METHOD FOR DETERMINING THE FILL LEVEL OF A DUST CONTAINER AND VACUUM CLEANER

Description

[0001] The invention relates to a method for determining the filling level of a dust container and to a vacuum cleaner.

[0002] When using vacuum cleaners, it is desirable to have information about the current fill level of the dust container, which temporarily stores the vacuumed dirt. This improves the user experience and facilitates planning the cleaning process.

[0003] In the prior art, two vacuum sensors are typically used for this purpose. In each case, a vacuum sensor is arranged upstream and downstream of the dust container along a suction path from a floor nozzle, through the dust container to a blower motor that provides a vacuum, i.e. in the area of ​​an inlet and an outlet of the dust container with reference to a direction of the volume flow towards the blower motor. As the fill level of the dust container increases, the hydraulic resistance of the dust container increases. As a result, the pressure difference between the two measuring points upstream and downstream of the dust container increases. The fill level of the dust container can then be determined from the knowledge of the correlation between the pressure difference and the fill level of the dust container.

[0004] In another version, the vacuum sensor downstream of the dust container is omitted. In this case, parameters of the fan motor are used to determine the vacuum downstream of the dust container.

[0005] However, both technical solutions in the prior art have the disadvantage of using one or even two vacuum sensors. These are cost-intensive, require additional hardware for connection, and have special design requirements. EP3120744 discloses a method for determining the fill level of a dust container of a vacuum cleaner according to the preamble of claim 1.

[0006] The invention therefore addresses the problem of determining the filling level of a dust container of a vacuum cleaner without the use of vacuum sensors.

[0007] The object is achieved in a first aspect by the method according to the invention according to claim 1. The object is also achieved in a second aspect by the vacuum cleaner according to the invention according to claim 15. Advantageous embodiments and further developments of the invention emerge from the following subclaims.

[0008] The object is achieved in the first aspect of the invention by the features of the method for determining a fill level of a dust container of a vacuum cleaner according to claim 1, wherein the vacuum cleaner comprises: a first suction section with a floor nozzle, a dust container, a second suction section, a blower motor configured to generate a negative pressure, wherein the floor nozzle, the first suction section, the dust container, the second suction section, and the blower motor form a suction path in this order and are fluidly coupled to one another such that air can be sucked in through the floor nozzle into the first suction section, the dust container, and the second suction section by the blower motor and is sucked in during operation, wherein the method comprises the following steps: Measuring at least one motor characteristic number of the blower motor as a function of time, determining a first parameter from the motor characteristic number, wherein the first parameter correlates with a volume flow and / or negative pressure in the second suction section or is a volume flow or negative pressure in the second suction section, determining a second parameter, wherein the second parameter correlates with a volume flow and / or negative pressure at the floor nozzle or is a volume flow or negative pressure at the floor nozzle, and determining a filling level of the dust container from the first parameter and the second parameter.

[0009] In the context of the invention, a dust container describes a component in which dust is separated from the air flow during vacuuming and is temporarily stored until the dust container is cleaned or emptied.

[0010] The dust container can, for example, be bagless. In this case, the dust container can be designed as a closed chamber with an inlet through which the airflow enters the dust container during suction, and an outlet from which the airflow exits toward the fan motor. A bagless dust container can, for example, be designed as a centrifugal or cyclone separator. For emptying, the dust container can be opened, and the dirt inside can be removed.

[0011] The dust container can also be designed to accommodate a disposable or reusable bag. In this case, the airflow can be directed through the disposable or reusable bag during suction. Due to its design, the disposable or reusable bag can act like a filter, trapping the dirt sucked in with the airflow within the disposable or reusable bag. For emptying, the disposable bag can be removed and disposed of, and replaced with a new disposable bag. Alternatively, the reusable bag can be cleaned and reinserted into the dust container for emptying.

[0012] In the context of the invention, the fill level of the dust container describes a measure of the amount of dirt contained in the dust container. The fill level can range from "empty," in which there is no or negligible amount of dirt in the dust container, to "fully full," in which the maximum amount of dirt is present. In the "fully full" state, for example, the vacuum cleaner can no longer reliably perform its proper cleaning function.

