vacuum cleaner

Abstract

To provide a vacuum cleaner capable of saving power.SOLUTION: A vacuum cleaner includes: a motor 12; a rotary cleaning body 11 to be rotated by the motor 12; and control means for controlling the motor 12. The control means reduces drive power of the motor 12 when a first condition is satisfied, where a calculation value based on at least a predetermined load current value of the motor 12 and a preceding load current value is equal to or greater than a first threshold and is equal to or smaller than a second threshold, which are smaller than the load current value, over predetermined first time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] An embodiment of the present invention relates to an electric vacuum cleaner having a rotating cleaning body that is rotated by a motor. [Background technology]

[0002] A known cleaning tool for use in a vacuum cleaner is a suction inlet body with a so-called active brush structure, which includes a rotating cleaning body and a motor that rotates the rotating cleaning body. In this type of suction inlet body, the rotating cleaning body rotates by the power of the motor, first scraping up dust from the surface to be cleaned and then sucking it up, thereby efficiently removing dust from surfaces where dust tends to become entangled, such as carpets.

[0003] In consideration of safety and energy saving, it is preferable that the rotation of the rotating cleaning element be suppressed or stopped when the rotating cleaning element of the suction port body is separated from the surface to be cleaned. Therefore, there is known a device that reduces the driving power of the motor when a comparison value based on the current consumption of the motor continues to fall below a predetermined threshold value for a predetermined time while the motor is running.

[0004] When determining whether the rotary cleaning body is attached to or detached from the surface to be cleaned based on the motor current value, it is necessary to reduce the time required for the determination to save power. Also, because the motor current value fluctuates due to various factors, it is necessary to detect the attachment or detachment of the rotary cleaning body to or detached from the surface to be cleaned with high accuracy. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-68680 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a vacuum cleaner that is capable of saving power. [Means for solving the problem]

[0007] In one embodiment, the electric vacuum cleaner includes a motor, a rotary cleaning element rotated by the motor, and a control unit that controls the motor, and the control unit reduces the drive power of the motor when a first condition is satisfied, where a calculated value based on at least a predetermined load current value of the motor and the load current value immediately before the predetermined load current value is equal to or greater than a first threshold value and is equal to or less than a second threshold value that is smaller than the load current value for a first predetermined time period. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view schematically showing a part of a vacuum cleaner according to a first embodiment. [Figure 2] FIG. 2 is a block diagram showing a part of the internal structure of the electric vacuum cleaner. [Figure 3] FIG. [Figure 4] 4 is a graph showing an example of a change over time in a load current value of the motor. [Figure 5] 4 is a flowchart showing control by the control means. [Figure 6] 10 is a graph showing another example of a change over time in the load current value of the motor. [Figure 7] 4A and 4B are explanatory diagrams showing the driving state of the motor of the cleaning tool. [Figure 8] FIG. 4 is a cross-sectional view schematically showing a part of a vacuum cleaner according to a second embodiment. [Figure 9] 4 is a graph showing an example of a change over time in a load current value of the motor. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) The first embodiment will be described below with reference to the drawings.

[0010] In FIG. 1, reference numeral 1 denotes a cleaning tool. The cleaning tool 1 is also called a cleaning head or the like and cleans a cleaning target area F, which is a surface to be cleaned, such as a floor. The cleaning tool 1 includes a case body 10. A dust collection port 100 is formed in the case body 10. A rotary cleaning body 11 is rotatably attached to the case body 10 facing the dust collection port 100. The rotary cleaning body 11 is rotated by a motor 12 to stir up dust on the cleaning target area F. The motor 12 is controlled by a control means 13 shown in FIG. 2. Note that hereinafter, the front-to-rear direction of the cleaning tool 1 shown in FIG. 1 is based on the direction as seen by a user when using the cleaning tool 1. Generally, the direction away from the user is referred to as the front direction, and the direction toward the user is referred to as the rear direction. For example, the direction of arrow FR in FIG. 1 is referred to as the front direction, and the direction of arrow RR is referred to as the rear direction.

[0011] As shown in FIG. 3 , the cleaning tool 1 is used in a vacuum cleaner CL. In this embodiment, the cleaning tool 1 is a suction-type vacuum cleaner CL that sucks dust and air into a separation unit 4 by using negative pressure generated by driving a suction source 3, such as an electric blower, disposed in the vacuum cleaner body 2 of the vacuum cleaner CL. The vacuum cleaner CL may be any type, such as a floor-traveling type, a canister type, a stick type, an upright type, a handheld type, or a self-propelled vacuum cleaner. In this embodiment, the vacuum cleaner CL is described using a stick-type vacuum cleaner as an example. In the illustrated example, the cleaning tool 1 is also called a suction port body or floor brush, and is mechanically and fluidly connected to the vacuum cleaner body 2 via an extension tube 5, which is a tubular part, or a connection tube 14, which is a connector connected to the case body 10. Furthermore, in this embodiment, the operation or suction force of the suction source 3 and the on / off of the rotation of the rotary cleaning body 11 or the motor 12 are set by the user by operating a switch 7 on a handheld operation unit 6. A main body control unit 8 is disposed in the vacuum cleaner main body 2, and operates the suction source 3 in response to an operation set by the switch 7. The switch 7 or the main body control unit 8 is electrically connected to control means 13. The control means 13 may be disposed in the cleaning tool 1, but in this embodiment, at least a part of the control means 13 is incorporated in the main body control unit 8. A power supply unit B of the electric vacuum cleaner CL is disposed in, for example, the vacuum cleaner main body 2. In this embodiment, the power supply unit B is a battery or a secondary battery, but is not limited to this, and may also be a cord reel device that draws power from an external power source such as a commercial power source.

[0012] Next, the internal structure of the control means 13 will be described with reference to FIGS.

[0013] The control means 13 has a power variable unit 130 that varies the drive power of the motor 12. The power variable unit 130 may vary the drive power of the motor 12 continuously or may vary it in one of a plurality of steps. In this embodiment, the power variable unit 130 is capable of setting the drive power of the motor 12 to at least one of a plurality of steps.

[0014] The power variable unit 130 varies the drive power of the motor 12, for example, by adjusting the duration or amount of current flow from the power source to the motor 12, thereby setting the drive power of the motor 12 according to the duration of current flow to the motor 12. As an example, the power variable unit 130 sets the drive power of the motor 12 by using a PWM signal as the control signal, i.e., the applied voltage, to the motor 12 and adjusting the duty ratio of the PWM signal. That is, when the duty ratio of the PWM signal is set to 100%, the drive power of the motor 12 is maximized, and by lowering the duty ratio of the PWM signal, the drive power of the motor 12 is reduced, thereby reducing the rotational speed and rotational torque of the rotary cleaning body 11. That is, when the drive power of the motor 12 is increased, the power variable unit 130 increases the duty ratio, and when the drive power of the motor 12 is reduced, the power variable unit 130 decreases the duty ratio. In this embodiment, the power variable unit 130 has a plurality of different duty ratios, and by selectively setting the duty ratio of the PWM signal of the motor 12 to one of these duty ratios, the drive power of the motor 12 can be set to a plurality of different drive powers.

