SHELL-JOINTED TANDEM ROLLER AND METHOD FOR OPERATING SUCH ROLLERS

Description

[0001] The invention relates to a pivot-steered tandem roller for soil compaction and a method for operating such a tandem roller.

[0002] Tandem rollers of this type are used for subsoil compaction, particularly in road and path construction, as well as in the construction of airports and runways. They are typically used for compacting asphalt. Tandem rollers typically comprise a machine frame with an operator's cab, which has a cabin to protect the roller driver and corresponding controls. In addition, tandem rollers of this type typically comprise two compactor rollers that are spaced apart from one another in the longitudinal direction of the machine and are commonly referred to as drums. The compactor rollers are in particular cylindrical steel drums that have, for example, smooth or textured outer surfaces. Typically, one compactor roller is arranged at the front when viewed in a forward direction and one at the rear when viewed in this forward direction. The operator's cab is usually located in between.One or more compactor rollers can also be split. In this case, a compactor roller refers to a unit rotating around a common axis of rotation. The compactor rollers are each mounted on the machine frame so they can rotate and be steered via a pivot steering system. In this case, pivot steering means that the compactor rollers are designed to be rotatable about a vertical steering axis via a pivot, which extends through the compactor roller and, in particular, intersects the axis of rotation of the compactor roller, around which the compactor roller rotates for rolling on the outer surface while the tandem roller is traveling. Such a tandem roller with two pivot-steered compactor rollers is known from DE 296 20 847 U1, owned by the applicant.To enhance the compaction effect, it may additionally be provided to cause one or both of the compactor rollers to vibrate during operation via an unbalance exciter, for example a vibration or oscillation exciter. Furthermore, it is known to wet the compactor rollers with a liquid, such as water, during operation in order to reduce or prevent soil material from adhering to the compactor rollers. Tandem rollers of this type therefore usually also have at least one liquid tank to keep the appropriate liquids, especially water, in stock during operation. A drive motor, such as a diesel combustion engine, is typically used to supply these tandem rollers with power.To counteract the heat generated during operation of the tandem roller and / or to increase operational efficiency, these rollers typically also have a cooler, such as a hydraulic fluid cooler, a coolant cooler, and / or a charge air cooler. This cooler is associated with a fan that promotes a flow of cooling air through the cooler, thereby cooling the medium contained in the cooler.

[0003] In conventional pivot-jointed tandem rollers, the radiator and the associated fan are typically located in the engine compartment below the operator's cab, where the drive motor is also located, or at least in the immediate vicinity of the engine compartment. Ever-stricter emissions regulations have resulted in changes to engines and exhaust aftertreatment components over the years. For example, increasingly larger and / or an ever-increasing number of components, such as SCR systems, must be installed in the machines, as diesel combustion engines of sufficient power today largely require exhaust aftertreatment to reduce nitrogen oxide emissions. Likewise, the requirements for cooling performance have increased accordingly, necessitating larger radiators and / or a more efficient cooling concept.The often already very limited space available in the engine compartment of a tandem roller of this type requires compensating for space gains by reducing or downsizing other components. For example, the volume of the water tanks used to moisten the compactor rollers is often reduced. However, this naturally means that the water tanks have to be refilled more frequently during roller operation, which leads to delays in the workflow and higher costs. If, however, the coolers are not designed large enough due to a lack of space, the operating efficiency of the entire machine decreases. Rollers with cooling systems are known, for example, from DE 26 34 672 A1 and JP 2019 039 255 A.

[0004] The object of the present invention is to optimize the operation of a generic tandem roller and, in particular, to enable particularly effective cooling air management.

[0005] The problem is solved with a tandem roller and a method according to the independent claims. Preferred developments are specified in the dependent claims.

[0006] Specifically, the solution for a pivot-steered tandem roller of the type mentioned above is achieved by arranging the cooler vertically above and / or in the longitudinal direction of the machine at the level of one of the compactor rollers. It is particularly preferred for the cooler to be arranged both vertically above and in the longitudinal direction of the machine at the level of one of the compactor rollers. In these, albeit spatially restricted, areas of the tandem roller, which, among other things, usually contain the steering joints of the pivot steering, the available space can be used to accommodate at least one cooler. Although this is spatially separated from the drive motor, which is usually located below the driver's cab, this can be accepted in view of the advantages gained.The core of the invention is that the radiator is relocated from the engine compartment, which is typically located in the center of the machine under the operator's cab, to another machine compartment assigned to one of the compactor drums. The radiator is therefore located outside the engine compartment. This frees up space on one side of the engine compartment, which can be used for additional components, such as an exhaust aftertreatment system (e.g., SCR). "selective catalytic reduction")can be used. On the other hand, the cooler, which also requires space, is relocated to an area of ​​the tandem roller where it can be dimensioned to the necessary size without having to significantly restrict the size and associated efficiency of other machine components. This type of cooler arrangement has been avoided to date because it can, in particular, require a comparatively long and complex cooling air duct extending through large parts of the machine. This is particularly true if effects of the cooling air management on the outside environment, for example due to dust turbulence, etc., are to be avoided. As will be explained in more detail below, in preferred embodiments of the invention it has even been realized that further advantages can be gained from the cooling air duct itself.

