EP4029991B1 - Tamper stroke adjustment - Google Patents

Description

The present invention relates to a road finisher according to claim 1 and a method for stepless tamper stroke adjustment on a road finisher according to claim 15.

EP 3 138 961 B1 discloses a road finisher whose screed has a tamper stroke adjustment device. The tamper stroke adjustment device has an adjustment gear that is provided between an eccentric shaft that can be driven in rotation and an eccentric bushing that is rotatably mounted on the eccentric shaft. The stroke of the tamper bar is adjusted by twisting the eccentric bushing on the eccentric shaft. EP 3 138 961 B1 also discloses an adjustment gear that is provided between the rotationally drivable eccentric shaft and an eccentric bushing mounted in a rotationally fixed manner on the eccentric shaft, the eccentric bushing being displaced transversely to the eccentric shaft via the adjustment gear in order to adjust the tamper stroke of the tamper strip. Finally revealed EP 3 138 961 B1 a variator having a toggle mechanism.

In the first two solutions mentioned above, adjusting the eccentric stroke during operation of the road finisher represents a technical challenge. This is due in particular to the fact that it is difficult to control or operate the adjusting gear mounted directly on the eccentric shaft, between the eccentric bushing and the eccentric shaft. The toggle lever mechanism is structurally rather complex and takes up a lot of space on the screed.

US 8,371,770 B1 discloses a screed with a tamper stroke adjustment device, which has a threaded rod and a threaded bushing mounted displaceably thereon. An axial adjustment of the threaded bushing along the threaded rod moves a lever arm mounted on the threaded bushing, the position and alignment of which is dependent on the tamper stroke setting on the screed of the road finisher.

EP 1 905 899 A2 discloses a screed for a road finisher, on which a tamper stroke adjustment device is mounted. The tamper stroke adjustment device comprises a bearing block for an eccentric shaft, which is mounted so that it can be displaced horizontally along a guide carriage and on which an eccentric bushing is mounted in a rotationally fixed manner. By horizontally shifting the bearing block, a distance between the eccentric shaft mounted on it and a tilting axis provided on the screed can be set manually, as a result of which the tamper stroke is set.

EP 2 599 918 A1 discloses a method and a device for adjusting an upper reversal point of a tamper bar of a road finisher. EP 2 599 919 A1 discloses another device for adjusting the stroke of a tamper bar of a road finisher.

The object of the invention is to provide a road finisher with a tamper stroke adjustment device and a method for stepless tamper stroke adjustment on a road finisher, whereby the tamper stroke can be adjusted precisely and steplessly, especially during paving operation, using simple constructive technical means, in particular using fewer assemblies of the road finisher.

This object is achieved using a road finisher according to claim 1 or by means of a method according to claim 15. Advantageous developments of the invention are specified by the respective dependent claims.

The invention relates to a road finisher with a screed for producing a paving layer, wherein the screed has at least one compacting unit for pre-compacting a paving material fed to the screed, and wherein the compacting unit has at least one eccentric bushing, which is rotatably mounted to a desired angle of rotation on an eccentric shaft carrying it , in order thereby to steplessly set a desired tamper stroke of a tamper strip of the compression unit.

According to the invention, in order to rotate the eccentric bushing relative to the eccentric shaft, an adjustment mechanism that is mounted at a distance from the eccentric shaft and rotates at least partially with a rotational movement of the eccentric shaft can be controlled. Since in the case of the invention, despite its spaced position from the eccentric shaft, a self-rotating adjustment mechanism controls the eccentric bushing rotating along with the eccentric shaft for a tamper stroke adjustment, there are several advantages in total, as described below.

Turning the eccentric bushing on the eccentric shaft, i.e. the respective eccentricities of these two components, leads to a phase adjustment, with which the target tamper stroke on the screed can be set. The phase adjustment is advantageously controllable, in particular with little effort, by means of the adjusting mechanism which is spaced apart from the eccentric shaft and primarily rotates with the speed of the eccentric shaft itself. To set the phase adjustment between the eccentric bushing and the eccentric shaft, the co-rotating adjustment mechanism can be controlled at least briefly in such a way that the torque driving it on its input side or the speed present there on its output side, on which it provides a coupling to the eccentric bushing, is exceeded or exceeded is stocky.

As a result, the eccentric bushing coupled to the adjusting mechanism and rotating on the eccentric shaft can be "braked" or "accelerated" relative to the rotational movement of the eccentric shaft according to the transmission ratio controlled by the adjusting mechanism, whereby the eccentric bushing rotates relative to the eccentric shaft into a new angular position, i.e. the the phase adjustment controlled by the adjustment mechanism. Without a separate control of the co-rotating adjustment mechanism, the eccentric bush rotates at the same speed as the eccentric shaft, i.e. together with it with a constant phase angle.

The term "co-rotating" means that the adjustment mechanism or at least a portion of the components provided thereon rotates together with the eccentric shaft, although mounted at a distance from it, during operation of the compression unit. This assembly rotating with the eccentric shaft can be sensitively controlled with little effort for the phase adjustment described above, i.e. a change in the angular position of the eccentric bushing positioned on the eccentric shaft, i.e. to vary the tamper stroke. In addition, the adjustment mechanism positioned at a distance from the eccentric shaft can be controlled more precisely. Furthermore, the tamper stroke adjustment can be carried out better automatically using such a co-rotating adjustment mechanism.

