WO2022207060A1

WO2022207060A1 - Vacuum cleaner

Info

Publication number: WO2022207060A1
Application number: PCT/EP2021/058077
Authority: WO
Inventors: Ulrik Danestad
Original assignee: Aktiebolaget Electrolux
Priority date: 2021-03-29
Filing date: 2021-03-29
Publication date: 2022-10-06
Also published as: EP4312695A1

Abstract

A vacuum cleaner (1) is disclosed comprising a fan (3), an electric motor (5) configured to power the fan (3), a control arrangement (21), and an output unit (7, 7'). The control arrangement (21) is configured to monitor a quantity representative of an electric current (Im) supplied to the electric motor (5) and is configured to increase a voltage (Vm) supplied to the electric motor (5) in response to a detected decrease in electric current (Im) supplied to the electric motor (5). The control arrangement (21) is further configured to output a notification via the output unit (7, 7') if the voltage (Vm) supplied to the electric motor (5) exceeds a threshold limit (Tl) during a first predetermined time (t1).

Description

Vacuum Cleaner

TECHNICAL FIELD

The present disclosure relates to a vacuum cleaner. More specifically the present disclosure relates to a vacuum cleaner comprising a fan, an electric motor configured to power the fan, a control arrangement, and an output unit.

BACKGROUND

A vacuum cleaner is an apparatus that uses a motor/fan unit to create a partial vacuum in order to obtain an air flow for sucking up dust and dirt from surfaces, such as floors, carpets, furniture, curtains, and the like. The motor/fan unit usually comprises a centrifugal fan and an electric motor configured to power, i.e. rotate, the centrifugal fan to suck air through a dust separation unit such as a dust bag, a cyclone separator, or the like.

Several different types of vacuum cleaners exit, including upright/stick type vacuum cleaners, robotic vacuum cleaners, canister vacuum cleaners, and hand-held vacuum cleaners, such as pistol grip hand-held cleaners, and the like. The fast progress in development of high- capacity batteries and small electric motors, such as brushless motors, has made battery powered vacuum cleaners able to compete with traditional corded cleaners. Partly as a reason thereof, a current trend for vacuum cleaners is light weighted, small, and easy to handle battery powered vacuum cleaners.

Many vacuum cleaners comprise one or more filters arranged to filter air flowing through the vacuum cleaner in addition to a dust separating unit. As an example, a vacuum cleaner may comprise a filter arranged between a dust separation unit and the fan, i.e. a filter downstream of the dust separation unit and upstream of the fan, and/or a filter arranged between the fan and an air outlet of the vacuum cleaner, i.e. a filter downstream of the fan and upstream of the air outlet of the vacuum cleaner.

During use of a vacuum cleaner, a dust separation unit and filters of the above mentioned types are filled with dust and may consequently become clogged. A clogged dust separation unit, and/or a clogged filter, significantly reduces the performance of the vacuum cleaner. Moreover, received service calls indicate that clogged filters and poorly cleaned and emptied dust separation units are common and that they can cause damage and premature wear of components of the vacuum cleaner. Therefore, it is a great advantage if a user of a vacuum cleaner is informed when it is time to empty the dust separation unit and/or when it is time to clean one or more filters of the vacuum cleaner. Accordingly, an indicator showing when to empty the dust separation unit, and/or when to clean one or more filters, increases performance and reliability of the vacuum cleaner, and leads to a more satisfied consumer.

A traditional way of informing a user of the vacuum cleaner of the fact that the dust separation unit is full of dust, and/or that one or more filters of the vacuum cleaner is/are clogged, is to use a mechanical pressure sensor. Such mechanical pressure sensors usually comprise a spring loaded body visual to a user, for example via a transparent window, or the like. When the difference in pressure between air inside a suction channel of the vacuum cleaner and ambient air exceeds a threshold value, the spring loaded body is moved to a certain position such that the user can recognize that the dust separation unit is full of dust, and/or that one or more filters of the vacuum cleaner is/are clogged.

Such mechanical pressure sensors are widely used in vacuum cleaners due to the simplicity thereof. However, mechanical pressure sensors are also associated with some problems and drawbacks. One drawback is that a mechanical pressure sensor usually can only show a current instantaneous pressure difference. As an example, if temporarily restricting airflow through the vacuum cleaner, for example by placing a hand on an air inlet of the vacuum cleaner or by placing the air inlet against another type of air flow restricting body, the spring loaded body will be moved to the position indicating to the user that the dust separation unit is full, and/or that one or more filters of the vacuum cleaner is/are clogged. When the temporary restriction is removed, the spring loaded body returns to its initial position. This also means that the user usually has to monitor the position of the spring loaded body during operation of the vacuum cleaner to be able to make a qualified estimation of whether the dust separation unit is full, and/or of whether it is time to clean one or more filters of the vacuum cleaner.

Another drawback with a mechanical pressure sensor is that they are difficult to use in some types of vacuum cleaners in a reliable manner, in particular in vacuum cleaners operating with lower suction levels, such as smaller vacuum cleaners, battery powered vacuum cleaners, hand-held vacuum cleaners, stick-type vacuum cleaners, robotic vacuum cleaners, and the like. This is because of the lower pressure difference between air inside a suction channel of the vacuum cleaner and ambient air for such vacuum cleaners and the fact that the spring loaded body inevitably is subjected to some frictional forces which may cause the spring loaded body to become stuck at a certain position. As an example, a traditional corded canister cleaner may operate at a power of around 900W whereas a vacuum cleaner of the above mentioned types may operate at a power level of approximately 100W, which puts demands on a system or arrangement for indicating a full dust separation unit, and/or clogged filter/filters of the vacuum cleaner. As a reason thereof, there are very few vacuum cleaners of the above mentioned types on the market provided with a system or arrangement for indicating a full dust separation unit, and/or clogged filter/filters of the vacuum cleaner. Attempts have been made to solve these problems for example by implementing a long spring arranged to bias the spring loaded body. However, also such solutions are sensitive to friction and the low difference in pressure which results in an unreliable arrangement for indicating a full dust separation unit, and/or clogged filter/filters of the vacuum cleaner.

Another way of informing a user of the vacuum cleaner when to empty the dust separation unit, and/or to clean one or more filters, is to use a timer counting the operation time of the vacuum cleaner. When the vacuum cleaner has been operated a certain time, the user is informed that it is time to empty the dust separation unit, and/or to clean one or more filters, for example by activating a light emitting unit. Such solutions are simple and cost efficient but are also inexact. That is, these types of solutions do not take into account the actual current clogging level of the dust separation unit, and/or of the more filters. Therefore, if using the vacuum cleaner for cleaning heavily soiled surfaces, the user will be informed too late, and if using the vacuum cleaner for more clean surfaces, the user will be informed too early. Accordingly, such solutions can cause damage and premature wear of components of the vacuum cleaner if the vacuum cleaner is used for cleaning heavily soiled surfaces and can be annoying for a user if the vacuum cleaner is used for cleaning more clean surfaces.

Moreover, generally, on today’s consumer market, it is an advantage if products, such as vacuum cleaners and associated components, systems, and arrangements, have conditions and/or characteristics suitable for being manufactured and assembled in a cost-efficient manner.

SUMMARY

It is an object of the present invention to overcome, or at least alleviate, at least some of the above-mentioned problems and drawbacks.

According to an aspect of the invention, the object is achieved by a vacuum cleaner comprising a fan, an electric motor configured to power the fan, a control arrangement, and an output unit. The control arrangement is configured to monitor a quantity representative of an electric current supplied to the electric motor and is configured to increase a voltage supplied to the electric motor in response to a detected decrease in electric current supplied to the electric motor. The control arrangement is further configured to output a notification via the output unit if the voltage supplied to the electric motor exceeds a threshold limit during a first predetermined time.

Since the control arrangement is configured to output a notification via the output unit if the voltage supplied to the electric motor exceeds the threshold limit during the first predetermined time, a vacuum cleaner is provided capable of indicating to a user of the vacuum cleaner when it is time to empty a dust separation unit, and/or when it is time to clean one or more filters, of the vacuum cleaner in a simple, efficient, and accurate manner.

This is because the electric current supplied to the electric motor is indicative of a flow resistance through the vacuum cleaner which in turn is indicative of a clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. In more detail, a clogged or partially clogged dust separation unit, and/or filter, of the vacuum cleaner increases the flow resistance through the vacuum cleaner and reduces the flow rate of air through the vacuum cleaner as well as the work performed by the fan and the electric motor. As a result thereof, the electric current supplied to the electric motor is decreased. Since the control arrangement is configured to increase a voltage supplied to the electric motor in response to a detected decrease in electric current supplied to the electric motor, the level of voltage supplied to the electric motor can give a clear and accurate indication of the clogging level of a dust separation unit and of one or more filters of the vacuum cleaner. Thus, because the control arrangement is configured to output the notification based on voltage supplied to the electric motor, a vacuum cleaner is provided having conditions for providing an indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner in a simple, efficient, and accurate manner.