[0015] The control means 13 or the power variable unit 130 may control the motor 12 to rotate the rotary cleaning body 11 in any direction. For example, the control means 13 or the power variable unit 130 may control the motor 12 so that the rotation direction of the rotary cleaning body 11 is fixed in one direction regardless of the traveling direction of the cleaning tool 1, or may control the motor 12 so that the rotation direction of the rotary cleaning body 11 changes depending on the traveling direction of the cleaning tool 1. In this embodiment, the control means 13 or the power variable unit 130 controls the rotation direction of the motor 12 so that the rotary cleaning body 11 rotates in a direction in which the part to be cleaned F faces from front to rear, i.e., the counterclockwise direction indicated by the arrow X in FIG. 1 . In other words, in this embodiment, the control means 13 or the power variable unit 130 controls the rotation direction of the motor 12 so that the rotary cleaning body 11 rubs against the part to be cleaned F from front to rear. In other words, the control means 13 or the power variable unit 130 keeps the rotation direction of the motor 12 constant. In this embodiment, the rotation direction of the rotating cleaning body 11 is forward rotation or normal rotation for the forward movement of the cleaning tool 1, that is, a direction that assists the forward movement of the cleaning tool 1, and is reverse rotation or inverse rotation for the backward movement of the cleaning tool 1, that is, a direction that imposes a greater load on the backward movement of the cleaning tool 1.

[0016] The control unit 13 also includes a current detection unit 131 that detects the load current value of the motor 12. The load current value of the motor 12 indicates the load state of the rotating cleaning body 11 rotated by the motor 12 and correlates with the actual current value of the motor 12. The actual current value of the motor 12 is, for example, the average of current values ​​acquired a predetermined number of times at a predetermined time interval. As an example, the actual current value is the average of M current values ​​acquired once every 1 / N seconds, where N and M are natural numbers. That is, the actual current value is the average of current values ​​acquired over an acquisition time period T=M / N seconds. Preferably, N is 2 or greater, and M is 1 or a true divisor of N, i.e., a divisor of N smaller than N. In this embodiment, N=1000 and M=100, and the actual current value is the average of current values ​​acquired over an acquisition time period T=0.1 seconds. This actual current value is highly dependent on the duty ratio of the PWM signal of the power variable unit 130. Therefore, in this embodiment, the load current value is calculated by dividing the actual current value by the duty ratio of the PWM signal in the power variable unit 130 to make it independent of the duty ratio of the PWM signal. That is, (load current value) = (actual current value) / (duty ratio). Therefore, the load current value in this embodiment is a value calculated from the value of the current flowing through the motor 12.

[0017] Furthermore, the load current value is not limited to a value calculated from the current value flowing through motor 12, but may be the current value flowing through motor 12 itself, or a value obtained by subtracting a predetermined value from the current value flowing through motor 12. This predetermined value is the load current value when the rotational load of rotary cleaning body 11 or motor 12 is constant or approximately constant, for example, half the load current value of motor 12 detected when rotary cleaning body 11 is allowed to run idly, particularly when rotary cleaning body 11 is allowed to run idly for confirmation during manufacturing of cleaning tool 1. In other words, hereinafter, the term "load current value" includes a value calculated from the current value flowing through motor 12 and correlating with this current value. Furthermore, the "rotational load of rotary cleaning body 11 or motor 12" will be simply referred to as the "rotational load."

[0018] As an example of a method for detecting the current value of the motor 12 by the current detection unit 131, a current is passed through a resistor with a small resistance value, which is a detection element, a so-called shunt resistor, and the potential difference generated across the shunt resistor is amplified and input to an A / D converter, which is a conversion unit, and the output of the A / D converter is taken in.

[0019] In the present embodiment, the current detection unit 131 has been described as including a current value acquisition unit that has a detection element, an A / D converter, etc. and acquires the value of a current flowing through the motor 12, an actual current value calculation unit that calculates an actual current value, and a load current value calculation unit that calculates a load current value, but the current value acquisition unit, actual current value calculation unit, and load current value calculation unit may each be configured as separate circuit units, or may be configured in any combination, or some of them may form part of other circuit units. In other words, the current detection unit 131 is not limited to being configured as an integrated unit that includes the current value acquisition unit, actual current value calculation unit, and load current value calculation unit.

[0020] The control means 13 further includes a storage unit 132 such as a memory. In this embodiment, the storage unit 132 stores and holds the load current value detected by the current detection unit 131 each time. The load current values ​​stored in the storage unit 132 may be updated each time a new load current value is detected, or may be held for a predetermined time and the oldest load current value deleted each time a new load current value is detected. The storage unit 132 also stores minimum and / or maximum load current values. The minimum and maximum values ​​may be held for a predetermined time and then deleted. The storage unit 132 also stores various thresholds and judgment values ​​for judgment. Note that, hereinafter, the minimum value is not limited to a single minimum value, but may also be a value sufficiently close to the minimum value, or one of multiple minimum values ​​or peak values ​​among the fluctuating load current values, or an average value of at least one of the minimum values ​​or peak values. Similarly, the maximum value is not limited to a single maximum value, but may be a value sufficiently close to the maximum value, or any of multiple maximum values ​​or peak values ​​among the fluctuating load current values, or the average value of at least any of those maximum values ​​or peak values.

[0021] The control means 13 also has a determination unit 133. The determination unit 133 determines the state of the cleaning tool 1 or the rotary cleaning body 11 based on the load current value detected by the current detection unit 131 and the past load current values ​​stored in the memory unit 132, and controls the setting of the drive power of the motor 12 by the power variable unit 130 in accordance with this determination. The determination made by the determination unit 133 will be described later.

[0022] The power source for the motor 12 and the control means 13 may be provided in the cleaning tool 1 or may be taken from the power source section B of the cleaner body 2.

[0023] Next, the operation of the first embodiment will be described.

[0024] When cleaning, the user grasps the hand-operated control unit 6 and operates the switch 7, which causes the main body control unit 8 to operate the suction source 3. The negative pressure generated by the operation of the suction source 3 acts on the extension tube 5 and the cleaning tool 1 via the separation unit 4, causing dust on the area to be cleaned to be sucked into the separation unit 4 along with the air from the dust collection port 100. The user uses the hand-operated control unit 6 to alternately move the cleaning tool 1 back and forth while it is placed on the area to be cleaned F, thereby sequentially sucking the dust on the area to be cleaned F into the separation unit 4. Dust is separated and collected from the dust-containing air sucked into the separation unit 4. The air from which the dust has been separated cools the suction source 3 and is then discharged outside the vacuum cleaner main body 2.

[0025] Furthermore, the control means 13 activates the motor 12 of the cleaning tool 1 using the power variable unit 130 to rotate the rotary cleaning body 11. The rotation of the rotary cleaning body 11 stirs up dust on the area to be cleaned F, and the stirred-up dust is sucked into the separating unit 4 by the negative pressure acting on the dust collection port 100. Note that the user can operate the switch 7 to stop the rotation of the rotary cleaning body 11 of the cleaning tool 1 as necessary, for example to prevent an object from being caught in the rotary cleaning body 11.

