Tamping unit for track tamping machine

Abstract

The utility model relates to a tamping unit for a track tamping machine, which is used for tamping a plurality of adjacent sleepers (5) of a track (4) by means of a tamping tool (25), and the tamping tool can be immersed in a ballast bed (7) on two sides of a steel rail (3) of the track and can be pivotally supported on a height-adjustable tool carrier (22). The utility model is characterized in that it can be adjusted in pairs relative to one another by means of pressing drives (26, 27) and is coupled to a common vibration drive (24). The tamping tool, which can be immersed on one side of the rail, is coupled to a first eccentric shaft (40) of the vibration drive, the tamping tool, which can be immersed on the other side of the rail (3), is coupled to a second eccentric shaft (41) of the vibration drive, both eccentric shafts being driven by their own electric motors. This enables a simple and balanced solution for electrification of the vibration drive.

Description

Technical Field

[0001] The utility model relates to a tamping unit for a track tamping machine, the tamping unit is used to tamp a plurality of adjacent sleepers of a track by means of a tamping tool, the tamping tool can be immersed in a ballast bed on both sides of the rails of the track, the tamping tool can be pivotally supported on a height-adjustable tool carrier, can be adjusted in pairs relative to each other via a pressing drive (Beistellantriebe), and is connected to a common vibration drive. In addition, the utility model also relates to a corresponding method for tamping a plurality of adjacent sleepers of a track. Background Art

[0002] DE 1 287 100 B and EP 0 208 826 A1 each disclose a tamping unit for tamping a plurality of sleepers simultaneously on both sides of a rail of a track using a plurality of tamping tools. The tamping tools are pivotally supported on a common tool carrier and are connected to a common eccentric shaft via a compression drive for generating vibrations. In this way, a common vibration drive is assigned to all tamping tools, thereby reducing the number of components required.

[0003] With this tamping unit, the sleepers in front and immediately behind in the longitudinal direction of the track are tamped simultaneously. During the tamping process, a pair of front tamping tools tamp the sleepers in front and a pair of rear tamping tools tamp the sleepers in the rear. The tamping tools in front of each tamping tool pair are assigned to the first common eccentric section of the eccentric shaft, and the tamping tools in the rear of each tamping tool pair are assigned to the second common eccentric section of the eccentric shaft. In this way, the vibrating movements of the tamping tool pairs are synchronized with each other. The vibration drive for all tamping tools must provide sufficient power to keep the tamping tools vibrating during the immersion process and during the extrusion process (Beistellvorgang). With limited structural dimensions and weight, the required power is provided by a hydraulic motor.

[0004] Until now, only one electric vibration drive for a tamping unit for tamping sleepers has been known. For example, DE 24 17 062 A1 discloses a tamping unit in which an eccentric bearing sleeve is arranged in the swing arm of the tamping pick to generate vibrations. The rotational movement of a drive shaft driven by an electric motor is transmitted to the eccentric bearing sleeve via a chain drive.

[0005] AT 519934 A1 also discloses an electric vibration drive for a tamping unit, with which a single sleeper is tamped per tamping cycle. In this case, the rotor of the electric motor is directly connected to the eccentric shaft of the vibration drive. The stator of the electric motor is arranged in a flange-connected motor housing. The limited design dimensions determine the maximum possible power of the electric motor. Utility Model Content

[0006] The object of the invention is to provide a simple solution for electrifying the vibration drive for a tamping unit of the above-mentioned type. Another object of the invention is to provide a method for tamping a rail by means of a corresponding tamping unit.

[0007] These objects are achieved by the following features.

