EP1731074B1 - Vacuum cleaner - Google Patents

Abstract

The device has an electric motor (1), a suction channel (4), a pressure channel (5) and an auxiliary air channel (6) that is opened depending on the temperature in the pressure channel. An actuator element (8) for opening the auxiliary air channel is activated electrically. An electrically operated bimetallic or magnetic actuator element can be provided.

Description

The invention relates to a vacuum cleaner with an electric motor, a suction channel, a pressure channel and a secondary air channel, wherein an opening of the secondary air channel takes place in dependence on the temperature in the pressure channel, wherein further a pressure detection takes place in the suction air channel.

The performance of vacuum cleaners with the aim of maximizing dust pickup, especially on hard floors and low-pile carpets, continues to increase. However, even at high-pile carpets, the sliding force increases to high values with these high air flows. There are known in this regard solutions in which automatic positions are provided, which regulate the power consumption of the motor depending on the negative pressure in the device. With ever increasing recording power of vacuum cleaners and the cost of cooling the motor in the event that the device or the dust filter clogged and thereby the suction air flow, which usually also the cooling, eg. The electric motor takes over, is too low. In the known automatic devices, the negative pressure is usually tapped in the area behind the filter chamber. For deep-pile carpets, the negative pressure in the device increases. If a certain threshold is exceeded, electronically the recording power is lowered. The disadvantage is that this power reduction - and also the automatic increase of the power - leads to irritation for the user.

From the US 3,936,282 A a temperature-controlled valve for opening a secondary air line is known.

Based on the above-described context, the invention is based on the object of specifying a vacuum cleaner with an effective adaptation to different suction conditions, wherein as little irritation as possible should occur to the user.

The abovementioned disadvantages are counteracted by the invention in that an opening of the secondary air channel takes place with combined consideration of a temperature value, for example the temperature in the pressure channel, the volume flow in the suction or pressure channel and the pressure drop across the filter chamber. As a result of the solution according to the invention, the input power of the electric motor is not changed, as is known in the state of the art, but selectively controlled by an actuator for opening the secondary air duct, preferably by means of a electrical activation of the actuator. Here, this actuator may be a servo motor for continuously opening a secondary air duct flap. In addition, bi-metal, magnetic, piezoelectric or electro-chemical actuators are conceivable. The signal for the actuator is derived from a map, which is stored in a microcontroller. This map is preferably determined by the negative pressure behind the filter chamber, the negative pressure in front of the filter chamber, the temperature at vulnerable components and optionally by the user influenced thresholds. It can further be provided that a volumetric flow meter is arranged in the suction channel. In addition, it proves to be advantageous that in the suction channel in front of and behind the filter chamber, a pressure gauge is arranged, which may further be provided that the negative pressure in the suction channel is used independently to evaluate the pressure drop across the filter chamber for opening the secondary air passage. In addition, it proves to be advantageous that the measured negative pressure is compared with the power setting of the electric motor and / or with an attachment. From the data obtained, the pushing force of the attachment from the pressure in front of the filter chamber, the degree of filling of the filter chamber from the pressure drop at the same and the temperature load of vulnerable components, such as. The electric motor, determine via temperature sensors and the map the optimal opening of the secondary air duct calculate. It follows that the user always has the optimum suction power available for all floor coverings without the sliding force becoming too high. At the same time, the protection of the device against overheating is ensured. Irritations of the user due to audible fluctuating power consumption are excluded by the inventive solution. The suction power is regulated according to the invention by opening the secondary air duct, wherein the speed of the electric motor remains approximately the same. By detecting the temperature by means of sensors protection against damage caused by overheating of the components to be protected, for example. In a blockage, achieved. If a stored temperature limit value is reached or exceeded, a signal for opening the secondary air duct takes place. In addition, the Filterfüllgrad is detected by means of the pressure drop across the filter chamber, in which case a signal for electrical, mechanical, optical or acoustic display for changing the filter takes place when a stored limit value is reached. As mentioned, the volume flow is preferably measured in the suction channel. In the known state of the art, the pressure drop across the filter chamber depends inter alia on the volume flow, which has the disadvantage that a correct display is possible only at a certain volume flow, ie at a certain power position and at a certain attachment and operating state. By knowing the volume flow, the absolute obstruction of the filter chamber can be calculated and displayed in the solution according to the invention, this independent of the operating state, ie the power position of the electric motor and the type of attachment. The calculation is carried out via a map stored in a microcontroller. High sliding forces of the nozzle or other attachments are coupled to high negative pressures in the suction paths in front of the filter chamber. If the value for the negative pressure upstream of the filter chamber exceeds a preset limit value, a corresponding actuating signal for opening the secondary air channel is generated, whereupon the pushing force drops. In a header detection this can be done individually for each header at different Limit values are made. By integrating the volume flow, the total quantity delivered is determined. This value is compared to a preset value. If this value is exceeded, a signal is generated to change further filters, for example odor filters or superfine filters. When changing the filter, the integrator is reset to zero. If the user has set an operating state in which the actuator of the secondary air duct is open and / or the power controller of the electric motor is not set to maximum power, so can the increasing filling of the filter chamber and the resulting decrease in the suction power can be compensated by the present signals a corresponding closing of the secondary air duct. If the latter is closed and the device is not in the maximum power position, then the user can be shown to switch to a higher power level. It is also conceivable to let this increase in the power level take place automatically, the values to be taken into account being derived from the characteristic map.

