Abstract
A tamping beam device of a paving screed, in particular of a road paver, with a tamping beam, which is arranged on at least one connecting rod, with a drive shaft, which is connected to the connecting rod via an eccentric device. The eccentric device is configured such that a first and a second stroke setting of the tamping beam can be adjusted by means of a thrust member that is axially adjustable on the drive shaft. The thrust member comprises a first region, which is arranged in the eccentric device, and a second region, which is arranged outside the eccentric device. The second region is connected to an axial adjustment device via a thrust bearing. A paving screed and a road paver having such a tamping beam device. A method for changing the stroke of a tamper beam device.
Claims
1. A tamping beam device of a paving screed, in particular of a road paver, with a tamping beam which is arranged on at least one connecting rod, with a drive shaft which is connected to the connecting rod via an eccentric device, wherein the eccentric device is configured such that a first and a second stroke setting of the tamping beam can be set by means of a thrust member which is axially adjustable on the drive shaft, wherein: the thrust member comprises a first region, which is arranged in the eccentric device, and a second region, which is arranged outside the eccentric device, the second region being connected to an axial adjustment device via a thrust bearing.
2. The tamping beam device according to claim 1, wherein the thrust bearing is provided between an adjusting ring mounted on the second region of the thrust member and an actuating element of the axial adjustment device.
3. The tamping beam device according to claim 2, wherein a first end, in particular a head, of the actuating element at least partially engages around the adjusting ring.
4. The tamping beam device according to claim 2, wherein a first bearing and a second bearing are provided between the adjusting ring and the actuating element, in particular wherein the first bearing and the second bearing are arranged opposite each other, preferably diametrically opposite each other, and wherein a contact-free region between the adjusting ring and the actuating element is provided in the circumferential direction between the first bearing and the second bearing.
5. The tamping beam device according to claim 4, wherein the first bearing and the second bearing are plain bearings formed by plain bearing contact surfaces between the adjusting ring and the actuating element.
6. The tamping beam device according to claim 5, wherein at least the plain bearing contact surfaces of the adjusting ring and of the actuating element consist of a plain bearing material, in particular a plain bearing plastic material, in particular wherein the adjusting ring consists entirely of a plain bearing material, in particular a plain bearing plastic material.
7. The tamping beam device according to claim 4, wherein a third bearing is provided between the adjusting ring and the actuating element, which is arranged between the first bearing and the second bearing, in particular wherein the third bearing is a plain bearing.
8. The tamping beam device according to claim 2, wherein the actuating element has one or more, in particular two or three, extensions which engage in a recess, in particular a groove, of the adjusting ring.
9. The tamping beam device according to claim 2, wherein the first bearing and the second bearing are rolling bearings.
10. The tamping beam device according to claim 2, wherein the actuating element is fixed to a rod of the axial adjustment device, wherein the rod runs essentially parallel to the drive shaft.
11. The tamping beam device according to claim 10, wherein a bushing is arranged on the rod, which bushing is connected to a second end of the actuating element.
12. The tamping beam device according to claim 1, wherein the axial adjustment device has a manual or motorized drive, in particular a spindle drive, for axial adjustment.
13. A paving screed for a road paver with a tamping beam device according to claim 1.
14. The paving screed according to claim 13, wherein it comprises a tamping beam which is supported and driven via at least two of the tamping beam devices.