[0026] The control means 13 may arbitrarily set the drive power of the motor 12 when it is started. However, in this embodiment, for example, because it is unclear whether the cleaning tool 1 is in contact with the object to be cleaned F when the motor 12 is started, i.e., when the rotary cleaning body 11 is started, it is preferable for the control means 13 to start the motor 12 at a relatively low drive power using the power variable unit 130. This causes the rotary cleaning body 11 to rotate at a low speed. Then, when the determination unit 133 determines that a predetermined increase condition is met while the drive power of the motor 12 is relatively low, the control means 13 increases the drive power of the motor 12 using the power variable unit 130, causing the rotary cleaning body 11 to rotate at a high speed. This control is hereinafter referred to as power increase control. Furthermore, when the determination unit 133 determines that a predetermined decrease condition is met while the drive power of the motor 12 is relatively high, the control means 13 decreases the drive power of the motor 12 using the power variable unit 130, causing the rotary cleaning body 11 to rotate at a low speed or stop. This control will be referred to as power reduction control hereinafter.

[0027] The above-described power reduction control aims to reduce the rotation speed or rotation torque of the rotary cleaning body 11 by reducing the rotation speed of the motor 12 from a relatively high state. In this embodiment, the conditions for implementing the power reduction control are considered to be at least one of the following: (1) when the cleaning tool 1 or the rotary cleaning body 11 has lifted up or separated from the part to be cleaned F, or (2) when the part to be cleaned F that the cleaning tool 1 or the rotary cleaning body 11 is in contact with is a type of part with a small rotation load, such as a wooden floor. In this embodiment, these are determined by the determination unit 133 based on the load current value of the motor 12 detected by the current detection unit 131 of the control means 13.

[0028] In the above case (1), the load on the rotary cleaning body 11 is relatively small, and therefore the load current value of the motor 12 is relatively small. Therefore, in these cases, as shown in Fig. 4, it is assumed that the load current value I(t) is small, and the load current value I(t) or its fluctuations are small, will continue for a predetermined period of time or longer.

[0029] Therefore, the control unit 13 determines that the fluctuation of the load current value is small when the predetermined load current value of the motor 12 is substantially the same as or equal to the immediately preceding load current value. Specifically, when the determination unit 133 determines that the calculated value C based on the predetermined load current value of the motor 12 detected by the current detection unit 131 and the immediately preceding load current value stored in the memory unit 132 satisfies at least a first condition (that is, the calculated value C is equal to or greater than the first threshold value Th1 and equal to or less than the second threshold value Th2) over a first time period T1, the control unit 13 outputs a signal from the determination unit 133 to the power variable unit 130 to reduce the drive power of the motor 12 or to implement power reduction control to set the drive power to a relatively small value. That is, in this embodiment, the first condition is, for example, a detachment determination condition for determining whether the cleaning tool 1 or the rotating cleaning body 11 is detached from the cleaned part F. That is, the first condition in this embodiment is that the fluctuation of the load current value of the motor 12 is small over a predetermined first time period T1.

[0030] In this embodiment, the "predetermined load current value" refers to a load current value within a predetermined short time from the time of determination, i.e., the most recent load current value, and is preferably used, but is not limited to this. It may also be the load current value immediately before the latest load current value, i.e., the most recent load current value stored in the storage unit 132, i.e., the load current value obtained T seconds before the time of determination. Furthermore, the immediately previous load current value refers to the load current value stored in the storage unit 132 that is closest to the predetermined load current value, i.e., the load current value obtained T seconds before the predetermined load current value. However, it is not limited to this. It may also be a past load current value within a sufficiently short predetermined time, such as 2T seconds or 3T seconds before the predetermined load current value, or a value calculated from multiple immediately previous load current values, such as the average of load current values ​​within a predetermined time from the predetermined load current value.

[0031] Furthermore, the calculated value C based on a predetermined load current value and its immediately preceding load current value is, for example, the difference between the predetermined load current value and its immediately preceding load current value, and / or the ratio between the predetermined load current value and its immediately preceding load current value.

[0032] The first threshold value Th1 and the second threshold value Th2 are values ​​that are sufficiently smaller than the load current value, for example, on the order of about 1 / 10 of the load current value.

[0033] The first threshold value Th1 and the second threshold value Th2 are values ​​set based on fluctuations in the load current value when the rotation load is constant or approximately constant. The second threshold value Th2 is a value greater than the first threshold value Th1. When the calculated value C is the difference between a predetermined load current value and the load current value immediately preceding it, in this embodiment, the first threshold value Th1 is a negative value, such as −25 mA, and the second threshold value Th2 is a positive value, such as 25 mA. That is, in this example, the second threshold value Th2 has an absolute value equal to that of the first threshold value Th1. In this case, the determination unit 133 may directly compare the difference between the predetermined load current value and the load current value immediately preceding it with the first threshold value Th1 and the second threshold value Th2, respectively, or may compare the absolute value of the difference between the predetermined load current value and the load current value immediately preceding it with a first absolute value A1, which is the absolute value of the first threshold value Th1 and the second threshold value Th2. Furthermore, since it is considered that the load current value of the motor 12 will generally decrease due to heat generation when the rotary cleaning body 11 is rotating idly, the determination unit 133 may make a stricter determination for an increase in the load current value of the motor 12 than for a decrease. In this case, the second threshold value Th2 is set to a positive value smaller than the absolute value of the first threshold value Th1. In this case, the second threshold value Th2 is set to, for example, 15 mA.

[0034] Furthermore, when the calculated value C is the ratio between a predetermined load current value and the load current value immediately preceding it, in this embodiment, the first threshold value Th1 is less than 1, e.g., 0.97, and the second threshold value Th2 is greater than 1, e.g., 1 / 0.97. That is, in this example, the first threshold value Th1 and the second threshold value Th2 are reciprocals of each other and are positive values. In this case, the determination unit 133 may compare the ratio between the predetermined load current value and the load current value immediately preceding it with the first threshold value Th1 and the second threshold value Th2, respectively, or may compare the absolute value of the difference between the predetermined load current value and the load current value immediately preceding it with a value obtained by multiplying the predetermined load current value or the immediately preceding load current value by (1 - the first threshold value Th1). Furthermore, since it is considered that the load current value generally decreases due to heat generation from the motor 12 when the rotating cleaning body 11 is idling, the determination unit 133 may be more strict with respect to an increase in the load current value of the motor 12 than with respect to a decrease. In this case, the second threshold value Th2 is a positive value greater than the reciprocal of the first threshold value Th1. In this case, the second threshold value Th2 is set to, for example, 1.01.

[0035] Furthermore, noise may be introduced into the motor 12 from the suction source 3, and the accuracy of the A / D converter may be insufficient. In such cases, if the calculated value C is slightly smaller than the first threshold value Th1 or slightly larger than the second threshold value Th2, the determination of (1) above is postponed by the first time T1. Therefore, preferably, a margin or width is provided for the comparison of the calculated value C with the first threshold value Th1 and the second threshold value Th2 by the determination unit 133. That is, in this embodiment, the control unit 13 extends the first time T1 when the calculated value C is smaller than the first threshold value Th1 and larger than the third threshold value Th3, or larger than the second threshold value Th2 and smaller than the fourth threshold value Th4. That is, in this embodiment, the control unit 13 suspends the determination if the calculated value is within the range between the third threshold value Th3 and the fourth threshold value Th4, even if the first condition is not satisfied.