[0008] According to the utility model, a tamping unit for tamping a track is proposed, and the tamping unit is used to tamp a plurality of adjacent sleepers of the track by means of a tamping tool, the tamping tool can be immersed in the ballast bed on both sides of the rails of the track and can be pivotally supported on a height-adjustable tool carrier, and the tamping tool can be adjusted in pairs relative to each other via an extrusion drive and is connected to a common vibration drive. According to the utility model, the tamping tool that can be immersed on one side of the rail is connected to the first eccentric shaft of the vibration drive, and the tamping tool that can be immersed on the other side of the rail is connected to the second eccentric shaft of the vibration drive, wherein the two eccentric shafts are driven by their own electric motors. Thus, surprisingly, although the eccentric shaft and the eccentric shaft drive are doubled, a simple and balanced solution in terms of space requirements and weight distribution for electrifying the vibration drive is achieved. The separate installation of the two eccentric shafts in the eccentric shaft housing arranged on the common tool carrier enables the optimal dimensioning of the entire vibration drive. The strength of the corresponding eccentric shaft and its mounting are designed for the reaction forces acting from the ballast via the tamping tool. The compact and symmetrical arrangement achieved with respect to the vertical longitudinal plane of the track leads to a balanced distribution of forces and masses and prevents disruptive vibration loads on the tool carrier and other supporting elements of the tamping unit and, as a result, on the track tamping machine.

[0009] A further improvement in the operating characteristics is achieved by a further development in which two eccentric shafts are coupled to one another to achieve synchronous rotation. In this way, the vibration movements of all tamping tools are coordinated with one another so that no disruptive vibration superposition occurs.

[0010] Preferably, each electric motor is connected to its own frequency converter. The electric motors can thereby be connected to the power supply independently of one another. Each electric motor can be controlled individually, thereby enabling an optimal load distribution of the two electric motors and the eccentric shaft. This is particularly important for ballast beds with uneven hardness, when the reaction force of the tamping tool on one side of the rail differs significantly from the reaction force of the tamping tool on the other side of the rail.

[0011] In a further development, the corresponding electric motor is directly connected to the assigned eccentric shaft as a torque motor. A torque motor, also known as a torque motor or a direct drive motor, can provide a high torque even with a small size and a low speed. For this application, the permanent magnet brushless torque motor is preferably designed as an inner rotor.

[0012] In particular, the respective eccentric shaft with the rotor of the associated torque motor is supported only in the eccentric shaft housing, wherein the rotor is arranged on the section of the eccentric shaft that protrudes from the eccentric shaft housing, and wherein the stator of the torque motor is arranged in a motor housing connected to the eccentric shaft housing. This results in a particularly compact and weight-saving design of the vibration drive. The two rotors together act as an oscillating mass, which promotes uniform rotation and low torsional stresses on the eccentric shaft.

[0013] An improvement of this embodiment is that the respective rotor is connected to the assigned eccentric shaft by means of a force-fitting shaft-hub connection. This type of connection has several advantages. On the one hand, the rotor is positioned very precisely and securely on the eccentric shaft, and on the other hand, good removability is maintained so that the rotor can be quickly replaced if necessary. Exact positioning is important because it ensures a uniform gap between the rotor and the stator.

[0014] In a preferred variant of the utility model, the two eccentric shafts are connected to each other in a rotationally locked manner. Thus, even by simply controlling the two electric motors, good load distribution and synchronous rotation of the two eccentric shafts can be achieved.

[0015] Preferably, the two ends of the first eccentric shaft and the second eccentric shaft, which are arranged with a common rotation axis, facing each other are connected by means of a sleeve. Advantageously, a sleeve with external teeth is arranged at the respective eccentric shaft end. The shaft-hub connection between the respective sleeve and the associated eccentric shaft end is designed in particular in a form-fitting manner, for example by means of a guide key. The sleeve is designed with corresponding internal teeth, so that positioning the sleeve on the two sleeves results in a rotationally locked connection of the two eccentric shafts.

[0016] The eccentric shafts connected to each other in a rotationally locked manner are preferably driven in such a way that one electric motor is coupled to a motor controller provided for speed-controlled operation and the other electric motor is coupled to a motor controller provided for torque-controlled operation. In a superior master-slave arrangement, the motor controller of the speed-controlled electric motor is designed as a master and the motor controller of the torque-controlled electric motor is designed as a slave. The superior controller predetermines the desired speed for the speed-controlled operation of one electric motor. The torque generated thereby is distributed approximately evenly to the two eccentric shafts by the torque-controlled operation of the other electric motor, so that only a negligible torsional stress acts on the connection between the two eccentric shafts.

