Vacuum cleaner, preferably hand vacuum cleaner

Abstract

The invention relates to a vacuum cleaner (1), preferably a handheld vacuum cleaner (1), comprising a blower (12) with an impeller for generating an airflow, a first electric motor (12a) for driving the impeller of the blower (12), a suction nozzle (14) with a rotatable brush (15), a second electric motor (15a) for driving the rotatable brush (15), and a control unit (17) which is designed and configured to operate at least the first electric motor (12a) and / or the second electric motor (15a). The vacuum cleaner (1) is characterized in that the control unit (17) is designed and configured to detect an impermissibly high load on the first electric motor (12a) and / or the second electric motor (15a) and, in response, to switch the operation of the second electric motor (15a) from a first direction of rotation to a second direction of rotation.

Description

[0001] The invention relates to a vacuum cleaner, preferably a handheld vacuum cleaner, according to the preamble of patent claim 1.

[0002] Vacuum cleaners are cleaning devices that suck in air and dirt from a surface and then expel the air, at least largely purified of dirt, back outside. Such vacuum cleaners can be operated by connecting it to a power outlet via a cable. However, it can be more convenient for the user not to have to worry about the cable while vacuuming, which is why cordless vacuum cleaners are also well-known and widespread. These use a battery or accumulator as a rechargeable electrical energy storage device. In particular, the comparatively compact and lightweight handheld vacuum cleaners are often battery-operated to make them quicker and easier for the user to use.

[0003] A vacuum cleaner has a fan that can generate the airflow. This can create a negative pressure on the intake side of the fan, which can cause air to flow inward; this section of the vacuum cleaner can also be referred to as the vacuum zone.

[0004] On the side opposite the fan, towards which the airflow is directed, there is usually at least one filter or filter system through which the airflow is passed. This section of the vacuum cleaner can also be referred to as the vacuum cleaner's overpressure zone. The filter can trap dirt such as dust, particularly house dust, as well as other smaller particles from the airflow and thereby filter the airflow, which then leaves the vacuum cleaner cleaner than when it was sucked in. This allows the dirt to be cleaned from the surface. The surface can be any surface, such as a floor or its floor covering.

[0005] Depending on the design of the vacuum cleaner, the airflow and dirt can be directed directly via a suction nozzle, which acts as an intake opening and is a component of the vacuum cleaner itself. The suction nozzle, which can also be referred to as a floor nozzle, can also be connected to the vacuum cleaner via a suction hose and, if necessary, an additional telescopic tube. In this case, the vacuum cleaner and the other components, such as the suction nozzle, suction hose, and, if necessary, the telescopic tube, can be referred to as a vacuum cleaner system. In either case, the suction nozzle can be guided by a user over a surface to collect dirt with the sucked-in air.

[0006] To improve the cleaning effect, a brush can be installed near the suction nozzle. This brush can be driven in a rotating manner to brush the surface to be cleaned, loosening dirt from the fibers of a carpet, for example, so that the loosened dirt can be more effectively carried away by the airflow. This can improve the cleaning effect of the vacuum cleaner. This brush can also be called a floor brush or a brush roller.

[0007] The fan of such vacuum cleaners is typically powered by a first electric motor. Brushless electric motors are often used for this purpose, as they do not have slip rings or commutators and brushes between the rotor and stator, which can wear out. Therefore, brushless electric motors typically have a longer service life than brushed motors. This can have a correspondingly positive effect on the service life of the vacuum cleaner. Brushless electric motors also typically have higher performance than brushed motors.

[0008] The floor brush can also be operated with a second electric motor, which, however, is usually designed with brushes, i.e. as a brushed electric motor, for cost reasons.

[0009] With regard to the operation or rotation of the floor brush or its second electric motor, it should be noted that floor brushes are usually operated with a defined, fixed direction of rotation, i.e. they are always driven in the same direction during operation. The surface or floor covering to be cleaned usually influences the operation of the second electric motor, since the load on the second electric motor is significantly influenced by the surface with which the rotating floor brush is in contact. A smooth surface such as tiles or a short-haired carpet represents a lower load for the rotating floor brush or its second electric motor than a comparatively normal-length or long-haired carpet, which can offer considerable mechanical resistance to the rotational movement of the rotating floor brush or its second electric motor.