[0036] The third threshold Th3 and the fourth threshold Th4 are values ​​sufficiently smaller than the load current value, for example, on the order of about 1 / 10 of the load current value. The third threshold Th3 is smaller than the first threshold Th1, and the fourth threshold Th4 is larger than the second threshold Th2. In other words, when the calculated value C is slightly smaller than the first threshold Th1 or when the calculated value C is slightly larger than the second threshold Th2, the control means 13 temporarily suspends the determination by the determination unit 133, thereby effectively extending the first time T1. The length by which the first time T1 is extended is a predetermined unit time shorter than the first time T1. The unit time is, for example, a sufficiently short time that is correlated with the acquisition time T, and in this embodiment, is equal to the acquisition time T.

[0037] For example, if the calculated value C is the difference between a predetermined load current value and the immediately preceding load current value, the third threshold Th3 is a negative value, such as −50 mA, and the fourth threshold Th4 is a positive value, such as 50 mA. That is, in this example, the fourth threshold Th4 has the same absolute value as the third threshold Th3. In this case, the determination unit 133 may directly compare the difference between the predetermined load current value and the immediately preceding load current value with the third threshold Th3 and the fourth threshold Th4, respectively, or may compare the absolute value of the difference between the predetermined load current value and the immediately preceding load current value with a second absolute value A2, which is the absolute value of the third threshold Th3 and the fourth threshold Th4.

[0038] Furthermore, when the calculated value C is the ratio between a predetermined load current value and the load current value immediately preceding it, for example, the third threshold value Th3 is the reciprocal of the fourth threshold value Th4, and each is a positive value. In this case, the determination unit 133 may compare the ratio between the predetermined load current value and the load current value immediately preceding it with the third threshold value Th3 and the fourth threshold value Th4, respectively, or may compare the absolute value of the difference between the predetermined load current value and the load current value immediately preceding it with a value obtained by multiplying the predetermined load current value or the immediately preceding load current value by (1 - third threshold value Th3).

[0039] The first time T1 is a time correlated with the acquisition time T of the actual current value or the load current value. For example, the first time T1 is an integer multiple of the acquisition time T of the actual current value or the load current value. In this embodiment, the first time T1 is set to less than 1 second, for example, 0.8 seconds.

[0040] However, even if the cleaning tool 1 is stationary on the part to be cleaned F, if the user intentionally keeps the cleaning tool 1 fixed on the part to be cleaned F to press the rotating cleaning body 11 against the part to be cleaned F near the wall to scrape out dust from the wall, or if the cleaning tool 1 is stationary on the part to be cleaned F that has a high rotational load, such as a long-pile carpet, it may be better not to implement the power reduction control, taking into account the efficiency of dust removal by the rotating cleaning body 11. Therefore, preferably, the control means 13 determines whether to implement the power reduction control, taking into account the magnitude of the predetermined load current value of the motor 12.

[0041] In this embodiment, when the determination unit 133 determines that the predetermined load current value of the motor 12 detected by the current detection unit 131 is equal to or greater than a predetermined fifth threshold Th5 that is greater than the second threshold Th2, the control unit 13 does not execute power reduction control, even if the calculated value remains equal to or greater than the first threshold Th1 and equal to or less than the second threshold Th2 for a first time T1. In this embodiment, the fifth threshold Th5 is set to a value greater than the fourth threshold Th4. This fifth threshold Th5 is preferably set to a value greater than the load current value of the motor 12 when the rotating cleaning body 11 is idling while the cleaning tool 1 is cooled to a predetermined temperature or lower.

[0042] These controls will be described with reference to the flowchart shown in Fig. 5. In the flowchart shown in Fig. 5, the case will be described in which the calculated value C is the difference between a predetermined load current value and the immediately preceding load current value, the absolute values ​​of the first threshold value Th1 and the second threshold value Th2 are equal, and the absolute values ​​of the third threshold value Th3 and the fourth threshold value Th4 are equal.

[0043] First, in step S1, the control means 13 determines in the determination unit 133 whether the load current value I(t) is equal to or greater than the fifth threshold value Th5, or whether the absolute value of the calculated value C is greater than the second absolute value A2. That is, in step S1, the control means 13 determines in the determination unit 133 whether the load current value I(t) is equal to or greater than the fifth threshold value Th5, or whether the calculated value C is smaller than the third threshold value Th3, or whether the calculated value C is greater than the fourth threshold value Th4. If it is determined in step S1 that the load current value I(t) is equal to or greater than the fifth threshold value Th5, or whether the absolute value of the calculated value C is greater than the second absolute value A2, that is, if the answer is YES in step S1, the control means 13 resets the determination value in the determination unit 133 in step S2, that is, sets the determination value of a counter or the like to 0, and proceeds to step S5. These steps S1 and S2 reset the judgment by the judgment unit 133 if the load current value I(t) is greater than or equal to the fifth threshold value Th5, or if the calculated value C is smaller than the third threshold value Th3, or if the calculated value C is greater than the fourth threshold value Th4.

[0044] If it is determined in step S1 that the load current value I(t) is less than the fifth threshold value Th5 and the absolute value of the calculated value C is less than or equal to the second absolute value A2, i.e., if the answer is NO in step S1, then in step S3, the control means 13 determines in the determination unit 133 whether the absolute value of the calculated value C is less than or equal to the first absolute value A1. That is, in step S3, the control means 13 determines in the determination unit 133 whether the calculated value C is greater than or equal to the first threshold value Th1 and less than or equal to the second threshold value Th2. If it is determined in step S3 that the absolute value of the calculated value C is less than or equal to the first absolute value A1, i.e., if the answer is YES in step S3, then in step S4, the determination value is incremented by 1, and the process proceeds to step S5. That is, if the load current value I(t) is less than the fifth threshold value Th5 and the calculated value C is greater than or equal to the first threshold value Th1 and less than or equal to the second threshold value Th2, the determination value is incremented by 1.

[0045] In step S5, the control means 13 determines whether the determination value is equal to or greater than the predetermined number threshold in the determination unit 133. If it is determined in step S5 that the determination value is equal to or greater than the predetermined number threshold, that is, if the answer is YES in step S5, then in step S6, the control means 13 performs power reduction control, resets the determination value to 0, and proceeds to step S1.

[0046] Also, in step S5, if it is determined that the determination value is not equal to or greater than the predetermined number of times threshold, that is, if the result of step S5 is NO, the process proceeds directly to step S1.

[0047] These determinations and controls are performed for each acquisition time T, so that the count threshold becomes a value correlated with the first time T1, and in this embodiment, is (first time T1) / (acquisition time T). For example, as in this embodiment, when the acquisition time T is 0.1 seconds and the first time T1 is 0.8 seconds, the count threshold is 8.