[0007] In this case, the vertical direction is understood to be a direction perpendicular to a flat, horizontal ground on which the tandem roller stands. The longitudinal direction of the machine is the horizontal direction, which is usually referred to as the forward or reverse direction, particularly during normal operation of the tandem roller when traveling straight ahead. In this case, the rotation axes of the compactor rollers run in the horizontal plane perpendicular to the longitudinal axis of the machine. In particular, the longitudinal direction of the machine runs parallel to a flat ground on which the tandem roller stands. If the tandem roller is operated in crab steering, the longitudinal direction of the machine runs obliquely to the forward direction. The fact that the cooler is located vertically above one of the compactor rollers means that a projection of the contours of the compactor roller and the cooler in the vertical direction at least partially overlap.The fact that the cooler is arranged at the level of one of the compactor rollers in the machine longitudinal direction means that the contours of the compactor roller and the cooler at least partially overlap in a projection transverse to the machine longitudinal direction.

[0008] With the pivot steering system, the compactor rollers are steered via a turntable mounted on the machine frame. The turntable is therefore positioned vertically above the compactor roller and centrally at the rear or front of the machine, or at the first or second steering section, as explained in more detail below. The present invention allows for the creation of space above the turntable for accommodating the cooler, which is why it is preferred that the cooler be arranged vertically not only above a turntable but also above a turntable of the pivot steering system of one of the compactor rollers.

[0009] In principle, the cooler can be designed to cool any operating medium of the tandem roller. For example, the cooler can be designed as a hydraulic fluid cooler, a cooling fluid cooler, or a charge air cooler. However, it is preferred if the cooler cools several operating media of the tandem roller simultaneously (combination cooler) or is part of a cooler package consisting of several individual coolers. In other words, it is preferred that the cooler is designed as a cooler package and comprises at least two, in particular all three, of the following coolers: a hydraulic fluid cooler, a cooling fluid cooler, and / or a charge air cooler. Since not all modern diesel engines require a charge air cooler, it is particularly preferred that the cooler designed as a cooler package comprises, for example, a hydraulic fluid cooler and a cooling fluid cooler.

[0010] In order to enhance the cooling effect of the cooler, a fan is assigned to the cooler which promotes a flow of cooling air, whereby this flow of cooling air is passed through the cooler. The fan is therefore designed, for example, as an air-conveying fan. Overall, the fan assigned to the cooler supplies cooling air to the cooler. They are therefore functionally related to one another. This means that it can be preferable if the cooler and the fan are arranged in spatial proximity to one another. For example, it can therefore be provided that the fan assigned to the cooler, analogous to the cooler, is arranged vertically above and / or in the longitudinal direction of the machine at the level of one of the compactor rollers, i.e. in the same machine compartment. In this embodiment, the fan is therefore still in the immediate spatial proximity to the cooler. In particular, the fan is located in the same compartment of the machine or in the same machine room.This results in a particularly short flow path between the fan and the radiator, which contributes to efficient cooling. Alternatively, the fan can be arranged on a power take-off of the drive engine. In this embodiment, the fan is therefore arranged in close proximity to the drive engine, for example still in the engine compartment. In this case, the fan and the radiator are therefore essentially spatially separated from one another, since the radiator is located outside the engine compartment. In this way, both the installation space in the engine compartment and the installation space outside the engine compartment can be optimally used to accommodate the cooling components. The fan can be arranged behind the radiator in the direction of cooling air flow so that it draws cooling air through the radiator. Alternatively, the fan can be arranged in front of the radiator in the direction of cooling air flow so that it blows cooling air through the radiator.Depending on the space required by other components in the immediate vicinity of the fan and cooler, one or the other approach can optimize installation space consumption. The fan can generally be driven in a variety of ways. For example, the fan can be assigned a separate, dedicated fan drive, such as a hydraulic or electric fan drive. Using a separate fan drive allows the fan to be positioned particularly flexibly. Alternatively, it can also be driven by a power take-off of the drive motor, particularly via a belt drive, particularly if the fan is located in the area of ​​the power take-off of the drive motor. Driving the fan directly via a power take-off of the drive motor is often particularly energy-efficient.

[0011] Pivot-steered tandem rollers are, in terms of their machine and functional areas, constructed almost symmetrically in the longitudinal direction of the machine. In particular, three parts can be distinguished: a first, front steering part with the first compactor roller, a second, rear steering part with the second compactor roller, and a drive and operating part between the two steering parts. The drive and operating part typically comprises the driver's cab and the engine compartment located beneath the driver's cab with the drive motor. However, the steering parts also comprise enclosed machine compartments in which components of the tandem roller can be housed. Thus, the invention provides that, in the longitudinal direction of the machine, both in front of and behind the driver's cab, a drive and operating part that is at least partially enclosed or covered is arranged.a substantially enclosed machine room is present, which in particular belongs to the respective steering part and is located in particular vertically above one of the compactor rollers. The cover can, for example, comprise a hood, for example made of plastic, which can, for example, be designed to be pivotable in order to provide access to the respective machine room. The cover delimits the machine room, for example vertically upwards and / or transversely to and / or in the longitudinal direction of the machine. It is, for example, possible for the cover to represent part of the outer skin or outer contour of the tandem roller. Both steering parts can each have such a cover and a machine room at least partially enclosed by the cover.The covers can, for example, be designed such that they slope away from the driver's cab and downwards in a vertical direction to allow the driver a better view of the ground in front of or behind the tandem roller from the driver's cab. According to the invention, the front cover and the rear cover have ventilation openings on their vertically upper side for the cooling air flow conveyed by the fan. The ventilation openings can, for example, be designed or used to allow cooling air from the outside of the tandem roller to enter the machine room or to allow cooling air from the machine room to exit into the outside of the tandem roller.It is particularly preferred that both the front and rear covers each have such ventilation openings, with the ventilation openings of one cover being designed for the inlet and the ventilation openings of the other cover being designed for the outlet of the cooling air. By arranging the ventilation openings on the vertically upper side of the cover, the intake air is drawn in relatively far from the floor, so that less dust is sucked into the machine with the cooling air. By blowing the cooling air out on the vertically upper side of the cover, it is ensured that the exhausted air does not stir up dust.

