EP4296430A1 - Soil milling machine and method for operating a dust extraction device of a soil milling machine - Google Patents

Abstract

The invention relates to a soil milling machine, in particular a road milling machine, recycler or stabilizer, for processing a soil in or against a working direction, comprising a machine frame carried by driving devices with a drive motor, a milling drum rotatably mounted in a milling drum box arranged on the machine frame for removing soil material and a suction device for Suction of dust-containing air from the milling drum box and/or an area of a conveying channel of the milled material, comprising a suction fan and at least one suction channel running from the milling drum box to the suction fan. Furthermore, the invention also relates to a method for operating a dust extraction device of a ground milling machine.

Description

The invention relates to a soil milling machine, in particular a road milling machine, a recycler or a stabilizer, for processing a soil in or against a working direction. In addition, the invention also relates to a method for operating a dust extraction device of a ground milling machine.

Generic ground milling machines are used in road and path construction and are, for example, in EP3225738B1 described. They have a machine frame supported by driving devices with a drive motor, which usually provides the drive energy required for driving and working operations. The driving devices can be, for example, chain drives or wheels. The drive motor can be, for example, an internal combustion engine, for example a diesel internal combustion engine. Such machines are preferably designed to be self-propelled and move on their own initiative over the ground to be worked. The central working device of generic ground milling machines is a milling drum that is rotatably mounted in a milling drum box mounted on the machine frame for removing soil material. The milling drum can have a hollow cylindrical base body, on the outer surface of which a large number of milling tools, for example milling cutters, are mounted radially in relation to the outer surface. During operation, the milling drum rotates about an axis of rotation that is usually horizontal and transverse to the working direction of the ground milling machine. The milling tools are driven into the ground to be removed by lowering and moving the ground milling machine in a travel or working direction, whereby it is milled to a milling depth. The milling drum box surrounds the milling drum like a hood and is designed to be open towards the ground, so that the milling drum can protrude downwards over the lower edge of the milling drum box for ground engagement. The milling drum box can have wall elements that are height-adjustable relative to the milling drum, such as a scraper shield, one or more side shields and/or a Include front shield, which enables the lower sealing edge of the milling drum box to be adapted to different milling conditions, in particular with regard to the milling depth and / or the ground conditions. The removed milled material collected in the milling drum box is typically transported from there to a milled material conveyor through an ejection opening in the milling drum box and guided from the milled material conveyor to a discharge point. This is also referred to below as the conveying route of the milled material. The milled material conveying device can comprise one or more conveyor belts arranged in a row. At the discharge point of the milled material conveyor, it throws the soil material onto the loading area of a transport vehicle, for example a truck, for further removal of the milled material.

Milling and conveying or transporting the soil material can result in a lot of dust being generated during the milling operation of the soil milling machine. The resulting dust can impair the visibility and/or health of people on and near the ground milling machine. Air in which these dusts are dispersed is hereinafter referred to as dust-containing air. In order to keep the discharge of dust into the external environment of the ground milling machine as low as possible, it is already known to equip generic ground milling machines with a suction device or dust extraction device. Depending on the embodiment, the task of this dust extraction device is to control the dust emission, in particular in the area of the milling drum box and/or in the area of the milled material conveying section, and either to direct it to certain points on the ground milling machine, for example to a milled material transfer point of the milled material conveyor to a transport vehicle, and/or to intercept the resulting dust in order to reduce the overall dust emissions of the ground milling machine. E-dust and A-dust, as defined in DIN EN 481, are particularly relevant. For this purpose, the dust extraction device or suction device typically comprises at least one suction fan and a suction channel connected in a flow-connected manner to the suction fan. The suction fan, which has a suction side and a blow-out side, thus generates a negative pressure on the suction side and ultimately a suction of air in the suction channel. The suction channel in turn refers to an air-permeable connection between the milling drum box interior and/or an area of the milled material conveying device and the suction fan. For this purpose, the suction channel can be designed as a line/channel that is at least partially separate from the milled material conveying device, but can also at least partially form a common space with the milled material conveying device. The milled material and the suction channel or the dust-containing air conveyed in the suction channel do not necessarily have to be spatially separated throughout, but can, at least partially, also be guided through the same spatial compartment. In particular due to the fact that the milled material conveying device in generic ground milling machines is often surrounded by a housing transversely to the conveying direction of the milled material and thus runs in a channel-like overall structure, it is possible that at least parts or sections of the milled material conveying device are also part of the suction channel at the same time. It is essential for the design of the suction channel that ultimately the suction generated by the suction fan can ideally reach the milling drum housing, in particular its interior, and / or a part of the milled material conveying section of the milled material conveying device, so that as a result dust-containing air is removed from the interior of the milling drum box and/or the conveying section of the milled material conveying device and can be conveyed via the suction channel up to the suction fan and downstream to an outlet point. Upstream and/or downstream of the suction fan, the extracted dust-containing air can also be passed through a dust reduction device or dust separation device, for example a filter device, such as an electric and/or fabric and/or cyclone filter, and/or a water sprinkler device. Generic ground milling machines with dust extraction devices are, for example, from the publications DE102012022879B4 and EP3225738B1 known to the applicant.

Even if a number of measures are already known for reducing dust pollution, in particular for the operator, of a generic ground milling machine due to dust generated in the milling process, the operating method is often still not optimal. Known suction devices can only be activated and deactivated regularly. However, the operating conditions for the ground milling machine change frequently. This can, for example, concern the individual operating conditions on site depending on the weather and soil material, or also the current operating configuration of the ground milling machine itself. Here, different milling depths, milling work that only affects part of the width of the milling drum, different positional conditions of the elements sealing the milling drum box downwards (front shield, scrapers, side shields, etc.), lifting positions of lifting devices of the driving devices, pivoting and/or tilting positions of parts of the milled material conveying device, different widths of the milling drum arranged in the milling drum box, etc. create extremely different operating conditions for the ground milling machine, especially in milling operation. This means that the extraction device is regularly configured in such a way that the suction that can be generated using the extraction fan is reliably sufficient across the entire range of uses and operations in order to always ensure actual extraction of dust-containing air from the milling drum box under all of the above-mentioned conditions. For this reason, the dust extraction device is regularly designed in such a way that the suction acting on the milling drum box and generated by the suction fan is very high, in the hope of always having sufficient suction for dust extraction under a wide variety of operating conditions.

However, this can be disadvantageous in many ways. In particular, when using an electrostatic filter/separator arranged in the area of the suction channel, it is advantageous if the flow velocities occurring in the electrostatic filter/separator are rather small, in particular to enable separation of relatively larger dust particles and/or the required separation distance to be as compact as possible to keep. In addition, a comparatively high negative pressure applied to the milling drum box can cause a kind of vacuum cleaner effect in the external environment around the milling drum box, especially in the area of its lower edge. In this way, additional dust or small particles present outside the milling drum box are also sucked in via the dust that is already generated during the milling process, which can, for example, significantly adversely affect the separation performance of filter devices arranged in the suction channel. In addition, a maximum filter capacity of the filter elements used can be achieved comparatively early, since naturally, at high suction pressure and / or suction speeds, comparatively larger particles are sucked in, enter the suction channel and are conveyed to the corresponding filter element.

Proceeding from this, it is therefore the object of the invention to provide a way to improve the operation of a suction device for extracting dust-containing air from the milling drum box of a ground milling machine.

The problem is solved with a ground milling machine and a method according to the independent claims. Preferred further developments are specified in the dependent claims.