[0017] In this variant, a pulse generator is advantageously arranged on at least one of the two eccentric shafts, wherein a sensor associated with the pulse generator is arranged in the eccentric shaft housing. In this way, the two eccentric shafts connected to each other in a rotationally locked manner can be controlled in a speed-controlled manner by the sensor detecting a sensor signal that is proportional to the actual speed. In a simpler speed-controlled variant, a frequency converter is provided to control the assigned electric motor without the need for feedback of the sensor signal. This type of control is also stable against load step changes and achieves sufficient speed accuracy within a predetermined speed regulation range.

[0018] In another preferred variation of the utility model, two eccentric shafts are connected only by means of a common control device of an electric motor, wherein each eccentric shaft is assigned a sensor for determining position, and wherein the common control device is assigned a corresponding sensor signal to synchronously control the electric motor. This variation allows other operating modes in addition to synchronous rotation and uniformly distributed torque. For example, a phase-shifted rotation or counter-rotation of the two eccentric shafts is performed, which can produce smaller vibration loads on the tool carrier, on other bearing elements of the tamping unit, and subsequently on the track tamping machine. In addition, if necessary, for each eccentric shaft, a separate load-related control can be implemented. Thus, it is possible to react to different hardness areas of the ballast bed on both sides of the rail. For example, when the assigned tamping tool acts on a side with an increased ballast bed hardness, the rotation speed and / or torque can be increased only for one eccentric shaft.

[0019] In a method according to the invention for tamping a track with sleepers supported in a ballast bed and rails fixed to the sleepers by means of a tamping unit according to one of the described embodiments, the tamping unit is positioned above a plurality of immediately adjacent sleepers, wherein a tool carrier with a tamping tool is lowered and a tamping tool with a tamping pick is immersed in the ballast bed, wherein the tamping pick is moved relative to one another by means of a pressing drive, and wherein, at least for the duration of the lowering process and the pressing process, an eccentric shaft is driven by two electric motors to apply vibrations to the tamping tool. The method ensures that during simultaneous immersion in a plurality of sleeper intervals and during the placement of the tamping pick under a plurality of sleepers, vibrations are maintained even in the case of high reaction forces of the ballast, and that a uniform load acts on the tamping unit and its components. In particular, a uniform load distribution is ensured by the distribution to two eccentric shafts and by the common operation of the two electric motors.

[0020] Advantageously, each of the two electric motors is operated with its own frequency converter, wherein the frequency converters are controlled in a coordinated manner with one another. As a result, the control of the electric motors can be flexibly adapted to changing operating situations.

[0021] Preferably, in a variant of the eccentric shafts connected to one another in a rotationally locked manner, one eccentric shaft is driven in a speed-controlled manner by means of an associated motor controller, and the other eccentric shaft is driven in a torque-controlled manner by means of an associated motor controller. This ensures that, at a predetermined speed, both eccentric shafts are loaded with the same torque. The rotationally locked connection between the two eccentric shafts thus remains largely free of torsion loads.

[0022] In another variant with eccentric shafts coupled only by means of a control device, the position of the respective eccentric shaft is advantageously determined by means of sensors, wherein the respective sensor signals are fed to the control device, and wherein the electric motor is controlled by means of the control device based on the sensor signals, in particular synchronously. With this method, the two electric motors can be controlled in different ways. In addition to the preferred synchronous operation, in other operating modes, a phase-shifted or opposite rotation of the two eccentric shafts is also provided. This makes it possible to optimize the vibrations transmitted to the ballast while protecting the device components. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in detail by way of example with reference to the accompanying drawings. In the accompanying drawings:

[0024] Figure 1 A track tamping machine on a track is schematically shown;

[0025] Figure 2 A tamping unit for tamping two sleepers is schematically shown in a side view;

[0026] Figure 3 The tamping unit is schematically shown in a front view;

[0027] Figure 4 The schematic diagram shows an eccentric shaft housing with two eccentric shafts, which are connected to one another in a rotationally locked manner by means of sleeves;

[0028] Figure 5 Schematically shows an eccentric shaft housing with two eccentric shafts, which are coupled to each other via a common control device;

[0029] Figure 6 Schematically shows a method for having Figure 4 The control circuit diagram of the two tamping units with eccentric shaft arrangement shown;

