Cleaning devices, especially cleaning devices for robot vacuum cleaners

Abstract

The subject of the cleaning device according to the present invention is that a convex transfer surface (13) is positioned between a flat nozzle and a rotating brush (1). The flat nozzle is designed as a multi-channel nozzle (12) between the convex transfer surface (13) and an apron (26), and a bevel is provided at the entrance of the multi-channel nozzle (12) in a range of 20 to 60 degrees from the horizontal plane, and the gap height between the convex transfer surface (13) and the bottom (14) is in the range of 1 to 8 mm.

Description

Technology Field

[0001] The present invention relates to a cleaning device that ensures the supply of air flowing rapidly directly from the spiral housing of a centrifugal fan of a robot vacuum cleaner to the bottom surface, in particular to a cleaning device for a robot vacuum cleaner. Background Technology

[0002] In the field of robotic vacuum cleaners, developments are currently underway that follow trends in other categories of home appliances, focusing primarily on data sharing and the use of so-called artificial intelligence elements.

[0003] Above all, these are capital and energy-intensive navigation systems and applications for smartphones designed to remotely control and monitor the robot's operations. Some of these solutions, such as laser distance meters and computers that calculate the robot vacuum's current position based on changes in measured distance from objects within the cleaned space, consume nearly the same amount of energy as all other activities combined, particularly those involving drive wheels, fan drives, and all brushes.

[0004] The interior of a robotic vacuum cleaner is basically determined by its external dimensions, which must enable cleaning in limited conditions, such as between chair legs and under furniture.

[0005] The aforementioned limited internal space restricts the dimensions of components that must fit snugly into the robot vacuum cleaner, and most components must be located in designated positions for functional reasons; even the battery must be positioned to maintain the robot's balance. Additionally, the collection container for gathering cleaned dust must also have a specific minimum volume.

[0006] Therefore, the parameters of the elements participating in the cleaning activity itself are very limited and cannot be compared to the parameters and energy sources of a standard vacuum cleaner. For example, in the case of a standard mains-connected vacuum cleaner, the standard power input is 1,000W and the generated static sound pressure is about 20,000Pa. In the case of a robot vacuum cleaner, the fan's power consumption is about 6-20W and generates about 500-2,000Pa.

[0007] A critical requirement for optimal vacuuming is to induce a rapid airflow between the edge of the suction nozzle and the floor surface. It is desirable for the joint through which the air passes to be as narrow as possible and the flow rate to be as high as possible. In addition to the joint size, the key parameter is, precisely, the negative static pressure at a constant flow rate that allows the vacuum cleaner fan to operate; therefore, it is evident that a centrifugal fan equipped with a diffuser is used to achieve the cleaning effect with the smallest possible joint size. This is not only an obvious relationship between the joint cross-sectional area and the flow rate assuming the corresponding negative static pressure and flow, but an important assumption is that the thickness of the boundary layer on the floor surface needs to be reduced. However, it is difficult to achieve a sufficiently narrow joint with a robotic vacuum cleaner.

[0008] All related to this is that the range of impurity dimensions that must be removed from the surface and transferred to a collection container is very wide. These include not only dust, which typically has a size of about micrometers, but also organic and inorganic particles or objects with different densities and aspect ratios and sizes of about tens of millimeters. Leaves, debris, stones, hair, hair clumps, and so-called dust tufts are large, low-density formations that carry an electrostatic charge.

[0009] These basic requirements for robotic vacuum cleaners are currently being addressed through various technological approaches.

[0010] In the first of these technical approaches, the robotic vacuum cleaner uses a pair of counter-rotating rotary feed brushes with separate suction nozzles. The pair of counter-rotating brushes mechanically removes coarse dust from the floor surface and uses the kinetic energy mechanically imparted to the dust to transport it to a collection container.

[0011] Behind the aforementioned pair of brushes, a narrow suction nozzle formed by a pair of elastic elements is designed to reach directly above the cleaned surface, and the sucked-in fine dust is discharged pneumatically into a separate sealed collection container.

[0012] This design certainly addresses various types of impurities, but not entirely. It typically does not handle objects with large cross-sectional areas and low density, such as dust bundles. These accumulate in large quantities in room corners and under furniture and must be removed as they are clearly visible. However, a problem arises with the aforementioned configuration because the low specific gravity of the objects prevents the mechanical brush from providing sufficient kinetic energy, and the objects fail to reach the collection container due to their low specific gravity, large cross-sectional area, and significant aerodynamic drag. They usually fall back to the floor and, due to their size, cannot be sucked into the narrow suction nozzle. Consequently, they merely move along the floor in front of the nozzle and scatter as they move across the carpet.

[0013] Another disadvantage is the high space requirements for installing all elements and the need for two separate collection containers, which makes emptying the containers inconvenient and takes a long time to clean. Additionally, the system is complex, and the dust-free brush swirls, causing hair to get severely tangled in the brush and bearings, requiring removal from both.

[0014] Another technical solution uses a simple suction nozzle. The biggest problem with this design is related to the specifications of the robot vacuum cleaner. Unlike the suction nozzle of a vacuum cleaner operated by a normal human, a robot vacuum cleaner typically requires a constant overhead clearance of 8 mm to overcome vertical obstacles such as carpets, skirting boards, and door sills.

[0015] Dust particles can range in size up to the millimeter, and unlike conventional vacuum cleaners, the suction device of a robotic vacuum must take this fact into account. When a floor cleaner spots debris, they simply raise the nozzle and continue cleaning with the nozzle resting on the surface. A robotic vacuum, however, must clean everything passing beneath its frame—that is, all dust ranging from micron-sized particles to those in 8mm gaps. The structure of the suction nozzle and the dimensions of the air duct through which the dust passes to the collection container must correspond to this. In practice, this means the minimum size of the suction nozzle must be 8mm, and this applies to the air duct as well.

