or larger than a predetermined threshold value.

3. The electric vacuum cleaner according to claim 2, characterized in that: The cumulative driving time or the degree of accumulation of a value related thereto, or the threshold value is changed according to the energization time or the energization amount of the motor.

4. The electric vacuum cleaner according to any one of claims 1 to 3, characterized in that: The lock determination condition is set to be a plurality of conditions, each of which has at least a combination of a threshold value of the motor current value or a value related thereto and a time threshold value as a condition. The threshold values ​​of the motor current value or its related value are arranged in ascending order, so that one or more of the lock determination conditions are invalidated, thereby making it difficult for the reduction process to occur.

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