[0013] The blower motor, in the sense of the invention, is an electric motor comprising an inlet and an outlet. The blower motor is configured to draw in or suck in air at the inlet, i.e., to create a negative pressure at the inlet and discharge the drawn-in air at the outlet. In the case of the invention, the blower motor draws air through the floor nozzle through the suction path toward its inlet and discharges the drawn-in air into the environment of the vacuum cleaner. In other words, the blower motor applies a negative pressure to the suction path. As a result of the negative pressure, an air flow or volume flow is created through the suction path toward the blower motor.

[0014] Within the scope of the invention, the first suction section describes the structural transition from the floor nozzle to the dust container. Within the scope of the invention, the second suction section describes the structural transition from the dust container to the blower motor.

[0015] Within the scope of the invention, the floor nozzle describes an element with an opening that forms the entrance to the suction path consisting of the floor nozzle, first suction section, dust container, second suction section, and blower motor. During operation or use of the vacuum cleaner, i.e., when the blower motor is vacuuming, air enters the suction path through the opening of the floor nozzle. During operation, the floor nozzle is in contact or engagement with, for example, a floor covering.

[0016] The design of the floor nozzle, together with the nature of the floor covering, determines the hydraulic resistance at the floor nozzle when the vacuum cleaner is in use. The floor covering has a significant influence on the hydraulic resistance: for example, a deep-pile carpet has a higher contribution to the hydraulic resistance at the floor nozzle than a hard floor. This results from the fact that, depending on the pile height, the pile of the carpet can be sucked into the floor nozzle when it comes into contact with the floor nozzle. This reduces the opening of the floor nozzle, making it more difficult to suck in air. In addition, the hydraulic resistance is undefined due to the uncontrolled suction of the pile into and in the opening of the floor nozzle. A hard floor, in comparison, has a defined distance from the floor nozzle. This results in a consistently defined opening of the floor nozzle.Typical examples of hard floors include parquet, laminate, floorboards, tiles, PVC flooring, and concrete. Very low-pile carpets can also have similar properties to hard floors and are also considered a hard floor.

[0017] For the purposes of the invention, a blower motor characteristic is any measurable or derivable variable that is suitable for characterizing the current operating state of the blower motor. Typical examples include the following variables: speed of the blower motor, voltage applied to the blower motor, current consumed by the blower motor, and power consumed by the blower motor.

[0018] The first parameter correlates with a volume flow and / or negative pressure in the second suction section. Alternatively, the first parameter is a volume flow or a negative pressure in the second suction section.

[0019] The second parameter correlates with a volume flow and / or negative pressure at the floor nozzle. Alternatively, the second parameter is a volume flow or a negative pressure at the floor nozzle.

[0020] The vacuum cleaner can additionally comprise a control unit. The control unit can, for example, comprise a microcontroller or microprocessor and a data memory. The control unit can be configured and designed to carry out all steps of the method according to the invention. In particular, the control unit can be configured and designed to determine the first and second parameters as well as the fill level. In addition, the control unit can be configured and designed to measure the at least one motor characteristic value of the blower motor.

[0021] The method according to the invention has the advantage that it does not require a vacuum sensor. Only components already present in the vacuum cleaner are used to determine the vacuum before and after the dust container. The method according to the invention thus enables a more cost-effective and simpler design of the vacuum cleaner according to the invention. Furthermore, the method simplifies the measurement of the dust container's fill level.

[0022] According to the first aspect of the invention, the second parameter is determined from the hydraulic resistance at the floor nozzle, a detected floor surface and the first parameter.

[0023] The floor surface can be detected, for example, using a suitable sensor in the floor nozzle. This sensor can distinguish between a carpet and a hard floor with which the floor nozzle comes into contact.

[0024] The detected floor surface influences the determination of the second parameter in such a way that the second parameter can only be determined if a hard floor is detected. If a carpet, especially a deep-pile carpet, is detected, the opening on the floor nozzle and thus the hydraulic resistance at the floor nozzle during operation of the vacuum cleaner cannot be clearly defined. The second parameter cannot be determined in this case.