[0030] Figure 7 Schematically shows a method for having Figure 5 The control circuit diagram of the two tamping units with eccentric shaft arrangement shown;

[0031] Figure 8 Schematically shows a method for having Figure 5 An alternative control circuit diagram of two tamping units with an eccentric shaft arrangement is shown. DETAILED DESCRIPTION

[0032] Figure 1 The track tamping machine 1 shown in the figure comprises two tamping units 2, each of which is assigned to a rail 3 of the track 4 to be tamped. The rails 3 are fixed on sleepers 5, which are installed in the ballast bed 7 at intervals along the longitudinal direction 6 of the track. The track tamping machine 1 designed for continuous operation comprises a main machine part 8 and a tamping satellite trolley 9, on which the tamping units 2 and the track-lifting and shifting units 10 are arranged. The tamping satellite trolley 9 is mounted on the main machine part 8 with longitudinal guides at the front and guided on the track 4 with a track running gear 11 at the rear. The main machine part 8 comprises a machine frame 12, which is supported on the other track running gear 11. The electric traction drive 13 of the track tamping machine 1 is supplied with electrical energy from the overhead line 15 of the track 4 via a pantograph 14. An electrical storage unit 16 is provided to bridge this power supply.

[0033] During operation, the main machine part 8 is continuously moved along the track 4 in the working direction 17, while periodically moving the tamping satellite trolley 9 forward. In the example shown, the tamping unit 2 is arranged for tamping two immediately adjacent sleepers 5 at the same time. Other tamping units 2 for tamping more than two sleepers 5 at the same time are also covered by the present invention.

[0034] The tamping cycle begins with positioning the tamping unit 2 above the two sleepers 5 to be tamped. The track section between the track running gear 11 is then lifted and laterally aligned by means of the track lifting and shifting unit 10. The measuring system 18 installed on the track tamping machine 1 is used to control the track lifting and shifting unit 10 in order to achieve a predetermined target position of the track 4. In this target position, the ballast is pushed under the lifted sleepers 5 by means of the tamping unit 2 and compacted. In this way, the track 4 is fixed in the desired position.

[0035] Figure 2 An exemplary tamping unit 2 is shown in FIG. 2 for simultaneously tamping two adjacent sleepers 5 during a tamping process. Figure 3 Two such tamping units 2 are shown in a front view in a raised position, each of which is assigned to one of the two rails 3 of a track 4 .

[0036] A transverse guide 20 is located on the supporting frame 19 of the tamping satellite trolley 9, on which the unit frame 21 of the corresponding tamping unit 2 is arranged so that the unit frame 21 can be moved laterally. A tool carrier 22 is mounted on a vertical guide 23 of the corresponding unit frame 21. A vibration drive 24 and a pivotable tamping tool 25 are arranged on the tool carrier 22. The tamping tools 25 can be adjusted in pairs relative to each other via squeeze drives 26, 27 and can be connected to a common vibration drive 24.

[0037] When viewed in the longitudinal direction 6 of the rail relative to the working direction 17, the respective tamping unit 2 comprises two front tamping tool pairs 28 for tamping the front sleeper 5 and two rear tamping tool pairs 29 for tamping the rear sleeper 5. The two front tamping tool pairs 28 and the two rear tamping tool pairs 29 are arranged for simultaneous immersion on both sides, i.e. the inner side 30 and the outer side 31 of the assigned rail 3. The inner side 30 and the outer side 31 of the respective rail 3 are defined relative to the rail center axis 32. Thus, during the tamping process, a pair of tamping tools of the front tamping tool pair 28 and a pair of tamping tools of the rear tamping tool pair 29 are immersed on the inner side 30 and the outer side 31 of the assigned rail 3, respectively.

[0038] Preferably, each tamping tool 25 comprises two tamping picks 33, which are fixed in a pick seat 34 of a pivot arm 35. The pivot arm 35 of the respective tamping tool 25 is pivotably mounted on the tool carrier 22 about a pivot axis 36, which is aligned horizontally and transversely to the rail center axis 32. The lower lever arm comprises the pick seat 34, and the upper lever arm is connected to the associated pressing drive 26, 27.