[0048] Furthermore, if it is determined in step S3 that the absolute value of calculated value C is not equal to or less than first absolute value A1, i.e., if step S3 returns NO, the process proceeds to step S5. That is, if steps S1 and S3 determine that calculated value C is smaller than first threshold value Th1 and larger than third threshold value Th3, or larger than second threshold value Th2 and smaller than fourth threshold value Th4, the determination value is not incremented or reset, and the determination proceeds with the value of the determination value maintained. Therefore, the determination result in step S5 remains the same as the determination result in the previous step S5, and the control of steps S1 to S5 is repeated once more, i.e., the determination is postponed by the acquisition time T, so that the first time T1 for determining the first condition is substantially extended.

[0049] Furthermore, in the case of (2) above, the rotational load is relatively small, and therefore the load current value of the motor 12 is relatively small. Also, the load current value when the cleaning tool 1 is moved backward is approximately constant regardless of the type of the part to be cleaned F, so it is assumed that the fluctuation of the load current value from the minimum value within a predetermined time in the past reflects the rotational load caused by the part to be cleaned F.

[0050] Therefore, the control means 13 also performs power reduction control when a second condition based on a change in the load current value of the motor 12 within a predetermined second time T2 is satisfied. That is, in this embodiment, the second condition is a type determination condition based on the rotational load of the part to be cleaned F. In the illustrated example, the second condition is a type determination condition for the part to be cleaned that determines whether the part to be cleaned F has a small rotational load, such as a wooden floor.

[0051] In this embodiment, the second condition is that there is small fluctuation in the load current value of the motor 12 within the predetermined second time T2. As an example, the second condition is that a calculated value based on at least the predetermined load current value of the motor 12 and the minimum value of the load current value of the motor 12 within the predetermined second time T2 is equal to or less than a predetermined fluctuation threshold.

[0052] Specifically, when the determination unit 133 determines that the difference and / or ratio of the predetermined load current value to the minimum value of the load current value within a predetermined second time period is equal to or less than a predetermined first variation threshold, the control means 13 outputs a signal from the determination unit 133 to the power variable unit 130 to reduce the drive power of the motor 12 or implement power reduction control to set the drive power to a relatively small value. This determination by the determination unit 133 may take into account whether or not it has been determined that the calculated value C is equal to or greater than a predetermined sixth threshold and / or whether or not the predetermined load current value is equal to or greater than a predetermined first threshold current value and / or less than a predetermined second threshold current value that is greater than the first threshold current value.

[0053] The second time T2 is a time that correlates with the time T at which the actual current value or the load current value is acquired. For example, the second time T2 is an integer multiple of the time T at which the actual current value or the load current value is acquired. In this embodiment, the second time T2 is set to be equal to or longer than the time it takes a typical user to move the cleaning tool 1 backward from the start to stop or move forward again. The moving speed of the cleaning tool 1 by a typical user is 0.5 m / second as specified in predetermined standards such as JIS, and the time it takes a typical user to move the cleaning tool 1 forward from the start to stop is approximately 0.8 to 1 second, and the time it takes a typical user to move the cleaning tool 1 backward from the start to stop or move forward again is approximately 1.5 to 2 seconds. In this embodiment, since the determination unit 133 can make a determination using the first time T1 in a short time, the control means 13 sets the second time T2 to be longer than the first time T1, and it is preferable to set the time required for the determination (2) above to be longer than the time required for the determination (1) above, thereby improving the determination accuracy and suppressing a decrease in the rotation speed of the motor 12, i.e., the rotation speed of the rotary cleaning body 11, in the cleaning area F where the rotation load is large, such as a carpet. Preferably, the second time T2 is equal to a predetermined threshold time, which is set to, for example, 2.0 seconds in this embodiment.

[0054] The first variation threshold and the sixth threshold are each a value sufficiently smaller than the load current value, for example, on the order of about 1 / 10 of the load current value.

[0055] However, the type of the part to be cleaned F may be determined by a known type determination means that determines the type of the part to be cleaned F based on the acquisition of information indicating the part to be cleaned F, such as an image or contact resistance.

[0056] In this embodiment, the control means 13 may also perform power reduction control when a second condition is met in addition to the first condition in the above case (1).

[0057] In this embodiment, "reducing the drive power of the motor 12" or "setting the drive power to a relatively small value" in the power reduction control means that the control means 13 sets the drive power of the motor 12 to a predetermined first drive power equal to or greater than 0 using the power variable unit 130. The first drive power is a relatively small drive power among multiple drive powers that can be set by the power variable unit 130, or a drive power that results in a small rotation speed that is safe for a user to touch the rotating cleaning body 11, etc.

[0058] In the above cases (1) and (2), the first drive powers may be the same but are preferably different. In the case of the above case (1), since it is assumed that the cleaning tool 1 or the rotary cleaning body 11 is far from the cleaned portion F, it is preferable to further reduce the rotation speed of the rotary cleaning body 11 to a rotation speed that is safe even if the user touches the rotary cleaning body 11. Therefore, the one first drive power set according to the determination result of the above case (1) is smaller than the other first drive powers set according to the determination result of the above case (2). For example, the power variable unit 130 sets the duty ratio of the PWM signal for the one first drive power set according to the determination result of the above case (1) to 20%, and sets the duty ratio of the PWM signal for the other first drive power set according to the determination result of the above case (2) to 40%, 30%, or the like.

[0059] Therefore, if the drive power of the motor 12 satisfies the first condition in one first drive power state, and if the drive power of the motor 12 satisfies the second condition in another first drive power state, the drive power of the motor 12 will be maintained as is. Also, if the drive power of the motor 12 satisfies the first condition in another first drive power state, the drive power of the motor 12 will be further reduced.

[0060] Additionally, power reduction control may be performed when an object is entangled in the rotary cleaning body 11 or when the motor 12 overheats. In particular, when an object is entangled in the rotary cleaning body 11, the drive power of the motor 12 may be reduced to 0. In these cases, the load current value of the motor 12 and the change in the load current value within a predetermined time may also be used to make the determination.

[0061] On the other hand, the above-described power increase control is a control that aims to increase the rotation speed of motor 12 from a relatively low state and thereby increase the rotation speed or rotation torque of rotary cleaning body 11. Any condition may be set as the condition for implementing power increase control, but in this embodiment, attention is focused on the movement of cleaning tool 1 reciprocating back and forth while in contact with the area to be cleaned F during cleaning, and control means 13 implements power increase control when at least a part of this reciprocating movement is detected based on the load current value of motor 12.

[0062] That is, when the user pushes the cleaning tool 1 forward and the cleaning tool 1 or the rotary cleaning body 11 moves forward while in contact with the part to be cleaned F, a downward load is applied to the cleaning tool 1, pressing the rotary cleaning body 11 against the part to be cleaned F, and as shown in FIG. 6, the load current value I(t) increases depending on the type of part to be cleaned F. On the other hand, when the user pulls the cleaning tool 1 backward and the cleaning tool 1 or the rotary cleaning body 11 moves backward while in contact with the part to be cleaned F, a pulling force acts diagonally upward on the cleaning tool 1 via the connecting tube 14, reducing the pressure of the rotary cleaning body 11 against the part to be cleaned F, and the load current value I(t) decreases. Furthermore, when the user stops the cleaning tool 1 on the part to be cleaned F, the load current value is smaller when the cleaning tool 1 moves forward and larger when it moves backward.