[0025] In other words, the second parameter can be determined from the hydraulic resistance at the floor nozzle and the first parameter if a hard floor is detected at the floor nozzle. This allows for a technically simple determination of the second parameter.

[0026] In a preferred embodiment according to the first aspect of the invention, the first parameter is determined from the motor characteristic number and a pressure characteristic curve that correlates the motor characteristic number with the negative pressure and / or volume flow in the second suction section, wherein the second parameter is determined from the hydraulic resistance at the floor nozzle, a detected floor surface and the negative pressure and / or volume flow in the second suction section.

[0027] For the purposes of the invention, a pressure characteristic curve is a relationship between two physical quantities in which each value of an engine characteristic is assigned a negative pressure value. Alternatively, a pressure characteristic curve is a characteristic curve that assigns a volume flow to each value of an engine characteristic.

[0028] Using the pressure characteristic curve, a technically simple determination of the first parameter is possible.

[0029] In a preferred embodiment according to the first aspect of the invention, the degree of filling of the dust container is determined from the volume flow at the floor nozzle and the volume flow in the second suction section or the negative pressure at the floor nozzle and the negative pressure in the second suction section.

[0030] This represents a technically simple and implementable option with little technical effort to determine the filling level of the dust container with high accuracy.

[0031] In a preferred embodiment according to the first aspect of the invention, the motor characteristic comprises one or more of the following characteristics: speed of the fan motor, voltage applied to the fan motor, current consumed by the fan motor, power consumed by the fan motor.

[0032] These parameters can be determined with little technical effort and high accuracy and are therefore particularly suitable as engine parameters in the method according to the invention.

[0033] In a preferred embodiment according to the first aspect of the invention, the degree of filling of the dust container is determined on the basis of a filling level characteristic curve which correlates the degree of filling of the dust container with the first parameter and the second parameter.

[0034] For the purposes of the invention, a fill level characteristic curve is a relationship between two physical variables, in which each value of the first and second parameters is assigned a value for the fill level of the dust container. It is also conceivable that a value calculated or derived from the first and second parameters is assigned a fill level of the dust container.

[0035] The first and second parameters, as well as the variables calculated or derived from the first and second parameters, can be referred to as the input variables of the fill level characteristic. The fill level of the dust container can be referred to as the output variable of the fill level characteristic.

[0036] Examples of a quantity calculated or derived from the first and second parameters are the difference between the first and second parameters or the difference between the second and first parameters, the quotient of the first and second parameters or the quotient of the second and first parameters or any other suitable mathematical function that has the first and second parameters as arguments.

[0037] The fill level curve can depend on the specific design of the vacuum cleaner, especially the dust container. A fill level curve must therefore be determined individually for each vacuum cleaner model in advance, e.g., during production.

[0038] A fill level curve thus offers the possibility of determining the fill level of the dust container with high accuracy. Furthermore, the fill level can be determined using simple technical means without complex calculations.

[0039] In a preferred embodiment according to the first aspect of the invention, the dust container is designed to receive a disposable or reusable bag and the fill level characteristic describes a first characteristic.

[0040] A first characteristic can, for example, be a linearly increasing behavior of the fill level curve. In other words, the first characteristic can describe a mathematical function that correlates the input variable(s) of the fill level curve with the fill level of the dust bag, for example, via a linear relationship.

[0041] This characteristic is particularly advantageous because it allows statements about the filling level of the dust bag to be made with high accuracy.

[0042] In a preferred embodiment according to the first aspect of the invention, the dust container is bagless and the fill level characteristic describes a second characteristic.

[0043] Bagless vacuum cleaners, for example, can implement the principle of a centrifugal separator, also known as a cyclone separator. The airflow entering the typically cylindrical or conical dust container is introduced tangentially and directed into a circular path. Due to collisions with the walls of the dust container during the circular motion, the sucked-in dirt particles lose their kinetic energy and fall into a dirt collection area. The dirt-free air then leaves the dust container through a corresponding outlet.