[0012] The cooler according to the invention is accommodated in particular in one of the machine rooms above or above the steering parts or the turntables. For example, the cooler can be arranged in the front machine room or in the rear machine room. In a preferred embodiment, the fan assigned to the cooler is also accommodated in one of the machine rooms above the steering parts or a turntable, for example in the front machine room or in the rear machine room. The cooler and fan can be accommodated in different machine rooms. For this arrangement, it is preferred, in particular, to position the fan in the front machine room above the front compactor roller and the at least one cooler in the rear machine room above the rear compactor roller. It is particularly preferred if the cooler and the fan assigned to the cooler are both in the same, in particular the rear, machine room, iein the engine room above the rear compactor roller.

[0013] In particular, when the cooler and the fan are not arranged in the same machine room, but in different machine rooms, a flow duct is provided which connects the two machine rooms of the steering parts, i.e. the front and rear machine rooms, through the engine room in the drive and operating section of the tandem roller. However, such a flow duct can also be provided if the fan and cooler are arranged in the same machine room. According to the invention, it is either provided that a flow duct is present which is designed such that the cooling air flow conveyed by the fan is conveyed from the outside environment of the tandem roller into the front machine room. From there, the cooling air flow is then conveyed vertically downwards and to the rear into the engine compartment arranged below the driver's cab.The cooling air flow is then guided essentially horizontally through the engine compartment and from there conveyed vertically upwards and backwards into the rear machine compartment. From the rear machine compartment, the cooling air flow is then blown out again into the outside environment of the tandem roller. This type of cooling air flow, in combination with the inventive positioning of the cooler as described above, enables particularly efficient cooling air flow, improves the cooling efficiency compared to conventional systems and thus permits, among other things, comparatively environmentally friendly operation. In principle, however, the conveying direction can also be reversed according to the invention, so that the cooling air flow is conveyed from the outside environment via the rear machine compartment, the engine compartment, then the front machine compartment and back into the outside environment. At one point in the flow channel, the cooling air flow flows through the cooler.

[0014] Preferably, the cooling air flow flows through the cooler in an at least partially upward direction, particularly in an ascending and obliquely rearward direction relative to the machine's longitudinal direction. The cooler, which is generally designed as a substantially cuboid-shaped body with two opposing, substantially flat flow surfaces (cooling air inlet and cooling air outlet), is thus preferably positioned in an inclined position. "Inclined position" refers to an arrangement in which the planes of the flow surfaces extend at an angle to a vertical or intersect it. The inclined position for the cooler is particularly selected such that the cooler rises in the machine's longitudinal direction toward the driver's cab and falls away from the driver's cab.The area of ​​the radiator further away from the driver's cab is therefore lower in the vertical direction than the area of ​​the radiator oriented towards the driver's cab.

[0015] It is now preferable to select the inclined position of the cooler such that the flow direction through the cooler with the cooling air flow conveyed by the fan deviates less from the vertical direction than from the horizontal direction. For example, the flow direction should deviate from the vertical direction by a maximum of 40°, preferably a maximum of 30°, more preferably a maximum of 20°, and particularly preferably a maximum of 10°. This allows the plane of the main extension of the cooler to approach the horizontal in a corresponding manner. This allows the cooler to be arranged in a particularly space-saving manner under the cover of the machine rooms of the steering parts of the tandem roller, while at the same time enabling optimized visibility. The preferred upward flow direction also leads to further advantages, which are described in more detail below.

[0016] As already mentioned at the beginning, tandem rollers of this type typically have liquid tanks, in particular water tanks, which are used to wet the compactor rollers and prevent the material to be compacted from sticking. In order to ensure the lowest possible center of gravity of the machine despite the additional weight of the liquid tanks, the liquid tanks are preferably arranged in the area of ​​the engine compartment or at least below the driver's cab on the drive and control section of the tandem roller. At the same time, accessibility to the engine compartment for maintenance work must be guaranteed. Therefore, according to a preferred embodiment, it is particularly advantageous if the engine compartment is delimited on both sides transversely to the longitudinal direction of the machine by an engine compartment door, wherein the engine compartment doors each have a liquid tank, preferably for storing water for the sprinkler system.The fluid tank is designed to be pivotable with or mounted on the respective engine compartment door. The fluid tanks are therefore located opposite each other on the respective machine sides, transverse to the longitudinal direction of the machine. In particular, it is now provided that the cooling air flow conveyed by the fan is conveyed between the two fluid tanks, with the radiator being located outside the area between the two fluid tanks. The flow channel through the engine compartment requires significantly less space as long as the radiator is not also located in the engine compartment. In this way, the fluid tanks can be equipped with sufficient volume for long working times without filling. At the same time, the cooling performance of the radiator is not affected, as it is located in a different machine compartment, outside the engine compartment.The invention leads to an advantageous use of the installation space, particularly in the case where one, several or in particular all of the liquid tanks of the tandem roller are arranged in the drive and operating part, for example in the engine compartment, and the cooler is arranged in one of the steering parts, for example in one of the machine compartments.