15. A road paver with a paving screed according to claim 13.
16. A method for changing the stroke of a tamping beam device according to claim 1, comprising the steps of: a) operating the tamping beam device with a first stroke setting with a rotating drive shaft; b) adjusting a thrust member on the drive shaft along the rotation axis of the drive shaft via an axial adjustment device, which is connected to the thrust member via a thrust bearing; c) converting the movement of the thrust member along the drive shaft into an adjustment movement of an eccentric ring in radial direction relative to the rotation axis of the drive shaft; d) striking of the thrust member against an axial stop; and e) operating the tamping beam device with a second stroke setting by transmitting the rotary movement of the drive shaft via the thrust member to the eccentric ring, wherein the direction of rotation of the rotating drive shaft in the second stroke setting is identical to the direction of rotation of the rotating drive shaft in the first stroke setting.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] The invention will be explained in more detail below by reference to the embodiment examples shown in the figures; In the schematic figures:
[0038] FIG. 1 is a side view of a road paver;
[0039] FIG. 2A is an oblique perspective view of a tamping beam device;
[0040] FIG. 2B is an oblique perspective view of a drive shaft of the tamping beam device shown in FIG. 2A with an eccentric device;
[0041] FIG. 2C is an enlarged detail view of the tamping beam device of FIG. 2A;
[0042] FIG. 3 is a cross-sectional view of the tamping beam device of FIG. 2A;
[0043] FIG. 4A is an enlarged detail view from FIG. 3 with a large stroke at top dead center; and
[0044] FIG. 4B is an enlarged detail view according to FIG. 4A with a small stroke at top dead center.
DETAILED DESCRIPTION
[0045] Like components are designated by like reference numerals in the figures, although recurring components may not necessarily be designated throughout the figures.
[0046] FIG. 1 initially illustrates the basic structure of a typical road paver 1. The main elements of the road paver 1 include a hopper 2, a drive motor 3, a paving screed 4, travel units 5 (wheels and/or crawler tracks) and an operator platform 6. In paving operation, the road paver 1 moves in working direction A over the underlying ground 9. The paving screed 4 is connected to the machine frame (not designated) of the road paver 1 via drawbars 7. In addition to its smoothing function, the paving screed 4 also has a compacting function. For this purpose, a tamping beam device 8 is arranged on the paving screed 4 as an additional device. The other figures relate to the structure and mode of operation of this tamping beam device 8.
[0047] FIG. 2A shows the tamping beam device in its entirety in an oblique perspective front view. In working operation, the tamping beam device 8 is thus guided in working direction A over the pavement to be installed. The tamping beam device 8 typically comprises a tamping beam 10, a connecting rod 11, a connecting plate 12, a drive shaft 13, a holding arm 14 and an eccentric device 17. The tamping beam 10 is usually also heatable by a heating element. This is shown in FIG. 2A through the heating element 16. In the embodiment example shown in FIG. 2A, the tamping beam 10 is mounted on the paving screed by a total of two tamping beam devices 8 via the holding arms 14. The two tamping beam devices 8 have the same functional design. The movement of the tamping beam 10 is a tamping/lifting movement in the direction of the double-headed arrow C. This movement is initiated by the drive shaft 13, which rotates clockwise or counterclockwise in the direction of rotation or orbital direction B about the rotation axis or orbital axis of the drive shaft 13. A corresponding drive device not shown in more detail is provided for this purpose, such as an electric or hydraulic motor or a suitable transmission gearbox.
[0048] This centric rotary movement is converted into an eccentric rotary movement using the eccentric device 17 and transmitted to the connecting rod 11. The eccentric crank movement is ultimately converted into the desired tamping movement of the tamping beam 10 via the connecting plate 12. For this purpose, the tamping beam 10 is guided accordingly on the screed 4 (not shown in detail in the figures). Corresponding guides are known in the prior art. Details of the design and operation of the eccentric device 17 are shown in the following figures. In particular, the eccentric device 17 is configured such that the lifting height, i.e., the extent of the tamping/lifting movement in the direction of the double-headed arrow C (i.e., in the vertical direction) can be adjusted in a stepless manner. For this purpose, a thrust member 20 which is axially adjustable on the drive shaft 13 is provided, by means of which a first and a second stroke setting of the tamping beam 10 can be adjusted. Typically, the thrust member 20 is a sleeve that can slide on the outer surface of the drive shaft 13.