[0044] If the volume in the dust container becomes too small to maintain the orderly circular path of the airflow due to a filling level close to the "maximum filling" state, the airflow transitions into a disordered, non-circular airflow. As a result, the separation of dirt from the intake air is interrupted. This process can occur largely abruptly, i.e., suddenly, and can manifest itself in a sudden change in at least one measured motor characteristic and at least the first parameter determined from it. For example, the power consumed by the fan motor can decrease abruptly.

[0045] A second characteristic can therefore be any sudden, sharp increase in the fill level curve. For example, the second characteristic can describe a mathematical function that correlates the input variable(s) of the fill level curve with the fill level of the dust bag via a relationship that can be approximated, for example, using an exponential or logarithmic function.

[0046] This characteristic is particularly well suited to provide information about the filling level, in particular the maximum filling level of the dust container, with high accuracy.

[0047] In a preferred embodiment according to the first aspect of the invention, when the disposable or reusable bag is changed or the bagless dust container is emptied, the filling level of the dust container is manually or automatically set to zero.

[0048] For example, when opening or closing the dust container, e.g., to change the disposable or reusable bag or to empty the dust container, a button, switch, or sensor can be activated, which informs the control unit that the dust container has been emptied and the fill level is now in the "empty" state, i.e., has been set to zero. It is also conceivable for a user to reset the level manually, e.g., by pressing an input device on the vacuum cleaner.

[0049] The control unit can thus receive an indication of a defined state, the "empty" state, and does not have to determine this through measurements and parameter determinations. This allows the control unit to receive an indication of a defined position in the fill level characteristic curve, thereby improving the accuracy and technical feasibility of the method according to the invention.

[0050] In a preferred embodiment according to the first aspect of the invention, the method for determining the degree of filling of the dust container is paused when a change in the contact of the floor nozzle from a hard floor to a carpet is detected and / or the method for determining the degree of filling of the dust container is continued when a change in the contact of the floor nozzle from a carpet to a hard floor is detected.

[0051] Preferably, pausing and / or continuing the process for determining the fill level of the dust container occurs automatically.

[0052] In the sense of the invention, a change in the contact of the floor nozzle from a hard floor to a carpet describes the change in the contact or engagement of the floor nozzle from a hard floor to a carpet.

[0053] Pausing the execution of the process for determining the dust container fill level can be considered an interruption of the process for later resumption, i.e., continuation. In this case, all values ​​and parameters determined so far, in particular the dust container fill level, can be stored in a data memory of the control unit.

[0054] Pausing the execution of the method can also be considered an abort. In this case, the method can be restarted, i.e., continued, upon detecting a change in the contact of the floor nozzle from a carpet to a hard floor. The method is then restarted by measuring at least one motor characteristic of the blower motor and the subsequent steps according to the invention. The fill level of the dust container can then be determined using the fill level characteristic curve.

[0055] The interruption and continuation of the method according to the invention when moving from a hard floor to a carpet and vice versa has the advantage that the accuracy of determining the degree of filling of the dust container is improved, since no reliable statement can be made about the filling level of the dust container when in contact with a carpet.

[0056] In a preferred embodiment according to the first aspect of the invention, the change of contact of the floor nozzle from a hard floor to a carpet or from a carpet to a hard floor is detected by a floor covering detection device.

[0057] The floor covering detection device is preferably incorporated into the floor nozzle and detects the floor covering while the vacuum cleaner is in use. Detection of the floor covering can be achieved, for example, using optical sensors, such as a camera.

[0058] The floor covering detection device enables efficient detection of the floor covering.

[0059] In a preferred embodiment according to the first aspect of the invention, the change of contact of the floor nozzle from a hard floor to a carpet is detected by the following steps: Detecting an abrupt change in the blower motor characteristic and / or the first parameter, comparing the abrupt change with the previously known characteristic curve and / or the dust container fill level, and detecting a transition from hard floor to carpet if the detected abrupt change does not correlate with a maximum dust container fill level.

[0060] This represents an alternative way of detecting the change of contact of the floor nozzle without the need for a floor covering detection device.

[0061] In a preferred embodiment according to the first aspect of the invention, upon detection of a maximum filling level of the dust container, a user is given an indication, wherein the giving of the indication comprises one or more of the following indication means: actuation of an optical means, actuation of an acoustic means and / or reduction of the power of the blower motor.

