EP3901373B1 - Interchangeable unit for texturing the surface of a floor and road construction machine with such an interchangeable unit - Google Patents

Description

• ein Gehäuse, wobei das Gehäuse in einem Verbindungsabschnitt zur körperlichen Kopplung des Wechselaggregats mit der Straßenbaumaschine Verbindungsformationen zur Verbindung des Wechselaggregats mit einem Maschinenrahmen einer Straßenbaumaschine aufweist, und wobei das Gehäuse in einem vom Verbindungsabschnitt entfernt gelegenen Arbeitsabschnitt eine Arbeitsöffnung aufweist,
• ein Abtragswerkzeug, welches am Gehäuse um eine Arbeitsachse drehbar gelagert ist und von welchem ein Umfangsabschnitt aus der Arbeitsöffnung ragt,
• eine am Gehäuse drehbar gelagerte, mit einem Antriebsriemen koppelbare Antriebs-Riemenscheibe zur funktionalen Kopplung des Wechselaggregats mit der Straßenbaumaschine,
• ein Übertragungsgetriebe, welches Drehmoment und Drehbewegung von der Antriebs-Riemenscheibe unter Umkehrung des Drehsinns zum Abtragswerkzeug überträgt, wobei wenigstens die Drehachse der Antriebs-Riemenscheibe mit Abstand von der Arbeitsachse verläuft.

The present invention relates to an interchangeable unit for removing material from a soil surface, the interchangeable unit being designed for operational physical and functional coupling to a machine frame of a road construction machine, the interchangeable unit comprising:

• a housing, wherein the housing has connection formations for connecting the exchange unit to a machine frame of a road construction machine in a connection section for physically coupling the changeover unit to the road construction machine, and the housing has a work opening in a working section remote from the connection section,
• a removal tool which is mounted on the housing so that it can rotate about a working axis and from which a peripheral section protrudes from the working opening,
• a drive pulley which is rotatably mounted on the housing and can be coupled to a drive belt for the functional coupling of the exchange unit to the road construction machine,
• a transmission gear which transfers torque and rotary motion from the drive pulley to the excavation tool by reversing the direction of rotation, at least the axis of rotation of the drive pulley being spaced from the working axis.

Such an exchange unit with a milling drum as a removal tool is, for example, from DE 10 2012 008 252 A1 known. However, milling drum housings that can be repeatedly and detachably connected to a machine frame of a road milling machine are commonplace.

From the EP 1294991 B2 , the DE 10 2012 024 770 A1 and the DE 10 2012 024 452 A1 milling drum units for road milling machines are also known, which have an additional drive in order to be able to rotate the milling drum independently of the main drive of the milling drum. the DE 10 2012 024 770 A1 and EP 1294991 B2 teach how to use the auxiliary drives for maintenance purposes in order to be able to rotate a milling drum around its working axis at low speed or step by step, so that a worker can check the milling tools distributed on the drum shell of the milling drum and service them if necessary. the DE 10 2012 024 452 A1 teaches accelerating a milling drum with an additional drive to a speed close to its removal speed in normal operation, in order then to engage the main drive without slip and to disengage the additional drive.

From the US8056549B1 a soil cultivating machine of its own kind is known, which has a cutting roller with a plurality of cutting discs as the removal tool, which are arranged at an axial distance from one another with respect to the working axis of the removal tool. This cutting roller, referred to as a "grooving roller", is used for surface texturing of a floor, for example for the grooving of a floor surface. In contrast to the milling drums mentioned above, which completely remove a soil surface over their working width up to a set milling depth along the feed path of the milling drum, when using a grooving roller or a surface-texturing roller in general, a defined surface profile of the soil to be worked is generated as a work result . As a rule, this means that over the working width of the surface-texturing roller, only part of the soil surface is removed in a defined manner, while another part of the soil surface remains in its original state.

The known from the prior art milling exchange unit mentioned above with a detachably mountable and attachable milling drum has at least a significant part of the transmission gear in an inner tube, which accommodates the material-removing milling drum for the removal operation and which is surrounded radially on the outside by the milling drum when it is ready for operation. The transmission gear is therefore located on the one hand in the torque path between the drive pulley as the only pulley projecting on the housing of the known milling/changing unit and the milling drum, and on the other hand it is surrounded radially on the outside by the milling drum.

Due to the low cutting speeds, which are about 10 ms ^-1 or less, and the relatively large cutting circle diameter of milling drums in the range of about 0.8 m to 1.2 m, the transmission gear of the known milling exchange unit is a speed reduction gear, which Significantly higher speed of the drive motor of the milling drum. The planetary gear required for the typical speed reduction ratios of road milling machines in the range of 18:1 to 21:1 is complex to manufacture and assemble, but is advantageously located radially inside the milling drum tube carrying the milling cutters, in the case of exchangeable milling drums even inside the permanent working axis inner tube rotatably mounted on the housing of the changing unit.

However, if the rotating excavation tool has an internal recess with a clear width of less than 50 cm, such an excavation tool can no longer be accommodated by a conventional interchangeable unit, as described at the outset, since such an excavation tool when attempting to attach it to the Bringing the change-over unit ready for use would inevitably collide with the conventional transmission gear before it would even come close to being ready for use.

The surface-texturing removal tools described above usually work at significantly higher cutting speeds than milling drums. In order to avoid undesirably high moments of inertia of such removal tools acting around the working axis, these are designed with significantly smaller cutting circle diameters than conventional milling drums. That's what their speed is for significantly higher than the removal speed of conventional milling drums during their intended removal operation.

It is the object of the present invention to provide a technical teaching that makes it possible to use conventional road milling machines, which are designed on the machine frame side for milling off ground surfaces using milling drums equipped with individual milling tools, for other types of soil cultivation, in particular for texturing ground surfaces.

This object is achieved by the present invention with an interchangeable unit of the type mentioned at the outset, in which a working shaft arrangement passes through a housing wall of the housing, the working shaft arrangement connecting the removal tool to a working gear component arranged on the side of the housing wall facing away from the removal tool for common rotation in the same direction, wherein the transmission gear is arranged between the drive pulley and the work gear component.

The interchangeable unit according to the invention therefore has not only the drive belt pulley, but also a working gear component in addition to this, which is shielded from the removal tool by the housing wall. The transmission gear can thus transmit torque from the drive pulley to the work gear component with a desired transmission ratio while reversing the direction of rotation. Finally, by means of the working shaft arrangement, the working gear component transmits the torque and the rotational movement transmitted by the transmission gear simply and efficiently as a rotational movement in the same direction to the removal tool.