A generic ground milling machine, in particular a road milling machine, recycler or stabilizer, comprises a machine frame supported by driving devices with a drive motor and a milling roller rotatably mounted in a milling roller box arranged on the machine frame for removing soil material. The driving devices can be connected to the machine frame via height-adjustable lifting devices, for example lifting columns. During milling operation, dust can be generated due to the milling process and/or the transport process of the milled material within the ground milling machine. In order to reduce the resulting dust, there is a suction device for extracting dust-containing air from the milling roller box and/or an area of a conveyor channel or a milled material conveying section of the milled material. Part of the suction device is at least one suction fan with which the suction required for suction can be generated. For this purpose, the suction fan can have at least one fan drive, in particular a fan motor, which drives, for example, at least one air-promoting element, for example an impeller. The extraction fan can be used on the ground milling machine This creates a suction and thus a directed air flow through which dust-containing air can be sucked in. On the side upstream of the suction fan, a negative pressure and thus the suction is generated when the suction fan is in operation by conveying the air. In order to be able to extend the resulting suction effect to one of the points relevant to the formation of dust in the milling process, in particular the interior of the milling roller box and/or an area in the conveying channel of the milled material, for the extraction of dust-containing air, part of the suction device is also a suction channel runs from the milling drum box and/or an area in the conveying channel of the milled material to the suction fan. The suction channel thus constructively designates those areas of the ground milling machine which, when working together, enable the negative pressure or suction generated by the suction fan to act up to the milling drum box and in particular up to its interior and/or an area of the conveying channel of the milled material, so that then due to Due to the air conveying effect created by the suction fan, a negative pressure is also present in the interior of the milling roller box and/or in an area of the conveying channel of the milled material during suction or can be generated by the suction fan. It is understood that the suction channel does not necessarily have to have a substantially hermetically sealed design, but in practical use there may be at least local leaks in the suction channel between the milling drum box interior and/or the conveying channel and the suction fan, for example in the area of a transfer point from the milling drum box interior and a conveyor belt, between conveyor belts following one another in the conveying direction, the milled material transfer point from the milling roller box to the conveyor device, etc. However, this can be countered in a manner known per se by sufficient suction power of the suction device. A blow-out channel can also be connected to the suction channel downstream of the suction device, via which the air that has been sucked out and passed through the suction fan can be blown out of the road milling machine in an area. This can be, for example, the end of a conveyor belt or another area of the road milling machine.

It is now essential that the suction device according to the invention comprises a control device. The control device is designed in such a way that the suction power of the suction device available for the suction of dust-containing air from the milling roller box and/or the area of the conveying channel of the milled material can be changed, in particular regulated. In other words, the control device allows a, in particular regulated, change in the operation of the suction device in such a way that the volume of air available per unit of time for extracting dust-containing air from the milling drum box and/or an area of the conveying channel of the milled material can be changed. With the help of the control device, for example, the suction device can be controlled with regard to its current dust delivery performance or suction power (for example delivery volume of air per unit of time) can be adjustable and operated between at least two or more performance levels and / or within a performance range. In this context, it is noted as a precautionary measure that switching off or deactivating the suction device or in particular just the suction fan itself, for example in such a way that a fan wheel no longer rotates, is explicitly not to be understood as "operation of the suction device". By definition, “operation of the suction device” occurs when the suction fan also delivers air. According to the invention, the suction devices can be varied in suction mode, for example, between at least two or more performance levels or within a performance range in which, under constant operating conditions, they convey sometimes more and sometimes less air per unit of time or from the milling roller box and / or the area of the conveying channel of the milled material sucks off. The control device is therefore designed in such a way that, for example, the suction fan can be adjusted, in particular in a controlled manner, at at least two different speeds or within a speed range. The higher the speed of the suction fan, the more air is conveyed through this suction fan per unit of time and the higher the suction performance can be. This means that the suction power currently available during operation of the ground milling machine is variable by the control device, which enables improved coordination of the current suction power available for extracting dust-containing air with regard to the existing operating conditions of the ground milling machine.

Such an adjustment of the suction power available for the suction of dust-containing air can be done manually, in particular by a direct or indirect controlled change in the speed of a drive motor of the suction fan using a suitable input device, for example a keyboard, of the control device. Specifically, it can therefore be provided, for example, that an operator chooses between at least two speeds of the suction fan and/or within a speed range, for example by means of a corresponding manual input. Additionally or alternatively, a variable dependent on the speed of the suction fan can also be specified, for example a suction, a negative pressure, a pressure difference, etc. The control device can include a control device which then adjusts the operation of the suction fan, in particular its speed, within a specified range or regulates. It is therefore particularly important here that control and/or regulation takes place by influencing the operation of the suction fan itself, in particular its speed and/or impeller position. Additionally or alternatively, a control, in particular regulation, of the suction power of the suction device on or in the milling drum box and/or in an area of the conveying channel can also be done by influencing the design or design of the suction channel of the suction device by the control device in order to vary the suction power available for the suction of dust-containing air. For this purpose, the suction device can, for example, comprise suction openings and/or channel sections that can be varied by the control device with regard to their opening cross-section, via which or through which additional air is sucked in to the suction device to a variable extent. For this purpose, it can be provided that, for example, within a section of the suction channel there is a device controlled by the control device, controlled or manually, for example one or more flaps, by adjusting which the flow cross section of the suction channel is variable, in particular enlarged and / or reduced can. Additionally or alternatively, elements controlled by the control device can be present, via which ambient air can be sucked into the suction channel in addition to the dust-containing air. In this embodiment variant, the area up to which the suction effect generated by the suction fan extends is variable, so that air that does not contain dust can also be sucked in, so that the suction proportion available for the suction of dust-containing air is reduced. Such a supply air device can be designed, for example, in the form of adjustable closure slats and/or flaps in a wall of the suction duct that cover an air passage opening. By providing the control device, it is possible for the suction power of the suction device to be adapted to different working conditions, for example with regard to the current working and/or environmental conditions and/or machine configuration, and/or with regard to a suction result, as required. How the current need can be determined and/or according to which criteria the control device can even regulate automatically can vary and will be described in more detail below by way of example. It is therefore first of all important that the suction device in the activated, ie suctioning, state can be operated by the control unit on at least two power levels and/or variably within a performance range with regard to the suction power available for the suction of dust-containing air.

In principle, it is possible for the current demand for suction power to be set by the control device based on one or more machine settings or machine configurations. For example, it can be provided that the current suction power, continuously or incrementally, within a controllable range of the suction device by the control device depending on, for example, the current milling depth, the relative position of a side plate, a hold-down device, one or more driving devices, a conveyor device and / or another ground contact element relative to the machine frame or to a fixed reference point, the current machine inclination relative to the ground, be it with regard to the transverse and / or longitudinal inclination, the pivoting position of a side plate relative to a milling drum box or to the machine frame, the Width of a milling drum, the stocking and / or the stocking density of the milling drum with milling tools, etc., is regulated. For one or more of these operating parameters, corresponding maps or comparable data sets can, for example, be stored in a machine control or similar. What is crucial is that ideally at least one detection device is present for the respective machine setting or machine configuration, which is designed for direct and/or indirect detection of an actual value of the operating parameter(s). Based on this or these recorded actual values, the control device then regulates the operation of the suction device to the desired setting. This preferred development is therefore characterized in that the suction device and its control device are designed in such a way that the control takes place depending on a setting position and/or setting change and/or an operating state of a machine element, in particular during a milling process. This type of regulation/control can also be referred to as configuration mode, since the operation of the suction device depends on one or more machine configurations. The respective machine configuration can be entered manually and/or determined using suitable sensors.

In addition or alternatively, it is also possible for the control device to regulate the suction power to determine or take into account effective parameters of the suction itself, i.e. parameters or variables that are directly or indirectly attributable to the effect of the air suction, and to use them to regulate the suction power. For this purpose, it can be provided that the suction device comprises a sensor device which determines and/or monitors one or more variables, in particular actual values of one or more operating parameters of the suction device and/or operating parameters of the ground milling machine influenced by this, which influence the for the suction power available for the extraction of dust-containing air and/or depend on it. For this purpose, the sensor device can have a data and/or signal transmission connection with the control device, wirelessly and/or wired, so that the control device can determine the suction power of the suction device and/or its operating state based on the determined and/or monitored data and/or signals from the sensor device regulates. It is therefore possible for the control device to be designed in such a way that it regulates the suction power available for the suction of air from the milling drum box depending on an effective variable of the suction device. In other words, in this embodiment it is provided that the suction power of the suction device regulated by the control device monitors and takes into account one or more effects or consequences of the suction work performed by the suction device via the sensor device, and the regulation is therefore carried out depending on this. Effects or effects of the suction work can, for example, be a flow speed, a flow rate, a dust development that occurs or, ideally, does not occur or emerges, a pressure, in particular a negative pressure compared to the external environment, a pressure difference, a suction force and the like.