[0039] The front tamping tool pair 28 and the rear tamping tool pair 29 are arranged substantially symmetrically with respect to a vertical transverse plane 37. Symmetry also exists with respect to a vertical longitudinal plane 38.

[0040] The arrangement of the tamping tool 25 that can be lowered on one side of the inner side 30 and the outer side 31 is described in more detail below. The front tamping tool 25 of the front tamping tool pair 28 and the rear tamping tool 25 of the rear tamping tool pair 29 are connected to the vibration drive 24 via a long squeeze drive 26 and via an eccentric arm 39, respectively. The corresponding eccentric arm 39 is mounted on the assigned eccentric shaft of the vibration drive 24 and is connected to the assigned long squeeze drive 26 in an articulated manner. The rear tamping tool 25 of the front tamping tool pair 28 and the front tamping tool 25 of the rear tamping tool pair 29 are connected to the vibration drive 24 via a short squeeze drive 27, respectively.

[0041] Advantageously, the short extrusion drive 27 assigned to the front tamping tool 25 in the rear tamping tool pair 29 and the eccentric arm 39 assigned to the front tamping tool 25 in the front tamping tool pair 28 form a rigid unit with a common bearing on the assigned eccentric shaft. In a corresponding manner, this also applies to the rear tamping tools 25 of the two tamping tool pairs 28, 29.

[0042] In this case, the two front tamping tools 25 are assigned to a common first eccentric section 42, and the two rear tamping tools 25 are assigned to a common second eccentric section 43 of the same eccentric shaft. The eccentricities of the two eccentric sections, namely the first eccentric section 42 and the second eccentric section 43, are arranged approximately 180° apart from each other, so that the tamping tools 25 of the respective tamping tool pairs 28, 29 vibrate in opposite directions during operation.

[0043] All tamping tools 25 of the respective tamping unit 2 are mounted on a common tool carrier 22, which is height-adjustable relative to the assigned unit frame 21 by means of a height-adjusting drive 44. In this way, the tool carrier 22 with the tamping tools 25 can be lowered in the direction of the ballast bed 7, wherein the tamping pick 33 with the pick plate located at the end is immersed in the ballast bed 7 up to below the lower edge of the sleeper 5. Then, the immersion process takes place, wherein the long pressing drive 26 pushes the upper lever arm of the assigned tamping tool 25 outwards and the short pressing drive 27 pulls the upper lever arm of the assigned tamping tool 25 inwards. This is achieved by corresponding pressurization of the pressing drives 26, 27, which are designed as hydraulic cylinders.

[0044] During the lowering process and the squeezing process, the tamping tool 25 is vibrated by means of the vibration drive 24. According to the utility model, two connected first eccentric shafts 40 and second eccentric shafts 41 are arranged in the vibration drive 24, wherein each eccentric shaft is driven by its own electric motor 45. The rotational movement of the corresponding eccentric shaft is converted into the vibration movement of the tamping tool 25 by the squeezing drive 27 and the eccentric arm 39 mounted on the first eccentric section 42 and the second eccentric section 43. The eccentric arm 39 and the squeezing drive 26, 27 serve as transmission elements here, wherein the squeezing drive 26, 27 superimposes the squeezing movement or return movement (Beistell-oder Rückstellbewegung) on ​​the vibration movement of the tamping tool 25 by shortening or lengthening, in particular by retracting or extending the piston rod.

[0045] Figure 4 and Figure 5 Two variants of a vibration drive device 24 with two eccentric shafts and two electric motors 45 are shown in FIG. Advantageously, the corresponding arrangement is symmetrical with respect to the vertical plane of symmetry, resulting in a simple structure and uniform loading of the stressed components. In addition, it is also important to distribute the drive power to the two electric motors 45. In particular, the electric motor 45 is configured as a torque motor and is directly connected to the first eccentric shaft 40 and the second eccentric shaft 41. The smaller structural dimensions and the smaller weight of the corresponding electric motor 45 enable a compact and balanced construction of the vibration drive device 24. In addition, such a vibration drive device 24 can be simply integrated into the tool carrier structure. Preferably, the eccentric shaft housing 46 in which the first eccentric shaft 40 and the second eccentric shaft 41 are mounted is directly attached to the tool carrier 22. The components of the eccentric shaft housing 46 can also be configured as an integral component of the tool carrier 22.