[0017] In principle, it is sufficient if the cooling air is sucked in through the ventilation openings on one of the covers. However, the cooling air passed through the tandem roller is not only heated in the radiator, but also, for example, by the drive motor in the engine compartment. It can therefore be advantageous to introduce fresh cooling air into the flow duct, for example behind the engine compartment or downstream of the engine compartment as seen in the direction of flow of the cooling air. For this purpose, a preferred embodiment provides for an intake duct, in particular an additional intake duct, to be arranged between the driver's cab and the ventilation openings through which the cooling air flow conveyed by the fan exits into the environment outside the tandem roller. Air is sucked in from the environment outside the tandem roller and added to the cooling air flow.The intake duct can, for example, also be arranged in the cover or any other component of the tandem roller, in particular in an area between the driver's cab and the area of ​​the cover facing the driver's cab. Air from the outside of the tandem roller that has not yet been heated by the engine is sucked in through the intake duct. This air sucked in through the intake duct is preferably guided into the flow duct and to the radiator, bypassing the engine compartment. In this way, the radiator is preferably flowed through by a mixture of cooling air that has passed through the engine compartment and cooling air that has not passed through the engine compartment. In particular, when the cooling air in the engine compartment is heated up significantly by the drive motor, the intake duct significantly supports cooling efficiency.In principle, it is also possible to realize the cooling air flow used for cooling the radiator while completely bypassing the engine compartment, in particular by using a cooling air inlet in the longitudinal direction of the machine in the region of the cover that covers the radiator or in the machine area in front of or behind the driver's cab in the longitudinal direction of the machine in which the radiator is arranged. An arrangement of the cooling air inlet between the driver's cab and the cover covering the radiator is also possible. This therefore basically includes an arrangement in which, in particular bypassing the engine compartment, both the cooling air inlet and the cooling air outlet are arranged in the front or rear part of the machine, particularly preferably each formed by one cover.

[0018] As already explained, it is advantageous if the cooling air flow flows through the cooler in an at least partially upward direction. It is particularly advantageous if the cooler is arranged such that the cooling air flow conveyed by the fan flows through it in a direction diagonally upwards and away from the driver's cab. In particular, the ventilation openings through which the cooling air flow conveyed by the fan exits into the external environment of the tandem roller can preferably also be designed such that the cooling air flow conveyed by the fan is directed diagonally upwards and away from the driver's cab as it exits through the ventilation openings. Both the arrangement of the cooler and the design of the ventilation openings therefore ensure that the cooling air or cooling air flow is directed in the same direction, specifically preferably diagonally upwards and away from the driver's cab.For this purpose, guide vanes are arranged in the radiator or at the ventilation openings in the cover, which direct or redirect the airflow accordingly. This allows the cooling airflow to be directed with very little resistance, reducing the required fan power. At the same time, the direction of the cooling airflow away from the driver's cab ensures that the highly heated cooling air coming from inside the tandem roller is distributed into the outside environment without negatively affecting the tandem roller driver. This prevents the ingress of hot cooling air even when the driver's cab window is open.

[0019] The exiting cooling air flow or the targeted arrangement and / or routing of the exiting cooling air flow can be further advantageously configured and integrated into the present system. For example, the exiting cooling air flow can form a flow carpet or flow curtain directed upwards and away from the operator's cab, preventing exhaust gases from the tandem roller from reaching the operator's cab. In particular, the cooling air flow can be directed, for example, via a corresponding arrangement and design of the cooling air outlet and / or through additional guide devices, such as guide vanes, in such a way that it at least partially captures the exhaust gases from the tandem roller and removes them from the operator's cab.For this purpose, it is preferably provided that the ventilation openings through which the cooling air flow conveyed by the fan exits into the exterior environment of the tandem roller and a tailpipe of an exhaust system of the drive engine are arranged on the same cover, and that the ventilation openings are arranged at least partially closer to the driver's cab than the tailpipe. The cooling air outlet openings are thus positioned in the cover in the machine's longitudinal direction between the exhaust outlet of the tailpipe and the driver's cab. The tailpipe refers to the pipe socket from which the exhaust gases of the exhaust system escape ("exhaust"). The tailpipe is arranged further away from the driver's cab than at least some of the ventilation openings through which the cooling air flow exits.In this way, and with the previously described flow direction of the cooling air, the cooling air captures the exhaust gases and at least partially entrains them or at least counteracts the exhaust gases from flowing towards the driver's cab. This works particularly well when an exhaust gas aftertreatment system, such as an SCR system, is used. In this case, a rear silencer is not required, allowing the tailpipe to be designed as a particularly short tailpipe stub. The tailpipe stub is preferably arranged such that it does not protrude vertically beyond the upper edge of the cover or does not completely protrude vertically beyond the cooling air outlet openings in the cover, which is particularly important when the cover slopes downwards away from the driver's cab.In principle, it is preferred if the tailpipe protrudes no more than 30 cm, preferably no more than 20 cm, and particularly preferably no more than 15 cm, from the cover. The outlet opening of the tailpipe is preferably arranged vertically below or at most at the same height as the ventilation openings from which the cooling air exits. It is also particularly advantageous if the tailpipe stub is designed such that the exhaust gases also exit the tailpipe outlet at an angle upwards and in a direction away from the driver's cab. Another particularly advantageous embodiment provides that the tailpipe is surrounded by the ventilation openings through which the cooling air flow escapes, thereby ensuring particularly reliable capture of the exhaust gas flow by the cooling air flow. If the ventilation openings are designed, for example, as a sieve-like sheet, the tailpipe can penetrate this sheet in the middle.