In addition or as an alternative, it is particularly advantageous if the suction device and its control device are designed in such a way that the suction power is regulated as a function of a current dust emission, in particular a dust emission from the milling drum box into the external environment. In this case, the control device is particularly preferably designed in such a way that when dust or dust-containing air emerges from the milling drum box, the suction power for the suction of air from the milling drum box is increased, for example by increasing a fan wheel speed of the suction fan. Additionally or alternatively, it can also be provided that if dust-containing air does not escape from the milling roller box, the suction power is reduced, for example by reducing the fan speed of the suction fan. In this context, it can also be provided in particular that a minimum speed of the suction fan and/or a minimum value of another effective variable is not exceeded.

In order to determine the information that can be used for regulation by the control device, it can be provided that the suction device comprises a sensor device. The sensor device or the sensors of the sensor device itself do not have to form a structurally coherent unit with other elements of the suction device. It is essential that the sensor device has at least one sensor which supplies a sensor value representing an actual value to the control device, which only uses it for display to the operator but preferably in particular for regulating the suction power available for the suction of dust-containing air can. For this purpose, the sensor device can be designed in such a way that it determines the current value and/or a measured variable correlating therewith of an effective variable of the suction device and/or a dust emission, which is in particular representative of the suction of dust-containing air from the milling drum box and/or the escape of There is dust from the milling drum box to the outside environment. This does not mean that a representative value for the extraction of dust-containing air from the milling drum box can only be determined if air laden with dust is actually extracted from the milling drum box. This value is also representative if, under the current operating conditions of the suction device, it can be assumed that air contaminated with dust would also be extracted from the milling drum box and/or an area of the conveying channel if dust were actually generated.

Specifically, the sensor device can, for example, be designed in such a way that an effective variable of the suction device determined by it has at least an air pressure within the milling drum box and/or within a region of the suction channel, in particular in relation to the conveying path of the milled material between the milling drum box and the suction fan, and/or is an air pressure difference between an air pressure inside the milling drum box and/or within an area of a suction channel, in particular in relation to the conveying distance of the milled material between the milling drum box and the suction fan, and an air pressure outside the milling drum box and outside the suction device, in particular an ambient air pressure of the ground milling machine . These air pressure measurements can be used to determine whether there is a negative pressure in the milling drum box and/or within the respective area of the suction channel. This occurs in particular if there is a suction effect in the direction of the suction fan at the respective location. Additionally or alternatively, it is also possible for the sensor device to be designed in such a way that it determines an inflow direction of air into the interior of the milling drum box or, more generally, a flow direction of the air. It is also possible to determine a flow velocity. This (flow direction and/or flow velocity) can also be used to determine in which direction air is flowing or there is a suction effect at the measuring point of the sensor(s). Additionally or alternatively, a volume flow of air flowing into the interior of the milling drum box and/or into the area of the conveying channel, in particular from outside, can also be determined, which is ultimately a quantitative consideration of the current suction effect. It is understood that the above effective variables can be determined directly and/or in the form of a measurement variable that correlates with the respective effective variable. The control device can now preferably be designed in such a way that it controls the suction power available for the suction of dust-containing air, in particular a speed of a suction fan, in such a way that a negative pressure and/or suction exists, but is as low as possible. For this purpose, a minimum limit value that is not to be fallen below or exceeded, for example for a pressure difference, flow velocity, etc., can be stored in the control device.

The specific selection of the sensor or sensors used to detect an effective variable of the suction device can also vary. If, for example, air pressure is to be detected, an air pressure sensor, in particular an electronic one, can preferably be used. Here it is possible to carry out absolute and/or relative air pressure measurements. In particular, a preferred air pressure sensor can be designed based on MEMS. Additionally or alternatively, an air pressure difference sensor or differential pressure measurement sensor and/or a dynamic pressure measurement sensor can also be part of the sensor device. Additionally or alternatively, one or more volume flow measurement sensors, flow measurement sensors, in particular vane anemometers and/or flow direction measuring sensors can be used. What the above-mentioned sensors have in common is that they either directly or indirectly provide information about an air pressure or an air movement through the direct effect of the air on the respective sensor and thus provide a conclusion as to whether the currently available suction power is sufficient to extract air containing dust.

In addition or as an alternative to this, however, it can also be provided that the sensor device has a device for detecting dust, in particular moving dust-containing air. For this purpose, for example, a camera, in particular a digital camera and/or stereo camera, can be used. Furthermore, in this case it can be provided that the sensor device comprises suitable image processing software that is designed to determine dust-containing air or to identify dust in air in one or more camera recordings. This can be done specifically, for example, through image sharpness analyzes and/or through the identification of other phenomena that are characteristic of dust-containing air, for example through an image comparison, a video analysis, etc. Additionally or alternatively, a dust sensor or a dust detector can also be used and a preferably continuous one , Carry out real-time dust measurement. Such detectors are known, for example, under the trade names Microdust Pro CEL-712 or DustTrak II. In terms of its functional principle, a dust sensor can include a laser photometer with which a light scattering measurement is carried out to detect dust. Additionally or alternatively, an optical dust sensor, in particular a dust sensor (extinction or scattering) that works on a photometric measuring principle, can also be used. Other dust sensors/detectors can also be used here.

There is also a large scope for variation with regard to the location of the sensor(s) of the sensor device on the ground milling machine. It is important that there is ideally one or more arrangement points at which a meaningful sensor value determination for the ongoing suction operation during the ongoing milling operation is possible. The air pressure measurement, in particular the differential pressure measurement, can include a measurement of the outside ambient air pressure. It makes sense to arrange the air pressure sensor that can be used for this purpose, for example on the milling drum box. Alternatively, it can also be advantageous to arrange this air pressure sensor in the area of the rest of the ground milling machine, so that the sensor does not have to be connected separately when changing the milling drum box, for example. An air pressure sensor for determining an internal pressure, for example within the milling roller box and/or in an area of the conveying channel of the milled material and/or within the suction channel, is preferably arranged in such a way that neither milled material nor dust-containing air flow directly over the sensor, for example in order to reduce wear to reduce the sensor housing that may be present. Accordingly, blind hole-like measuring openings can be present for this purpose, which open into the milling roller box and/or the conveying channel of the milled material and/or the suction channel and at the other end of which the respective pressure sensor is arranged, so that there is a spatial connection with the same pressure conditions between the sensor and the measuring interior . An air pressure difference sensor, volume flow measurement sensor, flow measurement sensor and/or flow direction measurement sensor can, for example, be installed in a wall element of the milling drum box, the conveyor channel and/or the suction channel that delimits the respective interior space, so that air is sucked in from outside this respective room in the suction operation, in particular from the external environment, and through This opening flows past the respective sensor into the respective interior. The advantage here is that the air used for the measurement does not necessarily have to contain dust. However, the potential admixture of non-dust-containing air reduces the efficiency of the suction process somewhat, even if only marginally. It is therefore also possible to arrange one of these sensors directly in the suction channel itself, so that the extracted dust-containing air flows directly past the respective sensor. It is therefore essential for this type of sensors that they are positioned in the area of the suction effect of the suction device. With regard to the arrangement of the camera and/or the dust sensor, it is important that the camera's viewing direction is aligned in such a way that it captures an area in which dust from the milling drum box and/or the conveyor device and/or the suction channel towards the outside environment milling operation can occur. A particularly relevant area here is in particular the area of the lower edge of the milling drum box towards the ground and/or the area of the transfer opening in the milling drum box to a conveyor device. Accordingly, it can also be advantageous if the dust sensor is arranged at least near the lower edge of the milling drum box. This can also be, for example, on the underside of the machine frame, in particular between the front and/or rear driving devices. This area is generally also suitable for arranging the camera. It may be sufficient if only part of the lower edge is captured by such a camera.