• Fig. 1 eine schematische Darstellung eines Elektromotors mit einem Saugkanal, einem Druckkanal und einem Nebenluftkanal für einen Staubsauger;
• Fig. 2 eine der Fig. 1 entsprechende Darstellung;
• Fig. 3 eine weitere der Fig. 1 entsprechende Darstellung;
• Fig. 4 eine Ausführungsform der Erfindung.

Hereinafter, an embodiment of the invention with reference to the accompanying drawings is shown in detail. The Fig. 1-3 the drawing show embodiments according to the invention; These serve only for a better understanding of the actual invention. It shows:

• Fig. 1 a schematic representation of an electric motor with a suction channel, a pressure channel and a secondary air duct for a vacuum cleaner;
• Fig. 2 one of the Fig. 1 corresponding representation;
• Fig. 3 another one Fig. 1 corresponding representation;
• Fig. 4 an embodiment of the invention.

Shown and described is first with reference to Fig. 1 an electric motor 1 for a vacuum cleaner, not shown, to which electric motor 1 a driven by this impeller 2 is arranged. The blower unit formed thereby is provided with the numeral 3.

In the suction direction r, the blower unit 3 is a suction channel 4 and behind the blower unit 3, a suction channel 5 is arranged.

In the suction channel 4, that is, in the suction direction r in front of the blower unit 3, a secondary air channel 6 opens, the suction channel side opening 7 by means of an actuator 8 in a basic position according to Fig. 1 is closed.

However, blockages, however, can lead to such a reduction of the suction air flow that sufficient cooling of the electric motor 1 is no longer present. In order here to protect the electric motor from damage due to overheating, the temperature in the suction flow direction r behind the electric motor 1, ie in the region of the pressure channel 5 by means of a temperature sensor 9, for example. In the form of an NTC detected. The determined temperature value is compared in a control / evaluation unit 10 with a predetermined actual value. Exceeds the determined temperature a predetermined setpoint value, a signal for opening the secondary air duct is generated.

The temperature detection can be done by measuring the body temperature or by measuring the Saugstromluft temperature in the immediate vicinity of the electric motor 1 or other components to be protected. Further components endangered by high temperatures may be, for example, filters, plastic housing parts or even electronic components. The transmitter in the control / evaluation unit 10 may be constructed discretely or be designed in the form of a microcontroller, wherein a limit value for generating a control signal for opening the secondary air duct 6 may be preset or may be present as a variable value.

The opening 7 of the secondary air channel 6 can basically be arranged arbitrarily on the negative pressure side of the electric motor 1 in the region of the suction channel 4, but preferably an arrangement is selected behind a motor protection filter.

The opening of the secondary air duct 6 first closing actuator 8 is electrically activated according to the invention, which also spatially remote, formed by actuator 8 and secondary air duct opening 7 valves are controlled.

In the illustrated vacuum cleaner, the actuator 8 is provided in the form of a bi-metal actuator 11 which is electrically heated when the limit temperature is exceeded until it deforms to release the secondary air duct opening 7 (see dash-dotted representation in FIG Fig. 1 ). If the temperature drops due to the cooling air sucked in via the secondary air duct 6 again below the limit, the heater 12 des'Bi-metal actuator 11 is turned off, so that a provision of the actuator takes place to close the opening 7.

As an alternative to the illustrated actuator 8, it is also conceivable to provide a solenoid actuator which is electrically actuated when the limit temperature is exceeded and the secondary air duct opening 7 releases. In addition, piezoelectric elements or electro-chemical actuators as actuators are conceivable.

In Fig. 2 is another vacuum cleaner shown in which via a pressure sensor 25 in the suction channel 4 of the present pressure is measured and evaluated in a control / evaluation unit 10. About the latter, the actuator 8 is electrically driven to open the secondary air duct 6 from a predetermined limit. Shown here, however, are solutions of the actuator 8 according to the first embodiment, ie in the form of a bi-metal actuator 11, a solenoid actuator or a Actuator in the form of a piezoelectric element or an electro-chemical actuator.

In the vacuum cleaner according to Fig. 3 To protect against overheating of the electric motor 1, the temperature in the flow direction r behind the same, ie in the pressure channel 5, detected by means of an electronic temperature sensor 9. When a suitably defined temperature limit is exceeded, cooling secondary air is supplied by a, the Nebenluftkanal- Opening 7 occlusive actuator 8 is opened under pressure control. The switching point of the actuator 8, ie the necessary negative pressure at which an opening is made is so high that this does not affect regular applications. In general, opening takes place at higher negative pressure values. However, if the vacuum cleaner operated at a low power position, so there is a risk that the electric motor overheats because in this low power level, the switching threshold of the actuator 8 is not reached and thus does not open to flow cooling secondary air to last sen.