[0016] However, this means that high flow rates cannot be achieved on the floor surface due to the large cross-sectional area of ​​the suction nozzle required to maintain permeability to large impurities with this design, and the limited amount of airflow that the fan can supply due to low power input and dimensions. Additionally, the nozzle is compressed precisely at the inlet of the front part of the nozzle, at the bottom of the robot vacuum cleaner frame, on the opposite side from what is needed. On the floor surface, a flow rate of only 4-5 m / s is typically achieved.

[0017] The suction nozzle must be open at the front to allow large impurities to pass through, and paradoxically, although the volume of these large impurities accounts for only a percentage of the total volume of impurities, the need to clean them prevents the creation of a narrow joint, and thus makes it impossible to achieve the high flow rate required to remove fine dust particles. At the same time, these constitute the majority of the volume of impurities and are much more dangerous to health than large, visible debris.

[0018] The third design approach is based on a rotary brush located in the vacuum section of the air duct. The rotary brush, driven by an electric motor, is partially enclosed, and the air duct, where the air pressure is negative, opens into the housing. Behind the brush, a screen extending just above the bottom surface is located.

[0019] Particles of sufficient density and size are struck by the brush blade on the floor, transported to the brush shaft, and discharged into the air duct and collection container by centrifugal force. Particles of lower density and fine dust partially flow around the brush and are transported to the collection container by the flow of air sucked in from the floor.

[0020] This technical solution has several disadvantages. The airflow on the floor is determined by the circumferential speed of the brush, and it only slightly exceeds this speed due to residual flow between the brush blade and the brush housing. In robotic vacuum cleaners, the circumferential speed of the brush is typically 2 meters per second, with a diameter of 40 mm and 17 rotations per second. While this speed is sufficient for removing larger impurities in the case of mechanical tools, it is completely insufficient for separating impurities from the surface in the case of airflow. In this structure, the airflow does not serve as one of the primary tools for surface cleaning, but rather acts as an auxiliary means for removing fine dust blown by the brush and transporting it to a collection container. This design also has the problem of hair getting tangled around the brush because the peripheral flow is too slow.

[0021] The fourth possibility of the prior art is a solution based on a pair of profiled counter-rotating elastic cylinders positioned within a vacuum air duct that simultaneously forms a suction nozzle.

[0022] This solution has the following technical disadvantages. The air duct is characterized by abrupt changes in cross-sectional area, which induces turbulence around the profiled cylinder and causes sealing problems for the profiled rotating cylinder. When cleaning carpets, the gap height of the robot vacuum cleaner changes due to the high surface load of the drive wheel, and consequently, the geometry of the suction device relative to the floor changes. The roller profile sinks completely into the carpet surface, and turbulence increases further in the remaining holes between the roller and the floor. The flow velocity in the remaining holes on the floor was measured at 2 m / s.

[0023] Due to the design of the device having a small tolerance between the roller and the shaft, tangled hair is a major problem, which also blocks the channel between the roller and the floor and blocks the airflow. means of solving the problem

[0024] The present invention is based on a design aimed at supplying air flowing rapidly directly to the bottom surface from at least one side duct of a spiral housing or centrifugal fan, the essence of which is a fan having an inlet side and an outlet side; a rotating brush comprising a plurality of rotating blades—the rotating brush is located in a rotating brush chamber connected to the inlet side of the fan to form negative air pressure inside—; The device includes a positive-pressure subsystem configured to receive pressurized air from the outlet side of the fan and to deliver a high-speed pressurized airflow over a surface through a flat nozzle in a forward direction toward the rotating blade, and a convex transfer surface having a convex curvature is positioned behind the flat nozzle, and the convex transfer surface, when viewed from the flat nozzle, first bends downward to a transfer line which is the lowest point of the convex transfer surface, and then bends upward to a raised discharge edge adjacent to the rotating brush chamber, and the convex transfer surface is positioned and arranged within the device to move along the convex curvature between the convex transfer surface and the surface to be cleaned until the high-speed pressurized airflow exits the flat nozzle and reaches the transfer line of the convex transfer surface, at which point the airflow flows tangentially to the surface to be cleaned, and the change in static pressure acting on the high-speed pressurized airflow by the convex curvature of the convex transfer surface causes the airflow to flow along the surface to be cleaned in a forward direction toward the rotating blade.

[0025] The outlet of the flat nozzle further includes an apron positioned at the outlet facing the forward direction of the high-speed pressurized flow to restrict the penetration of ambient air into the convex transfer surface, and the flat nozzle is a multi-channel nozzle positioned between the convex transfer surface and the apron, and the multi-channel nozzle has an orifice inclined at 20 to 60 degrees from the surface to be cleaned, and the gap height between the transfer line of the convex transfer surface and the surface to be cleaned is in the range of 1 to 8 mm.

[0026] The fan is a centrifugal fan housed within a spiral housing, and a flat nozzle is continuously connected to the spiral housing or at least its side duct by a multi-channel airflow straightener, the multi-channel airflow straightener having multiple channels connected to a system of individual air ducts, and the individual air ducts terminate at the inlet of the multi-channel nozzle.

[0027] The multi-channel nozzle has a reduced cross-sectional area between the opening of the individual air duct and the opening of the multi-channel nozzle.

[0028] The rotary brush chamber is housed within the housing and connected to the collection container by an elastic coupling.

[0029] The apron is rounded toward the surface to be cleaned as it moves away from the opening of the multi-channel nozzle, and the apron has a maximum gap height in the range of 0.5 to 2 mm from the surface to be cleaned, and the gap height of the apron is smaller than the gap height of the convex transfer surface.

[0030] The raised discharge edge of the convex transfer surface forms the lowest edge of the rotary brush chamber.

[0031] The rotary brush chamber is positioned between a first air duct connected to a collection chamber and a second air duct containing a high-speed pressurized airflow passing through a flat nozzle.

[0032] The second air duct has one or more outlets, and the sum of the cross-sectional areas of these one or more outlets is 3 to 40% of the cross-sectional area of ​​the first air duct.