It is possible for the control device to control and/or regulate the suction power available for the suction of dust-containing air depending on, for example, different machine configurations. This development of the invention is based on the basic idea that a change in machine settings and/or configurations can have an influence on how well or efficiently dust-containing air is removed from the milling drum box and/or the area of the conveying channel of the milled material at a certain suction capacity of the suction device is sucked off. Accordingly, for certain configurations of the ground milling machine, it may make sense to increase the suction capacity of the suction device to increase or decrease. This can be the case, for example, if one or more of the sealing elements of the milling drum box facing the ground, for example the side shields and/or a scraper shield, are not optimally aligned between the ground surface and the rest of the ground milling machine, for example due to tilting, unevenness in the floor a milling edge within the milling width, etc. In such operating situations, in order to maintain sufficient dust extraction, it can be advantageous compared to a conventional operating situation to change the suction power of the suction device, for example to increase it, among other things, to take into account a milling drum box that is comparatively less dense to the ground. In addition or alternatively, so-called fine milling work, for example, can result in significantly greater dust development compared to milling with comparatively large milling depths. In this case, it makes sense to aim for increased suction power of the suction device, for example at low milling depths. For example, a water saving mode can also be provided in which the amount of water released into the milling box during milling work is reduced, for example due to a low water tank level in the ground milling machine. Less water means that there is a tendency for increased dust to be produced. In this case too, it can make sense to increase the suction power to extract air containing dust in order to counteract the reduced water discharge to combat dust. In a preferred embodiment of the invention, the sensor device is therefore also designed in such a way that it determines the current value and/or a measured variable of a setting position and/or setting change and/or an operating state of at least one machine element, and that the control device for the Suction power available for suction of air from the milling drum box is controlled and/or regulated as a function of at least this determined setting position and/or setting change and/or this determined operating state. As a precautionary measure, it should be noted again that switching an exhaust fan off and on does not explicitly fall under a regulation of the suction power of the suction device available for the suction of air from the milling drum box and/or the area of the conveying channel of the milled material. In this context, it can thus be provided that the sensor device is designed to determine the setting position and/or the setting change of the at least one machine element, in particular to determine the stroke position and/or change in stroke position of a scraper shield of the milling drum box, in particular relative to the machine frame, to determine the Lifting and/or pivoting position and/or lifting and/or pivoting position change of at least one side plate of the milling drum box, in particular relative to the machine frame, to determine the actual milling width of a milling drum, to determine the milling depth, to determine the machine longitudinal and/or transverse inclination, to determine the pivot position and/or the operating state of a belt conveyor and/or to determine the stroke position of a hold-down device relative to the machine frame and/or to determine a tank fill level. Further additionally or alternatively, the sensor device for determining the operating state can, for example, be a device for determining whether a milling drum of the ground milling machine is driven and / or rotates about its axis of rotation and / or at what speed the milling drum rotates about its axis of rotation, a device for determining whether the milling drum is in milling mode and/or in active milling machine feed, a device for determining a milling depth, a device for determining whether a water sprinkler system that supplies water into the interior of the milling drum box and/or in the conveying area of the milled material within the ground milling machine and/ or in the area of a material discharge point, is activated or deactivated and/or how high the water discharge is per unit of time, a device for determining whether a particle filter device, in particular an electrical separator, is present and/or activated, a device for determining the operating status one or more driving devices and / or one or more elements associated with the drive train of at least one of the driving devices. It is understood that the above sensor values can be determined directly and/or in the form of a measurement variable that correlates with the respective position and/or change in position. What is essential for this preferred development is that the control device determines the suction power available for the suction of air from the milling drum box depending on at least one of these machine configurations detected and/or monitored by the sensor device, changes in machine settings and/or configurations and/or Controls and/or regulates operating states and/or changes in operating states.

The specific design of the dust extraction device and its design for changing the suction power available for the extraction of dust-containing air from the milling drum box can also vary. It is, for example, advantageous if the suction fan has a fan drive motor that is infinitely adjustable with respect to a drive speed and/or fan wheel speed, in particular within a speed range, which is controlled by the control device, in particular is regulated by the control device with regard to its target speed. It goes without saying that the blower drive motor has a suitable speed sensor for detecting the actual speed. The drive motor, in particular the fan drive motor, can in particular be an electrically, electrohydraulically or hydraulically driven drive motor. The fan drive motor, in particular a hydraulic or electric motor, is preferably driven in such a way that the drive power supplied to it, be it in the form of hydraulic or electrical energy per unit of time, can be varied by the control device, continuously and / or incrementally.

The dust extraction device can comprise a plurality of fan drive motors, each of which drives at least one fan wheel. It is then advantageous if the plurality of dust extraction devices and/or suction fans are at least partially arranged in parallel with respect to their flow guidance, so that air conveyed by them does not pass through several suction fans one after the other. In order to control/regulate the suction power available for extracting dust-containing air, it is then possible, for example, for individual of a large number of parallel-arranged suction units, in particular suction fans, to be switched on and off.

Additionally or alternatively, the dust extraction device can have an, in particular controllable, air inflow device, in particular comprising a supply air flap and/or slide that is variable with regard to its opening area or its flow cross section. As a result, the dust-containing air in the suction channel, for example non-dust-containing air, in particular from the external environment of the ground milling machine, can be mixed in, thereby ultimately reducing the suction power available for the suction of dust-containing air (i.e. the proportion of the air that can be used for the suction of dust-containing air Total suction performance of the suction device) can be influenced. Such an air inflow device can be arranged in particular in or on the suction channel in the area between the milling drum box and the suction fan. Additionally or alternatively, bypass suction of air is also possible. In this case, in addition to the suction channel, an additional suction channel is present, in particular in direct flow connection with the suction fan. In contrast to the previous embodiment, there is no mixing of the additionally sucked-in air with sucked-in dust-containing air upstream of the suction fan. Additionally or alternatively, elements can also be present in the suction channel with which the flow cross section within the suction channel can be changed and thus influence the suction power available for extracting dust-containing air.

The control device itself, if it regulates the operation of the suction device, can also be designed differently with regard to the control regime. It is preferred, for example, if the control device is designed in such a way that it regulates the suction power available for the suction of air from the milling drum box to a limit value that cannot be exceeded or fallen below. Additionally or alternatively, it can be provided that the control device is designed in such a way that it continuously adjusts the suction power available for the suction of air from the milling drum box a limit value range. However, it is also possible for an incremental or stepped control to take place, in particular in such a way that, in addition to a deactivated state of the suction device, it can switch between at least two suction powers generated by the suction device, in particular speeds of the suction fan. Additionally or alternatively, a control can be carried out to the effect that a flow rate and/or a flow rate range of a part of the suction channel running upstream of the suction device and/or the blow-out channel running downstream of the suction device is not exceeded and/or fallen below. This can be, for example, the flow speed of the extracted dust-containing air guided through this area, viewed in the direction of flow, in front of, in or behind a separation device for dust particles from the extracted dust-containing air, in particular an electric separator.

The control device can comprise a memory device with one or more characteristic maps on which the control is based, for example as described above. In addition or alternatively, it can also be provided that the control device includes a learning mode. In this mode, for example, in a specific operating situation of the ground milling machine, an operator can manually change or adjust the suction power available for extracting air from the milling drum box, for example by manipulating the speed of the suction fan, until a setup that is satisfactory to him is achieved. It can then be provided that the operator, based on this, adjusts the control device to a subsequent "control mode" in which the control device then controls the suction device, in particular the suction power available for the suction of dust-containing air, over the changes that occur during use regulates that the available suction power for dust-containing air selected in the learning mode is at least maintained and/or kept as constant as possible. Alternatively, a flow rate of a separation element, in particular an electrical separator, can also be monitored and set as a target value, in particular within a defined range, for regulating the suction device. In addition to or as an alternative to one or more manually defined target variables for the control, predefined operating modes can also be provided. In this context, the control device can, for example, be designed such that it maintains a defined negative pressure and/or a defined inflow velocity and/or a defined pressure difference between the internal pressure within the milling drum box or the suction duct and the external ambient pressure of the ground milling machine. This can be done, for example, in particular by controlling the speed of the suction fan. There can also be one or more factory default settings and/or setting modes may be provided. It is ideal if the control takes place in the sense of a limit value control so that no dust escapes into the outside environment. This can be done indirectly by setting a minimum internal negative pressure in the milling roller box and/or an area in the suction channel or directly by monitoring an actual current dust emission during operation of the ground milling machine, in particular using a dust sensor and/or at least one camera. Starting from this basic arrangement, it can now be provided in particular that the control device, for example, continuously or gradually lowers the value for the extraction of dust-containing air, starting from a starting value that experience has shown to be oversized, up to the point at which dust escapes from the milling drum box and / or from an interior area the suction channel occurs and/or dust escapes significantly. From the actual suction power then available, the suction power available for the suction of dust-containing air can be kept at this value or, preferably, increased again by a defined proportion in order to counteract the observed dust escape on the one hand, but on the other hand still keep the suction power at a level to be able to maintain a reduced level compared to the starting value.