In order to avoid damage, secondary air must be supplied. If the temperature limit value is reached in a small power stage of the electric motor, then the vacuum-controlled actuator 8 is opened against the spring force of a spring 30 acting on the actuator 8 in the closed position, this being due to the fact that the electric motor 1 is controlled via the control / evaluation Unit 10 is spent in a power level at which sufficient negative pressure is generated to exceed the switching threshold of the actuator 8.

Fig. 4 shows an embodiment of the invention in which an opening of the secondary air duct 6 takes place with combined consideration of a temperature value in the pressure channel 5 for detecting the temperature of the electric motor 1, the volume flow in the suction channel 4 and the pressure drop across a filter chamber 15.

For detecting the pressure drop across the filter chamber 15, pressure sensors 16, 17 are provided in the suction channel 4 in front of and behind the filter chamber 15, the pressure sensor 17 behind the filter chamber 15 and a volumetric flow meter 18 are placed in the flow direction r in front of the opening 7 of the secondary air duct 6.

In addition, the negative pressure in the suction channel 4 is used independently of the evaluation of the pressure drop across the filter chamber 15 via the pressure sensor 16.

The values acquired via the sensors 9, 16, 17 and 18 are fed to a control / evaluation unit 10 in the form of a microcontroller and compared there with a stored characteristic map. As a further parameter for the evaluation of the signals serve the adjustment of, the electric motor 1 regulating power controller (arrow 19) and optionally the signal of a header detection (arrow 20).

From the value measured by the pressure sensor 16 in front of the filter chamber 15, the pushing force of the attachment can be determined. If the value for the negative pressure in front of the filter chamber 15 exceeds a preset limit, then a corresponding actuating signal (arrow 21) for opening the actuator 8, which in the form of a servomotor, a bi-metal actuator, a solenoid actuator or in the form a piezoelectric element or an electro-chemical actuator can be formed, generated, whereupon the pushing force decreases. If an attachment detection (arrow 20) is present, this can be done individually for each attachment at different limits.

By integrating a volume flow determination, the total volume of air delivered is determined. This value is compared to a preset value. If this value is exceeded, for example, a signal for changing the odor filter or superfine filter is generated (Arrow 22). When the filter is changed, the integrator is reset to zero.

About the determined pressure drop across the filter chamber 15, the level of the filter chamber is to be determined. If the pressure drop reaches a stored value, a signal (arrow 23) is generated to indicate the required filter change. This display can be done electrically, mechanically, visually or acoustically.
By knowing the volume flow determined by means of the volume flow meter 18, the absolute blockage of the filter chamber 15 can be calculated and displayed, regardless of the operating state, ie of the power position of the electric motor 1 and type of attachment. The calculation is made using the stored map in the control / evaluation unit.

If the user has set an operating state in which the actuator 8 is open and / or the power controller is not set to a maximum position, then the increasing filling of the filter chamber 15 and the resulting decrease in the suction power can be compensated by a corresponding one with the present signals Moving the actuator 8. If this is closed and the electric motor 1 is not operated in the maximum position, then the user can be indicated to switch to a higher power level. Such a power upshift can also be done automatically via the map.

In order to protect vulnerable components, such as. The electric motor 1, from damage due to overheating due to clogging, etc., via the temperature sensor 9 in response to a stored limit Signal (arrow 21) to open the secondary air duct 6 generated.

By the in Fig. 4 illustrated solution according to the invention is achieved via the use of a map a steady adjustment of the optimum suction power. This adjustment of the suction power via a, formed from the actuator 8 and the secondary air duct opening 7 valve. In addition, all sizes are available to determine the pressure loss of the filled filter chamber 15 and to control the Saugleistungsanzeige / filter change indicator.

Claims (7)

1. Vacuum cleaner having an electric motor (1), a suction channel (4), a pressure channel (5) and an auxiliary air channel (6), the auxiliary air channel (6) being opened as a function of the temperature in the pressure channel (5), furthermore pressure being detected in the suction channel, characterised in that the auxiliary air channel (6) is opened in combined consideration of a temperature value, for example the temperature in the pressure channel (5), the volumetric flow in the suction (4) or pressure (5) channel, and the pressure drop at the filter chamber (15).
2. Vacuum cleaner according to claim 1, characterised in that in the suction channel (4) is arranged a volumetric flow meter (18).
3. Vacuum cleaner according to either of claims 1 or 2, characterised in that in the suction channel (4) in front of and behind the filter chamber (15) is arranged a pressure gauge (18).
4. Vacuum cleaner according to any of claims 1 to 3, characterised in that the partial pressure in the suction channel (4) is used to open the auxiliary air channel (6), independently of evaluation of the pressure drop at the filter chamber (15).
5. Vacuum cleaner according to any of claims 1 to 4, characterised in that the measured partial pressure is coordinated with the power setting of the electric motor (1) and/or with an attachment.
6. Vacuum cleaner according to any of claims 1 to 5, characterised in that the volumetric flow measurement can be integrated.
7. Vacuum cleaner according to claim 6, characterised in that the integrated value of volumetric flow measurement is used to generate a signal as a function of a reference value.

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