Moreover, a cost-efficient solution is provided because the control arrangement is configured to output the notification based on the voltage supplied to the electric motor, which circumvents the need for an unreliable mechanical pressure sensor, or other type of devices or systems, for indicating the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. In other words, a vacuum cleaner is provided capable of indicating to a user of the vacuum cleaner that it is time to empty a dust separation unit, and/or to clean one or more filters, of the vacuum cleaner in a simple, efficient, and accurate manner, while having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Furthermore, conditions are provided for being able to output an accurate indication also for vacuum cleaners operating at lower power levels, such as small sized vacuum cleaners, battery powered vacuum cleaners, hand-held vacuum cleaners, stick-type vacuum cleaners, robotic vacuum cleaners, and the like, without significantly adding manufacturing and assembling costs of the vacuum cleaner.

Moreover, because the vacuum cleaner is capable of outputting an accurate indication of the clogging level of the vacuum cleaner, it can be ensured that the vacuum cleaner is more likely to be emptied and cleaned when needed which in turn increases the performance of the vacuum cleaner and reduced the risk of damage and premature wear of components of the vacuum cleaner.

Accordingly, a vacuum cleaner is provided overcoming, or at least alleviating, at least some of the above-mentioned problems and drawbacks. As a result, the above-mentioned object is achieved.

Optionally, the vacuum cleaner comprises a battery configured to supply electricity to the electric motor by an amount controlled by the control arrangement. Thereby, a user-friendly vacuum cleaner is provided capable of outputting an accurate indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner, without significantly adding manufacturing and assembling costs of the vacuum cleaner.

Optionally, the control arrangement is configured to control the voltage supplied to the electric motor by reducing the voltage supplied to the electric motor from a power source. Thereby, a simple and accurate control is provided of the voltage supplied to the electric motor. Moreover, conditions are provided for increasing the voltage supplied to the electric motor when needed.

In addition, in embodiments in which the vacuum cleaner comprises a power source in the form of a battery configured to supply electricity to the electric motor, a margin is provided for reductions in battery voltage for example caused by a change of state of charge of the battery during operation of the vacuum cleaner and/or caused by one or more degraded/damaged battery cells of the battery. As a result thereof, conditions are provided for compensating such reductions in battery voltage so as to provide more constant power levels of the electric motor of the vacuum cleaner. In this manner, a more user-friendly vacuum cleaner is provided.

Optionally, the control arrangement is configured to input the voltage supplied to the electric motor by monitoring a current voltage at the battery and current voltage reduction data. Thereby, a simple, efficient, and accurate input is provided of the voltage supplied to the electric otor.

Optionally, the control arrangement is configured to decrease the voltage supplied to the electric motor in response to a detected increase in electric current supplied to the electric motor. Thereby, an automatic control of the power level of the electric motor is provided. That is, as mentioned above, the electric current supplied to the electric motor is indicative of a flow resistance through the vacuum cleaner. Thus, by increasing the voltage supplied to the electric motor in response to a detected decrease in electric current supplied to the electric motor and by decreasing the voltage supplied to the electric motor in response to a detected increase in electric current supplied to the electric motor, an automatic control is provided of the power level of the electric motor.

As an example, if temporarily restricting airflow through the vacuum cleaner, for example by placing an air inlet of the vacuum cleaner against an air flow restricting body, the flow resistance through the vacuum cleaner is increased and the flow rate of air through the vacuum cleaner is reduced, as well as the work performed by the fan and by the electric motor. As a result thereof, the electric current supplied to the electric motor is decreased. In response to the decrease in electric current supplied to the electric motor, the control arrangement increases the voltage supplied to the electric motor and will thereby compensate for the reduction in work performed by the fan.

Likewise, if a dust separation unit, and/or one or more filters, of the vacuum cleaner becomes partially clogged, the flow resistance through the vacuum cleaner increases and the flow rate of air through the vacuum cleaner decreases as well as the work performed by the fan and by the electric motor. As explained above, the electric current supplied to the electric motor will also decrease. In response to the decrease in electric current supplied to the electric motor, the control arrangement will increase the voltage supplied to the electric motor and will thereby compensate for the reduction in work performed by the fan.

Furthermore, if a temporary restriction is removed from an air inlet of the vacuum cleaner or if dust is removed from a dust separation unit, and/or from one or more filters, of the vacuum cleaner, the flow resistance through the vacuum cleaner decreases and the flow rate of air through the vacuum cleaner increases as well as the work performed by the fan and the work performed by the electric motor. Thereby, the electric current supplied to the electric motor also increases. In response to a detected increase in electric current supplied to the electric motor, the control arrangement will decrease the voltage supplied to the electric motor and will thereby compensate for the increased work performed by the fan and by the electric motor.

Thus, as explained above, due to these features, an automatic control of the power level of the electric motor is provided in a simple, efficient, and reliable manner. As a further result thereof, the cleaning efficiency of the vacuum cleaner can be improved over a wider range of operational conditions. Furthermore, a more user-friendly vacuum cleaner is provided having conditions for operating at less varying power levels.

In addition, in embodiments in which the vacuum cleaner comprises a power source in the form of a battery configured to supply electricity to the electric motor, a reduction in battery voltage caused by a change of state of charge of the battery during operation of the vacuum cleaner can be compensated for so as to provide more constant power levels of the vacuum cleaner regardless of the current state of charge of the battery. In this manner, a more user- friendly vacuum cleaner is provided.

Furthermore, in embodiments in which the vacuum cleaner comprises a power source in the form of a battery configured to supply electricity to the electric motor, a reduction in battery voltage caused by one or more degraded/damaged battery cells of the battery can be compensated for so as to provide more constant power levels of the vacuum cleaner regardless of the current state of charge of the battery. In this manner, a more user-friendly vacuum cleaner is provided.

Optionally, the control arrangement is configured regulate the voltage supplied to the electric motor to obtain a substantially constant power level of the electric motor. Thereby, a more user-friendly vacuum cleaner is provided capable of reducing or circumventing occurrences in voltage reductions from the power source. Moreover, a vacuum cleaner is provided capable of compensating for a current clogging level of the vacuum cleaner in a simple, efficient, and reliable manner. Furthermore, a vacuum cleaner is provided having conditions for an improved cleaning efficiency over a wider range of operational conditions of the vacuum cleaner.

Optionally, the output unit comprises a light emitting device, such as a light emitting diode. Thereby, a simple, efficient, and low-cost component can be utilized for outputting the notification to a user of the vacuum cleaner. Thereby, a vacuum cleaner is provided having conditions and characteristics suitable for being manufactured and assembled in a cost- efficient manner. Optionally, the control arrangement is configured to cancel the outputting of the notification if the voltage supplied to the electric motor declines below the threshold limit during a second predetermined time. Thereby, an even more user-friendly vacuum cleaner is provided. This is because, as explained above, if a temporary restriction is removed from an air inlet of the vacuum cleaner or if dust is removed from a dust separation unit, and/or one or more filters, of the vacuum cleaner, the flow resistance through the vacuum cleaner decreases and the flow rate of air through the vacuum cleaner increases, as well as the work performed by the fan and the work performed by the electric motor. Thereby, the electric current supplied to the electric motor also increases.

In response to a detected increase in electric current supplied to the electric motor, the control arrangement may decrease the voltage supplied to the electric motor. As mentioned above, the voltage supplied to the electric motor is indicative of the clogging level of the vacuum cleaner. Accordingly, by cancelling the outputting of the notification if the voltage supplied to the electric motor declines below the threshold limit during a second predetermined time, a simple and reliable cancellation is provided when it is not needed to remove dust from a dust separation unit, and/or one or more filters, of the vacuum cleaner. Accordingly, in this manner, an even more user-friendly vacuum cleaner is provided.

Optionally, the control arrangement is configured to set a magnitude of the threshold limit based on stored data on previous voltage levels supplied to the electric motor. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because data on previous voltage levels supplied to the electric motor can indicate how the clogging level of the dust separation unit, and/or one or more filters, of the vacuum cleaner has evolved in order to provide a more accurate indication of the clogging level based on a current use situation of the vacuum cleaner. As a further result thereof, an even more user-friendly vacuum cleaner is provided.

Optionally, the control arrangement is configured to set a magnitude of the threshold limit based on an estimation of an operational condition of the vacuum cleaner. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because the estimation of an operational condition of the vacuum cleaner can indicate whether a clogging is temporary or persistent which can provide a more accurate and reliable indication of the clogging level of the vacuum cleaner. As a further result thereof, a more user-friendly vacuum cleaner is provided.

Optionally, the estimation of the operational condition involves an estimation of whether the vacuum cleaner is used for cleaning a soft or hard surface. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because when cleaning a soft surface, such as a textile carpet, the flow resistance through an air inlet of the vacuum cleaner is usually higher than when cleaning a harder surface, such as a floor surface. Thus, since the estimation of the operational condition involves an estimation of whether the vacuum cleaner is used for cleaning a soft or hard surface, the control arrangement is capable of separating between a situation where the voltage supplied to the electric motor increases as a result of cleaning a softer surface and a situation in which the voltage supplied to the electric motor increases as a result of a clogged dust separation unit, and/or a clogged filter, of the vacuum cleaner. Thus, in this manner, the control arrangement is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner to a user of the vacuum cleaner which in turn provides a more user-friendly vacuum cleaner.