[0049] As shown by way of example in FIGS. 2B and 3, the thrust member 20 has a first region 201 and a second region 202. The first region 201 is arranged in the eccentric device 17. The second region 202 is arranged outside the eccentric device 17. The second region 202 is connected to an axial adjustment device 30 via a thrust bearing 31, as shown, for example, in FIGS. 2A, 2C and 3. In particular, the thrust bearing 31 is provided between an adjustment ring 32 mounted on the second region 202 of the thrust member 20 and an actuating element 33 of the axial adjustment device 30. For example, a first end 331 of the actuating element 33 may at least partially engage around the adjusting ring 32, as can be seen in FIG. 2C. The first end 331 of the actuating element 33 may also be referred to as the head or head end of the actuating element 33.
[0050] According to one embodiment, which may be combined with other embodiments described herein, at least a first bearing 311 and a second bearing 312 are provided between the adjusting ring 32 and the actuating element (33), as shown by way of example in FIG. 2C. In particular, the first bearing 311 and the second bearing 312 are arranged opposite each other, preferably diametrically opposite each other. Typically, at least one contact-free region 314 between the adjusting ring 32 and the actuating element 33 is provided in the circumferential direction between the first bearing 311 and the second bearing 312. Typically, the first bearing 311 and the second bearing 312 are plain bearings formed by plain bearing contact surfaces between the adjusting ring 32 and the actuating element 33. Typically, at least the plain bearing contact surfaces of the adjusting ring 32 and the actuating element 33 are made of a plain bearing material, in particular a plain bearing plastic material.
[0051] As shown by way of example in FIG. 2C, the actuating element 33 may have one or more, in particular two or three, extensions 333. The extensions 333 are typically configured to engage in a recess 321, in particular a groove, of the adjusting ring 32. Typically, the groove is annular and is provided on an outer surface of the adjusting ring 32. The surface of the groove is typically made of a plain bearing material, in particular a plain bearing plastic material. According to one example, the adjusting ring 32 consists entirely of a plain bearing material, in particular a plain bearing plastic material. Further, the extensions 333 of the actuating element 33 are typically made of a plain bearing material, in particular a plain bearing plastic material. According to one example, the entire actuating element 33, or at least the actuating element head, may consist of a plain bearing material, in particular a plain bearing plastic material.
[0052] According to one embodiment, which may be combined with other embodiments described herein, a third bearing 313 is provided between the adjusting ring 32 and the actuating element 33, as shown by way of example in FIG. 2C. Typically, the third bearing 313 is arranged between the first bearing 311 and the second bearing 312. Preferably, the third bearing 313 is arranged centrally between the first bearing 311 and the second bearing 312. The third bearing 313 is typically a plain bearing and may be configured analogously to the first and second bearings.
[0053] According to an alternative embodiment, the first bearing 311 and/or the second bearing 312 and/or the third bearing 313 may be designed as rolling bearings, in particular axial rolling bearings. This is shown in FIG. 4A as an example for the region between the adjusting ring 32 and the actuating element 33.
[0054] As shown by way of example in FIG. 2C, the actuating element 33 is typically fixed to a rod 34 of the axial adjustment device 30. The rod 34 runs essentially parallel to the drive shaft 13. In other words, the rotation axis 131 of the drive shaft 13 and the central longitudinal axis 341 of the rod 34 are parallel to each other. Typically, a bushing 35 is arranged on the rod 34, which is connected to the second end 332 of the actuating element 33. Typically, the rod 44 is configured as a spindle shaft and the bushing 35 as a spindle nut, so that the spindle nut can be axially displaced by a rotary movement of the spindle shaft. Typically, the rod 34 of the adjustment device 30 is connected to a manual or motorized spindle drive, which is configured to rotate the rod 34 about the central longitudinal axis 341, whereby an axial adjustment of the thrust member 20 can be effected.
[0055] As can also be seen in FIGS. 2B and 3, the essentially cylindrical thrust member 20 sits at an angle on the drive shaft 13. This means that the inner passage of the thrust member 20, which is complementary to the outer surface of the drive shaft 13, does not run along the cylinder axis Z of the cylindrical outer surface of the thrust member 20, but coaxially to the rotation axis B. As a result, an inclined sliding surface is obtained with the outer surface of the thrust member, which interacts with the eccentric ring 18 in the manner described in more detail below.