[0063] Therefore, when the determination unit 133 determines that the predetermined load current value of the motor 12 detected by the current detection unit 131 has at least increased within the predetermined second time T2, the control unit 13 outputs a signal from the determination unit 133 to the power variable unit 130 to increase the drive power of the motor 12 or set the drive power to a relatively high level. Preferably, when the determination unit 133 determines that the predetermined load current value of the motor 12 detected by the current detection unit 131 has at least increased and then decreased within the predetermined second time T2, the control unit 13 outputs a signal from the determination unit 133 to the power variable unit 130 to increase the drive power of the motor 12 or set the drive power to a relatively high level. In particular, in this embodiment, when the determination unit 133 determines that the predetermined load current value of the motor 12 detected by the current detection unit 131 has at least increased within the predetermined second time T2, the control unit 13 determines that the third condition has been satisfied, that is, the predetermined load current value of the motor 12 has at least increased, then decreased, and then further increased within the predetermined second time T2, the control unit 13 outputs a signal from the determination unit 133 to the power variable unit 130 to increase the drive power of the motor 12 or set the drive power to a relatively high level.

[0064] Specifically, the control means 13 determines that the load current value has increased when the determination unit 133 determines that the difference and / or ratio of the predetermined load current value to the minimum value of the load current value within a first predetermined time period in the past is equal to or greater than a predetermined second fluctuation threshold. The determination of the current increase in the determination unit 133 may take into account whether or not it has determined that the calculated value C is equal to or greater than a predetermined seventh threshold and / or whether or not the predetermined load current value is equal to or greater than a predetermined third threshold current value.

[0065] Furthermore, the control means 13 determines that the load current value has decreased when the determination unit 133 determines that the difference and / or ratio of the predetermined load current value to the maximum value of the load current value within the past second predetermined time is equal to or less than a predetermined third variation threshold. This determination by the determination unit 133 may take into account whether or not it has determined that the calculated value C is equal to or greater than a predetermined eighth threshold and / or whether or not the predetermined load current value is equal to or greater than a predetermined fourth threshold current value and / or less than a predetermined fifth threshold current value that is greater than the fourth threshold current value.

[0066] The first predetermined time and the second predetermined time may be different or the same. The first predetermined time and the second predetermined time are each shorter than the second time T2, and the sum of the first predetermined time and the second predetermined time is equal to or less than the second time T2. For example, in this embodiment, the first predetermined time and the second predetermined time are each 1.0 to 2.0 seconds.

[0067] The second and third fluctuation thresholds, the seventh and eighth thresholds are each sufficiently smaller than the load current value, for example, on the order of about 1 / 10 of the load current value. For example, the second and third fluctuation thresholds are equal in absolute value but opposite in sign when they are thresholds for the difference between the minimum load current value within a first predetermined time in the past and the maximum load current value within a second predetermined time in the past, i.e., the second and third fluctuation thresholds are positive and negative, respectively. When they are thresholds for the ratio between the minimum load current value within the first predetermined time in the past and the maximum load current value within a second predetermined time in the past, they are reciprocals of each other.

[0068] In this embodiment, when the judgment unit 133 detects that the load current value of the motor 12 has increased from an increase standby state in which it judges whether the load current value of the motor 12 has increased, the control means 13 enters a decrease standby state in which it judges whether the load current value of the motor 12 has decreased, and when it detects that the load current value of the motor 12 has decreased from the decrease standby state, it enters a re-increase standby state in which it judges whether the load current value of the motor 12 has increased, and when it detects that the load current value of the motor 12 has increased from the re-increase standby state, it performs power increase control.

[0069] In this embodiment, "increasing the drive power of the motor 12" or "setting a relatively large drive power" in the power increase control refers to the control means 13 setting the drive power of the motor 12 to a predetermined second drive power with a duty of 100% or less using the power variable unit 130. The second drive power is a relatively large drive power among the multiple drive powers that can be set by the power variable unit 130, and is larger than the first drive power. In this embodiment, the power variable unit 130 sets the duty ratio of the PWM signal for the second drive power to, for example, 100%. Therefore, if the drive power of the motor 12 satisfies the third condition at the second drive power, the drive power of the motor 12 will be maintained as is.

[0070] However, if it is determined that the first condition is satisfied within the second time T2 during which the determination unit 133 determines whether the predetermined load current value of the motor 12 is increasing or decreasing, the control means 13 prioritizes power reduction control and initializes and cancels the determination whether the predetermined load current value of the motor 12 is increasing or decreasing.

[0071] That is, the determination in (1) above is performed regardless of the drive power of the motor 12. That is, even if the drive power of the motor 12 is reduced to the first drive power, the determination in (1) above is performed.

[0072] FIG. 7 shows the state transitions of the motor 12 due to the above-described power reduction control and power increase control. In the illustrated example, when the motor 12 is started after starting operation, the motor 12 is driven with a relatively small drive power and is in a low-speed rotation state. As another example, the motor 12 may be started with a first drive power or the like and be in a high-speed rotation state. When the third condition is satisfied from the low-speed rotation state, the motor 12 transitions to a high-speed rotation state, i.e., a drive state using the second drive power, through power increase control. Furthermore, when the first condition and / or the second condition is satisfied from the high-speed rotation state, the motor 12 transitions to a low-speed rotation state, i.e., a drive state using the first drive power, through power reduction control, or to a stopped state. Furthermore, when the first condition is satisfied during the reduction standby state or the re-increase standby state in the low-speed rotation state, the increase determination and decrease determination are canceled, and the motor transitions to the increase standby state, which is the initial state of the power increase control. Therefore, when the cleaning tool 1 is performing cleaning on a surface F to be cleaned that has a heavy rotational load such as a carpet, the motor 12 and the rotary cleaning body 11 rotate at high speed at the second drive power with a duty ratio of 100%, and when the cleaning tool 1 is performing cleaning on a surface F to be cleaned that has a light rotational load such as a wooden floor, the motor 12 and the rotary cleaning body 11 rotate at medium or low speed at the first drive power with a duty ratio of 40% or 30%, and when the cleaning tool 1 is stationary on a surface F to be cleaned that has a light rotational load such as a wooden floor, the motor 12 and the rotary cleaning body 11 rotate at low speed at the other first drive power with a duty ratio of 20%. At the end of operation, the drive power of the motor 12 becomes a duty ratio of 0%, and the motor 12 and the rotary cleaning body 11 stop rotating.

[0073] Furthermore, the control means 13 preferably does not perform any processing related to changing the driving power of the motor 12 for a certain period of time after at least one of starting the motor 12 and changing the driving power of the motor 12, i.e., power increase control or power decrease control. Here, not performing any processing related to changing the driving power means at least one of not measuring the load current value of the motor 12, not determining whether to increase or decrease the driving power of the motor 12, and not increasing or decreasing the driving power of the motor 12. In the simplest example, the control means 13 waits for a certain period of time before processing after starting the motor 12 and after changing the driving power of the motor 12, i.e., after power increase control or power decrease control.