[0020] In principle, the cooler and the fan can be arranged relative to each other in such a way that the fan sucks or pushes the cooling air through the cooler.

[0021] The object mentioned above is also achieved by a method for operating a pivot-steered tandem roller according to the invention, in accordance with the preceding statements, to which reference is hereby made. The same developments, features, effects, and advantages apply to the method according to the invention in a transferred manner as described for the tandem roller according to the invention, and vice versa. Reference is made to the above statements regarding the tandem roller merely to avoid repetition.Specifically, the method according to the invention comprises the following steps: drawing in cooling air from the outside environment of the tandem roller into a front or rear machine compartment; directing the cooling air downwards into an engine compartment and along the longitudinal direction of the machine; directing the cooling air upwards into the other front or rear machine compartment; flowing the cooling air through a cooler arranged in the front or rear machine compartment; and blowing the cooling air out into the outside environment of the tandem roller. By flowing through the cooler in the front or rear machine compartment instead of in the engine compartment as is usual in the prior art, the advantages according to the invention are achieved that the space requirement of the cooler in one of the machine compartments can be optimally met without negatively affecting the size of other components. The cooling air flow is guided and directed through the flow channel already described above.

[0022] A preferred development of the method according to the invention is characterized by the intake of cooling air through an intake duct between a driver's cab and ventilation openings through which the cooling air flow conveyed by the fan exits into the outside environment of the tandem roller. An independent, separate cooling air circuit can also be created via the intake duct, which, for example, leads via the intake duct, through the engine compartment located on this side of the tandem roller, here through the radiator, and then through the ventilation openings in the cover of the engine compartment into the outside environment. In this way, this separate cooling air circuit would bypass the engine compartment and ensure increased cooling efficiency at the radiator.

[0023] For the method, it is also preferred that the cooling air be drawn in and blown out, as well as flowing through the radiator, if possible, in the direction in which the cooling air flow is directed at the respective location, in order to achieve the lowest possible flow resistance. It is therefore preferred that the cooling air be drawn in diagonally downwards and / or that the cooling air flow through the radiator be diagonally upwards and / or that the cooling air be blown out diagonally upwards and away from the driver's cab. Furthermore, the appropriate alignment of the components involved, in particular the radiator and the fan, saves installation space.

[0024] In order to keep the exhaust gas flow of the drive engine away from the driver's cab and the driver of the tandem roller, it is further preferred that the cooling air is blown out into the exterior environment of the tandem roller in such a way that the cooling air flow is directed toward a tailpipe of an exhaust system of the drive engine. In particular, both the cooling air flow and the exhaust gas flow are blown out of the tailpipe in the same direction, with the cooling air flow being blown out at least partially closer to the driver's cab than the exhaust gas flow. In other words, the cooling air flow and the exhaust gas flow are directed together in the exterior environment of the tandem roller, specifically in a direction diagonally upward and away from the driver's cab.

[0025] The invention is explained in more detail below with reference to the exemplary embodiments shown in the figures. They show schematically: Figure 1 : A typical tandem roller in side view; Figure 2: a possible cooling air flow through the tandem roller according to Figure 1 ; Figure 3 : another possible cooling air flow through the tandem roller according to Figure 1 ; Figure 4 : another possible cooling air flow through the tandem roller according to Figure 1 ; Figure 5 : a top view of a possible cooling air duct; Figure 6 : a plan view of another possible cooling air duct; and Figure 7 : a flowchart of the procedure.

[0026] Identical or functionally identical components are identified by the same reference numerals in the figures. Recurring components are not numbered separately in each figure.

[0027] Figure 1shows a pivot-steered tandem roller 1. The tandem roller 1 has a machine frame 3 which is carried by two compactor rollers 5. The compactor rollers 5 are each mounted on the machine frame 3 via a turntable 15 so as to be rotatable about a vertical steering axis. In the machine's longitudinal direction a in the middle of the machine there is an operator's cab 2 which contains, for example, the operating elements of the tandem roller 1 and in which an operator is located during operation of the tandem roller 1. During operation, the tandem roller 1 moves in a forward or backward direction, which without steering angle corresponds to the machine's longitudinal direction a, over the soil 8 and compacts it.

[0028] The Figure 1The side of the tandem roller 1 shown on the left is typically referred to as the front, and the side shown on the right as the rear, even though the tandem roller 1 can work both forwards and backwards and has a comparatively symmetrical structure. Thus, in terms of its basic structure and in particular its frame design, the tandem roller 1 can be divided, for example, into a first steering part 23, a second steering part 24, and a drive and operating part 25. The two steering parts 23, 24 each comprise a compactor roller 5 and part of the machine frame 3. They have, for example, a front cover 16 and a rear cover 17, which each at least partially enclose or surround a front machine compartment 18 and a rear machine compartment 19.It is important that the front and rear steering parts 23 and 24 are designed such that a type of structure, comprising part of the machine frame and a cover, is provided above the respective compactor roller. Between the two steering parts 23, 24 is the central drive and operating part 25. This has the driver's cab 2 and an engine compartment 20 located below the driver's cab, which is bordered on both sides by an engine compartment door 7 transversely to the machine's longitudinal direction a. Viewed vertically, the engine compartment is at the level of the front and rear compactor rollers. Furthermore, the engine compartment is located essentially vertically below the two superstructures described above or the interior spaces covered by the respective cover.