[0062] An example of a visual device could be a light-emitting diode or a display. An example of an acoustic device could be a spoken message, a signal tone, or a sequence of signal tones.

[0063] Displaying a warning is a simple and effective way to alert the user that the dust container is full. Furthermore, reducing the fan motor's power can not only alert the user that the dust container is full, but also prevent damage to the vacuum cleaner, such as overheating, if the user ignores the visual or audible warning.

[0064] In a preferred embodiment according to the first aspect of the invention, the indications are given by different indication means in temporal succession.

[0065] In this context, sequential means that a first clue is given at a first point in time and a second clue is given at a second point in time, with the second point in time being after the first point in time.

[0066] For example, a visual device, such as a display or an LED, can be activated at a first point in time. At a second point in time, the power of the fan motor can then be reduced.

[0067] This provides a simple and effective way to alert users when the dust container is full. It also allows for simple and effective protection of the vacuum cleaner.

[0068] The object is achieved in the second aspect of the invention by the features of the vacuum cleaner according to claim 15, wherein the vacuum cleaner comprises: a first suction section with a floor nozzle, a dust container, a second suction section, a blower motor which is configured to generate a negative pressure, wherein the floor nozzle, the first suction section, the dust container, the second suction section and the blower motor form a suction path with one another in this order and are fluidly coupled such that air can be sucked in by the blower motor through the floor nozzle into the first suction section, the dust container and the second suction section, wherein the vacuum cleaner is a bagless vacuum cleaner or a vacuum cleaner which is configured to receive a disposable or reusable bag, wherein the vacuum cleaner is configured to carry out the inventive method according to claims 1 to 14.

[0069] The statements made regarding the vacuum cleaner in the context of the first aspect of the invention also apply to the vacuum cleaner according to the second aspect of the invention. To avoid unnecessary redundancy, they will therefore not be repeated here and reference is made to the relevant previous sections.

[0070] It should be clarified that one or more of the preferred embodiments described above, as long as they are consistent, can be combined with one another and also represent preferred embodiments.

[0071] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. Figure 1 shows a schematic representation of an embodiment of a vacuum cleaner according to the invention, Figure 2 shows a schematic representation of an example of a suction path in a vacuum cleaner according to the invention, Figure 3 shows an example of a fill level characteristic curve with a first characteristic, and Figure 4 shows an example of a fill level characteristic curve with a second characteristic.

[0072] Figure 1 shows a schematic representation of an embodiment of a vacuum cleaner 1 according to the invention. Figure 2 shows a schematic representation of a suction path 2 in a vacuum cleaner 1 according to the invention.

[0073] The vacuum cleaner 1 comprises a first suction section 5 with a floor nozzle 3, a dust container 7, a second suction section 9, and a blower motor 11 that is configured to generate a negative pressure. The floor nozzle 3, the first suction section 5, the dust container 7, the second suction section 9, and the blower motor 11 form a suction path 2 in this order and are fluidly coupled to one another in such a way that air can be sucked in through the floor nozzle 3 into the first suction section 5, the dust container 7, and the second suction section 9 by the blower motor 11 and is sucked in during operation of the vacuum cleaner 1. The vacuum cleaner 1 is a bagless vacuum cleaner or a vacuum cleaner 1 configured to accommodate a disposable or reusable bag. The vacuum cleaner 1 is configured to carry out the method according to the invention for determining the fill level of a dust container 7 of the vacuum cleaner 1.

[0074] The first suction section 5 describes in the context of the invention the transition from the floor nozzle 3 to the dust container 7. In Fig. 1 The first suction section is shown as a suction hose. The second suction section 9 describes, within the scope of the invention, the transition from the dust container 7 to the blower motor 11. Fig. 2 The second suction section is shown as an example connecting piece.

[0075] The method for determining the filling level of the dust container 7 of the vacuum cleaner 1 comprises the following steps: Measuring at least one motor characteristic number of the blower motor 11 as a function of time, determining a first parameter from the motor characteristic number, wherein the first parameter correlates with a volume flow and / or negative pressure in the second suction section 9 or is a volume flow or negative pressure in the second suction section 9, determining a second parameter, wherein the second parameter correlates with a volume flow and / or negative pressure at the floor nozzle 3 or is a volume flow or negative pressure at the floor nozzle 3, and determining a filling level of the dust container 7 from the first parameter and the second parameter.