[0074] Thus, according to the first embodiment, when the calculated value C based on at least a predetermined load current value of the motor 12 and the load current value immediately before it satisfies the first condition that the calculated value C is equal to or greater than a first threshold value Th1 and equal to or less than a second threshold value Th2, which is smaller than the load current value, for a predetermined first time T1, the control means 13 reduces the driving power of the motor 12. Therefore, it is possible to quickly detect a state in which it is desired to reduce the driving power of the motor 12, such as a state in which the cleaning tool 1 or the rotating cleaning body 11 is away from the part to be cleaned F, and quickly reduce the driving power, thereby enabling power saving.

[0075] In other words, when the cleaning tool 1 or the rotary cleaning body 11 moves away from the part to be cleaned F, the rotary cleaning body 11 starts to rotate freely, so the load current value of the motor is lower than when the cleaning tool 1 is placed on the part to be cleaned F, especially on a part to be cleaned F with a small rotational load such as a wooden floor, and fluctuations in the load current value are significantly smaller than when cleaning a part to be cleaned F such as a wooden floor or carpet. Therefore, in this embodiment, if a state with extremely little change in the load current value continues for a predetermined time, it is assumed that the cleaning tool 1 or the rotary cleaning body 11 has moved away from the part to be cleaned F, and the control means 13 reduces the driving force of the motor 12, thereby reducing the rotational torque of the rotary cleaning body 11. In this embodiment, the control means 13 compares the predetermined load current value of the motor 12 with the immediately preceding load current value, so that the determination can be made in a shorter time than when comparing the load current value with the maximum or minimum value over a predetermined time in the past. Not only that, but also the memory unit 132 for storing the load current value does not need to be excessively large, resulting in a simple configuration. In addition, there is no need for a safety device to detect when the cleaning tool 1 or the rotating cleaning body 11 is away from the area to be cleaned F and reduce the driving power of the motor 12, so the cleaning tool 1 can be made lighter and simpler, while ensuring both safety and cleaning performance.

[0076] The load current value of the motor 12 includes factors attributable to individual differences in the motor 12, such as deviations in winding resistance, variations in the efficiency of converting power into rotational energy, temperature, dirt and entanglement on the rotating cleaning body 11 rotated by the motor 12, the type of part to be cleaned F, and the manner in which the cleaning tool 1 is used. Therefore, by setting the calculated value C to a value obtained by subtracting the immediately preceding load current value from a predetermined load current value, the variations in the load current value attributable to these factors can be suppressed, and the use of this calculated value C improves the judgment accuracy of the control means 13.

[0077] In this case, by setting the first threshold value Th1 to a negative value and the second threshold value Th2 to a positive value whose absolute value is equal to that of the first threshold value Th1, it becomes possible to compare the calculated value C with the first threshold value Th1 and the second threshold value Th2, respectively, simply by comparing the absolute value of the calculated value C with the first absolute value A1, which is the absolute value of the first threshold value Th1 and the second threshold value Th2, thereby reducing the comparison and judgment process by the control means 13 compared to when the calculated value C is compared with the first threshold value Th1 and the second threshold value Th2, respectively.

[0078] Alternatively, by setting the calculated value C to a value obtained by dividing a predetermined load current value by the immediately preceding load current value, it is possible to suppress variations in the load current value due to conditions such as variations in the motor 12, temperature, dirt on the rotating cleaning body 11, entanglement of hair, the type of the part to be cleaned F, and how the cleaning tool 1 is used, and by using this calculated value C, the judgment accuracy of the control means 13 is improved.

[0079] In this case, by setting the second threshold value Th2 to the reciprocal of the first threshold value Th1, it is possible to compare the calculated value C with the first threshold value Th1 and the second threshold value Th2, respectively, simply by comparing the absolute value of the difference between a specified load current value and its immediately preceding load current value with the value obtained by multiplying the specified load current value or the immediately preceding load current value by (1 - first threshold value Th1), instead of the calculated value C. Therefore, the comparison and judgment process by the control means 13 can be reduced compared to when the calculated value C is compared with the first threshold value Th1 and the second threshold value Th2, respectively.

[0080] Furthermore, when the calculated value C is smaller than the first threshold value Th1 and larger than a third threshold value Th3 smaller than the first threshold value Th1, or when the calculated value C is larger than the second threshold value Th2 and smaller than a fourth threshold value Th4 larger than the second threshold value Th2, the control means 13 extends the first time T1. In this way, if the change in the load current value is small enough to be attributed to an external factor such as the detection accuracy of the current detection unit 131 or noise from the suction source 3, the control means 13 suspends the judgment and waits for the temporary current change to subside before continuing the judgment, thereby minimizing the delay in the judgment compared to when the judgment is canceled.

[0081] When the predetermined load current value is equal to or greater than a fifth threshold Th5 that is greater than the second threshold Th2, the control means 13 does not perform control to reduce the driving power of the motor 12. This allows control not to reduce the driving power of the motor 12, thereby ensuring the torque of the rotating cleaning body 11 and dust removal, for example, when it is assumed that the user is intentionally maintaining a high load state by pressing the rotating cleaning body 11 against the part to be cleaned F near the wall and fixing the cleaning tool 1 on the part to be cleaned F to scrape out dust near the wall, or when the cleaning tool 1 is stationary on the part to be cleaned F such as a carpet that has a high rotational load.

[0082] The control means 13 reduces the drive power of the motor 12 when the second condition based on the change in the load current value within a predetermined second time T2 longer than the first time T1 is satisfied, so that it is possible to determine the type of the part to be cleaned F based on the second condition based on the change in the load current value over a longer period of time than the determination of the first condition. Therefore, it is possible to quickly determine whether the cleaning tool 1 or the rotary cleaning body 11 has attached to or detached from the part to be cleaned F within the relatively short first time T1, and to quickly reduce the drive power to reduce the rotational torque of the rotary cleaning body 11. At the same time, it is possible to improve the accuracy of the determination of the type of the part to be cleaned F by taking the time within the second time T2 longer than the first time T1, and to prevent the drive power of the motor 12 from being reduced for the part to be cleaned F with a large rotational load, such as a carpet, for which it is undesirable to reduce the drive power of the motor 12.

[0083] The control means 13 increases the drive power of the motor 12 when a third condition is satisfied, that is, when the predetermined load current value at least increases within a predetermined second time T2, preferably when the predetermined load current value at least increases and then decreases within the predetermined second time T2, and in this embodiment when the third condition is satisfied, that is, when the predetermined load current value increases, decreases, and then increases within the second time T2, the control means 13 can detect, for example, that a user has moved the cleaning tool 1 back and forth while it is placed on the part to be cleaned F, based on fluctuations in the predetermined load current value. Therefore, by increasing the drive power of the motor 12 in response to detection of this movement while the motor 12 is being driven with low drive power, the rotational torque of the rotary cleaning body 11 can be easily increased in response to a cleaning operation in which the cleaning tool 1 is moved back and forth while in contact with the part to be cleaned F, without using a safety device or the like that detects attachment or detachment of the cleaning tool 1 or the rotary cleaning body 11 to or from the part to be cleaned F.

[0084] At this time, if the first condition is met within the second time T2, it is assumed that the user touched the rotary cleaning body 11 while the cleaning tool 1 or the rotary cleaning body 11 was away from the part to be cleaned F, or that the user touched the rotary cleaning body 11 and then released it. Therefore, in this case, by canceling the determination of an increase or decrease in the predetermined load current value, even if the user subsequently touches the rotary cleaning body 11 again, the control means 13 does not increase the drive power of the motor 12, and the rotational torque of the rotary cleaning body 11 can be kept low, thereby maintaining a higher level of safety.