[0046] In accordance with Figure 4In the exemplary embodiment of the present invention, the first eccentric shaft 40 and the second eccentric shaft 41 are arranged with a common rotation axis 47 and are connected to each other in a rotationally locked manner by means of a sleeve 48. Each eccentric shaft has two bearing locations 49, wherein the first eccentric section 42 and the second eccentric section 43 are arranged between these bearing locations 49. Preferably, the first eccentric section 42 is divided into two subsections and the second eccentric section 43 is arranged between the two subsections. The pressing drive 27 and the eccentric arm 39 are mounted in the form of a fork head on a subsection of the first eccentric section 42 and in the form of an articulated lug on the second eccentric section 43.

[0047] In the example shown, the first eccentric shaft 40 and the second eccentric shaft 41 are mounted by means of rolling bearings in a split bearing seat of an eccentric shaft housing 46. The top of the eccentric shaft housing 46 is closed by means of a housing cover 50. Via lateral openings in the eccentric shaft housing 46, the connection of the pressing drive 27 and the eccentric arm 39 to the associated eccentric shaft is guided.

[0048] At the first eccentric section 42 and the second eccentric section 43, the respective eccentric shaft has a larger diameter than at the bearing point 49, so that an optimum ratio between weight and bending stiffness is produced. The ends of the first eccentric shaft 40 and the second eccentric shaft 41 facing each other protrude with an end section beyond the respective bearing point 49. Preferably, a sleeve 51 is arranged in a rotationally locked manner on the respective end section by means of a guide key 52. ​​The respective sleeve 51 has an external toothing, in which the internal toothing of the sleeve 48 engages, wherein the sleeve 48 is pushed onto the sleeve 51. The sleeve 48 is laterally held by means of a locking ring 53.

[0049] On the other side of the respective eccentric shaft, the end section likewise projects beyond the respective bearing point 49 and out of the eccentric shaft housing 46. The rotor 55 of the associated electric motor 45 is connected to this end section by means of a force-fitting shaft-hub connection 54. The respective rotor 55 is supported here only at two bearing points 49 in the eccentric shaft housing 46 together with the associated eccentric shaft. Additional bearings would complicate the construction and have a negative impact on the weight and load conditions.

[0050] The force-fitting shaft-hub connection 54 comprises three sleeves, namely a first sleeve 56, a second sleeve 57 and a third sleeve 58. The first sleeve 56 is centered on the stepped section of the assigned eccentric shaft and is connected to the rotor 55 in a rotationally locked manner. In addition, the first sleeve 56 is arranged on the second sleeve 57 by means of a fit. The second sleeve 57 has a conical inner surface, which is pushed onto the corresponding conical outer surface of the third sleeve 58. The second sleeve 57 and the third sleeve 58 are arranged together on another stepped section of the assigned eccentric shaft. By axially clamping the third sleeve 58 on the second sleeve 57 by means of a threaded connection, a force-fitting interference fit is produced. This connection ensures an exact centering of the rotor 55 and can be loosened if necessary by axially pushing the third sleeve 58 away from the second sleeve 57 with a screw. As a result, the motor can be easily replaced.

[0051] The motor housing 59 of the respective electric motor 45 is directly connected to the eccentric shaft housing 46. A shaft seal 60 seals the motor housing 59 relative to the associated eccentric shaft. The stator 61 of the respective electric motor 45 is arranged in the motor housing 59. Preferably, a liquid cooling device is provided in the motor housing 59, so that even under high loads, despite its small structural size, the temperature of the electric motor 45 can be kept within an optimal range. The housing cover 50 closes the motor housing 59 from the outside.

[0052] Preferably, an encoder disk 62 for a sensor 63 is arranged on at least one of the first eccentric shaft 40 and the second eccentric shaft 41. At least one pulse generator 64 for the sensor 63 is configured on the encoder disk 62, for example in the form of a recess on the outer circumference. As soon as the edge of the recess passes the sensor 63 arranged in the eccentric shaft housing 46, the sensor 63 reports the corresponding phase position as a sensor signal to the control device 65. In this way, synchronization of the first eccentric shaft 40 and the second eccentric shaft 41 of the two tamping units 2 can be carried out, thereby minimizing vibrations that react on the supporting frame 19. If each vibration drive 24 is controlled separately, the sensor 63 and the encoder disk 62 are not required.