[0010] If the vacuum cleaner or its control unit can detect this, it can shut down the second electric motor for the safety of the floor brush if the load becomes too great for the second electric motor. In this case, the floor brush is not available for cleaning the surface, such as a normal-length, long-hair, or high-pile carpet.

[0011] This applies similarly to the first electric motor of the blower, as the surface can also affect the airflow. Thus, the achievable negative pressure for sucking in dirt and the like, which can be generated by the blower or its first electric motor, can also depend on the surface to be cleaned. Finally, a comparatively normal-length or long-haired carpet can act as a seal on the suction opening of the floor brush and thus significantly counteract the airflow generated by the blower or its first electric motor. This is also not the case or is significantly less the case with a smooth surface such as tile flooring or with a short-haired carpet.

[0012] EP 1 371 317 A2 describes a vacuum cleaner with a canister assembly having a collection container, with a suction generator, with a nozzle assembly, wherein the nozzle assembly comprises a housing defining an agitator cavity and an agitator mounted in the agitator cavity for rotation (a) in a first direction for pulling the nozzle assembly forward and (b) in a second direction for pulling the nozzle assembly backward, with a drive motor for driving the agitator, and with an actuator for controlling the operation of the drive motor and the direction of rotation of the agitator. The forward pulling of the nozzle assembly and the backward pulling of the nozzle assembly by the user can be detected by a push-and-pull handle of the vacuum cleaner by actuating a switch on the handle when the user pushes or pulls the vacuum cleaner, respectively.Accordingly, the agitator can be rotated in the detected direction of movement to support the user's desired movement.

[0013] EP 2245974 A2 describes a method for operating an attachment for a vacuum cleaner, wherein the attachment comprises an electrically rotatable bristle roller and a motor for driving the bristle roller, and wherein the bristle roller is rotated in an operating direction of rotation during operation, wherein the bristle roller is rotated in a direction of rotation opposite to the operating direction of rotation - reverse direction of rotation - if a blockage of the bristle roller is detected.

[0014] EP 1656874 A2 describes a vacuum cleaner with an electric motor for driving a floor brush and a temperature sensor for detecting a temperature of the electric motor, wherein the electric motor is stopped when the temperature of the electric motor rises above a predetermined temperature value.

[0015] EP 3970584 A1 describes a vacuum cleaner with a first electric motor for driving the impeller of the fan, with a suction nozzle with a rotatable brush, and with a second electric motor for driving the rotatable brush. The vacuum cleaner is designed to operate the second electric motor in a speed-controlled manner at a predetermined target speed, and the control unit is designed to operate the first electric motor. The invention thus addresses the problem of providing a vacuum cleaner whose floor brush can be operated continuously and / or as effectively as possible, preferably even with relatively long-haired carpets. This should preferably be achieved in the simplest, most cost-effective, space-saving, and / or energy-saving manner possible. This should preferably be implemented for battery-operated vacuum cleaners. At the very least, an alternative to known vacuum cleaners of this type should be created.

[0016] According to the invention, this problem is solved by a vacuum cleaner having the features of patent claim 1. Advantageous embodiments and further developments of the invention emerge from the following subclaims.

[0017] The invention thus relates to a vacuum cleaner, preferably a handheld vacuum cleaner, having a fan with an impeller for generating an air flow, having a first electric motor for driving the impeller of the fan, having a suction nozzle with a rotatable brush, having a second electric motor for driving the rotatable brush and having a control unit which is designed and configured to operate at least the first electric motor and / or the second electric motor.

[0018] The vacuum cleaner is characterized in that the control unit is designed and configured to detect an inadmissibly high load on the first electric motor and / or the second electric motor and, in response thereto, to change the operation of the second electric motor from a first direction of rotation to a second direction of rotation.

[0019] In other words, if an overload is detected or imminent overload of at least one of the two electric motors is detected, the vacuum cleaner's control unit is capable of reversing the rotation direction of the second electric motor, and thus of the floor brush, to the opposite direction of rotation in order to reduce the torque and thus the load. This prevents an overload-related or preventive overload-preventing shutdown of at least one of the two electric motors, which could be perceived by the user as a fault or defect in the vacuum cleaner.