A removal tool with significantly smaller dimensions, in particular smaller radial dimensions with respect to the working axis, can thus also be accommodated in the exchange unit and driven via the drive belt pulley. The drive pulley is connectable to a drive power source of a road construction machine originally designed as a road milling machine. Then Road milling machines also transmit torque between their power source and the drive pulley of the milling sub-assembly with a drive belt. The exchange unit of the present application thus uses the road construction machine-side devices for torque transmission and allows a coupling to them. Thus, a road milling machine, to which a conventional milling interchangeable unit with a milling drum accommodated therein is initially coupled, can be converted by replacing the conventional milling interchangeable unit with the above-described interchangeable unit for tillage other than milling. Of course, this also applies in the opposite direction for a conversion from soil processing other than milling to milling.

Since the excavation tool of the interchangeable unit of the present application on the one hand usually has significantly smaller radial dimensions with respect to the working axis than a milling drum, but on the other hand has to be brought into contact with the soil to be worked, the otherwise comparable dimensions of the housing of known interchangeable milling units are on the one hand and the housing of the present exchange unit, on the other hand, the working axis of the exchange unit of the present application is at a greater distance from the connecting portion of the housing than the milling axis of a milling exchange unit with a milling drum. The roughly the same dimensions of the housing of the milling/interchangeable unit and of the present interchangeable unit are based on their connectivity with and their intended use on one and the same machine frame of a road construction machine for a respective tillage.

It is not excluded that the working shaft arrangement comprises a plurality of drive shafts, for example as a working shaft train, for example with any countershaft, which are connected to one another in a torque-transmitting manner. However, for reasons of simple manufacture and assembly and reduced susceptibility to damage, a single working shaft is preferred as the working shaft arrangement. which rigidly connects the work gear component to the removal tool for rotation at the same speed and in the same direction.

In principle, the working gear component can be any gear component, such as a gear, in particular a spur gear, or even a friction wheel. However, the working gear component is preferably a working pulley. Then, for example, according to a first, less preferred embodiment, a drive belt driven by a motor on the machine frame for revolving movement can transmit torque to the work pulley. The drive pulley is essentially needed to support the drive belt on it. The drive belt is then supported with its radially inner inner surface pointing towards the volume enclosed by the drive belt on the drive pulley and rests with its opposite radially outer outer surface on the working pulley in a torque-transmitting manner. Then the drive pulley, the work pulley and the drive belt form the transmission gear, since the abutment of said pulleys on opposite sides of the drive belt causes a reversal of the sense of rotation, so that the work pulley rotates in the opposite sense compared to the drive pulley . By selecting the diameter of the working pulley and an output pulley on the machine frame side that can be driven by a source of drive power on the machine side, a speed transmission ratio between the drive power output on the machine frame side and the removal tool can be adjusted within certain limits.

In order to achieve the largest possible wrap angle of the working pulley, a further pulley can be provided in such a way that the working pulley is located between the drive pulley and the further pulley.

Because of the relatively large length of the drive belt required, this configuration of the removable frame is possible, but not preferred.

However, the configuration of the working transmission component as a working pulley has the further advantage that a separate working belt drive can be designed and arranged on the changing unit, which can remain permanently on the changing unit. Belt drives have proven themselves as a means of transmitting torque on road construction machinery.

In a more concrete constructive embodiment of the aforementioned working belt drive, the transmission gear can have an intermediate pulley, a first coupling device and a working belt as the second coupling device, the first coupling device coupling the drive pulley and the intermediate pulley to one another in a torque-transmitting manner and the working belt connecting the intermediate Pulley and the working pulley coupled together in a torque-transmitting manner. From the outside, only the specified pulleys are then preferably recognizable on the housing: drive pulley, intermediate pulley, working pulley and the working belt.

A simple way of realizing the reversal of the direction of rotation required by the transmission gear can be achieved in that the transmission gear has a gear stage with an even number of meshing gears as the first coupling device, so that the direction of rotation is reversed in the entire gear train. For example, with four gears, a relatively large center distance can be bridged with an equally relatively small installation space of the gear gear stage, since each of the four gears can be designed with a smaller diameter than if the same center distance were bridged by only two gears. For reasons of the lowest possible number of components and thus the lowest possible assembly effort, the gear-gear stage can have exactly two meshing gears. The gearwheels of the gearwheel transmission stage are preferably spur gearwheels, so that the gearwheel transmission stage, in relation to the gearwheel axes of rotation, takes up as little axial space as possible. The axes of rotation of the gear wheel are preferably parallel to the working axis.

Since the removal tool, compared to conventional milling drums and their cutting circle diameter of between 0.8 m and 1.2 m, preferably has a significantly smaller cutting circle diameter of 0.6 m or less, the gear wheel gear stage can be completely radial - with regard to the working axis - without any problems. be arranged outside of the radial extent of the removal tool. This eliminates the need, which exists with interchangeable milling units, to arrange the transmission gear or parts thereof radially inside the removal tool. Since the transmission gear does not have to fit into the removal tool, the designer of the exchange unit is not subject to the spatial restrictions known for milling exchange units when designing the transmission gear.

In order to make the best possible use of the axial dimensions of the interchangeable unit along the working axis for picking up cutting tools that remove soil material and to achieve the largest possible working width for a given dimension of the interchangeable unit, the toothed wheel gear stage is preferably arranged axially - with respect to the working axis - with the axial extension area of the removal tool overlapping . This axially overlapping arrangement is facilitated in particular by the complete arrangement of the gearwheel gear stage radially outside of the removal tool.

Then, in contrast to interchangeable milling units, in which the distance between the drive-side housing wall and the nearest end face of the milling drum is often considerably greater than the distance between the zero-side housing wall and the opposite end face of the milling drum because of the speed reduction gear located at least in sections radially inside the milling drum , the removal tool must be brought about equally close to the respective housing walls on the drive side as well as on the neutral side.

Soil processing that removes soil material inevitably leads to an aggressive, particle-loaded immediate environment of the removal tool during the intended removal operation. The rotating removal tool has a high kinetic energy during the excavation operation, which it transfers to particles removed from the ground. In order to prevent the gear stage from being impaired or even damaged by the aggressive, abrasive environment of the removal tool, the gear stage is preferably physically shielded from the removal tool. The gearwheel gear stage is preferably accommodated in a gear stage housing which encloses the gearwheel gear stage on all sides. In this way, the gear stage can be easily transported, stored and exchanged as an assembly that is housed on all sides, together with its housing. A simplification in construction by reducing the required number of components can be achieved in that one wall of the gear stage housing is also a wall of the housing of the exchange unit.