[0053] Preferably, each electric motor 45 is assigned a motor controller 66 for controlling the switching elements of its own frequency converter 67. With this individual frequency converter 67, the respective electric motor 45 is connected to an electrical energy source 68. For example, the power supply is provided by a railway transformer that can be connected to the overhead line 15 via the pantograph 14. The frequency converter 67 is then connected to an AC supply voltage of, for example, 400 V and 50 Hz.

[0054] Figure 6 The following table shows the Figure 42. Exemplary control of the electric motors 45 of two tamping units 2 with corresponding vibration drive devices 24. Each tamping unit 2 comprises two electric motors 45, which are connected to each other via connected eccentric shafts. One of the two electric motors 45 is operated in a speed-controlled manner by means of an assigned motor controller 66. The target speed is predetermined for the motor controller 66 by means of a superior machine control unit 69. For the immersion process, the target speed is, for example, 2700 rpm, which results in a vibration frequency of 45 Hz. During the extrusion process, a reduced target speed of 2100 rpm is predetermined, which results in a vibration frequency of 35 Hz. In a simple form without an encoder disk 62 and without a sensor 63, the motor controller 66 controls the assigned electric motor 45 using a stored control logic so as to reach the desired target speed. The assigned frequency converter 67 is set for speed control without feedback. According to the stored control logic, the frequency converter 67 not only adjusts the frequency, but also adjusts the amplitude of the output voltage. In an advantageous embodiment, the motor speed is controlled using the sensor signal from the sensor 63 .

[0055] The second electric motor is operated under torque control by means of the assigned motor controller 66. Thus, the motor controller 66 follows the other motor controller 66 according to the master-slave principle. The second electric motor inevitably rotates at a predetermined speed and applies the same torque to the assigned eccentric shaft as the first electric motor uses when driving the other eccentric shaft. The torque is adapted here by detecting the current flowing in the frequency converter 67 and the applied voltage and / or by direct detection by means of a torque sensor. For this purpose, both frequency converters 67 are connected to the superordinate components of the control device 65 and / or the sensor device.

[0056] In accordance with Figure 5 In another variant of the vibration drive 24, the first eccentric shaft 40 and the second eccentric shaft 41 are not connected in a rotationally locked manner. Here, the first eccentric shaft 40 and the second eccentric shaft 41 are connected only via a common control device 65. In addition, each eccentric shaft is assigned its own encoder disk 62 and its own sensor 63. In addition, the structure is similar to Figure 4 The structure in corresponds to .

[0057] Figure 72 shows an exemplary control of two tamping units 2 with such a vibration drive 24. The sensor signals of the two sensors 63 of the respective vibration drive 24 are evaluated in an evaluation circuit 70 by means of a common control device 65. This is done either individually for each tamping unit 2 or, if synchronization of all eccentric shafts is desired, jointly for both tamping units 2. In a simple design, it is sufficient to coordinate the vibration movements in each tamping unit 2 with one another so that no disruptive reactions occur on the supporting frame 19.

[0058] In the corresponding vibration drive 24, the alignment of the two encoder disks 62 relative to each other is known. As a result, the phase position of the first eccentric shaft 40 and the second eccentric shaft 41 can be directly inferred from the sensor signal. In order to ensure synchronous driving of the first eccentric shaft 40 and the second eccentric shaft 41, coordinated control is performed based on the detected sensor signals by means of the assigned motor controller 66.

[0059] In the simplest case, the respective encoder disk 62 has only one pulse generator 64. As soon as the pulse generator 64 of the first encoder disk 62 passes the assigned sensor 63, the corresponding sensor signal is recorded in the control device 65, in particular in the evaluation circuit 70. This process is carried out in the same way with the second encoder disk 62, wherein the corresponding sensor signal is also recorded in the control device 65. Then, control by means of the motor controller 66 is carried out by changing the speed within a predetermined target speed range until the two sensor signals appear synchronously. Then, synchronous operation is achieved.