In particular, it can be provided that for the relative rotation of the eccentric bushing to the eccentric shaft, there is a flow of force that is branched off from the eccentric shaft itself to the adjustment mechanism and sets it at least partially in rotation as a function of a rotary movement of the eccentric shaft, the adjustment mechanism set in rotation thereby being controllable in this way that he manipulates the power flow directed to him between his input and his output in such a way that a phase shift occurs at his output, based on which the eccentric bushing on the eccentric shaft is twisted accordingly. The adjustment mechanism can be in the form of a hydraulic and/or electromechanical phase adjustment system, for example.

In the case of the invention, the desired tamper stroke adjustment preferably comes about as the sum of the individual eccentricities of the eccentric shaft and the eccentric bushing mounted so as to be rotatable thereon. A phase angle set in between can be changed in a fast-reacting and very precise manner by means of the co-rotating adjustment mechanism, in particular if this is designed as an electromechanical phase adjuster. As a rotating assembly, the adjustment mechanism can be excellently controlled for a phase adjustment between its drive and its driven side.

As such, the adjustment mechanism used in the invention advantageously builds on existing components or assemblies of the screed in a compact manner, so that a large number of identical parts is possible even on different screed types. Due to its location at a distance from the eccentric shaft, the eccentric shaft itself can be of simpler construction.

Due to the fact that in the invention the adjusting mechanism can preferably be driven in rotation at least partially by the eccentric shaft, there is an overall advantageous balance of forces for adjusting the tamper stroke for the phase adjustment that can be adjusted on it. This in turn means that the adjustment mechanism can be automated more easily, which means that a better paving result is possible using the road finisher.

Preferably, the adjustment mechanism comprises at least one adjustment drive driven in rotation by the rotational movement of the eccentric shaft as such and controllable to rotate the eccentric bushing and/or at least one adjustment gear drive driven in rotation by the rotational movement of the eccentric shaft and controllable to rotate the eccentric bushing. In this embodiment, the rotational movement of the eccentric shaft is generally the cause of the rotation of the adjusting drive and/or the adjusting gear. In this variant, the adjusting drive and/or the adjusting gear is integrated into a drive train branched off from the eccentric shaft, in the power flow of which the adjusting drive and/or the adjusting gear is integrated in a rotating manner. A sensitive variation of the angle of rotation between the eccentric bushing and the eccentric shaft is achieved here by actuating the adjusting drive and/or the adjusting gear with little effort. In particular, the phase shift angle of the adjusting drive and/or adjusting gear rotating along in the power flow can be set more easily as a result. The adjusting mechanism is thus better able to turn the eccentric bushing relative to the eccentric shaft to any desired tamper stroke setting during ongoing paving operation, i.e. to set the tamper stroke between a minimum and a maximum tamper stroke value.

For a compact design, it is advantageous if the adjusting drive and the adjusting gear jointly form a co-rotating functional unit. The functional unit is then in the form of a modular phase adjuster, which is mounted to rotate with the eccentric shaft at the same speed as the eccentric shaft, with the adjusting drive being able to control the adjusting gear for a desired phase adjustment, so that the eccentric bushing rotates in response to the eccentric shaft to vary the tamper stroke.

As described above, in the invention the rotating eccentric shaft can function as an actuator for the co-rotating adjusting drive coupled to it and/or the co-rotating adjusting gear, with the co-rotating adjusting drive and/or the co-rotating Adjusting gear as such is also controlled in addition to their rotation. The torque picked off by the eccentric shaft can be changed at least briefly in the drive train branched off from the eccentric shaft by means of the adjusting drive and/or the adjusting gear rotatably driven therein in order to set the desired phase shift angle, so that the resulting forces decelerate or accelerate the eccentric bushing on the eccentric shaft, i.e. twist it.

Due to the fact that, in the case of the invention, the eccentric shaft is preferably used both to drive the tamper strip and can also be present in the function of a drive shaft for the co-rotating adjustment drive and/or the co-rotating adjustment gear, fulfilling a dual function, so to speak, an adjusting force, possibly acting from the outside the adjusting drive and/or the adjusting gear for turning the eccentric bushing can be significantly reduced. As a result, the components used for adjusting the tamper stroke can also be structurally reduced, with the result that manufacturing costs can be reduced.

The torque, which is preferably continuously tapped off from the eccentric shaft during paving operation, can be manipulated in the branched-off power flow using the co-rotating adjustment drive and/or the co-rotating adjusting gear arranged therein in such a way that an adjustment movement of the eccentric bushing on the eccentric shaft rotating by means of the drive speed is possible without any problems and without a large additional force input is. An adjusting torque for varying the tamper stroke, ie for changing a vectorial sum of the individual eccentricities of the eccentric bushing and the eccentric shaft, results from the phase adjustment that can be controlled by means of the adjusting drive and/or the adjusting gear. While the phase adjustment is being carried out, the eccentric bushing is rotated relative to the rotational movement of the eccentric shaft in or counter to a direction of rotation of the eccentric shaft until the eccentric bushing assumes a desired angular position on the eccentric shaft that is shifted from its starting position.

The co-rotating adjusting drive and/or the co-rotating adjusting gear can preferably be controlled to adjust a rotation angle of a machine element rotatably mounted on the eccentric shaft. The machine element enables the adjustment drive and/or the adjustment gear to be coupled in a structurally simple manner to the eccentric shaft mounted eccentric bush. The machine element can for example be in the form of a toothed wheel or a pulley for a synchronous belt.