The drive pulley and the working gear component, in particular as a working pulley, more preferably also the intermediate pulley, are preferably all arranged on the same wall of the housing of the changing unit and protrude from this to the same side. Road construction machines generally have a drive end from which torque is supplied to and introduced into the removal tool. The so-called zero side is opposite the drive side along the working axis. The housing wall, from which the working gear component and said belt pulleys protrude, is preferably the drive-side wall of the changing unit. Because of the physical proximity to the drive belt pulley and the intermediate belt pulley, the toothed gear stage is also preferably arranged on this wall. The drive-side wall of the changing unit can therefore also be a wall of the gear stage housing.

In order to utilize the space available in the housing of the exchange unit, the gear stage is preferably located on the same side of the wall of the exchange unit as the removal tool, i.e. on the opposite side of the wall from which the drive pulley, the working gear component and, if necessary also protrude the intermediate pulley. To achieve a compact design, a gear of the gear stage is connected to the drive pulley for rotation in the same direction and at the same speed, and another gear is connected to the intermediate pulley for rotation in the same direction and at the same speed. The two gears mentioned are preferably each connected to the belt pulleys mentioned by a rigid shaft. Depending on the center distance between the drive pulley axle and the intermediate pulley axle to be bridged by the gear-gear stage, the two gears directly coupled to the respective pulleys can be the only gears in the gear-gear stage, or there can be an even number of other gears for torque transmission between the gears be arranged.

Removal tools with smaller cutting circle diameters than the known milling drums often rotate at higher speeds than milling drums when used for their intended purpose. Therefore, unlike with milling drums, it is not necessary to greatly reduce the drive belt speed supplied by the road construction machine on the machine frame side. The toothed gear stage therefore preferably has a speed transmission ratio of between 0.3 and 5, compared to a speed reduction ratio of about 20:1 for milling drums. Speed transmission ratios close to one are preferred, ie preferably between 0.5 and 2, particularly preferably between 0.75 and 1.5. The choice of the exact speed transmission ratio of the gear transmission stage also depends on the selected diameters of the pulleys involved in the torque transmission path, but a speed transmission ratio of between 0.9 and 1.3 is particularly preferred, as this allows the use of approx gears of the same size in the gear gear stage. Preferably, the speed transmission ratio differs at least slightly from 1, in order to prevent the same teeth always being in mesh with each other in pairs per gearwheel revolution, which can lead to undesirably high wear of the tooth flanks.

What was said in the previous paragraph about the speed transmission ratio of the gear stage applies when the gear stage has more than two gears, preferably for the speed transmission ratio of each pair of gears.

The removal tool, which usually rotates faster than known milling drums, has a cutting speed of between 20 and 80 ms ^-1 , preferably between 29 and 62 ms ^-1 , when operated as intended.

In principle, the removal tool can be any removal tool for surface texturing of a ground surface that removes ground material. The removal tool is preferably a cutting roller for working soil surfaces with grooves. Such cutting rollers are also known in the prior art as “grooving rollers” or also as “grinding rollers”. Such rollers can have cutting discs in succession along the working axis, optionally with the interposition of spacer elements defining the axial distance, which are provided with cutting edges along their circumference. These cutting discs often have geometrically undefined cutting edges due to grain bonded to their outer surface, such as ceramic grain or diamond.

Since the excavation tools of the interchangeable unit presented here rotate at comparatively high speeds during intended excavation operation, it can be advantageous for the drive train to reach the operating speed in a manner that is as gentle as possible if the interchangeable unit has a starting motor which, with the interposition of a starting clutch, can be separated and torque-transmittingly connected to the removal tool stands. The starting motor can then accelerate the removal tool from a standstill to a first limit speed, from which a motor on the machine frame takes over the further rotary drive of the removal tool. The starting motor can then be separated from the drive train of the removal tool by the starting clutch, so that an undesirable dragging of the starting motor by the machine frame side Motor can be avoided as the main drive of the removal tool. A freewheel is also considered to be a starting clutch within the meaning of the present application.

The starting clutch is preferably a separate switchable clutch device which is arranged in the drive train between the starting motor and the removal tool. However, the starting clutch can be realized with the already existing components by the working belt and a working belt tensioner changing the tension of the working belt. For this purpose, the working belt tensioner can have a tensioning roller and an actuator that displaces the tensioning roller.

Likewise, the starting motor can support a braking of the removal tool in a desired deceleration or drag operation. In such a drag operation with decreasing speed of the removal tool, for example from the first limit speed mentioned and below, the removal tool drives the starting motor, so that its resistance to movement gradually brakes the removal tool.

The starting motor can be coupled to an energy store, preferably an on-board energy store of the interchangeable unit, with which the starting motor is connected for energy transmission. The starting motor can receive energy from this energy store during acceleration operation. During deceleration operation of the starter motor, the starter motor can store energy back into the energy store.

For example, the starting motor can be a hydraulic starting motor, which acts as a hydraulic pump during towing operation. Alternatively, the starting motor can be an electric motor, which works as a generator or as an eddy-current brake in towing mode. Depending on the type of starting motor, the energy store can be a hydraulic energy store or an electrical energy store.

The changing unit preferably has at least one hydraulic quick-release coupling, particularly preferably in the connecting section, in order to have one on the changing unit side To be able to connect the hydraulic line quickly and easily to a hydraulic line on the machine frame side of the road construction machine and thus, for example, to be able to ensure a supply of a hydraulic start-up motor with hydraulic oil on the machine frame side.

Additionally or alternatively, the exchange unit has, preferably in the connecting section, an electrical connection device, such as at least one plug and/or at least one socket, in order to quickly and easily connect an electrical line on the exchange unit to an electrical line on the machine frame and thus, for example, supply an electrical To be able to ensure the starting motor with electrical energy provided on the machine frame side and/or to electrically connect sensors and/or actuators arranged on the changing unit to the control of the road construction machine.

The starting motor is preferably accommodated in the housing of the changing unit and is thus protected from external influences. There it is preferably shielded from the aggressive environment of the removal tool, for example by a partition wall arranged between the starting motor and the removal tool. Like the gear stage, the starting motor can be accommodated in a separate starting motor housing. At least one wall of the starting motor housing is preferably a common wall either with the gear stage housing or with the housing of the changing unit. The starting motor can be in direct, torque-transmitting connection with the drive pulley or with the intermediate pulley using short connection paths, ie only with the intermediate arrangement of the starting clutch. When the intermediate pulley is provided, the starting motor is preferably connected directly to it in a torque-transmitting manner, so that the torque transmission path from the starting motor to the removal tool is as short as possible.