[0085] By including the cleaning tool 1 described above, it is possible to provide an electric vacuum cleaner CL that is energy-saving, has a simple configuration, and is capable of achieving both safety and cleaning performance.

[0086] (Second embodiment) Next, a second embodiment will be described with reference to Figures 8 and 9. Note that the same components and functions as those in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

[0087] In this embodiment, the cleaning tool 1 is equipped with a safety device 9 that detects attachment or detachment of the cleaning tool 1 or the rotary cleaning body 11 to the part to be cleaned F. The safety device 9 is a known device that directly detects attachment or detachment from the part to be cleaned F in response to attachment or detachment from the part to be cleaned F. The control means 13 performs power reduction control in response to detecting that the safety device 9 has been detached from the part to be cleaned F. In this case, it is not necessary to use the load current value of the motor 12 to detect that the cleaning tool 1 or the rotary cleaning body 11 has been detached from the part to be cleaned F, as in the first embodiment.

[0088] Therefore, in this embodiment, the load current value of the motor 12 is used to detect when the cleaning tool 1 is stationary while in contact with the part to be cleaned F, such as a wooden floor, which has a small rotational load. In other words, when the cleaning tool 1 is stationary while in contact with the part to be cleaned F, such as a wooden floor, which has a small rotational load, it is assumed that the load current value of the motor 12 is small and that the load current value or fluctuation in the load current value remains small for a predetermined period of time or longer.

[0089] Therefore, as in the first embodiment, when a first condition is satisfied in which a calculated value C based on a predetermined load current value of the motor 12 and the load current value immediately before that value is equal to or greater than a first threshold value Th1 and is equal to or smaller than a second threshold value Th1, which is smaller than the load current value, for a predetermined first time T1, the control means 13 reduces the drive power of the motor 12 to a first drive power or performs power reduction control to set the first drive power to a relatively small value. That is, in this embodiment, the first condition is a condition for determining that the part to be cleaned F is stationary, where the rotation load is small.

[0090] The first time T1, the first threshold value Th1, and the second threshold value Th2 may be the same as or different from those in the first embodiment. For example, in this embodiment, the determination of whether the cleaning tool 1 or the rotating cleaning body 11 is attached to or detached from the part to be cleaned F is mainly left to the safety device 9, which determines whether the cleaning tool 1 or the rotating cleaning body 11 is stationary in contact with the part to be cleaned F, such as a wooden floor, which has a small rotational load. Therefore, a short-term determination is basically unnecessary to ensure safety, and the first time T1 is set longer than in the first embodiment to improve the determination accuracy. As an example, the first time T1 is set to 1.5 seconds. The first threshold value Th1 and the second threshold value Th2 are the same as those in the first embodiment.

[0091] As described above, according to this embodiment, when a first condition is satisfied that a calculated value C based on at least a predetermined load current value of the motor 12 and the load current value immediately before that value is equal to or greater than a first threshold value Th1 and equal to or less than a second threshold value Th2, which is smaller than the load current value, for a predetermined first time T1, the control means 13 reduces the driving power of the motor 12. Therefore, since this embodiment has a configuration similar to that of the first embodiment, it is possible to quickly detect a state in which it is desired to reduce the driving power of the motor 12, such as when the cleaning tool 1 is stationary on a cleaned surface F with a small rotational load, such as a wooden floor, and quickly reduce the driving power, thereby achieving the same effects as the first embodiment, such as power saving.

[0092] Furthermore, with regard to the power increase control, since the determination of whether the cleaning tool 1 or the rotary cleaning body 11 is in contact with the cleaned portion F is primarily left to the safety device 9, as shown in FIGS. 8 and 9 , when the control means 13 determines that the predetermined load current value I(t) of the motor 12 detected by the current detection unit 131 has met a third condition of increasing within a predetermined second time T2, preferably when the control means 13 determines that the predetermined load current value I(t) of the motor 12 detected by the current detection unit 131 has met the third condition of increasing and then decreasing within the predetermined second time T2, the determination unit 133 outputs a signal to the power variable unit 130 to increase the drive power of the motor 12 or set it to a relatively large drive power. Furthermore, a further condition for the determination may be that the load current value I(t) of the motor 12 exceeds a predetermined load current threshold ITh. The determination of whether the load current value has increased may be the same as or different from that in the first embodiment. That is, the second variable threshold may be the same as or different from that in the first embodiment. Therefore, compared to the first embodiment, which detects whether a predetermined load current value of the motor 12 increases, then decreases, and then increases again within a predetermined second time T2, the time required to determine the third condition is shorter, and the driving power of the motor 12, i.e., the rotation speed of the rotating cleaning body 11, can be increased quickly.

[0093] In each embodiment, the vacuum cleaner CL is not limited to one that generates negative pressure or suction force using the suction source 3, but may be one that uses the rotation of the rotary cleaning body 11 to sweep up and accumulate dust in the separating section 4.

[0094] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention to these embodiments. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0095] 11 Rotating cleaning body 12 motors 13 Control measures CL vacuum cleaner

Claims

1. A motor; a rotating cleaning body rotated by the motor; a control means for controlling the motor; The control means reduces the drive power of the motor when a first condition is satisfied in which a calculated value based on at least a predetermined load current value of the motor and a load current value immediately before the predetermined load current value is equal to or greater than a first threshold value and is equal to or smaller than a second threshold value that is smaller than the load current value for a predetermined first time period. A vacuum cleaner characterized by:

2. The calculated value is a value obtained by subtracting the immediately preceding load current value from the predetermined load current value.

2. The vacuum cleaner according to claim 1.

3. The first threshold is a negative value, and the second threshold is a positive value whose absolute value is equal to that of the first threshold.

3. The vacuum cleaner according to claim 2.

4. The calculated value is a value obtained by dividing the predetermined load current value by the immediately preceding load current value.

2. The vacuum cleaner according to claim 1.

5. The second threshold is the reciprocal of the first threshold.

5. The vacuum cleaner according to claim 4.

6. The control means extends the first time period when the calculated value is smaller than the first threshold value and larger than a third threshold value that is smaller than the first threshold value, or larger than the second threshold value and smaller than a fourth threshold value that is larger than the second threshold value.

2. The vacuum cleaner according to claim 1.

7. The control means does not perform control to reduce the driving power of the motor when the predetermined load current value is equal to or greater than a fifth threshold value that is greater than the second threshold value.

2. The vacuum cleaner according to claim 1.

8. The control means reduces the drive power of the motor when a second condition based on a change in the load current value within a predetermined second time period that is longer than the first time period is satisfied.

2. The vacuum cleaner according to claim 1.

9. The control means increases the drive power of the motor when a third condition is satisfied that the predetermined load current value has increased at least within a predetermined second time period that is longer than the first time period, and when the first condition is satisfied within the second time period, the control means cancels the determination of the increase or decrease of the predetermined load current value.

2. The vacuum cleaner according to claim 1.

Images