Optionally, the estimation of the operational condition involves an estimation of a type of nozzle being attached to the vacuum cleaner. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because different types of nozzles can provide different flow resistance levels through the vacuum cleaner. Accordingly, since the estimation of the operational condition involves an estimation of a type of nozzle being attached to the vacuum cleaner, the control arrangement is able to estimate whether an increase in voltage supplied to the electric motor is caused by a more flow restricting nozzle or is caused by a clogged dust separation unit, and/or one or more filters of the vacuum cleaner. Thus, in this manner, the control arrangement is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner to a user of the vacuum cleaner which in turn provides a more user-friendly vacuum cleaner.

Optionally, the vacuum cleaner comprises an environment sensor configured to provide data representative of a current environment in which the vacuum cleaner operates, and wherein the control arrangement is configured to set a magnitude of the threshold limit based on data from the environment sensor. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because data from the environment sensor may indicate a current surface being cleaned and/or other aspects of the environment in which the vacuum cleaner operates. In this manner, the control arrangement can separate between situations where the voltage supplied to the electric motor increases as a result of an environmental factor, such as a softer surface being cleaned, and situations in which the voltage supplied to the electric motor increases as a result of a clogged dust separation unit, and/or one or more clogged filters, of the vacuum cleaner. Thus, in this manner, the control arrangement is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner to a user of the vacuum cleaner which in turn provides a more user- friendly vacuum cleaner.

Optionally, the vacuum cleaner comprises a nozzle, a brush arranged at the nozzle, and an electric brush motor configured to rotate the brush, and wherein the control arrangement is configured to set the threshold limit based on one or more electrical quantities of electricity supplied to the electric brush motor. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because the electrical quantities of electricity supplied to the electric brush motor can provide an indication of whether the vacuum cleaner currently is cleaning a soft surface, such as a textile carpet, or a harder surface, such as a floor surface. That is, a high moving resistance of the brush is indicative of a softer surface being cleaned, such as a textile carpet, and a lower moving resistance of the brush is indicative of a harder surface being cleaned, such as a floor surface.

Moreover, the moving resistance of the brush affects the electrical quantities of electricity supplied to the electric brush motor. In this manner, the control arrangement can separate between situations where the voltage supplied to the electric motor increases as a result of the current surface being cleaned, and situations in which the voltage supplied to the electric motor increases as a result of a clogged dust separation unit, and/or a clogged filter, of the vacuum cleaner. Thus, in this manner, the control arrangement is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner to a user which in turn provides a more user-friendly vacuum cleaner.

Optionally, the control arrangement is configured to set the threshold limit to a higher value in case the one or more electrical quantities indicate a high moving resistance of the brush and is configured to set the threshold limit to a lower value in case the one or more electrical quantities indicate a lower moving resistance of the brush. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of a dust separation unit, and/or one or more filters, of the vacuum cleaner. This is because a high moving resistance of the brush is indicative of a softer surface being cleaned, such as a textile carpet, and a lower moving resistance of the brush is indicative of a harder surface being cleaned, such as a floor surface. Moreover, the moving resistance of the brush affects the electrical quantities of electricity supplied to the electric brush motor. In this manner, the control arrangement can separate between situations where the voltage supplied to the electric motor increases as a result of the current surface being cleaned, and situations in which the voltage supplied to the electric motor increases as a result of a clogged dust separation unit, and/or a clogged filter, of the vacuum cleaner. Thus, in this manner, the control arrangement is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner to a user which in turn provides a more user-friendly vacuum cleaner.

Optionally, the vacuum cleaner is a hand-held vacuum cleaner, a stick-type vacuum cleaner, or a robotic vacuum cleaner. Thereby, a user-friendly vacuum cleaner is provided capable of indicating to a user of the vacuum cleaner when it is time to empty a dust separation unit, and/or when it is time to clean one or more filters, of the vacuum cleaner in a simple, efficient, accurate, and cost-efficient manner.

Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of the invention, including its particular features and advantages, will be readily understood from the example embodiments discussed in the following detailed description and the accompanying drawings, in which:

Fig. 1 schematically illustrates a vacuum cleaner according to some embodiments,

Fig. 2 illustrates a graph showing different electrical quantities of the vacuum cleaner illustrated in Fig. 1 during a use session,

Fig. 3 schematically illustrates a vacuum cleaner according to some further embodiments, and

Fig. 4 illustrates a vacuum cleaner according to some further embodiments.

DETAILED DESCRIPTION Aspects of the present invention will now be described more fully. Like numbers refer to like elements throughout. Well-known functions or constructions will not necessarily be described in detail for brevity and/or clarity.

Fig. 1 schematically illustrates a vacuum cleaner 1 according to some embodiments of the present disclosure. According to the illustrated embodiments, the vacuum cleaner 1 is a stick-type vacuum cleaner comprising an elongated body with a handle 2 at a first end 10 and a nozzle 11 arranged at a second end 10’ of the vacuum cleaner 1 , wherein the second end 10’ of the vacuum cleaner 1 is opposite to the first end 10. According to further embodiments, and as is further explained herein, the vacuum cleaner 1 may be another type of vacuum cleaner 1, such as a hand-held vacuum cleaner, a canister vacuum cleaner, a robotic vacuum cleaner, a central vacuum cleaner, or the like. According to the embodiments illustrated in Fig. 1, the vacuum cleaner 1 is configured to be operated using one hand on the handle 2 of the vacuum cleaner 1.

The vacuum cleaner 1 comprises a fan 3 and an electric motor 5 configured to power, i.e. rotate, the fan 3. The fan 3 may comprise a centrifugal fan. The electric motor 5 may be a brushless or a brushed electric motor. The vacuum cleaner 1 comprises an airflow path 18 extending from an air inlet 14 of the vacuum cleaner 1 at the nozzle 11 to an air outlet 16 of the vacuum cleaner 1. The fan 3 is configured to generate an airflow through the airflow path 18 in a direction from the air inlet 14 towards the air outlet 16 during operation of the vacuum cleaner 1. According to the illustrated embodiments, the vacuum cleaner 1 comprises a dust separating unit 22 in the form of a centrifugal separator. According to further embodiments, the vacuum cleaner 1 may comprise another type of dust separating unit 22, such as a dust bag, a filter, or the like. The dust separating unit 22 is arranged in the airflow path 18 at a position upstream of the fan 3 and is configured to separate dust, and other types of particles and matter, from air flowing through the airflow path 18.

According to the illustrated embodiments, the vacuum cleaner 1 further comprises a first filter unit 24 and a second filter unit 26 each arranged in the airflow path 18. Each of the first and second filter units 24, 26 is configured to further separate fine particles from air flowing through the airflow path 18 of the vacuum cleaner 1. According to the illustrated embodiments, each of the first and second filter units 24, 26 is arranged at a position in the airflow path 18 between the dust separation unit 22 and the fan 3 of the vacuum cleaner 1. In other words, according to the illustrated embodiments, each of the of the first and second filter units 24, 26 is arranged at a position in the airflow path 18 downstream of the dust separation unit 22 and upstream of the fan 3 of the vacuum cleaner 1. The vacuum cleaner 1 may comprise one or more further filter units such as for example a filter unit arranged in the airflow path 18 at a position between the fan 3 and the air outlet 16 of the vacuum cleaner 1 , i.e. arranged at a position downstream of the fan 3 and upstream of the air outlet 16 of the vacuum cleaner 1. Apart from separating particles from the airflow, a further purpose of a filter, such a filter unit of the above mentioned type, may be to attenuate noise generated by the vacuum cleaner 1 during operation thereof.

The wording upstream and downstream, as used herein, relates to the relative positions of objects in relation to an intended air flow direction through the airflow path 18. As an example, the feature that a first object is arranged upstream of a second object in the airflow path 18 means that the first object is arranged before the second object seen relative to the intended airflow direction through the airflow path 18. As another example, the feature that a first object is arranged downstream of a second object in the airflow path 18 means that the first object is arranged after the second object seen relative to the intended airflow direction of through the airflow path 18.

According to the illustrated embodiments, the vacuum cleaner 1 comprises a power source 9’ in the form of a battery 9 which is configured to supply electricity to the electric motor 5. According to further embodiments, the vacuum cleaner 1 may comprise a cord for connection to a socket connected to a power grid for providing electricity to the electric motor 5. The vacuum cleaner 1 further comprises a control arrangement 21 and an output unit 7. The control arrangement 21 is operably connected to the power source 9’, to the electric motor 5, and to the output unit 7. Moreover, according to the illustrated embodiments, the control arrangement 21 is operably connected to an actuator 27 of the vacuum cleaner 1 allowing activation and deactivation of the vacuum cleaner 1. According to the embodiments illustrated in Fig. 1, the actuator 27 is arranged in a region of the handle 2. Moreover, according to the illustrated embodiments, the battery 9 is configured to supply electricity to the electric motor 5 by an amount controlled by the control arrangement 21. According to the illustrated embodiments, the output unit 7 comprises a light emitting diode, i.e. a type of light emitting unit. According to further embodiments, the output unit 7 may comprise another type of device or arrangement configured to output a signal to a user upon request of the control arrangement 21 , as is further explained herein.