[0033] The high-speed pressurized airflow flowing toward the rotating brush through the flat nozzle includes a laminar flow of overpressure air, and the laminar flow of overpressure air enters the rotating brush chamber and collides with a plurality of rotating blades of the rotating brush, thereby causing turbulence and deceleration of the overpressure air. The device includes a robotic vacuum cleaner structure, and the rotating brush chamber and the flat nozzle are suspended from a plurality of parallel pivot arms mounted on pins rotatably mounted on lugs fixed to the robotic vacuum cleaner structure. The fan is a centrifugal fan, and the device includes a flat supply channel or at least one side supply channel disposed between the flat nozzle and the centrifugal fan.

[0034] The device includes a collection container fluidly connected between a rotating brush chamber and a fan.

[0035] By means of a set of air ducts having a small cross-sectional area, the present invention provides sufficient flow at a given flow rate, while the sufficiently low hydraulic dimension of the individual air ducts creates a condition for laminar flow. This minimizes energy loss and flow velocity due to turbulence, and the flow is uniformly distributed along the entire convex transfer surface, thus eliminating abrupt bends in the duct and abrupt changes in cross-sectional area.

[0036] The air duct assembly connects the spiral housing outlet of the centrifugal fan in series to a corresponding small-diameter air duct assembly to calm the turbulence from the spiral housing outlet of the centrifugal fan. This ensures a smooth physical transition between the spiral housing outlet and the small-diameter air ducts with various cross-sectional areas and shapes, and also ensures a smooth transition between the turbulent airflow from the spiral housing outlet of the centrifugal fan and the laminar flow within the small-diameter ducts.

[0037] A centrifugal fan with a spiral housing can be replaced by a centrifugal fan having at least one side channel or side duct, which is the optimal method for converting the kinetic energy of air obtained from the blades of a rotating impeller into static energy. The efficiency of the side channel design is much higher in converting kinetic energy into static energy than in the use of a spiral housing, while minimizing the external dimensions of the centrifugal fan.

[0038] The convex transfer surface supplies a high-speed fluid bed from a flat multi-channel outlet nozzle to the bottom surface. At the lowest ground clearance, the flowing high-speed fluid bed changes the flowing convex transfer surface to the bottom surface because the direction of the static pressure differential compressing the high-speed fluid bed against these surfaces changes. By making the high-speed air bed parallel to the bottom surface, unlike sloping direct air flow, contaminated air is prevented from escaping because the kinetic pressure of the air bed flowing parallel to the bottom implies a static pressure lower than the surrounding atmosphere. Therefore, dust-contaminated air cannot escape to the surroundings.

[0039] Conventional technology is also improved by using a much simpler nozzle and air duct design that can be a simple slit, and by using a simpler and cheaper centrifugal fan designed for low speeds, which reduces the need to mount a centrifugal fan impeller and the requirements for its cooling and balancing.

[0040] Air flowing rapidly over a surface creates a region of lower static pressure above the surface than below, such as between the fibers of a carpet. This generates the desired upward suction, which releases dust particles from the spaces between the carpet fibers into a high-speed flow and further transports them to a collection container.

[0041] Therefore, for example, when traversing between different types of floor covers, if part or all of the convex conveying surface moves further away from the floor than the thickness of the high-speed airflow fluid bed, unwanted dust scattering from the floor surface is prevented. At the mentioned location on the surface, the flow around the surface is completed up to the rear edge of the convex conveying surface, the airflow is discharged into the space of the rotating brush, decelerated, and discharged into the collection container.

[0042] The convex shape of the transfer surface ensures smooth overcoming of protruding surfaces such as carpet edges or door thresholds, and thus the convex transfer surface can be placed directly above the floor and allows high-speed flow to be placed in a thin layer directly above the surface, making it energy efficient.

[0043] The working distance between the lowest point of the convex transfer surface and the bottom surface is directly proportional to the vertical dimension of the flat multi-channel nozzle—from which a high-speed air jet layer is discharged to the convex transfer surface—and the trajectory that changes the area where the current flows. When the robotic vacuum cleaner moves on the floor in a standard horizontal position, the joint between the convex transfer surface and the bottom surface maintains its fixed size to ensure the desired surface flow change.

[0044] When the convex transfer surface moves further from the bottom surface than the thickness of the fluid bed of the high-speed airflow, the flow of the convex transfer surface is completed only at the rear edge of the convex transfer surface, which is determined by the intersection point between the convex transfer surface and the inner surface of the rotating brush case, and the airflow is discharged into the space of the rotating brush, decelerated, and collected in the collection container.

[0045] This redirects airflow from the floor surface and prevents dust from being blown away and contaminated air from leaking into the atmosphere without control.

[0046] An important aspect is the relationship between the circumferential speed of the rotating brush and the flow rate around the convex transfer surface, which is provided by the control unit. The goal is to maintain a dynamic balance in terms of the mechanical effect of the rotating brush on dust particles and the aerodynamic effect opposite to the high-speed flow, and to maintain a dynamic balance between the volume and velocity of the air escaping from beneath the rotating brush and the velocity of the particles accelerated toward the joint by the rotating brush. More precisely, the velocity of the air escaping from beneath the brush must be reduced to zero even under the robot vacuum cleaner body, and no particles must penetrate under the convex transfer surface against the airflow.

[0047] The rotary brush acts as a flow equalizer in the overpressure and low-pressure branches of the air duct. The high-speed flow from the convex conveying surface moves particles from the bottom surface, and subsequently, this air saturated with dust particles is forced to decelerate to the speed of the suction low-pressure branch in a chamber temporarily formed between the rotary blades, thereby avoiding problems caused by the difference in air flow speed between the two branches of the air duct.

[0048] An apron with side plates surrounding the rear space of a flat multi-channel nozzle having a convex transfer surface whose distance from the bottom surface is smaller than the distance from the bottom surface limits the amount of air that can be drawn from the surrounding atmosphere into the depressurization region because it bypasses the high-speed flow from the flat nozzle and the cylindrical convex transfer surface.