A further aspect of the invention relates to a method for operating a suction device of a ground milling machine, in particular a ground milling machine according to the invention, for extracting dust-containing air from the milling drum box and/or an area of a conveying channel of the milled material. It is essential for the method according to the invention that the suction power available for the suction of air from the milling drum box can be changed, in particular in a controlled manner, with the aid of a control device. In particular during a milling operation, it is possible for the suction power available for the suction of dust-containing air to be controlled and/or regulated by the control device. This means that the suction power of the suction device, in particular during the milling operation of the ground milling machine, can be varied and adapted to operating conditions, be it with regard to a machine configuration and/or an effective variable and/or an operating variable of the ground milling machine, in particular as required.

The method according to the invention is intended in particular to be carried out with a ground milling machine according to the invention. The method steps disclosed for the ground milling machine according to the invention therefore represent, individually and in subcombinations, preferred embodiments of the method according to the invention. Reference is made at this point to the relevant disclosure in the context of the description of the ground milling machine according to the invention.

It is advantageous if the suction power is regulated by the control device as a function of at least one effective variable of the suction device and/or a dust emission, in particular from the milling drum box into the external environment, and/or a setting position and/or setting change or machine configuration and/or configuration change a machine element and/or an operating state of at least one machine element. Reference is made to the previous disclosure regarding possible effective variables, dust emissions, setting positions and/or setting changes or machine configurations and/or configuration changes of one or more machine elements and/or operating states.

For the method according to the invention, it is preferred if, using a sensor device, at least one effective variable of the suction device and/or a dust emission, in particular from the milling drum box into the external environment, a setting position and/or setting change or machine configuration and/or configuration change of a machine element and/or an operating state of at least one machine element and/or a measured variable correlating therewith is recorded and transmitted to the control device for controlling, in particular for regulating, the suction power available for the suction of air from the milling drum box. Reference is made to the previous disclosure regarding possible effective variables, dust emissions, setting positions and/or setting changes or machine configurations and/or configuration changes of one or more machine elements and/or operating states.

There are various options with regard to the specific regulation of the suction power available for the extraction of dust-containing air by the control device. It is, for example, advantageous if the suction power available for the suction of air from the milling drum box is controlled by changing the drive speed of one or more suction fans of the suction device from a first drive speed to at least a second drive speed and / or by changing the for Drive one or more suction fans of the suction device used drive power and / or by switching on or off a suction fan to another suction fan of the suction device and / or by changing the flow cross section in the suction channel of the suction device and / or by changing an opening area through which Air is sucked in through the suction device from outside the suction device, and/or by controlling/regulating a supply air device. Here too, reference is made to the previous disclosure for further details.

Figur 1:

eine Seitenansicht einer Bodenfräsmaschine in einem Arbeitszug mit einem Transportfahrzeug;

Figur 2:

eine vergrößerte Seitenansicht der Bodenfräsmaschine gemäß Figur 1;

Figur 3:

eine Absaugeinrichtung; und

Figur 4:

ein Ablaufdiagramm eines Verfahrens.

The invention is explained in more detail below using the exemplary embodiments shown in the figures. It shows schematically:

Figure 1:

a side view of a ground milling machine in a work train with a transport vehicle;

Figure 2:

an enlarged side view of the ground milling machine according to Figure 1 ;

Figure 3:

a suction device; and

Figure 4:

a flowchart of a procedure.

Identical or identically acting components are designated with the same reference numerals in the figures. Repetitive components are not designated separately in each figure.

Figure 1 shows a work train, comprising a ground milling machine 1, here a road milling machine, and a transport vehicle 2, specifically a truck. The ground milling machine 1 is enlarged again (except for part of the conveyor belt). Figure 2 shown.

The ground milling machine 1 has a machine frame 3, which forms the essential supporting structure of the machine. The ground milling machine can be operated from a driver's cab 4, which can, for example, be partially open and/or closed or designed as a driver's cab. The machine frame 3 is carried by front and rear driving devices 5 as seen in the working direction a. These can be designed as chain drives or as wheels. Some or all of the driving devices 5 can be driven. The driving devices 5 are mounted on the machine frame 3 via height-adjustable lifting devices 6, for example lifting columns. To provide the drive energy required for driving and milling operations, the ground milling machine 1 has a drive motor 7. This can be, for example, a diesel internal combustion engine or a comparable primary drive unit. The ground milling machine 1 has a milling device 8, the essential components of which are a milling tool, in the present case a milling drum 9, and a milling drum box 10. The milling drum box 10 surrounds the milling tool on the sides and upwards and thus shields the working area of the milling tool from the outside environment when it engages with the ground. The milling tool can be a milling drum 9, comprising a substantially hollow cylindrical support tube, on the outer surface of which a plurality of milling cutters and/or similar milling tools are arranged. During the milling operation of the ground milling machine 1, the milling drum engages in the ground subsoil at a milling depth FT and thereby mills off subsoil material while the machine advances in the working direction a. This is collected in the interior of the milling drum box 10 and passes through a suitable outlet opening onto a milled material conveyor 11 of the ground milling machine 1, with which the milled material is transported to a discharge point 14 is conveyed on the side of the ground milling machine 1 and is dropped from there, for example, into the transport vehicle 2 for the removal of the milled material. The milled material conveying device 11 can, as in the present exemplary embodiment, have two conveying units arranged in series, in this case an inner conveyor belt 12 and an outer conveyor belt 13, or even have only one conveying unit or even more than two conveying units. The ground milling machine thus includes its own milled material conveyor section for the milled material from the milling roller box 10 to the discharge point 14. This conveyor section of the milled material can be partially surrounded or shielded by housing elements and thereby have a substantially shaft- or channel-like structure and is therefore also referred to as Referred to as conveying channel. In particular for the inner conveyor belt 12, it is known to arrange this within a receiving shaft of the machine, so that parts of the machine frame and/or machine components surround a free space in which the inner conveyor belt and the milled material conveying path run. For the external conveyor belt 13, it is known to arrange wall elements on the support frame of the external conveyor belt in order to delimit the conveyor route from the outside. It is also possible that the milled material conveying device 11 is not, as in the present case, mounted with its discharge point directed towards the front of the ground milling machine 1 in the forward direction a, but in addition and/or alternatively to one side and/or towards the rear as seen in the working direction A is aligned. A transfer point can be provided between the inner conveyor belt 12 and the outer conveyor belt 13, at which the milled material is thrown from the inner conveyor belt 12 onto the outer conveyor belt 13 in the conveying direction. In the present exemplary embodiment, the milling device 8 is arranged in the working direction A between the front and rear driving devices 5. This type of ground milling machine is also known as a center rotor milling machine. So-called tail rotor milling machines are also known, in which the milling device is arranged between the two rear driving devices. The invention also extends to this type of ground milling machine.

Furthermore, so-called stabilizers and recyclers are known in the prior art as further types of ground milling machines. These can have a comparable structure. Stabilizers are used to mill up the subsoil and mix it with a binding agent. Recyclers mill up soil material and can also mix additives into the milled material. Stabilizers and recyclers include a milling device, but often no milled material conveying device, since the soil material processed by them regularly remains on the soil surface. The invention also extends to these machines in the manner described, but without the respective references to the milled material conveying device.

During the milling operation of the ground milling machine 1, a significant amount of dust can be generated. The main reason for this can be the milling work of the milling device 8 itself and/or the transport of the milled material along the milled material conveyor route. Accordingly, dust-contaminated air can escape into the outside environment, particularly in the area of the milling drum box 10 and/or in the area of the milled material conveyor 11, particularly in the area of the internal conveyor belt 12, and/or at the discharge point 14.

Ground milling machines 1 of the present type can have a sprinkler system 15 with which water, in particular in the form of a spray mist, can be applied to the interior of the milling drum box, an area of the milled material conveying path and/or in the area of the discharge point, among other things, to bind dust in dust-containing air. In the figures, the outlet nozzles of the sprinkler system 15 are shown only as examples. This also includes at least one water tank and/or a suitable line and/or valve system. The water released into the interior of the milling drum box can also be used to cool the milling tools. The dust reduction achieved with the water sprinkling device 15 is usually not sufficient.