• einen Maschinenrahmen,
• ein Fahrwerk mit wenigstens drei Laufwerken, welche abrollbar auf einem Untergrund aufstehen,
• einen Motor mit einer Ausgangswelle, an welcher Drehmoment abgreifbar ist,
• eine vom Motor antreibbare Ausgangs-Riemenscheibe,
• Verbindungsgegenformationen zur Verbindung des Maschinenrahmens mit einem Wechselaggregat nach einem der vorhergehenden Ansprüche,
• ein Wechselaggregat, wie es oben beschrieben und weitergebildet ist, wobei das Wechselaggregat mittels seiner Verbindungsformationen und der Verbindungsgegenformationen des Maschinenrahmens lösbar mit dem Maschinenrahmen verbunden ist, und
• einen Antriebsriemen, welcher die Ausgangs-Riemenscheibe mit der Antriebs-Riemenscheibe drehmomentübertragend verbindet.

The present invention also relates to a self-propelled road construction machine, comprising:

• a machine frame,
• a chassis with at least three running gears, which stand up on a surface so that they can be rolled,
• a motor with an output shaft at which torque can be tapped,
• an output pulley drivable by the engine,
• Connecting counter-formations for connecting the machine frame to a changing unit according to one of the preceding claims,
• an interchangeable unit as described and developed above, the interchangeable unit being detachably connected to the machine frame by means of its connecting formations and the connecting counter-formations of the machine frame, and
• a drive belt torque-transmittingly connecting the output pulley to the drive pulley.

A rotary bearing of the output pulley is permanently fixed directly or indirectly to the machine frame with the interposition of at least one other component or another assembly.

The connecting formations and connecting counter-formations are preferably form-fitting means that cooperate with one another, such as hooks, bolts and/or bolts on the one hand and eyelets, openings and/or recesses on the other hand, with the respective hook, bolt or bolt engaging behind the associated eyelet, opening or recess when the connection is established, intersperses or interferes with the formation in question. Eyelets, openings and/or recesses behind which connecting counter-formations engage are preferably formed in the connecting section of the housing of the interchangeable unit or firmly connected to it. The components that reach behind, such as hooks, bolts or bolts, are preferably arranged on the machine frame or firmly connected to it because of the easier automated adjustability. In addition or as an alternative, openings can be formed both in the machine frame and in the housing of the changing unit, which are aligned with one another in the connected state and are coupled with one another by bolts which pass through both aligned openings. Bolts like that can be removable from both the machine frame and the changing unit. The connection counter-formations can be driven with actuators to facilitate the establishment of a connection between the machine frame and exchange unit for an engagement movement, since the connection counter-formations permanently connected to the machine frame can be supplied with energy from the road construction machine more easily than the connection formations arranged on the exchange unit.

In principle, the output shaft of the motor can directly carry the output pulley. However, the engine, in particular a diesel engine, is often used as the power plant of the road construction machine in order to supply different aggregates of the road construction machine with energy. A transmission, preferably with at least one power take-off, is therefore preferably arranged between the output pulley and the output shaft of the motor. A pump distributor gear is preferably arranged between the motor and the output pulley, so that starting from the output shaft, energy converters, such as hydraulic pumps and possibly electric generators, and also the removal tool can be driven. The pump distributor gear can be a switchable pump distributor gear in order to be able to produce different operating states on the output pulleys. In a first switching state, the pump transfer case can preferably connect the output pulley to the output shaft of the motor in the same direction and at the same speed, and in a second switching state that differs from the first, the output pulley can connect in the same direction and at a speed that is changed by a speed transmission ratio compared to the speed of the output shaft connect to the output shaft.

In order to be able to change the speed transmission ratio between the motor of the road construction machine and the drive pulley to a greater extent, the road construction machine can have at least two output pulleys of different diameters, which can be exchanged for one another. One of the output pulleys is coupled to the engine as a rotary drive, at least one other is carried along on the road construction machine, such as in a storage room. If necessary, a transmission ratio can also be adjusted if the road construction machine is converted between different types of tillage by exchanging between a milling exchange unit and an exchange unit of the present application.

The use of a belt drive allows the ability to transmit torque to be varied by changing the belt tension. Thus, the belt drive itself can be used as a kind of slip clutch. For this purpose, the road construction machine preferably also has a displaceable drive belt tensioner, which can be displaced to change the tension of the drive belt.

• Schalten der Anlaufkupplung in einen oder/und Halten der Anlaufkupplung in einem drehmomentübertragenden Verbindungszustand, wenn das Abtragswerkzeug mit einer Drehzahl dreht, die kleiner ist als oder gleich ist wie eine erste Grenzdrehzahl, wobei die erste Grenzdrehzahl kleiner ist als die Abtragsdrehzahl des Abtragswerkzeugs bei bestimmungsgemäßem Abtragsbetrieb,
• Schalten des Antriebsriemenspanners in einen oder/und Halten des Antriebsriemenspanners in einem Betriebszustand, welcher eine Leerlaufspannung des Antriebsriemens bewirkt, welche geringer ist als die Betriebsspannung des Antriebsriemens bei bestimmungsgemäßem Abtragsbetrieb des Abtragswerkzeugs, wenn das Abtragswerkzeug mit einer Drehzahl dreht, die kleiner ist als eine zweite Grenzdrehzahl, wobei die zweite Grenzdrehzahl kleiner ist als oder gleich ist wie die erste Grenzdrehzahl,
• Verändern der Spannung des Antriebsriemens zwischen der Leerlaufspannung und einer näher bei der Betriebsspannung gelegenen Riemenspannung, vorzugsweise der Betriebsspannung, gleichsinnig mit der Drehzahl des Abtragswerkzeugs zwischen der zweiten Grenzdrehzahl und der Abtragsdrehzahl, d. h. die Spannung des Antriebsriemens wird mit der Zeit erhöht, wenn die Drehzahl des Abtragswerkzeugs mit der Zeit ansteigt und umgekehrt.

If the road construction machine has an interchangeable unit with a starter motor designed as described above, the starter motor and the starter clutch connecting the starter motor to the removal tool being controllable by a control device of the road construction machine, the road construction machine is preferably designed to use the following method for acceleration or deceleration of the rotation of the cutting tool:

• Switching the start-up clutch into and/or holding the start-up clutch in a torque-transmitting connection state when the removal tool rotates at a speed that is less than or equal to a first limit speed, the first limit speed being less than the removal speed of the removal tool during intended removal operation ,
• Switching the drive belt tensioner to and/or holding the drive belt tensioner in an operating state that causes an idle tension of the drive belt that is less than the operating tension of the drive belt during intended removal operation of the removal tool when the removal tool rotates at a speed that is less than a second Speed limit, the second speed limit being less than or equal to the first speed limit,
• Varying the tension of the drive belt between the idle tension and a belt tension closer to the operating tension, preferably the operating voltage, co-directional with the speed of the excavation tool between the second limit speed and the excavation speed, ie the tension of the drive belt is increased over time as the speed of the excavation tool increases over time and vice versa.