[0056] FIG. 2B also shows that the thrust member 20 in the present embodiment example may have a receiving recess 29 in the outer surface for a key 21.
[0057] When the key 21 is arranged in the receiving recess 29, a projection 21 projecting from the outer surface of the thrust member in the radial direction is provided, which extends longitudinally in the direction of the cylinder axis Z and runs parallel to the latter on the outer surface of the thrust member 20. This projection ensures that the thrust member 20 is secured against rotation relative to the eccentric ring 18. Alternatively, the projection may also be provided as an integral part of the thrust member, i.e., without receiving recess 29 and key 21.
[0058] The connecting rod bearing 23 for the connecting rod is shown on the left-hand side in FIG. 2B. FIG. 2B illustrates that the eccentric ring is also a sleeve-shaped component that revolves around the thrust member 20 (relative to the rotation axis B). A guide groove 22 is provided in the eccentric ring 18, in which the projection of the thrust member 20, in particular the key 21, runs. As a result, the thrust member 20 and the eccentric ring 18 co-rotate with each other relative to the rotation axis B of the drive shaft 13. At the same time, however, the thrust member can be adjusted in the axial direction of the rotation axis B and thus displaced relative to the eccentric ring 20 in this direction. For this purpose, the length of the corresponding guide groove in the axial direction B is longer than the total extension of the projection. Due to the inclination of the outer surface of the thrust member 20 relative to the rotation axis B of the drive shaft, the eccentricity of the outer surface of the eccentric ring 18 is adjusted by such a longitudinal movement of the thrust member 20. In other words, the position of the contact surface between these two elements 18 and 20 changes as a result of the thrust adjustment of the thrust member 20 relative to the eccentric ring 18, so that a different eccentricity is achieved. This will be explained in more detail using the cross-sectional views below. The eccentric rotation of the eccentric ring 18 is transmitted to the connecting rod 11, which surrounds the eccentric ring on its outer surface. The existing eccentricity E is indicated in FIGS. 4A and 4B by the position of the cylinder axis Z in relation to the outer surface of the eccentric ring 18 or the connecting rod bearing 11, which is also annular.
[0059] FIG. 3 shows the embodiment example according to FIG. 2A in a cross-sectional view in a vertical plane along the rotation axis B of the drive shaft 13, and FIG. 4A shows an enlarged detail view of the framed region. FIGS. 3 and 4a illustrate first of all that, due to the configuration of the thrust member 20 and the eccentric ring 18 described above, a longitudinal movement of the thrust member 20 causes a radial adjustment of the eccentric ring 18 relative to the drive shaft 13. The inclined arrangement of the cylindrical surface of the thrust member 20 ultimately results in a sliding slope 24 on the thrust member 20. The eccentric ring rests against this sliding slope 24 with a correspondingly configured sliding guide, which corresponds to its inner surface. If the relative position of the thrust member 20 is now adjusted along the rotation axis B of the drive shaft 13 relative to the eccentric ring 18, the eccentric ring 18 slides along the sliding slope 24 of the thrust member 20 and is thus raised or lowered relative to the rotation axis B. This adjustment movement is driven by the axial adjustment device 30, which is connected to the thrust member 20 via the thrust bearing 31. FIG. 4A shows that the adjustment movement of the thrust member 20 can take place between the stops 26 and 27, which limit and seal the movement space or receiving space 28 within the eccentric ring 18 for the thrust member 20 in the axial direction of the rotation axis B on both sides.