In order to be able to reliably reduce dust emissions in the area of the milling drum box 10 and the milled material conveyor section, the ground milling machine 1 comprises a suction device 16. It can include a suction fan 17 or other suction device, via which the dust-contaminated air is removed from an area of the milled material conveyor through a suction channel 18 / or the milling drum box 10 can be vacuumed. Regardless of the specific exemplary embodiment, the suction fan can in particular be a radial fan. With the help of the suction fan 17, a volume of air can be conveyed and thus a negative pressure and ultimately a suction effect can be generated on a suction side of the suction fan 17. Via the suction channel 18, areas of the milled material conveying section and/or the milling roller box 10, especially its interior, can be integrated into this suction effect generated by the suction fan 17, in such a way that dust-containing air present and/or arising there is sucked out by the suction fan 17 towards the suction fan. The suction channel 18 thus designates the air guide path between the area of the milled material conveying path and/or the milling drum box, from which dust-containing air is sucked out to the suction fan. The suction channel can extend at least partially into the space of the milled material conveying section, as shown in Fig. 2 is shown in area I. The exemplary structure of a possible suction fan 17 and a suction channel 18 described so far is known in the prior art and, for example, in EP3225738B1 described. It is also already known that a region of the suction channel 18 runs along and/or through the milled material conveying path. In the present case, in particular a suction nozzle 20 can protrude into the receiving shaft of the internal conveyor belt 12 and downstream in a line, in particular a pipeline, separate from the milled material conveying section, up to the suction fan 17 run, as in Fig. 2 shown as an example. With this arrangement, a particularly good suction effect can be achieved in the area of the milled material conveying path practically immediately after the point at which the milled material is discharged from the milling roller box onto the milled material conveying device 11. This is also advantageous in that the suction effect generated by the suction fan can then extend particularly effectively into the milling drum box interior, so that dust-containing air can also be sucked out of the milling drum box interior. In addition or alternatively, regardless of the specific design of the milled material conveying section and the milled material conveying device, it can be provided to connect the described suction channel, which runs separately from the milled material conveying section, directly to the interior of the milling drum box 10.

In Figure 2 To further clarify the above information, the movement of the milled material along the milled material conveying section with the arrows M1, M2 and M3 as well as the movement of the extracted dust-containing air with the arrows D1, D2, D3, D4 and D5 up to the suction fan 17 (and in Fig. 3 additionally indicated with the arrows D6 and D7 downstream of the suction fan up to the outlet). The milled material emerges from the interior of the milling drum box 10 at arrow M1 and is overloaded onto the internal conveyor belt 12. This conveys the milled material along arrow M2 to the transfer point of the milled material to the external conveyor belt 13, from where it is transported along arrow M3 to the discharge point 14. According to arrow D1, dust-containing air is sucked out of the interior of the milling drum box 10 in the direction of the suction fan 17 via a common space in which the milled material is also transported according to arrow M1. The suction area also extends in particular over a part of the interior of the ground milling machine 1 in which the internal conveyor belt 12 runs, as illustrated by arrow D2. This room is in Figure 1 labeled I. The spatial separation of the extracted dust-containing air and the milled material takes place at the suction nozzle 20 (D3), from which, viewed downstream, the dust-containing air is spatially separated from the milled material up to the suction fan 17 according to the arrows D4 and D5. A further line section 21 can be provided downstream of the suction fan, via which the extracted air can be directed to a desired outlet point.

It can also be provided over the course of the line route that air that is sucked out and blown out is passed through a separating device 22, which is designed to separate dust particles contained in the dust-containing air from the air flow. An example of this is in Figure 2 An electric separator is present as a separating device 22, through which the extracted dust-containing air is passed, in this case only as an example downstream of the suction fan 17. The positioning of the separator 22 in Reference to the line route of extracted and blown air as well as their structural design can vary. For example, cyclone filters, fabric filters and similar separation devices 22 can also be used here. An arrangement upstream of the suction fan is also possible.

It is essential for the design of the ground milling machine 1 according to the invention that the suction device 16 includes a control device 19. The task and function of the control device 19 is to regulate the suction power of the suction device 16, in particular the suction fan 17, available for the suction of air from the milling roller box and/or the area of the conveying channel of the milled material. The control device 19 thus makes it possible to change the suction power available for the extraction of dust-containing air from the milling drum box and/or the area of the conveying channel of the milled material and thus to react, for example, to changing operating conditions of the ground milling machine 1. By simply switching the suction device on and off or activating and deactivating it, it is at least possible according to the invention to change the activated state of the suction device, i.e. a state in which dust-containing air is extracted, between at least two operating stages, which differ with regard to the suction distinguish the suction power available for dust-containing air, and/or within a possible operating range within which the suction power available for the suction of dust-containing air can be changed and/or the operating state of the suction device, in particular the drive and/or fan speed of the suction fan. In this way, in particular, the air containing dust for extraction from the relevant areas of the ground milling machine 1 described above can be adapted to the current needs or to operating situations with increased or less dust development. With regard to further developments according to the invention, reference is also made explicitly to the variation options disclosed above before the description of the figures, which are not necessarily explicitly shown in every detail in the figures.

The control device 19 preferably controls a device of the suction device 16, with the help of which the suction power available for the suction of dust-containing air can be varied. This can be done, for example, by controlling a fan drive device 23, for example an electric and/or hydraulic motor. In Figure 2 For this purpose, a control line 24 is provided, which connects the control device 19 to the fan drive device 23. Additionally or alternatively, a controllable supply air device 25 can also be present upstream of the suction fan 17. The supply air device 25 can be a device with a supply air opening, via which additional, in particular Non-dust-containing air from the outside environment of the ground milling machine 1 can also be sucked in. The opening cross section of the supply air opening can be variable in order to be able to vary the extent of the additional ambient air flowing in. For this purpose, controllable, driven flap and/or lamella elements or something similar can be provided. Of the suction power generated by the suction fan 17, a variable proportion can then be allocated to the suction of non-dust-containing air using the supply air device 25, so that overall less suction power is available for the suction of dust-containing air and vice versa. The supply air device 25 can also be in signal connection with the control device 19 via a control line. As a precautionary measure, it should also be noted that the design of the control lines and/or signal lines mentioned in the context of the invention is obviously variable with regard to the specific embodiment and, for example, wired and/or wireless signal and/or control lines can be used for this purpose. Additionally or alternatively, for example, the blade angle position of the fan blades can also be changed and adjusted by the control device 19 to change the suction power of the suction device 16. It goes without saying that in this case the fan wheel has correspondingly adjustable guide blades.

In order to be able to adapt the suction power available for the suction of dust-containing air to different conditions, the suction device 16 can comprise a sensor device 26. This can be varied in many ways and is particularly relevant in connection with the Figure 3 explained in more detail. In the exemplary embodiment according to Figures 1 and 2 Part of the sensor device 26 can be a camera 27, which is arranged on the ground milling machine 1 in such a way that it records an area in its recording area, in particular between the lower edge of the milling drum box 10 and the floor covering B, in which dust-containing air from the interior of the Milling drum box 10 can exit to the outside environment. From the image information obtained, it can now be determined using suitable image processing software whether the image or images recorded show a cloud of dust or not, for example via image comparisons, 3D image analysis and/or the like. Additionally or alternatively, a pressure sensor 28 is arranged on and/or in the milling drum box, with the help of which it can be determined whether and/or how high a negative pressure is inside the milling drum box 10. If there is a negative pressure there, this is an indicator that dust-containing air is being sucked out of the milling drum box interior in the direction of the suction fan 17. This means that suction power is available at the milling drum box. The sensor 28 can also be a flow direction sensor or similar, with which it can be determined whether air is sucked in from the outside environment into the interior of the milling drum box via this sensor due to a negative pressure maintained inside the milling drum box 10. It goes without saying that the corresponding sensors are also in signal connection with the control device 19.