The first limit speed can be 50% or less of the removal speed. Since starting from idle requires a particularly high torque, it is sufficient if the starting motor supports the motor of the road construction machine on the machine frame side in a speed range of the excavation tool that is close to standstill and preferably contains a speed of zero. It can therefore be sufficient if the first limiting speed does not fall below 5% or 10% or even 15% of the removal speed. For the reasons mentioned, it can also be sufficient if the first limiting speed does not exceed 30%, preferably 25%, of the removal speed.

During an acceleration process, in which the speed of the removal tool increases, the starting clutch is first brought into a connected state and held in this state, so that the starting motor can accelerate the removal tool. During this phase, the tension of the drive belt is the no-load voltage at least up to the second limit speed, possibly up to the first limit speed, so that the starting of the excavation tool does not disturb the motor of the road construction machine and vice versa. Then, when the speed of the excavation tool exceeds the first limit speed, the excavation tool is driven solely by the engine of the road construction machine via the drive belt. In this phase, the drive belt tensioner reaches an operating state in which it keeps the drive belt under operating tension, at the latest at the beginning of the removal operation. When the cutting speed is reached, but before the start of a cutting operation, a lower belt tension than the operating voltage can be sufficient due to the lower load on the rotating cutting tool. In order to be able to transfer the excavation tool smoothly from the starting motor to the engine of the road construction machine during an acceleration process, the drive belt tensioner can be shifted after the second limit speed has been reached and exceeded in such a way that the tension of the drive belt gradually increases from the no-load voltage to the operating voltage.

A deceleration process of the excavation tool runs in the opposite direction. Starting from the cutting speed, the speed of the cutting tool is reduced until the starting motor is connected to the cutting tool via the starting clutch from the first limit speed, so that the cutting tool drives the starting motor in drag mode and is braked by it. The drive belt tensioner may be relocated such that the tension of the drive belt gradually approaches the no-load tension when the speed of the excavation tool reaches the second limit speed.

Unlike when accelerating the cutting tool, when decelerating the cutting tool, the belt tension in the drive belt can alternatively be maintained as the operating voltage, so that the cutting tool to be decelerated has to overcome the highest possible drag torque or is coupled with the highest possible mass moment of inertia. Since the motor of the road construction machine is operated at the most constant speed possible, the motor can preferably be separated from the output pulley by a separate clutch.

The first limit speed is usually specified structurally by the starting motor. For example, the first limit speed can be a maximum operating speed of the starting motor or its rated speed.

• einen Maschinenrahmen,
• ein Fahrwerk mit wenigstens drei Laufwerken, welche abrollbar auf einem Untergrund aufstehen,
• einen Motor mit einer Ausgangswelle, an welcher Drehmoment abgreifbar ist,
• Verbindungsgegenformationen, welche zur Verbindung des Maschinenrahmens mit Verbindungsformationen von wenigstens zwei unterschiedlichen Wechselaggregaten mit je einem Abtragswerkzeug ausgebildet sind, wobei die Abtragswerkzeuge zu Abtragsbearbeitungen unterschiedlicher Abtragsart ausgebildet sind, und
• eine Drehmoment-Übertragungskopplung, welche zur Herstellung einer lösbaren drehmomentübertragenden Verbindung zwischen dem Motor und dem Abtragswerkzeug des jeweils über die Verbindungsgegenformationen verbundenen Wechselaggregats ausgebildet ist.

In its basic idea, the present invention also relates very generally to a self-propelled road construction machine that can be converted to carry out its type of removal after different removal processing, which for this purpose comprises:

• a machine frame,
• a chassis with at least three running gears, which stand up on a surface so that they can be rolled,
• a motor with an output shaft at which torque can be tapped,
• Connection counter-formations, which are designed to connect the machine frame to connection formations of at least two different exchangeable units, each with a removal tool, the removal tools being designed for removal processing of different types of removal, and
• a torque transmission coupling, which is designed to produce a detachable, torque-transmitting connection between the engine and the removal tool of the exchange unit connected via the connecting counter-formations.

The torque transmission coupling may include the drive belt described above as one possible embodiment of a torque transmission coupling. The loosening of the torque-transmitting connection can require a tool in order to be able to transmit the highest possible amount of torque via the coupling.

Different types of removal, such as milling on the one hand and texturing of surfaces on the other hand, are to be distinguished from similar removal processes with different dimensions, such as milling with milling drums of different working widths and/or different tool spacing.

The road construction machine can preferably be equipped for milling soil surfaces by connecting its machine frame to a milling/interchangeable unit known per se, and can be equipped for surface-texturing soil tillage of soil surfaces by connecting its machine frame to an interchangeable unit. The interchangeable unit for surface-texturing tillage can be configured as described above or can be as described above be an exchange unit. However, it can also deviate structurally from the interchangeable unit described above.

To ensure that it can be set up, the road construction machine can include a milling exchange unit and another exchange unit for surface-texturing soil processing, only one of which can be connected to the machine frame at the same time.

With regard to possible further developments of the machine frame, chassis, engine and connecting counter-formations, what was said above also applies to the present road construction machine.

Figur 1

eine grobschematische Seitenansicht in Maschinenrahmenquerrichtung einer erfindungsgemäßen Straßenbaumaschine in beispielhafter Gestalt einer Großfräse, wobei der Maschinenrahmen der Straßenbaumaschine mit einem erfindungsgemäßen Wechselaggregat verbunden ist,

Figur 2

eine grobschematische Draufsicht auf eine Zahnrad-Getriebestufe am Wechselaggregat der Straßenbaumaschine von Figur 1, und

Figur 3

eine grobschematische perspektivische Ansicht des Wechselaggregats der Straßenbaumaschine von Figur 1 in Alleinstellung.

The present invention is explained in more detail below with reference to the accompanying drawings. It shows:

figure 1

a rough schematic side view in the transverse direction of the machine frame of a road construction machine according to the invention in the exemplary form of a large milling machine, the machine frame of the road construction machine being connected to an interchangeable unit according to the invention,

figure 2

a rough schematic plan view of a gear stage on the changing unit of the road construction machine figure 1 , and

figure 3

a rough schematic perspective view of the exchange unit of the road construction machine figure 1 alone.

The viewer of figure 1 looks at the road construction machine or "machine" 10 for short, shown only roughly schematically, in the direction of the plane of the drawing figure 1 orthogonal machine frame transverse direction Q. The machine frame longitudinal direction is denoted by L and runs parallel to the plane of the drawing figure 1 . The machine height direction H also runs parallel to the plane of the drawing figure 1 and orthogonal to the machine and cross-machine directions L and Q, respectively. The arrowhead the machine frame longitudinal direction L in figure 1 points in the forward direction. In case of doubt, the machine frame height direction H is parallel to the direction of the lifting columns 14 or 16. The machine height direction H runs parallel to the yaw axis Gi of the machine 10, the machine longitudinal direction L runs parallel to the roll axis Ro and the machine transverse direction Q runs parallel to the pitch axis Ni.