[0060] With this control, phase-shifted or reversed driving of the first eccentric shaft 40 and the second eccentric shaft 41 can also be achieved. For phase-shifted operation, for example, a delay time corresponding to the desired phase shift is predetermined between two recorded time points indicating a complete rotation of the respective eccentric shafts.

[0061] In such Figure 8In the simpler control shown, the corresponding sensor signal is fed directly to the assigned motor controller 66. The connection is achieved via a common clock generator 71. In order to achieve synchronous operation, the motor controller 66 changes the speed within a predetermined target speed range until the recording time of the sensor signal coincides with a predetermined clock (Takt). Here, a phase shift can also be set by combining a predetermined clock signal with a delay time. An electric motor 45 of the corresponding vibration drive 24 is driven according to a predetermined clock signal (Taktsignal), and the motor controller 66 of another electric motor 45 additionally takes into account the set delay time. The corresponding predetermination is achieved, for example, by a superior machine control unit 69, which can also be set to predetermine a clock time (Taktvorgabe).

Claims

1. A tamping unit for a track tamping machine, the tamping unit being used for tamping a plurality of immediately adjacent sleepers (5) of a track (4) by means of a tamping tool (25), the tamping tool (25) being capable of being immersed in a ballast bed (7) on both sides of a rail (3) of the track (4) and being pivotably supported on a tool carrier (22) which is adjustable in height, the tamping tool (25) being adjustable in pairs relative to one another via a squeezing drive (26, 27) and being coupled to a common vibration drive (24), characterized in that The tamping tool (25) capable of being immersed on one side of the rail (3) is connected to a first eccentric shaft (40) of the vibration drive device (24), and the tamping tool (25) capable of being immersed on the other side of the rail (3) is connected to a second eccentric shaft (41) of the vibration drive device (24), and both eccentric shafts are driven by their own electric motors.

2. The tamping unit for a track tamping machine according to claim 1, characterized in that The two eccentric shafts are coupled to each other to achieve synchronous rotation.

3. The tamping unit for a track tamping machine according to claim 1 or 2, characterized in that: Each electric motor is connected to its own frequency converter (67).

4. The tamping unit for a track tamping machine according to claim 1 or 2, characterized in that: The respective electric motor is connected directly to the associated eccentric shaft as a torque motor.

5. The tamping unit for a track tamping machine according to claim 4, characterized in that The respective eccentric shaft with the rotor (55) of the associated torque motor is supported only in the eccentric shaft housing (46), the rotor (55) being arranged on the section of the eccentric shaft protruding from the eccentric shaft housing (46), and the stator (61) of the torque motor being arranged in a motor housing (59) connected to the eccentric shaft housing (46).

6. The tamping unit for a track tamping machine according to claim 5, characterized in that The respective rotor (55) is connected to the associated eccentric shaft by means of a friction-locking shaft-hub connection (54).

7. The tamping unit for a rail tamping machine according to claim 2, characterized in that: The two eccentric shafts are connected to one another in a rotationally locked manner.

8. The tamping unit for a rail tamping machine according to claim 7, characterized in that Two ends of the first eccentric shaft (40) and the second eccentric shaft (41) which are arranged with a common rotation axis (47) and which face each other are connected by means of a sleeve (48).

9. The tamping unit for a track tamping machine according to claim 7 or 8, characterized in that: One electric motor is coupled to a motor controller (66) provided for speed-controlled operation, and the other electric motor is coupled to a motor controller (66) provided for torque-controlled operation.

10. The tamping unit for a rail tamping machine according to claim 5, characterized in that A pulse generator (64) is arranged on at least one of the two eccentric shafts, and a sensor (63) associated with the pulse generator (64) is arranged in the eccentric shaft housing (46).

11. The tamping unit for a rail tamping machine according to claim 2, characterized in that: The two eccentric shafts are coupled only by means of a common control device (65) of the electric motors, each eccentric shaft being assigned a sensor (63) for determining the position, and the common control device (65) being assigned corresponding sensor signals for synchronous control of the electric motors.

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