[0076] The vacuum cleaner 1 additionally comprises a control unit (not shown). The control unit can, for example, comprise a microcontroller or microprocessor and a data memory. The control unit can be configured and designed to carry out all steps of the method according to the invention.

[0077] The floor nozzle 3 has an opening 13, which forms the entrance to the suction path 2 from the floor nozzle 3 - first suction section 5, which is Figure 1 shown as a hose by way of example - dust container 7 - second suction section 9 - and blower motor 11. Air thus enters the suction path 2 through the opening 13 of the floor nozzle 3 during operation or use of the vacuum cleaner 1, ie when the blower motor 11 is vacuuming. The air flow, ie the volume flow V of the air, is in Fig. 2 shown. During operation, the floor nozzle 3 is in contact or engagement, for example, with the floor 15 or the floor covering of the floor 15.

[0078] The structural design of the floor nozzle 3 determines a hydraulic resistance at the floor nozzle 3 when the floor nozzle 3 is used during use of the vacuum cleaner 1, together with the nature of the floor covering of the floor 15.

[0079] The floor nozzle 3 has a floor covering detection device 17. The floor covering detection device allows automatic detection of whether the floor nozzle 3 is in contact with a hard floor or a carpet, e.g., a deep-pile carpet. Based on the detected floor covering, the process for determining the fill level of the dust container 7 can then be paused or continued, for example.

[0080] If, in the method according to the invention, the fill level of the dust container 7 is determined to be "maximally full" or, alternatively, filled to a predetermined level, a user is given a notification by means of the notification means 19 in the form of an LED. Additionally or alternatively, an acoustic notification can also be used and / or the power of the fan motor 11 can be reduced. An example of an acoustic notification can be a spoken notification text, a signal tone, or a sequence of signal tones.

[0081] Figures 3 and 4 Each shows an example of a fill level characteristic curve 21a and 21b with a first characteristic 23a and a second characteristic 23b, respectively. The fill level characteristic curve is shown as the fill level of the dust container 7 on the y-axis 25 as an example depending on a differential pressure, i.e., the difference in the negative pressure in the second section (first parameter) and at the floor nozzle (second parameter), on the x-axis 27. The value on the y-axis corresponding to the "maximally full" state is shown as a horizontal dashed limit line 29.

[0082] The first characteristic 23a shows, by way of example, a fill level on the y-axis 25 of the dust container 7 of the vacuum cleaner 1 that increases linearly with increasing differential pressure on the x-axis 27. This can be an example of a first characteristic of a fill level characteristic curve of a vacuum cleaner 1 with a disposable or reusable bag.

[0083] The second characteristic 23b shows, by way of example, a fill level on the y-axis 25 increasing while the differential pressure on the x-axis 27 remains low. Shortly before reaching the "maximally filled" state, represented by the limit line 29, the differential pressure on the x-axis 27 increases sharply. This can be an example of a second characteristic of a fill level curve of a bagless vacuum cleaner 1. In this case, the abrupt increase in the differential pressure can be explained by a collapse of the pressure in the dust container 7.

Claims

1. Method for determining a fill level of a dust container (7) of a vacuum cleaner (1), the vacuum cleaner (1) comprising: a first suction portion (5) having a floor nozzle (3), a dust container (7), a second suction portion (9), a fan motor (11) which is designed to generate a negative pressure, the floor nozzle (3), the first suction portion (5), the dust container (7), the second suction portion (9) and the fan motor (11) in this order forming a suction path (2) and being fluidly coupled to one another in such a way that air can be and is sucked in by the fan motor (11) through the floor nozzle (3) into the first suction portion (5), the dust container (7) and the second suction portion (9), the method comprising the following steps: - measuring at least one motor characteristic of the fan motor (11) as a function of time, - determining a first parameter from the motor characteristic, the first parameter correlating with a volume flow and / or negative pressure in the second suction portion (9) or being a volume flow or negative pressure in the second suction portion (9), - determining a second parameter, the second parameter correlating with a volume flow and / or negative pressure at the floor nozzle (3) or being a volume flow or negative pressure at the floor nozzle (3), - determining a degree of filling of the dust container (7) from the first parameter and the second parameter, characterised in that the second parameter is determined from the hydraulic resistance at the floor nozzle (3), a detected floor surface and the first parameter.