The road construction machine 10 can have a control station 24 from which a machine operator can control the machine 10 via a control panel 26 . A control device 27 of the road construction machine 10 operated from the control desk 26 can be accommodated in the control panel 26, which controls the switching and working processes on the road construction machine 10 mentioned in the present application through control intervention by an operator and/or on the basis of preprogrammed control program sequences. For this purpose, the control device 27 has at least one integrated circuit and a data memory connected thereto for data transmission.

Under the machine frame 12 is only dashed and only in figure 1 a changing unit 28 is indicated, here by way of example as a device 28 for texturing soil surfaces with a groove cutting roller 32 accommodated in a housing 30 of the changing unit 28, which extends along the machine frame transverse direction Q and is rotatable about a working axis R running in the machine frame transverse direction Q, in order to to be able to cut grooves into soil material starting from the contact surface A of the soil U with a cutting depth determined by the relative height of the machine frame 12 . Such a grooved-texturing surface treatment can serve to reduce the generation of rolling noises on the contact surface A and/or to ensure a defined drainage of precipitation and/or to increase the amount of precipitation that can be drained off per unit of time.

The height adjustability of the machine frame 12 by the lifting columns 14 and 16 therefore also serves to set the cutting depth or, in general, the working depth of the machine 10 when working the soil. It is the one shown as an example Soil cultivating machine 10 is a large road milling machine for which the arrangement of the interchangeable unit 28 in the longitudinal direction L of the machine frame between the front and rear drives 18 and 20 is typical. Such large road milling machines or also soil-removing machines in general usually have a conveyor belt in order to transport removed soil material away from the machine 10 . A conveyor belt, which is also fundamentally present in machine 10, is shown in Fig figure 1 not shown. For the present surface texturizing tillage, for which the in 1 shown road building machine 10 is immediately set up, no conveyor belt is required due to the resulting, compared to a milling small amount of removed soil material. The removed material is bound by water and sucked out of the housing 30, which is advantageously under negative pressure.

In the side view of figure 1 It cannot be seen that the machine 10 has two lifting columns 14 and 16, each with a running gear 18 and 20 connected thereto, both in its front end area and in its rear end area. The lifting columns 14 are coupled to the carriage 18 in a manner known per se by means of a coupling structure 34 . The rear lifting columns 16 are connected to their respective carriage 20 via a coupling structure 36 which is constructed identically to the coupling structure 34 . The drives 18 and 20 are constructed essentially identically and form the chassis 22 of the machine.

In the example shown, the carriage 18 with a possible running direction indicated by the double arrow D has a radially inner receiving structure 38 on which a revolving running chain 40 is arranged. Deviating from the chain drives 18 and 20 shown, the drives 18 and/or 20 can also be designed as wheel drives.

Each of the lifting columns 14 and 16, and with them the drives 18 and 20, can be rotated about a steering axis S by a steering device that is not shown in detail. The exchange unit 28 can be exchanged for a milling exchange unit. The road construction machine 10 carries a milling/interchangeable unit with a milling drum during most of its excavation operation. through the in figure 1 The changeover unit 28 shown in a roughly schematic manner, for example for grooved surface processing, can be used to expand the range of processing that can be carried out by the road construction machine 10. By arranging the interchangeable unit 28 with the groove cutting roller 32 mounted therein, the large road milling machine 10, which previously only performed milling, becomes a road construction machine 10, which also performs surface texturing.

On its side pointing towards the machine frame 12, the housing 30 has a connecting section 30a, by means of which the changing unit 28 is connected to the machine frame 12. The connecting section 30a has lugs 44 with through holes 47 as connecting formations 42 (see Fig. 3 ), which are penetrated by bolts 46 in the example shown. The bolts 46 also pass through connecting counter-formations 48 of the machine frame 12, which also have through-holes. The connection counter-formations 48, like the connection formations 42, are designed as lugs 50 for better accessibility for workers who insert and tighten the screw bolts 46. The number of tabs 44 and 50 as well as the screw bolt 46 can and is usually also determined by the figure 1 number shown may differ.

At its lower end region along the yaw axis Gi opposite the connecting section 30, the housing 30 or the exchange unit 28 has a working section 30b with a working opening 30c, through which the groove-cutting roller 32 protrudes in order to come into material-removing contact with the ground U .

An internal combustion engine 52 mounted on the machine frame 12 with a crankshaft 53 running along the pitch axis Ni as an engine output shaft is indicated in dashed lines on the road construction machine 10, with the crankshaft 53 on the output side is coupled to a preferably switchable pump transfer case 54, which is also roughly indicated only by dashed lines. A transmission output shaft 55 of the pump transfer case 54 coaxial with the axis of rotation of the crankshaft 53 carries an output pulley 56 which rotates about an output pulley axis P56 parallel to the pitch axis Ni.

The output pulley 56 uses the driving force of the motor 52 transmitted to it by the pump distributor gear 54 to drive a revolving drive belt 58 which can be tensioned via a drive belt tensioner 60 with a variable tensioning force. For this purpose, the drive belt tensioner 60 has a tensioning roller 60a lying against the inner circumference of the drive belt 58, which can be displaced against the inner circumference of the drive belt 58 and away from it via a piston-cylinder arrangement 60b as an actuator. By changing the tension of the drive belt 58, the force that can be transmitted from the output pulley 56 to the drive belt 58 and thus the maximum torque that can be transmitted by the drive belt 58 can be changed.

For a targeted conversion of the road construction machine 10, it can carry a further output pulley 56' in a storage space 57, which, if necessary, can be moved against the in figure 1 active output pulley 56 is replaceable. The further output pulley 56' has a different diameter than the output pulley 56.

The drive belt 58 transmits torque to a drive pulley 62 mounted on the alternator 28 which rotates about a drive pulley axis P62 parallel to the pitch axis Ni. The drive pulley 62 is provided with an in figure 1 gear stage 64, not shown in detail, which transmits torque from the drive pulley 62 to an intermediate pulley 66. Each of the pulleys 62 and 66 is coupled to a gear of the gear stage 64 comprising an even number of meshing gears in pairs, so that when torque is transmitted from the drive pulley 62 to the intermediate pulley 66 a reversal of the direction of rotation takes place. The intermediate pulley 66 therefore rotates in the opposite direction of rotation to the drive pulley 62. The intermediate pulley 66 rotates about an intermediate pulley axis P66 parallel to the pitch axis Ni and thus also to the working axis R.