[0020] According to one aspect of the invention, the control unit is designed and configured to detect an impermissibly high load on the first electric motor and / or the second electric motor based on the motor current, preferably by exceeding a motor current limit. This can enable a particularly simple implementation for detecting such a load without additional sensors. Preferably, depending on the selection of the limit, an impending overload can already be detected in order to prevent it.

[0021] The control unit is designed and configured to detect an impermissibly high load on the first electric motor and / or the second electric motor based on its heating, preferably by exceeding a limit value of a sensor-detected or modeled temperature. This can represent an alternative possibility, which may require sensor-detected temperature detection, whereby a temperature can alternatively be determined by suitable modeling of the respective electric motor. This can increase the effort on the part of the control unit due to the continuous modeling calculation, but in return avoids the costs, installation space, and the like of a temperature sensor.

[0022] According to a further aspect of the invention, the control unit is designed and configured to operate the second electric motor in the second direction of rotation at a lower speed than in the first direction of rotation. This can protect the surface and reduce the torque of the floor brush against the surface in order to reduce the load on the electric motors and thus avoid overloading them.

[0023] According to a further aspect of the invention, the rotating brush is designed to generate a higher torque in the first direction of rotation of the second electric motor by engaging a carpet as the underlying surface than in the second direction of rotation. This can be achieved by appropriately shaping the rotating brush or its bristles or combs. This can also contribute to protecting the underlying surface and / or minimize the strain or load on the electric motors.

[0024] According to a further aspect of the invention, the rotatable brush has a plurality of bristles or combs, which are formed and arranged on a roller of the rotatable brush such that the bristles or combs are oriented more radially in the first direction of rotation and more tangentially in the second direction of rotation. In other words, the bristles or combs of the rotatable brush are more in contact with the roller in the first direction of rotation and point more radially away from the roller in the second direction of rotation, whereby the torque of the floor brush relative to the surface can be influenced, i.e., can be kept lower in the first direction of rotation than in the second direction of rotation.

[0025] According to a further aspect of the invention, the vacuum cleaner is designed and configured so that the direction of rotation of the second electric motor can be adjusted by the user. This can allow the user to select the gentle cleaning method themselves, if necessary.

[0026] According to a further aspect of the invention, the second electric motor is designed to be brushless. This can increase the performance and / or longevity of the second electric motor of the rotating floor brush.

[0027] According to a further aspect of the invention, the first electric motor is designed to be brushless. This can increase the performance and / or longevity of the first electric motor of the fan.

[0028] According to a further aspect of the invention, the vacuum cleaner has a rechargeable electrical energy storage device, which is designed and configured to supply electrical power to at least the first electric motor, the second electric motor, and the control unit. The rechargeable electrical energy storage device can, in particular, be an accumulator or battery. This can allow the user to use the vacuum cleaner without the inconvenience of a cable for the electrical power supply.

[0029] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. It shows Figure 1 shows a schematic side view of a vacuum cleaner according to the invention in the form of a handheld vacuum cleaner according to the invention; and Figure 2 shows a perspective view of a floor brush of the vacuum cleaner according to the invention.

[0030] The above figure is viewed in Cartesian coordinates. There is a longitudinal direction X, which can also be referred to as depth X or length X. Perpendicular to the longitudinal direction X extends a transverse direction Y, which can also be referred to as width Y. Perpendicular to both the longitudinal direction X and the transverse direction Y extends a vertical direction Z, which can also be referred to as height Z.

[0031] The Figure 1 shows a schematic side view of a vacuum cleaner 1 according to the invention in the form of a handheld vacuum cleaner 1. The handheld vacuum cleaner 1 has a housing 10, which can be held and guided by a user by means of a handle 11. A fan 12 including a first electric motor 12a for driving the fan 12 is arranged in the housing 10. The first electric motor 12a is brushless. Furthermore, at least one filter and one exhaust opening are provided (not shown).