One embodiment provides that the machine element itself forms the eccentric bushing or is connected to the eccentric bushing by means of a positive coupling, for example by means of a claw coupling. The former alternative results in an assembly with a reduced part count. The second alternative can be advantageous for service and/or repair measures.

For a standardized structure, it is advantageous if at least one additional machine element is provided, which is designed to transmit a rotary motion of the eccentric shaft to the adjusting drive and/or the adjusting gear. The further machine element is preferably mounted in a rotationally fixed manner on the eccentric shaft. This is preferably a toothed wheel or a pulley for a synchronous belt. For the other machine element, a complementary coupling element, for example in the form of a gear wheel or a belt pulley for the synchronous belt, can be mounted non-rotatably on the adjustment drive and/or on the adjustment gear, for example on a gear housing of the adjustment gear or on a housing of the adjustment drive.

The motion or forces can be transmitted from the eccentric shaft to the adjustment mechanism by means of the additional machine element. A separate, e.g. hydraulic or electromechanical control of the adjusting mechanism set in rotation, in particular of the adjusting drive that rotates along with it and/or the adjusting gear that rotates along with it, causes the first machine element, which is coupled to its output side and is rotatably arranged on the eccentric shaft - and thus also the eccentric bushing - to be phase-adjusted becomes. As soon as the first machine element has assumed the desired angular position, ie the target tamper stroke has been set, the aforementioned separate activation of the rotary-driven adjustment mechanism is terminated. An actual angle of rotation between the eccentric bushing and the eccentric shaft that is thus set on the compression unit can then be easily detected by means of suitable sensors. The adjustment mechanism, which rotates continuously during the operation of the compression unit, can be controlled again for a subsequently desired phase adjustment, so that a new switching moment occurs on its output side coupled to the eccentric bushing compared to its drive side.

The machine elements described above for coupling the eccentric shaft to the adjusting mechanism and for coupling the same to the eccentric bushing can be in the form of gear wheels, belt pulleys and/or sprockets and thus form standardized, primarily cost-effective machine components.

Although this is not absolutely necessary, it makes sense for the adjusting drive and/or the adjusting gear to be driven in rotation at the same speed as the eccentric shaft during operation of the compression unit. For example, gear wheels/chain wheels or belt pulleys of the same dimensions are used for this purpose in the drive train between the eccentric shaft and the adjustment mechanism that is driven in rotation with it. In particular, during operation of the compression unit, the adjusting drive and/or the adjusting gear can have a different speed than the eccentric shaft. A desired tamper stroke can be achieved in that there is the same translation between the eccentric shaft and the adjusting gear and between the adjusting gear and the eccentric bushing. In other words, the eccentric shaft and the adjusting shaft on which the adjusting gear is mounted can have different speeds; the eccentric shaft and the eccentric bushing do not.

It is advantageous if the adjusting drive and/or the adjusting gear can be actuated hydraulically, electrically and/or mechanically. Above all, large adjusting forces could be generated by means of a hydraulic adjusting drive and/or adjusting gear. An electrical or electromechanical adjustment mechanism would allow the tamper stroke to be adjusted with shorter reaction times, i.e. independently of a hydraulic temperature.

The adjusting gear is preferably a continuously adjustable mechanical, hydrostatic or electric gear. The adjusting gear can preferably be controlled to set a desired transmission ratio by means of a mechanical, hydraulic or electric drive that is already present on the screed, i.e. by means of a drive that is also used to operate another working component of the screed. This further contributes to a reduction in the number of components or assemblies used.

A variant provides that the adjusting drive has a controllable servo motor and/or a servo motor is provided for the adjusting gear. The servomotor together with the adjusting gear can form a functional unit rotating with the eccentric shaft, the servomotor being controllable for a desired phase adjustment in such a way that it changes the power flow transmitted to the eccentric bushing via the adjusting mechanism rotating with it through the adjusting gear connected to it. In response, the eccentric bushing rotates on the eccentric shaft to the desired angular position.

The adjusting mechanism is preferably designed as a cam mechanism and/or has a pair of rotating deflection rollers. In this way, the adjustment gear can be designed to be particularly robust. It is conceivable for the cam mechanism to have two cam disks which are mounted so as to be adjustable in relation to one another and can be displaced linearly and/or rotationally in relation to one another. A movement of the cam discs relative to each other can cause the deflection rollers mounted thereon to be adjusted along curved paths formed thereon, which results in a phase adjustment.

According to one embodiment of the invention, the adjustment mechanism provides at least one stationary cam and at least one movably mounted cam for shifting the deflection rollers mounted thereon and rotating in the power flow. This is mounted on the stationary cam disk for translational and/or rotational displacement, in order thereby to set a displacement of the axes of rotation of the deflection rollers that rotate along for a phase adjustment.

According to one embodiment, the pair of rotating deflection rollers for rotating the eccentric bushing is mounted on the eccentric shaft so as to be displaceable transversely to the eccentric shaft, i.e. transversely to its axis of rotation. The co-rotating deflection rollers can be mounted adjacent to a toothed belt or a drive chain, which is connected to the machine element mounted rotatably on the eccentric shaft. By shifting the deflection rollers, the length ratio of the belt or chain sections that are guided opposite one another changes at the same time, so that the machine element on the eccentric shaft rotates in response to this, i.e. the eccentric bushing is phase-shifted in relation to the eccentric shaft.