The control arrangement 21 is configured to monitor a quantity representative of an electric current Im supplied to the electric motor 5. Moreover, the control arrangement 21 is configured to increase a voltage Vm supplied to the electric motor 5 in response to a detected decrease in electric current Im supplied to the electric motor 5. The control arrangement 21 is further configured to output a notification via the output unit 7 if the voltage Vm supplied to the electric motor 5 exceeds a threshold limit during a first predetermined time t1.

As is further explained herein, due to these features, a vacuum cleaner 1 is provided capable of indicating to a user of the vacuum cleaner 1 when it is time to empty the dust separation unit 22, and/or when it is time to clean the filters 24, 26, of the vacuum cleaner 1 in a simple, efficient, accurate, and cost-efficient manner.

Fig. 2 illustrates a graph showing different electrical quantities of the vacuum cleaner 1 illustrated in Fig. 1 during a use session of the vacuum cleaner 1. The horizontal axis indicates elapsed time t, and the vertical axis indicates the magnitude of the respective electrical quantity. Below, simultaneous reference is made to Fig. 1 and Fig. 2, if not indicated otherwise.

In more detail, the graph of Fig. 2 illustrates the current voltage Vb at the battery 9 of the vacuum cleaner 1. The current voltage Vb at the battery 9 may for example be measured at the battery 9, or at electrical wires connected to poles of the battery 9, such as electrical wires extending between the battery 9 and the control arrangement 21 , or at poles of the control arrangement 21 connected to the battery 9 via electrical wires. As seen in Fig. 2, the voltage Vb at the battery 9 declines slightly during use of the vacuum cleaner 1 because of a decrease in the state of charge of the battery 9. The battery 9 may comprise a number of battery cells, such as such as lithium-ion battery cells, lithium polymer batteries cells, or nickel-metal hydride battery cells, or the like.

Moreover, the graph of Fig. 2 illustrates the voltage Vm supplied to the electric motor 5. As clearly seen in Fig. 2, the voltage Vm supplied to the electric motor 5 is, at least during normal operation of the vacuum cleaner 1 , lower than the current voltage Vb at the battery 9 of the vacuum cleaner 1. That is, according to these embodiments, the control arrangement 21 is configured to control the voltage Vm supplied to the electric motor 5 by reducing the voltage supplied from the battery 9 to the electric motor 5. According to some embodiments, the control arrangement 21 is configured to reduce the voltage supplied from the battery 9 to the electric motor 5 using Pulse Width Modulation (PWM), also referred to as Pulse Duration Modulation (PDM). According to further embodiments, the control arrangement 21 may be configured to reduce the voltage supplied from the battery 9 to the electric motor 5 using another type of method or device, such as for example by controlling the ohmic resistance of a resistor device. The voltage Vm supplied to the electric motor 5 may for example be measured at the electric motor 5, or at electrical wires connected to poles of the electric motor 5, such as electrical wires extending between the control arrangement 21 and the electric motor 5, or at poles of the control arrangement 21 connected to the electric motor 5 via electrical wires. According to some embodiments, the control arrangement 21 may input the voltage Vm supplied to the electric motor 5 by measuring the voltage Vm supplied to the electric motor 5. However, according to some embodiments of the herein described, the control arrangement 21 is configured to input the voltage Vm supplied to the electric motor 5 by monitoring a current voltage Vb at the battery 9 and current voltage reduction data. Thus, in these embodiments, the control arrangement 21 may for example multiply a current voltage reduction factor of the current voltage reduction data and the monitored current voltage Vb at the battery 9 to obtain the voltage Vm supplied to the electric motor 5. In this manner, a simple, efficient, and accurate input is provided of the voltage Vm supplied to the electric motor 5.

In embodiments in which the control arrangement 21 is configured to reduce the voltage supplied from the battery 9 to the electric motor 5 using Pulse Width Modulation (PWM), the control arrangement 21 may be configured to input the voltage Vm supplied to the electric motor 5 by monitoring a current voltage Vb at the battery 9 and current Pulse Wdth Modulation data. Thus, in such embodiments, the control arrangement 21 may for example multiply a current Pulse Width Modulation reduction factor and the monitored current voltage Vb at the battery 9 to obtain the voltage Vm supplied to the electric motor 5.

Moreover, the graph of Fig. 2 illustrates the electric current Im supplied to the electric motor 5. As mentioned above, the control arrangement 21 is configured to monitor a quantity representative of an electric current Im supplied to the electric motor 5 to detect changes in in electric current Im supplied to the electric motor 5, i.e. to detect increases and decreases in electric current Im supplied to the electric motor 5. The control arrangement 21 may input a current electric current Im supplied to the electric motor 5 by measuring the electric current Im supplied to the electric motor 5. The electric current Im supplied to the electric motor 5 may for example be measured at the electric motor 5, or at electrical wires connected to poles of the electric motor 5, such as electrical wires extending between the control arrangement 21 and the electric motor 5, or at poles of the control arrangement 21 connected to the electric motor 5 via electrical wires.

The electric current Im supplied to the electric motor 5 varies with the load and rotational speed of the electric motor 5, which in turn varies with the flow resistance of air through the airflow path 18 of the vacuum cleaner 1. The flow resistance of air through the airflow path 18 of the vacuum cleaner 1 varies with the clogging level of the dust separation unit 22 and the clogging level of the filters 24, 26 of the vacuum cleaner 1. The clogging level of the dust separation unit 22 and the clogging level of the filters 24, 26 of the vacuum cleaner 1 varies with the amount of dust, and other type of matter, collected in the dust separation unit 22 and in the filters 24, 26 of the vacuum cleaner 1. The clogging level of the dust separation unit 22 and the clogging level of the filters 24, 26 are together in some places herein referred to as the clogging level of the airflow path 18 or the clogging level of the vacuum cleaner 1.

As mentioned above, the control arrangement 21 is configured to increase the voltage Vm supplied to the electric motor 5 in response to a detected decrease in electric current Im supplied to the electric motor 5. Moreover, according to embodiments herein, the control arrangement 21 is configured to decrease the voltage Vm supplied to the electric motor 5 in response to a detected increase in electric current Im supplied to the electric motor 5. In Fig. 2, the power level P of the electric motor 5 is indicated. In the above described manner, an automatic control of the power level P of the electric motor 5 is provided. The power level P of the electric motor 5 may be given by the formula electric current Im supplied to the electric motor 5 multiplied with the voltage Vm supplied to the electric motor 5. As seen in Fig. 2, according to these embodiments, the control arrangement 21 is configured regulate the voltage Vm supplied to the electric motor 5 to obtain a substantially constant power level P of the electric motor 5.

In Fig. 2, different event lines e1 - e6 are indicated. At a first event line e1 , the vacuum cleaner 1 has currently been started and is used for cleaning a harder type of floor surface. That is, at the first event line e1 , the nozzle 11 of the vacuum cleaner 1 is positioned on a harder type of floor surface, such as a wooden floor surface, a linoleum carpet, or the like.

At a second event line e2, the nozzle 11 of the vacuum cleaner 1 reaches a softer type of surface, such as a textile carpet. The softer type of surface increases the air flow resistance through the nozzle 11 of the vacuum cleaner 1. As a result, as can be seen in Fig. 2 at the second event line e2, the electric current Im supplied to the electric motor 5 decreases and the control arrangement 21 increases the voltage Vm supplied to the electric motor 5 to maintain a constant power level P of the electric motor 5 of the vacuum cleaner 1. Still, the voltage Vm supplied to the electric motor 5 is lower than the threshold limit Tl indicated in Fig. 2. At a third event line e3 indicated in Fig. 2, the nozzle 11 of the vacuum cleaner 1 again reaches the harder type of floor surface. As a result, the flow resistance through the nozzle 11 of the vacuum cleaner 1 decreases and the electric current Im supplied to the electric motor 5 increases. The control arrangement 21 reduces the voltage Vm supplied to the electric motor 5 in order to maintain the constant power level P of the electric motor 5 of the vacuum cleaner 1. To the right of the third event line e3, a similar event is occurring where the nozzle 11 of the vacuum cleaner 1 first reaches a softer type of surface and then again reaches the harder type of floor surface. The electric current Im supplied to the electric motor 5 and the voltage Vm supplied to the electric motor 5 changes in the above described manner.