[0029] Fluid tanks 14, for example water tanks, can be accommodated in the engine compartment doors 7. The drive motor 4 is located in the engine compartment 20, between the fluid tanks 14 and the engine compartment doors 7 (see Figures 2-6 ), which is designed, for example, as a diesel combustion engine and can, for example, comprise an exhaust gas aftertreatment device, in particular an SCR device 21.

[0030] A first embodiment of a cooling system according to the invention for the tandem roller 1 is based on Figure 2As shown in the figure, the radiator 10, which is designed, for example, as a hydraulic oil cooler, water cooler, or charge air cooler, or a combination of two or three of these coolers, is arranged in the rear engine compartment 19. Other coolers can also be provided, for example, for an air conditioning system, etc. By arranging the radiator 10 in the rear engine compartment 19, the radiator 10 does not have to be housed in the engine compartment 20 together with the drive motor 4, as is usual. In this way, the space in the engine compartment 20 can be used by other components, for example the SCR device 21. At the same time, however, the radiator 10 can also be designed with a sufficient size, since there is less space constraints in the rear engine compartment 19 than in the engine compartment 20. Furthermore, this allows for particularly efficient cooling air flow, since a significantly improved cooling air flow channel is obtained overall.

[0031] The black arrows in Figure 2the flow direction of the cooling air within the machine frame 3 of the tandem roller 1 is shown. First, cooling air is sucked in from the outside of the tandem roller 1 through ventilation openings 9 on the vertically upper side of the front cover 16 into the front machine compartment 18. From there, the cooling air is transported downwards and rearwards in the longitudinal direction a of the machine into the motor compartment 20. The cooling air flows through this essentially horizontally, i.e. rearwards in the longitudinal direction a of the machine, passing by the drive motor 4. From the motor compartment 20, the cooling air is then transported vertically upwards and further rearwards in the longitudinal direction a of the machine until it reaches the rear machine compartment 19. From there, the cooling air is then blown out through ventilation openings 9 in the rear cover 17 into the outside of the tandem roller 1.The cooling air flow, or rather the conveyance of the cooling air, is achieved by the fan 11, which is driven, for example, by a separate fan drive 12, which in the illustrated embodiment can be a hydraulic drive or an electric drive. The fan 11, together with the cooler 10, is arranged on the second ("rear") steering section 24, specifically in the rear machine compartment 19. It draws the cooling air through the ventilation openings 9 on the first steering section 23 into the front machine compartment 18, from there into the machine compartment 20 in the drive and control section 25, past the drive motor 4, and further in the longitudinal direction a of the machine to the rear into the rear machine compartment 19. From there, the fan 11 blows the cooling air first through the cooler 10 and then through the ventilation openings 9 of the rear cover 17 into the outside environment of the tandem roller 1.In the illustrated embodiment, the fan 11 is arranged upstream of the cooler 10 with respect to the flow direction of the cooling air. However, the cooling air duct could also be designed such that the flow direction of the cooling air is exactly the opposite, i.e., it is sucked in at the rear cover 17 and blown out at the front cover 16.

[0032] Figure 2additionally shows an optional addition and / or alternative solution to the described cooling. Specifically, an intake duct 22 can be formed, through which, in particular, additional cooling air reaches the cooling air duct and the radiator 10, bypassing the engine compartment 20. The intake duct 22 is arranged on the rear or second steering part 24 and runs, for example, likewise through the rear cover 17 or in an area between the driver's cab and the rear cover 17. The cooling air, which is supplied, in particular additionally, through the intake duct 22 and bypasses the engine compartment 20, lowers the temperature of the cooling air flow overall, so that the cooling efficiency of the radiator 10 increases. According to a further alternative embodiment, the air flow through the front engine compartment 18 and the engine compartment 20 is completely dispensed with, and a circuit is created solely via the intake duct 22 and the rear engine compartment 19.In this way, the cooler 10 is flowed through by particularly cool cooling air, so that its efficiency is particularly high.

[0033] Figure 3 shows an alternative embodiment in which, in contrast to the embodiment of the Figure 2 the cooler 10 is arranged upstream of the fan 11 with respect to the flow direction of the cooling air. In other words, the fan 11 sucks the cooling air through the cooler 10 and then blows it out through the ventilation openings 9 of the rear cover 17 into the outside environment of the tandem roller 1. The fan 11 is still arranged together with the cooler 10 in the rear machine room 19 and is operated by a separate fan drive 12. In comparison to the embodiment of the Figure 2 This changes the order of the cooler 10 and the fan 11 with respect to the flow direction of the cooling air.

[0034] In the further alternative embodiment of the invention according to Figure 4The cooler 10 and the fan 11 are no longer arranged in close proximity to one another and in a common interior compartment, as in the previous embodiments, but are spatially separated from one another. Specifically, the fan 11 is arranged on a power take-off 13 of the drive motor 4 and is driven by it, for example via a belt drive. The fan 11 is therefore located in the drive and operating part 25 of the tandem roller 1, specifically in the engine compartment 20. The cooler 10, on the other hand, is still arranged in the rear machine compartment 19, i.e. outside the engine compartment 20. The air flow corresponds to that of the previous embodiments. In this context, it is also possible to position the fan below the front cover and the cooler below the rear cover, or vice versa.