[0049] At the same time, reducing the intake volume alleviates the problem of maintaining a constant volume of air and decreases the deceleration and growth of the air layer flowing around the cylindrical convex conveying surface, which leads to an increase in floor cleaning efficiency.

[0050] At the same time, the apron is designed as an auxiliary device to ensure a minimum distance between the lower surface edge of the convex transport surface and the bottom surface, thereby ensuring proper functioning of airflow beneath the convex transport surface.

[0051] The entire cleaning unit, including a convex feed surface, a flat multi-channel nozzle, an apron with side plates to reduce air intake, a rotary brush with a motor and gearbox, and a rotary brush chamber with a vacuum air duct, is connected to the collection container housing by an elastic transition element and suspended from parallel pivot arms mounted on pins of the robot vacuum cleaner frame. This solution compensates for variations in the ground clearance of the robot vacuum cleaner caused by differences in the surface hardness of the surface on which the robot vacuum cleaner operates, namely wooden floors or soft carpets. With the typical weight of the robot vacuum cleaner, the typical difference in ground clearance is up to 3-4 mm.

[0052] Maintaining a preset constant height gap from the lowest edge of the convex transfer surface above the floor is crucial for ensuring proper airflow transfer from the convex transfer surface to the floor. This prevents excessive friction and unwanted bending of the rotating brush blades, thereby protecting the motor and saving energy; it also prevents excessive carpet wear caused by the rotating brush and supports the navigation system by avoiding the introduction of unnecessary acceleration that must be evaluated by the robot vacuum cleaner navigation system.

[0053] A centrifugal high-speed fan with backward-curved blades, a semi-closed impeller, and a spiral housing generates high static-pressure airflow at the expense of lower flow rates. One of the fundamental ideas of the present invention is a differentiated approach for removing various categories of surface impurities. The primary role of the airflow is to remove fine dust particles for which high-speed flow is most suitable. Given the typical size of these particles measured in micrometers, the decisive factor is not the force of the airflow over the surface to be cleaned or the thickness of the layer of air. Therefore, a thin layer in the range of 1–2 mm is entirely sufficient to remove the particles from the surface and from the spaces between the carpet fibers. Brief explanation of the drawing

[0054] Exemplary embodiments of the present invention are illustrated in the accompanying drawings. FIG. 1 illustrates a partial cross-sectional view of a robot vacuum cleaner in an axonometric view illustrating the location of the main features of the present invention. FIG. 2 illustrates a partial cross-sectional view of a robot vacuum cleaner illustrating the location of the cleaning device. FIG. 3 illustrates a partial cross-sectional view of a robot vacuum cleaner illustrating the location of the cleaning device when the robot vacuum cleaner is traveling on a soft surface. FIG. 4 illustrates a detailed cross-sectional view of a robot vacuum cleaner equipped with a rotary brush, a rotary brush housing, a flat multi-channel nozzle, an apron with side plates, and a vertically movable hinge. FIG. 5 illustrates a detailed cross-sectional view of the cleaning device showing the airflow under the rotary brush blade. FIG. 6 schematically illustrates the dependence of the change in flow velocity on the slit size and time under the rotary brush blade. FIG. 7 illustrates a bottom view of the robot vacuum cleaner body showing the process of the flow velocity under the blade of the rotary brush. FIG. 8 illustrates a front view of the robot vacuum cleaner in a horizontal working position. FIG. 9 illustrates a side view of the robot vacuum cleaner in a horizontal working position. FIG. Figure 10 illustrates a detailed cross-sectional view of a cleaning device showing airflow in a horizontal working position. Figure 11 illustrates a front view of a robot vacuum cleaner in an inclined cross position. Figure 12 illustrates a side view of a robot vacuum cleaner in an inclined cross position. Figure 13 illustrates a detailed cross-sectional view of a cleaning device showing airflow in the inclined cross position of the vacuum cleaner. Figure 14 illustrates a detailed embodiment of a robot vacuum cleaner cleaning device during operation on a carpet at the stage where dust comes into contact with the rotating brush. Figure 15 illustrates a detailed embodiment of a robot vacuum cleaner cleaning device during operation on a carpet at the stage where dust is transported in the space between the rotating brush blade and the rotating brush housing.FIG. 16 illustrates a detailed embodiment of a robotic vacuum cleaner cleaning device during operation on a carpet, in the step where dust is discharged from the space between the blades into the vacuum section by the rotating brush blades. FIG. 17 schematically illustrates an exploded view of the robotic vacuum cleaner cleaning device between the air duct and the rotating brush. FIG. 18 illustrates a partial cross-sectional view of a multi-channel nozzle. FIG. 19 illustrates an exploded view of a centrifugal regulator having a side duct. Specific details for implementing the invention

[0055] The present invention relates particularly to a robot vacuum cleaner comprising a rotating brush (1) driven by a driving motor (23) controlled by a control unit in relation to the power input of an electric motor (8) driving a centrifugal fan (7) and partially encapsulated by a housing (3), and a vacuum section (2) of an air duct, wherein one end of the vacuum section (2) of the air duct is connected to the housing (3) of the rotating brush (1) and the other end is connected to the housing of a dust collection container (4) through an elastic coupling (22), the dust collection container is connected to the inlet air duct (6) of the centrifugal fan (7) through an air filter (5), and the centrifugal fan is provided with an impeller (46) having a blade that is slightly bent backward and driven by an electric motor (8). A centrifugal fan (7) is enclosed in a spiral housing (24) having an inlet duct (49) and a side duct (47) with an air outlet (9), and is connected to a multi-channel air flow straightener (10) of air flow, the number of channels corresponding to the number of outlets, and at one end of the outlet, an equal number of small hydraulic air ducts (11) are connected to the side of the centrifugal fan (7) connected to the multi-channel straightener (10) by an adhesive joint, and at the other end, the ducts are mounted in equal numbers by conical shoulders into the recesses of the upper part (12a) and lower part (12b) of the circular portion of the air duct of a flat multi-channel nozzle (12). By molding the air ducts, connections to an equal number of flat openings forming the flat multi-channel nozzle (12) are created. A bar (40) with a hole that serves to pass through the air duct (11) acts as a cap connecting the upper part (12a) and the lower part (12b) of the flat multi-channel nozzle (12).