However, as can be noted, for example at a fourth event line e4 indicated in Fig. 2, the voltage Vm supplied to the electric motor 5 is at a higher level at the fourth event line e4 than at the first event line e1 even though the nozzle 11 is positioned against the same type of floor surface at the fourth event line e4 as at the first event line e1. The higher voltage Vm supplied to the electric motor 5 is caused by the fact that clogging level of the airflow path 18 has increased as a result of the use of the vacuum cleaner 1. In other words, the clogging level of the dust separation unit 22 and the clogging level of the filters 24, 26 of the vacuum cleaner 1 have increased as a result of the use of the vacuum cleaner 1. As understood from the above described, the higher clogging level of the airflow path 18 causes a higher flow resistance through the airflow path 18 which causes a drop in electric current Im supplied to the electric motor 5 which the control arrangement 21 compensates for by increasing the voltage Vm supplied to the electric motor 5 in order to maintain a constant power level P of the vacuum cleaner 1.

At a fifth event line e5 indicated in Fig. 2, the air inlet 14 of the vacuum cleaner 1 has been positioned against a flow restricting body which causes the voltage Vm supplied to the electric motor 5 to exceed the threshold limit Tl. However, as seen in Fig. 2, the flow restricting body is removed from the air inlet 14 of the vacuum cleaner 1 at a sixth event line e6 indicated in Fig. 2 which causes the voltage Vm supplied to the electric motor 5 to drop below the threshold limit Tl. The time t between the fifth and sixth event lines e5, e6 is shorter than the length of first predetermined time t1 indicated in Fig. 2. Therefore, the control arrangement 21 does not output a notification via the output unit 7 at these events.

As seen to the right of the sixth event line e6 indicated in Fig. 2, the nozzle 11 is again positioned against the harder type of floor surface followed by a time period in which the nozzle 11 is positioned against the softer type of floor surface, such as a textile carpet. The voltage Vm supplied to the electric motor 5 is kept below the threshold limit Tl during these events. However, at a seventh event line e7, the voltage Vm supplied to the electric motor 5 again reaches above the threshold limit Tl as a result of the air inlet 14 of the vacuum cleaner 1 being positioned against a flow restricting body. However, the object is removed in a region of an eight event line e8 indicated in Fig. 2, wherein the time t between the seventh and eight event lines e7, e8 is shorter than the length of the first predetermined time t1 indicated in Fig. 2. Therefore, the control arrangement 21 does not output a notification via the output unit 7 at these events.

At a ninth event line e9 indicated in Fig. 2, the nozzle 11 of the vacuum cleaner 1 is again positioned against the softer type of floor surface, such as a textile carpet. As a result thereof, and because of the fact that the clogging level of the airflow path 18 of the vacuum cleaner 1 has increased during the use of the vacuum cleaner 1, the voltage Vm supplied to the electric motor 5 surpasses the threshold limit Tl. In the example given in Fig. 2, the vacuum cleaner 1 is used for cleaning the softer type of floor surface until a tenth event line e10 indicated in Fig. 2. The time t between the ninth and tenth event lines e9, e10 is longer than the length of the first predetermined time tl Therefore, the control arrangement 21 outputs a notification to a user of the vacuum cleaner 1 via the output unit 7 at the end of the first predetermined time t1 indicated in Fig. 2. The user of the vacuum cleaner 1 is thereby notified that it is time to empty the dust separation unit 22, and/or to clean one or more filters 24, 26, of the vacuum cleaner 1.

Because the control arrangement 21 is configured to output the notification based on the voltage Vm supplied to the electric motor 5 in the above described manner, a vacuum cleaner 1 is provided having conditions for providing an indication of the clogging level of the dust separation unit 22, and/or the filters 24, 26, of the vacuum cleaner 1 in a simple, efficient, and accurate manner.

Moreover, a cost-efficient solution is provided because the control arrangement 21 is configured to output the notification based on the voltage Vm supplied to the electric motor 5, which circumvents the need for an unreliable mechanical pressure sensor, or other type of device, for indicating the clogging level of the dust separation unit 22, and/or filters 24, 26, of the vacuum cleaner 1. In other words, a vacuum cleaner 1 is provided capable of indicating to a user of the vacuum cleaner 1 that it is time to empty the dust separation unit 22, and/or to clean filters 24, 26, of the vacuum cleaner 1 in a simple, efficient, and accurate manner, while the vacuum cleaner 1 has conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. Moreover, because the vacuum cleaner 1 is capable of outputting an accurate indication of the clogging level of the vacuum cleaner 1 , it can be ensured that the vacuum cleaner 1 is more likely to be emptied and cleaned when needed which in turn increases the performance of the vacuum cleaner 1 and reduced the risk of damage and premature wear of components of the vacuum cleaner 1.

As described in the following, according to the illustrated embodiments, the control arrangement 21 is configured to cancel the outputting of the notification if the voltage Vm supplied to the electric motor 5 declines below the threshold limit Tl during a second predetermined time t2. As seen at the tenth event line e10 indicated in Fig. 2, the voltage Vm supplied to the electric motor 5 declines below the threshold limit Tl. Moreover, in this example, the voltage Vm supplied to the electric motor 5 is lower than the threshold limit Tl during a time period which is longer than the second predetermined time t2. Thus, in the illustrated example, the control arrangement 21 cancels the outputting of the notification at the end of the second predetermined time t2 indicated in Fig. 2. In this manner, a more user- friendly vacuum cleaner is provided because the output of notifications caused by temporary restrictions of the airflow path 18 of the vacuum cleaner 1 can be avoided. Moreover, in cases where a user has cleaned/emptied the dust separation unit 22, and/or the filters 24,

26, the control arrangement 21 will cancel the outputting of the notification. This is because the voltage Vm supplied to the electric motor 5 will decline below the threshold limit Tl due to the lower flow resistance through the airflow path 18 of the vacuum cleaner 1.

In addition to the above described, the vacuum cleaner 1 may comprise a sensor arrangement configured to sense whether a compartment accommodating the dust separation unit 22, and/or the filters 24, 26, has been opened. Such a sensor arrangement may for example comprise a magnetic body and a hall effect sensor configured to sense the presence of the magnetic body by sensing the magnetic field of the magnetic body. The control arrangement 21 may be operably connected to the sensor arrangement, such as to the hall effect sensor in the above given example and may cancel the outputting of the notification if the sensor arrangement indicates that the compartment the dust separation unit 22, and/or the filters 24, 26, is or has been opened.

The first and second predetermined times t1, t2 as referred to herein, may also be referred to as a first and a second time period t1 , t2. Therefore, throughout this disclosure, the wording “first predetermined time t1” may be replaced with the wording “first predetermined time period t1” and the wording “second predetermined time t2” may be replaced with the wording “second predetermined time period t2”. The first predetermined time t1 may have a length within the range of a number of seconds to a few minutes. Likewise, second predetermined time t2 may have a length within the range of a number of seconds to a few minutes.

According to some embodiments, the control arrangement 21 may be configured to cancel the outputting of the notification if the voltage Vm supplied to the electric motor 5 declines below a second threshold limit during the second predetermined time t2, wherein the second threshold limit is different than the threshold limit Tl referred to above. According to such embodiments, the “threshold limit Tl” referred to above may also be referred to as a “first threshold limit Tl”.

According to some embodiments, the control arrangement 21 may analyse data on previous voltage levels Vm’ supplied to the electric motor 5 to estimate an operational condition of the vacuum cleaner 1 and/or to draw conclusions on whether the vacuum cleaner 1 is used for cleaning a soft or hard surface. Moreover, as is further explained herein, the control arrangement 21 may be configured to set a magnitude of the threshold limit Tl based on stored data on previous voltage levels Vm’ supplied to the electric motor 5. As an example, if the stored data on previous voltage levels Vm’ indicates that voltage Vm supplied to the electric motor 5 has reached relative low levels in a period preceding a current operation period, the control arrangement 21 may set the threshold limit Tl to a higher value. Likewise, if the stored data on previous voltage levels Vm’ indicates that voltage Vm supplied to the electric motor 5 has reached relative high levels in a period preceding the current operation period, the control arrangement 21 may set the threshold limit Tl to a lower value. In this manner, the control arrangement 21 is able to provide more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user- friendly vacuum cleaner 1.

Moreover, the control arrangement 21 may be configured to set a magnitude of the threshold limit Tl based on an estimation of an operational condition of the vacuum cleaner 1, wherein the estimation of the operational condition may involve an estimation of whether the vacuum cleaner 1 currently is used for cleaning a soft or hard surface. That is, according to such embodiments, the control arrangement 21 may increase the threshold limit Tl if it is estimated that the vacuum cleaner 1 currently is used for cleaning a softer surface and may reduce the threshold limit Tl if it is estimated that the vacuum cleaner 1 currently is used for cleaning a harder type of surface. In this manner, the control arrangement 21 is able to provide more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user-friendly vacuum cleaner 1. Furthermore, as an alternative, or in addition, the estimation of the operational condition may involve an estimation of a type of nozzle 11 being attached to the vacuum cleaner 1. That is, different nozzles provide different air flow resistance through the air inlet 14 of the vacuum cleaner 1. Moreover, many vacuum cleaners, such as the vacuum cleaner 1 illustrated in Fig. 1 can be operated with the nozzle 11 being removed. Thus, according to these embodiments, the control arrangement 21 may estimate which type of nozzle 11 that currently is being attached to the vacuum cleaner 1 and set the magnitude of the threshold limit Tl in response thereto. The control arrangement 21 may set the threshold limit Tl to a higher value in case a highly flow restricting nozzle is estimated to be attached to the vacuum cleaner 1 and may set the threshold limit Tl to a lower value in case a low flow restricting nozzle, or no nozzle, is estimated to be attached to the vacuum cleaner 1. In this manner, the control arrangement 21 is able to provide more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user- friendly vacuum cleaner 1.