[0035] In all of the exemplary embodiments of the invention shown, the flow direction of the cooling air can generally be reversed. However, it is advantageous if the cooling air is blown out of the same machine part as the exhaust gases from the combustion engine. Specifically, in the tandem rollers 1 shown in the figures, a tailpipe 6 of the exhaust system of the tandem roller 1 is arranged on the second steering part 24, in other words on the rear machine part. The exhaust gases of the drive engine 4 are discharged from the tailpipe 6 into the external environment of the tandem roller 1. The tailpipe 6 also directs the exhaust gases, for example, through the rear cover 17. As shown in the figures, the rear cover 17 slopes away from the driver's cab 2 and drops vertically downwards. Due to the use of the SCR device, the tailpipe 6 can be designed without a rear silencer and can therefore be particularly short.Furthermore, the tail pipe 6 is designed such that the outlet opening for the exhaust gases is located vertically below or at most at the same height as the ventilation openings 9 through which the cooling air exits the machine room 19. The corresponding ventilation openings 9 are in turn arranged closer to the driver's cab 2 than the tail pipe 6. In other words, the ventilation openings 9 are located between the driver's cab 2 and the tail pipe 6. According to an alternative embodiment, it can also be provided that the tail pipe 6 is surrounded on both sides by the ventilation openings 9, particularly when viewed in and / or transversely to the machine's longitudinal direction a. The fan 11, the cooler 10 and the ventilation openings 9, through which the cooling air exits into the outside environment of the tandem roller 1, are designed such that the cooling air is blown out in the direction away from the driver's cab 2 and diagonally upwards.The tailpipe 6 is also designed such that the exhaust gases exit the tailpipe 6 in this direction. In this way, the escaping cooling air forms a flow carpet located between the driver's cab 2 and the tailpipe 6, thus shielding the driver of the tandem roller 1 from the exhaust gases. Due to the higher volume flow and the higher speed of the escaping cooling air compared to the exhaust gas flow, the exhaust gases are also captured by the escaping cooling air flow and transported further away from the driver's cab 2 and distributed into the outside environment. This also leads to a lower exhaust gas exposure for the driver of the tandem roller 1.

[0036] The inventive guidance of the cooling air is also shown again in the Figures 5 and 6 These show a top view of the tandem roller 1, whereby the driver's cab 2 has been omitted for reasons of clarity. Figures 5 and 6illustrate in particular how the cooling air is guided through the tandem roller 1 via the first steering part 23, the drive and operating part 25 and the second steering part 24. For example, a summary of the Figures 1 and 5, how the two liquid tanks 14 arranged on the engine compartment doors 7 are arranged. These are located on opposite sides of the tandem roller 1 and can be pivoted with the engine compartment doors 7. By arranging the liquid tanks 14 in this way, the center of gravity of the tandem roller 1 is particularly low when the liquid tanks 14 are full, which is advantageous for reasons of stability. Furthermore, the liquid tanks 14 can be easily refilled by an operator standing on the floor 8. A key point of the invention is that in order to enlarge the radiator 10, there is no need to reduce the size of the liquid tanks 14, but rather that the radiator 10 is arranged outside the engine compartment 20, specifically in one of the machine rooms 18, 19. In this way, only the cooling air flow needs to be directed through the engine compartment 20 and in particular between the liquid tanks 14.For this purpose, a comparatively small gap between the drive motor 4 and the liquid tanks 14 is sufficient. The flow through the cooler 10 itself then takes place in another area of ​​the tandem roller 1. Figure 6 Furthermore, it is shown by way of example that, in principle, a reverse flow of cooling air through the tandem roller 1 can also be used.

[0037] Figure 7shows a flow diagram of the method 30 according to the invention. The method 30 begins with the intake 31 of cooling air from the external environment of the tandem roller 1 into a front or rear machine compartment 18, 19, preferably into the front machine compartment 18. The cooling air is then directed 32 downwards into the engine compartment 20 and along the machine's longitudinal axis a, preferably to the rear. The cooling air is then directed 33 upwards, preferably to the rear in the machine's longitudinal direction a, into the other front or rear machine compartment 18, 19, preferably the rear machine compartment 19. This is followed by the cooling air flowing 34 through a cooler 10 arranged in the front or rear machine compartment 18, 19, preferably in the rear machine compartment 19, and finally by the cooling air being blown out 35 into the external environment of the tandem roller 1.Optionally, additional cooling air can be drawn in 36 through an intake duct 22 between the driver's cab 2 and ventilation openings 9, through which the cooling air flow conveyed by the fan 11 exits the outside environment of the tandem roller 1. In the method 30 according to the invention, the cooling air can also be blown out 35 in such a way that it is directed toward the exhaust gas outlet from the tailpipe 6 of the exhaust system, thus transporting these exhaust gases away from the driver's cab 2 and actively mixing them with the outside air.

[0038] Overall, the invention optimizes the installation space of the tandem roller 1, particularly in the interior of the machine compartments 18, 19 and the engine compartment 20. This makes it possible to design several components of the tandem roller 1, such as the radiator 10 and the fluid tanks 14, with the largest possible volume, thus increasing the efficiency of the machine. Furthermore, the invention makes it possible to advantageously utilize the cooling air flow to protect the driver of the tandem roller 1 from exhaust gases from the machine.