[0056] Alternatively, instead of a multi-channel straightener (10) having multiple air ducts (11), a spiral housing (24) and a flat nozzle can be connected using a single straight flat supply duct or at least one side supply duct with a larger cross-sectional area, and this technical solution also provides an outlet air velocity much higher than the velocity of the suction vacuum air.

[0057] The spiral housing (24) of the centrifugal fan (7) can generally be replaced with a side channel or side duct (47) or a pair of side channels placed below the impeller blade of the centrifugal fan (7). This saves space for the entire device, and given the dimensions of the centrifugal fan (7), a higher static outlet air pressure is achieved.

[0058] The flat multi-channel nozzle (12) illustrated in FIGS. 17 and 18 is formed by an upper portion (12a) that is detachably connected to the housing (3) of the rotating brush (1) by a rod (45) and a lower portion (12b) that are closed at the side by a side plate (41) and connected by a connecting element (42), and is connected to one side of the convex transfer surface (13), the convex transfer surface intersects the inner surface of the housing (3) of the rotating brush (1), which is driven by a driving motor (23) at the other end, to form the raised rear edge (25) of the convex transfer surface (13).

[0059] The apron (26) with the side plate (41) is positioned below the flat multi-channel nozzle (12). The entire assembly is suspended from a pivot arm (27) hinged by a pin (28) to a hole in the lug (29) on the robot vacuum cleaner body.

[0060] The principle of air recirculation in a robotic vacuum cleaner is to maintain a constant flow and total pressure throughout the entire system, but the flow velocity changes and the static pressure and dynamic pressure within the flow change similarly. The air duct is divided into a vacuum low-speed subsystem including a housing (3) of a rotating brush (1)—the rotating brush (1) itself is driven by an electric drive motor (23)—and a high-pressure overpressure subsystem including a system of air ducts (11) having a small hydraulic size.

[0061] The high-pressure high-speed subsystem supplies a high-speed flow into a flat multi-channel nozzle (12) formed by a series of flat outlets, at which the flow is further accelerated by reducing the outlet cross-sectional area. Additionally, the flow is supplied along the surface of a convex transfer surface (13) near a cleaned floor surface (14). After the high-speed pressurized air flow (17) reaches the transfer line (15) closest to the surface of the floor (14), the layer of the high-speed pressurized air flow (17) has a thicker thickness than at the inlet of the outlet opening of the flat multi-channel nozzle (12). As it flows around the convex surface (36) of the convex transfer surface (13), the increase in the thickness of the air layer is caused in an undesirable way by suction (18) into a lower static pressure area accompanied by the high-speed pressurized air flow (17). The rate of increase in the thickness of the air layer is directly proportional to the length of the trajectory along the surface of the convex transfer surface (13) from the flat multi-channel nozzle orifice to the transfer line (15), because the fluid layer is exposed to ambient air along the entire length of the trajectory. To limit this growth, an apron (26) with a side plate (41) is designed, wherein the side plate (41) limits the penetration of ambient air into the surface of the convex transfer surface (13), thereby limiting the degree of undesirable suction (18) and thus also limiting the increase in the thickness of the air layer.

[0062] When reaching the transfer line (15), the high-speed pressurized air flow (17) changes the flowed-around surface from the convex transfer surface (13) to the bottom surface (14), because the bottom surface (14) forms a tangential surface of the convex transfer surface (13) in the transfer line (15). At the same time, the sign of the difference in static pressure acting on the high-speed fluid bed changes in the transfer line (15).

[0063] The above static pressure difference arises from the fact that, on the solid surface side, the overpressure from the free atmosphere side acts on the flow air layer, which is characterized by a higher dynamic pressure and a lower static pressure that pressurizes the flow layer against the solid surface.

[0064] A high-speed pressurized air flow (17) accompanied by dust particles flows around a cleaned floor surface (14) against a blade (16) of a rotating brush (1) rotating with a circumferential velocity vector in the opposite direction at a dead center lower than the vector of the high-speed pressurized air flow (17), and the velocity in a given cross-sectional area corresponds to a circumferential velocity of 5-10% of the velocity of the high-speed pressurized air flow (17). Dust particles, along with any large object (21) picked up by the blade (16) of the rotating brush (1), are found together with reverse-moving particles accompanied by the high-speed pressurized air flow (17) in strong turbulence upon contact between the blade (16) of the rotating brush (1) and the high-speed pressurized air flow (17), are transported by the rotating brush (1) into a vacuum section (2) of an air duct between adjacent pairs of blades (16) of the rotating brush (1), and are transported to a dust collection container (4) by slow-flowing air, where they are stopped by an air filter (5).

[0065] During rotation, the adjacent pair of blades (16) of the rotating brush (1) and the inner wall of the housing (3) of the rotating brush (1) form a temporary closure of the chamber (31) at the moment of passing through the housing (3), and due to the formation of strong turbulence and vortices, the dissipation of kinetic energy and increase in static pressure occur, so that when the decelerated turbulence (39) enters the space of the vacuum section (2) of the air duct, the flow has speed and pressure parameters comparable to those that have been naturally developed in the vacuum section (2) of the air duct by the centrifugal fan (7).

[0066] The connection between the operation of the overpressure and low-pressure air subsystems means that the two air subsystems are connected not only structurally but also functionally by a partially enclosed rotating brush (1), representing a first mode of synergistic interaction between the high-speed pressurized air flow (17) and the rotating brush (1) itself.