According to the embodiments illustrated in Fig. 1, the vacuum cleaner 1 comprises a brush 13 arranged at the nozzle 11 of the vacuum cleaner 1. Moreover, the vacuum cleaner 1 comprises an electric brush motor 15 configured to rotate the brush 13. The electric brush motor 15 is supplied with electricity from the battery 9 by an amount controlled by the control arrangement 21. According to the illustrated embodiments, the control arrangement 21 is configured to set a magnitude of the threshold limit Tl based on one or more electrical quantities of electricity supplied to the electric brush motor 15. The one or more electrical quantities of electricity supplied to the electric brush motor 15 may comprise a voltage supplied to the electric brush motor 15 and/or an electric current supplied to the electric brush motor 15.

In more detail, according to the illustrated embodiments, the control arrangement 21 is configured to set the threshold limit Tl to a higher value in case the one or more electrical quantities indicate a high moving resistance of the brush 13 and is configured to set the threshold limit Tl to a lower value in case the one or more electrical quantities indicate a lower moving resistance of the brush 13. Thereby, conditions are provided for obtaining an even more accurate and reliable indication of the clogging level of the dust separation unit 22, and/or filters 24, 26, of the vacuum cleaner 1. This is because a high moving resistance of the brush 13 is indicative of a softer surface being cleaned, such as a textile carpet, and a lower moving resistance of the brush 13 is indicative of a harder surface being cleaned, such as a floor surface. Moreover, the moving resistance of the brush 13 affects the electrical quantities of electricity supplied to the electric brush motor 15. In this manner, the control arrangement 1 can separate between situations where the voltage Vm supplied to the electric motor 5 increases as a result of the current surface being cleaned, and situations in which the voltage Vm supplied to the electric motor 5 increases as a result of a clogged dust separation unit 22, and/or filters 24, 26, of the vacuum cleaner 1. Thus, in this manner, the control arrangement 21 is able to provide more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user-friendly vacuum cleaner 1. The moving resistance of the brush 13, as referred to herein, may also be referred to as a rolling resistance because the brush 13 according to the illustrated embodiments is configured to be rotated by the electric brush motor 15.

As explained above, according to some embodiments, the control arrangement 21 is configured to set a magnitude of the threshold limit Tl based on various aspects such as stored data on previous voltage levels Vm’ supplied to the electric motor 5, estimation of an operational condition of the vacuum cleaner 1 , estimation of whether the vacuum cleaner 1 is used for cleaning a soft or hard surface, estimation of a type of nozzle 11 being attached to the vacuum cleaner 1, one or more electrical quantities of electricity supplied to the electric brush motor 15, and the like. According to some embodiments, the control arrangement 21 may set a magnitude of the threshold limit Tl based on a combination of two or more of these aspects. Thereby, the control arrangement 21 can provide even more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user-friendly vacuum cleaner 1.

As mentioned above, according to the embodiments, illustrated in Fig. 1, the vacuum cleaner 1 comprises an output unit 7 in the form of a light emitting diode. According to further embodiments, the output unit 7 may comprise another type of device or arrangement for outputting a notification to a user upon request of the control arrangement 21 , such as another type of light emitting device, a display, a speaker, a summer, a communication device configured to send a notification to an external device, or the like.

Fig. 3 schematically illustrates a vacuum cleaner 1 according to some further embodiments. According to the illustrated embodiments, the vacuum cleaner 1 is a small sized hand-held vacuum cleaner. The vacuum cleaner 1 comprises an elongated body with a handle 2 at a first end 10 and a nozzle 11 arranged at a second end 10’ of the vacuum cleaner 1 , wherein the second end 10’ of the vacuum cleaner 1 is opposite to the first end 10. According to the embodiments illustrated in Fig. 3, the vacuum cleaner 1 is configured to be operated and supported using one hand on the handle 2 of the vacuum cleaner 1. The vacuum cleaner 1 comprises a fan 3 and an electric motor 5 configured to power, i.e. rotate, the fan 3. The fan 3 may comprise a centrifugal fan. The electric motor 5 may be a brushless or a brushed electric motor. The vacuum cleaner 1 comprises an airflow path 18 extending from an air inlet 14 of the vacuum cleaner 1 at the nozzle 11 to an air outlet 16 of the vacuum cleaner 1. The fan 3 is configured to generate an airflow through the airflow path 18 in a direction from the air inlet 14 towards the air outlet 16 during operation of the vacuum cleaner 1. According to the illustrated embodiments, the vacuum cleaner 1 comprises a dust separating unit 22 in the form of a filter 24. According to further embodiments, the vacuum cleaner 1 may comprise another type of dust separating unit 22, such as a dust bag, a centrifugal separator, or the like. The dust separating unit 22 is arranged in the airflow path 18 at a position upstream of the fan 3 and is configured to separate dust, and other types of particles and matter, from air flowing through the airflow path 18.

The vacuum cleaner 1 may comprise one or more further filter units such as for example a filter unit arranged in the airflow path 18 at a position between the fan 3 and the air outlet 16 of the vacuum cleaner 1, i.e. arranged at a position downstream of the fan 3 and upstream of the air outlet 16 of the vacuum cleaner 1. Apart from separating particles from the airflow, a further purpose of such a filter unit may be to attenuate noise generated by the vacuum cleaner 1 during operation thereof.

According to the illustrated embodiments, the vacuum cleaner 1 comprises a power source 9’ in the form of a battery 9 which is configured to supply electricity to the electric motor 5. According to further embodiments, the vacuum cleaner 1 may comprise a cord for connection to a socket connected to a power grid for providing electricity to the electric motor 5. The vacuum cleaner 1 further comprises a control arrangement 21 and an output unit 7. The control arrangement 21 is operably connected to the power source 9’, to the electric motor 5, and to the output unit 7. Moreover, the control arrangement 21 is operably connected to an actuator 27 of the vacuum cleaner 1 allowing activation and deactivation of the vacuum cleaner 1. According to the embodiments illustrated in Fig. 3, the actuator 27 is arranged in a region of the handle 2. Moreover, according to the illustrated embodiments, the battery 9 is configured to supply electricity to the electric motor 5 by an amount controlled by the control arrangement 21. Also in the embodiments illustrated in Fig. 3, the output unit 7 comprises a light emitting diode, i.e. a type of light emitting unit. According to further embodiments, the output unit 7 may comprise another type of device or arrangement for outputting a notification to a user upon request of the control arrangement 21 , such as another type of light emitting device, a display, a speaker, a summer, a communication device configured to send a notification to an external device, or the like.

Also in these embodiments, the control arrangement 21 is configured to monitor a quantity representative of an electric current Im supplied to the electric motor 5. Moreover, the control arrangement 21 is configured to increase a voltage Vm supplied to the electric motor 5 in response to a detected decrease in electric current Im supplied to the electric motor 5. The control arrangement 21 is further configured to output a notification via the output unit 7 if the voltage Vm supplied to the electric motor 5 exceeds a threshold limit during a first predetermined time t1, in the same manner as explained with reference to Fig. 1 and Fig. 2. That is, the vacuum cleaner 1 according to the embodiments illustrated in Fig. 3 may be operated in the same manner as explained with reference to Fig. 2. Therefore, below, simultaneous reference is made to Fig. 3 and Fig. 2, if not indicated otherwise. Moreover, the vacuum cleaner 1 according to the embodiments illustrated in Fig. 3 may comprise one or more of the features, functions, and advantages as the vacuum cleaner 1 explained with reference to Fig. 1 and Fig. 2. Therefore, these aspects are not further explained below.

The vacuum cleaner 1 according to the embodiments illustrated in Fig. 3 may be operated at power levels lower than the vacuum cleaner 1 explained with reference to Fig. 1. Lower power levels give relatively small pressure differences between air in the airflow path 18 and ambient air. However, since the control arrangement 21 is configured to output the notification based on the voltage Vm supplied to the electric motor 5, reliable notifications can be outputted despite the fact that the vacuum cleaner 1 is operating at lower power levels. In addition, the need for an unreliable mechanical pressure sensor is circumvented, as well as other types of devices or arrangements for indicating the clogging level of the dust separation unit 22 of the vacuum cleaner 1. In other words, a vacuum cleaner 1 is provided capable of indicating to a user of the vacuum cleaner 1 that it is time to empty a dust separation unit 22 in a simple, efficient, and accurate manner, while having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner.