[0032] Opposite the handle 11, a suction tube 13 is arranged on the housing 10. At the end of the suction tube 13 applied to the housing 10, a suction nozzle 14 is provided, which can also be referred to as a floor nozzle 14 or a brush head 14. The suction nozzle 14 has an interior which is open downwards in the vertical direction Z by means of an opening 16, which can also be referred to as a suction opening 16. Arranged within the interior of the suction nozzle 14 is a rotatable brush 15 which can be driven in rotation by a second electric motor 15a. The second electric motor 15a is designed as a brushless, permanently excited DC motor.

[0033] The handheld vacuum cleaner 1 further comprises a control unit 17, which can operate both the first electric motor 12a and the second electric motor 15a. This can be done, in particular, via pulse-width-modeled signals. The first electric motor 12a, the second electric motor 15a, and the control unit 17 can be electrically supplied by a rechargeable electrical energy storage device 18.

[0034] The rotatable brush 15 has a roller 15b which can be rotated by the second electric motor 15a in a first direction of rotation and in an opposite second direction of rotation. The roller 15b has a plurality of rows of bristles 15c or combs 15c pointing radially outwards, which are arranged in an arcuate manner in the transverse direction Y of the rotatable brush 15. The rows of bristles 15c or combs 15c are also oriented more radially in the first direction of rotation and more tangentially in the second direction of rotation, i.e. they point away from the roller 15b in the first direction of rotation and lie more against the roller 15b in the second direction of rotation. This is pronounced to varying degrees across the width of the roller 15b in the transverse direction Y due to the arcuate shape.

[0035] If the handheld vacuum cleaner 1 according to the invention is now operated by the user by means of the two electric motors 12a, 15a, so that on the one hand an air flow is generated by the blower 12 by means of the first electric motor 12a and on the other hand the surface 2 is additionally cleaned by the rotating brush 15 by means of the second electric motor 15a, this can lead to the desired cleaning result on various surfaces 2 such as, for example, on tiles and short-haired carpets.

[0036] If the substrate 2 represents a comparatively normal-length or long-haired carpet, which opposes the rotational movement of the rotating floor brush 15 or its second electric motor 15a with a not inconsiderable mechanical resistance or generates a comparatively high torque, and / or if the comparatively long-haired carpet has a comparatively sealing effect on the intake opening 16 of the rotating floor brush 15 and thus significantly counteracts the air flow generated by the fan 12 or its first electric motor 12a, this can be detected by the control unit 17, for example by exceeding a respective limit value of the motor current.

[0037] According to the invention, this can be responded to in that the control unit 17 now reverses the direction of rotation of the second electric motor 15a, i.e. changes from the first direction of rotation to the opposite second direction of rotation. The second electric motor 15a is operated by the control unit 17 in the second direction of rotation at a lower speed than in the first direction of rotation, so that the surface 2 is brushed more gently and the torque with which the rotating brush 15a of the handheld vacuum cleaner 1 acts on the surface 2 is reduced. This allows the cleaning of the surface 2 to continue and, at the same time, the second electric motor 15a can be protected from overloading or overheating. This also leads to a reduced seal around the suction opening 16 of the rotating floor brush 15, so that the air flow can be maintained without overloading or overheating the first electric motor 12a.

[0038] The more thorough or gentler cleaning of the surface 2 can be supported by the design of the rotating brush 15, in which the bristles 15c or combs 15c are designed and arranged as described above. Thus, depending on the direction of rotation of the rotating brush 15 or its second electric motor 15a, they have a stronger or weaker effect on the surface 2 or penetrate a carpet, particularly a standard or long-pile carpet. Thus, the weaker effect on the surface 2 can be considered "stroking" and the stronger effect on the surface 2 can be considered "tapping."