[0060] FIGS. 4A and 4B relate to the two maximum possible stroke settings in the present embodiment example. FIGS. 4A and 4B each show a cross-sectional view through the eccentric device 17, in each case at a time when the connecting rod 11 or the eccentric device 17 has reached its top dead center. If the thrust member 20 is moved to the right on the drive shaft in this embodiment example and strikes against the stop 27 there, the distance in the horizontal plane, for example to the upper edge of the bracket 14, is H1 (this large stroke corresponds to twice the vertical distance between E and B in FIG. 4a). A rotary movement of the drive shaft 13 results in the eccentric ring 18 performing an eccentric rotary movement and thus causing the connecting rod 11 and ultimately the tamping beam not shown in FIG. 4A to perform the tamping movement. The position of the eccentric ring axis E, i.e., the axis that forms the central axis of the outer circumferential surface of the eccentric ring, is also shown in FIG. 4A for more detailed illustration. It can be clearly seen that this axis is parallel but not coaxial to the rotation axis B of the drive shaft 13.
[0061] If the thrust member 20 is displaced to the left on the drive shaft in the present embodiment example, as shown by way of example in FIG. 4B, and strikes against the stop 26 there, the distance in the horizontal plane, for example to the upper edge of the bracket 14, is H2. If the thrust member 20 is displaced from right to left, the eccentric ring slides along its sliding guide on the sliding slope of the thrust member 20 and its central axis Z approaches the rotation axis B of the drive shaft 13. This continues until the movement of the thrust member 20 along the drive shaft 13 is stopped by the stop 26. If the drive shaft 13 is rotated in the position shown in FIG. 4B, the eccentric ring 18 rotates about the drive shaft 13 with the reduced stroke H2.
[0062] A possible alternative embodiment also encompassed by the invention consists, for example, in connecting the actuating element 33 shown in FIG. 3 firmly to the rod 34 and displacing the rod 34 linearly in axial direction to achieve an axial adjustment. Instead of a rotational adjustment movement of the rod 34, in this case the rod 34 is thus moved axially or preferably parallel to the direction of rotation B. The spindle nut 35 and the configuration of the rod 34 as a threaded rod are then not required.
[0063] The rotational or linear adjustment movement of the rod 34 may be driven by a motor, for example by an electric, pneumatic or hydraulic motor, by means of a suitable actuator, for example a pneumatic or hydraulic cylinder or an electromagnetic actuator, or also manually, for example by means of a hand crank and/or a suitable lever mechanism. The rod 34 may also be configured as a toothed rack, for example. In particular, the corresponding drive device may be operatively connected to the rod 34 at at least one or both of its axial ends.
[0064] As can be seen from the embodiments described herein, a tamping beam device is advantageously provided which enables stroke adjustment in an improved manner. The option of stepless adjustment is particularly advantageous. Furthermore, a stroke adjustment is made possible in which material loads during the adjustment process can be reduced compared to solutions known from the prior art.
LIST OF REFERENCE NUMERALS
[0065] 1 road paver [0066] 2 hopper [0067] 3 drive motor [0068] 4 paving screed [0069] 5 travel units [0070] 6 operator platform [0071] 7 drawbars [0072] 8 tamping beam device [0073] 9 underlying ground [0074] 10 tamping beam [0075] 11 connecting rod [0076] 12 connecting plate [0077] 13 drive shaft [0078] 131 rotation axis of the drive shaft [0079] 14 holding arm [0080] 15 center region [0081] 17 eccentric device [0082] 18 eccentric ring [0083] 20 thrust member [0084] 201 first region of the thrust member [0085] 202 second region of the thrust member [0086] 21 projection/key [0087] 22 guide groove [0088] 23 connecting rod bearing [0089] 24 sliding slope [0090] 26 stop [0091] 27 stop [0092] 29 receiving recess [0093] 30 axial adjustment device [0094] 31 thrust bearing [0095] 311 first bearing [0096] 312 second bearing [0097] 313 third bearing [0098] 314 contact-free region [0099] 315 rolling bearing [0100] 32 adjusting ring [0101] 321 recess/annular groove [0102] 33 actuating element [0103] 331 first end of the actuating element [0104] 332 second end of the actuating element [0105] 333 extensions [0106] 34 rod [0107] 341 central axis of the rod [0108] 35 bushing [0109] A working direction [0110] B direction of rotation [0111] C tamping/lifting movement