Fig. 4 illustrates a vacuum cleaner 1 according to some further embodiments. According to the embodiments illustrated in Fig. 4, the vacuum cleaner 1 is robotic vacuum cleaner, i.e. a vacuum cleaner configured to navigate and operate an area without direct intervention or the direct control of a user. The vacuum cleaner 1 comprises an airflow path, a fan configured to generate an airflow through the airflow path, an electric motor configured to power the fan, a dust separating unit, and a battery configured to supply electricity to the electric motor. These components may comprise the same features and functions as the airflow path 18, the fan 3, the electric motor 5, the dust separating unit 22, and the battery 9 of the vacuum cleaner 1 explained with reference to Fig. 1 and Fig. 3 and have been omitted in Fig. 4 for reasons of brevity and clarity. Moreover, since the features and functions of these components already have been explained in detail above, they are not further explained below.

Apart from powering the electric motor for powering the fan, the battery of the vacuum cleaner 1 according to the embodiments illustrated in Fig. 4 may be configured to power one or more electric motors which each is configured to rotate a wheel of the vacuum cleaner 1. Thereby, the vacuum cleaner 1 can be navigated in an area without the intervention or the direct control of a user. According to the embodiments illustrated in Fig. 4, the vacuum cleaner 1 comprises two output units 7, 7’, in the form of a display 7 and a communication unit T. The features and functions of the display 7 and of the communication unit T are explained in more detail below. Moreover, according to further embodiments, the output unit 7 may comprise another type of device or arrangement for outputting a notification to a user, such as a light emitting diode, a light emitting device, a speaker, a summer, or the like.

The vacuum cleaner 1 further comprises a control arrangement 21. The control arrangement 21 may comprise the same features, functions, and advantages as the control arrangement 21 according to the embodiments explained with reference to Fig. 1 - Fig. 3. The control arrangement 21 is operably connected to the battery of the vacuum cleaner 1 , to the electric motor powering the fan, and to the output unit 7, T. The vacuum cleaner 1 according to the embodiments illustrated in Fig. 4 may be operated in the same manner as explained with reference to Fig. 2. Therefore, below, simultaneous reference is made to Fig. 2 and Fig. 4, if not indicated otherwise.

Also in these embodiments, the control arrangement 21 is configured to monitor a quantity representative of an electric current Im supplied to the electric motor powering the fan. Moreover, the control arrangement 21 is configured to increase a voltage Vm supplied to the electric motor powering the fan in response to a detected decrease in electric current Im supplied to the electric motor powering the fan. The control arrangement 21 is further configured to output a notification via the output unit 7, T if the voltage Vm supplied to the electric motor powering the fan exceeds a threshold limit Tl during a first predetermined time t1, in the same manner as explained with reference to Fig. 1 - Fig. 3. Moreover, the vacuum cleaner 1 according to the embodiments illustrated in Fig. 4 may comprise one or more of the features, functions, and advantages as the vacuum cleaner 1 explained with reference to Fig. 1 - Fig. 3. Therefore, these aspects are not further explained below. As mentioned above, according to the embodiments illustrated in Fig. 4, the vacuum cleaner 1 comprises two output units 7, 7’, in the form of a display 7 and a communication unit T.

The display 7 may for example output the notification by displaying a symbol, number, text, or the like. According to some embodiments of the herein described, the control arrangement 21 may be configured to estimate a clogging level of the airflow path and may calculate an estimated filling level of the dust separation unit of the vacuum cleaner 1 based on the voltage Vm supplied to the electric motor powering the fan of the vacuum cleaner 1. According to such embodiments, the control arrangement 21 may cause the output unit 7, 7’, such as the display 7, to output the notification in the form of a displaying of a number, text, or symbol indicative of the estimated filling level of the dust separation unit of the vacuum cleaner 1. In this manner, an even more user-friendly vacuum cleaner 1 is provided because the user can be informed about the estimated filling level of the dust separation unit before it is time to empty the dust separation unit.

In Fig. 4, an external device 40 is illustrated. The communication unit 7’ of the vacuum cleaner is configured to send the notification wirelessly to the external device 40. Thus, according to these embodiments, the control arrangement 21 of the vacuum cleaner 1 is configured to output the notification to the external device 40 via the communication unit 7’. The control arrangement 21 may also be configured to receive data from the external device 40 via the communication unit 7’, such as data comprising one or more instructions.

The communication unit 7’ may be configured to wirelessly transmit data to, and/or receive data from, the external device 40, via a remote wireless network router, for example a Wi-Fi router. The wireless communication may for example be performed over a wireless connection such as the internet, or a wireless local area network (WLAN), or a wireless connection for exchanging data over short distances using short-wavelength, i.e. ultra-high frequency (UHF) radio waves in the industrial, scientific and medical (ISM) band from 2.4 to 2.485 GHz. According to the illustrated embodiments, the external device 40 is a mobile phone, but may also be another type of device, such as a computer, a computer tablet, or the like. Moreover, according to some embodiments of the present disclosure, the control arrangement 21 may be configured to output a notification wirelessly via the communication unit 7’ to an external service centre or service centre personnel. The external device 40 may display the notification on a screen 42 thereof in the form of a symbol, number, text, or the like. Moreover, the notification may be displayed in the form of a number, text, or symbol indicative of the estimated filling level of the dust separation unit of the vacuum cleaner 1 as explained above. Features and functions of the vacuum cleaners explained with reference to Fig. 1 - Fig. 4 may be combined. That is, as an example, the vacuum cleaners 1 explained with reference to Fig. 1 and Fig. 3, may comprise an output unit 7, 7’ according to the embodiments explained with reference to Fig. 4.

In Fig. 4, a nozzle 11 of the vacuum cleaner 1 is indicated. According to the illustrated embodiments, the vacuum cleaner 1 comprises two brushes 13, 13’ arranged at the nozzle 11. Each of the brushes 13, 13’ are rotated by a respective electric brush motor 15, 15’. A first brush 13 of the two brushes 13, 13’ has a rotation axis substantially parallel to a floor surface when the vacuum cleaner 1 is positioned in an intended use position on the floor surface. A second brush 13’ of the two brushes 13, 13’ has a rotation axis transversal to a floor surface when the vacuum cleaner 1 is positioned in an intended use position on the floor surface. The rotation axis of the second brush 13’ may be substantially perpendicular to the floor surface when the vacuum cleaner 1 is positioned in an intended use position thereon. The first brush 13 may be referred to as a main brush and the second brush 13’ may be referred to as a side brush, sweep brush, or the like.

According to the embodiments illustrated in Fig. 4, the control arrangement 21 is configured to set a magnitude of threshold limit Tl based on one or more electrical quantities of electricity supplied to the respective electric brush motor 15, 15’. According to further embodiments, the control arrangement 21 may be configured to set a magnitude of threshold limit Tl based on one or more electrical quantities of electricity supplied to one of the two electric brush motors 15, 15’. The control arrangement 21 may be configured to set the threshold limit Tl to a higher value in case the one or more electrical quantities indicate a high moving resistance of a brush 13, 13’ and may be configured to set the threshold limit Tl to a lower value in case the one or more electrical quantities indicate a lower moving resistance of a brush 13, 13’. This is because a high moving resistance of the brush 13, 13’ is indicative of a softer surface being cleaned, such as a textile carpet, and a lower moving resistance of the brush 13, 13’ is indicative of a harder surface being cleaned, such as a non textile floor surface. Moreover, the moving resistance of the brush 13, 13’ affects the electrical quantities of electricity supplied to the electric brush motor 15, 15’. In this manner, the control arrangement 1 can separate between situations where the voltage Vm supplied to the electric motor for powering the fan increases as a result of the current surface being cleaned, and situations in which the voltage Vm supplied to the electric motor for powering the fan increases as a result of a clogged dust separation unit, and/or filters, of the vacuum cleaner 1. Thus, in this manner, the control arrangement 21 is able to provide a more accurate and reliable indication of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user-friendly vacuum cleaner 1. Moreover, according to the embodiments illustrated in Fig. 4, the vacuum cleaner 1 comprises an environment sensor 12. The environment sensor 12 is configured to provide data representative of a current environment in which the vacuum cleaner 1 operates. The environment sensor 12 may for example comprise an image capturing device, such as a camera, a light detection and ranging sensor arrangement, also referred to as a LIDAR sensor arrangement, or the like. According to these embodiments, the control arrangement 21 is configured to set a magnitude of the threshold limit Tl based on data from the environment sensor 12. The control arrangement 21 may be configured to set the threshold limit Tl to a higher value in case the data from the environment sensor 12 indicates that the vacuum cleaner 1 currently is operating a harder type of floor surface and may be configured to set the threshold limit Tl to a lower value in case the data from the environment sensor 12 indicates that the vacuum cleaner 1 currently is operating a softer type of floor surface, such as a textile carpet, or the like. In this manner, the control arrangement 21 is able to provide a more accurate and reliable indications of the clogging level of the vacuum cleaner 1 to a user which in turn provides a more user-friendly vacuum cleaner 1.