[0067] Specifically, the position of the rotating brush (1) equipped with a blade (16) between the vacuum section (2) of the air duct and the high-speed pressurized air flow (17) flowing around the bottom surface (14) allows the desired high-speed difference between the low-pressure flow and the high-pressure flow to be utilized.

[0068] In a preferred embodiment, the ratio between the flow velocity at the inlet of the flat multi-channel nozzle (12) and the velocity in the vacuum section (2) of the air duct is 16:1, and more precisely, the flow velocity in the vacuum section (2) of the air duct is 5 m / s and the flow velocity at the inlet of the flat multi-channel nozzle (12) is 80 m / s.

[0069] It is clear that without forced deceleration occurring inside the housing (3) of the rotating brush (1), the speed cannot be reduced over the short distance between the transfer line (15) and the vacuum section (2) of the air duct, because speed compensation in a natural way, that is, by friction between the high-speed flow and the surrounding atmosphere, requires a distance of about 500 mm.

[0070] The low flow rate in the vacuum section (2) of the air duct is determined by the need for sufficient permeability of the vacuum section (2) of the air duct, because all dust particles, including large objects (21) passing under the robot body, must have enough space to safely pass through the vacuum section (2) of the air duct and be delivered to a collection container (4) housed in a shaft with walls (32). In contrast, for the overpressure air duct (11), such limitations do not exist. For this reason, the cross-sectional area of ​​the overpressure air duct (11) or the sum of the cross-sectional areas of the individual overpressure air ducts and their outlets in the flat multi-channel nozzle (12) can be reduced compared to the cross-sectional area of ​​the vacuum section (2) of the air duct. In a preferred embodiment, the sum of the cross-sectional areas of the outlets of the overpressure air duct (11) is about 5% of the cross-sectional area of ​​the vacuum section (2) of the air duct. The result is a desirable increase in flow rate, which has a positive effect on the cleaning effect on the floor surface (14) despite the slight deceleration during the flow around the convex conveying surface (13) due to friction with the surrounding air accompanied by turbulence (35), because the high-speed flow creates an area of ​​reduced static pressure over the floor surface (14) and thus induces the desired upward suction (19), which also releases dust that would otherwise be inaccessible from the spaces between the carpet fibers.

[0071] For the efficiency of the cleaning effect, the inlet angle of the flat nozzle or multi-channel nozzle (12) covering the floor surface (14) is also important. An increase in this angle is related to the extension of the trajectory that air must travel between the inlet of the multi-channel nozzle (12) and the transfer line (15). Due to turbulence (35), the air velocity decreases, and the volume of air sucked into the transfer line (15) and the thickness of the air layer in the transfer line (15) increase due to unwanted suction (18).

[0072] The upper limit of the angle is limited by the condition that no separation occurs, indicated by the separation line (27), before the air reaches the raised rear edge (25). This is related to the ratio of the thickness of the flow air layer to the radius of the convex transfer surface (13). The lower this ratio, the faster the air separates from the convex transfer surface (13), and the lower the upper limit of the inlet angle of the flat nozzle or multi-channel nozzle formed with the bottom surface (14).

[0073] The lower limit of this angle is limited by two factors. In the case of a multi-channel nozzle (12), individual airflows need to be combined into a single flow at the level of the transfer line (15). This depends on the length of the trajectory, the size of the gap between the outlets of the individual channels, and the shaping of the ends of the individual channels, which can be designed to be tapered or expanded. For all flat nozzles, the smallest angle is given by the fact that the nozzle body and the adjacent apron (26) do not present an obstacle to the robot vacuum cleaner when crossing, for example, uneven surfaces or thresholds.

[0074] Beyond the traditional technical task of a rotary brush (1) in collecting coarse dust from a floor surface (14), beating a cleaned floor, particularly a carpet, and transporting loose dirt to a vacuum section (2) of an air duct, in a preferred embodiment of the present invention, a rotary brush (1) equipped with a blade (16) acts as a flow rate moderator between a high-speed flow from an overpressure subsystem that provides sufficient cleaning effect and a low-speed vacuum subsystem with a large cross-sectional area, thereby making it possible to transport even large dust particles to a collection container (4).

[0075] The high-speed pressurized air flow around the convex transfer surface (13) is closest to the bottom surface (14), and the transfer line (15) that changes the surrounding flow surface from the convex transfer surface (13) to the bottom surface (14) must be as close as possible to the rotating brush (1) equipped with blades (16), so that the maximum possible number of dust particles emitted from the bottom surface (14) by the high-speed pressurized air flow are transferred to the blades (16) of the rotating brush (1) due to inertial force. In particular, high-density particles travel along a trajectory similar to a ballistic curve when emitted from the surface, because the flow velocity that moves the particles still far exceeds the velocity of the particles but decreases rapidly. The gap height of the convex transfer surface (13) is most often in the range of 1 to 8 mm and also depends on the vertical dimension of the flat nozzle, because in the case of a thin layer of air cleaning the convex transfer surface (13) that is too far from the bottom (14), the air flow will not be transferred from the convex transfer surface (13) to the bottom (14), and the air will flow to the raised rear edge (25) and the system will not work.

[0076] At the same time, in the space between the blade (16) and the transfer line (15), it is desirable that the flow rate be as high as possible so that particles mechanically ejected by the blade (16) of the rotating brush (1) are deflected upward into the space of the housing (3) of the rotating brush (1) by a flow-induced aerodynamic force. In this way, penetration of particles through the slit (20) below the transfer line (15) is prevented.

[0077] Since the distance (43) between the lowest level of the convex transfer surface (13) and the lowest level of the rotating brush (1) must be short, the speed of the high-speed pressurized air flow (17) is much higher than the speed of most particles emitted and stirred by this flow at the point of reaching the blade (16), and at the same time exceeds the flow rate of the vacuum section (2) of the air duct many times. To prevent backflow from the vacuum section (2) of the air duct, which may occur due to the large difference in flow rates, the high-speed pressurized air flow (17) must be decelerated in a controlled manner, and as a result, a decelerated turbulent airflow (39) having a speed equal to or close to the flow rate in the vacuum section (2) of the air duct is generated. In the presented preferred embodiment of the invention, this objective is achieved by using the blade (16) of the rotating brush (1) as described above.