2. Method according to claim 1, wherein the first parameter is determined from the motor characteristic and a pressure characteristic curve which correlates the motor characteristic with the negative pressure and / or volume flow in the second suction portion (9), wherein the second parameter is determined from the hydraulic resistance at the floor nozzle (3), a detected floor surface and the negative pressure and / or volume flow in the second suction portion (9).

3. Method according to any of claims 1 to 2, wherein the degree of filling of the dust container (7) is determined from the volume flow at the floor nozzle (3) and the volume flow in the second suction portion or the negative pressure at the floor nozzle (3) and the negative pressure in the second suction portion (9).

4. Method according to any of claims 1 to 3, wherein the motor characteristic comprises one or more of the following characteristic variables: speed of the fan motor (11), voltage applied to the fan motor (11), current consumed by the fan motor (11), power consumed by the fan motor (11).

5. Method according to any of claims 1 to 4, wherein the degree of filling of the dust container (7) is determined on the basis of a fill level characteristic curve (21a, 21b) which correlates the degree of filling of the dust container (7) with the first parameter and the second parameter.

6. Method according to any of claims 1 to 5, wherein the dust container (7) is designed to receive a disposable or reusable bag and the fill level characteristic curve (21a, 21b) describes a first characteristic (23a).

7. Method according to any of claims 1 to 5, wherein the dust container (7) is bagless and the fill level characteristic curve (21a, 21b) describes a second characteristic (23b).

8. Method according to any of claims 1 to 7, wherein, when changing the disposable or reusable bag or emptying the bagless dust container (7), the degree of filling of the dust container (7) is manually or automatically set to zero.

9. Method according to any of claims 1 to 8, wherein the method for determining the fill level of the dust container (7) is paused when a change in the contact of the floor nozzle (3) from a hard floor to a carpet is detected and / or the method for determining the fill level of the dust container (7) is continued when a change in the contact of the floor nozzle (3) from a carpet to a hard floor is detected.

10. Method according to claim 9, wherein the change in the contact of the floor nozzle (3) from the hard floor to a carpet or from a carpet to a hard floor is detected by a device for floor covering detection (17).

11. Method according to claim 9, wherein the change in the contact of the floor nozzle (3) from a hard floor to a carpet is detected by the following steps: - detecting an abrupt change in the motor characteristic of the fan motor (11) and / or the first parameter, - comparing the abrupt change with the previously known characteristic curve and / or the fill level of the dust container (7), - detecting a transition from hard floor to carpet if the abrupt change detected does not correlate with a maximum fill level of the dust container (7).

12. Method according to any of claims 1 to 11, wherein a user is notified when a maximum fill level of the dust container (7) is detected, wherein giving the notification comprises one or more of the following notification means (19): actuation of an optical means, actuation of an acoustic means and / or reduction of the power of the fan motor (11).

13. Method according to claim 12, wherein the notifications are given by different notification means (19) one after the other.

14. Vacuum cleaner (1), comprising a first suction portion (5) having a floor nozzle (3), a dust container (7), a second suction portion (9), a fan motor (11) which is designed to generate a negative pressure, wherein the floor nozzle (3), the first suction portion (5), the dust container (7), the second suction portion (9) and the fan motor (11) in this order form a suction path (2) and are fluidly coupled to one another in such a way that air can be sucked in by the fan motor (11) through the floor nozzle (3) into the first suction portion (5), the dust container (7) and the second suction portion (9), wherein the vacuum cleaner (1) is a bagless vacuum cleaner (1) or a vacuum cleaner (1) which is designed to receive a disposable or reusable bag, wherein the vacuum cleaner (1) is designed to carry out the method according to claims 1 to 13.