The two co-rotating deflection rollers can be rotatably mounted with respect to mutually spaced, parallel mounted axes of rotation. A change in the positioning of the co-rotating deflection rollers, in particular a change in the distance between the axes of rotation, can be used to influence the phase adjustment angle, based on which the eccentric bushing lies on the eccentric shaft.

Preferably, a translational displacement of the co-rotating deflection rollers transverse to the axis of rotation of the eccentric shaft on one side of the synchronous belt guided around the deflection rollers or the drive chain leads to a lengthening of the track, which is simultaneously compensated for by a shortening of the track on the opposite side of the synchronous belt or the drive chain. As a result, the eccentric bushing can be rotated on the eccentric shaft with little effort, so that the eccentric bushing assumes a desired angle of rotation on the eccentric shaft for setting the tamper stroke.

An advantageous variant provides that the adjusting drive and/or the adjusting gear is designed for the synchronous adjustment of several eccentric bushings that are rotatably mounted along the eccentric shaft (overall stroke adjustment) or the adjusting mechanism includes several adjusting drives and/or adjusting gears for the separate adjustment of several eccentric bushings that are rotatably mounted along the eccentric shaft ( single stroke adjustment). With these variants, the eccentric bushings installed along several unit sections can be adjusted together, i.e. synchronously with one another, or independently of one another, i.e. individually. Using eccentric bushings that can be controlled independently of one another, different tamper strokes can be set during one paving journey over the paving width that can be created using the screed.

For synchronous adjustment of the eccentric bushes, the adjustment mechanism can be coupled to an adjustment shaft on its output side. The adjustment shaft can transmit a phase adjustment set centrally by means of the adjustment mechanism synchronously to a number of unit sections of the compression unit, i.e. to eccentric bushings mounted thereon. As an alternative to this, there can be an independently controllable, co-rotating adjusting mechanism for each unit section of the compression unit. These can be mounted on a common shaft, via which they each record a rotational movement of the eccentric shaft. However, different phase adjustments can be set on the output side. The adjusting shaft or the shaft is preferably mounted parallel to the eccentric shaft.

According to one embodiment, the adjusting drive and/or the adjusting gear can be controlled by means of a control device in order to set the desired angle of rotation of the eccentric bushing. The control device, regardless of whether it is used for a total stroke adjustment or an individual stroke adjustment, can be present as an integral part of the adjustment mechanism. The control device can be connected via a CAN bus system to a vehicle controller of the road finisher, from which the setpoint tamper stroke or the respective setpoint tamper strokes can be maintained.

A particularly preferred variant provides that the control device for the dynamic adjustment of the angle of rotation of the eccentric bushing has at least one control loop that responds to at least one process parameter that can be detected during operation of the road finisher. On the basis of the control circuit, for example, a measured material-specific value of the paving material to be paved, for example a measured temperature of the paving material transported from the goods bunker of the road finisher to the paving screed, and/or the paving layer produced, for example a measured temperature of the paving layer, be reacted accordingly with an adjustment of the angle of rotation between the eccentric bushing and the eccentric shaft in order to produce an optimal installation result.

A preferred embodiment of the invention provides that the control circuit is able to control a dynamic angle of rotation adjustment between the eccentric bushing and the eccentric shaft in response to a disturbance variable, for example an ambient temperature, for the continuous adjustment of the tamper stroke.

It is conceivable that when adjusting the tamper stroke setting, a set angle of attack of the screed, a paving speed driven by the road finisher, a set drive speed of the eccentric shaft, a temperature of the compactor plates of the screed and/or measured values from a separate construction site vehicle, for example measured values relating to the paving layer produced, which are based on of a compactor vehicle driving behind the road finisher can be taken into account.

The adjustment mechanism preferably includes at least one sensor unit, which is designed to detect a set phase angle between the eccentric bushing and the eccentric shaft that carries it and/or to detect a stroke of the tamper strip. It is conceivable that the adjustment drive, especially when it is in the form of a servo motor, has at least one sensor unit suitable for this purpose, for example one or more angle sensors. This would allow the phase shift between the eccentric bushing and the eccentric shaft to be derived on the basis of the detected angular position of the motor shaft of the servo motor. The control device can calculate the actual tamper stroke based on the detected phase setting. It is conceivable that the control device derives the corresponding actual tamper stroke based on the measured phase setting, for example by means of phase characteristics. A phase setting detected or varying by means of the sensor unit can be transmitted to the control unit in a timely manner, so that based on a target/actual tamper stroke comparison, it may output a corresponding control signal to the adjustment drive, in particular the servo motor, in order to react quickly to rotate the eccentric bushing for a to control tamper stroke adjustment.

According to one embodiment, the sensor unit could have at least one distance sensor, which is designed to directly measure a set actual tamper stroke of the tamper strip.

A practical variant provides that the adjustment mechanism is designed to be manually adjustable. Above all, this can be used to calibrate the tamper strip at the beginning of the paving journey be helpful. Automated operation of the adjustment mechanism, on the other hand, can be used excellently during the paving journey.