[0078] An important feature of the function of the robot vacuum cleaner according to the present invention is the ratio of the sum of the outlet cross-sectional areas of the high-pressure air duct (11) of the high-speed part of the air duct, which is 3-40% of the cross-sectional area of ​​the vacuum section (2) of the air duct. An upper limit of this range is possible when using a low-pressure centrifugal fan.

[0079] Since the robot vacuum cleaner operates autonomously on the floor, it must be able to overcome vertical obstacles such as carpets, floorboards, and door sills. When the robot vacuum cleaner overcomes an obstacle, the cleaning element, which is mainly a flat multi-channel nozzle assembly (12) with a rotating brush (1) and a convex transfer surface (13), changes its position relative to the floor surface (14).

[0080] As illustrated in FIGS. 11 and 12, at the moment when the flat multi-channel nozzle assembly (12) having a rotating brush (1) and a convex transfer surface (13) rises wholly or partially over the bottom surface (14) such that the distance between the transfer line (15) and the bottom (14) exceeds the thickness of the flow air layer, the high-speed pressurized air flow (17) from the multi-channel nozzle (12) flowing around the convex transfer surface (13) does not change the flow surface to the bottom surface (14), but flows around the convex transfer surface (13) to the raised rear edge (25) which guides the flow directly into the housing (3) of the rotating brush (1). This prevents the air from escaping into the atmosphere and swirling dust on the bottom surface (14).

[0081] The apron (26) with side plates limits the unwanted intake (18) of air from the surrounding atmosphere into the depressurization zone caused by the high-speed flow from the flat multi-channel nozzle (12) and the flow around the convex transfer surface (13).

[0082] The apron (26) with the side plate (41) surrounds the space behind the convex transfer surface (13) and features a gap height smaller than that corresponding to the distance of the transfer line (15) from the bottom surface (14).

[0083] Compensation for the increase in air volume due to desired suction (19) and unwanted suction (18) occurs in a controlled manner by allowing pulsating air (38) to escape through a periodically created pulsating gap (44) under the blade (16) of the rotating brush (1) so that the flow velocity under the rotating brush (1) is still reduced to 0 m / s under the robot vacuum cleaner body. Even within this flow, the static pressure is lower than the surrounding atmosphere, and because the flow stops under the robot vacuum cleaner, leakage of impurities into the surrounding atmosphere cannot occur.

[0084] There are two different aspects to the synergy between the rotating brush (1) and the high-speed pressurized air flow (17).

[0085] The first of these relates to the usability of the rotating brush (1), more precisely to its circumferential speed. The higher the circumferential speed of the rotating brush (l), the greater the effect of the blade (16) on dust and the cleaning effect. More specifically, the positive effect is that the number of interactions between the blade (16) and the floor surface (14) per unit time is greater, which increases the probability of dust intervention and the intensity of dust release from the carpet fibers.

[0086] In the prior art of a robot vacuum cleaner, the rotational speed of the rotating brush and its circumferential speed are limited, because for the reasons explained above, the speed of the vacuum flow along the brush is low and there is only a mechanical apron behind the brush that must maintain a constant ground clearance (30) above the floor surface so as not to hinder the robot from moving and overcoming vertical obstacles.

[0087] In the present preferred embodiment, the mechanical apron is replaced by the pneumatic effect of a reverse high-speed pressurized air flow (17) that completely seals the space between the transfer line (15) and the bottom surface (14). Thanks to the described sealing means, the rotational speed of the rotating brush (1) can thus be significantly increased compared to the prior art. The higher the speed of the high-speed pressurized air flow (17), the faster the rotational speed of the rotating brush (1) can be. That is, there is a multiplier effect whenever the speed of the high-speed pressurized air flow (17) increases, because the circumferential speed of the rotating brush (1) and the resulting increase in cleaning effect also increase.

[0088] The second synergistic effect relates to the effect of the blade (16) on particles trapped between the carpet fibers. The blade (16) strikes dust particles on the surface, particularly on the carpet surface, at a normal speed of 1000 rpm and about 17 rotations per second, corresponding to a frequency of about 100 strokes per second in a conventional paddle brush. At this frequency, the carpet fibers where the dust particles are trapped are struck and bent, causing the particles to be mechanically released, and a significant portion of them move closer to the surface or jump onto the surface. Then, these particles are cleaned directly or secondarily by a high-speed pressurized airflow (17) based on the mechanism previously described.

[0089] The housing (3) of the rotating brush (1), which is equipped with a flat multi-channel nozzle (12), an apron (26) having a side plate (41) for reducing air intake, a convex transfer surface (13), an electric motor (8), and a gearbox, and a vacuum section (2) of an air duct connected to the wall (32) of the housing of the collection container (4) by an elastic coupling (22), is entirely suspended from a parallel pivot arm (27) suspended from a pin (28) on a lug (29) of the robot vacuum cleaner structure.

[0090] This hanging compensates for changes in the robot vacuum's ground clearance caused by differences in the hardness of the surfaces on which the robot vacuum operates, such as wooden floors or soft carpets. At typical densities of the robot vacuum, the usual difference is 3-4 mm.

[0091] The position of the self-leveling structure on a hard surface is illustrated in FIG. 2. On a hard surface, the relative vertical positions of the driving wheel (33) and the auxiliary wheel (34) with respect to the self-leveling structure, particularly the vertical position of the blade (16), more precisely the vertical position of the axis of the rotating brush (1) where the blade (16) of the rotating brush (1) moves in close contact with the bottom surface (14) and the blade (16) of the rotating brush (1) is clearly defined, and the apron (26) with the side plate has a gap height of about 1 mm above the bottom surface (14).