Figure 3 illustrates the interaction of the control device 19 with further elements of the suction device 16. The control device 19, which, regardless of the specific exemplary embodiment, can in particular be a control device, can, for example, control the fan drive device 23 via the control line 24. Furthermore, a feedback line 29 can be provided, via which the control device 19 can receive actual operating data for the operation of the fan drive device 23, for example a current fan speed. Furthermore, a control line 30 can connect the control device 19 to the supply air device 25. This can, for example, have a driven slide and a supply air opening which is variably covered by this and is in flow connection with the suction channel 18. The supply air device 25 can also report information about its current actual state to the control device 19. The control commands transmitted from the control device 19 to the blower drive device 23 and/or supply air device 25 in the present exemplary embodiment can be based on operating data obtained via the sensor device 26.

For this purpose, the sensor device 26 can have one or more sensors that record actual operating data relevant to the current dust development of the ground milling machine 1. For this purpose, the sensor arrangement 26 can be designed, for example, to detect an effective variable of the suction device 16. Examples of sensors for this are in block 26.1 in Figure 3 stated. For example, the pressure sensor 28 can be present for this purpose, with which an existing air pressure within the milling drum box and/or within an area of the suction channel 18, in particular between the milling drum box 10 and the suction fan 17, can be detected. Additionally or alternatively, an air pressure difference sensor 30 can also be present, which is used to determine an air pressure difference within the milling drum box 10 and/or within an area of the suction channel, in particular between the milling drum box and the suction fan, and an air pressure outside the milling drum box 10 and outside the suction device, in particular an ambient air pressure of the ground milling machine 1 is formed. The air pressure difference sensor 30 can, for example, include two air pressure sensors arranged at a suitable location to determine the existing air pressure difference (inside vs. outside). Additionally or alternatively, a flow direction sensor 31 and/or a volume flow sensor 32 can also be parts of the sensor device 26, with the help of which the existence of a directed air flow and/or the extent of an existing air flow can be determined. For this purpose, the sensors 31 and/or 32 can be integrated into a corresponding throughput measuring opening in one of the wall elements of the milling drum box 10 and/or the suction channel 18. If there is a negative pressure in one or both of these areas, air is sucked in from outside through the corresponding through-measuring opening on the and/or through the sensors 31 and/or 32 into the interior of the milling drum box and/or the suction channel 18. Further supplementary or alternative A flow velocity sensor, not shown in detail, can also be present, with which the flow velocity of the extracted dust-containing air and/or the air blown out downstream of the suction fan is determined. In particular, such a flow velocity sensor can be used in combination with a separation device, in particular an electric separator and/or a cyclone separator, whereby the flow velocity sensor can be positioned before, in or after the separation device as viewed in the flow direction of the respective separation device. For an electric separator, for example, it may make sense that a maximum flow rate is not exceeded in order to prevent material that has already been deposited from being carried away by the air flow again. For a cyclone separator, however, it can make sense that the flow speed does not fall below a minimum in order to ensure a sufficiently effective separation effect. It is also possible to define a flow velocity range within which the flow velocity of the extracted dust-containing air should lie (obviously always based on the specific measuring point). This can be defined by the maximum and minimum flow speed described above, particularly when using a cyclone separator and an electrical separator in combination, both arranged in series with one another.

Additionally or alternatively, the sensor device 26 can comprise a sensor which is connected to an actual dust development and/or an actual dust exit, in particular from the interior of the milling drum box 10, to the outside environment and/or from the conveyor section or the milled material conveyor device 11 to the outside environment , correlating measured value is determined and transmitted to the control device 19. Examples of suitable sensors for this are in subgroup 26.2 of the sensor device 26 in Figure 3 stated. In addition to the camera 27 and suitable image processing software, a dust sensor or dust detector 33 can also be used as a supplement or alternative. Such a dust sensor can, for example, make a qualitative and/or quantitative statement about a current dust load in the air supplied to the dust sensor based on a photometric measuring principle (extension or scattering). The dust sensor 33 is expediently arranged on the ground milling machine 1 in an area in which dust emerging from the milling drum box interior and/or the milled material conveying path will be present during the milling operation of the ground milling machine 1. This can in particular be the external surrounding area of the milling drum box 10, the external surrounding area around and/or along the elements of the ground milling machine 1 housing the milled material conveying path. Particularly with regard to undesirable dust exposure of the operator of the ground milling machine 1, such a dust sensor 33 can also be arranged in the area of the control station 4. Since the places where dust can potentially get into the areas mentioned here External environment can escape, also depending on the wind, it makes sense to arrange and monitor such sensors at several potentially relevant locations on the ground milling machine 1 at the same time. Regardless of this, as a precautionary measure, it is additionally noted that the dust escape from the milling drum box and/or the milled material conveyor does not necessarily have to be towards the outside environment and must serve as a measure of dust escape. Of course, there can also be areas within the ground milling machine 1, for example in the receiving shaft of the internal conveyor belt, in which dust can (also) escape. Of course, dust emissions can also be determined at these points in the manner described above.

Additionally or alternatively, the sensor device 26 can also include one or more sensors with which the operating state of at least one machine element can be determined. This sensor group is in block 26.3 in Figure 3 stated. In particular, the sensor device 26 can have a position sensor 34, which is designed to determine the position and/or a change in position of a machine element of the ground milling machine 1 relative to another element. This can be, for example, the lifting position of a lifting device connecting a driving device to the machine frame, the lifting and / or pivoting position of a side shield relative to the rest of the milling drum box and / or the machine frame, the lifting position of a scraper shield, the pivoting position of a part of the milled material conveyor 11, or similar. These adjustable elements can influence, for example, the tightness of the milling drum box 10 and/or the suction channel 18 and can therefore be an indicator of when, for example, the speed of the suction fan 17 can be increased or decreased in order to avoid dust escaping to the outside. In particular in this case, the control device 19 can also include one or more characteristic maps which combine various control and/or control specifications controlled by the control unit 19 for certain configurations of the ground milling machine 1.

The category 26.3 of sensors of the sensor device 26 additionally or alternatively also includes sensors with which the operating state of elements of the ground milling machine, in particular with regard to activation and / or activation, can be determined and transferred to the control device 19. Such operating status sensors are in Figure 3 indicated above with the reference number 35. Such operating state sensors can, for example, be designed to detect the operating state of the milling drum 9, the sprinkler system 15, the milled material conveying device 11, the separating device 22 or similar in the manner described above and transmit it to the control device 19.

For all of the sensor measured values described above, these can be direct measured values of the determined quantity and/or values that correlate with it.

Figure 4 illustrates possible embodiments of a method according to the invention, in particular for a ground milling machine 1 with a control device 19, as in the Figures 1 , 2 and 3 described as an example.

The focus of the method according to the invention is the control, in particular rules 36, of the suction power used to extract air from the milling drum box using a control device, in particular the control device 19. For this purpose, it can be provided that the control, in particular rules 36, is a Transmitting 37 control commands to a device for changing the suction power available for extracting air from the milling drum box. This device can in particular be a fan drive device, such as a hydraulically and/or electrically driven fan wheel motor, and/or a supply air device. With the help of the transmitted control command, the current operating state of the suction device can be changed in step 38 with regard to the suction power available for the suction of air from the milling drum box. It goes without saying that this can be done unidirectionally or bidirectionally, in which case the new actual value of the respective operating state of the suction device that has occurred due to the change is reported back to the control device.

In particular, the regulation 36 can take place depending on different sizes. For example, a transmission 39 of an effective variable of the suction device can be provided. This can be a pressure measurement, for example. For this and other alternatives, reference is made to the above statements. Additionally or alternatively, a transmission 40 of a current dust emission can also be provided, with reference being made to the previous statements for further details. Additionally or alternatively, there is also the possibility that a transmission 41 of a setting position and/or setting position change of a machine element and/or an operating state of at least one machine element is provided, depending on which the regulation 36 of the suction power can take place. Here too, reference is made to the previous statements for further details.

The actual variables shown in steps 39, 40 and 41 can be recorded during ongoing milling operation using suitable sensors in steps 42, 43 and 44. Which sensors and which measuring locations can preferably be considered have already been described above, so that reference is made here in addition to the previous relevant statements.

The steps described above can occur continuously during the milling operation. Effects of changing 38 can be done in particular via steps 42 and 43 is recorded and for which Rules 36 are further taken into account. This is in Figure 4 stated as 45.