The invention also relates to a method for stepless adjustment of the tamper stroke on a compacting unit of a road finisher, with at least one eccentric bush being rotated on an eccentric shaft supporting it in order to adjust the taper stroke. According to the invention, in order to rotate the eccentric bushing on the eccentric shaft, an adjusting mechanism is controlled which is mounted at a distance from the eccentric shaft and rotates at least partially with a rotational movement of the eccentric shaft.

Preferably, the relative rotation between the eccentric bushing and the eccentric shaft is caused by the fact that a flow of force derived from the eccentric shaft, which causes the adjustment mechanism or at least parts of it to rotate, is at least briefly reduced or increased by means of the adjustment mechanism in such a way that the angle of rotation between of the eccentric bushing and the eccentric shaft changed. Here, the torque is derived from the eccentric shaft and transmitted to the adjustment mechanism as drive torque. In particular, an adjustment gear that is connected to it and also rotates along with it can be controlled for torque adjustment by means of an adjustment drive. In this embodiment, the eccentric bush rotates uniformly on the eccentric shaft, i.e. at the same speed, without additional control of the adjustment drive. Using a separate control of the adjusting drive, a differential speed can be generated via the adjusting gear coupled to it between the eccentric bushing and the eccentric shaft supporting it, as a result of which the eccentric bushing rotates into a new angular position on the eccentric shaft. This adjusts the tamper stroke. This means that the compression unit can manage overall with a reduced number of mechanical, electrical and/or hydraulic components in order to vary the tamper stroke. This results in a practical adjustment device that can be produced inexpensively and works essentially autonomously for varying the tamper stroke on the road finisher.

Figur 1

eine schematische Seitenansicht eines Straßenfertigers,

Figur 2

ein Verdichtungsaggregat für eine Einbaubohle eines Straßenfertigers gemäß einer ersten Ausführungsform,

Figur 2A

ein erster Betriebszustand des in Figur 2 gezeigten Verdichtungsaggregats,

Figur 2B

ein zweiter Betriebszustand des in Figur 2 gezeigten Verdichtungsaggregats,

Figur 2C

eine Variante der in Figur 2 gezeigten ersten Ausführungsform für eine Gesamthubverstellung,

Figur 2D

eine Variante der in Figur 2 gezeigten Ausführungsform für eine Einzelhubverstellung,

Figur 3

ein Verdichtungsaggregat für eine Einbaubohle eines Straßenfertigers gemäß einer zweiten Ausführungsform,

Figur 3A

eine Schnittdarstellung des Verstellmechanismus der in Figur 3 gezeigten zweiten Ausführungsform,

Figur 3B

eine gesonderte Darstellung des Verstellmechanismus der in Figur 3 gezeigten Ausführungsform,

Figur 3C

eine Variante der in Figur 3 gezeigten zweiten Ausführungsform für eine Gesamthubverstellung, und

Figur 3D

eine schematische Darstellung der zweiten Ausführungsform aus Figur 3 für eine Einzelhubverstellung.

Advantageous embodiments of the invention are explained in more detail with reference to the following figures. Show it:

figure 1

a schematic side view of a road finisher,

figure 2

a compaction unit for a screed of a road finisher according to a first embodiment,

Figure 2A

a first operating state of the in figure 2 compression unit shown,

Figure 2B

a second operating state of the in figure 2 compression unit shown,

Figure 2C

a variant of the in figure 2 shown first embodiment for a total stroke adjustment,

Figure 2D

a variant of the in figure 2 shown embodiment for a single stroke adjustment,

figure 3

a compaction unit for a screed of a road finisher according to a second embodiment,

Figure 3A

a sectional view of the adjustment mechanism in figure 3 shown second embodiment,

Figure 3B

a separate representation of the adjustment mechanism in figure 3 shown embodiment,

Figure 3C

a variant of the in figure 3 shown second embodiment for a total stroke adjustment, and

Figure 3D

a schematic representation of the second embodiment figure 3 for a single stroke adjustment.

Identical components are provided with the same reference symbols throughout the figures.

figure 1 shows a road finisher 1 with a screed 2 for producing a paving layer 3 in the paving direction of travel R. The screed 2 has at least one compacting unit 4 for pre-compacting paving material 5 fed to the screed 2. The compacting unit 4 has a tamper strip 6, which has a variable tamper stroke H and/or a variable frequency F for pre-compacting the paving material 5 fed to the screed 2.

figure 2 shows the compression unit 4 separately in an enlarged perspective view. The compression unit 4 has a bearing block 7 fastened to the screed body and an eccentric shaft 8 rotatably mounted thereon. The eccentric shaft 8 drives a connecting rod 9 to which the tamper bar 6 is fastened.

figure 2 also shows an adjusting mechanism 10 which is driven in rotation by means of the eccentric shaft 8 . The adjusting mechanism 10 can be controlled to set a target tamper stroke 11 that can be varied for the tamper strip 6 . For this purpose, the co-rotating adjustment mechanism 10 includes an adjustment drive 12 and/or an adjustment gear 13. According to FIG figure 2 the adjusting drive 12 and the adjusting gear 13 are designed as a functional unit. This functional unit is coupled to a rotary motion of the eccentric shaft 8 by means of a timing belt 14 .