The vacuum cleaner 1 according to the embodiments illustrated in Fig. 4 may be operated at power levels lower than the vacuum cleaner 1 explained with reference to Fig. 1. Since the control arrangement 21 is configured to output the notification based on the voltage Vm supplied to the electric motor for powering the fan, the need for an unreliable mechanical pressure sensor is circumvented, as well as other types of devices or arrangements for indicating the clogging level of the dust separation unit of the vacuum cleaner 1. In other words, a vacuum cleaner 1 is provided capable of indicating to a user of the vacuum cleaner 1 that it is time to empty a dust separation unit of the vacuum cleaner 1 in a simple, efficient, and accurate manner, while having conditions and characteristics suitable for being manufactured and assembled in a cost-efficient manner. Moreover, since the output of the notification via the output unit 7, 7’ is based on the voltage supplied to the electric motor for powering the fan, a reliable notification can be outputted via the output unit 7, 7’ despite the fact that the vacuum cleaner 1 is operating at relatively low power levels which gives relatively small pressure differences between air in the airflow path of the vacuum cleaner 1 and ambient air.

Below, simultaneous reference is made to Fig. 1 - Fig. 4, if not indicated otherwise.

According to some embodiments, the control arrangement 21 comprises a control unit. One skilled in the art will appreciate that the control of the control arrangement 21 , such as the control of the power P of the electric motor 5 and the outputting of the notification, may be implemented by programmed instructions. These programmed instructions are typically constituted by a computer program, which, when it is executed in the control arrangement 21, ensures that the control arrangement 21 carries out the desired control. The computer program is usually part of a computer program product which comprises a suitable digital storage medium on which the computer program is stored.

The control arrangement 21 may be connected to one or more components of the vacuum cleaner 1. The control arrangement 21 may comprise a calculation unit which may take the form of substantially any suitable type of processor circuit or microcomputer, e.g. a circuit for digital signal processing (digital signal processor, DSP), a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “calculation unit” may represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones mentioned above.

The control arrangement 21 may further comprise a memory unit, wherein the calculation unit may be connected to the memory unit, which may provide the calculation unit with, for example, stored program code and/or stored data which the calculation unit may need to enable it to do calculations. The calculation unit may also be adapted to store partial or final results of calculations in the memory unit. The memory unit may comprise a physical device utilised to store data or programs, i.e. , sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory unit may comprise integrated circuits comprising silicon-based transistors. The memory unit may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

The wording “obtaining”, “obtain”, “setting”, and “set”, as used herein may comprise one or more calculations. As an alternative, or in addition, the wording “obtaining”, “obtain”, “setting”, and “set”, as used herein may comprise retrieving data from one or more tables, matrices, or the like. Therefore, throughout this disclosure, the wording “obtaining”, “obtain”, “setting”, and “set” may be replaced with the wording “calculate”, “calculating”, “retrieve” or “retrieving”.

The control arrangement 21 is connected to components of the vacuum cleaner 1 for receiving and/or sending input and output signals. These input and output signals may comprise waveforms, pulses, or other attributes which the input signal receiving devices can detect as information and which can be converted to signals processable by the control arrangement 21. These signals may then be supplied to the calculation unit. One or more output signal sending devices may be arranged to convert calculation results from the calculation unit to output signals for conveying to other parts of the control system of the vacuum cleaner 1 and/or the component or components for which the signals are intended. Each of the connections to the respective components of the vacuum cleaner 1 for receiving and sending input and output signals may take the form of one or more from among a cable, or a wireless connection.

In the embodiments illustrated, the vacuum cleaner 1 comprises a control arrangement 21 but might alternatively be implemented wholly or partly in two or more control arrangements or two or more control units. As an example, according to some embodiments, the electric motor 5 configured to power the fan 3 of the vacuum cleaner 1 may comprise one or more control arrangements and/or one more control units, which in such embodiments is/are comprised in the control arrangement 21 as referred to herein.

The computer program product may be provided for instance in the form of a data carrier carrying computer program code when being loaded into one or more calculation units of the control arrangement 21. The data carrier may be, e.g. a CD ROM disc, or a ROM (read-only memory), a PROM (programable read-only memory), an EPROM (erasable PROM), a flash memory, an EEPROM (electrically erasable PROM), a hard disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer program product may furthermore be provided as computer program code on a server and may be downloaded to the control arrangement 21 remotely, e.g., over an Internet or an intranet connection, or via other wired or wireless communication systems.

It is to be understood that the foregoing is illustrative of various example embodiments and that the invention is defined only by the appended independent claims. A person skilled in the art will realize that the example embodiments may be modified, and that different features of the example embodiments may be combined to create embodiments other than those described herein, without departing from the scope of the present invention, as defined by the appended independent claims.

As used herein, the term "comprising" or "comprises" is open-ended, and includes one or more stated features, elements, steps, components, or functions but does not preclude the presence or addition of one or more other features, elements, steps, components, functions, or groups thereof.

Claims

1. A vacuum cleaner (1) comprising: a fan (3), an electric motor (5) configured to power the fan (3), a control arrangement (21), and an output unit (7, 7’), wherein the control arrangement (21) is configured to monitor a quantity representative of an electric current (Im) supplied to the electric motor (5) and is configured to increase a voltage (Vm) supplied to the electric motor (5) in response to a detected decrease in electric current (Im) supplied to the electric motor (5), and wherein the control arrangement (21) is configured to output a notification via the output unit (7, 7’) if the voltage (Vm) supplied to the electric motor (5) exceeds a threshold limit (Tl) during a first predetermined time (t1).

2. The vacuum cleaner (1) according to claim 1 , wherein the vacuum cleaner (1) comprises a battery (9) configured to supply electricity to the electric motor (5) by an amount controlled by the control arrangement (21).

3. The vacuum cleaner (1) according to claim 1 or 2, wherein the control arrangement (21) is configured to control the voltage (Vm) supplied to the electric motor (5) by reducing the voltage supplied to the electric motor (5) from a power source (9’).

4. The vacuum cleaner (1) according to claim 2 and 3, wherein the control arrangement (21) is configured to input the voltage (Vm) supplied to the electric motor (5) by monitoring a current voltage (Vb) at the battery (9) and current voltage reduction data.

5. The vacuum cleaner (1) according to any one of the preceding claims, wherein the control arrangement (21) is configured to decrease the voltage (Vm) supplied to the electric motor (5) in response to a detected increase in electric current (Im) supplied to the electric motor (5).

6. The vacuum cleaner (1) according to any one of the preceding claims, wherein the control arrangement (21) is configured to regulate the voltage (Vm) supplied to the electric motor (5) to obtain a substantially constant power level (P) of the electric motor (5).

7. The vacuum cleaner (1) according to any one of the preceding claims, wherein the control arrangement (21) is configured to cancel the outputting of the notification if the voltage (Vm) supplied to the electric motor (5) declines below the threshold limit (Tl) during a second predetermined time (t2).

8. The vacuum cleaner (1) according to any one of the preceding claims, wherein the control arrangement (21) is configured to set a magnitude of the threshold limit (Tl) based on stored data on previous voltage levels (Vm’) supplied to the electric motor (5).

9. The vacuum cleaner (1) according to any one of the preceding claims, wherein the control arrangement (21) is configured to set a magnitude of the threshold limit (Tl) based on an estimation of an operational condition of the vacuum cleaner (1).

10. The vacuum cleaner (1) according to claim 9, wherein the estimation of the operational condition involves an estimation of whether the vacuum cleaner (1) is used for cleaning a soft or hard surface.

11. The vacuum cleaner (1) according to claim 9 or 10, wherein the estimation of the operational condition involves an estimation of a type of nozzle (11) being attached to the vacuum cleaner (1).

12. The vacuum cleaner (1) according to any one of the preceding claims, wherein the vacuum cleaner (1) comprises an environment sensor (12) configured to provide data representative of a current environment in which the vacuum cleaner (1) operates, and wherein the control arrangement (21) is configured to set a magnitude of the threshold limit (Tl) based on data from the environment sensor (12).

13. The vacuum cleaner (1) according to any one of the preceding claims, wherein the vacuum cleaner (1) comprises a nozzle (11), a brush (13, 13’) arranged at the nozzle (11), and an electric brush motor (15, 15’) configured to rotate the brush (13, 13’), and wherein the control arrangement (21) is configured to set the threshold limit (Tl) based on one or more electrical quantities of electricity supplied to the electric brush motor (15, 15’).

14. The vacuum cleaner (1) according to claim 13, wherein the control arrangement (21) is configured to set the threshold limit (Tl) to a higher value in case the one or more electrical quantities indicate a high moving resistance of the brush (13, 13’) and is configured to set the threshold limit (Tl) to a lower value in case the one or more electrical quantities indicate a lower moving resistance of the brush (13, 13’).

15. The vacuum cleaner (1) according to any one of the preceding claims, wherein the vacuum cleaner (1) is a hand-held vacuum cleaner, a stick-type vacuum cleaner, or a robotic vacuum cleaner.