Claims

1. A pivot-steered tandem roller (1) for ground compaction, comprising - a machine frame (3) with an operator platform (2), - two compaction drums (5) spaced apart in the longitudinal direction (a) of the machine, each of which is steerably mounted on the machine frame (3) via a pivot steering system, - a drive motor (4), - a cooler (10), and a fan (11) associated with the cooler (10) and conveying a cooling air flow, characterized in that the cooler (10) is arranged vertically above and / or in the longitudinal direction (a) of the machine at the level of one of the compaction drums (5), a machine compartment (18, 19) which is at least partially encased by a cover (16, 17) is provided both in front of and behind the operator platform (2) in the longitudinal direction (a) of the machine, the front cover (16) and the rear cover (17) having ventilation openings (9) on their vertically upper side for the cooling air flow conveyed by the fan (11), and that a flow channel is provided which is configured such that the cooling air flow conveyed by the fan (11) is conveyed from the outside environment of the tandem roller (1) into the front machine compartment (18), and from there vertically downward and rearward into an engine compartment (20) arranged below the operator platform (2), then essentially horizontally through the engine compartment (20), from there vertically upward and rearward into the rear machine compartment (19) and from there back into the outside environment of the tandem roller (1), or vice versa.

2. The tandem roller (1) according to claim 1, characterized in that the cooler (10) is arranged vertically above a turntable (15) of the pivot steering system of one of the compaction drums (5).

3. The tandem roller (1) according to any one of the preceding claims, characterized in that the cooler (10) is configured as a cooler package and comprises at least two, in particular all three, of the following coolers: a hydraulic fluid cooler, a coolant cooler, a charge air cooler.

4. The tandem roller (1) according to any one of the preceding claims, characterized in that the fan (11) associated with the cooler (10) has at least one of the following features: - it is arranged vertically above and / or in the longitudinal direction (a) of the machine at the level of one of the compaction drums (5), - it is arranged at a power take-off (13) of the drive motor (4), - it is arranged upstream of the cooler (10) in the flow direction of the cooling air and blows cooling air through the cooler (10), - it is arranged downstream of the cooler (10) in the flow direction of the cooling air and draws cooling air through the cooler (10), - it can be driven by a separate, in particular hydraulic or electric, fan drive (12) or by a power take-off (13) of the drive motor (4), in particular via a belt drive.

5. The tandem roller (1) according to any one of the preceding claims, characterized in that the cooler (10) is arranged in the front machine compartment (18) or in the rear machine compartment (19), and that the fan (11) associated with the cooler (10) is arranged in the front machine compartment (18) or in the rear machine compartment (19), the cooler (10) and the fan (11) associated with the cooler (10) preferably being arranged in the rear machine compartment (19).

6. The tandem roller (1) according to any one of the preceding claims, characterized in that the engine compartment (20) is limited on both sides transversely to the longitudinal direction (a) of the machine by a respective engine compartment door (7), the engine compartment doors (7) each having a liquid tank (14), and that the cooling air flow conveyed by the fan (11) is passed through between the two liquid tanks (14), the cooler (10) being arranged outside the region located between the two liquid tanks (14).

7. The tandem roller (1) according to any one of the preceding claims, characterized in that an intake duct (22) through which air is drawn in from the outside environment of the tandem roller (1) and added to the cooling air flow is arranged between the operator platform (2) and the ventilation openings (9) through which the cooling air flow conveyed by the fan (11) exits into the outside environment of the tandem roller (1).

8. The tandem roller (1) according to any one of the preceding claims, characterized in that the cooler (10) is arranged such that the cooling air flow conveyed by the fan (11) flows through it in an oblique upward direction and away from the operator platform (2).

9. The tandem roller (1) according to any one of the preceding claims, characterized in that the ventilation openings (9) through which the cooling air flow conveyed by the fan (11) exits into the outside environment of the tandem roller (1) are configured such that the cooling air flow conveyed by the fan (11) is directed in an oblique upward direction and away from the operator platform (2) when exiting through the ventilation openings (9).

10. The tandem roller (1) according to any one of the preceding claims, characterized in that the ventilation openings (9) through which the cooling air flow conveyed by the fan (11) exits into the outside environment of the tandem roller (1) and a tail pipe (6) of an exhaust gas system of the drive motor (4) are arranged on the same cover (16, 17), and that the ventilation openings (9) are arranged at least partially closer to the operator platform (2) than the tail pipe (6).

11. The tandem roller (1) according to any one of the preceding claims, characterized in that the cooler (10), in particular the coolers, is / are arranged such that the cooling air flow flows through it / them in an at least partially upward direction.

12. A method (30) for operating a pivot-steered tandem roller (1) according to the preceding claims, comprising the steps of: a) drawing in (31) cooling air from the outside environment of the tandem roller (1) into the front or rear machine compartment (18, 19); b) directing (32) the cooling air downward into the engine compartment (20) and along the longitudinal direction (a) of the machine; c) directing (33) the cooling air upward into the respective other front or rear machine compartment (18, 19); d) passing (34) the cooling air through the cooler (10) arranged in the front or rear machine compartment (18, 19); and e) blowing out (35) the cooling air into the outside environment of the tandem roller (1).

13. The method (30) according to claim 12, characterized by drawing in (36) cooling air through an intake duct (22) between an operator platform (2) and ventilation openings (9) through which the cooling air flow conveyed by the fan (11) exits into the outside environment of the tandem roller (1).

14. The method (30) according to any one of claims 12 or 13, characterized in that the cooling air is drawn in (31) obliquely downward and / or the cooling air is passed through (34) obliquely upward and / or the cooling air is blown out (35) obliquely upward and away from the operator platform (2).

15. The method (30) according to any one of claims 12 to 14, characterized in that the cooling air is blown out (35) into the outside environment of the tandem roller (1) such that the cooling air flow is directed toward a tail pipe (6) of an exhaust gas system of the drive motor (4).