The idler pulley 66 drives a work belt 68 which encircles a work pulley 70 spaced from the idler pulley 66 . The working belt 68 can be tensioned by a working belt tensioner 72 in the same way as the drive belt 58 can be tensioned by the drive belt tensioner 60. The working belt tensioner 72 has the same construction as the drive belt tensioner 60.

The work pulley 70 rotates about a work pulley axis P70 coaxial with the work axis R. The working pulley 70 is rigidly connected to the groove cutting roller 32 via a working shaft arrangement 74 formed by a single working shaft 73 in the example shown and transmits the torque obtained from the intermediate pulley 66 directly and immediately in the same direction to the groove cutting roller 32. The Working shaft 73 and thus the working shaft arrangement 74 pass through the side wall 30d of the housing 30. The shaft connections of the intermediate pulley 66 and the drive pulley 62 with their respective gear wheels of the gear transmission stage 64 also pass through the side wall 30d of the housing 30.

The toothed gear stage 64, the intermediate pulley 66, the working pulley 70 and the working belt 68 form a transmission gear 76 which transmits torque from the drive pulley 62 to the groove cutting roller 32, reversing the direction of rotation. The drive pulley 62 and the grooving roller 32 therefore rotate in opposite directions.

In figure 2 the toothed wheel gear stage 64 is shown, with one pointing to the side wall 30d of the housing 30 and this directly in the fully assembled state opposite front wall of the gear housing 78 is omitted to show the gears of the gear transmission stage 64 in more detail.

The gear housing 78 has a circumferential mounting flange 78a with a plurality of mounting holes 78b, which are penetrated by screws, not shown, to the gear housing 78, which completely encloses the gearwheel gear stage 64, at the point viewed by the viewer figure 1 facing away from the inside of the housing side wall 30d to attach. In the figure 2 The recognizable rear wall 78c is ribbed in a manner known per se to increase its rigidity.

The pulley axes P62 and P66 are orthogonal to the plane of the drawing figure 2 . Pulley shafts rotating about the respective pulley axes can be seen, namely the drive pulley shaft 80 non-rotatably connected to the drive pulley 62 and the intermediate pulley shaft 82 non-rotatably connected to the intermediate pulley 66.

The drive pulley shaft 80 passes through a drive gear 84 and is positively coupled to the drive gear 84 by two springs 86 for common rotation. In the same way, the intermediate pulley shaft 82 is non-rotatably connected to the intermediate gear 88 through which it passes.

The drive gear 84 meshes with a first mediator gear 87 which in turn meshes with a second mediator gear 89 which in turn meshes with the intermediate gear 88 . The gears 84, 87, 89 and 88 form a gear train for transmitting torque between the drive pulley 62 and the intermediate pulley 66. If the drive gear 84 and the intermediate gear 88 are made sufficiently large, they could also mesh directly with one another , where at the in figure 2 shown center distance between the pulley axes P62 and P66, the volume enclosed by the transmission housing 78 would then have to be larger.

The entire gear stage 64 has a speed transmission ratio of between 0.9 and 1.3. Each individual meshing pair of gear wheels of the gear wheel gear stage 64 also has a speed transmission ratio of between 0.9 and 1.3. The specific design of the speed transmission ratio also depends on the selection of the diameters of the pulleys 56, 62, 66 and 70 involved in the torque transmission, since the diameter ratios of pulleys that are coupled by a common belt also establish a transmission ratio.

As in figure 2 As indicated in phantom, the intermediate pulley shaft 88 exits through the rear wall 78c of the gear housing 78 and is there, for the viewer of FIG figure 2 covered by the transmission housing 78, connected to a first clutch part of a switchable starting clutch 90. A second clutch part, which can be selectively brought into torque transmission connection with the first clutch part by shifting the starting clutch 90 or which can be separated from it, is connected to a starting motor 92 . The starter motor 92 can be an electric motor or a hydraulic motor. It is preferably supplied with energy from an energy source on the machine frame side. This energy supply connection is made when connecting the changing unit 28 to the machine frame 12 and is separated again when the changing unit 28 is released from the machine frame 12 .

The starting motor 92 can be used to accelerate the groove cutting roller 32, which is coupled to the intermediate pulley shaft 82 and the intermediate pulley 66 carried by it, from a standstill or from a low initial speed to a first limit speed, from where the motor 52 of the road construction machine 10 takes over the further acceleration up to the predetermined removal speed. The drive belt tensioner 60 can be used together with the drive belt 58 by shifting and subsequently changing the tension of the drive belt 58 as a slip clutch when the drive function is transferred from the starting motor 92 to the main motor 52 .

Likewise, the start-up motor 92 can be used as a rotational resistance when the groove-cutting roller 32 is braked, for example by the groove-cutting roller 32 driving the start-up motor 92 as a generator via the working belt 68 and the intermediate belt pulley 66 in the case of an electric motor as the start-up motor 92 or in the case of a Hydraulic motor drives as a starting motor 92 as a hydraulic pump.

In figure 3 the changing unit 28 is shown in a perspective view. One can see a roller shell 94 surrounding the groove-cutting roller 32 with a small radial distance, which is formed in the lower area of the housing 30 and which has the working opening 30c. An end strip 96 with an elastic lip towards the soil surface A closes the working opening 30c as tightly as possible with the soil surface A, so that dirt exposure to the outside of the exchange unit 28 during soil processing by the groove cutting roller 32 is as low as possible.

A region 30e of the housing 30 located above the roller shell 94 and extending to the connecting section 30a is protected by the roller shell 94 from the dirt generated and whirled up by the groove cutting roller 32 and can therefore be used as a cavity for accommodating, for example, the gear stage 64, the switchable starting clutch 90 and the starting motor 92 are used. A longitudinal wall 30f orthogonal to the working axis R in the area 30e can be used, for example, to fasten the starting motor 92 . The front wall of the transmission housing 78 can therefore be formed by the side wall 30d of the housing 30. FIG.

The working belt tensioner 72 has a tensioning roller 72a and a piston-cylinder arrangement 72b as an actuator for displacing the tensioning roller 72a, the tensioning roller 72a and the piston-cylinder arrangement 72b being coupled by a lever mechanism 72c.

Claims (18)

1. An interchangeable unit (28) for material-removing work on a ground (U) starting from ground surface (A), the interchangeable unit (28) being designed for operational physical and functional coupling to a machine frame (12) of a road construction machine (10), the interchangeable unit (28) comprising:

   - a housing (30), the housing (30) having, in a connecting section (30a) for physically coupling the interchangeable unit (28) to the road construction machine (10), connecting configurations (42) for connecting the interchangeable unit (28) to a machine frame (12) of a road construction machine (10), and the housing (30) having a working opening (30c) in a working section (30b) situated remotely from the connecting section (30a).