The adjustment mechanism 10 can, without being additionally controlled, return the torque driving it by means of the synchronous belt 14 on its input side and setting it into rotation to a machine element 16 rotatably mounted on the eccentric shaft 8 by means of a further synchronous belt 15 provided on its output side. A phase angle of the machine element 16 mounted on the eccentric shaft 8 can be changed by an additional activation of the adjustment mechanism 10 . On the basis of this phase adjustment, an eccentric bushing 17 (see Fig Figure 2C ) adjust. According to figure 2 is thus for rotating the eccentric bushing 17 on the eccentric shaft 8 of the eccentric shaft 8 mounted spaced, with the rotational movement of the eccentric shaft 8 co-rotating adjustment mechanism 10 can be controlled.

Based on Figures 2A and 2B the implementation of a phase adjustment by means of the adjustment mechanism 10 is shown schematically in order to adjust the tamper stroke 11 .

In Figure 2A the synchronous belt 14, which is guided over a pulley 18 mounted in a torque-proof manner on the eccentric shaft 8, transmits the rotational movement of the eccentric shaft 8 to a housing 19 of the adjusting mechanism 10. The housing 19 can be designed with a diameter like the pulley 18. A belt drive is thus produced between the eccentric shaft 8 and the adjustment mechanism 10 which ensures that the adjustment mechanism 10 rotates at the speed of the eccentric shaft 8 .

In Figure 2A the co-rotating adjusting mechanism 10 is not additionally controlled, so that a torque applied to its housing 19 on its input side is passed on to the machine element 16 via the further synchronous belt 15 fastened on its output side. This has according to Figure 2A As a result, the eccentric bushing 17 mounted within the connecting rod 9 rotates at the speed of the eccentric shaft 8, ie it maintains its angular position relative to the eccentric shaft 8. Figure 2A shows this situation schematically using the two markings A, B running in the same direction.

In Figure 2B has the adjustment mechanism 10 opposite Figure 2A a phase adjustment 26 performed. This is shown on the basis of the two markings A, B that are now shown shifted relative to one another. In response to this, the machine element 16 has moved in relation to the Figure 2A shown position on the eccentric shaft 8 according to the phase adjustment 26 rotated. This has the effect that the eccentric bushing 17 coupled to the machine element 16 also assumes an angular position on the eccentric shaft 8 that has been changed by the phase adjustment 26 , so that the sum of the eccentricity of the eccentric shaft 8 results in a new target tamper stroke 11 .

Figure 2C shows a first variant of the in figure 2 embodiment shown for a total stroke adjustment on the compression unit 4. This means that a plurality of eccentric bushings 17 positioned along the eccentric shaft 8 can be rotated synchronously by means of the adjustment mechanism 10.

In Figure 2C the eccentric shaft 8 is driven by a motor 20. The one in the figure 2 Belt drives shown for coupling the eccentric shaft 8 to the adjustment mechanism 10 and for coupling the adjustment mechanism 10 to the machine element 16 are in the Figures 2C and 2D replaced by drive wheels 21, 22 and adjusting wheels 23, 24. The drive wheel 21 is mounted on the eccentric shaft 8 in a torque-proof manner. The drive wheel 22 is seated on the housing 19 of the adjustment mechanism 10 in a rotationally fixed manner. The adjustment mechanism 10 is mounted on a shaft 25 in a rotationally fixed manner. The adjustment mechanism 10 is configured to carry out the phase adjustment 26 between the drive wheel 22 mounted on its housing 19 and the adjustment wheel 23 mounted on its wear side. The phase adjustment 26 carried out by means of the adjustment mechanism 10 is transmitted from the adjustment wheel 23 to the adjustment wheel 24 and the machine element 16 . According to Figure 2C the adjusting wheel 24 and the machine element 16 are formed in one piece. By twisting the machine element 16, the in Figure 2C rotated by means of a claw coupling 27 connected thereto eccentric bushing 17 on the eccentric shaft 18. This results in a change in the (desired) tamper stroke 11 of the tamper bar 6 .

In Figure 2C the adjustment mechanism 10 has a sensor unit 28 which is configured to detect the phase adjustment 26 and thus also the angular position of the eccentric bushing 17 on the eccentric shaft 8 . The sensor unit 28 continuously transmits its measurement results to a control device 29 connected to it. The control device 29 can be provided with the setpoint tamper stroke 11, with the control device 29 being configured to calculate an actual tamper stroke from the measured phase adjustment 26 and to compare this with the provided To compare target tamper stroke 11, based on which the control device 29 sends a control signal 30 to the Adjustment drive 12 of the adjustment mechanism 10 emits. The adjustment drive 12, for example a co-rotating synchronous motor M, can then adjust the phase adjustment 26 based on the control signal 20.

The control device 29 can have a control circuit RK, which responds to a process parameter P measured during operation of the road finisher 1, on the basis of which a dynamic angle of rotation adjustment, ie a dynamic phase adjustment 26 for varying the tamper stroke 11, is possible. The functional principle of the control device 29 and/or the control circuit RK can also be used in connection with all of the following embodiments.

Figure 2C FIG. 12 further shows that the adjustment mechanism 10 has an adjustment shaft 31 on its output side. According to Figure 2C the adjustment wheel 23 is mounted on the adjustment shaft 31 in a rotationally fixed manner. This makes it possible to Figure 2C to transmit the phase adjustment 26 set by means of the adjustment mechanism 10 synchronously to another unit section 32 via the adjustment shaft 31 . There, by means of further adjustment wheels 33, 34, an eccentric bushing, which is not shown on the unit section 32, is rotated synchronously with the eccentric bushing 17 in an analogous manner.