[0039] Using the example of Fig. 2The weaker effect corresponds to a clockwise movement when viewed from the left side of the brush 15 (in the y-direction). As the brush 15 rotates, the bristles or combs 15c then strike the floor to a greater extent with their flat side, hence the term "stroking." The stronger effect, or "tapping," on the other hand, corresponds to a counterclockwise movement when viewed from the left side of the brush 15 (in the y-direction). As the brush 15 rotates clockwise, the bristles or combs 15c then strike the floor to a greater extent with their outer edge, hence the term "tapping." If the flat sides of the combs 15c hit the floor, they have a "softer" effect because, on the one hand, the impact area is larger and thus the force per area is lower, and, on the other hand, the combs 15c can attach relatively easily to the brush 15 and thus can "avoid" the floor covering more easily.If the outer edges of the combs 15c hit the floor during counterclockwise rotation, they have a "harder" effect because, on the one hand, the impact area is smaller and thus the force per area is greater, and, on the other hand, the combs 15c do not adhere as well to the brush 15, may even stand up more quickly and thus offer greater resistance to the floor covering.

[0040] In this case, the lower speed of the second direction of rotation of the second electric motor 15a of the rotating brush 15 can preferably be designed for the load point of a normal carpet as the substrate 2 in order to clean such a substrate 2 as energy-efficiently as possible. List of reference symbols (part of the description)

[0041] XLongitudinal direction; depth; length Zvertical direction; height 1 Vacuum cleaner; handheld vacuum cleaner 10 Housing 11 Housing handle 10 12 Blower 12a First (brushless) electric motor of the blower 12 13 Suction tube 14 Suction nozzle; floor nozzle; brush head 15 Rotatable (floor) brush; rotatable bristle roller 15a Second (brushless) electric motor of the rotatable (floor) brush 15 15b Roller of the rotatable (floor) brush 15 15c Bristles or combs of the rotatable (floor) brush 15 16 (Suction) opening 17 Control unit 18 Rechargeable electrical energy storage device; accumulator; battery 2Subsurface; floor; floor covering; area to be cleaned

Claims

1. Vacuum cleaner (1), preferably a handheld vacuum cleaner (1), comprising a fan (12) having an impeller for generating an air flow, a first electric motor (12a) for driving the impeller of the fan (12), a suction nozzle (14) having a rotatable brush (15), a second electric motor (15a) for driving the rotatable brush (15), and a control unit (17) which is designed and configured to operate at least the first electric motor (12a) and / or the second electric motor (15a), the control unit (17) being designed and configured to detect an inadmissibly high load on the first electric motor (12a) and / or the second electric motor (15a), and to change the operation of the second electric motor (15a) from a first rotation direction to a second rotation direction in response thereto, characterised in that the control unit (17) is designed and configured to detect an inadmissibly high load on the first electric motor (12a) and / or the second electric motor (15a) based on a temperature increase thereof, preferably by a limit value of a sensor-captured or modelled temperature being exceeded.

2. Vacuum cleaner (1) according to claim 1, wherein the control unit (17) is designed and configured to detect an inadmissibly high load on the first electric motor (12a) and / or the second electric motor (15a) based on the motor current, preferably by a limit value of the motor current being exceeded.

3. Vacuum cleaner (1) according to either of the preceding claims, wherein the control unit (17) is designed and configured to operate the second electric motor (15a) at a lower rotational speed in the second rotation direction than in the first rotation direction.

4. Vacuum cleaner (1) according to any of the preceding claims, wherein the rotatable brush (15) is designed to generate a higher torque in the first rotation direction of the second electric motor (15a) than in the second rotation direction, by engaging in a carpet as a substrate.

5. Vacuum cleaner (1) according to claim 4, wherein the rotatable brush (15) has a plurality of bristles or combs (15c) which are designed and arranged on a roller (15b) of the rotatable brush (15) such that the bristles or combs (15c) are aligned more radially in the first rotation direction and more tangentially in the second rotation direction.

6. Vacuum cleaner (1) according to any of the preceding claims, wherein the vacuum cleaner (1) is designed and configured such that the rotation direction of the second electric motor (15a) can be set by the user.

7. Vacuum cleaner (1) according to any of the preceding claims, wherein the second electric motor (15a) is brushless.

8. Vacuum cleaner (1) according to any of the preceding claims, wherein the first electric motor (12a) is brushless.

9. Vacuum cleaner (1) according to any of the preceding claims, further comprising a rechargeable electrical energy store (18) which is designed and configured to electrically supply at least the first electric motor (12a), the second electric motor (15a) and the control unit (17).

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