   - a removal tool (32), which is mounted on the housing (30) so as to be rotatable about a working axis (R) and of which a circumferential section protrudes from the working opening (30c),

   - a drive belt pulley (62), which is rotatably mounted on the housing (30) and is able to be coupled to a drive belt (58) for functionally coupling the interchangeable unit (28) to the road construction machine (10),

   - a transmission gear unit (76), which transmits torque and rotary motion from the drive belt pulley (62) to the removal tool (32) by reversing the direction of rotation, at least the axis of rotation (P62) of the drive belt pulley (62) running at a distance from the working axis (R).

   characterized in that a working shaft assemblage (74) penetrates a housing wall (30d) of the housing (30), the working shaft assemblage (74) connecting the removal tool (32) with a working gear component (70) situated on the side of the housing wall (30d) facing away from the removal tool (32) for equidirectional joint rotation, the transmission gear unit (76) being situated between the drive belt pulley (62) and the working gear component (70).
2. The interchangeable unit (28) as recited in Claim 1,
   characterized in that the working gear component (70) is a working belt pulley (70).
3. The interchangeable unit (28) as recited in Claim 2,
   characterized in that the transmission gear unit (76) comprises an intermediate belt pulley (66), a first coupling device (64) and a working belt (68) as a second coupling device, the first coupling device (64) coupling the drive belt pulley (62) and the intermediate belt pulley (66) to one another in torque-transmitting fashion and the working belt (68) coupling the intermediate belt pulley (66) and the working belt pulley (70) to one another in torque-transmitting fashion.
4. The interchangeable unit (28) as recited in Claim 3,
   characterized in that the transmission gear unit (76) comprises as the first coupling device (64) a gear wheel transmission stage (64) having at least two meshing gear wheels (84, 87, 89, 88).
5. The interchangeable unit (28) as recited in Claim 4,
   characterized in that the gear wheel transmission stage (64) is situated entirely radially - with respect to the working axis (R) - outside of the radial extension area of the removal tool (32).
6. The interchangeable unit (28) as recited in Claim 4 or 5,
   characterized in that the gear wheel transmission stage (64) is situated axially - with respect to the working axis (R) - overlapping with the axial extension area of the removal tool (32).
7. The interchangeable unit (28) as recited in one of Claims 4 through 6,
   characterized in that the gear wheel transmission stage (64) is accommodated in a transmission stage housing (78), at least one wall of the transmission stage housing (78) also being a wall of the housing (30) of the interchangeable unit (28).
8. The interchangeable unit (28) as recited in one of Claims 4 through 7,
   characterized in that the gear wheel transmission stage (64) comprises exactly four intermeshing gear wheels, one of which is connected to the drive belt pulley (62) for rotation in the same direction and at the same speed and the other of which is connected to the intermediate belt pulley (66) for rotation in the same direction and at the same speed.
9. The interchangeable unit (28) as recited in one of Claims 4 through 8,
   characterized in that the gear wheel transmission stage (64) has a speed transmission ratio of between 0.3 and 5, preferably of between 0.75 and 1.5, particularly preferably of between 0.9 and 1.3.
10. The interchangeable unit (28) as recited in one of the preceding claims,
    characterized in that the removal tool (32) in normal operation has a cutting speed of between 20 and 80 ms^-1, preferably of between 29 and 62 ms^-1.
11. The interchangeable unit (28) as recited in one of the preceding claims,
    characterized in that the removal tool (32) is a cutting drum (32) for grooving work on ground surfaces (A).
12. The interchangeable unit (28) as recited in one of the preceding claims,
    characterized in that it comprises a start-up motor (92), which is separably connected in torque-transmitting fashion to the removal tool (32) via the interpolation of a start-up clutch (90).
13. The interchangeable unit (28) as recited in Claim 12, with the inclusion of Claim 3,
    characterized in that the start-up motor (92) is connected to the drive belt pulley (62) or to the intermediate belt pulley (66) directly in torque-transmitting fashion.
14. A self-propelled road construction machine (10), comprising:

    - a machine frame (12),

    - a traveling gear (22) having at least three drive units (18, 20), which stand in rollable fashion on a subsoil (U),

    - a motor (52) having an output shaft (53) that provides torque,

    - an output belt pulley (56) drivable by the motor (52),

    - connecting counterpart configurations (48) for connecting the machine frame (12) to an interchangeable unit (28) as recited in one of the preceding claims,

    - an interchangeable unit (28), as recited in one of the preceding claims, the interchangeable unit (28) being releasably connected to the machine frame (12) by way of its connecting configurations (42) and the connecting counterpart configurations (48) of the machine frame (12), and

    - a drive belt (58), which connects the output belt pulley (56) to the drive belt pulley (62) in torque-transmitting fashion.
15. Self-propelled road construction machine (10) as recited in Claim 14,
    characterized in that a gear (54), in particular a pump transfer gear (54), is situated between the motor (52) and the output belt pulley (54).
16. Self-propelled road construction machine (10) as recited in Claim 14 or 15,
    characterized in that the road construction machine (10) comprises at least two output belt pulleys (56, 56') of different diameters, which are interchangeable.
17. Self-propelled road construction machine (10) as recited in one of Claims 14 through 16,
    characterized in that the road construction machine (10) further has a displaceable drive belt tensioner (60), the displacement of which is able to modify the tension of the drive belt (58).
18. Self-propelled road construction machine (10) as recited in Claim 17,
    characterized in that the road construction machine (10) comprises an interchangeable unit (28) as recited in one of Claims 12 or 13, the start-up motor and the start-up clutch (90) connecting the start-up motor (92) with the removal tool (32) being controllable by a control device (27) of the road construction machine (10), the road construction machine (10) being designed to carry out the following method for accelerating or for decelerating the rotation of the removal tool (32):

    - switching the start-up clutch (90) into a and/or holding the start-up clutch (90) in a torque-transmitting connection state if the removal tool (32) rotates at a speed that is lower than or equal to a first limit speed, the first limit speed being lower than the removal speed of the removal tool (32) in normal removal operation,

    - switching the drive belt tensioner (60) into a and/or holding the drive belt tensioner (60) in an operating state, which effects an idling tension of the drive belt, which is lower than the operating tension of the drive belt (58) in normal removal operation of the removal tool (32), if the removal tool (32) rotates at a speed that is lower than a second limit speed, the second limit speed being lower than or equal to the first limit speed,

    - changing the tension of the drive belt (58) between the idling tension and a belt tension that is closer to the operating tension in the same direction as the speed of the removal tool (32) between the second limit speed and the removal speed.

Images