Figure 2C thus shows that the adjustment mechanism 10 is designed via the adjustment shaft 31 for the synchronous adjustment of a plurality of eccentric bushings 17 that are rotatably mounted along the eccentric shaft 8 .

Figure 2D 12 shows a device which is designed for the separate adjustment of a plurality of eccentric bushings 17 which are rotatably mounted along the eccentric shaft 8 . A single stroke adjustment is thus possible by means of this device.

According to Figure 2D the compression unit 4 includes the adjustment mechanism 10 for varying the target tamper stroke 11 of the tamper strip 6 and also an additional adjustment mechanism 10' for the further unit section 32. The adjustment mechanism 10' is driven via the shaft 25 and has a sensor unit 28', by means of which a phase adjustment 26' set on the unit section 32 can be measured, on the basis of which the eccentric bushing 17' mounted on the unit section 32 is rotated on the eccentric shaft 8. For independent actuation of the two adjusting wheels 23, 33, they are rotatably mounted on the shaft 25. This makes it possible to set the desired tamper stroke 11, 11' for the respective tamper strips 6, 6' on the respective unit sections of the compression unit 4 independently of one another.

figure 3 shows a second embodiment of the compression unit 4. The compression unit 4 has an adjustment mechanism 35. The adjustment mechanism 35 can be controlled to rotate the machine element 16, which is rotatably mounted on the eccentric shaft 8, in such a way that the target tamper stroke 11 is set on the tamper bar 6 leaves.

The adjustment mechanism 35 off figure 3 has a pair of co-rotating deflection rollers 36a, 36b. The two deflection rollers 36a, 36b are mounted so as to be displaceable back and forth transversely to the eccentric shaft 8, as shown by the double arrows v1, v2. The adjustment mechanism 35 is connected to the rotational movement of the eccentric shaft 8 by means of drive pulleys 37, 38, 39 mounted in a rotationally fixed manner by means of synchronous belts 40, 41 guided thereon. In the figure 3 Drive pulleys 38, 39 shown separately could also be designed as one component. A displacement of the two deflection rollers 36a, 36b transversely to the eccentric shaft 8 causes the machine element 16, which is connected to the adjustment mechanism 35 via the synchronous belt 41, to rotate on the eccentric shaft 8. The eccentric bushing 17 attached thereto also changes its angular position on the eccentric shaft 8 as a result, so that the (set) tamper stroke 11 is adjusted.

The functional principle of the phase adjustment using the adjustment mechanism 35 is in Figure 3A shown in more detail. In the left half of the picture Figure 3A the drive pulley 39 and the machine element 16 are both mounted at the angle of rotation φ. For this, the adjusting mechanism 35 assumes a corresponding position according to FIG Figure 3A a. This positioning of the two co-rotating deflection rollers 36a, 36b results in a minimal tamper lift 11 for the tamper bar 6.

In the right half of the picture Figure 3A the setting of the adjusting mechanism 35 for a maximum tamper stroke 11 of the tamper strip 6 is shown. In response to a shift R1 , R1 ' , R2 , R2 ' of the two deflection rollers 36a, 36b, a new angle of rotation φ′ has resulted for the machine element 16 . The displacement of the two co-rotating deflection rollers 36a, 36b transversely to the eccentric shaft 8 driving them thus causes the phase adjustment 26 of the machine element 16, as a result of which the eccentric bushing 17 on the eccentric shaft 8 rotates.

Figure 3B shows a potential structure for the adjustment mechanism 35. The adjustment mechanism 35 has an adjustably mounted cam 42 with a first cam track 43 for the deflection roller 36a and with a second cam track 44 for the deflection roller 36b. Furthermore, the adjustment mechanism 35 has a stationary cam 45 with a guide track 46 for the deflection rollers 36a, 36b. The two deflection rollers 36a, 36b in the guide track 46 are moved together in the direction F by means of a displacement of the cam disk 42 in direction E. By shifting the two deflection rollers 36a, 36b, the phase adjustment 26 takes place on the machine element 16, as a result of which the eccentric bushing 17 rotates on the eccentric shaft 8.

Next shows Figure 3B in the right half of the picture a section AA. The deflection roller 36a is mounted on a bolt 47 . To reduce frictional resistance, the deflection roller 36a is attached to the bolt 47 by means of a roller bearing 48 .

The Figures 3C and 3D show variants of the adjustment mechanism 35, with the in Figure 3C Variant shown for the synchronous adjustment of a plurality of eccentric bushings 17 rotatably mounted along the eccentric shaft 8 (overall stroke adjustment) and wherein the in Figure 3D shown variant are configured for a single stroke adjustment on respective adjacent unit sections of the compression unit 4.

In Figure 3C the adjustment mechanism 35 is mounted between the drive wheel 37 and an adjustment wheel 50 . A using the adjustment mechanism 35 in Figure 3C set phase adjustment 26 acts via the timing belt 40 on the adjusting wheel 50, wherein the adjusting wheel 50 carrying the adjusting shaft 31 'can transmit the torque synchronously to other unit sections of the compression unit 4 to eccentric bushings stored there corresponding to the eccentric bushing 17 Figure 3C set.