[0092] FIG. 3 illustrates the position of the structure on the soft surface where the drive wheel (33) and the auxiliary wheel (34) are submerged in the soft surface of the floor (14), thereby reducing the ground clearance of the robot vacuum cleaner. On the soft surface, the self-leveling structure suspended from the swing arm (27) slides into the body of the robot vacuum cleaner and rests on the sliding surface of the apron (26) and the rotating blade (16) of the rotating brush (1) which is submerged about 1 mm below the carpet surface. Industrial applicability

[0093] The present invention can be used in a robot vacuum cleaner, in particular, which aims to supply air flowing rapidly directly from the spiral housing of the centrifugal fan of the robot vacuum cleaner to the bottom surface. Explanation of the symbols

[0094] 1: Rotary brush 2: Vacuum section 3: Housing 4: Collection container 5: Air filter 6: Inlet air duct 7: Centrifugal radial flow fan 8: Electric motor 9: Air outlet 10: Multi-channel straightener 11: Air duct 12: Multi-channel nozzle 12a: Upper section 12b: Lower section 13: Convex transfer area 14: Bottom 15: Line 16: Blade 17: High-speed pressurized airflow 18: Unwanted suction 19: Desired suction 20: Gap 21: Large object 22: Elastic coupling 23: Drive motor 24: Spiral housing 25: Raised rear edge 26: Apron 27: Pivot arm 28: Pin 29: Lug 30: Access section 31: Chamber 32: Wall 33: Drive wheel 34: Auxiliary wheel 35: Turbulence 36: Convex surface 37: Separation line 38: Outgoing pulsating air 39: Decelerated turbulence 40: Bar 41: Side plate 42: Fastener 43: Distance 44: Pulsation gap 45: Load 46: Impeller 47: Side duct 49: Input channel

Claims

Claim 1 A surface cleaning device comprises: a) a fan having an inlet side and an outlet side; b) a rotary brush including a plurality of rotary blades, wherein the rotary brush is located in a rotary brush chamber connected to the inlet side of the fan to form negative air pressure inside; c) a positive-pressure subsystem configured to receive pressurized air from the outlet side of the fan and to deliver a high-speed pressurized air flow over the surface through a flat nozzle in a forward direction toward the rotary blades; wherein a convex transfer surface having a convex curvature is disposed behind the flat nozzle, and the convex transfer surface, when viewed from the flat nozzle, first bends downward to a transfer line which is the lowest point of the convex transfer surface, and then bends upward to a raised discharge edge adjacent to the rotary brush chamber, and the convex transfer surface is such that when the high-speed pressurized air flow exits the flat nozzle, the high-speed pressurized air flow reaches the transfer line of the convex transfer surface, the A device configured and arranged within the device to move along a convex curvature, wherein at that point, airflow flows tangentially to the surface to be cleaned, and a change in static pressure acting on the high-speed pressurized airflow by the convex curvature of the convex transfer surface causes the airflow to flow along the surface to be cleaned in a forward direction toward the rotating blade. Claim 2 The apparatus according to claim 1, wherein the outlet of the flat nozzle further comprises an apron disposed at an outlet facing the forward direction of the high-speed pressurized air flow to restrict the penetration of ambient air into the convex transfer surface, the flat nozzle is a multi-channel nozzle disposed between the convex transfer surface and the apron, the multi-channel nozzle has an orifice inclined at 20 to 60 degrees from the surface to be cleaned, and the gap height between the transfer line of the convex transfer surface and the surface to be cleaned is in the range of 1 to 8 mm. Claim 3 A device according to paragraph 2, wherein the fan is a centrifugal fan housed within a spiral housing, and the flat nozzle is continuously connected to the spiral housing or at least its side duct by a multi-channel air flow straightener, the multi-channel air flow straightener has a plurality of channels connected to a system of individual air ducts, and the individual air ducts terminate at the inlet of the multi-channel nozzle. Claim 4 A device according to paragraph 3, wherein the multi-channel nozzle has a cross-sectional area that decreases between the opening of an individual air duct and the opening of the multi-channel nozzle. Claim 5 A device according to paragraph 3, wherein the rotary brush chamber is housed within a housing and connected to a collection container by an elastic coupling. Claim 6 A device according to paragraph 2, wherein the apron is rounded toward the surface to be cleaned as it moves away from the opening of the multi-channel nozzle, and the apron has a maximum gap height in the range of 0.5 to 2 mm from the surface to be cleaned, and the gap height of the apron is smaller than the gap height of the convex transfer surface. Claim 7 A device according to claim 1, wherein the raised discharge edge of the convex transfer surface forms the lowest edge of the rotating brush chamber. Claim 8 A device according to claim 1, wherein the rotary brush chamber is disposed between a first air duct connected to a collection chamber and a second air duct containing a high-speed pressurized air flow passing through the flat nozzle. Claim 9 A device according to claim 8, wherein the second air duct has one or more outlets, and the sum of the cross-sectional areas of the one or more outlets is 3 to 40% of the cross-sectional area of ​​the first air duct. Claim 10 An apparatus according to claim 8, wherein the high-speed pressurized air flow of air flowing toward the rotating brush through the flat nozzle includes a laminar flow of overpressure air, and the laminar flow of overpressure air is introduced into the rotating brush chamber and collides with a plurality of rotating blades of the rotating brush to induce turbulence and deceleration of the overpressure air. Claim 11 A device according to claim 1, wherein the device comprises a robot vacuum cleaner structure, and the rotary brush chamber and the flat nozzle are suspended from a plurality of parallel pivot arms mounted on pins rotatably mounted on a lug fixed to the robot vacuum cleaner structure. Claim 12 A device according to claim 1, wherein the fan is a centrifugal fan, and the device comprises a flat supply channel or at least one side supply channel disposed between the flat nozzle and the centrifugal fan. Claim 13 The device according to claim 1, wherein the device comprises a collection container fluidly connected between the rotating brush chamber and the fan.

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