In principle, it is possible to design the method according to the invention with regard to the suction power available for extracting dust-containing air in such a way that at least two power levels, for example at least two different speeds of a suction fan, can be set depending on the variables described above. A substantially stepless change, in particular a speed of a suction fan, within a speed range is also possible. At the same time, however, it is optimal if the suction power available for extracting dust-containing air is not permanently too high. If the suction power available for extracting dust-like air is chosen to be too high, this is disadvantageous from an energy and ecological point of view. On the other hand, this can, for example, negatively influence the separation performance of one or more separation devices that may be present. For example, if the suction power is selected too high and the associated comparatively high flow velocities within the suction channel, the separation rate of an electric separator can be negatively influenced. The regulation 36 is therefore preferably carried out in such a way that the suction device is operated at the lowest possible suction power available for the suction of dust-containing air. With the help of the arrangement described above, this can be done, for example, in such a way that only a comparatively low negative pressure and/or a comparatively small inflow of air into the milling drum box or the like are sought. Specific, sensible limit values regularly depend on the actual structural conditions.

In this context, however, it is particularly efficient with regard to the operation of the suction device and at the same time with regard to dust extraction if a possible dust escape from the milling drum box and / or an area of the milled material conveyor is observed, in particular as already described above, and the suction power is regulated in such a way, that no dust or at least only a very small amount of dust is escaping. The regulation 36 is therefore preferably carried out in the sense of a limit load control, the limit load here being the prevention of dust escaping from the milling drum box and/or an area of the milled material conveying device, in particular into the external environment. The control device 19 can therefore in particular also be designed as a limit load control device, regardless of the above, merely exemplary information about the method according to the invention.

Claims (14)

Soil milling machine (1), in particular road milling machine, recycler or stabilizer, for processing a soil in or against a working direction (a), comprising - a machine frame (3) carried by driving devices (5) with a drive motor (7), - A milling drum (9) rotatably mounted in a milling drum box (10) arranged on the machine frame (3) for removing soil material and - a suction device (16) for extracting dust-containing air from the milling drum box (10) and/or an area of a conveying channel of the milled material, comprising a suction fan (17) and at least one suction channel (18) running from the milling drum box (10) to the suction fan (17). ), characterized,
in that the suction device (16) comprises a control device and is designed such that, with the help of the control device (19), the suction power of the suction device (19) available for the suction of dust-containing air from the milling drum box (10) and/or the area of the conveying channel of the milled material ( 16) can be changed. Ground milling machine (1) according to claim 1,
characterized,
that the control device (19) is designed such that it controls the suction power available for the suction of air from the milling drum box (10) depending on - an effective variable of the suction device (16) and/or - a dust emission and/or - a setting position and/or setting change and/or an operating state of a machine element, especially during a milling process. Ground milling machine (1) according to one of the preceding claims,
characterized ,
in that the suction device (16) comprises a sensor device which is designed in such a way that it determines the current value and/or a measured variable correlating therewith of an effective variable of the suction device (16) and/or a dust emission, which is in particular representative of - the extraction of air from the milling drum box (10) and/or - Dust escapes from the milling drum box (10) to the outside environment. Ground milling machine (1) according to one of the preceding claims,
characterized,
in that the suction device (16) comprises a sensor device (26), which is designed such that an effective variable of the suction device (16) determined by it is at least one of the following effective variables and / or a measured variable that correlates with the respective effective variable: - Air pressure within the milling drum box (10) and/or within an area of a suction channel (18), in particular between the milling drum box (10) and the suction fan; - Air pressure difference between an air pressure inside the milling drum box (10) and/or within an area of a suction channel, in particular between the milling drum box (10) and the suction fan, and an air pressure outside the milling drum box (10) and outside the suction device (16), in particular one Ambient air pressure of the ground milling machine (1); - Direction of air flow into the interior of the milling drum box (10); - Volume flow of air flowing into the interior of the milling drum box (10). Ground milling machine (1) according to one of the preceding claims,
characterized,
that the suction device (16) comprises a sensor device (26) which has at least one of the following sensors: - air pressure sensor; - air pressure difference sensor; - dynamic pressure sensor; - volume flow sensor; - flow direction meter; - camera; - Dust detector. Ground milling machine (1) according to one of the preceding claims,
characterized,
in that the suction device (16) comprises a sensor device (26) which is designed such that it determines the current value and/or a measured variable of a setting position and/or setting change and/or an operating state of at least one machine element, and that the Control device (19) regulates the suction power available for the suction of air from the milling drum box (10) depending on at least this determined setting position and / or setting change and / or this determined operating state. Ground milling machine (1) according to one of the preceding claims,
characterized,
in that the suction device (16) comprises a sensor device (26) which is designed to determine the setting position and/or the setting change of the at least one machine element and has at least one of the following features: - It is designed to determine the stroke position and/or change in stroke position of a scraper shield of the milling drum box (10), in particular relative to the machine frame; - It is designed to determine the lifting and/or pivoting position and/or lifting and/or pivoting position change of at least one side plate of the milling drum box (10), in particular relative to the machine frame; - It is designed to determine the actual milling width of a milling drum (9). Ground milling machine (1) according to one of the preceding claims,
characterized,
in that the suction device (16) comprises a sensor device (26) which has at least one of the following features to determine the operating state of the at least one machine element: - A device for determining whether a milling drum (9) of the ground milling machine (1) is driven and/or rotates about its axis of rotation and/or at what speed the milling drum rotates about its axis of rotation; - a device for determining whether the milling drum is in milling operation; - a device for determining a milling depth; - a device for determining whether a water sprinkler system, which dispenses water into the interior of the milling drum box (10) and/or in the conveying area of the milled material within the ground milling machine (1) and/or in the area of a material discharge point, is activated or deactivated; - a device for determining whether a particle filter device, in particular an electrical separator, is present and/or activated; and that the control device (19) regulates the suction power available for extracting air from the milling drum box (10) depending on at least one of these operating states. Ground milling machine (1) according to one of the preceding claims,
characterized,
in that the dust extraction device (16) has at least one of the following features to change the suction power available for extracting air from the milling drum box (10): - The suction fan comprises a fan drive motor, in particular a hydraulic or electric motor, which is continuously adjustable in terms of its drive speed, in particular within a speed range; - the fan drive motor, in particular a hydraulic or electric motor, is driven in such a way that the drive power supplied to the suction fan is varied by the control device (19), - It comprises a plurality of fan drive motors, each of which drives at least one fan wheel; - It comprises an, in particular controllable, air inflow device, in particular comprising a supply air flap/slide that is variable with regard to its opening area. Ground milling machine (1) according to one of the preceding claims,
characterized,
that the control device (19) is designed in such a way that it uses the suction power available for the suction of air from the milling drum box (10). - regulates a limit value that cannot be exceeded or fallen below; - regulates continuously within a limit value range; or - In addition to a deactivated state of the suction device (16), it regulates between at least two suction powers generated by the suction device (16). Method for operating a dust extraction device (16) of a ground milling machine (1) (1), in particular a ground milling machine (1) according to one of the preceding claims,
characterized,
that the suction power available for extracting air from the milling drum box (10), in particular in a controlled manner, can be changed using a control device (19). Method according to claim 11,
characterized,
that the suction power is regulated depending on at least - an effective variable of the suction device (16) and/or - a dust emission and/or - a setting position and/or setting change of a machine element and/or - an operating state of at least one machine element. Method according to one of claims 11 or 12,
characterized,
that using a sensor device (26) at least - an effective variable of the suction device (16) and/or - a dust emission and/or - a setting position and/or setting change of a machine element and/or - an operating state of at least one machine element and/or a measurement variable correlating therewith is recorded and transmitted to the control device (19) for regulating the suction power available for the suction of air from the milling drum box (10). Method according to one of claims 11 to 13,
characterized,
that the suction power available for extracting air from the milling drum box (10) is regulated - by changing the drive speed of one or more suction fans of the suction device (16) from a first drive speed to at least a second drive speed; and or - by changing the drive power used to drive one or more suction fans of the suction device (16); and or - by switching a suction fan on or off to another suction fan of the suction device (16); - by changing the flow cross section in a suction channel of the suction device (16); - and/or by changing an opening area through which air is sucked in by the suction device (16) from outside the suction device (16).

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