In Figure 3C the phase adjustment 26 set by means of the adjustment mechanism 35 is transmitted via the two adjustment wheels 50, 51 and the timing belt 41 to the machine element 16, which occupies a corresponding angle of rotation φ on the eccentric shaft 8. The machine element 16 is connected to the eccentric bushing 17 via the claw coupling 27 . The phase adjustment 26 set on the machine element 16 is thus transmitted to the eccentric bushing 17, on the basis of which the target tamper stroke 11 can be set.

The schematic diagram Figure 3D shows that the adjustment mechanism 35 according to figure 3 is arranged, so between the drive wheel 39 and the machine element 16, the phase adjustment 26 can generate. According to Figure 3D a separate adjustment mechanism 35 can be arranged for each unit section of the compression unit 4, so that the respective tamper strokes 11 of the unit sections can be controlled independently of one another.

Claims (15)

1. Road finishing machine (1) with a screed (2) for producing a paving layer (3), wherein the screed (2) includes at least one compacting unit (4) for precompacting paving material (5) supplied to the screed (2), wherein the compacting unit (4) includes at least one eccentric bushing (17) mounted on an eccentric shaft (8) supporting the same to be rotatable to a desired angle of rotation to thereby continuously variably set a desired tamper stroke of a tamper bar (6) of the compacting unit (4), characterized in that for rotating the eccentric bushing (17) on the eccentric shaft (8), an adjusting mechanism (10, 35) mounted spaced apart from the eccentric shaft (8) and at least partially rotating along with a rotary motion of the eccentric shaft (8) is activatable.
2. Road finishing machine according to claim 1, characterized in that the adjusting mechanism (10, 35) comprises at least one adjusting drive (12) that can be activated for rotating the eccentric bushing (17) and which is rotationally driven by means of the rotary motion of the eccentric shaft (8) as such, and/or at least one adjusting transmission (13) that can be activated for rotating the eccentric bushing (17) and is rotationally driven by means of the rotary motion of the eccentric shaft (8).
3. Road finishing machine according to claim 2, characterized in that the adjusting drive (12) rotating along and/or the adjusting transmission (13) rotating along can be activated to adjust an angle of rotation (ϕ) of a machine element (16) rotatably mounted on the eccentric shaft.
4. Road finishing machine according to claim 3, characterized in that the machine element (16) itself forms the eccentric bushing (17) or is connected to the eccentric bushing (17) by means of a positive clutch (27).
5. Road finishing machine according to one of claims 3 or 4, characterized in that at least one further machine element is provided which is embodied for transmitting a rotary motion of the eccentric shaft (8) to the adjusting drive (12) and/or the adjusting transmission (13).
6. Road finishing machine according to one of claims 2 to 5, characterized in that during an operation of the compacting unit (4), the adjusting drive (12) and/or the adjusting transmission (13) is rotationally driven at the same speed or at a speed different from that of the eccentric shaft (8).
7. Road finishing machine according to one of claims 2 to 6, characterized in that the adjusting drive (12) and/or the adjusting transmission (13) is actuatable hydraulically, electrically and/or mechanically.
8. Road finishing machine according to one of claims 2 to 7, characterized in that the adjusting drive (12) includes an activatable servomotor (M), and/or a servomotor (M) is provided for the adjusting transmission (13).
9. Road finishing machine according to one of claims 2 to 8, characterized in that the adjusting transmission (13) is embodied as a cam mechanism and/or includes a pair of rotating deflection rollers (36a, 36b).
10. Road finishing machine according to claim 9, characterized in that the pair of rotating deflection rollers (36a, 36b) is movably mounted transverse to the eccentric shaft (8) for rotating the eccentric bushing (17) on the eccentric shaft (8).
11. Road finishing machine according to one of claims 2 to 10, characterized in that the adjusting mechanism (10, 35) is embodied for synchronously adjusting a plurality of eccentric bushings (17) rotationally mounted along the eccentric shaft (8), or the adjusting mechanism (10, 35) comprises a plurality of adjusting drives (12) and/or adjusting transmissions (13) for separately adjusting a plurality of eccentric bushings (17) rotationally mounted along the eccentric shaft (8).
12. Road finishing machine according to one of claims 2 to 11, characterized in that the adjusting drive (12) and/or the adjusting transmission (13) is activatable for setting the desired angle of rotation (ϕ) of the eccentric bushing (17) by means of a controlling system (29).
13. Road finishing machine according to claim 12, characterized in that the controlling system (29) includes, for a dynamic adaption of the angle of rotation of the eccentric bushing (17), at least one control loop (RK) responding to at least one process parameter (P) detectable during the operation of the road finishing machine (1).
14. Road finishing machine according to one of claims 2 to 13, characterized in that the adjusting mechanism (10, 35) comprises at least one sensor unit (28) which is embodied for detecting a set angle of rotation (ϕ) of the eccentric bushing (17) on the eccentric shaft (8) supporting the same and/or for detecting a tamper stroke (11) of the tamper bar (6).
15. Method for a continuously variable tamper stroke adjustment at a compacting unit (4) of a road finishing machine (1), wherein for adjusting the tamper stroke (11), at least one eccentric bushing (17) is rotated on an eccentric shaft (8) mounting the same, characterized in that for rotating the eccentric bushing (17) on the eccentric shaft (8), an adjusting mechanism (10, 35) mounted at a distance to the eccentric shaft (8) and at least partially rotating along with a rotary motion of the eccentric shaft (8) is activated.

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